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Ask the Experts

Ask the Experts

John M. Grunsfeld

Dr. John Grunsfeld is a veteran of five spaceflights, including three to the Hubble Space Telescope, in 1999 and 2002 and the most recent in the spring of 2009. Selected by NASA in 1992, he has since logged over 57 days in space. 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.

Michael J. Massimino

Dr. Michael Massimino has more degrees than you can shake a joystick at. He has a B.S. in industrial engineering from Columbia and three degrees from M.I.T.: a master's in technology and policy, and a master's and a doctorate in mechanical engineering, respectively. With such credentials, it's no surprise that NASA chose him to be an astronaut in 1996. Prior to his first spaceflight assignment, Massimino served in the Astronaut Office Robotics and Astronaut Office Extravehicular Activity branches. In March 2002, Massimino flew on a Hubble-repair mission with John Grunsfeld, above. The most recent Hubble servicing mission in the spring of 2009 has upped his total days in space to 22. Married with two children, he lives in Franklin Square, New York and serves as an adjunct professor at both Rice University and Georgia Tech.

On August 28, 2009, astronauts John Grunsfeld and Mike Massimino answered selected viewer questions about the successful mission they and their team conducted in May 2009 to repair and upgrade the Hubble Space Telescope. Please note we are no longer accepting questions, but see Follow the Hubble Repair and Links & Books for more information.

Q: Hello Dr. Grunsfeld and Dr. Massimino,

It was incredible to watch you perform your Hubble Mission via the Internet. My question is: How does it feel to train so hard and then ultimately succeed on such a high-profile mission? When you returned to Earth, is there any longing to be back up in space, or is it the opposite—were you just happy to be back on solid ground?

Eric Haynes, South Korea

A: John: I wish I was in space now. I love being in space, but I am also glad to be back with family and friends. The best would be to fly in space with family and friends.

Mike: I miss being in space but am very grateful to be back on Earth with my family and friends. I am also grateful that our mission was successful and that we left Hubble in better shape than when we arrived.

Q: I believe you had problems removing a bolt. Did anyone make the suggestion to tighten it slightly then try again to loosen it? I have found this useful in removing bolts seized in boats.
Pete Frey, Danbury, Connecticut

A: John: That might have helped on some of the bolts. Fortunately, we were able to get them out without trying that. The torque at which the bolt breaks doesn't really care which way we turn, and we didn't want to break them.

Mike: Nice idea: You should apply for a job in the Mission Control Center.

Q: Hello! Did you at any point feel like the mission wouldn't succeed? What would be the bare minimum you could have done and have the mission be considered a success? Or was it all or nothing? Thanks.
Laura S., Charleston, South Carolina

A: John: We had a list of minimum success: WFC-3, Gyros, SIC&DH and Batteries, but we really wanted to get it all done. The only doubt I ever had was right off the bat with the stuck bolt and WFC-3, and then the stripped screw on the STIS repair. But even then I thought we'd find a way to get them done.

Mike: I was pretty concerned during spacewalk number 4 during the Space Telescope Imaging Spectrograph (STIS) repair when I was not able to remove the handrail with our power tool as planned. Once I heard the solution of ripping of the handle, I was confident that we would be successful. But it was a little dramatic for a while.

Q: Has there been any degradation in signal or data transfer noticed due to the accidental damage to the antenna on clean up and close out?
Robert, Fall River, Massachusetts

A: John: No, the cover was designed to pass the signal. A benefit of the cover is that the thermal conditions are now better for the antenna and it will last longer.

Mike: Although the damage was an accident, it appears to have worked out for the better in the end.

Q: Why in the world did they cancel the re-boost? I see from other blogs that NASA PAO [Public Affairs Office] said it wasn't needed but also that there was no risk associated with it. Given you had one chance to do it and if in 2020 you changed your mind and wanted to keep it going or something, wouldn't it have made more sense to do it anyway?

A: John: Given the mildness of the solar cycle and the forecast that the telescope will stay up until the early 2020s, and the fact that our propellant was more limited due to the staged de-orbit we did (to minimize the orbital debris risk), it was decided we didn't have excess propellant to do the boost.

Q: Has anyone ever become ill on a mission? What do you do?
Fidel Hernandez, New Jersey

A: John: Sometimes astronauts feel a little ill or get minor scrapes. I trained as a crew medical officer to do basic treatment. Fortunately, no one has been so ill that we've had to come home.

Mike: Some astronauts don't feel great the first day in space as the body adapts to weightlessness. But by the second day just about everyone feels fine. We are put in a health stabilization quarantine one week prior to the launch to lower the possibilities of getting sick.

Q: Does an astronaut feel tired after a spacewalk just as a person would feel after a workout on Earth?
Anil, Hudson, Ohio

A: John: After my spacewalks I am quite exhilarated, but also tired similar to a workout on Planet Earth.

Mike: A spacewalk is a lot of hard work and continuous physical workout that in our case lasted up to eight hours. So yes, we can get tired from spacewalking. However, it is such a big day in your life that you are extremely motivated to get the job done and also to try to conserve as much energy as possible so that you can get through the spacewalk successfully. We had two teams of spacewalkers so that nobody needed to spacewalk two days in a row.

