By Marc Kaufman
Washington Post Staff Writer
Sunday, October 29, 2006; A03
As NASA learned when it canceled a planned shuttle mission to keep alive the Hubble Space Telescope almost three years ago, its orbiting source of jaw-dropping intergalactic images and deep insights into the early days of the universe had become something of an astronomic rock star.
The scientific and public response was overwhelming: The then-14-year-old Hubble had to be saved before its batteries and gyroscopes failed, and NASA was seriously misguided for refusing to send a shuttle crew to keep it running. This view was strongly endorsed by an expert panel convened by the National Academy of Sciences in late 2004.
Soon after, Michael D. Griffin became NASA administrator and agreed to reconsider the Hubble mission. On Tuesday, he will announce whether the telescope will be repaired or will be allowed to gradually run out of steam.
NASA said Friday that a series of events and briefings will follow the announcement at Goddard Space Flight Center in Greenbelt -- the kind of activity that often accompanies a decision to go ahead with a big mission. But agency officials said that no decision had been reached and that Griffin will study the pros and cons over the weekend.
"Every scientist on the face of the globe, and many people in the general public, are watching this, looking forward to a decision," said Mario Livio, head of the science program at the Space Telescope Science Institute in Baltimore, which manages the Hubble's scheduling and research for NASA. "I'm cautiously optimistic, but there are so many factors involved."
For Griffin, it is a tough choice -- balancing the undeniable success of the Hubble against the equally undeniable risks to the astronauts who would fix it, as well as the unforgiving schedule of shuttle flights needed to complete the international space station.
The decision by his predecessor, Sean O'Keefe, to scrub the Hubble repair mission was made after the 2003 Columbia disaster, when it was not clear when the shuttles would get back into space.
Griffin has often said that he believes the telescope is one of the great scientific instruments of all time and that it deserves to be repaired.
"If we can do it safely, we want to do it," Griffin said at a September briefing after the successful landing of the space shuttle Atlantis. "But we have new constraints on . . . the space shuttle system. We have a new understanding of its fragility and vulnerability."
An aerospace engineer, Griffin worked for two years in the early 1980s on issues related to the Hubble project.
Among the major constraints are that the space shuttle fleet is aging fast and that NASA is eager to finish assembly of the space station by 2010, so the three remaining spacecraft can be retired. A mission to Hubble could interfere with the schedule.
After two fatal shuttle disasters, NASA is also increasingly focused on safety and on having backup systems for crews if their spaceship gets damaged. In theory, the international space station is the standby shelter for a spacecraft in trouble, but it would be unreachable on a flight to the Hubble. That is because the orbits of Hubble and the space station are very different, and a shuttle launched to the Hubble would not have the fuel and power to shift orbits to reach the station.
As a result, the crew of a Hubble-bound shuttle has only about three weeks' time to repair any damage to the spaceship. That would hardly leave time for the final contingency, preparing and launching a second shuttle for a rescue mission.
"We've had three successful shuttle missions since Columbia, and we've learned a lot about inspecting and repairing the vehicle," NASA spokesman Allard Beutel said. "So we have a lot more capability and flexibility, but clearly some safety issues remain."
Griffin met with his top lieutenants Friday for a final discussion of whether the mission can be done safely and without too much disruption to the space station assembly schedule.
Reflecting Griffin's hope to make room for the mission, a Hubble launch has been penciled in for spring 2008, though officials say the date is a place-holder rather than a sign that a positive decision has been made.
The Hubble, which has been repaired and upgraded four times by astronauts since it was launched in 1990, has had a remarkable record of scientific breakthroughs.
Because it orbits 380 miles above Earth, away from the haze of the atmosphere, it can identify and photograph distant galaxies and matter never before examined. Astronomers have used Hubble images to fix the age of the universe at 13.7 billion years, to discover massive black holes at the center of many galaxies, and to explore a mysterious force called dark energy, which, by acting against the forces of gravity, is causing the universe to expand. Livio of the Space Telescope Science Institute said dark energy is probably the most significant issue in physics today, and losing Hubble would freeze promising research into its nature for as much as a decade.
But some believe Hubble's greatest accomplishment lies in a less rarified realm -- that it has greatly popularized astronomy with its stunning and awe-inspiring images of the universe.
Each of the four earlier Hubble repair missions included some upgrading of instruments, and a possible fifth mission would similarly increase its capacities. Two powerful -- and very expensive -- instruments have been manufactured specifically for the Hubble. They would greatly increase the telescope's ability to look deep into space and to study the chemical composition of the far-distant gas between galaxies.
Livio said the unprecedented power of the new Wide Field Camera 3 would, for instance, enable astronomers to learn about even earlier phases of the universe's formation by making observations in the infrared and ultraviolet wavelengths. The new Cosmic Origins Spectrograph will examine the subatomic baryon particles that inhabit the space between galaxies. The instruments cost $200 million and may have no other use if they cannot be delivered to the Hubble, Livio said.
If Hubble is not repaired, NASA estimates that it will probably keep working into 2008 or 2009. The James Webb Space Telescope, a replacement of sorts but with different capabilities, is scheduled to be launched in 2013.
NASA officials say the Hubble repair decision will be made on the basis of safety, engineering and scheduling concerns, but it will also say a lot about NASA's priorities. The speed-up in assembly of the space station is both because it is well behind schedule, and because NASA is eager to get out of the space shuttle business so it can focus on President Bush's initiative to return to the moon by 2020 and then explore Mars.
The costs of both the shuttle program and the new manned exploration mission are great, and NASA has said the basic science budget will grow more slowly or be cut as a result. Because the telescope is one of the gems of the NASA science directorate, some see the fate of Hubble as indicative of where the agency is headed.
"This is a terribly important decision, and it has so many political and scientific overtones," said J. Craig Wheeler, astronomy professor at the University of Texas at Austin and president of the American Astronomical Society.
"It's very important for those who want to continue working with Hubble, important for those who want to do other space science, and it's important as an indication of that evolving balance between space science and human space exploration," he said. "And it shows that NASA has an enormous number of big issues on its plate right now."
