Washington Washington Workshop 3,4 Dec Workshop 3,4 Dec 2001 2001 MRO Radar Workshop MRO Radar Workshop Prepared by: Prepared by: Enrico Flamini/Leila V. Lorenzoni – ASI – Enrico Flamini/Leila V. Lorenzoni – ASI – project office project office Angioletta Coradini – CNR – Angioletta Coradini – CNR – ASI project scientist ASI project scientist Roberto Seu – INFOCOM – Roberto Seu – INFOCOM – Team Leader Team Leader Arturo Masdea – INFOCOM – Arturo Masdea – INFOCOM – Experiment Manager Experiment Manager Roberto Orosei – CNR – Roberto Orosei – CNR – Science Team Science Team
Transcript
Slide 1
Washington Workshop 3,4 Dec 2001 MRO Radar Workshop Prepared
by: Enrico Flamini/Leila V. Lorenzoni ASI project office Angioletta
Coradini CNR ASI project scientist Roberto Seu INFOCOM Team Leader
Arturo Masdea INFOCOM Experiment Manager Roberto Orosei CNR Science
Team
Slide 2
Washington Workshop 3,4 Dec 2001 MRO Radar Workshop:
BACKGROUND
Slide 3
Washington Workshop 3,4 Dec 2001 Shallow Radar for Martian
Subsurface Studies: ASI AO Process & Selection
Slide 4
ASI AO Process & Selection Following the ASI -NASA
agreements of the SOI the AO-01-ASI-UPS- Mars Reconnaissance
Orbiter 2005 has been issued by ASI on the 26 th June 2001Following
the ASI -NASA agreements of the SOI the AO-01-ASI-UPS- Mars
Reconnaissance Orbiter 2005 has been issued by ASI on the 26 th
June 2001 ASI AO was dedicated to Teams and not single proposerASI
AO was dedicated to Teams and not single proposer One proposal has
been received :One proposal has been received : Subsurface Sounding
SHAllow RAdar SHARAD Subsurface Sounding SHAllow RAdar SHARAD This
AO was also timed wrt the annual ASI AO for scientific proposals
allowing a good scheduling from the budget point of viewThis AO was
also timed wrt the annual ASI AO for scientific proposals allowing
a good scheduling from the budget point of view
Slide 5
ASI AO Process & Selection The proposal due date was 23
JulyThe proposal due date was 23 July The proposal was formed by
two parts:The proposal was formed by two parts: Part 1
Investigation and techical Plan Part 2 Management and Cost Plan
Plus an Executive summary A four members Evaluation Board has been
appointed by the ASI Science Director composed by: A four members
Evaluation Board has been appointed by the ASI Science Director
composed by: Dr. A. Coradini Dr. L. Guerriero Dr. J. Campbell Dr.
E. Flamini The Selection was communicated to the Team Leader on
Septeber 15 thThe Selection was communicated to the Team Leader on
Septeber 15 th
Slide 6
ASI AO Process & Selection SELECTION GUIDELINES a)
Scientific Quality ( A = excellent; B = very good; C = good/fair; D
= poor ) ( A = excellent; B = very good; C = good/fair; D = poor )
Scientific quality, timeliness, noveltyScientific quality,
timeliness, novelty Impact on the advancement of the fieldImpact on
the advancement of the field Clarity of proposed goalsClarity of
proposed goals Credibility of proposed programs vs goalsCredibility
of proposed programs vs goals International impact and
visibilityInternational impact and visibility
Slide 7
ASI AO Process & Selection b)Proposers Scientific quality,
international standing of proposing groupsScientific quality,
international standing of proposing groups Credibility of proposing
teams vs proposed project and goalsCredibility of proposing teams
vs proposed project and goals Level and quality of team's national
and international collaborations and networkingLevel and quality of
team's national and international collaborations and networking
Past achievements in the specific filedPast achievements in the
specific filed
Slide 8
ASI AO Process & Selection c)Space research-related
Advantage/need to use space-based vs ground-based
approachAdvantage/need to use space-based vs ground-based approach
Timeliness/novelty for space
research/applicationsTimeliness/novelty for space
research/applications Educational/training value for space-related
aspectsEducational/training value for space-related aspects
Connection to previously funded activities by ASI/ESAConnection to
previously funded activities by ASI/ESA Impact on ASI
visibilityImpact on ASI visibility Impact on general and basic
knowledge and know-how Impact on general and basic knowledge and
know-how Impact on technology and technology transfer (industrial
aspects)Impact on technology and technology transfer (industrial
aspects) Impact on socio-economics aspectsImpact on socio-economics
aspects Synergies with other
programs/institutions/universitiesSynergies with other
programs/institutions/universities
Slide 9
ASI AO Process & Selection The conclusions of the
Evaluation Board have been reported in :The conclusions of the
Evaluation Board have been reported in : Rapporto del Gruppo di
Valutazione AO-01-ASI-UPS- Mars Reconnaissance Orbiter 2005 The EB
quoted the Proposal as fully in compliance wrt the AO and of high
scientific merit and to be fully funded
Slide 10
ASI AO Process & Selection SHARAD
Slide 11
Washington Workshop 3,4 Dec 2001 Shallow Radar for Martian
Subsurface Studies: Scientific rationale
Slide 12
Why a Sounder? Italian Space Agency ASI selected to propose a
radar sounder for the following reasons: Scientific value of this
experiment able to complete and enlarge MRO scientific output
including subsurface in the investigationScientific value of this
experiment able to complete and enlarge MRO scientific output
including subsurface in the investigation Possibility to complete
and extend similar investigations in which Italian Scientist were
already involved (MARSIS sounder on Mars Express
Mission)Possibility to complete and extend similar investigations
in which Italian Scientist were already involved (MARSIS sounder on
Mars Express Mission) Experience of Italian Scientists in the field
Experience of Italian industry/scientific groups in developing the
needed hardwareExperience of Italian industry/scientific groups in
developing the needed hardware
Slide 13
Scientific Value: subsurface access Geomorphicevidence and
theoretical arguments suggest that the Martian crust is water-rich
and may possess a complex stratigraphy of saturated and unsaturated
frozen ground, massive segregated bodies of ground ice, liquid
groundwater, and gas hydrates within the top 10 km of Martian
crust. Geomorphic evidence and theoretical arguments suggest that
the Martian crust is water-rich and may possess a complex
stratigraphy of saturated and unsaturated frozen ground, massive
segregated bodies of ground ice, liquid groundwater, and gas
hydrates within the top 10 km of Martian crust. Analysis of the
science of subsurface water on Mars is needed in understanding how
Martian hydrosphere evolved.Analysis of the science of subsurface
water on Mars is needed in understanding how Martian hydrosphere
evolved. However not many methods exist to access the Martian
subsurfaceHowever not many methods exist to access the Martian
subsurface (Houston 2001- Geomars)(Houston 2001- Geomars) Radar
sounders are among the few experiments able to access
subsurface
Slide 14
Scientific value: subsurface geology SHARAD radar should make
significant new scientific data available toward addressing
critical scientific problems on Mars, including the existence and
distribution of buried paleochannels, regolith layering.SHARAD
radar should make significant new scientific data available toward
addressing critical scientific problems on Mars, including the
existence and distribution of buried paleochannels, regolith
layering. It will also provide an improved understanding of the
electromagnetic properties of the stealth Martian subsurface,
further insights into the nature of patterned ground, and other
morphologies suggestive of the presence of water at present or in
the past.It will also provide an improved understanding of the
electromagnetic properties of the stealth Martian subsurface,
further insights into the nature of patterned ground, and other
morphologies suggestive of the presence of water at present or in
the past. Nanedi Valles Inca City
Slide 15
Polar Regions In addition, it should be possible to answer
certain kinds of geologic questions, such as the character of the
surface below the polar ice caps and the nature of some of the
layered terrain.In addition, it should be possible to answer
certain kinds of geologic questions, such as the character of the
surface below the polar ice caps and the nature of some of the
layered terrain. Layers in the South Polar Ice Cap. This is spring
time and the ice cap is retreating. The box shows a Mariner frame
for context. The resolution is 25m/pixel and the scene is 15x14 km.
Subframe of MOC Image #7709. Part of the permanent South Pole ice
cap. The resolution is 50 m/pixel; the scene is 30 x 29 km.
Slide 16
Scientific value: subsurface geology Globally, depth of
penetration could vary from tens of meters in materials with high
losses (wet clays or brines), or as deep as 5 km in homogeneous,
low-loss polar ice.Globally, depth of penetration could vary from
tens of meters in materials with high losses (wet clays or brines),
or as deep as 5 km in homogeneous, low-loss polar ice. SHARAD radar
should make significant new scientific data available toward
addressing critical scientific problems on Mars, including the
existence and distribution of buried paleochannels, regolith
layering.SHARAD radar should make significant new scientific data
available toward addressing critical scientific problems on Mars,
including the existence and distribution of buried paleochannels,
regolith layering. It will also provide an improved understanding
of the electromagnetic properties of the stealth Martian
subsurface, further insights into the nature of patterned ground,
and other morphologies suggestive of the presence of water at
present or in the past.It will also provide an improved
understanding of the electromagnetic properties of the stealth
Martian subsurface, further insights into the nature of patterned
ground, and other morphologies suggestive of the presence of water
at present or in the past. In addition, it should be possible to
answer certain kinds of geologic questions, such as the character
of the surface below the polar ice caps and the nature of some of
the layered terrain.In addition, it should be possible to answer
certain kinds of geologic questions, such as the character of the
surface below the polar ice caps and the nature of some of the
layered terrain.
