Discovery is home.” With those words from Mission Control, Americans and NASA officials breathed a sigh of relief Tuesday morning. The safe landing of the space shuttle Discovery in California marked America’s successful return to space after the 2003 Columbia disaster that killed seven astronauts. While the return of Discovery is to be celebrated, many questions need to be answered about the future of the U.S. space program.

The National Aeronautics and Space Administration, chronically underfunded by Congress, is an agency adrift. The president’s push for a new program to send humans to the moon and on to Mars only further confuses the picture.

Congress must decide what NASA’s chief mission is. Is it to send humans into space? Why and can some of the work be done better, or at least more safely and economically, by unmanned vehicles? The Mars rovers have catapulted forward scientific knowledge of that planet and our universe in ways that no manned mission has.

If we want humans in space, where do we want them to go? To other planets or to continue work on the International Space Station? It appears that the current answer is both. Is it feasible to work on two very different missions at once, especially when the space station relies on re-supply and repair missions by the U.S. space shuttles? The shuttles are now grounded while NASA continues to try to rectify the falling foam problems that doomed Columbia and required a homemade hack saw to fix on Discovery as it orbited more than 200 miles above the Earth.

NASA has long planned to retire the aged space shuttles, which have made 114 journeys to space, by 2010, yet the agency doesn’t plan to have a replacement vehicle until 2014. According to press reports, the new technology will involve two separate vehicles to carry cargo and astronauts. It will be safer and able to carry six times as much cargo as the shuttle.

According to a 2004 NASA document, the goal of the agency, as laid out by the president, is to “advance U.S. scientific, security, and economic interests through a robust space exploration program.” To do this, NASA is supposed to explore the solar system with humans and robotic equipment while developing innovative technology and knowledge. Ultimately, the goal is to “extend the human presence across

the solar system.”

What the document doesn’t answer, except to reference man’s long history of voyages of discovery, is why.

The days of bravado that prompted President Kennedy to successfully send a man to the moon are over. It is not enough to say Americans will be the first to land on Mars. There must be good reason to invest taxpayer dollars, and possibly human lives, in such a mission.