Monday, July 17, at 11 a.m. ET
Space Shuttle Discovery Lands
Monday, July 17, 2006; 11:00 AM
Valerie Neal, Post-Apollo Human Spaceflight for the Smithsonian National Air and Space Museum, will be online Monday, July 17, at 11 a.m. ET to discuss the return of the space shuttle Discovery from its thirteen-day mission this morning.
Monroe, Mich.: Is the Space Shuttle program really worth the cost and does it have a purpose anymore? Bush stated that we should next venture to Mars, yet we continue to waste time going to the International Space Station doing experiments that barely relate to a Mars missison. Is the next generation space launch vehicle even under design?
Valerie Neal: You have hit the heart of the controversy that has followed the space shuttle and space station since their beginnings. Value or worth is in the eye of the beholder and his/her vision of the long-term goals of space exploration. Part of the purpose of both the shuttle and ISS is to gain experience in long duration spaceflight and human adaption to space, to permit the longer voyages to Mars. Yes, the next launch vehicle is under design; it was just recently names Ares (for Mars). Let's see how it progresses.
Conroe, Tex.: Hi Valerie: I'm a life-long follower of human space flight, and I have a concern about the scheduling of upcoming STS flights.
I believe that pushing the remaining 16 or 17 STS flights into orbit by the end of 2010 is not realistic. I feel that fulfilling the U.S. obligation to complete construction of the International Space Station will take longer than four years.
Am I right?
Valerie Neal: You may be right; we will have to see how things play out. It will be a brisk pace and it doesn't leave much margin for problems or surprises. However, if upcoming missions are as successful as this one, it should be possible to finish the ISS to the agreed-upon level by 2010, or maybe 2011 if necessary.
Washington, D.C.: From watching this morning's landing, it appeared that there was some concern about storms that appeared on the radar after NASA had directed the shuttle to begin its descent. Obviously there cannot be an abort back into orbit once that happens, so my question is what would have happened had it started raining at the Kennedy Space Center. Would they have diverted to some other nearby facility, or would they have just risked a landing on a wet runway? (I cannot imagine a shuttle landing at Orlando-MCO!)
Valerie Neal: Good question; I'm pretty sure there is no Plan B at that point ... once descent begins, the Shuttle goes to the primary landing site. Remember, it has no maneuvering power to change its flight path. The big concerns about storms are lighning and high winds, but once the vehicle has started down, it can't avoid the weather. NASA is always conservative about giving the go for launch and landing.
Quebec City, Canada: Hi,
I was watching the landing on NASA TV. About five to ten minutes before the touchdown, I heard these popping sounds that seemed like gunshots. I'm sure it was normal, but what was that? (Somebody shooting birds at the airport :)
Valerie Neal: I didn't hear those sounds, but I heard some like that after touchdown. My guess is that some microphones were picking up some kinds of sounds on the ground. Write back if you figure out what they were.
Ann Arbor, Mich.: Each Space Shuttle mission seems to have at least one woman and one Black person as crewmembers. Is this a conscious effort by NASA to have a diverse crew or is it simply a coincidence? Whatever the reason, I commend NASA for the diversity of the Shuttle program.
Valerie Neal: In the early days it was a conscious effort to integrate women and racial/ethnic representatives into the missions (STS-7 with Sally Ride, STS-8 with Guy Bluford, for example). Now it's really a natural reflection of a more diverse astronaut corps. Crew assignments are made on the basis of competencies and experience. This crew happened to include an African American woman; the next one has a woman but not an African American. It's not a formula based on race or gender but on mission requirements and individual capabilities.
Bowie, Md.: I am amazed that we have not lost an astronaut during a spacewalk. Hasn't NASA defied the odds with not losing an astronaut in space? How do you think such a loss would affect the Shuttle program?
Valerie Neal: That's an interesting question. I'm not sure that there are many ways to lose an astronaut during a spacewalk, because there are so many precautions and redundancies. A loose or broken tether? The tethers that attach astronauts to the shuttle or the RMS workstation or the ISS worksites are basically indestructible, and it takes 3 separate actions to unlock a tether, so it can't be loosened accidentally. A faulty spacesuit? The suits are checked out thoroughly before flight and then again in the airlock before EVA. You can always get back inside quickly if you have a problem with battery power or air supply. It seems this risk has been thought through and provided for very well. With caution and good training, EVA has proved remarkably successful.
