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Reports
now indicate that the White House has pulled the plug on any further rescue or
repair efforts on the Hubble Space Telescope. This seems to be a direct result
of a blue ribbon panel's recommendation to abandon efforts to rescue Hubble
with a robotic system. All agreed that
we are nowhere near being close to being able to build such a sophisticated
robotic system in time to reach the Hubble before it fails, and that we do not
have a reasonable chance of success with no damage to Hubble. The quoted costs were quickly escalating and
there was no clear idea of how long it would take. In addition, it seemed that the canceled
Hubble servicing mission was priced at the full cost of a shuttle mission
(making the total cost seem much higher), while the International Space Station
(ISS) servicing missions do not seem to include shuttle costs.
Before the recent selection of a
company to research the robotic repair system, Skycorp,
a satellite company, had offered to create a solar-electric space tug, an
ion-rocket powered stage that, when launched to rendezvous with Hubble, dock
with the spacecraft and gradually move it into the ISS's
orbit, a major orbital plane change of about 30 degrees. (This could not be accomplished using a
chemical stage.) As noted by Dennis Wingo, author and founder of Skycorp,
about a year ago, a similar system is being developed by industry to rescue and
extend the lifetime of expensive Comsats.
The vehicle would have been assembled at the space station manually due
to the large solar arrays needed for the ion engine.
Once in the ISS's
plane, the Hubble's orbit would be lowered to match that of the space station. The
Hubble could then be serviced directly by the crew, before or after visiting
the station, without needing to make a special trip, and the Hubble replacement
parts would be able to be included on the regular shuttle manifest for the
Station. This would have greatly reduced
the risk and cost of the repair, and would have left the Hubble in an orbit
where it could inexpensively be serviced in the same fashion again. NASA sidetracked the
whole idea, apparently due fears of their inexperience with in-orbit assembly,
in favor of another very expensive, ($2-3 billion) and very technically risky
endeavor (the robotic mission).
Since NASA itself insists that
Hubble will soon have to be de-orbited by a similar docking-capable vehicle,
their attitude makes no sense. The drawback to this, like most other plans, is
that they may not be ready before Hubble fails. An actual shuttle servicing
mission is the only method that we are sure could be ready in time.
What
is at stake if the Hubble is not serviced on time? It is likely to fail during the 2007-8 time
period. Either the batteries or the
attitude control gyros will fail, eventually leaving it either dead or unable
to do any research. (It can survive with
no science with one gyro but must have working batteries for use during
nighttime passes.) Once sufficient
failures have occurred, lack of heat and the resulting thermal damage to
electronics will quickly ensue, and then the telescope could not practically be
recovered. Without a servicing mission,
the two new instruments, which would greatly enhance the Hubble, will never be
installed and used.
The
Hubble is the only large visible light and ultra-violet space telescope we have
in operation. Many of the wavelengths it
receives cannot be seen on the ground at all.
The same is true of the current Spitzer Telescope, which sees using mid-range
and thermal Infrared frequencies. The James Webb Space Telescope will cover
far-red, optical infrared and thermal infra-red wavelengths, and will probably
not be ready for launch and use until about 2012. This would leave us without
any Visible or Ultra-violet space telescope for about 5 years. Large ground-based telescopes may have more
light-gathering power than Hubble, but they cannot see many of the very faint,
deep sky objects due to atmospheric sky glow.
(Their large optics concentrates the glow, too).
Large
ground scopes newly outfitted with interferometery and adaptive optics hardware
and software can rival the Hubble's resolution only in one very small patch of
sky at a time. The Hubble can take
photos with comparable resolution over a much wider field of view. Hubble also has an ability to stare at one
object in space for many hours or days, which no ground-based telescope can
match. There is little question that
dollar for dollar, Hubble is one of the most important and productive scientific
instruments the United
States' possess, and it cannot be quickly
replaced.
Astronomy
is partly a science of serendipity.
Important objects and events can appear suddenly and may as quickly
vanish from sight. At any time, a new
supernova could appear in our galaxy -- we are statistically overdue for
one. If one were to appear just after
Hubble fails and before any replacement was ready, astronomers would never let
us hear the end of it. There also is a general feeling in the science community
that the current administration does not care much about pure science. If the Hubble was to be discarded now,
feelings would run even higher. The
Hubble is also very popular among the public, and a significant political backlash
could be expected there also if it is allowed to fail.
NSS
members, interested in human exploration and settlement of space, usually take
the position that Science is the servant of Mankind, not the other way
around. However, as strong supporters of
science, we have to turn the cheek when groups of scientists (like the American
Physical Society), take a narrow-minded and self-serving stand against space
exploration, since we want science to progress too. While I personally agree strongly with the policy
of a Return to Exploration supported by the Bush Administration, I do not
want to see basic science capabilities eroded either.
What should be done? If the media backlash driven by the public and the
scientific community gets loud enough, the Administration might feel enough pressure
to bypass NASA and conduct its own search for an independent, inexpensive
solution, such as the one mentioned above. If all efforts fail to preserve the
Hubble, an effort should be made to fund and rapidly create a cheaper
replacement, built to accommodate the two new Hubble instruments, which would
operate a few hundred miles ahead of or behind the space station, allowing
frequent, cheap servicing missions with whatever vehicle succeeds the Shuttle.
In addition, NASA, the European Space Agency, Japan and any other interested
countries should create an orbiting observatory consortium, which would share
costs and benefits of a set of permanent, upgradeable orbiting observatories
intended to cover all areas of the electromagnetic spectrum. Access to spectrum
ranges, (especially those blocked by the atmosphere), should now be guaranteed
to science, just as access to weather information is guaranteed to local
weather bureaus.
John K
Strickland, Jr. is on the board of the National Space Society.