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Reportsnow indicate that the White House has pulled the plug on any further rescue orrepair efforts on the Hubble Space Telescope. This seems to be a direct resultof a blue ribbon panel's recommendation to abandon efforts to rescue Hubblewith a robotic system. All agreed thatwe are nowhere near being close to being able to build such a sophisticatedrobotic system in time to reach the Hubble before it fails, and that we do nothave a reasonable chance of success with no damage to Hubble. The quoted costs were quickly escalating andthere was no clear idea of how long it would take. In addition, it seemed that the canceledHubble 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 acompany to research the robotic repair system, Skycorp,a satellite company, had offered to create a solar-electric space tug, anion-rocket powered stage that, when launched to rendezvous with Hubble, dockwith the spacecraft and gradually move it into the ISS'sorbit, a major orbital plane change of about 30 degrees. (This could not be accomplished using achemical 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 andextend the lifetime of expensive Comsats. The vehicle would have been assembled at the space station manually dueto the large solar arrays needed for the ion engine.
Once in the ISS'splane, the Hubble's orbit would be lowered to match that of the space station. TheHubble could then be serviced directly by the crew, before or after visitingthe station, without needing to make a special trip, and the Hubble replacementparts would be able to be included on the regular shuttle manifest for theStation. This would have greatly reducedthe risk and cost of the repair, and would have left the Hubble in an orbitwhere 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 thatHubble 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, isthat they may not be ready before Hubble fails. An actual shuttle servicingmission is the only method that we are sure could be ready in time.
Whatis at stake if the Hubble is not serviced on time? It is likely to fail during the 2007-8 timeperiod. Either the batteries or theattitude control gyros will fail, eventually leaving it either dead or unableto do any research. (It can survive withno science with one gyro but must have working batteries for use duringnighttime passes.) Once sufficientfailures have occurred, lack of heat and the resulting thermal damage toelectronics will quickly ensue, and then the telescope could not practically berecovered. Without a servicing mission,the two new instruments, which would greatly enhance the Hubble, will never beinstalled and used.
TheHubble is the only large visible light and ultra-violet space telescope we havein operation. Many of the wavelengths itreceives cannot be seen on the ground at all. The same is true of the current Spitzer Telescope, which sees using mid-rangeand thermal Infrared frequencies. The James Webb Space Telescope will coverfar-red, optical infrared and thermal infra-red wavelengths, and will probablynot be ready for launch and use until about 2012. This would leave us withoutany Visible or Ultra-violet space telescope for about 5 years. Large ground-based telescopes may have morelight-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).
Largeground scopes newly outfitted with interferometery and adaptive optics hardwareand software can rival the Hubble's resolution only in one very small patch ofsky at a time. The Hubble can takephotos with comparable resolution over a much wider field of view. Hubble also has an ability to stare at oneobject in space for many hours or days, which no ground-based telescope canmatch. There is little question thatdollar for dollar, Hubble is one of the most important and productive scientificinstruments the United States' possess, and it cannot be quicklyreplaced.
Astronomyis partly a science of serendipity. Important objects and events can appear suddenly and may as quicklyvanish from sight. At any time, a newsupernova could appear in our galaxy -- we are statistically overdue forone. If one were to appear just afterHubble fails and before any replacement was ready, astronomers would never letus hear the end of it. There also is a general feeling in the science communitythat the current administration does not care much about pure science. If the Hubble was to be discarded now,feelings would run even higher. TheHubble is also very popular among the public, and a significant political backlashcould be expected there also if it is allowed to fail.
NSSmembers, interested in human exploration and settlement of space, usually takethe position that Science is the servant of Mankind, not the other wayaround. However, as strong supporters ofscience, we have to turn the cheek when groups of scientists (like the AmericanPhysical Society), take a narrow-minded and self-serving stand against spaceexploration, since we want science to progress too. While I personally agree strongly with the policyof a Return to Exploration supported by the Bush Administration, I do notwant to see basic science capabilities eroded either.
What should be done? If the media backlash driven by the public and thescientific community gets loud enough, the Administration might feel enough pressureto bypass NASA and conduct its own search for an independent, inexpensivesolution, such as the one mentioned above. If all efforts fail to preserve theHubble, an effort should be made to fund and rapidly create a cheaperreplacement, built to accommodate the two new Hubble instruments, which wouldoperate a few hundred miles ahead of or behind the space station, allowingfrequent, cheap servicing missions with whatever vehicle succeeds the Shuttle.In addition, NASA, the European Space Agency, Japan and any other interestedcountries should create an orbiting observatory consortium, which would sharecosts and benefits of a set of permanent, upgradeable orbiting observatoriesintended to cover all areas of the electromagnetic spectrum. Access to spectrumranges, (especially those blocked by the atmosphere), should now be guaranteedto science, just as access to weather information is guaranteed to localweather bureaus.
John KStrickland, Jr. is on the board of the National Space Society.