The United States is moving ahead on the implementation of its Vision for Space Exploration. Central to that implementation is the plan to establish an outpost on the Moon, enabled by the development of a lunar transportation architecture. NASA has made it clear that they intend to carry out the development of this transportation architecture as a national program, and consequently are not likely to be looking for any international partnering in its implementation.

However, if there is one fundamental lesson that we have learned from the international space station (ISS) program, it is that the sustainment of a long-term human presence off Earth cannot be guaranteed using a single space transportation system. In the aftermath of the Columbia tragedy, the ISS partnership would have been forced to bring the crew home and mothball the station, but for the involvement of the Russians and the availability of their Soyuz and Progress systems. In fact, merely bringing the crew home would have been a significant problem had no Soyuz lifeboat capability existed within the program.

The support of an outpost on the Moon will require a very robust transportation capability. One of the most obvious methods of meeting this requirement would be the independent development of a second transportation architecture. However, given the budget constraints facing NASA for the foreseeable future, consideration of the parallel U.S. national development of two independent systems is obviously not realistic.

There are, however, a number of other nations and space agencies that are currently in discussion with the United States on partnering in lunar exploration. Among them are some — Russia, China, Europe, India and Japan — who possess or are developing appropriate systems and technologies that could be brought to bear, within a suitable co-operative structure, on the creation of alternate lunar transportation architectures. There are also a number of private-sector initiatives, primarily in the United States, that could offer a similar potential.

The availability of multiple systems, developed independently but in a manner that ensures their interoperability, both in regards each other and to the other elements of the overall lunar exploration architecture, would significantly enhance the viability of implementation and operation of an international manned lunar outpost.

As the various space agencies currently engaged in developing an International Framework for a Global Exploration Strategy and related Global Reference Architecture, work together, they should remain mindful of the necessity of implementing such a redundant capability in human lunar transportation, supported by the establishment of the necessary interoperability standards.

Ian Pryke is a senior fellow at the Center for Aerospace Policy Research, School of Public Policy, George Mason University.