A prototype SpaceX passenger Dragon spaceship will fire its eight SuperDraco thrusters to demonstrate how it can fly astronauts to safety in case of an accident at the launch pad. Image credit: NASA/SpaceX

May 4, 2015 Key test for SpaceX passenger Dragon on tap this week

Sen—Garrett Reisman, a former astronaut who now serves as director of crew operations for SpaceX, has some advice for people wanting to watch the debut test flight of the company’s passenger spaceship: Don’t blink.

The six-second firing of the capsule’s eight SuperDraco thrusters—beefed up versions of the small engines used on SpaceX’s cargo Dragon capsules—will catapult the spaceship almost one mile into the air before parachutes pop out to guide it to a gentle splashdown in the Atlantic Ocean, just east of SpaceX’s Florida launch site.

“I can hold my breath the entire time, probably,” quipped Hans Koenigsmann, a SpaceX vice president.

But the value of the test, slated for just after sunrise on Wednesday, isn’t measured in time. Rather, it is intended to demonstrate a key safety system that gives future passengers a fighting chance of surviving a launch pad accident.

“It’s our first big test on the crew Dragon,” Koenigsmann said. “I’m really stoked. I hope it’s going to be a good show.”

“I think we’re doing something historic here,” added Jon Cowart, the NASA manager who oversees the agency’s partnership with SpaceX.

The last time a U.S. spaceship was outfitted a launch abort system astronauts were flying Apollo capsules to the Moon and living aboard Skylab, the United States’ first space station. NASA thought its space shuttles would be safe enough to skip an escape system. The 1986 Challenger accident shattered that illusion.

“When the shuttle was developed, NASA was very much feeling its oats. We had just gone to the Moon, which everybody said was impossible, and so we designed a spaceship we thought did not need (an escape system.) And we did,” Cowart said.

NASA not only will have an escape system for its Orion deep-space capsule, but is requiring emergency escape systems on the commercial space taxis being developed to ferry crews to and from the International Space Station. The systems also are intended to meet upcoming Federal Aviation Administration guidelines for flying paying passengers in space.

Russia and China—the only other countries that have launched people into space—use escape systems on their spaceships that are similar to NASA’s Mercury and Apollo designs. These feature a solid-fuel rocket mounted in a tower that sits above the capsule. In case of an emergency, the rocket would fire, pulling the capsule a safe distance away from the launch vehicle so it can parachute to safety.

On routine flights, the tower and rocket are jettisoned. A launch escape system has been used just once in an emergency during a human spaceflight. In 1983, a Russian Soyuz rocket caught fire just before liftoff. The crew’s capsule was flown to safety seconds before the booster exploded.

SpaceX will be testing a different design. Instead of using a launch tower and solid-rocket motor to fly a capsule to safety, SpaceX’s Dragon is designed to use its own liquid-fueled thrusters to push itself away from danger.

It’s the same thrusters that are used for in-space maneuvering and potentially for a propulsive landing.

“It basically uses a propellant that you have anyway onboard. That makes it lighter. You also don’t have a separation event, so you don’t have to throw it away every time … it’s integrated into the system. You have redundancy …  Overall, it’s the more sophisticated, modern approach,” Koenigsmann told Sen.

“In my opinion, it’s also the safer approach to launch escape,” he added. “On some rockets, there are times you can’t get out. On this particular vehicle … whatever happens to Falcon 9 (launcher), you will be able to pull out the astronauts and land them safely. In my opinion, this will make it the safest vehicle that you can possibly fly.”

For Wednesday’s test, SpaceX installed a dummy, nicknamed “Buster” as an astronaut stand-in. The capsule is heavily instrumented so engineers can learn how the abort maneuver would impact occupants, a key point of the test.

“At the end of the day, the point is to collect data. We see if we have to make any modifications, or if we can fly again right away,” Koenigsmann said.

SpaceX plans to refly the Dragon capsule used in Wednesday’s test in a second, more dramatic launch abort scenario. That flight, targeted for this summer from Vandenberg Air Force Base in California, will demonstrate Dragon’s ability to fly away when its Falcon 9 launcher is at maximum thrust.

SpaceX plans to follow its second launch abort demonstration with an unmanned orbital test flight of a passenger Dragon capsule in 2016. The first flight with test pilots—probably one NASA astronaut and one SpaceX astronaut—is targeted for 2017.