Jul 12 1985
From The Space Library
Marshall Space Flight Center awarded a $139,000 follow-on contract to Martin Marietta Corp. to study a system for reclaiming unused propellant from Space Shuttle external fuel tanks and transferring it to an orbiting space station, Aerospace Daily reported. Martin Marietta Corp's New Orleans, Louisiana, manufacturing facility would perform the work on the preliminary design study. The contract followed one let in February 1984 and valued at $250,000 to examine the basic "propellant scavenging" concept.
The system under study would consist of two to four propellant collecting or scavenging tanks in an aft cargo carrier affixed to the rear of the Space Shuttle external tank. After Space Shuttle launch and cutoff of the main engines, residual liquid oxygen and liquid hydrogen would drain from the external tank into the collection tanks aided by a thrust system designed for zero-gravity conditions. Once filled with fuel, the scavenging tank assembly would separate from the aft cargo carrier as a self-contained, remote-controlled vehicle with its own propulsion system.
After the vehicle moved into position beside the space station, technicians aboard the station would send an orbital maneuvering vehicle (OMV) to bring it to the space station fuel depot for transfer of the reclaimed propellant to permanent tanks. When out of fuel, the scavenger vehicle would return to earth in the Space Shuttle cargo bay for reuse on later missions.
The proposed system would be capable of reclaiming and transporting up to 25,000 lb. of propellant per mission, depending on the Space Shuttle payload. Unused fuel on Space Shuttle missions to date had ranged from 9,500 to 28,300 lb. of the total 1.6 million lb. of propellant carried by the external fuel tank on each flight. It was currently estimated that the space station would require some 250,000 lb. of liquid hydrogen and liquid oxygen propellants each war.
Martin Marietta said the proposed system would result in reduced costs for transporting the cryogenic fuels to the space station; the company estimated the system could provide propellants at an average cost of approximately $350 per lb. NASA had studied other methods of scavenging fuel from the Space Shuttle external tank but found them to have a higher cost per lb. or to provide fewer opportunities for transporting the cryogenic fuels to the station. (A/D, July 12/85, 61)
The U.S. Air Force rolled out the C-5B today, the first B model of the free world's largest military cargo aircraft, the Air Force Systems Command Newsreview reported. Although it looked like a C-5A, the new C-5B had many improved features including state-of-the-art materials and avionics. It also had the new wings, which would boost the service life of the aircraft to 30,000 flight hours, that the Air Force was retrofitting to the A model.
The Air Force planned to buy 50 C-5Bs, nearly doubling its capability to airlift non-stop anywhere in the world large equipment such as the Army's 74-ton mobile scissors bridge, Abrams M-1 tanks, and helicopters. When the purchase of the C-5Bs was completed, the Air Force would be about 18 million-ton-miles per day short of its goal of 66-million-tons per day of outsized airlift capability, the minimum capability recommended in a 1981 Congressionally mandated mobility study. The Air Force planned to make up the difference by acquiring the C-17.
Four improved General Electric TF-39 engines, rated at 41,000 lb. of thrust each, powered the C-5B. The aircraft seated 75, and its seats were 30% lighter than the A model's, decreasing total aircraft weight by 725 lb and cutting fuel consumption by an estimated $13 million 9ver the life of the C-5B fleet.
The C-5B's 24 main landing gear wheels had carbon brake assemblies with multiple discs. More than 400 lb. lighter per aircraft, the new brakes doubled the life of the A model's beryllium system and should bring about an estimated 20-year savings of $20 million.
In October 1982 the Air Force's Aeronautical Systems Division had awarded a $50-million preliminary C-5B production contract to Lockheed-Georgia. Plans called for early September flight testing of the first production aircraft at Dobbins AFB, Georgia. The Air Force had contract options to buy 50 C-5Bs for $7.817 billion. (AFSC Newsreview, July 29/85, 1)
Arnold Engineering Development Center completed the fourth and final qualification test firing of the Payload Assist Module-D (PAM-D) II rocket motor, the Air Force Systems Command Newsreview reported. The PAM-D II featured increased propellant capacity (7200 lb.) over its predecessor, the PAM-D (4400 lb.), and could boost both military and commercial communications satellites into geosynchronous orbit about 22,300 miles above earth.
A Space Shuttle would deliver the motor and its payload into space at an altitude of 160 to 180 miles, where the PAM-D II satellite package, spinning at 30 to 85 rpm, would spring-eject from the orbiter's open bay doors.
