In the latest edition of The New York Review of Books, physicist, winner of the Nobel Prize, and author Steven Weinberg discusses NASA’s latest changes in plans after Bush jr decided to send people to Mars.

Excerpts:

“As far as I know there never has been a moment from Titov’s flight to the present when the ability to put people into space gave any country the slightest military advantage. I say this despite the fact that some military satellites have been put into orbit by the space shuttle. This could be done just as well and much more cheaply by unmanned rockets. It had been hoped that the shuttle, because reusable, would reduce the cost of putting satellites in orbit. Instead, while it costs about $3,000 a pound to use unmanned rockets to put satellites in orbit, the cost of doing this with the shuttle is about $10,000 a pound. The physicist Robert Park has pointed out that at this rate, even if lead could be turned into gold in orbit, it would not pay to send it up on the shuttle. Park could have added that in this case NASA would probably send lead bricks up on the shuttle anyway, and cite the gold in press releases as proof of the shuttle’s value. […]

“The Hubble Space Telescope is a special case. Like the other orbiting observatories, the Hubble operates under remote control, with no people traveling with it. But unlike these other observatories, the Hubble was not only launched by the shuttle, but has also been serviced several times by astronauts brought up to its orbit by the shuttle. The Hubble has made a great contribution to astronomy, one that goes way beyond taking gorgeous color photos of planets and nebulae. […] The Hubble may have given NASA its best argument for the scientific value of manned space flight. But like the other space observatories, the Hubble Space Telescope could have been carried into orbit by unmanned rockets. This would have spared astronauts the danger of shuttle flights, and it would have been much cheaper. Riccardo Giacconi, the former director of the Space Telescope Science Institute, has estimated that by using unmanned rockets instead of the space shuttle, we could have sent up seven Hubbles without increasing the total mission cost. It would then not have been necessary to service the Hubble; when design flaws were discovered or parts wore out, we could just have sent up another Hubble.

“What about the scientific experiments done by astronauts on the space shuttle or the space station? Recently I asked to see the list of experiments that NASA assigned to the astronauts aboard the Columbia space shuttle on its last flight, which ended tragically when the shuttle exploded during re-entry. It is sad to report that it is not an impressive list of experiments. Roughly half had to do with the effect of the space environment on the astronauts. This at least is a kind of science that cannot be done without the presence of astronauts, but it has no point unless one plans to put people into space for long periods for some other reason. Of the other half of the Columbia’s experiments, a large fraction dealt with the growth of crystals and the flow of fluids in nearly zero gravity, old standbys of NASA that have neither illuminated any fundamental issues of science nor led to any practical applications. […] Much of the ‘scientific’ program assigned to astronauts on the space shuttle and the space station has the flavor of projects done for a high school science talent contest. Some of the work looks interesting, but it is hard to see why it has to be done by people. For instance, there was just one experiment on Columbia devoted to astronomy, a useful measurement of variations in the energy being emitted from the sun. The principal investigator tells me that the only intervention of the astronauts consisted of turning the apparatus on and then turning it off. […]

“Two days after President Bush presented his new space initiative, NASA announced that the planned shuttle mission to service Hubble in 2006 would be canceled. This mission would have replaced gyroscopes and batteries that are needed to extend Hubble’s life into the next decade, and it would have installed two new instruments (which have already been built, at a cost of $167 million) to extend Hubble’s capacities. […] in about three years, when the Hubble gyroscopes can no longer point the telescope accurately, it will cease operation. This will leave us with no large space telescope until 2011 at the earliest. Eventually, before the slight drag of the Earth’s atmosphere at its altitude can bring the Hubble down, an unmanned rocket will be sent up to the Hubble to take it out of orbit and deposit it harmlessly into the ocean. Part of the increase in NASA’s spending for science will be about $300 million for destroying Hubble. NASA’s stated reason for terminating the Hubble while continuing work on the space station is that it is more dangerous for the shuttle to go up to Hubble than to the space station. Supposedly, if the astronauts on the shuttle find that damage has been done to the shuttle’s protective tiles during launch, they could wait in the space station for a rescue, while this would not be possible during a mission to the Hubble. But there are many other dangers to astronauts that are the same whether the shuttle is going to the space station or the Hubble Space Telescope. Among these is an explosion during launch, like the one that destroyed the Challenger shuttle in 1986. The New York Times Web site has carried a report from an anonymous NASA engineer who challenges NASA’s statement that a shuttle flight to Hubble would be more risky than a flight to the space station. He or she points out that the shuttle would be less exposed to micrometeoroids and orbital debris at the altitude of Hubble than at the lower altitude of the space station.”