Rocket failure highlights dangers of spaceflight

It was a bad week for commercial space ventures, starting with the explosion of Orbital Sciences Corp's Antares rocket last Tuesday. Three days later, a Virgin Galactic SpaceShipTwo rocket plane broke up during a test flight over the Mojave Desert, killing one pilot and injuring another.

As rocket components corkscrewed through the Virginia sky at NASA's Wallops Island launch facility on the evening of Oc. 28, one could not help but remember the late 1950s and early 1960s when American rockets were blowing up with alarming frequency at Cape Canaveral. Witnessing yet another test failure of an early Atlas rocket that would eventually carry astronauts into orbit, the famed Apollo 13 commander James Lovell remarked: "It looked like a quick way to have a short career."

A bad week for commercial space ventures got worse on Friday (Oct. 31) when a Virgin Galactic SpaceShipTwo rocket plane broke up during a test flight over the Mojave Desert. The copilot was killed, the pilot ejected and is being treated at a local hospital. Virgin Galactic said it was flight testing new rocket fuel for the first time when the accident occurred.

As investigators sift through the wreckage of the Antares failure, much of the focus is on decades-old Russian engines that were purchased by Orbital Sciences and refurbished for this week's flight. The commercial space company had few options for an engine supplier since none are currently being manufactured in the United States.

The 133-foot, unmanned Antares rocket was carrying cargo to the International Space Station. A launch attempt the previous evening was halted when a sailboat turned up in restricted waters just before launch. Orbital Sciences engineers initially said the explosion was likely caused by a catastrophic failure in the first stage main engines. The explosion occurred approximately six seconds after liftoff from the Wallops Island complex on the eastern shore of Virginia.

As dawn broke on Oct. 29, the damage to the NASA launch complex at Wallops Island, Va., was evident following the loss of the Antares rocket.

Earlier Antares flights were powered by a pair of Aerojet main engines based on the Russian engine design. They use RP-1, or kerosene, and liquid oxygen as propellants to generate over 300,000kgs of thrust. A 2013 test of the Antares rocket and three previous flights to the space station went off without a hitch. NASA has said no further launches are planned until the cause of the accident is found and corrected.

As with the American space shuttle programme, which suffered two catastrophic accidents, the law of averages tends to catch up with rocket science and engineering. After a string of successes, complacency becomes the enemy of space operations. Indeed, Orbital Sciences touted its "flight proven" two-stage launch vehicle as "low-risk design."

Orbital Sciences is one of two NASA commercial contractors carrying cargo to the space station. Space Exploration Technologies Corp., or SpaceX, recently returned a fourth cargo ship from the orbiting outpost. Russian and Japanese cargo ships also service the space station. A Russian resupply mission was successfully launched Wednesday, Oct. 29.

The Antares accident will undoubtedly renew concerns about the safety and reliability of commercial space operators. Veteran aerospace analyst John Pike told EE Times in 2011 that commercial contractors simply haven't "blown up enough hardware" and that SpaceX in particular has been "plagued by random success."

In other words, spaceflight remains a dangerous endeavour in which mission-critical launch systems must be continually tested to the breaking point in order to ensure safety and reliability.

That testing requirement will become even more critical when SpaceX and Boeing start ferrying American crews to the space station at the end of the decade.

In the early days of spaceflight, Wernher von Braun and his German rocketeers were famous for their conservative engineering practises on behalf of NASA. Still, many American rockets blew up on the launch pad—some on live television.

- George Leopold
  EE Times