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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.