Antares vs. Falcon 9: How the two rockets ferrying NASA's cargo differ
SpaceX's Falcon 9 rocket has already proved itself able to get a cargo payload to the International Space Station. Orbital Sciences' Antares rocket, set for its first test launch Wednesday evening, is a very different animal.
Glistening white and standing 130 feet tall, the second of two commercial rockets NASA is relying on to ferry cargo to the International Space Station is set for its first test flight at 5 p.m. EDT Wednesday.Skip to next paragraph
In Pictures Aboard the International Space Station
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If all goes well, the Antares rocket, built and operated by Orbital Sciences Corp., will join Space Exploration Technologies Corp.'s (SpaceX) Falcon 9 as replacements for the space shuttles that carried cargo to and from the ISS. The Falcon 9 and its Dragon cargo capsule already have completed two formal resupply missions to the station.
"We did come late to this activity," acknowledges Frank Culberston, a former NASA astronaut and now an executive vice president at Orbital Sciences. The company signed on to NASA's Commercial Orbital Transportation Services (COTS) program about 1-1/2 years after the program began, after NASA dropped one of the two initial participants.
"We've been playing catch-up, but we've about caught up. By the end of next year, we should have another four or five cargo missions under our belt," he adds.
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NASA's initial choice of two companies for the COTS program involved aerospace upstarts born within a year of each other. Now, the program has paired a grizzled spaceflight veteran with a precocious tweenager.
Orbital Sciences has been building satellites and building and launching rockets for more than 30 years. SpaceX was founded in 2002.
Their approaches to designing and building their rockets are markedly different.
SpaceX has prided itself on designing and building its hardware in-house, beginning with its two-stage, liquid-fueled Falcon 1 rocket. The Falcon 1, with a single engine in its first stage, had teething problems. First launched in March 2006, the rocket's initial three missions failed to deliver anything to orbit. After a fourth, successful test that put a dummy payload into low-earth orbit, the Falcon 1 went on to loft a Malaysian remote-sensing satellite a year later, only to be retired as SpaceX focused on its workhorse, the Falcon 9.
Nearly 200 feet tall, the Falcon 9 boasts nine main engines and can loft much heavier payloads than its predecessor. Sometime this year, the company plans to test a third rocket, the Falcon Heavy – in effect three Falcon 9s strapped side by side, with the center booster topped with a second stage and a payload. The company bills the Falcon Heavy as the most powerful rocket the US has seen since the Apollo program's Saturn V rocket in the 1960s and '70s.
The company's ultimate quest is to develop reusable rockets, in addition to the reusable capsule it has built to carry cargo and eventually humans. SpaceX is testing a propulsion system that will allow a rocket booster to land vertically.