At a safe distance from the orbiter, the PAM-D II, which served as a perigee kick motor, would ignite and propel its payload more than 22,000 miles higher. PAM-D II would then separate from the payload, which was positioned by its own apogee motors activated by signals from earth.
AEDC test-fired the motor in one of its high-altitude rocket development test cells at a simulated pressure altitude of approximately 100,000 feet while spinning it about its thrust axis at 70 rpm. Test objectives were to determine ballistic performance and to take plume (exhaust) radiation measurements, which were important in determining if the exhaust radiation would damage the motor case or satellite.
With the fourth test completed, the Air Force considered the motor ready for production and flight. Morton Thiokol's Wasatch Division was the rocket's manufacturer. NASA had tentatively scheduled PAM-D II's first flight for November 1985 aboard the Space Shuttle Challenger to place the RCA SATCOM satellite into orbit. (AFSC Newsreview, July 12/85, 7)
NASA scheduled the Space Shuttle Challenger to take today four high-tech cans each of Pepsi-Cola and Coca-Cola, the world's two largest-selling soft drinks, into orbit for the first time, the Washington Post reported. Stocking Challenger with both Coca-Cola and Pepsi-Cola resulted from a compromise reached after weeks of highly sensitive negotiations. NASA had not previously flown carbonated drinks in space because no containers were available to control and dispense carbonated liquids in zero gravity.
It took the companies more than two years to develop and test the cans. Pepsi-Cola said its can cost its supplier, Enviro-Spray, $14 million to develop. Pepsi-Cola filled its can with eight ounces of cola and a plastic pouch that expanded when chemicals were mixed inside it to create carbon dioxide gas, which then inflated the pouch and forced the beverage out. Coca-Cola's can was lined with a laminated plastic bag filled with cola that overlaid a second plastic bag containing carbon dioxide under 50 lb. of pressure. The carbon dioxide forced the cola out of the can. A drawback to both cans was that they must be drunk unchilled.
NASA retained the legal right to use whichever container worked best, the Washington Times reported, and to fill it with the drink of its choice. (W Post, July 12/85, A3; W Times, July 8/85, 3A)
Space Shuttle mission 51-F was aborted today at three seconds before liftoff when the orbiter Challenger's onboard computer automatically shut down the main engines, Spaceport News reported. Seconds after main engine start, main engine No. 2 lost redundancy to operate the chamber coolant valve. NASA's ground rule restricted launching without an operating backup system in that area of the main propulsion system. Although the valve did assume its proper position after a command from a backup system, the loss of redundancy resulted in a major component failure flag being sent to the orbiter's computers.
Challenger Commander Gordon Fullerton later thanked the Kennedy Space Center team on behalf of the crew, saying the team acted quickly and professionally and that at no time did the crew feel apprehensive. In answering a Washington Post reporter's question later, Fullerton said, "We all have mixed emotions here, but we're thankful the system worked the way it should. It was the longest three seconds I've ever experienced." Launch operations manager Thomas Utsman said that crews would strip parts of the malfunctioning engine and that engineers had identified four different parts that could have failed when they should have been pumping fuel from the hydrogen tank into the engine chamber.
When the liquid-fuel engines ignited, valves that fed fuel into the chambers were fully open so engines could attain speed instantly. Just before liftoff, the valves were partially closed to cool engines slightly and prevent too much fuel from entering the chamber. The valve on main engine No. 2 failed to close partially, signaling the computer to shut down the system.
The first Space Shuttle abort occurred June 26, 1984, when an onboard computer shut down two of Discovery's three engines four seconds before liftoff. That abort triggered an investigation that led to a complete overhaul of Discovery's main engines. NASA had to move Discovery back to the Vehicle Assembly Building where its cargo was removed and placed aboard another orbiter that flew into space two months later.
"We don't think the engine valve itself failed the way a valve failed the [other] time we had a launch abort," Space Shuttle program manager Robert Lindstrom said. "I really believe there's a fair likelihood we'll get off again in another week." The delay did have an impact on the mission's objectives. The infrared telescope in Challenger's cargo bay could be operated successfully only in a completely dark sky. Had the flight left on schedule, the sky would have been dark for most of the following seven days until a new moon.
NASA had scheduled the next Space Shuttle launch using the orbiter Discovery for August 24. It was not immediately clear how the Challenger's abort would affect that mission. (Spaceport News, July 19/85, 1; W Post, July 13/85, A3)
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