The SpaceX "Grasshopper" rocket hovers over McGregor, Texas, on April 19, 2013, during a test flight (left). One of the Falcon 9 rocket landing legs on display at the SpaceX headquarters in Hawthorne, Calif. (right)
Space Exploration Technologies is installing landing legs on its next Falcon 9 rocket, part of an ongoing quest to develop boosters that fly themselves back to the launch site for reuse.
For the upcoming demonstration, scheduled for March 16, the Falcon 9’s first stage will splash down, as usual, in the ocean after liftoff from Cape Canaveral Air Force Station in Florida.
This time, however, SpaceX hopes to cushion the rocket’s destructive impact into the Atlantic Ocean by restarting the Falcon 9’s engine and extending landing legs that will be attached to the booster’s aft section. The goal is a soft touchdown on the water.
Falcon 9 “will continue to land in the ocean until we prove precision control” from hypersonic all the way through subsonic regimes, SpaceX founder, chief executive and design engineer Elon Musk said on Twitter.
SpaceX has been chipping away at that challenge in a related series of technology development initiatives.
In October 2013, SpaceX completed a program called Grasshopper to develop precision landing techniques. From a launch pad in McGregor, Texas, SpaceX flew a 10-story, first-stage Falcon rocket that ultimately reached an altitude of .46 miles (744 meters) before touching back down.
An expanded program is due to begin this year from a new test site at Spaceport America in New Mexico. The new prototype, known as Falcon 9R, will be outfitted with nine Merlin 1D engines, rather than just the single motor flown on Grasshopper, to reach higher altitudes and faster descent rates.
Next month’s test will be SpaceX’s second using an operational rocket.
The company’s September 2013 debut of its upgraded Falcon 9 rocket (flying for the first time from California) included a restart of the spent first-stage to slow the rocket’s descent.
The first of two planned engine restarts was successful. The second one failed because the rocket was spinning. Centrifugal force cut off the flow of fuel.
Musk said afterward that landing legs should help stabilize the rocket.
Four legs, which are made of carbon fiber with aluminum honeycomb, will be placed symmetrically around the base of the rocket. They will be stowed along the side of the vehicle during launch and extended down and outward for landing, SpaceX’s website shows.
Musk said the legs used for next month’s test will have a span of about 60 feet.
"Given all the things that would have to go right, the probability of recovering the first stage is low ... but we’re getting closer," SpaceX spokeswoman Emily Shanklin wrote in an email to Discovery News.
The Falcon 9 rocket due to fly on March 16 will be carrying a Dragon cargo capsule for the International Space Station. The mission is the third of 12 under SpaceX’s $1.6 billion contract with NASA.
The company, based in Hawthorne, Calif., also is working on version of Dragon to fly people.(Feb 24, 2014 05:16 PM ET // by Irene Klotz)