Date post: | 10-Apr-2018 |
Category: |
Documents |
Upload: | bob-andrepont |
View: | 222 times |
Download: | 0 times |
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 1/8
/4;, Y,'~c;( 9
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION TES WO ?-41t5N E W WASHINGTON, D.C. 20546 WO 3W-625
FJR RELEASE: FRIDAY P.M.April 19, 1968
RELEASE NO: 68-68
REENTRY F EXPERIMENT
A f l i g h t experiment in aerodynamic heat ing a t speeds up
to 13,500 miles-per-hour wil l be launched Apr. 25 by th e
National Aeronautics and Space Administration from Wallops
Sta t ion , Wallops I s land , Va.
Purpose of th e experiment, known as Reentry F, is to
measure heat transfer in a slender cone at hypersonic
speeds for comparison with ground studies. Scientists
are unable, even with the best available laboratory facilities,
to simulate al l at once complex variables governing aero-
dynamic heating. For that reason flight experiments ar e
needed to provide a basis for useful ground test results.
The objective is to obtain in flight fundamental research
data on aerodynamic heating and th e t r ans i t ion from laminar
(smooth) to turbulent flow in th e boundary layer.
-more- 4/12/68
j I- ~
-.
)
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 2/8
The payload ofReentry F is a graphite-tipped beryllium
cone 13 feet long, tapering from 0.1 inch a t the nose to 27.3
inches at the base. When it separates from the rocket third
stage, the cone and its internal instruments will weigh 600
pounds. It will be launched on a Scout rocket.
The experiment was designed by NASA's Langley Research
Center, Hampton, Va. Reentry F is the sixth flight in a re.
entry heating series sponsored by the Office of Advanced Re-
search and Technology (OART).
Fo r this experiment, three of th e Scout's four stages will
be used. Two will fire on the ascending portion of the flight
trajectory, and the third will drive the instrumented payload
to hypersonic speeds after it has passed its apogee (highest
point) and is descending into the atmosphere.
Aerodynamic heating, the phenomenon which causes a meteor
to flare as it streaks into the Earth's atmosphere, is rea-
sonably well understood in relation to flight of high speed
aircraft, missiles and spacecraft. Much research and engi-neering has been done to protect flight vehicles against its
effects -a heat sh ie lds of manned spacecraft owr
examples. IX o/ 4
mr-
I'I
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 3/8
-3-
Th e less familiar term "boundary layer" refers to the
layer of air close to the surface of a moving object in flight.
The moving object carries a very thin sheet of air molecules
held to it s surface by friction. These molecules rub against
their neighbors, generating heat which increases as speeds go
higher.
When the molecules nearest the vehicle surface slidesmoothly over their closest neighbors, the boundary layer is
said to be "laminar" or smooth. Designers would prefer to
have smooth attached boundary layers over the entire surface,
fo r they reduce air friction (drag) and heating.
The boundary layer is sensitive to many factors Including
speed, pressure, vehicle shape, surface roughness and tempera-
ture. Instead of remaining smooth, it frequently begins a
churning or turbulent motion, and the "scrubbing" action in
th e turbulent zone greatly increases aerodynamic heat ing.
When th e fac tors which cause turbulent boundary layers
and higher heat ing rates are more thoroughly understood
through research, designers of m a n y types of hypersonic ve-
hicles will benefit by being be t t e r able to promote or pro-
long smooth, laminary boundary layer conditions.
-more-
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 4/8
-4-
Transition from laminar to turbulentboundary layers
sometimes can be observed in a column of smoke ascending from
a chimney into still air. Smoke will rise smoothly and un-
disturbed for a considerable distance, then at some point it
will begin churning and billowing, which signals turbulent
flow,
The slender cone-shaped spacecraft selected for the Re-
entry F experiment is expected to develop turbulence from about
two feet behind its sharp graphite tip down to its base. In
that area turbulence in the boundary layer should result in
measurably higher rates of heating.
The results of the Reentry F experiment will be useful
in designing hypersonic aircraft, lifting entry vehicles,
slender missiles and other advanced vehicles. Reliable date
and a theoretical basis for aerodynamic heating
analysis are required for efficient design.
