Capsule safety system ready for testing in New Mexico
BY STEPHEN CLARK
Posted: May 5, 2010
NASA is planning a $220 million test Thursday of a new abort system that would whisk astronauts away from a failing rocket booster, but further work on the safety mechanism is on hold as managers divert funding for the project amid a shake-up of the space agency's exploration plans.
Although Thursday's test flight was originally developed under the cancelled Constellation program, NASA is selling the 97-second mission as critical to improving astronaut safety.
"You have to get the crew away from a launch vehicle that's already traveling extremely fast," said Mark Geyer, NASA's Orion project manager. "The launch abort system has to have very high energy and very high thrust. It has to be faster than the rocket, which is already going darn fast."
President Obama last month announced he plans to reshape the Orion capsule, originally a ship capable of going to the moon, into a lifeboat for astronauts on the International Space Station. Under such a scenario, Orion craft would launch unmanned on expendable rockets, eliminating the need for a crew escape system.
NASA has not designed and tested a launch crew escape system since the Apollo program in the 1960s. The space shuttle does not carry an abort system to shepherd astronauts away from the rocket during launch.
The Orion Launch Abort System could find its way to new commercial vehicles under study to carry U.S. astronauts to the space station.
Orbital Sciences, the escape system's prime contractor, believes the design is applicable to a range of new spacecraft.
"With regard to our future activities on the Orion launch escape system, we are anticipating that work will ramp down this year," said David Thompson, Orbital's chairman and CEO. "However, the technology that we have developed and the know-how that we have accumulated in astronaut safety systems, particularly during ascent phases of missions, should position us very well to develop and provide modified versions of the system that we have developed for Orion for our own and potentially for other commercial crew systems in the future."
NASA officials agree the system will test technologies vital to commercial space endeavors.
"The beauty of Pad Abort 1 is it puts all the key elements together and launches them in this extreme environment. That's going to apply to anybody," Geyer said. "All those elements on going to be needed, no matter who does this job."
During Thursday's test, three new solid rocket motors never tested in flight will shoot a boilerplate capsule more than a mile in altitude, keep the craft on course, then jettison the abort tower. Parachutes are supposed to deploy to gently guide the capsule back to Earth nearly a mile from the launch pad.
The flight will simulate an abort from the launch pad due to a major rocket mishap before liftoff.
"Pad abort is a stressing case because we need to get high enough and far enough away so the parachutes can do their job," Geyer said. "In real life, you could abort off the pad because you don't have time to get the crew out and there's something wrong with the launch vehicle."
Standing more than 50 feet tall, the test vehicle will reach 445 mph in three seconds and a mile in altitude a few moments later, according to NASA.
"We get to that first mile pretty darn quick, going straight up," Geyer said.
The capsule will be accelerated at 15 g's and the abort motor produces about 163 decibels of noise at the top of the spacecraft, nearly loud enough to kill hearing tissue.
A powerful solid rocket motor will briefly ramp up to 500,000 pounds of thrust to propel the vehicle off the pad, burning about 4,000 pounds of propellant in three seconds. The abort rocket will burn out about six seconds after blasting off from the desert floor.
At the same time the abort motor ignites, an attitude control rocket will also fire. The attitude motor will keep the slender craft on course by alternating thrust through eight rocket nozzles around the circumference of the abort system.
"You'll be able to see the attitude control motor doing its thing, changing the thrust depending on which way we need to fly," Geyer said.
Two drogue parachutes should be deployed less than 25 seconds into the launch, and three 116-foot-wide main chutes will be unfurled about six seconds later.
"We open them to different sizes on a specific schedule to slow the vehicle down enough and also not to put too much load on the parachutes," Geyer said.
The capsule is expected to touch down about 4,700 downrange from the launch pad.
Geyer said he would consider the test successful if the rockets keep the craft under control through the point where the abort tower should be jettisoned. The subsequent deployment of drogue and main parachutes are gravy, Geyer said.
Launch controllers inside a mobile van at White Sands will monitor winds from the surface to about 6,000 feet during the countdown. Wind speed and direction are expected to be the only weather issues that could halt the launch.
ATK built the primary abort and attitude control motors, and Aerojet provided the jettison motor fired last in the abort sequence.
Under orders from NASA, Orion lead contractor Lockheed Martin sent a letter to abort system partners last month calling for a freeze of most work on the apparatus by April 30. An exception was made for work directly related to Thursday's abort test launch.
NASA officials say the orders to hold work on the abort system were unrelated to Obama's decision to retool Orion, which followed the White House's original plan to scrap Orion altogether.
"The good news is that the launch abort system you're going to see Thursday is coming along very well," Geyer said in an interview Monday. "The difficult news is I'm probably going to have to slow them down because the other parts of the system -- the avionics, life support and other things that we need for Orion -- are a little bit behind."
Managers made the decision as funding for the Orion capsule, as well as the rest of the cancelled Constellation program, is siphoned into new projects.
"What you see in the letter is prioritizing the effort to get the other system that need more work on them to have the money in 2010, and reduce the money for the stuff that's a little bit ahead," Geyer said. "It's certainly not the optimum way to develop a vehicle, but they are choices we have to make."