• OPINIONS
• PAST SUCCESSES

browse projects: Apophis Mission Design Competition Asteroid Impact Mapping System Catalog of Exoplanets Drive a Mars Rover Extrasolar Planets Transit Search International Lunar Decade LIFE Experiment: Phobos Mars Climate Sounder Team Website Messages from Earth Observing Earth Pioneer Anomaly Planetary Microphones S.O.S: Save Our Science! SETI Optical Telescope SETI Radio Searches SETI@home Shoemaker NEO Grants Solar Sailing Space Advocacy Space Information Stardust@home Target Earth Visions of Mars

browse space topics: 2001 Mars Odyssey Asteroids and Comets Cassini-Huygens Chandra X-Ray Observatory Chandrayaan-1 Chang'e 1 Compare the Planets Dawn Deep Impact Earth Extrasolar Planets Genesis Hayabusa (MUSES-C) Hubble Space Telescope Jupiter Kaguya (SELENE) Lunar Reconnaissance Orbiter (LRO) Mars Mars Exploration Rovers Mars Express Mars Global Surveyor Mars Reconnaissance Orbiter Mars Science Laboratory Mercury MESSENGER Moon Near Earth Objects Neptune New Horizons New Horizons Digital Time Capsule Past Missions Phoenix Planetary Analogs Planetary Exploration Timelines Planetfest 2008 Pluto and Charon Pluto Top Ten Postcards from Venus Private Missions Rosetta Saturn Search for Extraterrestrial Intelligence SMART-1 SOHO Space Imaging Spitzer Space Telescope Stardust Trans-Neptunian Objects Ulysses Uranus Venus Venus Express Voyager Weekly Planetary Radio Trivia Contest

Should the Space Shuttle Fly Again?

A Statement by The Planetary Society,

October 11, 2005

Space Shuttle Discovery Credit: NASA/KSC

The space shuttle era is over. NASA has committed to retire the shuttle by 2010 as a key part of the Vision for Space Exploration, the new (2004) U.S. policy for human and robotic space exploration. The plan was made in the expectation that the three remaining orbiters could carry out the flights needed to complete the International Space Station (ISS) and that a new Crew Exploration Vehicle (CEV) could operate by 2014. NASA Administrator Mike Griffin now hopes to advance that date several years, but budget constraints may limit his ability to do so.

Recent events have made the road rougher for implementing the Vision. The return to flight after the Columbia accident has not gone well, with another seven- month delay after the July 2005 Discovery mission. After the impact from Hurricane Katrina is assessed, this delay will almost certainly become longer.

The cost estimates for returning the shuttle to regular flights are also soaring – an internal NASA memorandum has suggested that more than one billion dollars extra per year will be needed to meet the shuttle’s demands. With growing budget deficits, the wars in Iraq and Afghanistan, and massive post-Katrina expenses, it is hard to see how that could happen. NASA may have to choose among continuing to fly the shuttle, getting started on space exploration, or cutting other elements of its program.

The primary reason to continue flying the shuttle is to complete the ISS. (Servicing the Hubble Space Telescope is important, but if there is no shuttle for space station assembly, it certainly won’t be available just for the Hubble). Completing the ISS is less important to the United States than it is to Europe, Japan, and Canada. They joined the ISS program to gain human space flight experience and because they felt it prudent to respond positively to the U.S. invitation to participate. Honoring these international commitments should be important to the United States since it will likely need the cooperation of other spacefaring countries to advance the even more ambitious goals in the Vision for Space Exploration.

The Planetary Society has long supported “a space station worth the cost,” that is, one that will advance human exploration of other worlds. We also strongly support international cooperation in great space ventures and do not take lightly the European and Japanese interests in the space station, nor those of other countries, specifically Russia and Canada. Even if the ISS could not be made useful for the Vision for Space Exploration (and we think it can), we would support the completion of ISS for use by all its partners.

But does completing the ISS require the shuttle? The quick answer is yes. No other alternatives have been identified – but then again no other alternatives have been seriously studied. Clearly no one would want to fly the shuttle if it were totally unsafe or prohibitively expensive. Now it is “only” partially unsafe, and is certainly very expensive. Prudence and experience strongly suggest we plan for the possibility that the shuttle remains unavailable. The Planetary Society urges all ISS partners to consider a “plan B,” looking at alternatives to the shuttle for completing an ISS worth having.

Let’s consider alternatives:

• Don’t finish the ISS. We do believe that ISS can be used to advance and support the Vision for Space Exploration by preparing astronauts for long-duration flight into the solar system. More important, the international partnership started on ISS is necessary for public, political and financial support for great ventures in human space flight – to the Moon, Mars, or anywhere else. There is little support or even a strong rationale for a purely nationalistic approach, and opportunities for humankind are so much greater if it is a venture of Earth, rather than of only America (or China, or Russia, or Europe, or Japan, etc.).

• Engage the international partners to seek a solution, instead of treating the current international partnership on the ISS as a problem. Let the United States convene the partners, admit that there is a space shuttle problem, and ask their help in working out alternatives. Such honesty would be a sign of strength and leadership.

• Investigate other launch vehicles for cargo flights. The international modules (already built by Europe and Japan) were specifically designed to fit only in the shuttle bay. ISS partners operate a wide range of launch vehicles. Their use, with some modifications to deliver cargo to the space station, might be expensive but not impossible. And some options might be less expensive than using the shuttle (especially when figuring in the risk of human flight – even under the best of circumstances.)

• Use the shuttle-derived heavy lift launch vehicle even if it requires a delay of a few years in completing the ISS. The big European and Japanese modules could be delivered by the new vehicle that NASA already plans to develop for future human exploration beyond Earth orbit. Such a vehicle is not planned to be available until well after 2010, so, it is not a near-term solution. But it is not clear that the shuttle approach is near-term either.

• Use the Soyuz for crew flights until the CEV is ready. ISS crews can continue to be delivered by Soyuz, launched either from Russia or possibly in the future from the European launch site in Kourou. Some have objected to this approach because they feel it is dangerous for the U.S. to lose control of its only means to send humans to space. Dangerous to what interests? There are no national security objectives for human space flight, and the United States has just endured a two-year hiatus without endangering the country. (It is the third such U.S. hiatus – there was a six-year hiatus after the end of the Apollo program and a nearly three-year hiatus after the Challenger accident.)

It is possible that the result of a consideration of such alternatives will be a conclusion that the shuttle is the best way to proceed. Then at least we will be prepared with a back-up plan if something further happens to the shuttle. Or maybe a better international plan and partnership might result in a post-shuttle plan that could more fully serve the course of human exploration of the cosmos, not just for the benefit of NASA, but for all humankind.