Slide 17
Scientific Value: subsurface water detection The surface of
Mars will not be uniformly amendable to using radar sounding in the
search for waterThe surface of Mars will not be uniformly amendable
to using radar sounding in the search for water It will be possible
to find conditions of favorable radar viewing geometry, interface
scattering, surface and volume scattering, and material properties,
which may allow us to see useful reflections of aqueous layers from
orbitIt will be possible to find conditions of favorable radar
viewing geometry, interface scattering, surface and volume
scattering, and material properties, which may allow us to see
useful reflections of aqueous layers from orbit When strong
internal reflections do occur, they will be identifiable as aqueous
only by contextual inferences drawn from the characteristic
geological context of water habitats When strong internal
reflections do occur, they will be identifiable as aqueous only by
contextual inferences drawn from the characteristic geological
context of water habitats Orbital radar data can be improved by in
situ observations (e.g. magnetotelluric methods)Orbital radar data
can be improved by in situ observations (e.g. magnetotelluric
methods) Methods better than radar sounding for the detection of
Water at planetary scale are not yet identified
Slide 18
Experience of Italian Groups: Marsis The MARSIS instrument is a
low-frequency nadir-looking pulse limited radar sounder and
altimeter with ground penetration capabilities, which uses
synthetic aperture techniques and a secondary receiving antenna to
isolate subsurface reflections.The MARSIS instrument is a
low-frequency nadir-looking pulse limited radar sounder and
altimeter with ground penetration capabilities, which uses
synthetic aperture techniques and a secondary receiving antenna to
isolate subsurface reflections. In Subsurface Sounding Mode the
instrument can transmit any of the following bands: 1.3-2.3 MHz (
1.8 MHz), 2.5-3.5 MHz (3 MHz), 3.5-4.5 MHz ( 4 MHz), 4.5-5.5 MHz (5
MHz).In Subsurface Sounding Mode the instrument can transmit any of
the following bands: 1.3-2.3 MHz ( 1.8 MHz), 2.5-3.5 MHz (3 MHz),
3.5-4.5 MHz ( 4 MHz), 4.5-5.5 MHz (5 MHz). A 1 MHz bandwidth allows
a vertical resolution of 150 m in vacuum, which corresponds to
50-100 m in the subsurface, depending on the E.M. wave propagation
speed in the Martian crust. A 1 MHz bandwidth allows a vertical
resolution of 150 m in vacuum, which corresponds to 50-100 m in the
subsurface, depending on the E.M. wave propagation speed in the
Martian crust. The typical spatial resolution of MARSIS will be 5 9
Km x 15 30 Km in the along track (synthetic aperture) and cross
track (pulse limited footprint) directions respectively.The typical
spatial resolution of MARSIS will be 5 9 Km x 15 30 Km in the along
track (synthetic aperture) and cross track (pulse limited
footprint) directions respectively.
Slide 19
Slide 20
Experience of Italian Groups: Marsis Science Marsis will search
for water up to 5 km below ground.Marsis will search for water up
to 5 km below ground. It will allow to see the top of a liquid zone
somewhere in the upper 2-3 km fairly easily, and down to 5 km or
more, in favorable conditions.It will allow to see the top of a
liquid zone somewhere in the upper 2-3 km fairly easily, and down
to 5 km or more, in favorable conditions. The radio waves will be
reflected at any interface, so Marsis should reveal much about the
composition of the top 5 km of crust.The radio waves will be
reflected at any interface, so Marsis should reveal much about the
composition of the top 5 km of crust.
Slide 21
Transmitter antenna Receiver antenna Smart Lander Error Ellipse
9 Km 5 Km 5.4 Km 6 Km Marsis Sharad Magneto-telluric active and
passive In situ and borehole analysis 300 m
Slide 22
Experience of Italian groups: In situ Electromagnetic
Measurements Augmenting SHARAD results: To measure the complex
resistivity and high frequency permittivity of the first layers of
Martian soil. To evaluate the presence of water and/or ice in the
soil To provide a ground truth for possible radar measurements.
Different Italian groups are developing this kind instruments
(direct complex resistivity measurements, Time-Domain
Electromagnetic Measurements techniques ).Different Italian groups
are developing this kind instruments (direct complex resistivity
measurements, Time-Domain Electromagnetic Measurements techniques
). Laboratory measurements of dielectric constants in different
frequency ranges of Martian Simulants are also developed.Laboratory
measurements of dielectric constants in different frequency ranges
of Martian Simulants are also developed.
Slide 23
SHARAD and MRO MRO ObjectiveInvestigation ObjectiveMeasurement
Requirement I Search for sites showing evidence of aqueous and/or
hydrothermal activity Detailed stratigraphy of key locales to
identify formation processes of geologic features suggesting the
presence of liquid water Vertical resolution: comparable to
observed layer thickness (tens of meters) Horizontal resolution:
comparable to feature size (hundreds of meters to kms) Depth of
penetration: comparable to observed layering thickness (hundreds of
meters) Coverage: local I Explore in detail hundreds of targeted,
globally distributed sites Detailed characterization of the
stratigraphy of surface features to better understand the formation
and evolution of complex terrain Vertical resolution: comparable to
observed layer thickness (tens of meters) Horizontal resolution:
comparable to feature size (hundreds of meters to kms) Depth of
penetration: comparable to observed layering thickness (hundreds of
meters) Coverage: local II Detect the presence of liquid water and
determine the distribution of ground ice in the upper surface,
particularly within the near-surface regolith * Profiling of areas
suspected of hosting hydrothermal or other near- surface reservoirs
of liquid water/brine, mapping of the thickness, extent and
continuity of the layers within the polar deposits Vertical
resolution: comparable to observed layer thickness (tens of meters)
Horizontal resolution: comparable to feature size (hundreds of
meters to kms) Depth of penetration: comparable to observed
layering thickness (hundreds of meters, to kms in the polar
deposits) Coverage: regional
Slide 24
Requirements A radar sounder in the 05 MRO mission has been
studied according to the following high-level requirements:A radar
sounder in the 05 MRO mission has been studied according to the
following high-level requirements: Penetration Depth:300 m 1000
mPenetration Depth:300 m 1000 m Vertical Resolution10-20 mVertical
Resolution10-20 m Horizontal resolution300 m-1000 mHorizontal
resolution300 m-1000 m
Slide 25
Conclusions SHARAD will complement MARSIS : the combined
analysis of these two sounders will permit to extend our knowledge
to Martian subsurface.SHARAD will complement MARSIS : the combined
analysis of these two sounders will permit to extend our knowledge
to Martian subsurface. SHARAD will help the interpretation of MER
results by providing a better characterization of the geologic
context of the landing sites.SHARAD will help the interpretation of
MER results by providing a better characterization of the geologic
context of the landing sites. SHARAD will allow a better selection
of 2007 landing sites, particularly in view of likelihood of
finding subsurface ices.SHARAD will allow a better selection of
2007 landing sites, particularly in view of likelihood of finding
subsurface ices. SHARAD will be a necessary precursor of a
dedicated radar orbital mission (2009 or beyond) SHARAD will be a
necessary precursor of a dedicated radar orbital mission (2009 or
beyond)
Slide 26
Washington Workshop 3,4 Dec 2001 Shallow Radar for Martian
Subsurface Studies: Investigation Overview
Slide 27
SCIENCE OBJECTIVES
Slide 28
Science Floor Profiling of areas suspected of hosting
hydrothermal or other near-surface reservoirs of liquid water/brine
(e.g. weeping layers) will indicate areas of potential interest,
and should effectively inform plans for subsequent surface
investigations designed to follow the water. However, detected
subsurface interfaces will be identifiable as aqueous only by
contextual inferences drawn from the characteristic geological
context of water habitats. vertical resolution: ~10 mvertical
resolution: ~10 m horizontal resolution: hundreds of meters to
kmshorizontal resolution: hundreds of meters to kms penetration
depth: hundreds of meterspenetration depth: hundreds of meters
Slide 29
Science Floor Mapping of the thickness, extent and continuity
of the layers within the polar deposits will provide otherwise
inaccessible information on prior variations in the vertical and
areal extent of the polar deposits, flow in the internal structure
of the caps, existence of peripheral ice deposits that may have
been associated with local discharges of sub-polar or
sub-permafrost groundwater and, if penetration down to the base of
the caps can be achieved, evidence of past or present basal melting
or basal lakes. vertical resolution: ~10 mvertical resolution: ~10
m penetration depth: from few hundred meters to 1 kmpenetration
depth: from few hundred meters to 1 km
Slide 30
INVESTIGATION APPROACH
Slide 31
Requirements From the investigation objectives, the following
measurement requirements have been derived: Vertical resolution:
~10 mVertical resolution: ~10 m Horizontal resolution: hundreds of
meters to kmsHorizontal resolution: hundreds of meters to kms
Penetration: hundreds of meters, up to ~1 kmPenetration: hundreds
of meters, up to ~1 km
Slide 32
Vertical Resolution For a chirp radar (as required in planetary
missions due to the low power available), vertical resolution is a
function of the transmitted bandwidth:For a chirp radar (as
required in planetary missions due to the low power available),
vertical resolution is a function of the transmitted bandwidth:
z=c/(2 B ) In terrestrial dry rocks, values of usually range
between 4 and 10, decreasing for increasing porosity; for water
ice, ~3, for CO 2 ice ~3.In terrestrial dry rocks, values of
usually range between 4 and 10, decreasing for increasing porosity;
for water ice, ~3, for CO 2 ice ~3. To achieve a vertical
resolution of 10 m, a chirp bandwidth between 5 and 10 MHz is
required, depending on the material.To achieve a vertical
resolution of 10 m, a chirp bandwidth between 5 and 10 MHz is
required, depending on the material.
Slide 33
Horizontal Resolution Fresnel zone size:Fresnel zone size: r=
(H /2) Pulse-limited resolution:Pulse-limited resolution: r= (c
H/B) In both cases, a higher frequency provides better resolution,
but improvement is slow (square-root dependence)In both cases, a
higher frequency provides better resolution, but improvement is
slow (square-root dependence) From MARSIS highest frequency of 5
MHz and 1 MHz bandwidth to a 20 MHz radar transmitting a 10 MHz
chirp, the Fresnel zone size decreases by a factor of 2, and the
pulse-limited resolution improves by 3 times.From MARSIS highest
frequency of 5 MHz and 1 MHz bandwidth to a 20 MHz radar
transmitting a 10 MHz chirp, the Fresnel zone size decreases by a
factor of 2, and the pulse-limited resolution improves by 3
times.
Slide 34
Along-Track Resolution Horizontal resolution in the along-track
direction can be improved by means of synthetic aperture
processing, i.e. by the coherent summing of a number of echoes, to
produce the response of an antenna the size of the length traveled
by the spacecraft during the transmission time of the
pulses.Horizontal resolution in the along-track direction can be
improved by means of synthetic aperture processing, i.e. by the
coherent summing of a number of echoes, to produce the response of
an antenna the size of the length traveled by the spacecraft during
the transmission time of the pulses. A high pulse repetition
frequency (PRF) is required to adequately sample the response of
the synthetic aperture: a high data rate is generated, which can be
reduced by on-board processing.A high pulse repetition frequency
(PRF) is required to adequately sample the response of the
synthetic aperture: a high data rate is generated, which can be
reduced by on-board processing. An along-track resolution from 300
m to 1000 m is considered to be compliant with measurement
requirements.An along-track resolution from 300 m to 1000 m is
considered to be compliant with measurement requirements.
Slide 35
Penetration The capability of SHARAD to detect subsurface
interfaces depends on a number of factors, each of which is known
with a different level of uncertainty: Ionosphere (dispersion and
attenuation, Faraday rotation)Ionosphere (dispersion and
attenuation, Faraday rotation) Surface geometry (topography, rock
size distribution)Surface geometry (topography, rock size
distribution) Surface and subsurface composition (dielectric and
magnetic properties)Surface and subsurface composition (dielectric
and magnetic properties) Subsurface structure (layering, porosity,
volumetric scattering)Subsurface structure (layering, porosity,
volumetric scattering)
Slide 36
Characterization of Mars Surface Composition Available data
allow a broad characterization of the Martian surface
compositionAvailable data allow a broad characterization of the
Martian surface composition Thermal Emission Spectrometer (TES)
data from the Mars Global Surveyor (MGS) identify two main surface
spectral signatures from low- albedo regionsThermal Emission
Spectrometer (TES) data from the Mars Global Surveyor (MGS)
identify two main surface spectral signatures from low- albedo
regions The two compositions are a basaltic composition dominated
by plagioclase feldspar and clinopyroxene, and an andesitic
composition dominated by plagioclase feldspar and volcanic glassThe
two compositions are a basaltic composition dominated by
plagioclase feldspar and clinopyroxene, and an andesitic
composition dominated by plagioclase feldspar and volcanic glass
The distribution of the two compositions is split roughly along the
planetary dichotomy: the basaltic composition is confined to older
surfaces, and the more silicic composition is concentrated in the
younger northern plainsThe distribution of the two compositions is
split roughly along the planetary dichotomy: the basaltic
composition is confined to older surfaces, and the more silicic
composition is concentrated in the younger northern plains
Slide 37
Magnetic Properties
Slide 38
Layering Evidence for layering from MOC imagesEvidence for
layering from MOC images Observed layers are tens to hundreds of
meters thickObserved layers are tens to hundreds of meters thick
Origin and extent of observed layering still open to debateOrigin
and extent of observed layering still open to debate Layering as a
limiting factor to penetration is currently neglectedLayering as a
limiting factor to penetration is currently neglected
Characterization of subsurface layering is a scientific target in
itself: more careful modeling will be requiredCharacterization of
subsurface layering is a scientific target in itself: more careful
modeling will be required
Slide 39
Porosity Terrestrial analogues could provide an indication, but
several factors need to be accounted for (differences in the kind
of volcanism, lower gravity, etc.).Terrestrial analogues could
provide an indication, but several factors need to be accounted for
(differences in the kind of volcanism, lower gravity, etc.). A
value of surface porosity of 50 % is consistent with estimates of
the bulk porosity of Martian soil as analysed by the Viking
Landers, but a surface porosity this large requires that the
regolith has undergone a significant degree of weathering.A value
of surface porosity of 50 % is consistent with estimates of the
bulk porosity of Martian soil as analysed by the Viking Landers,
but a surface porosity this large requires that the regolith has
undergone a significant degree of weathering. We set 20 % as a
lower bound for the porosity in our computations: lower values
would hardly produce a significant dielectric contrast between
empty and ice- or water-filled porous material.We set 20 % as a
lower bound for the porosity in our computations: lower values
would hardly produce a significant dielectric contrast between
empty and ice- or water-filled porous material.
Slide 40
Volumetric scattering Since the extinction efficiency of
spheres in the optical region (i.e. when D > ) is approximately
2, we can approximate the fraction of energy lost by a plane wave
crossing an unit volume of the Martian regolith as twice the
cross-section of rocks for which D > in the unit volumeSince the
extinction efficiency of spheres in the optical region (i.e. when D
> ) is approximately 2, we can approximate the fraction of
energy lost by a plane wave crossing an unit volume of the Martian
regolith as twice the cross-section of rocks for which D > in
the unit volume To compute this fraction we need to know the number
of subsurface rocks per unit volume per unit diameter interval,
which is often inferred by assuming that the upper surface layer is
well mixed, that is that the surface area rock coverage can be
equated to the fraction of volume occupied by rocks (Rosiwal's
principle)To compute this fraction we need to know the number of
subsurface rocks per unit volume per unit diameter interval, which
is often inferred by assuming that the upper surface layer is well
mixed, that is that the surface area rock coverage can be equated
to the fraction of volume occupied by rocks (Rosiwal's principle)
Using the surface rock size distribution, for k=30% and =3.3 m (30
MHz wavelength in a medium with =9), F k (D) = 2.610 -2Using the
surface rock size distribution, for k=30% and =3.3 m (30 MHz
wavelength in a medium with =9), F k (D) = 2.610 -2 This translates
into a worst-case cross-section per unit volume of about 3.710
-2This translates into a worst-case cross-section per unit volume
of about 3.710 -2 If k=6% (the mode of the rock abundance
distribution), the worst-case cross-section per unit volume becomes
8.6 10 -4If k=6% (the mode of the rock abundance distribution), the
worst-case cross-section per unit volume becomes 8.6 10 -4
Slide 41
Attenuation in the Subsurface In first approximation,
penetration of an E.M. wave in dry rock is a linear function of
wavelength.In first approximation, penetration of an E.M. wave in
dry rock is a linear function of wavelength. Uncertainties in
subsurface losses can range over orders of magnitude, depending on
dielectric and magnetic properties, layering, porosity, volume
scattering.Uncertainties in subsurface losses can range over orders
of magnitude, depending on dielectric and magnetic properties,
layering, porosity, volume scattering. The transmission of a 10 MHz
bandwidth above day-side plasma frequency requires a central
frequency of at least 10 MHz.The transmission of a 10 MHz bandwidth
above day-side plasma frequency requires a central frequency of at
least 10 MHz. Size and mass requirements for an antenna working at
low frequencies, and the technological complexity for efficient
transmission of a large fractional bandwidth, have determined the
selection of a higher nominal frequency for SHARAD.Size and mass
requirements for an antenna working at low frequencies, and the
technological complexity for efficient transmission of a large
fractional bandwidth, have determined the selection of a higher
nominal frequency for SHARAD. In typical scenarios, adequate
penetration can be achieved for a central frequency of 20 MHz, the
northern hemisphere and the polar caps being favored.In typical
scenarios, adequate penetration can be achieved for a central
frequency of 20 MHz, the northern hemisphere and the polar caps
being favored.
Slide 42
Ionosphere The effect of the Martian ionosphere on the
capability of SHARAD to achieve its goals is minor, if not
negligible.The effect of the Martian ionosphere on the capability
of SHARAD to achieve its goals is minor, if not negligible. In
fact, SHARAD will be operating at frequencies which are at least
twice the peak plasma frequency on the day side, and about an order
of magnitude above the highest values of the plasma frequency
measured on the night side.In fact, SHARAD will be operating at
frequencies which are at least twice the peak plasma frequency on
the day side, and about an order of magnitude above the highest
values of the plasma frequency measured on the night side. At those
frequencies, Faraday rotation should be a minor effect, according
to studies performed for MARSIS (Safaeinili, 2001).At those
frequencies, Faraday rotation should be a minor effect, according
to studies performed for MARSIS (Safaeinili, 2001). As far as the
ionosphere is concerned, SHARAD will thus be equally capable of
operating on the day and night sides of Mars.As far as the
ionosphere is concerned, SHARAD will thus be equally capable of
operating on the day and night sides of Mars.
