Space Shuttle

GREENBELT -- Now that NASA has the green light to launch astronauts on one final servicing mission to the Hubble Space Telescope, scientists and engineers in Baltimore, Greenbelt and elsewhere will have just 18 months to perfect their plan for pulling it off. A critical part of that plan will be preparing a rescue shuttle to be fueled and poised on a second launch pad, ready to fly if the Hubble repair crew is stranded in orbit. Although all flights will continue to be risky for their crews, "the space shuttle can be flown safely if we are very careful.

CAPE CANAVERAL, Fla. -- Space shuttle Atlantis is heading home this morning after a late inspection of the ship's heat shielding yesterday found nothing wrong. The inspection was prompted by Tuesday's sighting of an unknown object that apparently shook loose from Atlantis during prelanding checkouts of the shuttle's body flaps and steering thrusters. Eight hours of surveys using cameras on Atlantis' robot arm and a sensor-laden 50-foot boom did not detect any sign the object was dislodged from the ship's critical heat armor.

HOUSTON -- Two astronauts will venture outside the International Space Station today to dangle from the end of a 100-foot pole that could be used to make repairs to the heat shield of the space shuttle Discovery, which is docked to the station. Piers Sellers and Mike Fossum are scheduled to begin their planned 6 1/2 -hour excursion outside the spacecraft, which is docked to the International Space Station, about 9:15 a.m. In addition to performing maintenance on the station, the astronauts will conduct a test by alternately standing in foot restraints at the end of a boom held by shuttle Discovery's robotic arm. The boom and the arm are each 50 feet long.

CAPE CANAVERAL, Fla. -- The crew of the shuttle Discovery docked with the International Space Station yesterday and prepared for a "focused inspection" today of several potential problem areas that have cropped up on the shuttle. NASA officials kept open the possibility of a spacewalk later in the mission to remove two bulging gap fillers, spacers placed between the shuttle's heat-resistant tiles. On the whole, NASA managers continued to portray the mission and the soundness of the shuttle in glowing terms.

CAPE CANAVERAL, Fla. -- The space shuttle Discovery was rolled out to its launch pad at Kennedy Space Center yesterday amid growing optimism that the mission will be ready for a July 1 liftoff. The biggest threat to the launch date remains uncertainty about whether the shuttle's external fuel tank is safe to fly after the removal of a foam ramp from the tank's exterior. The ramp was taken off after a 1-pound piece broke free during Discovery's launch last July and narrowly missed the shuttle.

CAPE CANAVERAL, Fla. -- NASA managers said yesterday that there would be no more major safety changes to the space shuttle's external fuel tank until after the next planned launch in July. The decision follows a debate among engineers on whether to modify so-called ice-frost ramps on the tank's exterior before Discovery's coming flight. The small ramps are crafted from foam insulation that is sprayed by hand on the tank's exterior to prevent the buildup of ice. Concern remains among some engineers that in a worst-case scenario, pieces of the ramp weighing 2 or 3 ounces could break off during launch and hit the orbiter, causing critical damage.

CAPE CANAVERAL, Fla. -- The children of the seven astronauts who died aboard shuttle Columbia three years ago received condolences from around the world, but one heartfelt message was especially unique. The letter, written by Challenger commander Dick Scobee's daughter, Kathy, spoke of the difficulty of dealing personally with a tragedy so public. "Everyone in the country felt like it happened to them too," she wrote. "And it did. The Challenger explosion was a national tragedy. Everyone saw it. Everyone hurt.

ORLANDO, Fla. - NASA remains hobbled by the flawed leadership style and engineering practices that led to the Columbia disaster, according to members of an independent group that monitored the agency's safety efforts after the shuttle disintegrated during re-entry in 2003. Overall, the watchdog panel's final report yesterday found that NASA had made significant strides to correct the conditions that led to the deaths of the seven astronauts aboard Columbia. But seven of the group's 26 members delivered a separate assessment describing lingering problems in every aspect of NASA's efforts to return the space shuttle to flight.

CHICAGO - NASA's deliberations about when to resume space shuttle flights bring to mind the New Yorker cartoon of an executive on the phone, looking at his calendar and saying, "How about never? Does never work for you?" After spending 2 1/2 years and huge amounts of money to prevent a recurrence of the problem that destroyed the last shuttle, the agency now finds the problem has recurred. If NASA takes appropriate action, though, it won't happen on the next shuttle flight, because there won't be a next shuttle flight.

ORLANDO, Fla. - NASA sailed through launch preparations yesterday while the crew of the space shuttle Discovery practiced landings and got ready for their planned historic mission this week. Top managers met at the Kennedy Space Center to discuss technical issues but emerged with no immediate showstoppers. Liftoff is scheduled for 3:51 p.m. tomorrow. "We've had a series of discussions over the past several weeks, going over all the risks" involved in a shuttle flight, said Wayne Hale, NASA's deputy shuttle program manager.