Q: Why was the team surprised at the torque needed to remove the screws? Could the conditions not been duplicated on Earth's surface?

A: John: We had predictions of the torque need to remove the screws and bolts. The instruments were installed with a specified torque. We expected the removal to be about the same. The "interesting" part is that the bolt actual release torque was close to the failure torque for the bolts.

Mike: Hubble always seems to provide plenty of challenges when being serviced, and dealing with the extra torque was a challenge. However, our team did anticipate many of the potential problems—including the possibility of needing extra torque)—and we were able to overcome the challenges we faced by working together.

Q: Do those data images from Kepler pass by Hubble first before they get to Earth?
Jackenson Durand, Malden, Massachusetts

A: John: Kepler and Hubble are in very different orbits. Each spacecraft gets light from a different path direct from the sources.

Q: Whatever happened to that stuck bolt that Drew finally dislodged by force?
Gus Pehur, Farmington Hills, Michigan

A: John: The bolt is attached to the WFPC-2, which we brought back to Earth. WFPC-2 and the "bolt" should be on display at the National Air and Space Museum in Washington, D.C. soon.

Q: You both have been to space so many times! Do you ever contemplate any other job? Will you put a limit on your space travel, or do you plan on continuing as long as NASA lets you?
Donna, London, England

A: John: I would love to be an astronaut forever, but I also love science and building spacecraft, so while I'd love to go to space again, I've achieved a rare dream already.

Mike: The astronaut job is a boyhood dream for me and the best job in the world in my opinion. So it is all downhill from here.

Q: Can you compare spacewalking to any other experience you've had in your life—in terms of the excitement, the sense of danger, the importance of what's at stake?
Pete Flannigan

A: John: I can't think of another activity I've done that contains all of what you ask. Mountain climbing comes closest, but not the real importance to society or the world.

Mike: Closest thing for me is scuba diving, where you are interacting with a different environment and get to see some beautiful things while depending on equipment to keep you safe.

Q: Given the long odds of making it, would you encourage a child or young person to want to be an astronaut? Where do you think such aspirations can lead?

A: John: I never thought much about the odds until I was a young adult. In the meantime it was a great dream that stimulated me to study my main love of science.

Mike: When I started applying to be an astronaut I thought it was the best job in the world but also that it was one of the toughest jobs to get and that it was unlikely that I would be selected. However, you never know unless you try. I think it is better to pursue your dream and not reach it than to not try at all. At least you don't have to ask yourself "what if?" when you grow old. And always remember: Sometimes dreams come true.

Q: I am a scuba diver and was wondering: Does the weightlessness of space actually compare to the feeling you have in the pool where you practice your spacewalks? Or is it totally different?
Sophia W., Cleveland, Ohio

A: John: It is both different and the same. I often feel while scuba diving that I'm floating in space with the freedom of movement. Yet the total feeling of continuous weightlessness is so magical that it is still very different.

Mike: The pool gets us prepared to do the actual work on the telescope, but gravity still has an effect on us and on our tools in the pool. Nothing can prepare you for the view on-orbit.

Q: Are you scared on spacewalks? Do you meditate before launching? How do you stay calm? Thank you.

A: John: I was not really scared on my spacewalks. We practice so much and need to stay so focused that it has a calming effect on me. I do a kind of visualization and meditation in the airlock prior to going outside, to guide my first activities once I get out in space.

Mike: I was not scared but rather pretty excited and grateful to get such a great opportunity. I was concerned about the work and focused on that as well as trying to enjoy the experience.

Q: What are your thoughts on the recent hullabaloo over space tourism? Do you think that cruising around the galaxy is something that should be left to the professionals?
Darcy F., Boston, Massachusetts

A: John: Space travel is so absolutely unique and wonderful that I hope as many people as possible are able to go in the near future. Not a five-minute parabolic jaunt, but to orbit the beautiful blue Earth and beyond. If space tourism can really take off, it will provide that opportunity eventually.

Mike: I have seen some beautiful sights on-orbit and would hope that space tourism grows so that as many people as possible can experience spaceflight.

Q: When you were growing up, did you want to be an astronaut? Or was that something that came with the love of science, physics, engineering, etc.?
Melissa Hall, Boston, Massachusetts

A: John: I wanted to be a scientist in space, and to do that I had to become an astronaut. Both interests started about the same time, when I was about seven years old.

Mike: I wanted to be an astronaut when I was six years old. As I went through high school it sort of moved to the back of my mind and resurfaced after I completed college.

Q: Here's a personal question for the astronauts onboard the Hubble repair mission: What was it like when you looked out a shuttle window for the first time and saw Earth?

Also, can you talk about your thought process in disregarding the risks of space travel to repair a piece of machinery? Why does it mean so much to you that you would risk your life?

A: First question:

John: The Earth is an incredible planet and I never tire of looking out the window. My first look was a real WOW moment.

Mike: The view of the Earth is too beautiful for words. I felt as though I was looking at absolute paradise.

Second question:

John: For me fixing the machinery is more about enabling truly great science. For the science and knowledge, the risk is worth it.

Mike: I think pursuing a dream is worth some risk.

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