BarbaraHudson writes Due to a challenge by Sierra Nevada, NASA has asked the winners for the next earth-to-orbit launch vehicles to halt work, at least temporarily. "After rewarding Boeing and SpaceX with the contracts to build the spacecrafts NASA is now asking the companies to stop their work on the project. The move comes after aerospace company Sierra Nevada filed a protest of the decision after losing out on the bid. Sierra Nevada was competing against Boeing and SpaceX for a share of the $6.8 billion CCP contracts. The contracts will cover all phases of development as well as testing and operational flights. Each contract will cover a minimum of two flights and a maximum of four, with each agency required to have one test flight with a NASA representative on board.... According to NASA's Public Affairs Office, this legal protest stops all work currently being done under these contracts. However, officials have not commented on whether-or-not the companies can continue working if they are using private funds."