SpaceX’s Crew Dragon astronaut spacecraft has a key launch Saturday — here’s what’s going down

SpaceX and NASA are getting ready for a key test of SpaceX’s Crew Dragon commercial crew spacecraft on Saturday, and this should be the last major milestone that SpaceX has to pass in terms of demonstration missions before actual crew climb aboard the spaceship for a trip to the International Space Station. Starting at 8 AM ET (5 AM PT), a launch window opens during which SpaceX will hopefully perform what’s called an “in-flight abort” test of its Crew Dragon spacecraft and Falcon 9 launch vehicle, to demonstrate how its safety systems would protect astronauts on board in the unlikely event of an unexpected incident during a real crew flight.

The plan for this mission is to launch the Crew Dragon capsule atop a Falcon 9 — in this case, one that’s using a refurbished booster stage previously flown on three prior missions. This will be the Falcon 9’s last flight, however, as the plan includes loss of the rocket this time around instead of a controlled landing. The launch is intentionally being terminated early — just after the rocket achieves its “Max Q” point, or the moment during its flight when it’s under maximum atmospheric stress, at about 84 seconds post-liftoff.

At that point, the rocket will be about 19 kilometres (roughly 62,000 feet) above the surface of the Earth, and about four kilometres (2.5 miles) from its launch pad at Cape Canaveral Air Force Station in Florida. SpaceX has rigged the Dragon spacecraft’s launch escape system to automatically trigger at this point, which will separate the crew spacecraft from the Falcon and propel it away from the rocket very quickly in order to get it to a safe distance to protect any future passengers. After around five minutes past launch, the Dragon will deploy its parachute system, and then at around 10 minutes after it should splash down in the Atlantic Ocean between 3 and 3.5 km (roughly 2 miles) from shore.

After that, crews will recover the Dragon capsule from the ocean, and return it to Cape Canaveral, where SpaceX will study the spacecraft, including human-sized dummies acting as passengers and sensors within to monitor what happened in the cabin during the test. They’ll use this to ideally show that the abort process works as designed and will protect astronauts on board the spacecraft in case of any emergency that results in an early mission termination.

In addition to the in-flight abort system, SpaceX and NASA are also using this mission to prepare for crewed flight in a number of other ways. Today, astronauts Bob Behnken and Doug Hurley, who will crew the first piloted mission hopefully later this year, ran through a dry run of what they would experience in a live mission. They donned space suits and walked the transom that connects the Crew Dragon and Falcon 9 to its launchpad support structure, as NASA Administrator Jim Bridenstine noted on Twitter.

The test will not involve any attempt to recover the rocket, as mentioned, and SpaceX Crew Mission Management Director Benji Reed said during a press conference today that they do anticipate some kind of “ignition” event with the Falcon 9’s second stage, which could possibly be large enough to be seen from the ground, he said. SpaceX crews will be on standby to recover as much as possible from the rocket wreckage, which will be useful to study, and they’ll also be on hand to minimize any potential environmental impact from the test.

This test was originally scheduled for roughly six months ago, but SpaceX’s Crew Dragon capsule intended for the mission was destroyed during an unexpected incident while test firing its engines. SpaceX and NASA investigated that explosion, and are now confident that they understand the cause of that incident, and have taken steps to ensure that a similar problem doesn’t happen again. The Crew Dragon being used now for Saturday’s test was originally intended to be the one used for actually flying astronauts, and another capsule is currently in development to serve that purpose.

SpaceX’s launch window for this test opens at 8 AM ET tomorrow, but spans four hours, and Reed said it could actually extend longer tomorrow if need be. NASA Commercial Crew program manager Kathy Leuders explained today that it’s crucial that not only launch conditions, but also recovery conditions, are optimal for the purposes of this test, so both will play a factor in when exactly they launch. Unlike with launches actually designed to reach a specific orbit, timing doesn’t have to be quite as on the nose, so there’s more flexibility in terms of making the decision to proceed or stand down. SpaceX has backup opportunities on both Sunday and Monday should they be required.

We’ll have a live stream and live coverage of the test starting tomorrow morning, so check back early Saturday. The stream will kick off around 15 minutes prior to the scheduled opening of the launch window, so at around 7:45 AM ET.