FIGURE 5.1 The Orion spacecraft. The overall configuration is similar to that of the Apollo spacecraft. NOTE: GRC, Glenn Research Center; JSC, Johnson Space Center; LaRC, Langley Research Center. SOURCE: Courtesy of NASA.

low lunar orbit for up to 180 days. At the end of the lunar phase of the mission, the Altair would launch from the surface and rendezvous with Orion for the return to Earth. The command module would perform direct or skip reentry and make a precision water landing off the coast of California.

The core capabilities for the ISS mission are launch by way of Ares I for a crew of up to six, automated rendezvous and docking with relative navigation sensors, and a low impact docking system (LIDS). Orion then remains at ISS for up to 180 days and undocks for return to Earth.

Additional capabilities are available with further small- or large-scale design work. These include the delivery of unpressurized cargo to the ISS with volume of up to 2.92 m³ and mass up to 600 kg, the ability to configure the service module as a stand-alone element (ability to deliver a payload to a particular location), and the capability of being used in a modular fashion.

Although the Orion spacecraft is still in a relatively early stage of development, NASA has reserved payload space and mass at the rear of the vehicle for potential science payloads (see Figure 5.2). These could include both attached payloads and small deployable satellites. The committee did not receive any such small-payload proposals in response to its request for information (all of the mission proposals that the committee evaluated are large, multiton experiments), but this payload capability offers the potential for interesting and worthwhile science to be conducted on Orion flights. This would enhance Orion’s capabilities.

As of the writing of this report, opportunities appear to exist to attach experiments to the service module on lunar missions. Studies and analyses to evaluate various options are in progress. The Orion designers currently