Future Mars Rover mission Earthbound a little while longer

NASA's next-gen Mars Rover mission has suffered yet another setback:

Development problems and increasing costs are threatening to delay the landing of a nuclear-powered rover on Mars next year.

NASA Administrator Michael Griffin told the U.S. House Science and Technology Committee this month that the space agency's engineers had to redesign a risky heat shield on the Mars Science Laboratory. Tests have shown that the shield could not survive entry to the Martian atmosphere, and designing a new one meant pushing back the mission.