Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/jplnews/0401.ZIP/0401.PR

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OFFICE OF PUBLIC INFORMATION
JET PROPULSION LABORATORY, CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIFORNIA.  TELEPHONE [phone]

                                           July 28, 1966

                       SURVEYOR I MISSION

         The National Aeronautics and Space Administration's
Surveyor I spacecraft made a perfect low-speed, three-point
landing on the Moon on June 1, 1966, after a 63-hour, 36-minute
flight from Cape Kennedy.
         During the following six weeks -- before the Sun set,
rose again 14 Earth days later and set a second time on
Surveyor's landing site in the Ocean of Storms -- the
spacecraft's survey television camera scanned for transmission
to ground communications stations 11,150 high-resolution
pictures of the lunar surface.
         From the pictures were derived the representative
colors of the Moon's surface, an accurate view of the terrain
up to one-and-one-half miles surrounding the spacecraft, the
effect of the landing upon the surface and visual evidence of
lunar environmental damage to Earth-made objects.
         By July 13, Surveyor I's 42nd day on the Moon,
America's first remote observatory had done the unexpected.  It
had survived the intense heat of the day (250 degrees
Fahrenheit), the cold of the two-week-long lunar night (minus
260 degrees F.) and a second full Moon day. N

                              -2-
         Surveyor continued to accept Earth commands and
transmit TV pictures through the end of the second Moon day
even though its main battery, not expected to endure the rigors
of the lunar environment for so long a time, had been faltering
for nearly a week.
         Whether it will function a third lunar day is not yet
known, but the possibility is considered remote.
         Designed and built for NASA by the Highes Aircraft
Company of Culver City, California, under technical direction
of the Jet Propulsion Laboratory, Surveyor I greatly exceeded
its objectives in gathering surface data necessary to the
Apollo manned lunar landing program.
         The first of seven lunar soft landing missions planned
for 1966 and 1967, Surveyor I was designated an engineering test
flight for demonstration of the Atlas-Centaur launch vehicle;
mid-course and terminal maneuvers by the spacecraft; a radar-
and-rocket-controlled soft landing; and maintenance of constant
communications between the spacecraft and the Deep Space Network
ground stations during the flight and after landing.
         Surveyor I lifted off Pad 36-A at Cape Kennedy within
one second of its planned launch time--7:41:01 a.m. Pacific
Daylight Time--on May 30.
         The perfect countdown was followed by a boost into
space by the Atlas-Centaur that would have put the spacecrarft
on the Moon within 250 miles of the aiming point.  The precise
launch made the requirement for a trajectory correction some 16
Z

                              -3-
hours later one of minimum proportion.  At the mid-course
maneuver, the velocity change was 45 miles per hour, only a
fraction of which was applied to the slight injection error.
         All launch vehicle and spacecraft events thorugh
Canopus acquisition occurred satisfactorily and at nominal
times with the exception of the deployment of one of Surveyor's
two low-gain omnidirectional antennas.
         Both antennas and the spacecraft's three landing legs
were commanded by the Centaur programmer about 12 minutes after
liftoff to extend from their folded launch position to the
flight and landing position.  Telemetry from the spacecraft
indicated that Antenna A apparently had not deployed fully, if
at all.
         Two-way communications lock was achieved by the Deep
Space Net station in Johannesburg, South Africa, at liftoff
plus 28 minutes, transferring control of the mission from the
Eastern Test Range to the Space Flight Operations Facility at
the Jet Propulsion Laboratory in Pasadena, California.  Commands
were transmitted immediately to Surveyor to deploy the antenna
in question, but telemetry and signal strength readings indi-
cated no change.
         Although the minor failure was not expected to
jeopardize the mission--either from the standpoint of communica-
tions or the slight change in the spacecraft's center of gravity
--the exact position of Antenna A remained undetermined through-
out the flight, a concern in itself. V

                              -4-
         (Later, however, after Surveyor I touched gently down
on the Moon, telemetry showed that the antenna was properly
extended.  Television pictures from Surveyor's camera of both
the antenna and its latching mechanism provided verification of
this.  It remains unknown whether the antenna deployed during
retro fire or upon spacecraft contact with the lunar surface.)
         Surveyor's original aiming point was 3.25 degrees
south of the lunar equator and 43.83 degrees W. Longitude in
the southwest portion of the Ocean of Storms.  In planning the
mid-course maneuver, executed at 11:45 p.m. PDT May 30, the
Surveyor space science analysis team selected a new target
about one degree farther north in latitude.  The new
coordinates were 2.33 degrees South, 43.83 degrees West, a
point scientists expected to be smooth enough for a safe
landing.  Tracking data throughout the remainder of the flight
indicated Surveyor landed at 2.411 degrees South and 43.345
degrees West, about nine miles from the modified aiming point.
         The critical terminal descent began 31 minutes and
2000 miles from the Moon at 10:46 p.m. PDT June 1 with roll and
yaw maneuvers to align Surveyor's retro rocket with its approach
direction, just five degrees from local lunar vertical.
         At 11:14 and 39 seconds, an altitude marking radar
sensed the nearness of the Moon--59.35 miles altitude--and
started the automatic sequence that fired the spacecraft's main
retro motor 10 seconds later. T

