June 1982:space activities report

ARIANE DECLARED OPERATIONAL

On 25 January representatives of the states participating in ESA's Ariane programme unanimously declared the launcher to be qualified and fully operational. On this occasion, the Member State representatives warmly congratulated all those in the Agency, the Centre National d’Etudes Spatiales (CNES) and European industry who had contributed to this impressive achievement.

The initial analysis of the fourth and final Ariane test flight last December confirmed that the launcher performed as expected. Ariane L04 injected the European Maritime Communications Satellite (MARECS 1) into a transfer orbit whose apogee of 36,051 km was only 5 km off its planned value. The Viking engines on the first and second stagfes performed as planned, thus confirming that the vibration problem encoun¬ tered on the second test flight had been eliminated successfully.

L04 was the first launch with representative operational constraints. In order to ensure injection of the spacecraft into an optimal orbit, the launch window was limited to only 45 minutes per day. After a 24-hour postponement (due to a mechanical problem with the liquid oxygen feed valve plates on the third stage), the 29 hr 20 min countdown ticked away without a single interruption, leading to a launch at the first second of the 45 minute window. As on the third test flight, a series of manoeuvres of the third stage, reproducing the injection into orbit of two different satellites on a single launch, was successfully carried out.

The first series of seven operational launches, known as the promotion series, will now be carried out under ESA auspices. Subsequently, responsibility for the marketing, manufacture and launching of Ariane will be handed over to Arianespace, a private company set up for this purpose. The promotion series includes four launches in 1982, with three in 1983.

EUROPEAN PAYLOAD SPECIALISTS

European Space Agency Spacelab payload specialists Dr. Wubbo Ockels of the Netherlands and Dr. Ulf Merbold of West Germany arrived at the Marshall Space Flight Center, Huntsville in January to complete their training for the first Spacelab mission, presently scheduled for September 1983. Ockels, Merbold and two other payload specialists. Dr.Michael Lampton and Dr. Byron Lichtenberg of the United States, have been in training for the mission since August 1978. The two Europeans moved to the United States because > training for the flight has intensified.

Of the four payload specialists training for the first mission, one American and one European will actually go into space. The other two will operate ground-based support equipment and support the pair in orbit.

Spacelab 1 is to be a seven-day, joint NASA/ESA mission during which some 70 investigations in five different disciplines will be conducted.

ORBITING TELESCOPE STUDIES

The Perkin-Elmer Corporation has been selected by NASA's Ames Research Center in California to conduct an in-depth study of segmented mirror technology. The study is the first step in the development of giant mirror systems, 50 to 100 ft in diameter, which will be deployed by the Space Shuttle in orbit hundreds of miles above the Earth. These large mirrors will be formed by the assembly of many smaller mirrors (segments).

To prepare for the astronomical space projects envisaged for the 1990’s, objective mirrors such as the Large Deployable Reflector, which will operate over the wavelength range from 2 to 1000 m, will be required. NASA is currently investigating the optimum mirror segment material and state-of-the-art fabrication techniques suitable for these assemblies. Perkin-Elmer will devise and evaluate various technical approaches for large precision mirrors that will be dramatically lighter and more easily fabricated than today’s most advanced concepts.

"Segmented mirrors will eliminate the necessity of grinding large heavy mirrors in one piece and will permit us to design deployable mirrors that will fit into the present Space Shuttle cargo bay," said John Russo, Manager of the Science and Applications Department at Perkin-Elmer.

One critical issue being addressed is how large and/or flexible a mirror segment can be and remain sufficiently stable so that active figure (shape) sensing and control is not required to compensate for thermal and gravitational distortions. How to economically produce a large number of matching off-axis parabolas is another aspect that will receive considerable attention.

Space astronomy optical systems of larger size and extended capabilities will become possible when the goals of the Segmented Mirror Technology Study are achieved. NASA’s present plans combine the infrared and submillimeter radio astronomy disciplines in a design for a collector system comprising a primary mirror ranging from approximately 15 m (50 ft) in diameter to a larger 30 m mirror. The 15 m telescope will be deployable in space as a detached, free-flying payload. The larger 30 m concept will require the telescope system to be assembled in space because its projected size precludes automatic deployment.

STS-5 PAYLOADS

The US space communications company Satellite Business Systems expects its third spacecraft to enter orbit in November aboard STS-5, the first operational mission of the Shuttle system. Telesat of Canada has committed a satellite to the same mission.

The importance of using a reusable launching system can be appreciated by looking at the cost differences between this launch and previous SBS flights. The company paid NASA $23 million for each of two Delta launches and related services, but the Shuttle’s ride into orbit will cost about $8 million, according to Lawrence A. Weekley of SBS.

“Our spacecraft are designed to launch via Delta or the Shuttle," Weekley explained. “The dual launch compatibility is achieved with a payload assist module (PAM) which acts as a third stage. It is integrated into our spacecraft payload. We procure PAM as part of our spacecraft contract with Hughes Aircraft Co. Hughes subcontracts with McDonnell Douglas for PAM manufacture. For either Delta or Shuttle, SBS opted to contract with NASA for launch into synchronous transfer orbit; we assume responsibility for PAM and apogee motor manoeuvres.”