Washington, D.C.: Were those popping sounds the sonic booms as the orbiter slows below Mach 1?
Valerie Neal: The sonic booms are really "booms" -- one loud clap after another.
Baltimore, Md.: Why the crew did not come out immiedetely after touching down?
Valerie Neal: They have some work to do inside, first, shutting down the vehicle and safing it. They also change out of the launch-entry suits and get a quick look-over by a flight surgeon. They usually exit in about 45 minutes to an hour and head back to the crew quarters to say hello to their families, get a more thorough medical check, and take a shower before they appear in public at the press conference.
Washington, D.C.: How important was the probe that they had trouble deploying? I suppose both would be a disaster.
Valerie Neal: Are you talking about the air data probe that balked a bit during descent? The vheicle has another that did deploy, and both provide the same information, so it wasn't a big problem. It finally did deploy a couple of minutes late. No potential for disaster there.
Alexandria, Va.: I've seen space shuttle Enterprise at the museum's Udvar-Hazy Center. What's the difference between Enterprise and the rest of the shuttle fleet? And what would I see in the cockpit of Enterprise? It's too bad visitors can't go inside.
Valerie Neal: A lot of people wish they could go inside, but unfortunately it isn't practical with the large crowds and difficult access. Enterprise is partly a flight vehicle and partly fake; it was never completed for spaceflight. It doesn't have engines or actual thermal tiles, so it can't launch or reenter. However it can (and did) fly in the atmosphere during a series of approach and landing tests in 1977. The cockpit was stripped before NASA gave Enterprise to the Museum, and the crew cabin and payload bay are largely empty shells. But it looks great from the outside! People love to see it!
Toronto, Canada: Does your museum want the space shuttles when they're retired from NASA? Where would you put them all?
Valerie Neal: Yes, the National Air and Space Museum hopes to acquire one or all of the flown Shuttles, to ensure their preservation. Of course, other museums and NASA visitor centers would like to have a Shuttle, too, so there will be some negotiation to reach decisions about where best to keep and display them. I anticipate that they will end up in several different places that can provide responsible care and access to many visitors.
Silver Spring, Md.: What's the difference between the space shuttle and SpaceShipOne, which is now hanging at the Air and Space Museum? Which one is safer?
Valerie Neal: First difference: size! The space shuttle is like a large jet aircraft; SpaceShipOne is more like a Cessna. Second difference: space shuttle is part of a big government program; SpaceShipOne is private enterprise, a small research project aimed at laying the foundation for commercial spaceflight and tourism. Another difference: SpaceShipOne is very lightweight and is carried up to launch altitude by an airplane. Then it fires a single rocket to get into space. The space shuttle has a very much more powerful propulsion system.
Bowie, Md.: Valerie I am a bit disappointed by your answer on the potential loss of an astronaut during a spacewalk. We take similar precautions during launch, but have lost two Shuttles: Challenger and Columbia.
Valerie Neal: Sorry to disappoint, but I think the launch and reentry tragedies are different circumstances. In both cases, there were known safety problems that had not been adequately addressed, and they finally took their toll. I don't know of any comparable unresolved safety issues that pertain to EVA, but educate me if I'm wrong.
Monroe, Mich.: Will the U.S.-planned mission to Mars be an international effort of will it be an entirely U.S. undertaking? Also, why have we not seen the similiar political and national support for the Mars mission as we saw for the Moon missions of the 1960s?
Valerie Neal: Most likely any mission to Mars will be an international effort because the cost and commitment will be greater than one nation can support. The question is who will lead the effort: the US? Europe? Japan? China? others with spacefaring aspirations? maybe a commercial venture rather than governmental? Re: where is the political support, most analysts agree that the Cold War competition with the Soviet Union accounted for the support for the Apollo missions. Without that geopolitical rivalry and urgency, it is hard to build support for a long, costly project.
Valerie Neal: Time's up. I'm sorry that I wasn't able to answer a few other questions, but I appreciate your joining this chat so thoughtfully. It was good to "talk" with you.
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