REENTRY F SPACECRAFT
Since heating rates are of the prime interest, th e
entire outer shell of the Reentry F spacecraft is a beryllium
calorimeter or heat measurement device. It consists of seven
segments, each 0.7 inch thick. Near its base are 81.x quartz
antenna windows. The graphite nose tip is 7.5 inches long.
-yaore-
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 5/8
Embedded in the beryllium calorimeter segments are 21thermal sensors, each having four thermocouples located at
different depths. Four more thermal sensors are mounted on
the base cover, an d 13 pressure ports are located along the
conical shell and on the base to verify the predicted pressures.
Within the conical shell and separated from it except
fo r a minimum of attachment points is a cylindrical package
fo r instruments an d power supply. The separation is essential
ti o assure accurate aerodynamic heating measurements by the
calorimeter.
The package contains a telemetry transmitter an d it s
associated electronics, accelerometers, gyros, a tracking
beacon an d the necessary power supplies. Telemetry will be
transmitted throughout the flight and playback is no t neces-
sary because no significant signal attenuation (blackout) is
expected during the reentry.
Th e payload and backup were built by the General Electric
Company's Re--entry Systems Department under contract to the
Langley Center, which is managing the reentry project.
LAUNCH VEHICLE AND FLIGHT PLAN
A three-stage Scout will launch th e Reentry F Experiment
to reenter a heavier than normal spacecraft at a sub-orbital
velocity of 13,500 mpn.
-more-
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 6/8
-6-
The first two stages provide boost and coastto an
apogee altitude of about 115 miles. The Scout guidance
system orients the vehicle to its desired reentry angle
of 20 &egrees below the horizontal, On the descending leg
of the trajectory, the third stage ignites at about 100
miles altitude.
Before separation of the spacecraft about 55 miles aboveEarth, a pair of small rocket motors will ignite to give it aspin rate of about 55 rpm and a speed of 13,500 mph. Theprimary data period of the experiment will begin at 21 milesand will continue until the calorimeter begins to melt around10 miles altitude. The payload will impact in the Atlantic
Ocean 140 miles northeast of Bermuda,some 800 miles from
Wallops Island.
TRACKING AND DATA ACQUISITION
Radar, telemetry and optical coverage will all play apart in gathering detailed information on the flight of Re-
entry F.
Primary telemetery stations are Bermuda and the WallopsStation telemetry ship Range Recoverer. Radar data will begathered by Bermuda and an Eastern Test Range radar ship
Twin Falls Victory. Two NASA aircraft flying northeast ofBermuda will provide optical observations and additional
telemetry coverage.
-more-
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 7/8
-7-
Tracking to apogee will be accomplished from Wallops,
and the Bermuda Station will track the payload into the re-
entry area.
Atmospheric density and temperature measurements will
be made by ARCAS sounding rockets launched from Bermuda be-
fore and after the flights, supplemented by weather balloons
from Bermuda and the Range Recoverer.
Total darkness and no more than one-quarter local cloud
cover in the reentry area are required to assure optical
coverage of the flight, so launch windows occur at night.
SCOUT REENTRY HEATING PROJECT OFFICIALS
Following are the key off ic ia ls fo r the Scout Reentry F
Project:
Reentry F Experiment - Langley Research Ccnter
Eugene C. Draley, Assistant Director for Flight Projects
E. C. Hastings, Project Manager, Reentry F
James L. Raper, Assistant Project Manager
Howard S. Carter, Experimenter
John N. Daniel, Tracking and Data Acquisition
Scout launch Vehicle
R. D. English, Head, Scout Project Office
B. Leon Hodge, Operations Director
Robeic A. Schmitz, Payload Coordinator
E. Eugene Hall, Systems Integration Engineer
-more-
Kl
8/8/2019 Reentry F Experiment
http://slidepdf.com/reader/full/reentry-f-experiment 8/8
Wallops Station
Robert T. Duffy, Test Director
Tom W. Perry, Jr., Project Engineer
NASA Headguarters
W. A. Guild, Chief, Space Flight Projects, OARTP. J. DeMeritte, Technical
Associate, Reentry FExperiment, OART
J. Levine, Project Officer, Reentry F Project, OAR'
P. E. Goczh, Manager, Scout Program, Office of Space
Science and Applications
General Electric Cmrnpany
E. W. Richardson, Manager, Reentry F Program
-end-
pi
I--_
_ _ _ _ __ _ _ _ _ _ _ _