Hubble Servicing Mission Opens Space Shuttle's Last Act
Tuesday, May 12, 2009
CAPE CANAVERAL, May 11 -- Almost overlooked in the hoopla over Monday's launch of the final servicing mission to the Hubble Space Telescope has been another piece of gee-whiz space technology that will soon be only a museum exhibit: the space shuttle.
There are only nine shuttle missions left, including the one that started when Atlantis blasted off through a thin layer of clouds drifting high above the Kennedy Space Center. Astronauts plan to latch onto the Hubble on Wednesday and then, early Thursday, begin a series of spacewalks in which they will replace, and in some cases repair on the spot, many of the telescope's scientific instruments.
The remainder of the shuttle flights will be to the international space station, with the final mission scheduled for late 2010. The Hubble mission is thus one of the shuttle's last hurrahs, and nothing quite like it will happen again any time soon.
The Hubble was dreamed up in the 1970s at the same time as the space shuttle program, and the telescope and the space truck have always been symbiotic. No other space telescope gets serviced by astronauts. NASA currently has a dozen of them in orbit, many of them in orbits far from where the shuttle can fly. They were not designed with the thought that anyone would ever show up to fix them.
"Hubble was lucky," said Edward Weiler, NASA's head of space science, who has worked on the Hubble project since 1978. The shuttle, he said, "gave you an infrastructure that was there and was frankly free to the science side."
The senior project scientist for Hubble, David Leckrone, who started on the telescope in 1976, said, "The dream was that Hubble would be similar to mountaintop telescopes." The greatest mountaintop telescopes last for decades. The Hubble made that concept come true in space.
But other space telescopes have been designed for just a few years of operation. Servicing by astronauts is too costly and dangerous. The successor to the Hubble will be an infrared telescope a million miles from Earth, and although it has a docking ring, it is much more likely to be serviced robotically than by human beings traveling all that way in a spaceship.
NASA's next-generation launcher, the Ares I, could not possibly duplicate the feats of the aging shuttle, NASA Associate Administrator Bill Gerstenmeier noted at a post-launch briefing Monday.
"The space shuttle is really uniquely set for this servicing task," he said. Atlantis carries not only seven astronauts but also, on this mission, 22,000 pounds of instruments, batteries and other cargo, vastly more than could be hauled by the skinny Ares 1. The shuttle's payload bay acts like a garage in space. And with its robotic arm, the shuttle can reach out and grab the huge telescope as surely as a frog nabbing a fly.
NASA's current plans call for separating astronauts from most of the cargo going into space. Astronauts will ride the Ares I, but cargo will go up on a larger, unmanned rocket, the Ares V.
The architecture of the next generation of spacecraft may yet change. The Obama administration last week ordered up a soup-to-nuts review of the entire human-spaceflight program. The review panel, headed by former aerospace executive Norman Augustine, will have 90 days to report back.
The announcement of that review alone was enough to throw a cloud of uncertainty over the NASA establishment. President Obama's budget proposal last week added another layer of puzzlement: Although it boosts funding for NASA over the next two years, it shows a drop-off in money for human spaceflight in the three years starting in 2011.