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On July 22, 2008, the crew members of the upcoming STS-125 mission—which includes two spacewalking teams, one led by John Grunsfeld and the other led by Mike Massimino (see bios below)—answered selected viewer questions about their Space Shuttle mission to repair the Hubble Space Telescope. Please note we are no longer accepting questions, but see the features on our Saving Hubble page as well as our Links & Books section for more information. 
Dr. John M. Grunsfeld (left) is a veteran of four spaceflights, including
two to the Hubble Space Telescope, in 1999 and 2002. (Mike Massimino, right,
was also aboard the latter flight.) All told, Grunsfeld has logged over 45 days
in space, including five spacewalks; on the upcoming Space Shuttle mission to
the Hubble, he will be in charge of such extravehicular activities, or EVAs.
Grunsfeld has degrees in physics from M.I.T. (B.S.) and the University of
Chicago (M.S. and Ph.D.). He has studied binary pulsars and energetic X-ray and
gamma-ray sources using the NASA Compton Gamma Ray Observatory, X-ray astronomy
satellites, radio telescopes, and optical telescopes, including the Hubble. Grunsfeld, who is married with two children, was a member of the NOVA team
that climbed Denali.
Q: You've mentioned that one of the main dangers of this mission is the possibility that the circuit boards may tear a glove as you work. How did NASA choose the materials for the exterior layer of the gloves? Were they redesigned with the hazards of this mission in mind? A: The EVA gloves we are using are the latest "Phase VI" gloves, which are really great to work in. They are very flexible and offer us rather good dexterity. We have not modified the gloves specifically for this mission, but instead have opted to build tools that allow us to handle the cards without having to grab them with our hands. We need these tools regardless, as they may be hard to pull out. On the index finger and thumb of our gloves there is a small patch that has been installed to help with wear issues that have been identified on the International Space Station. Q: Terrific set of fascinating topics. Qtn: Why don't we just build a new Hubble $1.5 billion instead of risking lives for only 5 to 10 yrs? A: The interesting fact is that after this mission, Hubble will have the most capability of its lifetime. It's almost as if we are making a new telescope. The cost and time to make a new Hubble would be substantially more than the original price and would likely take more than five years to accomplish. By using the highly capable Space Shuttle and humans to do the upgrades we have gotten much more life and capability out of Hubble than would be possible if we tried to make a new Hubble whenever there is a problem. I am a strong believer in space exploration and agree it's only worth risking lives for something important. The science Hubble produces is that important. Q: Why doesn't NASA simply replace Hubble instead of this very risky repair operation? Is money the only reason? It seems to me like they're trying to keep a 1970 Volvo roadworthy!!! A: Even though Hubble has been on orbit for 18 years, it's hardly old. By using the best combination of skill of folks on the ground and those of astronauts, NASA has been able to reinvent Hubble each time it visits the telescope. This has resulted in far more science return and discoveries than would be possible if we only were able to launch a Hubble-type telescope every decade or so. The amazing fact is that after the STS-125 mission, Hubble will for the first time have a full complement of science instruments and will be orders of magnitude more powerful than the original telescope as launched. Q: Why not just use a core drill, in the case of a stripped screw on the mission? A: We do have a special drill in case of a stripped screw, which will hold the head and drill out the core. Q: When Hubble is eventually succeeded by the James Webb Space Telescope, will we be at a loss for not having an optical/visible space telescope? That is, are there any advantages to the Hubble telescope that infrared and radio telescopes are lacking? Also, are there any plans for another visible-light (optical) space telescope? Thank you. A: The hope is that we will have some overlap between James Webb and Hubble. This would be the best case for science. There are many reasons to have both optical/UV coverage and IR coverage for astronomy. These wavelength ranges often complement each other, so that James Webb may discover something that Hubble can follow up with or vice versa. Several groups of astronomers are designing possible UV/Vis telescopes to succeed Hubble. Q: About the glare on the capture device, why not have a variable output lamp on the tool? Good luck. A: We do have a high-beam and a low-beam on the Mini-Power Tool. Hopefully this will be sufficient. Q: Dear Sir, On the Hubble story, why don't they just remove the camera to the interior of the shuttle and repair it there instead of fumbling with it in an EVA? A: The instruments are too big to take inside. The environment of the inside of the shuttle is also too dirty to do work on the sensitive instruments. We would need to build a clean room to do the work. In space we have a great near-vacuum environment that works as a clean room. Q: Several experts in space medicine have identified a "space euphoria" effect that causes feelings of intense religiosity and cosmic unity in astronauts. Have either of you had an experience of space euphoria, and if so, could you describe your experience? A: I did have a feeling looking back at the Earth and realizing how thin the atmosphere appeared of how fragile and delicate our planet really is. Also looking out at the vastness of space from orbit makes me think about how huge our universe is, beyond human understanding. Q: How do you deal with nausea if it reaches the point of vomiting? A: We all carry emesis bags on us so we can use them in a moment's notice if we need to. The important thing, however, is to try and prevent feeling nauseous by going slow and keeping your orientation upright for the first day or two. Most individuals who feel nauseous return to normal fairly quickly and are able to move around quickly and utilize any orientation. Q: Good morning, My name is Daniel, and I´m an aeronautical engineering student in Madrid. I will finish my studies this year. I would like to know what is the system of Hubble's propulsion? What is it running? Could you provide me any scheme of this system, please? Thank you very much. Have a nice day. Best regards, A: Hi Daniel, it is great to hear that you are studying in Madrid, Spain. I have had the pleasure to visit Spain on numerous occasions to be at our Trans Atlantic abort site in Moron, near Seville, Spain. Interestingly enough, Hubble has no propulsion system except the Orbiter to reboost it. It is up at a higher altitude (300 nautical miles+) than the International Space Station (200 nm) and consequently drifts down more slowly than the ISS. Without any assist, Hubble will stay in orbit until after the year 2020. On the STS-125 mission we are currently planning to reboost Hubble. To point at stars, Hubble changes it's orientation by rotating its reaction wheels and then slowing them. Hubble can change it's orientation 90 degrees in 14 minutes.
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