The Dragon Capsule, a commercial spacecraft designed by SpaceX to ferry U.S. astronauts into orbit by 2017 is set for a major test on Wednesday, when the private space company plans to blast the capsule away from the launch mount at Cape Canaveral on a mile-high demo flight designed to test the craft's ability to protect occupants in the event of a catastrophic rocket failure on the pad.

While the Dragon Capsule won't travel very far in tomorrow's test, the data from it should give engineers the information they need to prove the capsule's emergency safety system can save astronauts from an explosive launch failure.

The test is scheduled for 7 a.m. EDT on Wednesday from Cape Canaveral's Complex 40 launch pad, the same pad used by SpaceX for operational flights of the Falcon 9 rocket.

Tomorrow's test will be the most visible test to date for NASA's commercial crew program at Cape Canaveral, where SpaceX and Boeing plan to launch crews bound for the International Space Station. Last year NASA commissioned both SpaceX and Boeing to develop the Crew Dragon and CST-100 capsules to end the U.S. reliance on Russian and its Soyuz spacecraft to ferry astronauts to and from the International Space Station.  Both companies say they will be ready to begin carrying astronauts into orbit and to the station in 2017.

The test will be relatively short lasting only 107 seconds, with less than six seconds under power from the Dragon capsule's eight SuperCraco rocket thrusters.

"It doesn't last long," said Garrett Reisman, a former astronaut and current director of crew operations at SpaceX. "The boost phase is only a few seconds, and it's pulling almost 5 G's when it's coming off the pad, so it's going to get out of here in a hurry. My advice to you if you go outside to watch it is don't blink."

For astronauts like Reisman, who flew twice in the space shuttle that had no way for astronauts to escape, having the ability to escape a failure is paramount.

"I think, in retrospect, that was kind of obvious," Reisman says. "As an astronaut, having that (escape) ability is huge - absolutely huge."

"We did the best we could with shuttle. When I flew, we had pressure suits, we had parachutes on our back, we had the pole out the side. We had a lot of things that Challenger didn't have, but the situations in which those things could really help you were pretty limited."

"When the shuttle was developed, NASA was very much feeling its oats," said Jon Cowart, a NASA manager assigned to work with SpaceX's Crew Dragon development program. "We had just gone to the moon, which everybody said was impossible. We thought we could design a spaceship that did not need one, and we did."

"As physics and nature will sometimes do, they taught us a lesson that maybe you should not go do that."

NASA learned from its mistakes as well, mandating that both spacecraft along with the agency's Orion capsule include escape rockets to give the astronauts a means of escape if something terrible does happen.

"Having something that can help you, with validated performance and with a requirement to be over 95 percent reliable if it's ever needed, and have that available from the ground all the way up to orbit, that's huge," Reisman says. "As an astronaut, I can't overstate the importance of that."