January 1983:space activities report

ASTEROID MISSION STUDIES

Asteroids provide a unique sample of the material which may hold significant clues to the way in which our Solar System was formed and evolved. RCA Astro-Electronics have been studying the feasibility of modifying their Tiros weather satellite to carry out a rendezvous mission with a near-Earth asteroid.

"Fully understanding the asteroids and their implications to Solar System physics requires an orderly study of several different types of bodies, by putting satellites in asteroid orbits.” said Dr. Ronald Maehl, Manager of Scientific Programs for RCA Astro-Electronics. He noted that this approach would set the stage for multiple rendezvous missions with main belt asteroids between the orbits of Mars and Jupiter.

The three-month study, performed under contract from the Jet Propulsion Laboratory,-examined a mission payload including imagers to record the size, shape and reflective characteristics of the asteroid, as well as other sophisticated instruments to define additional asteroid properties and the near-asteroid environment.

NEW SHUTTLE TANKS

A major milestone in the Space Shuttle programme was reached on 10 September when the first lightweight External Tank (LWT-1) was rolled out of the manufacturing plant at NASA's Michoud Assembly Facility in New Orleans.

The large brown External Tank carries the super-cold liquid oxygen and hydrogen propellants for the Space Shuttle Main Engines, and acts as the structural “backbone” of the Shuttle vehicle. The tank’s three major components are an oxygen tank, a hydrogen tank and a collar-like intertank which connects the two propellant tanks and houses the entire structure’s instrumentation.

At 71,000 lb (32,000 kg), LWT-1 is about 7.000 lb (3,200 kg) lighter than the External Tank used for the Shuttle’s maiden flight in April 1981. The reduced weight will provide the Shuttle with extra payload-carrying capability almost equal to the weight reduction (because the Tank travels nearly all of the way into orbit). According to James Odom, manager of the External Tank Project Office at the Marshall Space Flight Center, the reduction was accomplished by eliminating portions of stringers (structural stiffeners running the length of the hydrogen tank), using fewer stiffener rings and by modifying major frames in the hydrogen tank. Also, large portions of the tank were milled differently to reduce thickness and weight; and the weight of the aft Solid Rocket Booster attachments was reduced by using a stronger, yet lighter and less expensive titanium alloy.

"Several hundred pounds was also eliminated by deleting an anti-geyser line.” said Odom. This line acted as a built-in refrigeration system, keeping liquid oxygen at its super-cold temperature while filling the oxygen tank prior to launch. NASA officials decided to remove the line after assessing propellant loading data from ground tests and the first few Shuttle missions. Although most of the Tank’s alterations will not be apparent to the casual observer, one change is already obvious: 600 lb (270 kg) of white latex paint was eliminated from the outer skin before the third flight. After analysing data from the first mission, NASA officials determined that the thermal protection system would adequately protect the Tank without the paint.

After “rollout”, the tank was loaded aboard a NASA barge for shipment to the Kennedy Space Center where it was to be prepared for the sixth mission.

SOLAR ARRAY EXPERIMENT

A 105 ft (52 m)-long experimental solar array has been successfully extended and retracted during initial testing in preparation for flight aboard the Space Shuttle in 1984.- The wing is part of NASA’s Solar Array Flight Experiment, developed for NASA’s Marshall Space Flight Center. The experiment is undergoing extensive testing by its manufacturer, Lockheed, before acceptance by the Marshall Center.

The flight experiment is helping to develop technology necessary for using solar arrays to produce large amounts of electrical power from sunlight in space. The additional power could significantly expand space-based mission operations by meeting the high energy, long term requirements of space experiments and space platforms.

One of the major objectives of the recent tests was to check the extension/retraction system that will deploy the wing from its packaged configuration aboard the Shuttle during the flight. During launch, the accordion-like array wing, 105 ft (52 m) long and 15.5 ft (4.1 m) wide, will be folded in the Orbiter’s cargo bay in a package less than 4 in (10 cm) thick. Once on orbit, it will be extended to its full length and retracted several times to verify the structural and dynamic characteristics. A coilable, extension mast will provide the mechanism needed to extend, retract and hold the array in a planar configuration.

