President Bush's 2006 budget recommends $16.5 billion in budget authority for the nation's space program and roughly half of that will be devoted directly and indirectly to manned space activities. Most of the remainder will go toward supporting the NASA scientific program, which chiefly carried out with unmanned space vehicles. NASA's unmanned space probes and satellites have helped create a "golden age of astronomy" and given humankind a vastly improved understanding of the universe and their place in it. The scientific community widely views the manned space flight program as a large waste of resources.
The core of the manned space effort over the past 25 years has been the space shuttle. The shuttle was initially conceived and sold as an inexpensive and effective way of sending human beings into space on a large number of scientific and military missions. Originally it aimed at launching between 25 and 60 missions a year. But the staggering costs of the life-systems needed for manned space flight and the consequent limitations of weight-load and space capacity sharply downgraded its usefulness for both military and scientific missions.
Compared to unmanned delivery vehicles the space shuttle is too expensive for close-to-Earth missions and cannot support human life long enough to deliver payloads to further out regions of the solar system. The number of launches was cut sharply below the original plan and from 1998 to 2002, an average of only five launches a year were undertaken.
The scientific projects that are suitable for and carried out in the space shuttle are widely considered by scientists as low priority. Historian Alex Roland put it best: "Any specific mission you can identify to do in space, you can design and build an unmanned space craft to do it more effectively, more economically, and more safely."
As a result of changes in response to the Columbia disaster, the program has incurred additional costs and from now until they are retired in 2010, the space shuttles will be chiefly devoted to supporting the International Space Station.
The ISS, itself — whose costs will likely run well over $100 billion by the time it is completed — has been a major failure. Originally it was envisioned to house dozens of scientists and astronauts and to serve as a scientific lab, a space factory and a platform for eventually launching manned missions to Mars.
But spiraling costs and other problems led them to cut the crew size for the completed station to six and it is currently occupied by only two individuals, whose time is mostly spent on repair and maintenance, leaving little capacity for conducting scientific investigations.
Last year, the president proposed that the U.S. launch a grandiose new program to establish an occupied moon base and, beyond that, to pursue a long term goal of sending human beings to Mars. The costs of establishing and maintaining a moon base could themselves be several times greater than the ISS, but even these will pale beside the costs of sending and protecting humans on the 18-month to two-year, 560-million mile round trip to Mars.
And all of this for what? Per dollar spent, the president's immensely costly lunar and Mars projects would produce slim gains by way of advancing scientific knowledge, while draining large sums from NASA's truly productive scientific missions now carried out with unmanned vehicles.
The lunar-Mars program should be considered only if it demonstrate that the huge cost will generate greater advances in scientific knowledge than the same money devoted to NASA's scientific activities using unmanned vehicles. Given the proven success of the scientific program to date, I am confident the lunar-Mars program will be found wanting and by a large margin.
How about the manned space program simply as a grand spectator sport? The first manned flight to Mars would indeed be watched with excitement by billions of people. But the excitement soon dies. After 1972, the last three Apollo flights that had been planned for the moon were canceled, largely because the country was no longer interested.
This was also the fate of the shuttle once it had flown the first few times.
Given the budget deficits the country faces over the next decade and the much larger problems posed by Social Security and Medicare in subsequent decades, we can ill afford to waste increasing billions of dollars on losing investments like the manned space program and especially on the massive expense of a lunar base followed by a trip to Mars.