Why Did the Antares Rocket Explode?

The much-anticipated launch of Orbital Sciences' Antares rocket, on a cargo resupply mission to the International Space Station, ended in disappointment last night when the unmanned rocket disastrously exploded after about 10 seconds of flight.

The Antares explosion: RT/ YouTube.

Fortunately, nobody was injured during the explosion, but damage to the Wallops Flight Facility is severe—not to mention the blow of losing the mission's payload of scientific equipment and crew supplies.

The damage to the facility and Orbital's reputation as a safe ISS vehicle will likely take the company out of the ISS resupply game for several years. This will place future US-based missions solely on the shoulders of Orbital's competitor SpaceX, a company that—with respect to Orbital's impressive team—has already outpaced the company on a few levels.

Both companies were awarded contracts from NASA in 2008, but SpaceX was much quicker to the take when it came to getting vehicles to the ISS. The company's first cargo resupply mission successfully launched on October 8, 2012, around the same time that Orbital was getting around to running the first major tests of the Antares on the launchpad.

Since then, SpaceX has pulled off four successful resupply missions, with its fifth coming up this December. Last night's launch would have been Orbital's third resupply mission.

The other key difference is the technical approach the two companies took in developing their rockets and capsules, and how that ties into their comparative overall outlook.

Orbital opted to go for already established spacecraft designs, making the controversial decision to dust off a bunch of Soviet NK-33 engines to propel the Antares into low-Earth orbit. These engines were originally intended to power the ill-fated Soviet moon program of the late 1960s/early 1970s, but were stockpiled when those missions were axed.

Orbital refurbished and modified them for 21st century spaceflight—renaming them AJ-26s—but the fact remains that the lynchpin of their propulsion design is a decades-old rocket engine. The AJ-26s were determined to be the cause of another Orbital explosion earlier this year, but whether that makes it more or less likely that they contributed to last night's failure is anyone's guess at this point.

SpaceX's approach, on the other hand, was to reinvent rocket designs—which ties into CEO Elon Musk's larger ambitions to pull off a manned Mars mission.

SpaceX's Falcon family of rockets are slowly evolving into a completely reusable launch system, whereas the Antares family remains totally expendable—both the capsule and rocket burn up in the atmosphere. Musk is also investing in exotic concepts like the Grasshopper rocket, which can take off and land back on a launchpad, as part of his larger vision of a recyclable space ferry.

The Grasshopper in action. SpaceX/ YouTube

The cause of last night's disappointing launch failure is open speculation for the moment, but the effect is pretty clear: Orbital is going to be out of the picture for a while as the company recovers and rebuilds. American resupply missions will be up to SpaceX until another solution can be worked out.

It's a sad time not just for Orbital, but for space enthusiasts in general. But it also serves as a reminder that the last 60-odd years of refining rockets hasn't made spaceflight accident-proof. Despite all our advances, it is still very difficult and impressive to blast a rocket filled with cargo to an orbiting space station. Orbital deserves credit for their successes with the Antares as much as they deserve scrutiny over its unexpected failure last night.