Slide 43
Rock size distribution at the surface The size-frequency
distribution of rocks on Mars has been determined directly only at
the Viking and Pathfinder landing sitesThe size-frequency
distribution of rocks on Mars has been determined directly only at
the Viking and Pathfinder landing sites The Viking infrared thermal
mapper (IRTM) observations have been used to determine the surface
rock abundance on Mars (Christensen, 1986)The Viking infrared
thermal mapper (IRTM) observations have been used to determine the
surface rock abundance on Mars (Christensen, 1986) Rock abundances
calculated in this fashion indicate an unimodal Poisson
distribution over the planet with minimum abundances of 1 %,
maximum abundances of 30 % and a mode of about 6 %Rock abundances
calculated in this fashion indicate an unimodal Poisson
distribution over the planet with minimum abundances of 1 %,
maximum abundances of 30 % and a mode of about 6 % The Viking
landing sites and the Mars Pathfinder landing site show rock
size-frequency distributions that can be fit by equations of the
form: F k (D) = k exp [-q(k) D], where F k (D) is the cumulative
fractional area covered by rocks of diameter D or larger, k is the
total area covered by all rocks, and q(k) = 1.79 +.152/k (Golombek
and Rapp, 1997)The Viking landing sites and the Mars Pathfinder
landing site show rock size-frequency distributions that can be fit
by equations of the form: F k (D) = k exp [-q(k) D], where F k (D)
is the cumulative fractional area covered by rocks of diameter D or
larger, k is the total area covered by all rocks, and q(k) = 1.79
+.152/k (Golombek and Rapp, 1997)
Slide 44
Rock size distribution at the surface (contd) In the
approximation that electromagnetic scattering is caused only by
(supposedly spherical) rocks whose circumference is equal or
greater than the wavelength, we need to compute the values of F for
D = / , where is the wavelength of the radiationIn the
approximation that electromagnetic scattering is caused only by
(supposedly spherical) rocks whose circumference is equal or
greater than the wavelength, we need to compute the values of F for
D = / , where is the wavelength of the radiation For k=30% and =10
m, F k (D) = 2.010 -4For k=30% and =10 m, F k (D) = 2.010 -4 A
survey of 25,000 high-resolution MOC images (Golombek, 2001)
revealed roughly 25 (~0.1% of the total) with fields of hundred to
thousands of boulders, typically at the base of scarps or around
fresh cratersA survey of 25,000 high-resolution MOC images
(Golombek, 2001) revealed roughly 25 (~0.1% of the total) with
fields of hundred to thousands of boulders, typically at the base
of scarps or around fresh craters
Slide 45
Parameters for Surface Clutter Characterization Surface echoes
from off-nadir portion of the surface can mask subsurface echoes
from nadir if both reach the receiver at the same timeSurface
echoes from off-nadir portion of the surface can mask subsurface
echoes from nadir if both reach the receiver at the same time
Scattering models from natural terrain make use of statistical
parameters, namely the r.m.s. height and the r.m.s. slope, to
describe the topographyScattering models from natural terrain make
use of statistical parameters, namely the r.m.s. height and the
r.m.s. slope, to describe the topography These parameters are
scale-dependent, e.g. the r.m.s. slope depends on the horizontal
distance of the points between which slope is measuredThese
parameters are scale-dependent, e.g. the r.m.s. slope depends on
the horizontal distance of the points between which slope is
measured Scaling of these parameters between the available data
sets (i.e. MOLA altimetry, at 300 m spacing) and the wavelengths of
interest (tens of meters) requires hypotheses on the scaling
behavior of topographic parametersScaling of these parameters
between the available data sets (i.e. MOLA altimetry, at 300 m
spacing) and the wavelengths of interest (tens of meters) requires
hypotheses on the scaling behavior of topographic parameters
Slide 46
Method MOLA topographic profiles, approximately 30 km long,
with points spaced 300 m apartMOLA topographic profiles,
approximately 30 km long, with points spaced 300 m apart Profile is
de-trended to filter out contributions to the topography from
larger structuresProfile is de-trended to filter out contributions
to the topography from larger structures r.m.s height and
point-to-point r.m.s. slope are computed for the profiler.m.s
height and point-to-point r.m.s. slope are computed for the profile
We assume that the topography is self-affine, i.e. its statistical
parameters change with scaleWe assume that the topography is
self-affine, i.e. its statistical parameters change with scale The
scaling behaviour of the topography is described by the Hurst
exponent H: 0 H 1The scaling behaviour of the topography is
described by the Hurst exponent H: 0 H 1
Slide 47
Method (contd) H=0 means stationary profile, while H=1 means
fractal profile (self- similar)H=0 means stationary profile, while
H=1 means fractal profile (self- similar) We make use of the r.m.s.
deviation: x z(x)-z(x+ x)] 2 1/2We make use of the r.m.s.
deviation: x z(x)-z(x+ x)] 2 1/2 For a stationary surface,, is a
constantFor a stationary surface,, is a constant For a self-affine
surface: ( x)= ( x 0 ) ( x/ x 0 ) HFor a self-affine surface: ( x)=
( x 0 ) ( x/ x 0 ) H Fitting a straight line to a logarithmic plot
of as a function of lag distance provides the Hurst exponentFitting
a straight line to a logarithmic plot of as a function of lag
distance provides the Hurst exponent
Slide 48
But is Mars Self-Affine? Mostly yes, at the scales of interest
for this workMostly yes, at the scales of interest for this
work
Slide 49
But is Mars Self-Affine? (contd) Sometimes, however, the
behaviour of the profiles is more complexSometimes, however, the
behaviour of the profiles is more complex
Slide 50
Slide 51
Slide 52
Slide 53
Slide 54
Slide 55
Slide 56
The Scaling Problem
Slide 57
The Scaling Problem (contd)
Slide 58
Clutter as a Function of Wavelength
Slide 59
Clutter Suppression after SAR Processing
Slide 60
Summary Scientific requirements for SHARAD have been
illustrated.Scientific requirements for SHARAD have been
illustrated. A 5-10 MHz bandwidth is necessary to meet vertical and
horizontal resolution requirements.A 5-10 MHz bandwidth is
necessary to meet vertical and horizontal resolution requirements.
In first approximation, penetration is a linear function of
wavelength, but uncertainties in subsurface losses can range over
orders of magnitude.In first approximation, penetration is a linear
function of wavelength, but uncertainties in subsurface losses can
range over orders of magnitude. In typical scenarios, adequate
penetration can be achieved for a central frequency of 20 MHz, the
northern hemisphere and the polar caps being favored.In typical
scenarios, adequate penetration can be achieved for a central
frequency of 20 MHz, the northern hemisphere and the polar caps
being favored. Detailed modeling of clutter is possible, based on
available topographic data: clutter is expected to be weakly
dependent on frequency.Detailed modeling of clutter is possible,
based on available topographic data: clutter is expected to be
weakly dependent on frequency. Over most of Mars, synthetic
aperture processing is required for clutter suppression: for the
nominal design of SHARAD, clutter can be adequately suppressed over
about 40% of the surface of Mars.Over most of Mars, synthetic
aperture processing is required for clutter suppression: for the
nominal design of SHARAD, clutter can be adequately suppressed over
about 40% of the surface of Mars.
Slide 61
OBSERVATIONAL GEOMETRY
Slide 62
Science Observations Science observations will begin with the
deployment of the antenna, which will take place only after the end
of aerobraking; after deployment, the spacecraft can only perform
limited accelerations.Science observations will begin with the
deployment of the antenna, which will take place only after the end
of aerobraking; after deployment, the spacecraft can only perform
limited accelerations. During instrument data collection, S/C shall
always be oriented such that the antenna dipole is orthogonal to
the nadir axis: the antenna axis needs to be positioned within 10
degrees of desired nadir-looking direction (TBC).During instrument
data collection, S/C shall always be oriented such that the antenna
dipole is orthogonal to the nadir axis: the antenna axis needs to
be positioned within 10 degrees of desired nadir-looking direction
(TBC). If the orientation of the solar panels will be more than TBD
degrees from the direction orthogonal to the antenna axis, Sharad
measurements could be jeopardized.If the orientation of the solar
panels will be more than TBD degrees from the direction orthogonal
to the antenna axis, Sharad measurements could be jeopardized.
Slide 63
Observing Geometry SHARAD is a nadir looking radar sounder with
synthetic aperture capabilities
Slide 64
Observation Planning According to its system characteristics,
and mainly to its carrier frequency, SHARAD is in principle able to
operate at any time in the orbit, no matter of the sun illumination
conditions.According to its system characteristics, and mainly to
its carrier frequency, SHARAD is in principle able to operate at
any time in the orbit, no matter of the sun illumination
conditions. The SHARAD Science Team supposes that the actual
science observation planning should be the result of a negotiation
taking into account specific observation opportunities (if any) and
the relevant instrument priorities.The SHARAD Science Team supposes
that the actual science observation planning should be the result
of a negotiation taking into account specific observation
opportunities (if any) and the relevant instrument priorities.
Slide 65
Observing Modes Instrument Modes shall belong to any of the
following two classes:Instrument Modes shall belong to any of the
following two classes: Support Modes Support Modes Operation Modes
Operation Modes The Support Modes are used for warm-up, to keep the
instrument ready to operate with reduced power consumption, and for
auxiliary tasks such as failure recovery, SW patching and
troubleshooting.The Support Modes are used for warm-up, to keep the
instrument ready to operate with reduced power consumption, and for
auxiliary tasks such as failure recovery, SW patching and
troubleshooting. The Operation Modes are those in which the
instrument performs its nominal science data acquisitions and may
also include calibration modes.The Operation Modes are those in
which the instrument performs its nominal science data acquisitions
and may also include calibration modes.
Slide 66
Observing Modes SUPPORT MODESSUPPORT MODES ModeRDSTXNotes
DESRFES OffOffOffOff Spacecraft Control Request Check/INITOnOffOff
StandbyOnOffOff DES Control Warm-Up1OnOnOff Warm-Up2OnOnOn DES
Control No RF Radiation IdleOnOffOff Emergency Recovery Mode
Slide 67
Observing Modes OPERATION MODESOPERATION MODES ModeRDSTXNotes
DESRFES Sub-surface Low OnOnOn Doppler processing is completed on
ground to provide low horizontal resolution and narrow FOV
Sub-surface High OnOnOn Doppler processing is completed on ground
to provide high horizontal resolution and high FOV Raw Data OnOnOn
for very limited data takes the instrument is able to provide in
the science data telemetry raw data without any preliminary
processing CalibrationOnOnOn Raw Calibration Data Receive Only
OnOnOff Passive Measurements. Allowed also during cruising phase
with antenna folded (TBV)
Slide 68
Observing Modes Data Rate Data Rate Operation Mode Data Rate
Subsurface Sounding Low 0.35 Mbps Subsurface Sounding High 1.4 Mbps
Raw Data 14.0 Mbps Receive Only TBD CalibrationTBD
Slide 69
ANALYSIS TECHNIQUES
Slide 70
Data Processing Operate on level 2 data from archive Operate on
level 2 data from archive Calibration and other corrections are
considered already applied to the data Calibration and other
corrections are considered already applied to the data Aim at
extracting high level products, directly usable for science
interpretation Aim at extracting high level products, directly
usable for science interpretation Joint processing of multiple
radar sweeps: Joint processing of multiple radar sweeps: - echoes
collected along an orbit (or part) - echoes from multiple
overlapping or close orbits - echoes collected at multiple
frequencies in the orbit (if applicable) Joint processing of data
collected from MARSIS and other instruments (TBC)Joint processing
of data collected from MARSIS and other instruments (TBC)
Slide 71
Joint Processing of a Sequence of Echoes Fitting a parametric
subsurface model possible models: - linear - constant radius of
curvature - polynomial
Slide 72
Statistically based data processing schemes - use joint
distribution of the sequence of echoes - obtain statistically
optimized estimators for subsurface model parameters - use
hypotheses test approach for assessing detection of subsurface
layers - use hypotheses test approach for assessing detection of
subsurface layers - derive confidence parameters on the detection
and on the accuracy of estimated parameters
Slide 73
Removal of topographic effects - required to retrieve a
meaningful shape for hydrological/thermal interfaces - height
profile derived from surface tracking and s/c ephemeris -
topography also derived from MOLA - joint usage of the two for
increased reliability
Slide 74
Joint processing of the echoes from overlapping or close orbits
Allows the joint processing of multiple orbits with the same or
different frequencies Use of 2D parametric subsurface model to
implement best fitting algorithms
Slide 75
Joint processing of the echoes at multiple frequencies - same
subsurface geometric model - possibly different interface
reflectivity and propagation velocity Performance improvement at
multiple frequencies:Performance improvement at multiple
frequencies: - better estimation of subsurface shape (more
information on the subsurface model at multiple frequencies) (more
information on the subsurface model at multiple frequencies) -
estimation of parameters related to the dielectric properties of
the layers
Slide 76
Data processing at polar regions Martian polar layered
deposits: sedimentary deposits of ice and dust. Identification of
layered structure: - estimation of layer thickness - estimation of
layer composition - analysis of layers continuity over large
area
Slide 77
Data processing at polar regions Investigation of morphology
under the polar caps: unknown morphological structure under the
poles unknown morphological structure under the poles unknown
composition of the layers under the poles unknown composition of
the layers under the poles possible deep penetration in dry ice
with low frequency possible deep penetration in dry ice with low
frequency
Slide 78
Summary of data processing techniques Water distribution in the
upper portions of the crust of Mars Multiple hypotheses testing to
be investigated by processing subsurface data with ad-hoc developed
algorithms based on different selected models. Three different
possible models: no water at SHARAD penetration depth; water
distribution follows exactly the surface profile; water
distribution follows a gravitational geoid Mars polar region Two
aspects can be considered: topographic mapping of the region below
the Mars polar caps; mapping of the layered structures of the polar
regions; To be studied by processing subsurface data arising from
all the different orbits eventually covering the same region Also:
joint processing of MARSIS data in different modes and SHARAD
data(TBC) joint processing of radar data & other instruments
(data fusion)
Slide 79
Washington Workshop 3,4 Dec 2001 Shallow Radar for Martian
Subsurface Studies: Instrument Overview
Slide 80
SHARAD Concept SHARAD system is conceived as a dual frequency
shallow radar providing measurements at the centre frequencies 17.5
and 22.5 Mhz. At these centre frequencies the radar will trasmit
two radar pulses shortly separated in time within the same radar
sweep. Each radar pulse is linear frequency modulated over a 5 Mhz
bandwidth to provide 30 meters resolution in free space. Echoes
from the two bands (15 - 20 Mhz) (20 - 25 Mhz) are treated
independently on board. On ground, echoes are processed still
independently through SAR based techniques to enhance the azimuth
resolution and therefore clutter reduction Possible stepped chirp
technique for finer range resolution.
Slide 81
Instrument Requirements RequirementCapability Vertical
resolution 15 m (in a material with dielectric constant equal to 5)
Horizontal resolution 300-1000 m along track (after processing)
1500-8000 m across track (depending on altitude, topography and
vertical resolution) Depth of penetration 100s of meter (depending
on subsurface structure and composition), up to 1 km To meet these
objectives, an HF nadir looking synthetic aperture radar will be
designed, of relatively large bandwidth to meet the range
resolution requirement. Synthetic aperture processing allows
improvement of the along track spatial resolution and,
consequently, also reduction of the off-nadir ground clutter
echo.
Slide 82
SHARAD System Preliminary Parameters Antenna: half wave
dipole~7 m length (tip-to-tip) Centre Frequencies:17.5 & 22.5
MHz Radiated Peak Power: 10 W Pulse Length:300 s Pulse Bandwidth:5
MHz Pulse Repetition Frequency: ~150 Hz Vertical Swath Range:40 s
(6 Km - free space)
Slide 83
SHARAD Hierarchical Configuration
Slide 84
SHARAD S/S Description SHARAD instrument is based on 3 major
subsystems: Antenna S/S: the baseline is a dipole antenna. Few
antenna options are currently under investigation. In the simplest
case the dipole should size 7 meters tip-to-tip and 3.8 cm
diameter. This solution requires a matching network in order to
optimize the radiation efficiency Tx S/S: A single large bandwidth
transmitter is envisaged operating in the bandwidth 15 - 25 Mhz.
With given performance of Dipole Antenna, the Tx S/S shall be
designed to ensure at least 10 Watts of radiated peak power.
Slide 85
SHARAD S/S Description RDS: The RadioFrequency Receiver (Rx)
and Digital (DES) units of the radar, resembling the MARSIS
architecture, are enveloped in the same box. More specifically the
implemented functions of RDS are: Command & Control Data
Acquisition and Processing Data Interface Radar Pulse Generation
and Instrument Timing Radar Receiver DC/DC Converters for Digital
and Rx RadioFrequency Part. Radar Chirp Generation is based on
Direct Digital Synthesis (DDS) technique. Synthesis is accomplished
directly at the radar frequency. Bands up to 10 MHz wide can be
generated.
Slide 86
SHARAD S/S Description Analog receiver is of deramping type
with low noise amplifier followed by a deramping mixer, band pass
filtering and final stage with gain regulation to adjust the
receiver dynamics (AGC). Rx signal is digitally filtered and
converted to video in order to synthesize the I/Q signal
components. Rx signal is pre-processed on board with a limited
amount of coherent processing to reduce instrument data rate.
Pre-processed echoes are transferred on ground for range
compression and fully focused SAR processing to enhance azimuth
resolution.
Slide 87
Options The following items are subject to trade-off activity:
System Level: Inclusion of an additional lower frequency channel
(10 - 15 Mhz range) Subsystem level: Antenna Receiver
Slide 88
Lower Frequency Channel Inclusion of a lower frequency channel
(10 - 15 Mhz) may imply: Cons dedicated transmitter longer dipole
antenna dedicated matching network Pros Major flexibility of the
experiment Better estimate of the target dielectric
characteristics
Slide 89
Antenna Options Antenna trade-off is aimed to: Improve as much
as possible on the entire band (15-25 MHz) the antenna efficiency
allow the possibility of improving the system bandwidth for the
possible introduction of an additional radar channel at a lower
frequency (range 10 - 15 Mhz) while keeping at the minimum the
changes respect to baseline (7 meters tip-to-tip antenna)
Slide 90
Antenna Options l Single dipole 7.00 mt. Long _Require a
matching network _Easy and light structure l Single dipole 9.6 mt.
long, Diam. 3.8 cm. _ Balun required _ Easy and light structure X Y
Z 7.0 mt. X Y Z 9.6 mt.
Slide 91
Receiver Options Receiver baseline foresees the use of a
downconverting mixer for deramping operation. As an option, it is
considered the possibility of keeping the receiver the simplest
possible while transferring the band filtering issue into the
digital section, avoiding the mixer, the narrow band filtering and
using instead a large A/D sampling frequency for direct sampling on
carrier. Advantages: extremely simple receiver design Drawbacks:
digital processing front end (potentially based on FPGA design) to
be included in the DES architecture
Slide 92
H/W & S/W Heritage Assembly Design Heritage (%) Flight
Heritage (%) Antenna It is presently planned to procure the antenna
by a well proven manufacturer in order to minimize the risk
Transmitter 70 30 Receiver 70 30 Digital SS 100 70 70
Slide 93
Risk (Top Four) ItemMitigation Plan Transmitter (schedule) ITAR
Calibration Early design and test. Fast MOU finalization. In depth
definition of ground characterisation
Slide 94
Concerns EM interaction between SHARAD antenna and S/C (solar
panels, HGA)EM interaction between SHARAD antenna and S/C (solar
panels, HGA)
Slide 95
BASELINE SCHEMATICS
Slide 96
Block Diagram DCG Timing A/D & I/Q Synthesis Echo Processor
Data I/F Cmd/Crtl LNA T/R Switch Impedence Matching Net Tx Amp BPF
G Div Stalo Power Distribution S/C Data & Cmd Bus AntTx
RDS
Slide 97
S/W Block Diagram SHARAD SW Architecture will be based on the
MARSIS SW archictecture which is build on a base HW configuration
of 3 DSP (21020): one for C 2 (Master DSP) and 2 Slave Processing
DSPs Virtuoso RTOS (Run Time Operative System) is a commercial
Operative System Tool
Slide 98
Mechanical Configuration Baseline: Antenna (Ant) Transmitter
(Tx) RadioFrequency and Digital (RDS) Physical Dimensions (CBE)
RDS==> 22 x 25 x 20 cm TX==> 45 X 15 X 10 cm Antenna==> 45
x 25 x 10 cm (Stowed configuration)
Slide 99
Mechanical Configuration RDS will be designed using the already
qualified mechanical design of MARSIS which allows a modular
approach. For the transmitter a separate box is foreseen. Antenna
mechanical frame is strongly dependent on final
technology/manufacturer selection RDS mechanical frame
Slide 100
Mass And Power Current Best Estimates Assembly Mass (Kg)
Uncertainty Power (w) Uncertainty Antenna2.0 30 % - 0.6 Kg -
Transmitter3.0 30 % - 0.9 Kg 13 30 % - 3.9 W Cabling0.75 20 % -
0.15 Kg TBC pending on S/S harness routing definition - RDS (Rx
& Digital Subsystem) 6.0 10 % - 0.6 Kg 39 10 % - 3.9 W
TOTAL11.75 2.25 Kg 52 7.8 W
Slide 101
Power By Different Operational Modes (1) Replacement heaters
are heaters required to be turned on when the instrument is turned
off (like at launch and during cruise). The heater(s) are there to
assure that the instrument stays within acceptable temperature
limits. Mode Operational Power Replacement Heaters power (1) Off
010 W Check/Init - Stdby - Idle 25 W WarmUp1 WarmUp2 Operation
Modes 30 W 35 W 52 W 10 W
Slide 102
Data Handling Summary Data Mode Data Volume (per orbit, 30 min.
