henry@zoo.toronto.edu (Henry Spencer) (08/20/90)
Editorial commenting that the history of HST's mirror problems can be
traced pretty easily to what Perkin-Elmer managers told Congress in
1983: "Our problems resulted from a combination of underestimating
technical challenges and the cumulative effect of funding shortages.
This funding shortfall in turn resulted in elimination of development
testing, cutbacks on critical support hardware, interruption in certain
developmental efforts and general operational inefficiencies."
Space-station preliminary design reviews underway, involving about 500
people. [!] Design is considered about 20% complete. [Well, it's only
been eight years, after all... :-[ ]
US government and industry to supply Japan with spare parts after fire
damage to a first-stage engine endangers the launch date for Japan's
ERS-1 earth-resources satellite. [The Japanese H-1 launcher is partly
a Delta derivative.]
Excrement hits fan for Hubble Telescope as mirror flaw is discovered.
The Wide Field / Planetary Camera is considered useless. [It now appears
that this may have been slightly pessimistic.] The Faint Object Camera
will be no better than ground instruments, except in the ultraviolet,
barring the possibility of computerized image enhancement. The High-
Resolution Spectrograph is primarily an ultraviolet instrument, and
its users are overjoyed at getting more observing time; the only impact
on it is difficulty in working in very crowded fields of view where
many stars are very close to each other. The Faint Object Spectrograph
is likewise largely unaffected except for crowded-field work, although
there had been plans for coordinated FOS-FOC work that may be hampered
by the FOC's problems. The High Speed Photometer will be able to do
about 50% of its planned work, the parts losing out being those that
need a high signal-to-noise ratio. The Fine Guidance Sensor Astrometry
work, including search for planets around nearby stars, should be nearly
unaffected.
Columbia's hydrogen leak forces replacement of major plumbing components
with ones borrowed from Endeavour.
Commercial Titan successfully launches another Intelsat VI, with various
precautions in place to avoid a repetition of the stranding of the last
one. Pad 40 now goes offline for two years for renovations, with activity
to resume with the launch of Mars Observer in Sept 1992 (the only other
firm customer for CT at this time). Martin Marietta has decided to focus
CT marketing on US government customers in future.
House kills Moon/Mars funding, despite a general budget increase for NASA
overall. Various constraints have been imposed on the station, including
availability of the full 75kW of power before any non-US modules go up,
and placement of life-science centrifuge equipment and animal holding
cages elsewhere than the US microgravity lab.
Motorola proposes a $2.3G light-satellite network to establish essentially
a global cellular-telephone system. The "Iridium" system would use 77
315kg satellites in low polar orbits. The bulk of them would go up in
clusters on medium boosters, with individual replacement birds launched
as needed by small boosters like Pegasus. The eventual hope is to launch
a replacement satellite within 36 hours of a failure. The satellites use
phased-array antennas to project multiple coverage cells onto the Earth,
and relay calls among themselves to make long-haul connections. The
intent is to have mobile phones that automatically select a ground-based
cellular network when available (since it will probably be cheaper) and
resort to Iridium in remote areas and during disasters. The low orbit
calls for many satellites, but minimizes transmitter power and eliminates
the delays and echos of Clarke-orbit phone connections. Motorola would
prefer to just build the satellites and ground equipment, but will join
a financing consortium if necessary; negotiations with Inmarsat, American
Mobile Satellite Corp, and Telesat Mobile Inc (of Canada) are underway.
The political and regulatory obstacles will be the big ones.
Relay Mirror Experiment satellite successfully bounces a laser beam from
the Maui Optical Observatory to a target at Kihei.
--
Committees do harm merely by existing. | Henry Spencer at U of Toronto Zoology
-Freeman Dyson | henry@zoo.toronto.edu utzoo!henry