                              -5-
         The 9000-pound-thrust solid propellant rocket ignited
at two minutes and 46 seconds before touchdown when Surveyor I
was 46.75 miles above the Moon and travelling at a velocity of
5840 miles per hour.
         The 39-second main retro phase slowed the spacecraft
to 267 miles an hour at 35,000 feet altitude.  The rocket motor
case was ejected at 31,000 feet, and three smaller rocket
engines, which stabilized the spacecraft during main retro fire
and earlier powered the mid-course maneuver, continued to slow
the descent.
         Throttled by information from Surveyor's radar alti-
meter and doppler velocity sensor (RADVS), the verniers reduced
the spacecraft's speed to 71.4 miles per hour at 1000 feet
altitude and 2.8 miles an hour when they cut off about 10 feet
above the surface.
         Surveyor free-fell the last 10 feet of the flight, its
first leg touching the lunar surface at 11:17:35.651 p.m. PDT.
Within 19 milliseconds it had three feet on the Moon.  Landing
speed was about 7.5 miles per hour.
         Strain gauge readings from the three landing legs
recorded a "second touchdown" less than one second later, indi-
cating that the spacecraft bounced about four or five inches.
         Television pictures taken by Surveyor during the next
several weeks showed that at least one of the three crushable
blocks under its frame gouged the lunar surface as the shock  T

                              -6-
absorbers compressed at touchdown.  The aluminum honey-comb
block made a "cookie cutter" imprint on the Moon just below the
spacecraft.
         After a series of engineering interrogations to confirm
that all spacecraft systems had survived the landing, Surveyor I
took the first of 11,150 pictures at 11:53 p.m. PDT June 1.  The
200-scan-line, wide-angle (25-degree field of view) picture
showed a portion of the spacecraft framed against the surface
of Moon.
         Thirteen additional 200-line pictures were transmitted
to the Pioneer station of the Goldstone Space Communications
Complex in California before the solar panel was positioned for
power conversion and Surveyor's high-gain antenna was pointed
at the Earth for transmission of higher quality 600-line
pictures.
         With the high-gain antenna so positioned and the ease
with which it was maneuvered during the following days, the
Surveyor camera did not return to the 200-line mode until the
last day of operation on July 13.  Picture count at lunar sunset
on June 14 was 200-line pictures, 14; 600-line pictures, 10,324.
         A scan conversion system at JPL made it possible to
display Surveyor pictures in real time on conventional TV
monitors at the Laboratory as they were relayed from the Moon
via microwave from Goldstone.  During the night of June 1 and
the morning hours of June 2 when Surveyor took its first 144  X

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pictures, commercial television networks further relayed the
live lunar program throughout the nation.  The Early Bird
satellite carried the pictures even further--to Europe.
         Nearly all the television pictures were commanded and
recorded by the Goldstone station during communications periods
that varied from 8 to 10 hours each day.  A few picture
sequences originated at the Deep Space Net station at Canberra,
Australia, which, along with the Johannesburg station, served
as prime monitors of engineering telemetry from Surveyor.  The
Madrid, Spain, station and the Mars Site (210-foot antenna) at
Goldstone were backup stations during the mission.
         More than 82,000 ground commands to Surveyor were
transmitted from the Goldstone station from May 30 to June 14.
During its most productive session over Goldstone, June 10,
Surveyor took 1758 pictures of the Moon and received and acted
upon more than 12,000 commands.  Six hours and 37 minutes of
the 10-hour, 20-minute communications pass were devoted to
picture transmission.
         Early in the mission, it was expected that the camera
would necessarily be shut down for several days at lunar mid-day
because of the extreme heat.  However, at lunar high noon on
June 7, as the Moon's surface temperature approached 250 degrees
the camera was shaded by the solar panel and the high-gain
antenna and continued to operate within its thermal limits.  The
camera was de-activated June 8 and 9 when it was exposed to the
Sun. V

                              -8-
         In addition to the lunar surface pictures taken by
Surveyor's camera from its vantage point only four feet above
the surface, the spacecraft performed a number of other post-
landing operations.  Moon's-eye views of the bright stars Sirius
and Canopus were photographed by the camera in an effort to
ascertain more closely the exact location of Surveyor on the
lunar surface.
         On June 6, an attempt was made to photograph a portion
of the Earth, but the planet was just out of view, above the
elevation range of the tilting mirror of the camera.
         Several attempts were made to disturb the lunar surface
or create a small dust cloud near one of the spacecraft's three
landing feet by firing bursts of nitrogen gas from Surveyor's
attitude control jets.  No disturbance or dust was discernible
in TV pictures taken during and after the firings.
         Because of the continuing excellent condition of the
spacecraft after it had operated on the Moon for more than a
week, it became apparent that Surveyor had a strong chance of
surviving the lunar night.  This possibility was taken into
account during formulation of plans for the spacecraft's
operation on the final day of sunlight June 14.
         During the final Goldstone pass, the camera recorded
another 523 pictures as the Sun sank lower on the horizon.
Many of the pictures taken with the low Sun behind the
spacecraft showed perfect silhouettes of Surveyor shadowed
against the Moon's surface. X

                              -9-
         At lunar sunset, 9:18 a.m. PDT June 14, the camera was
commanded to point toward that portion of the horizon where the
fireball disappeared and a number of pictures were taken of the
solar corona, the Sun's upper atmosphere.
         Surveyor I made its last picture of the first lunar
day at 9:37 a.m. PDT after night had fallen on the spacecraft's
small segment of the Ocean of Storms.  It portrayed Surveyor's
footpad No. 2 lighted only by the Sun's reflection off the
Earth.  The camera's shutter, normally providing an exposure
time of 150 milliseconds, was held open for four minutes for
the single "Earthshine" picture.
         After taking 10,338 pictures during 12 1/2 days of
operation on the lunar surface, Surveyor's camera was shut down
for the duration of the night.  Temperatures already were
dropping rapidly on the spacecraft.  The battery, however, was
nearly fully charged with a capacity of 162 ampere hours.
Maximum capacity of the battery is 165 hours.  At touchdown on
June 1, telemetry indicated 57 ampere hours.
         For the following two days, the spacecraft was queried
periodically concerning its condition--voltages, temperatures
and battery power capacity--by round-the-world stations of the
Deep Space Network.
         Surveyor went deeper into "hibernation" on June 16,
conserving its stored electrical energy and expending only
enough to keep itself warm during the long, cold night.  The  R

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only systems functioning in the power-conservation fashion were
the two radio receivers and the command decoder to accept
commands from space communications stations on Earth.
         The solar panel had been positioned so that at dawn
the Sun would not strike the power-converting cells, sending a
sudden surge of current into the chilled electronics systems.
It was expected that several days after dawn Surveyor would
warm up to the point where the battery would provide the space-
craft with enough power to permit reception of commands and
movement of the solar panel toward the Sun for a slow and easy
battery charge.
         Pointing the solar panel toward the western lunar sky
above the horizon had a second purpose.  The panel and the high-
gain antenna, positioned nearly parallel to the mast atop which
they are mounted, would provide a surface area large enough to
cast long shadows on the lunar terrain.  Should Surveyor fail
to come back to life, the shadows could be photographed from
above by the first Lunar Orbiter spacecraft.
         On June 28, just a few hours before sunrise on
Surveyor, commands to turn on the spacecraft transmitter were
sent from the tracking station at Goldstone.  No response was
received.  For several hours each day thereafter, Goldstone
sent the same commands.  The station at Canberra took over the
wake-up duties on July 3 and finally aroused Surveyor from its
power-conserving sleep at 4:29 a.m. PDT on July 6. X

                              -11-
         In preparation for picture-taking activities during the
second lunar day, engineers and scientists at JPL sent commands
via Goldstone on July 7 to operate Surveyor's camera.  Twenty-
four pictures were taken as the camera proved to be in good
working condition.  It was planned to use the camera again
during the final three days before sunset, expected about 7:30
p.m. PDT on July 13.
         Possible failure of the battery because of excessive
heat was detected two days later by JPL and Hughes Aircraft
Company engineers monitoring temperatures, voltages and other
readings from the telemetry.  Battery temperature began rising
rapidly and by 1 p.m. PDT on July 9 had reached 129 degrees F.,
just 12 degrees below the maximum design limit.  Three hours
later, the temperature was at 134 degrees but rising at a lower
rate because the solar panel had been turned almost completely
away from the Sun to reduce the battery charging rate and, as a
result, the internal temperature of the battery.
         Emergency measures were taken to take advantage of
what was then believed to be the last few hours of Surveyor I's
operational life.  Responding to commands from the Deep Space
Net station at Canberra, the TV camera took 38 pictures of the
lunar surface.
         An attempt was made to fire the three liquid propellant
rocket engines at a low thrust level to stir up Moon dust or dig
a hole in the surface just below the rocket nozzles.  The  Z

                              -12-
attempt was unsuccessful because of the inability to turn on,
by ground command, power circuits that operated the engine
valves to release propellants into the thrust chambers.
         Commands also were transmitted from Canberra to turn
on Surveyor's approach television camera, which was designed
for but not used during final phase of the flight from Earth to
the Moon.  No video information was received, but telemetry
indicated that the camera electronics did function properly.
         By the time operations were concluded on July 9, the
battery temperature had climbed to and leveled off at 139.8
degrees.  At noon the following day, the temperature had fallen
to 130 degrees and, 24 hours later, to 115 degrees, well within
the operating range of the battery. The battery was designed to
operate at temperatures from 40 to 125 degrees F.
         As the battery temperature decreased, the solar panel
was repositioned periodically to step up the charge until full
charging rate was once again possible.
         Engineers believe the battery problem originated with
an internal short which generated internal heat.  Telemetry
indicated that battery pressure fluctuated and that the sealed
battery case had ruptured.  Reason for the battery's brief
recovery is not known.
         With the battery problem unsolved but less critical,
picture-taking was resumed on the morning of July 12 when 257
TV shots of the lunar surface were received at the Goldstone
station.  A number of the pictures revealed visually for the
first time lunar environmental damage to Surveyor. ^

                              -13-
         The pictures showed that one of the mirrored glass
thermal radiators atop Compartment A, used to dissipate heat
from temperature-sensitive electronics, shattered during the
long, cold night when it was subjected to temperatures
approaching minus 300 degrees F.  At these temperatures, the
stresses.
         The compartment, covered by 36 of the glass radiators,
houses two radio receivers, two transmitters, the main battery
and other equipment designed to operate between 40 and 125
degrees F.  None of 24 glass radiators on a second compartment
were damaged by the extreme cold.  The shattered segment of
glass, representing less than one-sixtieth of the total radiator
area, had a negligible effect on spacecraft performance.
         One-hundred fifty more pictures were recorded at
Canberra and Johannesburg on the night of July 12 to complete
the record of "shadow progression".  About a dozen pictures
were taken each hour upon command from the overseas stations.
Areas portrayed were illuminated by the low-angle Sun and show
shadow growth hour by hour.
         Surveyor I entered its 42nd day with a weak, but
functioning, battery.  After 334 pictures were received at
Goldstone, the high-gain antenna and solar panel were again
positioned as they were at the first lunar sunset June 14.
         When control of Surveyor passed to the Johannesburg
station just a few hours before dark on the landing site, the  R

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spacecraft's camera was made ready for 200-scan-line pictures
of the solar corona.  Sunset was expected at 7:38 p.m. PDT on
July 13.
         At about seven o'clock, two test pictures were taken to
insure that the camera was working properly.  (The 200-line mode
had not been used since June 2 when the high-gain antenna was
pointed toward Earth for the first time.)  There were to follow
several dozen carefully timed pictures of the western horizon
as the Sun disappeared.  The camera would pan across the sky
above the horizon without pointing directly at the Sun itself.
         As each of the next few pictures were transmitted from
Surveyor, spacecraft telemetry showed large battery voltage
drops indicating that the battery, then operating without the
support of solar power, was dying.  Night-time temperatures,
dropping rapidly at sunset, pushed the battery voltage still
lower.
         The Johannesburg station lost communications with
Surveyor at a few minutes before 8 p.m. PDT after the ninth
200-line picture was recorded.  The loss of radio lock occurred
before the corona could be photographed.
         Throughout the night and until 5:30 a.m. on July 14,
engineers at JPL and at the Johannesburg station attempted to
resume communications with Surveyor.  The effort was abandoned
when the Moon was out of view of the South African station.
         The possibility that Surveyor I would survive a second
lunar night was believed to be very remote.  However, project  ^

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officials did not discount the chance that the spacecraft could
come back to life during the afternoon of the next lunar day
(second week of August).
         Although the operational phases of the mission ended
July 14, Deep Space Network stations are expected to tune in on
Surveyor again in the event the spacecraft is revived by the
generation of power by the solar cells.
         Surveyor's TV picture total now reads:  First lunar
day, 10,338; second lunar day, 812.
         Surveyor I transmitted its last picture to Earth less
than one week before the second flight spacecraft was shipped
to Cape Kennedy from the Hughes Aircraft Company facility in
El\Segundo, California.


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