Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

Trevor Mahlmann for Ars

This is a big week for SpaceX, which has an important Falcon 9 launch for NASA taking place from Florida and probably a key test flight in Texas as well.

On Wednesday, SpaceX is scheduled to attempt its ninth launch of 2019: a cargo supply mission to the International Space Station. The Dragon spacecraft will ferry about 2.5 metric tons of supplies, science experiments, and equipment to the orbiting laboratory. This will be the 18th supply mission SpaceX has flown for NASA.

With a static fire of the Falcon 9 rocket already complete, liftoff is presently scheduled for 6:24pm ET (22:24 UTC) Wednesday from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida. The weather forecast is not great, however, with a 70 percent chance of "no-go" conditions.This Falcon 9 first stage has flown once before, launching SpaceX's last supply mission to the station, in May. NASA may fly it for a third time later this year.

The Dragon capsule on top of the rocket has also been to space before. SpaceX said this vehicle has previously flown space station supply missions in April 2015 and December 2017, meaning this will be the first time a Dragon has flown three times. By reusing its Dragon vehicles—after a significant amount of refurbishment—SpaceX has been able to turn its Dragon hatchery in California over to production of the Crew Dragon that will carry astronauts rather than cargo to the station.

Hop test

Meanwhile, SpaceX employees have been hard at work in southern Texas working on a prototype "Starship." The company wants to test the ability of the vehicle (nicknamed Starhopper) to take off vertically and land. The next big milestone is a "hop" test that will see an untethered version of the vehicle rise about 20 meters, move horizontally relative to the surface, and then land. Starhopper has not been unleashed before, so we can probably expect some drama with this test flight.

Once completed, Starship will be powered by six Raptor engines and have the capacity to propulsively land and take off from distant worlds, including the Moon and Mars. It will serve as the "upper stage" for a large booster SpaceX is also developing, called Super Heavy. Recently, Musk confirmed that the current design of Super Heavy has 35 Raptor engines.

For the upcoming hop test in Boca Chica, Texas, SpaceX has attached one Raptor engine to the Starship prototype. In preparation, at 10:25pm local time in Texas on July 16 (03:25 UTC July 17), engineers test-fired the Raptor engine attached to Starhopper for five seconds, producing smoke and fire as expected. About four minutes later, however, a secondary fireball briefly engulfed the engine and vehicle.

Although this looked dramatic, the Starship prototype did not sustain significant damage. Accordingly, SpaceX is now working toward performing this much-anticipated hop test sometime this week. If this test is successful, SpaceX may be able to perform higher flights, up to 20km, this fall, founder Elon Musk has said. Ars will be in Boca Chica this week to provide a full report.

Listing image by Trevor Mahlmann for Ars