Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
MAROC-TUBSATand
LAPAN TUBSAT
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
• MAROC-TUBSAT Mission Goals– Test of the advanced attitude control system– teach the Morocians in microsatellite construction, operations,
space condition requirements and orbital mechanics
• Satellite Bus• Operation
• Payload• Operation
Royal Institute for EarthObservation RABAT
Technical University of Berlin
MAROC-TUBSAT Project
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
MAROC-TUBSAT Split View
• Mass: 47 kg• Cube: 32×34×36.2 cm
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
MAROC-TUBSAT Payload Module (Rutherford)
• One CCD-sensors containing 770x576 pixel and a pixel size of 32 μm (incl. Near infrared)– focal length 72 mm– fov 8°– nominal integration time 28 ms– only photo
• S-Band transmitter– BPSK modulation– 2 W RF output– digital pictures or telemetry with 128 kbaud
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Attitude Control System• Three Wheel/Gyro-Units in
the three body axes– Wheel with integrated WDE
(built by TUB)– Fibre optic gyro µFORS-6
(built by LITEF)– Gyro is connected to integrated
WDE via serial communication interface
Operating modes Current control Angular velocity controlSpeed control Angle control Torque control
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Ground Segment International• Norway
– University of Svalbard (TTC)– SvalSat (Payload)
• South Africa– University of Stellenbosch– Overberg Test Range
Telemetry/Telecommand-
Station
Transceiver UnitVHF/UHF-Band
Yagi-Antenna
Telemetry/Telecommand1200 Baud
2.4 m Maroco/Rabat4 m SA/Stellenbosch
4 m SA/Overberg7 m Norway/Tromsoe
Digital Pictures125 kBaud
Bit-/Bytesynchronisation
Picture Storage
DigitalReceiver Unit
S-Band
Cooperated Satellite Control Center
Videodata are sendto Berlin via mail or
internetcould be
controlled fromBerlin via internet,
but normalautonomous
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
DLR- versus MAROC-TUBSAT
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
• Star Sensor is used occasionally (once per Day) to close the Outer Loop (Momentum Bias, Drift Rate less than 1° per Day, no man in the Loop)
• Can work worldwide - autonomously
• Payload Camera is used to close the Outer Loop (Man in the Loop, Zero Momentum Bias)
• Needs S-Band and TTC-station near observation area
DLR-TUBSAT
MAROC-TUBSAT
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Attitude Control System - Inertial• CCD Star Sensor
– developed by TU Berlin
• Operating Mode– Momentum Bias Mode– Momentum axis perpendicular to
orbital plane– Momentum axis direction is
known by 0.2°
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Attitude Control Operation Step 1.Sleep mode:
Satellite rotates around it’s Z-Axis with 1°/sec, momentum bias vector stands perpendicular to the orbital plane
2.First Attitude Acquisition: • Momentum bias vector is split up between Z and X-Axes
(primary to X). This defines the East/West position of image centre
• satellite rotates with 1°/sec around X; Y control circuit is nutation damping (30 min)
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
3.Second Attitude Acquisition:• If the satellite reaches its target solar
cell current (rising or falling flank) the RW reduce the rotation to 0.5°/sec (RPM mode)
• After one half of the nutation period the RW reduce the rotation to 0°/sec
• Angle step back to the target position by using RW-Gyro pair
• Fine adjustment every 5 sec until the time for first picture is reached.• Taking of 24 or 28 pictures and send the data down or taking one
picture and store it.• After completing the picture sequence the satellite goes back to sleep
mode.
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
TUBSAT Attitude Control
North pole
-Y
1
2
3
Region to be imaged
Ground track +Z
Sun
equatorGround track
Region to be imaged
1
2
3
+Z
trajectory
CROSS TRACK OFF-NADIR TARGET LOCKING
INTERACTIVE AND AUTONOMOUS MODES
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Operations• Satellite is rotating around momentum bias axis (hibernation mode)• Stabilize satellite rotation by rate command with wheel/gyro-units
(10 min before target)• Acquisition with sun vector information to point target and stabilize
(1 min before target)• Take picture of target• Store picture or send it down and make a new picture (max. 25
overlapping pictures)• Possibility of stereoscopic pictures• Switch off three wheel/gyro-units• Go back to momentum bias mode mode
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Flight Results: Pictures
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Long Time Monitoring
Interval of Events:
- Hourly, e.g. Weather (NOAA)
- Daily, e.g. Ice Movement, Vegetation This is the Typical Application for MAROC-TUBSAT
- Weekly or Monthly, e.g. City Expansion (Landsat)
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
An Example: Ice Monitoring for Icesail Expedition(Arved Fuchs)
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Detection of Ice free Shipping Lanes:
Gulf of Finland 20 March 2003Gulf of Finland 27 March 2003
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
-3D Bilaufnahme
-2 Bilder a 30 sec
-280 km stereo basis
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Disadvantages of MAROC TUBSAT• Target position must be known exactly• Too less storage capacity• To small focal lenght• panchromatic
Advantages of MAROC TUBSAT• Autonomous operation worldwide• Do not need S-Band and TTC station in contact range
of the target• Hibernation mode is easier to control
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
The near Future: LAPAN-TUBSAT• Similar to MAROC-TUBSAT with some Improvements:
– Color TV (3 Chip) Camera– Focussing on board– 1 m Focal Length– Star Sensor (CMOS)– 5 Battery Cells– Modified Shape
• 44 x 44 x 25 cm (instead of 32 x 32 x 32 cm)
• Launch is planned for October 2006
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
LAPAN-TUBSAT• Cooperation of TU-Berlin and LAPAN Indonesia
• Technical Part– Building of a microsatellite for earth observation with 6 m GSD– Sun Synchronous Orbit, Launch with PSLV (India)– Costs: 1 Million Euro
• Educational Part– Teaching of 10 engineers from LAPAN in Satellite design, choosing of
Components, test procedures, launch pad operations and satelliteoperation
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Final Goals
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Agriculture Observation
Satellite and Sounding Rocket Construction
The University Courses on Svalbard, Longyearbyen August/September 2006 MAROC- and LAPAN-TUBSAT
Ship monitoring – securing of fishingfields