nominal operations) Subsurface Sounding Low 0.630 Gbit Subsurface
Sounding High 2.5 Gbit Raw Data 0.84 Gbit for each minute of
operation Receive Only TBC CalibrationTBC
Slide 103
Processing Characteristics SHARAD is presently planning to
pre-process the return echoes on board, exclusively using its own
Digital subsystem resourcesSHARAD is presently planning to
pre-process the return echoes on board, exclusively using its own
Digital subsystem resources The on-board processing will be
possibly limited to some coherent processing in order to meet the
S/C requirements in terms of produced data rate and volume and, at
the same time, to maintain the highest possible flexibility in the
ground processingThe on-board processing will be possibly limited
to some coherent processing in order to meet the S/C requirements
in terms of produced data rate and volume and, at the same time, to
maintain the highest possible flexibility in the ground processing
No data compression processing is at this moment planned for the
telemetry data produced by SHARADNo data compression processing is
at this moment planned for the telemetry data produced by
SHARAD
Slide 104
EMI Characterization/Validation
Slide 105
The SHARAD special requirements are that broadband EMI
disturbances must be lower than the galactic noise received by the
antenna, that is 12 dB V/m (TBC) measured on a bandwidth of 30 KHz
(TBC) in the range 10-30 MHz. Narrow band disturbance (spike)
laying within the SHARAD bandwidth must have a level lower than TBD
dB. The level of out of band spikes shall be lower than TBD dBThe
SHARAD special requirements are that broadband EMI disturbances
must be lower than the galactic noise received by the antenna, that
is 12 dB V/m (TBC) measured on a bandwidth of 30 KHz (TBC) in the
range 10-30 MHz. Narrow band disturbance (spike) laying within the
SHARAD bandwidth must have a level lower than TBD dB. The level of
out of band spikes shall be lower than TBD dB The field strength
produced by SHARAD is under evaluation and will be provided as soon
as possibleThe field strength produced by SHARAD is under
evaluation and will be provided as soon as possible
Slide 106
Calibration Requirements
Slide 107
Calibration requirements The objective of the calibration is to
determine the expected uncertainty in the geophysical
characteristics of the surface and subsurface as measured by
SHARAD.The objective of the calibration is to determine the
expected uncertainty in the geophysical characteristics of the
surface and subsurface as measured by SHARAD. The calibration of
SHARAD is similar to the calibration of a SAR system but has the
added complexity of the matching between the sounder electronics
with the antenna.The calibration of SHARAD is similar to the
calibration of a SAR system but has the added complexity of the
matching between the sounder electronics with the antenna. The
calibration of the electronics system gain will follow standard
procedures and will be performed on ground.The calibration of the
electronics system gain will follow standard procedures and will be
performed on ground. SHARAD is presently planning to perform also
the TX-Antenna calibration on ground. In any case this calibration
will be performed also while in orbit around Mars, using the echoes
received from very flat surfaces according to a TBD procedure every
TBD orbits.SHARAD is presently planning to perform also the
TX-Antenna calibration on ground. In any case this calibration will
be performed also while in orbit around Mars, using the echoes
received from very flat surfaces according to a TBD procedure every
TBD orbits.
Slide 108
SPACECRAFT ACCOMODATION ISSUES
Slide 109
Antenna and TX Placement The present baseline for SHARAD is to
have all the subsystems assembled in three boxes: RX+DES, TX and
Ant. The physical dimensions will be:The present baseline for
SHARAD is to have all the subsystems assembled in three boxes:
RX+DES, TX and Ant. The physical dimensions will be: RX+DES
22x25x20 cm (TBC) RX+DES 22x25x20 cm (TBC) TX 45x15x10 cm (TBC) TX
45x15x10 cm (TBC) Antenna (stowed) 45x25x10 cm (TBC) Antenna
(stowed) 45x25x10 cm (TBC) The antenna should be mounted on a wall
of the S/C and such that its electrical axis (that is its booms) is
perpendicular to the solar panels in order to avoid any EM coupling
into and reflection from solar arrays. As a matter of fact this
causes an unintended directionality to the antenna radiation
pattern which could severely degrade the experiment performance and
could also worsen EMI problem for spacecraft.The antenna should be
mounted on a wall of the S/C and such that its electrical axis
(that is its booms) is perpendicular to the solar panels in order
to avoid any EM coupling into and reflection from solar arrays. As
a matter of fact this causes an unintended directionality to the
antenna radiation pattern which could severely degrade the
experiment performance and could also worsen EMI problem for
spacecraft. The TX box should be mounted as much as possible close
to the antenna box in order to minimize cable loss and impedance
matching problems.The TX box should be mounted as much as possible
close to the antenna box in order to minimize cable loss and
impedance matching problems.
Slide 110
Washington Workshop 3,4 Dec 2001 Shallow Radar for Martian
Subsurface Studies: Management Plans
Slide 111
Overview In-House vs. Out-of-House The INFOCOM Department, the
Team Leader institution, does not plan to develop the instrument in
its own facilities. All SHARAD H/W and S/W will be developed by the
Industrial Partner(s) selected by ASI Major Partners ALS + other
major subcontractors (TBC) I, T, & C Location ALS (TBC) Outside
Contributions TBC Foreign Involvement NA
Slide 112
H/W Deliverables (to MRO) ItemDate Payload Fit Check Template
(Structural Model SM) December 02 Payload Interface Simulator
(Interface Engineering Model IEM) February 03 EM and GSE September
03 FM and GSE March 04
Slide 113
S/W and Data Deliverables (to MRO) EVENT OR DELIVERABLE ITEM
DESCRIPTION EVENT OR DUE DATE Telemetry calibration data
PreliminaryPreliminary FinalFinal Definition of instrument
telemetry, calibration curves, algorithms and tolerances ICDRIDR
Flight sequences PreliminaryPreliminary FinalFinal Definition of
instrument sequences for use in system test to include all
instrument operations modes ICDRIDR Analytic thermal model
PreliminaryPreliminary FinalFinal Used to develop the system-level
thermal design and support the thermal vacuum test ICDRIDR Initial
flight S/W and supporting documentation Provide the initial FSW
load to support OTB I&T IDR Initial ground S/W and supporting
documentation Provide the initial ground S/W to support system
tests IDR Final S/W baseline and supporting documentation Provide
the final FSW load to support flight ATLO IORR Final ground S/W and
supporting documentation Provide the final ground operations and
data analysis S/W to support launch ORR -1month
Slide 114
Documentation Deliverables to MRO (1) DocumentDescription Event
or Due Date TMCO Technical, Management and Cost package 26/11/2001
ISRD Investigation Science Requirement Document Draft 17/12/2001
Final 24/01/2002 EIP Experiment Implementation Plan January 2002
FRD Functional Requirement Document February 2002 Flight rules and
constraint PreliminaryPreliminary FinalFinal Defifnition of
instrument operation constraints and requirements IPDRICDR Command
telemetry data PreliminaryPreliminary FinalFinal Dictionary of
instrument commands and operation modes. Definition of instrument
telemetry parameters ICDRIDR
Slide 115
Documentation Deliverables to MRO (2) ICDs
PreliminaryPreliminary FinalFinal Inputs to Interface Control
Documents PDRCDR GDS/MOS requirements PreliminaryPreliminary
FinalFinal Inputs to Ground Data System and Mission Operations
System Requirement Documents IDR ORR 1month Payload handling
requirements PreliminaryPreliminary FinalFinal Payload Handling
Requirements list ICDR IDR 1 month Unit history log-books IDR End
Item Data Package (EIDP) IDR
Slide 116
Receivables List (From MRO) ItemDate S/C Simulator October
2002
Slide 117
Investigation Communications Plan Internal to Team All
documentation for internal use will be made available to Team
Members by means of a password-protected web page hosted at the
Team Leader institution.All documentation for internal use will be
made available to Team Members by means of a password-protected web
page hosted at the Team Leader institution. External (with Project
Office) All documentation for external use will be made available
to MRO Project Office by means of a password-protected FTP site
hosted at the Team Leader institution.All documentation for
external use will be made available to MRO Project Office by means
of a password-protected FTP site hosted at the Team Leader
institution. All the documents will be available on the FTP site
only after the ASI PO approvalAll the documents will be available
on the FTP site only after the ASI PO approval
Slide 118
Workforce Profile: Science Team (1) Team Leader: Roberto Seu.
