MarkWhittington writes: NASA Administrator Charles Bolden has been making the rounds of congressional committees, defending the indefensible, that being the latest Obama space agency budget proposal. Thursday it was the turn of the House Science Committee to complain to Bolden that the budget underfunded the Journey to Mars and to vow that more money would be forthcoming. One of the other complaints Congress has been making is that NASA lacks a plan to get people to Mars, scheduled to happen sometime in the 2030s. Bolden was coy, suggesting that the time was not right to start firming up architectures and missions. However, he did drop an intriguing hint that a nuclear thermal rocket engine being developed at NASA's Marshall Spaceflight Center may take people to Mars quicker than chemical rockets.