Earlier this month, SpaceX carried out a successful test of the Crew Dragon's Launch Abort System (LAS), which would carry the capsule to safety in the event of an emergency. This is no doubt a great comfort to future space travelers, but what about the ground crew or if the astronauts aren't inside the capsule when an emergency occurs? To help protect them and speed them away from danger, NASA is testing a 45,000 lb (20,412 kg) MRAP armored vehicle as an evacuation carrier for upcoming manned missions.
A rocket that's about to explode is a terrifying thing. Since a rocket is basically a giant bomb, the best place to be in an emergency is nowhere near it, which is why launch control, even if it's only someone with a battery and a couple of wires, is always located in a heavy bunker or as far away from the launch area as possible. For the ground crew, on the other hand, it's a matter of running like hell for the nearest blockhouse, safety trench, or foxhole before the fireworks kick-in.
This was bad enough when the rockets being sent up were V2s and WAC Corporals, but the beginning of the US manned space program added a new twist. The rockets were getting bigger and bigger, and getting astronauts into their capsules meant having crowd crews on the gantry closer to launch time (and the fully fueled rocket) than was particularly comfortable.
Over the past half century, a number of evacuation systems have been used by NASA. On Alan Shepherd's Mercury Redstone 3 mission a crane and basket was used, and a more elaborate evacuation system was installed on the gantry on the Apollo launch pads. NASA estimated that if the Saturn V exploded, it would be twice as devastating as the Soviet N-1 Moon rocket that blew up on July 3, 1969, or the equivalent a half-kiloton atomic bomb. This would have produced a fireball a quarter of a mile wide and a blast would have killed everything for miles around.
Getting away wasn't an option, so a 200-ft (61-m) slide leading to a rubber-lined room 40 ft (12 m) below the Saturn V launch pad was installed. Behind this was a 6-in (15-cm) steel door, which sealed off a steel, concrete, and sand bunker set on massive springs and furnished with heavily padded, safety-harness-equipped chairs for 20 people and enough food, water, and air to keep them alive and comfortable for 24 hrs while rescuers dug them out.
For the Space Shuttle, NASA adopted a slide-wire basket system, which could carry the astronauts and crew out of the blast zone, where they would be caught by a set of bungee cords sprayed with fire-retardant foam, then bundled into a modified Vietnam-era M113 armored personnel carrier, which would (hopefully) get them to safety.
For the planned Crew Dragon and CST-100 launches expected to begin in 2017 and, eventually, the Space Launch System and Orion, NASA is reviving the Shuttle evacuation plan to carry the evacuees 1,300 ft (396 m), but has decided to upgrade the evacuation vehicle with an ex-Department of Defense Mine Resistant Ambush Protected (MRAP) vehicle. Built for the Iraq War, these vehicles are specially designed to withstand blast damage from IEDs and other threats, but are faster and more responsive than the old M113, with cruising speeds of up to 50 mph (80 km/h).
The idea is that the MRAPs will be standing by at the bottom of the slide wire on launch day and, if anything goes wrong, the astronauts and crew can either shelter inside or, more likely, drive out of the danger zone to a helipad or hospital. The MRAPs have been specially modified by NASA's Ground Systems Development and Operations Program and painted white. Speed is key to surviving a blast, so the the steps for entering the rear of the MRAP are being replaced with a ramp to allow evacuees to run inside instead of climb.
The MRAPs are currently undergoing timing tests at Space Launch Complex 41 at Cape Canaveral Air Force Station, Florida. Involving engineers from Boeing, NASA's Commercial Crew Program, United Launch Alliance, and Special Aerospace Service, the tests are to determine the speed and maneuverability of the vehicles, as well as trialling the primary and secondary evacuation routes. NASA says that so far, the MRAP has proven faster and quieter than expected, but more simulations and analysis will be needed before scheduling a full dress rehearsal.
"Knowing how long it takes to get a person from the pad to where it will be safe is critical in our risk reduction for the crew," says Steve Payne of Commercial Crew, a former shuttle test director. "You can draw lines on a map all you want, but until you get out and run the course in real-life conditions, you don't know. You think you know, but you don't know."
The video below shows the rollout of the MRAP at Cape CanaveralSource: