Abmd70.172
net.columbia
utzoo!decvax!duke!bmd70!jcp
Mon Nov 23 23:51:17 1981
Aviation Week 11/23/81
Highlights of the November 23, 1981 Aviation Week and Space Technology:
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This issue of the Aviation Week Digest contains only info on
the flight of Columbia, STS-2, due to that large number of
articles related to the mission. A military/weapons issue
will also be prepared seperately
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Problems Delay Columbia Turnaround
----------------------------------
Shuttle program officials said that the Columbia is in considerably
better shape after STS-2 then after STS-1, including damage to fewer than
3 dozen of the approximately 30000 Thermal Protection System (TPS) tiles.
Two failure modes of TPS tiles not previously encountered are
stripping away of the outer tile layer, and small blisters in the outer
tile coating. Shuttle deservicing ops were about 2 and a half days behind
schedule becuase of problems with the quick disconnect fittings at the aft
end of the orbiter, and a spill of about 5 gallons of sodium hydroxide,
an oxidizer scrubbing compound. Ferry of the shuttle back to Kennedy
Space Center is set for no earlier than Nov. 25th, with an overnight
stop at Bergman AFB, Texas.
Results of the TPS tile inspection on landing are:
6 tiles lost portions of the outer coating in the area of the
starboard chine. Nearly the entire surface of 2 tiles
was lost.
A dozen tiles in the body flap area had blisters in their surfaces
ranging from 1/8th to 1/2 inch in size.
TPS blanket material on the forward end of the starboard OMS
pod was charred, although damage should be easily repairable.
Several areas on the body flap sustained small gouges from 1/4
to 1 inch in size, believed to have occurred during launch.
Tiles behind landing gear were damaged by strain gage wires
1 tile on the left hand nose gear door sustainged a surface chip,
toward the aft end of the door.
Fuel cell evaluation will wait until the shuttle is returned
to the Kennedy Space Center. No damage was sustained due to launch over-
pressures.
Shuttle turn-around is scheduled for 10 days for STS-2, compared
to 14 days for STS-1
Shuttle AUTOLAND Performs Well on Approach
------------------------------------------
The shuttle's AUTOLAND system, computer guided approach & landing
procedures, functioned satisfactorally on STS-2. The Microwave Scanning
Beam Landing System (MSBLS) started functioning at 18000 feet and 8 n miles
from touchdown point. This system gathers continuous range, azimuth and
elevation information. AUTOLAND was engaged at 10000 feet and controlled
the orbiter thru final approach until Commander Engle took manual control
at 2000 feet for the preflare manuever.
Final program goal is to use AUTOLAND throughout touchdown and
rollout under conditions of zero ceiling and zero forward visibility.
MSLBS provides better information than a conventional instrument landing
system and is flexible enough to accomodate the steep glideslope and
two-phase landing flare procedure used by Columbia.
MSLBS is built by Eaton Corp's AIL Div, which has build 7 such
system ground stations under contract from NASA, including the one at
Edwards Air Force Base.
Landing Smooth Despite Weather
------------------------------
Columbia's landing was smooth despite weather that caused post-
ponement of the crosswind landing test until the third mission.
When Astronaut John Young, STS-1 Commander, flew an approach to cross-
wind runway 15 in the NASA Gulfstream 2 training aircraft 1 hour 10 minutes
before the shuttle landing, cross winds were in the vicinity of 18 mph.
While the Columbia can land in up to 20kt crosswinds, it was decided that
a max of 15 kts should be used for the first crosswind test, hence the
postponement.
Shuttle acquisition as the vehicle approached California was
at 1:08 PM, at a range of 650 miles from Edwards, traveling Mach 15 at
188000 ft. Voice acquisition was a few minutes later, when the shuttle
was about 25 miles south of its nominal ground track.
Columbia was converging on nominal ground track as it crossed
the California coast at 1:18 PM, doing Mach 6.5 at 125000 ft.
Columbia passed overhead at Edwards at 50000 ft and Mach 1, causing
two successive sonic booms about 10 seconds later. Bursts of white contrails
were visible, which were due to Columbia's yaw control system jets firing.
The pitch and roll jets stopped operating automatically soon after atmosphere
interface, but the yaw jets continue, as they do not interfere with aero-
dynamic control.
Commander Engle took over control at 40000 feet, and flew the
Heading Alignment Circle (HAC) using control stick steering. In the
next 2 and half minutes, Columbia lost 33000 ft of altitude.
Launch Crowd
------------
NASA estimated that 20,175 spectators veiwed STS-2 launch from
NASA grounds, another 10 to 12 thousand watched from Cape Canaveral
Air Force Station, with about 250 thousand viewing from off government
territory.
This was about half those present at STS-1.
Fuel Cell Failure Assessed
--------------------------
Failure of one of the fuel cells was believed to be due to blockage
of one of four hydrogen flow ports. Blockage of hydrogen flow would result
in a dilution of the electrolyte, causing water buildup in the cell. This
condition would snowball, resulting in complete power loss from the cell.
Reentry Manuevers Expand Aerodynamic Envelope
---------------------------------------------
Aggressive reentry maneuvers flown during STS-2 reentry will expand
the body of knowledge about wing performance at high altitudes and speeds.
Loss of the aerodynamics coefficient indentification package (ACIP) data was
due to a recorder failure, although on STS-2 the development flight
instrumentation was active during reentry, permitting recovery of some of
the new data.
Nineteen groups of manuevers were performed, some as close as 20
seconds apart, requiring substantial coordination between Engle and Truly.
9 of the manuevers were conducted during communications blackout.
A large quantity of OMS and reaction control system propellent
was dumped before reentry, in order to move the center of gravity of the
orbiter aft, due to the shortening of the mission. This was done by
firing two opposing yaw control jets before the deorbit burn.
NASA Assessing Launch Ascent Performance
----------------------------------------
Abort oriented milestones during launch ran about 10 seconds late,
possibly a result of slightly degraded solid rocket motor performance. If
the SRB's were cooler than normal, this would have occurred. The most
notable incident was that the nominal 5 second single SSME out abort to
Rota, Spain period was lengthened to 18 seconds. This abort option occurs
between the end of abort-return to launch site, and before start of
abort-to-orbit phase.
Manipulator Arm Testing Meets Limited Objectives
------------------------------------------------
Space deployment and recovery of heavy cargo was brought closer
to reality during STS-2, despite the minimum mission configuration.
Data obtained were:
Deploy, maneuver and reposition the Canadian RMS arm
Dynamic characteristics of the system
Structural data using several control modes
Data lost due to mission shortening are:
4 hr. test instead of 12 hr.
Complete software performance check
Joint-reach limit condition
Orbiter inspection using the arm
Initial comments indicate that arm performance was nominal, almost
exactly as preflight models showed it would. Arm and payload bay mounted
TV cameras provided important engineering data as well as pictures of the
operation.
Two failures occurred during arm testing, towards the conclusion of
the test series:
The shoulder yaw joint froze during the recradling operation,
Truly switched to a different mode of control to complete
recradling.
A circuit breaker tripped after recradling, causing loss of
both TV cameras.
The shoulder joint failure was traced to the failure of a backup
drive motor, which was not critical, as the primary was still operational
at the time.
Overpressure, Pad Modifications Survive Launch
----------------------------------------------
Damage to mobile launch platform 39A was less than on the first
launch, and a test of the overpressure waterflood system was conducted
30 hr. after launch. A few areas of the pad were damaged more severly
than on STS-1, but most areas showed less damage than before.
SRBs survive STS-2 Better
-------------------------
Structural damage to SRBs from STS-2 launch was about half of
that on STS-1, according to initial analysis. The SRBs were in the
water several days longer than on STS-1, resulting in increased
corrosion on the casings. The external tank tumbling systems performed as
per spec on STS-2, after failing on STS-1, causing the tank to tumble
end over end at 4.8 deg per second, to insure atmospheric breakup of the tank
Splashdown of external tank components was at 31.67 deg S latitude, 95.66
deg E longitude in the Indian Ocean. Tank seperation was at 8 min 54
seconds after ignition of SSMEs. It coasted 256 seconds before impact.
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Summary prepared by J.C.Pistritto, (duke!bmd70!jcp@brl)
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The Usenet Oldnews Archive: Compilation Copyright (C) 1981, 1996
Bruce Jones, Henry Spencer, David Wiseman.
