Going up into a space is dangerous work. But being an astronaut on the ground can be just as lethal if your rocket, you know, blows up.

Rest assured that NASA has an escape option. In December, the agency’s launch site at the Kennedy Space Center in Florida received the first of four heavily-armored veterans of the wars in Iraq and Afghanistan—Mine-Resistant, Ambush-Protected Vehicles, or MRAPs for short.

Their mission: sit on stand-by during launches for NASA’s next manned rockets, in case something goes terribly wrong.

MRAPs were built by the tens of thousands in response to the improvised explosives that have killed and wounded thousands of American troops. Packing four-inch-thick glass and sealed against chemicals and projectiles but driven like ordinary delivery trucks, MRAPs have saved countless lives.

The vehicles are so heavy and bulky, however, it’s become cheaper to simply abandon many of them in Afghanistan rather than ship them home. There’s also little need for the trucks that do make it back. The Pentagon has been looking to retire or unload them—often into the hands of police SWAT teams.

Launching heavy-duty space rockets is another matter. But if astronauts need to escape from a rocket that’s about to go kaboom, a MRAP might be able to keep the crew alive.

To Hell and back

Getting to orbit requires a lot of energy—and the heavier the stuff you want to throw into the sky, the more oomph you need.

Because of this, up to 90 percent of a rocket’s initial mass is just fuel. That’s why even the winged, reusable Space Shuttles threw away their giant fuel tanks and solid-fuel boosters on the way up to space.

The safety of the crew, sitting atop these giant bombs, is one of the key concerns of spaceflight engineers. Fatal accidents involving Space Shuttles—Challenger in 1986, Columbia in 2003—underscored the need for escape plans on the ground, during ascent, in orbit and during re-entry.

The accident-prone Space Shuttle is now retired. Its replacement, the Space Launch System, goes back to the future with an updated version of the 1960’s Apollo-Saturn design. Like the moon rocket, the SLS will be a huge multi-stage missile with a small crew capsule perched atop its nose.

And like its Apollo ancestor, the Orion crew capsule is fitted with a tower of rockets able to yank the spacecraft off and away from its booster if something bad happens on the way up.

NASA’s MRAPs will help out with rescues during the launch phase, before a rocket leaves the ground.

The fuel load aboard a manned rocket is huge—a Saturn V carried 2.4 kilotons of jet fuel, liquid oxygen and liquid hydrogen. The Space Shuttle’s main tank carried nearly 800 tons of propellant with two giant Roman candles packing 550 tons of fuel apiece strapped to its sides.

The Space Launch System, sharing elements of both the Saturn V and the Space Shuttle, may carry nearly three kilotons of fuel in its liquid-fuel core and solid boosters.

Enormous danger lurks on the ground in the minutes before a manned launch. The rocket sits on its pad hooked up to umbilicals carrying fuel, electricity and data. A small ground crew mans the tower gantry until the last few minutes. Everyone on the pad is at risk of a chemical explosion equal to a small tactical nuke.

Just how big of a bang are we talking about? NASA looked at a failed 1965 launch of an Atlas-Centaur vehicle to get an idea.

The resulting study concluded that a Saturn V pad explosion would produce a fireball over 1,400 feet in diameter with a temperature of 2,500 degrees Fahrenheit. There’s a reason why the public viewing area at Kennedy Space Center is more than seven miles away from the launch pads.

Space Shuttle astronauts riding an M-113 during training. NASA photo

Getaway tanks

NASA gave serious thought to the ground-blast problem during the Apollo program. The solution the agency developed was, frankly, bizarre. With enough warning, the astronauts and gantry techs would hop into fast elevators and plummet 30 stories to the ground, then dive into a bunker built into the launch pad.

Inside the “Rubber Room” they would have strap themselves into spring-loaded couches to ride out the explosion. The Rubber Room was provided with enough supplies for a 24-hour stay until NASA could dig the survivors out of the rubble.

Mercifully, this zany escape plan was never put to the test.

The other escape route—the getaway tank—was never called upon, either. In addition to the run for the bunker, NASA installed ziplines and baskets in the tower gantries which would have delivered rattled astronauts to a pair of parked M-113 armored personnel carriers.

The crew was supposed to hop into the tracked vehicles and roar off to safety, protected from the rain of burning fuel, shrapnel and concrete by the M-113s’ top armor. This method was ready to be used right through the Apollo and Shuttle eras, but was finally retired a few years ago after decades on stand-by.

NASA still thinks the getaway tank is a good idea, given those three kilotons of fuel to be loaded aboard the SLS. But with tight budgets, it’s hard to convince the budget hawks to fund a new, custom-built escape method. With the MRAP, a study team headed by NASA’s Ground Systems Development and Operations Program found what they believe is a suitable vehicle for ground escape.

Although weighing 20 tons, the wheeled MRAPs are faster and more commodious than the tanks they’re replacing, and the price is right—the Army donated the machines to NASA for free.

Danny Zeno, a GSDO engineer who led NASA’s search for a new vehicle, is pleased. “This is definitely an upgrade from the Space Shuttle-era M-113 tank design,” he said. “Working across agencies helped us to select the most versatile vehicle possible for NASA’s purpose.”

In their new jobs, these former war-wagons have a long future ahead of them—awaiting a disaster that will hopefully never happen.

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