On Sunday, SpaceX is launching one of its last big flight tests for NASA, one that could ultimately pave the way for the company to fly people to space later this year. For this flight, SpaceX will test out the emergency escape system on its new passenger spacecraft — and will probably destroy a Falcon 9 rocket in the process. Eurasia Diary reports citing Verge.

The vehicle that SpaceX is testing is its new Crew Dragon capsule, a passenger spacecraft the company has been developing for NASA as part of the agency’s Commercial Crew program. Before NASA will let its astronauts fly on SpaceX’s Crew Dragon, the agency wants to know that the vehicle can keep people safe in the unlikely event of an emergency. That’s what this weekend’s test, known as an in-flight abort test, is all about. SpaceX plans to mimic a failed rocket launch and show that its Crew Dragon can survive and protect its precious inhabitants inside. “We want to practice, practice, practice,” Benji Reed, director of crew mission management at SpaceX, said during a press conference on Frida. “We test like we fly, and we want to practice like we fly.”

Embedded in the hull of the Crew Dragon are eight SuperDraco engines, designed to fire if the Falcon 9 rocket carrying the capsule starts to suffer some major failure. The SuperDracos can propel the spacecraft up and away from the decaying rocket. Once the Crew Dragon is at a safe distance, the capsule would then deploy its parachutes and lower itself gently into the Atlantic Ocean. A recovery boat would then meet up with the capsule and rescue the crew inside.

SpaceX has tested out this escape system before, but only when the Crew Dragon was on the ground. The company and NASA want to see this process in action while the capsule is zooming into the sky on top of a rocket. That’s when the system will be needed most if a worst-case scenario happens in the future. So this weekend, SpaceX will launch one of its used Falcon 9 rockets — which has been to space and back three times before — with a Crew Dragon on top. At 84 seconds after launch, when the rocket and capsule are feeling the most stress during flight, the SuperDracos will fire and the rocket’s main engines will cut off. The Crew Dragon will then go through the entire escape routine.

SpaceX definitely expects to lose its Falcon 9 rocket during this test. The vehicle should break apart on the way back down to Earth thanks to the speed it’s going and the weather conditions. As for how it will be destroyed, that’s unclear. But the rocket will be fully fueled, which means some of that propellant might light up. “We expect there to be some sort of ignition and probably a fireball of some kind,” said Reed.

No people will be on board this flight, though SpaceX will have two smart dummies inside the Crew Dragon to gather data about how the maneuver would affect future crew members. Both the dummies and vehicle will be recovered by boat after the test.

paceX’s Falcon 9 is scheduled to take off from Kennedy Space Center in Cape Canaveral Florida on Sunday, during a six-hour launch window between 8AM and 2PM ET. SpaceX will wait to launch until they see good weather at both the launch site and the place in the Atlantic Ocean the Crew Dragon is expected to fall. Having those weather conditions line up may take some time. “Y’all may be waiting for a while, while we’re trying to find the perfect time for us to be able to conduct this test,” Kathy Lueders, the program manager for NASA’s Commercial Crew Program, said during the press conference. SpaceX was originally supposed to launch on Saturday but had to stand down due to bad weather at both locations.

If this test goes well, then the next big flight of the Crew Dragon will have people on board. The date for that highly anticipated trip is still very much an open question. The Crew Dragon that will be used for that test is slated to arrive in Florida by the end of this month, according to SpaceX. And after the in-flight abort, SpaceX and NASA will need to review all the data and do additional paperwork, and SpaceX still has to do some more tests of its parachutes, which it upgraded last year. “We are really human certifying these Dragon spacecraft and Falcon 9,” said Lueders, adding that “making sure we’ve dotted all the “I”s and crossed the “T”s before our crewed demonstration mission is very important.”

SpaceX’s coverage will begin 20 minutes prior to takeoff, while NASA’s coverage is set to begin 15 minutes beforehand. Since liftoff time could change a lot, be sure to check both SpaceX and NASA’s twitter feed for updates.