Europe's Space Telescope Keeps Going

Washington DC – July 9, 1997 – European Space Agency officials are saying that
their orbiting space telescope has passed the 18-month point in its space
“lifetime” on orbit with all systems running successfully, SpaceCast has
learned from industry sources.

The Infrared Space Observatory (ISO), launched November 17th 1995, is
believed to have another 10 months ahead of it to continue processing space
data. Built for ESA by the French aerospace contractor Aeropatiale, the
telescope is collecting data in space of infrared astronomy observations.
The telescope is making studies in the infrared wavelengths between three
to 200 microns.

SpaceCast has learned that the greatest concerns of ESA scientists, that
the cooling system for the telescope would not continue to keep the optics
at very low temperature, and that the spacecraft’s pointing system would
fail in the latter stages of the mission, have not been realized. By
keeping the optics cold, heat from other stars can be registered.
Aerospatiale engineers achieved this by placing the instrument package
inside a “cryostat”, a vacuum structure which contains 2250 liters of
supercold liquid helium The helium keeps the optical lens at about -270C.
Officials report that the temperature of this helium “bath” remains stable
after 18 months in space.

The spacecraft’s pointing system remains on target, with a pointing
accuracy of 0.5 arc second. The spacecraft onboard guidance, and autonomous
operating software is also reported as healthy. As a result of the
telescope’s robustness, space officials are believed ready to extend the
astronomical targets that the telescope will observe to a new as yet un
accessed group.