New U.S. space rockets include crew-escape systems
Orion spacecraft's Launch Abort System can eject crew capsule in milliseconds
Heeding a lesson from history, designers of a new generation of U.S. rockets will include escape systems to give crew members a fighting chance of surviving launch accidents such as the one that felled an unmanned Orbital Sciences Antares rocket on Tuesday.
The U.S. space agency NASA bypassed escape systems for the now-retired space shuttle fleet, believing the spaceships to be far safer than they turned out to be. The illusion was shattered on Jan. 28, 1986, when gas leaking from a solid-fuel booster rocket doomed the shuttle Challenger and its seven crew about 72 seconds after liftoff from the Kennedy Space Center in Florida.
Taking a page from design books for the 1960s-era Mercury and Apollo capsules, the National Aeronautics and Space Administration's next manned spaceship, Orion, will include a rocket-powered tower attached to the top of the spacecraft that can separate from a troubled launch vehicle and parachute the crew to safety.
The so-called Launch Abort System can activate in milliseconds, catapulting the crew capsule about 1.6 kilometres in altitude in seconds.
"We proved in shuttle that it was a bad idea to not have a launch escape system ... so there's been a lot of work to build this really Cadillac version of a launch escape tower that they've got on Orion," said Wayne Hale, a former NASA space shuttle program manager who oversees human space flight for Colorado-based consulting firm Special Aerospace Services.
Huge, steerable escape capsule
"It's a big, heavy capsule that requires a big, heavy rocket that steers you all over the sky to get away from problems with the big rocket booster. It's a huge system," Hale said.
While Orion is intended for deep-space missions beyond the International Space Station, which flies about 418 kilometres above Earth, NASA is requiring commercial companies hired to taxi astronauts to and from the orbital outpost to have launch escape systems as well.
Privately owned Space Exploration Technologies, or SpaceX as the California-based firm is known, next year will test an alternative technology that uses its capsules' own steering thrusters to boost it away from a malfunctioning rocket.
Boeing plans to use a similar pusher abort system for its CST-100 capsule. SpaceX and Boeing last month won contracts worth a combined $6.8 billion US to finish development of their passenger spaceships, test them and fly up to six operational missions each for NASA beginning in 2017.
Currently station crew members fly on Russian Soyuz capsules equipped with Apollo-style rocket-powered launch escape towers. In 47 years of Soyuz rocket flights, the escape system has been used once in an actual emergency.
On Sept. 26, 1983, a fuel leak sparked a fire on the launch pad that engulfed a Soyuz rocket about a minute before liftoff. Seconds before the booster exploded, the rocket's launch abort system ignited, carrying cosmonauts Gennadi Strekalov and Vladimir Titov to safety.
"The interesting thing on the Soyuz then and even today is the crew can't initiate the launch escape tower, unlike the American designs. The ground control has to actually initiate it," Hale said.
"I would tell you that just because you've got a launch escape tower on your rocket doesn't mean that you're guaranteed safety," he added.
Space shuttles has 2 fatal accidents in 135 flights
NASA wants its commercial space taxis to be 1,000 times safer than the shuttle, which had two fatal accidents out of 135 flights.
The cause of the Orbital Sciences Antares rocket explosion remains under investigation. The accident, which occurred about 10 seconds after liftoff from the Wallops Flight Facility on Wallops Island, Virginia, claimed a cargo ship bound for the space station, which is a $100 billion research laboratory owned and operated by 15 nations.
The Antares rocket, which previously made four successful flights, has been grounded pending results of the investigation.
Orbital Sciences uses refurbished Soviet-era motors for the rocket's first stage and already had been planning to replace the engines, known as AJ-26, due to technical concerns and supply limitations.
"It is possible that we may decide to accelerate this change if the AJ-26 turns out to be implicated in the failure, but this has not yet been decided," Orbital Sciences President and Chief Executive David Thompson told analysts in a conference call on Wednesday.
"Under the original plan we were, as of now, about two years away from conducting the first launch of Antares with the second-generation propulsion system ... I certainly think we can shorten that interval, but at this point I don't know by how much," Thompson said.