KENNEDY SPACE CENTER, Fla.--Running two weeks late because of an electrical glitch, the repaired shuttle Endeavour finally blasted off and rocketed into orbit for the last time Monday, putting on a spectacular, if brief, show for the several hundred thousand spectators who were estimated to have come to watch NASA's next-to-last shuttle launch.
Carrying a $2 billion particle physics experiment, critical supplies, and spare parts bound for the International Space Station, Endeavour's three main engines flashed to life and throttled up to full power while computers monitored their performance 50 times per second.
Six-and-a-half seconds later, at 8:56:28 a.m. EDT (GMT-4), Endeavour's twin solid-fuel boosters ignited with a rush of 5,000-degree exhaust, instantly pushing the spacecraft away from pad 39A.
Accelerating through 100 mph--straight up--in just eight seconds, Endeavour climbed away and quickly disappeared from view as it knifed through low-level clouds, wheeling about to line up on a northeasterly trajectory paralleling the East Coast.
Shuttle commander Mark Kelly's wife, Arizon Rep. Gabrielle Giffords, watched Endeavour's ground-shaking takeoff from the roof of the Launch Control Center 3.4 miles from pad 39A, with her mother, Mark Kelly's twin brother Scott, and other family members. Giffords was shot in the head during a January assassination attempt and her recovery has generated intense media interest.
She flew to Florida for Endeavour's initial launch attempt April 29, but the ship was grounded by an electrical problem with the shuttle's hydraulic system. She flew back Sunday for Kelly's second launch try; privacy screens shielded her from view. A spokeswoman said she was relieved Endeavour got off, saying "good stuff" after the shuttle climbed away.
"I think relief was her biggest feeling," said Pia Carusone, Giffords' chief of staff. "She was very proud, is always proud of Mark and what he does; it was an exciting moment for her to watch."
The early stages of Endeavour's climb to space appeared normal as the shuttle rocketed away atop a churning cloud of exhaust from its solid-fuel boosters. Two minutes and five seconds later, the boosters, their propellant depleted, were jettisoned, falling to the Atlantic Ocean 30 miles below where recovery ships were standing by.
Endeavour continued toward orbit on the power of its three hydrogen-fueled main engines.
A camera mounted on the side of the ship's external tank showed spectacular views of the clouds dropping away below and later. No major debris could be seen falling away from the tank during the first two minutes and 15 seconds of flight, when the dense lower atmosphere can cause high-velocity impacts with the shuttle's fragile heat shield.
But Bill Gerstenmaier, chief of space operations at NASA headquarters, said engineers spotted two small pieces of foam insulation falling away between two minutes and 6 seconds into flight and two minutes and 14 seconds. He said neither piece appeared to strike the orbiter, but engineers will carry out a detailed photo assessment as usual.
Endeavour's external tank--ET-122--was damaged when a roof collapsed at the Lockheed Martin Michoud Assembly Facility manufacturing plant in New Orleans. The tank was repaired, but NASA managers said before launch they expected to see more foam than usual break away during launch. But overall, the tank appeared to perform well and 8.5 minutes after liftoff, Endeavour separated and slipped into its planned preliminary orbit. Scott Kelly gave Giffords and Mark Kelly's two daughters red roses after the shuttle's main engines shut down.
"There were hugs all around, absolutely, it was very celebratory," Carusone said.
Mike Moses, chairman of NASA's Mission Management Team, said the countdown and launch went well and jokingly apologized for the low clouds that obscured the view of most spectators.
"It was a fantastic launch, a really great day for us, a good example of us watching the weather and getting right down to our flight rule and our launch commit criteria limits," he said. "And you can see we don't have any flight rules or launch commit criteria that dictate how long you can see the launch before it goes out of sight!"
Kelly, pilot Gregory Johnson, European Space Agency flight engineer Roberto Vittori, and Mike Fincke, veteran of two previous long-duration stays aboard the International Space Station, made the climb to orbit strapped into seats on Endeavour's upper flight deck.
Strapped in on the shuttle's lower deck were Andrew Feustel and Gregory Chamitoff, another station veteran.
After adjusting the shuttle's orbit, the astronauts opened Endeavour's cargo bay doors around 10:15 a.m. and began rigging the ship for orbital flight, breaking out computers and other gear as they worked through a busy first few hours in orbit.
If all goes well, Kelly will guide Endeavour to a docking at the space station's forward port around 6:15 a.m. Wednesday. A pallet of spare components will be robotically bolted to the left side of the station's power truss a few hours later. The next day, the 7.5-ton Alpha Magnetic Spectrometer, the mission's showcase payload, will be attached to the right side of the power truss.
Using a massive magnet to bend the trajectories of high-energy cosmic rays--charged particles from supernovas, neutron stars, black holes, and other cosmic enigmas--scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the mass of the universe.
AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth--or something completely unexpected.
The AMS "really probes the foundations of modern physics," said Sam Ting, a Nobel laureate who manages the multinational experiment. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena that exist in nature but yet we have not the tools or the imagination to find."
AMS will operate autonomously after it is connected to station power, beaming down a continuous stream of data for at least 10 years and possibly longer if the lab is funded past 2020.
Fincke, Feustel and Chamitoff, working in alternating two-man teams, plan to carry out four spacewalks--on May 20, 22, 25, and 27--to retrieve one experiment on materials science exposure and to install another; to refill the ammonia coolant reservoir in the station's far left-side solar array; to lubricate a solar array rotary joint; to install a robot arm attachment fitting on the Russian Zarya module; and to perform needed maintenance.
Endeavour is scheduled to land back at the Kennedy Space Center around 2:32 a.m. on Wednesday, June 1.
"It is an extremely complex mission," said shuttle Program Manager John Shannon. "It's a long period of time docked to the station, four EVAs, a tremendous amount of activity internal to the ISS, we're going to put a world-class experiment on the ISS and get it all hooked up.
"I think the missions we are executing now in complexity are the most difficult missions that not just NASA, but any nation has ever flown in space. And I would include Apollo in that discussion. I think the missions we do right now are more complicated than what we were doing even during the moon landings."
NASA attempted to launch Endeavour April 29, but the countdown was called off when a "string" of fuel line heaters used by one of the shuttle's three hydraulic power units failed to activate.
Engineers were unable to immediately determine what might have caused a short in a power switching box in the shuttle's aft engine compartment. Playing it safe, the box, called an aft load control assembly, was replaced, along with thermostats and associated wiring.
While that work was going on, engineers reviewing data from thermostat tests last June noticed a brief, previously undetected current spike. A close inspection of the thermostat in question revealed damaged insulation and an exposed conductor.
Engineers believe the exposed conductor likely triggered the short that prevented the heaters from powering up April 29. The repaired heater system worked normally during the countdown Monday and there were no obvious problems during the climb to space.