Though the Sierra Nevada Corporation (SNC) Dream Chaser spaceplane was kicked out of the running to ferry crew to the International Space Station (ISS), a variation on the craft may still end up visiting the station. As part of its bid to win NASA’s Commercial Resupply Services 2 (CRS2) contract, SNC has unveiled an unmanned autonomous version of Dream Chaser to carry cargo into orbit.
The original Dream Chaser was the standout entry for NASA's Commercial Crew Program to provide reusable spacecraft for cargo and passenger service to the ISS. Where the competitors looked like throwbacks to the 1960s with their capsule designs, Dream Chaser was a winged lifting body that was designed to carry seven passengers and crew and lands like a glider on a conventional runway after a low-g re-entry.
As it turned out, the Dream Chaser lost out to SpaceX's Dragon and Boeing's CST-100 spacecraft. SNC challenged the decision, but the U.S. Government Accountability Office denied the protest.
Now an unmanned version is being put forward for the CRS2 contract to select the next round of spacecraft to provide cargo spacecraft for the ISS.
According to SNC, the unmanned variant of Dream Chaser is similar to the manned version in its basic configuration. Both are lifting bodies that are powered by a hybrid rocket engine burning hydroxyl-terminated polybutadiene (HTPB) and nitrous oxide, and both can be launched from atop an Atlas V rocket. The main differences, aside from lacking of the life support and control systems needed for the manned variant, are that the unmanned Dreamchaser has pressurized and unpressurized cargo areas, and the wings are foldable, so it can be fitted inside a the fairing used for Ariane V rocket launches.
Source: SNC
