November 1982:space activities report

LAUNCHER STUDIES

Under contract with the NASA Marshall Space Flight Center in Huntsville, Alabama, Boeing Aerospace engineers are performing preliminary design work on a proposed Shuttle-Derived Cargo Launch Vehicle. This unmanned vehicle would serve as an extension of the Space Shuttle, placing payloads too large for the Shuttle into orbit. It would also allow the Shuttle to be used more frequently for critical missions requiring manned operations and longer time in orbit. Boeing is trying to minimise development risk, cost and time by using proven Space Shuttle flight hardware and technology.

The study’s objective is to provide NASA with the technical and economic data necessary to evaluate such a vehicle. Engineers will further define costs, payload manifesting, various missions and how cargo could be divided between the Shuttle and the derivative vehicle.

The basic design concept consists of the Space Shuttle main engine and a shortened Shuttle External Tank which, together, act as the core stage. Two shortened Space Shuttle Solid Rocket Boosters would be mounted on each side of this stage. The large payload and a kick stage would be placed above the core within a canister shroud.

During ascent, the Solid Rocket Boosters would be separated from the External Tank and payload at about 177,000 ft (54 km). The boosters would be recovered by the same means as the Shuttle. After reaching ma'in engine cutoff at about 160 nautical miles (300 km), the core stage would be jettisoned into the ocean. The kick stage would then provide the final insertion into low Earth orbit at about 150 nautical miles (280 km). Recovery of the Shuttle engine and the kick stage by a Shuttle orbiter will be considered, Using the Shuttle launch facilities, the vehicle would be able to place payloads into orbit weighing up to 87,000 lb (39,500 kg).

For payloads with high-orbit destinations, an upper stage vehicle would replace the kick stage. After main engine cutoff, the upper stage would take the payload to a higher orbit such as geosynchronous orbit, some 22,300 miles (36,000 km) above the Earth.

On all missions, the proposed Shuttle-Derived Cargo Launch Vehicle would be guided and controlled during ascent by the avionics package of the upper or kick stage.

ARIANE SCHEDULE

L6

Nov 82

Exosat

L7

Jan 83

ECS 1 & Oscar 9B

L8

Mar 83

Intelsat 5 F7

L9

May 83

Intelsat 5 F8

L10

July 83

ECS 2 or Telecom 1A or Intelsat 5 F9

L11

Oct 83

Intelsat 5 F9 or ECS 2 & Telecom 1A or 1B

L12

Nov 83

Westar 6 & Telecom 1A or 1B or ECS 2

ECS is the European communications satellite, while Oscar is an amateur craft designed to replace the satellite lost in the Ariane L02 launch failure. The L10 payload will depend on which of those listed is ready first, and L11 could use either an Ariane I (for Intelsat 5 F9) or Ariane II (for ECS 2 and Telecom). L12 will use the more powerful II version to launch two communications satellites.

ARIANE CONTRACT

A contract has been awarded to Marconi Space and Defence Systems to supply flight programs for the first Ariane production vehicles. This follows the successful completion of the Ariane development phase when the vehicles were controlled from the moment of lift-off by programs developed and produced by Marconi. The Marconi Ariane software team has recently completed a program development contract for an improved Ariane and is likely to be involved in similar development work for future versions of the vehicle during the next decade.

After launch, Ariane is autonomous except for range safety considerations. The flight program guides the launcher along an optimum trajectory into the required orbit. This involves several main processes:

1. Inertial navigation, using inputs from the inertial platform, to calculate vehicle position and velocity.

2. Guidance computation to correct the remainder of the trajectory, into the required orbit, and determine the current attitude of the vehicle.

3. Sequencing control of vehicle systems throughout the flight, including stage, fairing and payload separation.

After Ariane has been injected into the correct orbit, the program controls payload orientation and spin. The program for a particular mission is produced by combining a reference program with the appropriate flight plan and orbit data base. Testing is carried out by running the program in an Ariane on-board computer, interfaced with a scientific computer which contains a mathematical representation of the launch vehicle’s performance characteristics.

UNUSUAL MILITARY SATELLITE

Earlier this year, on 21 January, the US Air Force launched its 62nd Titan 3B. Its payload entered a 143 by 537 km orbit, with a period of 91.40 minutes and an inclination of 97.32°, writes Anthony Kenden. Most observers of the US military space programme quickly classed it as a routine high resolution "close look” photographic reconnaissance satellite because of its tell-tale low perigee and Sun-synchronous inclination. However, subsequent manoeuvres showed it to be an unusual mission.

The low perigees used by close look satellites mean that they experience considerable atmospheric drag, forcing them to make daily manoeuvres to counter orbital decay. A day after launch, the new satellite (1982-06A) manoeuvred, but the resulting orbit was much higher than those used by close look satellites. It was the first indication that the satellite was not all that it had originally seemed. It was to surprise observers again and again over the next four months.

1982-06A’s new orbit had a perigee of 553 km and an apogee of 645 km, with a period of 96.73 minutes. At this altitude it showed virtually no atmospheric decay. Was it simply a close look satellite in a parking orbit waiting to be called down to active service when the need arose? The answer was shown to be "no” on 29 January, when 1982-06A manoeuvred again, raising its perigee to 582 km. By 9 March it had raised its orbit a further six times, resulting in a path of 622 by 655 km, with a period of 97.55 minutes.

After a week of this, 1982-06A manoeuvred again, but this time lowering its orbit. Five days later it released three objects into their own orbits. The main satellite then continued to lower its path, until by 22 April it ranged from 601 to 613 km. Five days later a second relatively large manoeuvre was made, raising the orbit to 633 by 645 km, and after another six days a fourth object appeared.

Having manoeuvred 16 times in 96 days, 1982-06A now became inactive. For 26 days it stayed in this high orbit, decaying slightly but showing no signs of any manoeuvring. Finally, on 23 May, it fired its engine for the last time and pushed itself out of orbit. It had been in space for 122 days.

There are no obvious clues as to what 1982-06A was actually doing, either from its orbital behaviour or from reports in the press, but it is possible to make some intelligent guesses. Examining all the types of. US military space activities and eliminating those for which current and future programmes have been well publicised leaves photo reconnaissance, electronic intelligence and ocean surveillance as possibilities. Of these, Ihe most likely appears to be to test systems for the new advanced KH-11 photo reconnaissance satellite, due to enter service in 1984.