This solar array departs from rigid metal structures currently used on long-life spacecraft. Instead, it is made of lightweight, flexible plastic (Kapton) and contains wrap-around contact solar cells that are welded directly to the array blanket. This printed circuit approach eliminates heavy adhesives and allows greater flexibility during handling and during extension and retraction.

To minimise costs, the experiment will contain only one wing panel with live solar cells. By contrast, an array with all 84 panels populated with solar cells could convert energy from the Sun to produce 12.5 kilowatts of power. The experimental wing can provide 66 watts per kilogram compared with 20 watts per kilogram in present systems. With current high efficiency cells, up to 75 watts per kilogram are feasible using the same structural concepts.

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THE ASTRONAUTS OF STS-6

Paul Joseph Weitz

Paul Weitz was born in Erie, Pennsylvania on 25 July, 1932. He was educated in Pennsylvania and received a degree in aeronautical engineering from the state university in 1954. He entered the US Navy that same year and was awarded his wings in September 1956. Between June 1962 and June 1964 Weitz attended the USN postgraduate school and was awarded a masters degree in aeronautical engineering. He retired from the USN in 1976.

Selected as one of 19 group 5 pilot astronauts in 1966, he was a member of the support crew for Apollo 12. He flew as Skylab 2 pilot in May and June 1973, spending 28 days in space and logging 2 hours 11 minutes in EVA outside the space station. Weitz was assigned to Shuttle development in 1975, being concerned with crew station hardware and Earth resources studies. In 1977 he headed the design support group in the Astronaut Office at the Johnson Space Center and by April 1979 he was responsible for coordination of the technical effort in Shuttle development. He was named as Commander of STS-6, the first flight of the second Orbiter, in December 1981.

Karol Joseph Bobko

Karol Bobko was born in New York on 23 December 1937. He received a bachelor of science degree from the USAF Academy in 1959 and was awarded wings in 1960.

In 1965/66 he attended the Aerospace Research Pilots School at Edwards Air Force Base and was selected for the Manned Orbiting Laboratory project in June 1966. He transferred to NASA in August 1969.

In January 1973 Bobko was assigned to the Apollo Soyuz Test Project and was a support crew member until July 1975. He was assigned to the Shuttle landing test programme in 1976 and served alternately as CapCom and primary chase pilot. During the first weeks of 1979 he conducted ground tests and checkouts with Columbia. He was named as Pilot for STS-6 in December 1981.

Donald Herod Peterson

Don Peterson was born on 22 October 1933 in Winona, Mississippi. He graduated from West Point with a bachelor of science degree in 1955 and in 1962 he obtained a masters degree in nuclear engineering from the Air Force Institute of Technology in Ohio. He was selected for the MOL programme in 1967, serving as astronaut flight member until its cancellation in 1969.

Selected as one of seven group 7 former MOL astronauts by NASA in the autumn of 1969.he was assigned as support astronaut for Apollo and acted as a CapCom for Apollo 16. He moved on to Shuttle development in 1975, being concerned with navigation, communications and tracking hardware, as well as reaction control and orbital manoeuvring hardware. In April 1979 Peterson was a member of the Orbital Flight Test mission group of the Astronaut Office responsible for engineering support and safety assessment. He retired from the USAF in 1980 and was named as a Mission Specialist for STS-6 in December 1981.

Franklin Story Musgrave

Story Musgrave was born in Boston on 19 August 1935. He gained the following degrees between 1958 and 1979: B.Sc. in mathematics and statistics (1958); Masters in businessadminis- tration and computer programming (1959); B.A. in chemistry (1960); Doctorate in medicine (1964); M.Sc. in physiology and biophysics (1966); and Doctorate in physiology/biophysics, with a minor in aeronautical engineering (1979).

Musgrave was selected for the astronaut programme in August 1967. He subsequently took part in the Skylab programme, serving as a backup for Skylabs 1 and 2 and as CapCom fot Skylab 3. He was mission specialist for the first two Spacelab mission simulations in 1974 and 1976. In 1975 he participated in the development of Shuttle EVA equipment. In addition to his astronaut duties, Musgrave has continued clinical and scientific training as a part-time surgeon and as a part-time professor of physiology'and biophysics. He has writ¬ ten over 30 scientific papers, logged over 10,000 flying hours and made over'330 free fall parachute drops. He was named as a Mission Specialist for STS-6 in December 1981.