GREENBELT, Md. — NASA’s decision to reinstate a Hubble Space Telescope servicing mission canceled nearly three years ago, while widely praised, is not without ripple effects for some other agency programs.

NASA Administrator Mike Griffin’s Oct. 31 announcement that space shuttle astronauts would be sent to refurbish Hubble as soon as May 2008 was met with a standing ovation from the large crowd assembled here at the agency’s Goddard Space Flight Center, which operates the legendary space telescope.

Griffin emphasized that the decision to go ahead with the mission was made only after a lengthy analysis of the risks. That analysis led agency officials to conclude that Hubble’s life can be extended to 2013 or later without posing undue danger to the lives of the seven astronauts who will perform the repairs and upgrades.

“While there is an inherent risk in all spaceflight activities, the desire to preserve a truly international asset like the Hubble Space Telescope makes doing this mission the right course of action,” Griffin said.

Griffin’s acknowledgment that conducting the mission would have a slight impact on development of the shuttle’s replacement, the Ares 1 Crew Launch Vehicle, did nothing to dampen the mood; nor did his later admission that the agency must still decide how to cover the cost of the mission, which he estimates at $900 million.

“This is a great day for Maryland, a great day for science, a great day for discovery, [a] great day for Goddard and a great day for science education,” said U.S. Sen. Barbara Mikulski (D-Md.), who led the charge to reinstate the mission. Mikulski wielded her clout as a senior member of the Senate Appropriations Committee to keep the Hubble repair team together during the nearly three years the mission remained in limbo.

Mikulski praised Griffin and NASA for making sure the astronauts conducting the Hubble refurbishing mission will be safe. “Your safety has always been No. 1 and your safety and your lives will continue to be No. 1,” Mikulski said in remarks directed at the astronauts.

NASA scrapped the long-planned fifth and final Hubble servicing mission in early 2004 on the grounds that complying with safety recommendations made in the wake of the 2003 Space Shuttle Columbia disaster would require developing a unique set of shuttle inspection and repair techniques and tools that would not be needed for missions to the international space station.

NASA also pointed out at the time that a shuttle crew sent to service Hubble would not have the option of going to the space station to await rescue should their orbiter be deemed unfit to return to Earth.

To address that concern, NASA now plans to keep a second shuttle on standby to mount a rescue mission in the unlikely event the Hubble crew becomes stranded in orbit.

Keeping that second shuttle on standby could force the delay of an early test of the Ares 1 launcher, a key element of the shuttle’s replacement system being developed under NASA’s Constellation Program.

Although the early test, dubbed Ares 1-1, is not slated to occur until April 2009, NASA had planned to hand over Launch Pad 39-B at the Kennedy Space Center to the Constellation Program next year to begin the modifications needed for the flight.

Griffin said NASA’s associate administrator for exploration systems, Scott Horowitz, and his team accepted the decision to keep Pad 39-B configured for shuttle launches longer than originally planned and are studying how that will affect the Ares test schedule. William Gerstenmaier, NASA associate administrator for space operations, told reporters Oct. 31 that it may be possible to make some Ares-driven modifications to pad 39-B and still use it to stage a possible shuttle rescue mission.

NASA also must still sort through the budget impacts of the Hubble repair mission.

Griffin said about half of the mission’s $900 million price tag is money the agency already has spent: $200 million building the two new Hubble instruments and hardware ; and $200 million to $250 million keeping the Goddard-based repair team together during the nearly three years the mission had been on appeal.

Griffin said the remaining costs include about $200 million for shuttle hardware and launch processing, and $200 million or more to keep the Hubble repair team intact through the mission. 

Although the space shuttle program may absorb some of those costs , the burden is expected to fall most heavily on NASA’s roughly $900 million-a-year astronomy and astrophysics budget. This budget already is under pressure from cost growth on Hubble’s successor , the flagship-class James Webb Space Telescope, and the airborne Stratospheric Observatory for Infrared Astronomy (SOFIA), which recently escaped a close call with the budget ax.