He received the doctoral degree in electronic engineering and the
Ph.D. on Communication and Information Theory at University of Rome
La Sapienza, where he is assistant professor at INFOCOM Dept. His
main research activities are mainly related to active microwave
remote sensing. He is member of the Cassini Radar Science Team,
Co-I of the Rosetta/CONSERT experiment and Deputy PI of the Mars
Express/MARSIS experiment. Experiment Manager: Arturo Masdea. He
has had 35 years of experience in electronic engineering at Alenia
S.p.A. Specialist in electronic product, system design and project
management in defence and space applications (Radar, Lidar,
Missile, EWS and EO systems). Author of international patents and
technical reports. During last five years was participating on the
activity of INFO-COM dept. This participating activity was mainly
performed on seminar, on remote sensing (active and passive) by EO
system and on system sounding analysis and design of Rx and Tx for
the Rosetta mission. Team Member: Daniela Biccari. She received the
doctoral degree in electronic engineering from the University of
Rome "La Sapienza" in 2000. She is now attending the 2nd year of
the PhD course on Remote Sensing at the same university, INFOCOM
Dpt. She is Co-I of the Mars Express/MARSIS experiment.
Slide 119
Workforce Profile: Science Team (2) Team Member: Costanzo
Federico. He is associate professor of geophysics at University of
Perugia (Italy). He is Co-Investigator in experiments on planetary
NASA and ESA missions. Member of ESA Peer Committees. He has
published more than 80 pubblications in referred journals.
Scientific activities include modelling of evolution of Earth and
terrestrial-like planet interiors using different data types :
seismic, gravimetric and geological observations.Team Member:
Costanzo Federico. He is associate professor of geophysics at
University of Perugia (Italy). He is Co-Investigator in experiments
on planetary NASA and ESA missions. Member of ESA Peer Committees.
He has published more than 80 pubblications in referred journals.
Scientific activities include modelling of evolution of Earth and
terrestrial-like planet interiors using different data types :
seismic, gravimetric and geological observations. Team Member:
Vittorio Formisano. He graduated in Physics cum laude in Rome in
1965. Researcher at LPS-CNR (now IFSI). Visiting Scientist at
M.I.T. (for two years) and at UCLA (six months). He organized the
international conference: Le Prime misure di Pioneer 10 a Giove
(1974, Frascati, ESRIN ). He is the Italian responsible person for
the CIS experiment on board CLUSTER. He is PI of the OPERA
experiment for INTERBIOL. He is PI of the PFS experiment for Mars
96 and for Mars Express. He is the responsible person for the
Italian channel of the Omega experiment for per Mars 96. He is
Co.I. of Omega for Mars Express, of VIMS for Cassini, of PANCAM for
Netlander. Over 180 publications on refereed journalsTeam Member:
Vittorio Formisano. He graduated in Physics cum laude in Rome in
1965. Researcher at LPS-CNR (now IFSI). Visiting Scientist at
M.I.T. (for two years) and at UCLA (six months). He organized the
international conference: Le Prime misure di Pioneer 10 a Giove
(1974, Frascati, ESRIN ). He is the Italian responsible person for
the CIS experiment on board CLUSTER. He is PI of the OPERA
experiment for INTERBIOL. He is PI of the PFS experiment for Mars
96 and for Mars Express. He is the responsible person for the
Italian channel of the Omega experiment for per Mars 96. He is
Co.I. of Omega for Mars Express, of VIMS for Cassini, of PANCAM for
Netlander. Over 180 publications on refereed journals
Slide 120
Workforce Profile: Science Team (3) Team Member: Pierfrancesco
Lombardo. He got the doctoral degree in Electronic Engineering and
the Ph.D. at the University of Rome "La Sapienza". He has been
research associate at the University of Birmingham (UK) and
Research Scientist at Syracuse University (NY-USA). In 1996 he
joined as a Research Scientist the University of Rome La Sapienza,
where he is Associate Professor since 1998. Dr. Lombardo is
involved in scientific research projects funded by the Italian
Space Agency for the development of signal processing techniques
for multiparametric SAR images. He is also involved in research
projects on data fusion and on other projects on advanced radar
detection. His main interests are in radar adaptive signal
processing, radar clutter modeling, radar coherent detection, SAR
processing and radio-localization systems.Team Member:
Pierfrancesco Lombardo. He got the doctoral degree in Electronic
Engineering and the Ph.D. at the University of Rome "La Sapienza".
He has been research associate at the University of Birmingham (UK)
and Research Scientist at Syracuse University (NY-USA). In 1996 he
joined as a Research Scientist the University of Rome La Sapienza,
where he is Associate Professor since 1998. Dr. Lombardo is
involved in scientific research projects funded by the Italian
Space Agency for the development of signal processing techniques
for multiparametric SAR images. He is also involved in research
projects on data fusion and on other projects on advanced radar
detection. His main interests are in radar adaptive signal
processing, radar clutter modeling, radar coherent detection, SAR
processing and radio-localization systems. Team Member: Lucia
Marinangeli. She got the degree in Geology at the Universit di
Bologna in 1992 with a thesis on Geochemistry and Sedimentology of
the recent deposits of the Northern Adriatic Sea. In 1998 she
completed the Ph.D. program working on Geological and statigraphic
evolution of the Ishtar Terra highland on Venus. Her current
research interests regard the reconstruction of paleoclimate
changes from paleofluvial and paleolacustrine morphologies on Mars
and in arid lands on Earth. Since 1999 she also is PI for the
development of a micro x-ray diffractometer for the Italian package
of future Martian landers (ASI project).Team Member: Lucia
Marinangeli. She got the degree in Geology at the Universit di
Bologna in 1992 with a thesis on Geochemistry and Sedimentology of
the recent deposits of the Northern Adriatic Sea. In 1998 she
completed the Ph.D. program working on Geological and statigraphic
evolution of the Ishtar Terra highland on Venus. Her current
research interests regard the reconstruction of paleoclimate
changes from paleofluvial and paleolacustrine morphologies on Mars
and in arid lands on Earth. Since 1999 she also is PI for the
development of a micro x-ray diffractometer for the Italian package
of future Martian landers (ASI project).
Slide 121
Workforce Profile: Science Team (4) Team Member: Roberto
Orosei. He graduated in Astronomy in 1992 with full marks cum
laude. He was awarded an ESA Research Fellowship at ESTEC from
February 1994 to January 1996. He completed a PhD in Remote Sensing
in 1999. He is involved in several space experiments, and is
Co-investigator of MARSIS (MArs Radar Subsurface and Ionosphere
Sounder) for ESA's Mars Express mission. His scientific activities
include the modeling and simulation of radar wave propagation in
planetary environments.Team Member: Roberto Orosei. He graduated in
Astronomy in 1992 with full marks cum laude. He was awarded an ESA
Research Fellowship at ESTEC from February 1994 to January 1996. He
completed a PhD in Remote Sensing in 1999. He is involved in
several space experiments, and is Co-investigator of MARSIS (MArs
Radar Subsurface and Ionosphere Sounder) for ESA's Mars Express
mission. His scientific activities include the modeling and
simulation of radar wave propagation in planetary environments.
Team Member: Giovanni Picardi. He is full professor of Remote
Sensing Systems at INFO-COM Dpt, University of Rome "La Sapienza".
He has been involved in several projects for the European Space
Agency (ESA) and the Italian Space Agency (ASI). He has been member
of the Science Team for the definition of the ROSETTA, MORO (Moon
Orbiting Observatory) and INTERMARSNET missions. He is presently
the PI of the Mars Express/MARSIS experiment, member of the Cassini
Radar Science Team and Co-I of the Rosetta/CONSERT experiment. His
main activity is in radar design for civil and military
applications and remote sensing. He is the author of several books
and of more than 130 publications, including conferences,
concerning radar signal processing and system analysis.Team Member:
Giovanni Picardi. He is full professor of Remote Sensing Systems at
INFO-COM Dpt, University of Rome "La Sapienza". He has been
involved in several projects for the European Space Agency (ESA)
and the Italian Space Agency (ASI). He has been member of the
Science Team for the definition of the ROSETTA, MORO (Moon Orbiting
Observatory) and INTERMARSNET missions. He is presently the PI of
the Mars Express/MARSIS experiment, member of the Cassini Radar
Science Team and Co-I of the Rosetta/CONSERT experiment. His main
activity is in radar design for civil and military applications and
remote sensing. He is the author of several books and of more than
130 publications, including conferences, concerning radar signal
processing and system analysis.
Slide 122
Workforce Profile: Science Team (5) Team Member: Sebastiano B.
Serpico. He is an Associate Professor of Telecommunications at the
University of Genoa. His current research interests are related to
the application of signal processing and pattern recognition to
remotely sensed images. From 1995 to 1998, Dr. Serpico was the Head
of the Signal Processing and Telecommunications Research Group
(SP&T) of DIBE; he is currently the Head of the SP&T labs.
He is author (or co-author) of about 150 scientific publications,
including journals and conferences. He is an associate editor of
the IEEE Transactions on Geoscience and Remote Sensing.Team Member:
Sebastiano B. Serpico. He is an Associate Professor of
Telecommunications at the University of Genoa. His current research
interests are related to the application of signal processing and
pattern recognition to remotely sensed images. From 1995 to 1998,
Dr. Serpico was the Head of the Signal Processing and
Telecommunications Research Group (SP&T) of DIBE; he is
currently the Head of the SP&T labs. He is author (or
co-author) of about 150 scientific publications, including journals
and conferences. He is an associate editor of the IEEE Transactions
on Geoscience and Remote Sensing.
Slide 123
Workforce Profile: industrial partner ASI has issued an
industrial contract to Alenia Spazio for the study phase and is
planning to issue to ALS the contract for the DD&V
Slide 124
SCIENCE TEAM AND INSTRUMENT TEAM
Slide 125
Roles And Responsibilities AreaWho MRO Contacts Investigation
Management R. Seu R. Zurek Experiment Project Office E. Flamini R.
DePaula/J. Graf Project Engineer Interface A. Masdea J. Duxbury
Instrument Development G. Braconi J. Duxbury Mission Operations
Uplink Planning Instrument Health & Safety Signal Processing
Science Data Processing ALS (Development) + TBD D. Biccari P.
Lombardo + ASDC Ben Jai Data Analysis Science Analysis Quick Look
and Public Outreach Data Archival C. Federico L. Marinangeli R.
