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.”