Speaking the day after the Hubble announcement at a space exploration seminar at George Mason University’s Arlington, Va., campus, NASA Deputy Administrator Shana Dale cited Hubble costs among the reasons the agency has decided to indefinitely postpone two long-proposed astronomy missions.

“NASA simply cannot afford every mission that every astronomer would like us to do as soon as they would like us to do it,” she said. “With significantly underestimated costs for the James Webb Space Telescope, additional costs for the next Hubble Servicing Mission and continuation of the SOFIA program, we decided the best course was to turn the Space Interferometry Mission and Terrestrial Planet-Finding missions into technology development efforts for the time being.”

NASA’s relationship with Hubble has been long and storied. Initially considered a costly failure when it launched in late April 1990 with a flawed primary mirror, it has since been lauded as NASA’s most successful scientific endeavor.

The first servicing mission repaired the faulty optics by installing what Mikulski called “the most expensive contact lens ever built.” Three additional servicing missions were conducted over the years to add new instruments and other components, including the gyroscopes used to orient the telescope.

The upcoming servicing mission will outfit Hubble with two new instruments, replace its gyroscopes and batteries, and make several other repairs, including a first-of-its-kind attempt to revive an instrument not designed to be serviced in space.

NASA intends to launch the 11-day repair mission during a six-month window that opens in May 2008.

Hubble has been operating on two gyroscopes instead of the prescribed three since August 2005, when NASA decided to switch one off and hold it in reserve. Because that gyroscope now serves as a spare, NASA expects Hubble to be able to continue science observations through mid-2008.

Without new gyroscopes, however, NASA estimates that Hubble has only 50-50 change of remaining in service beyond October 2008. But even if Hubble were to lose two or even all of its gyroscopes before the repair mission is mounted, NASA would be in no danger of losing control the telescope , said Preston Burch, NASA’s Hubble program manager. Though science operations would cease, Burch said, NASA could continue to fly Hubble on one working gyroscope or possibly even no working gyroscopes.

A total battery failure, however, would be fatal. Hubble’s six batteries, all original equipment, have only about half of their original charge capacity and are not expected to last much beyond 2009, Burch said. He added, however, that predicting battery life is more art than science. Once the batteries go, Hubble’s onboard heaters would shut down and within a couple of days the telescope would freeze beyond repair, NASA engineers estimate.

Once fully refurbished and outfitted with two new instruments – the Wide Field Camera 3 and the Cosmic Origins Spectrograph, both built by Boulder, Colo.-based Ball Aerospace and Technologies Corp. — Hubble is expected to be at the peak of its capabilities and remain in service until 2013 and perhaps much longer.

The telescope also would have its largest complement of working science instruments since 1993, assuming efforts to bring the Space Telescope Imaging Spectrograph back on line are successful. That instrument failed in 2004 and NASA plans to devote a full day of spacewalks to try and repair it.

Amid the excitement about the upcoming mission, NASA officials cautioned that there is much work to be done.

“You never celebrate until you succeed; we all celebrated on the launch of Hubble in 1990 … the champagne does not get opened until the servicing mission is over. I’ve learned that lesson too many times,” said Ed Weiler, director of Goddard and a Hubble program scientist when the observatory was launched .

 

Hubble Servicing Mission at a Glance

 

PRIVATE colorchange:<c”Black”> Hubble-bound shuttle astronauts have a daunting task ahead of them. Their tasks include:

  • Installation of the Wide Field Camera-3, a new camera to improve Hubble’s vision.
  • Replacement of Hubble’s batteries, some thermal insulation and a broken guidance sensor.
  • Refurbishment of the Hubble’s vital attitude control gyroscopes, which are used to orient the space telescope. Only two of the six are currently in operation. Two are being held as spares while two others are broken.
  • Installation of the Cosmic Origins Spectrograph and the unprecedented repair of Hubble’s Space Telescope Imaging Spectrograph, which was never designed to be serviced in orbit.
  • Using the shuttle’s engines to boost Hubble into a slightly higher orbit.