Orosei + ASDC Ben Jai Michele Viotti Ben Jai
Slide 126
Roles And Responsibilities (continued) AreaWho MRO Contacts
Mission Assurance E. Marchetti ASI G. Montanari Tbc -ALS P. Barela
Ground Data System Development/ Mission Operations R. Seu / R.
Orosei Ben Jai
Slide 127
Organization Chart ASI Project Office Enrico Flamini Angioletta
Coradini Sylvie Espinasse Team Leader Roberto Seu U. Roma, Italy
Co-Team Leader R. Phillips, Washington Univ., St. Louis, MO, USA
Science Team D. Biccari, U. Roma, Italy C. Federico, U. Perugia,
Italy V. Formisano, IFSI/CNR, Roma, Italy P. Lombardo, U. Roma,
Italy L. Marinangeli, IRSPS, Pescara, Italy R. Orosei, IAS/CNR,
Rome, Italy G. Picardi, U. Roma, Italy S.B. Serpico, U. Genova,
Italy J. Plaut, JPL, Pasadena, CA, USA B. Campbell, Smithsonian
Inst., Washington DC, USA Experiment Manager Arturo Masdea U. Roma,
Italy Industry PM & IM G. Braconi & C. Zelli Italy System
Design Italy Digital SS Italy RF SS Italy Antenna SS Italy System
AIV/AIT Italy
Slide 128
Work Breakdown Structure (1) SHARAD WBS SCIENCE MANAGEMENT
[Italy/USA] SYSTEM ENGINEERING Italy PRODUCT ASSURANCE Italy
ANTENNAS Italy HF SECTION (HFS) Italy DIGITAL SECTION (DS) Italy
AIT / GSE Italy
Slide 129
Work Breakdown Structure (2) INTERFACE SCIENCE REQUIREMENT
SCIENTIFIC MODELLING SCIENCE DATABASE\ SCIENTIFIC COST ANALYSIS
SYNERGY WITH OTHER EXPREIMENTS SOFTWARE SIMULATION SCIENCE
MANAGEMENT [ITALY/USA ] ELECTRICAL THERMO - MEC. SYSTEM ENGINEERING
I/F's & BUDGETS ANALYSIS AIV ON - GROUND ALGORITHMS FLIGHT
OPERATIONS SYSTEM ENGINEERING Italy
Slide 130
Work Breakdown Structure (3) QUALITY ASSURANCE PARTS MATERIAL
& PROCESS RELIABILITY & MAINTEN. SAFETY PRODUCT ASSURANCE
Italy ELECTRICAL THERMO MECHANICAL THERMAL DEPLOYMENT MECHANISM
DESIGN DEVELOPEMENT OF MODELS ANTENNAS Italy DESIGN DEVELOP. OF
MODELS HF POWER AMPLIFIER (HFPA) DESIGN DEVELOP. OF MODELS HIGH
FREQUENCY RECEIVERS (HFR1-HFR2) DESIGN DEVELOP. OF MODELS HF POWER
CONDITIONER (HFPC) HF SECTION (HFS) Italy
Slide 131
Work Breakdown Structure (4) S/W H/W DESIGN DEVELOP. OF MODELS
SOUNDER TIMER & CONTROLLER (STC) S/W H/W DESIGN DEVELOP. OF
MODELS SOUNDER PROCESSOR(SP) DESIGN DEVELOP. OF MODELS POWER
CONDITIONER (PC) DESIGN FREQUENCY GEN. (FG) DESIGN STABLE LOCAL
OSCILL. (SLO) DIGITALSECTION (DS) Italy MGSE H/W S/W EGSE DESIGN
AIT AIT / GSE Italy DEVELOP. OF MODELS DEVELOP. OF MODELS
Slide 132
SCIENCE TEAM ROLES AND RESPONSIBILITIES
Slide 133
Science Team Roles And Responsibilities (1) Team Member
Development Phase Role Mission Operations and Data Analysis Roberto
Seu Overall responsibility for complete experiment development and
implementation within project constraints Overall responsibility
for complete experiment operation within mission constraints and
for data quality Arturo Masdea Interfacing with the industrial
partner for the design and development of the experiment
Interfacing with the industrial partner for mission operations
Daniela Biccari Definition of on-board and on-ground signal
processing algorithms Optimization of on-board and on-ground signal
processing algorithms Costanzo Federico Overall responsibility for
science planning, modeling of structural and magnetic properties of
Mars crust Overall responsibility for science analysis
Slide 134
Science Team Roles And Responsibilities (2) Vittorio Formisano
Spectral characterization of locales with higher likelihood of
presence of subsurface liquid water Correlation with spectroscopy
databases for contextual subsurface water identification
Pierfrancesco Lombardo Definition of data processing and data
fusion algorithms Implementation of data processing and data fusion
algorithms Lucia Marinangeli Modeling of the Martian subsurface
geology with emphasis on features indicating past presence of water
Quick look analysis and public outreach activities Roberto Orosei
Modeling of EM propagation in the Martian crust, planning of data
archiving activities Implementation of data archiving activities
Giovanni Picardi Modeling of surface scattering, contribution to
system design and signal processing algorithms Optimization of
on-board and on-ground signal processing algorithms
Slide 135
Science Team Roles And Responsibilities (3) Sebastiano B.
Serpico Optimization of advanced signal processing and pattern
recognition techniques Implementation of advanced signal processing
and pattern recognition techniques
Slide 136
Washington Workshop 3,4 Dec 2001 Shallow Radar for Martian
Subsurface Studies: Mission Operations and Data Analysis Plans
Slide 137
Mission Operations As far as the ionosphere is concerned,
SHARAD will be equally capable of operating on the day and night
sides of Mars.As far as the ionosphere is concerned, SHARAD will be
equally capable of operating on the day and night sides of Mars.
Constraints may then be those arising from the overall mission
design:Constraints may then be those arising from the overall
mission design: e.g., electromagnetic compatibility may require the
radar to be operated only when the other instruments are switched
off, which occurs typically during the night-side part of the
orbit. SHARAD will be a table-controlled instrument, switching
among different modes of operation according to a pre-determined
sequence of commands.SHARAD will be a table-controlled instrument,
switching among different modes of operation according to a
pre-determined sequence of commands.
Slide 138
Cruise/Transition Orbit During the cruising phase towards Mars,
heaters, powered by dedicated power line, will be used under S/C
control to keep the instrument equipment within the survival
temperature range.During the cruising phase towards Mars, heaters,
powered by dedicated power line, will be used under S/C control to
keep the instrument equipment within the survival temperature
range. Health and safety checkout will be performed every TBD days,
together with measurements in receive-only mode to characterize the
noise environment.Health and safety checkout will be performed
every TBD days, together with measurements in receive-only mode to
characterize the noise environment.
Slide 139
Mapping Orbit Operations In the off state, heaters, powered by
dedicated power line, will be used under S/C control to keep the
instrument equipment within the survival temperature range.In the
off state, heaters, powered by dedicated power line, will be used
under S/C control to keep the instrument equipment within the
survival temperature range. At every switch-on of the radar a
certain amount of time (of the order of 3 minutes, TBC) is required
to pass the instrument into operation.At every switch-on of the
radar a certain amount of time (of the order of 3 minutes, TBC) is
required to pass the instrument into operation. Within a single
orbit, the instrument will be operated in any of its observation
modes, in any desired sequence.Within a single orbit, the
instrument will be operated in any of its observation modes, in any
desired sequence. Within an orbit, the radar can be operated
continuously or discontinuously.Within an orbit, the radar can be
operated continuously or discontinuously. The time limit is set by
the portion of overall data volume allocated to SHARAD vs. the
selected operational mode selected.The time limit is set by the
portion of overall data volume allocated to SHARAD vs. the selected
operational mode selected.
Slide 140
Instrument Performance Evaluation The SHARAD Team will provide
specific software to the Mission Operations System with the
capabilities to monitor the status of the experiment.The SHARAD
Team will provide specific software to the Mission Operations
System with the capabilities to monitor the status of the
experiment. A quick look capability for the status of the
instrument will be achieved by sorting out and interpreting only
the housekeeping source packets. This will provide a check of the
state-of-health of the instrument before any data analysis is
performed.A quick look capability for the status of the instrument
will be achieved by sorting out and interpreting only the
housekeeping source packets. This will provide a check of the
state-of-health of the instrument before any data analysis is
performed. The monitoring of the instrument status will provide
inputs for subsequent instrument operations planning (selection of
operating modes, amplifier gain, calibration sequences, etc.).The
monitoring of the instrument status will provide inputs for
subsequent instrument operations planning (selection of operating
modes, amplifier gain, calibration sequences, etc.).
Slide 141
In-Flight Calibration Requirements Periodic calibration
activities will include:Periodic calibration activities will
include: Noise characterization: collection of raw data in
receive-only mode, to characterize the noise environment, every TBD
orbits.Noise characterization: collection of raw data in
receive-only mode, to characterize the noise environment, every TBD
orbits. Transfer function evaluation: very short raw data
collection (i.e. even a single pulse, in principle), over
sufficiently smooth surfaces so that radar pulse reflection can be
considered specular, every TBD orbits.Transfer function evaluation:
very short raw data collection (i.e. even a single pulse, in
principle), over sufficiently smooth surfaces so that radar pulse
reflection can be considered specular, every TBD orbits.
Slide 142
Sequence Designs Total coverage of polar deposits through
night-side observations is the minimum requirement for science
operations.Total coverage of polar deposits through night-side
observations is the minimum requirement for science operations. We
require access to all latitudes when spacecraft is on the night
side, although coverage is required to be continuous only over the
polar deposits.We require access to all latitudes when spacecraft
is on the night side, although coverage is required to be
continuous only over the polar deposits. Limited day-side
observations of polar deposits and targets subject to variations
over time can be required.Limited day-side observations of polar
deposits and targets subject to variations over time can be
required.