NASA Commercial Spaceflight — 60 Day Report
The space shuttle was the world’s first reusable spacecraft, but it will not be the last. All three of NASA’s CCiCap partners are designing their commercial crew transportation vehicles to be reused after ferrying NASA astronauts and other customers to and from low Earth orbit.
According to Jim Voss, vice president for Space Exploration Systems and the Dream Chaser Program Manager at SNC, “The space shuttle is the only spacecraft ever to return to space because it had wings that allowed it to land softly on a runway. Our Dream Chaser human spacecraft is similar in design so it can fly many times to orbit. This will make the flights cost effective since most of the vehicle is reusable and requires minimal maintenance between flights. When you don’t need to build a new spacecraft for each flight, there is a much better business case for commercial transportation services to Earth orbit.”
The maintenance turnaround effort will be much quicker than the space shuttle. Dream Chaser’s thermal protection system tiles cover only 1/17th the surface area of the shuttle, so it will require less maintenance time. Also, there are no hazardous propellants or commodities on board that require special precautions for processing. The Dream Chaser’s hybrid rocket motors and one set of batteries are easily replaced, and the remainder of the vehicle is planned to be reused for multiple flights.
Both Boeing’s CST-100 and SpaceX’s Dragon are capsules, which descend through the atmosphere on parachutes like the Apollo capsule. Unlike Apollo capsules, which were not reused after their missions, the CST-100 and crewed Dragon will land on land, facilitating reuse of the crew descent portions of the spacecraft. The Dragon will cushion the landing impact with rocket motors that double as abort engines. This will avoid the high impact loads and damaging affects of splashdowns in the ocean. Furthermore, Dragon’s “PICA-X” heat shield, which already has been flight demonstrated on multiple orbital test flights, has been designed to be reusable.
Boeing also plans to cushion the impact of its vehicle’s land landings beyond that achievable by parachutes alone. The CST-100 includes an airbag system that absorbs landing shock such that the spacecraft structure and systems can safely be reused. These airbags already have been demonstrated through multiple tests during CCDev2.
“Refurbishment and reuse of our crew modules – nominally for up to 10 missions – enables us to offer more affordable pricing for services, which is important for helping to ensure the growth of the commercial market that we envision.” said John Mulholland, Commercial Programs vice president and program manager for Boeing.
Affordability of low Earth orbit crew transportation is one of the primary goals of the NASA’s Commercial Crew Program and its industry partners, opening up the space frontier to a new and larger market of passengers. By designing major portions of the transportation system to be reusable, and avoiding the high recurring costs of manufacturing, assembly, and test of the most complex and expensive elements, the costs per seat will be reduced significantly.