There are powerful arguments for the United States to continue the space shuttle until a suitable replacement vehicle is available and proven.

  • In case of ISS emergency: Over the next nine-plus years, the international space station (ISS) will be continually exposed to the possibility of an accident in space that could make it uninhabitable and/or with a loss of control. If any of this happens, or even one critical module fails, the shuttle could be the only way to either make it functional again or provide for controlled, safe re-entry. An uncontrolled re-entry of the ISS could expose large numbers of people around the world to large falling pieces with potentially tragic consequences. This risk is unacceptable.

The recent failure of the Russian Progress vehicle has sounded a wake-up call to remind us that spaceflight is a risky business. Since the Soyuz crew vehicle shares its launcher with the Progress vehicle, Soyuz will also be affected. If the ensuing failure investigation and recovery take an extended time before both Russia and the United States believe the Soyuz is safe for crew launches, ISS operation could be significantly compromised. Unfortunately, a shuttle is not ready to step in to help; however, in case of a future Russian problem, from equipment failure to political issues, the shuttle could be invaluable.

Commercial crew launchers will face an extended period of test flights to discover unknown flaws, present in any new launch system. There is a significant risk that a failure could occur during this period of “infant mortality.” In such cases, the shuttle would also be an extremely valuable asset. For the next five to seven years, we should use the shuttle as the primary transportation mode to the ISS, leaving the Russians to service the Soyuz lifeboat.

  • The shame of buying rides from Russia: Both the current and the previous presidential administrations would have U.S. astronauts buying rides from the (potentially unreliable) Russians for at least five to seven years. The U.S. space program would then become second or third globally in the eyes of millions in the U.S. and around the world. The shuttle could keep U.S. astronauts flying on proven U.S. launchers and avoid this ignominy.

Many experienced and respected space experts, including Neil Armstrong, Chris Kraft and John Glenn, have emphasized the importance of assuring that America remains first in the world in space. A majority of Americans agree with them. A slump of a half-dozen years with no U.S. astronauts launching on U.S. launchers would be unacceptable.

The Augustine committee, tasked in 2009 with reassessing the future of NASA’s human spaceflight program, did not recommend retirement of the shuttle. John Holdren, adviser to President Barack Obama for science and technology, directed the committee to assume that the shuttle would be retired.

The Obama administration has maintained that the reason for retiring the shuttle is the lack of funds to both fly the shuttle and develop a new human exploration vehicle. However, this was partially refuted when NASA received a credible proposal for fixed-price commercial operation of two of the existing three shuttle spacecraft. The third would be used for spare parts. Reusable Space Shuttle Main Engines already in inventory would suffice. The shuttle budget would then be reduced by about half, amounting to less than one-tenth of the total NASA budget. Shuttle operation could continue until the U.S. has a reliable and safe replacement.

  • An affordable alternative to the unsustainable Space Launch System (SLS): The SLS, the heavy-lift rocket Congress ordered NASA to make ready for flight by 2016, would be a very good system to have, but NASA cannot afford it now. Proceeding with SLS contracts would commit NASA to building or modifying large facilities with very high fixed costs for decades. The SLS would use current fuels and technologies but be very expensive to develop and maintain.

Missions for the proposed giant SLS have not been defined. As a result, critical functional design requirements remain a guessing game.

The Augustine committee’s foremost recommendation was that NASA should avoid starting any large development project without assurance of enough future funds to complete the project. Accordingly, the SLS is likely to suffer the same fate as the canceled Ares 5 of the Constellation program, and for the same reason.

In any case, such a huge launcher would not be needed for at least 20 years, when NASA starts to assemble human missions for a lunar base or to Mars.

Until the 2030s, any one of several of today’s existing launchers, or even one of the upcoming commercial crew launchers, such as the Atlas 5 or Falcon 9, could be used to assemble spacecraft in low Earth orbit (LEO) for human exploration missions to geosynchronous Earth orbit, to orbit the Moon or to visit an asteroid. Early human missions to these destinations, leading and supporting more aggressive later missions to the surface of the Moon or to the vicinity of Mars, would provide an early and periodic boost to human space exploration.

Orbital assembly in LEO is a proven technique, having been used in construction of the 460-ton ISS with the shuttle. The use of existing storable propellant engines for propulsion beyond LEO, in conjunction with existing and proven cryogenic fueled stages, could facilitate timing of assembly in LEO without waiting for development of an operational fuel depot for cryogenic fuels.

Very important robotic missions for planetary exploration and precursors to human exploration have been cut in favor of the SLS in the administration’s proposed fiscal 2012 budget for NASA. The science community and Planetary Society are very concerned.

In these difficult economic times, and especially over the next several years, this nation needs a continuing stream of positive news and an optimistic “can do” outlook more than ever. NASA is one of the few federal government programs about which most people would say, “My federal government does that, and I am proud of it.” NASA’s budget, at only one-half of 1 percent of the federal budget, is a very low price to pay for such a valuable asset for the United States.

If we continue with the SLS, the outlook is grim. It appears unlikely that NASA will receive the budget increases in future years necessary to continue development of the SLS. Several years’ delay and many billions of dollars would be largely wasted as they were with the Constellation program.

Within expected budget totals, if we place our priorities properly, we can safely continue to operate the ISS, move forward with a practical and sustainable human exploration program, and keep America first in space through 2020.

Even though politically difficult, our leadership must commit, even at this late date, to continue the shuttle and end the SLS. Any alternative will cede space leadership to other nations, doom the U.S. human space exploration program to nothing except good-sounding but go-nowhere, wasteful technology demonstrations, and keep NASA “marching in place” for years to come.

We should rethink the decision to retire the space shuttle. In today’s economic situation, it would be a tremendous bargain for the nation. It is not too late to do the right thing for the nation and for the future of U.S. human space exploration.


O. Glenn Smith is a former manager of systems engineering for the space shuttle at NASA’s Johnson Space Center.