SpaceX’s Starhopper test vehicle – after several days of delays while waiting for Federal Aviation Administration (FAA) approval – successfully carried out its 150 meter test flight on Tuesday afternoon from Boca Chica, Texas. Monday’s attempt was scrubbed at T-0 due to an issue related to the ignitor system on the SN6 Raptor, moving the next attempt to Tuesday which was successful.



(Lead Image Jack Beyer for NSF)

The Starhopper vehicle is a test-bed for gaining flight experience with SpaceX’s new Raptor engine by performing short hops. The methane-fueled engine is under development to support the launch provider’s upcoming Super Heavy and Starship vehicles.

Construction of Starhopper began in late 2018, with its first Raptor firing occurring during a static fire on April 3rd, 2019.

Two more static fire tests over the coming months eventually set the stage for the first flight of the vehicle. The plan was to perform a short hop to an altitude of around 20 meters.

After an attempt on the previous day was aborted shortly after engine ignition, Starhopper successfully hopped to an altitude of 18 meters on July 25th.

The next milestone of the test campaign was designed to push the envelope even further. While the initial plan was to hop to around 200 meters in altitude, the test was slightly amended to only target 150 meters.

The change was made to help satisfy the needs of the FAA, who are in charge of licensing the test flight.

Until recently, SpaceX was only licensed to operate Starhopper up to 25 meters in altitude. Therefore, the objectives of the higher altitude test were not achievable unless a revised permit was granted.

Initially, the FAA expressed concerns with SpaceX’s proposal for a higher altitude test. A lack of hazard analysis was cited as one particular problem.

Without the required permit, SpaceX was forced to delay the 150 meter hop past the originally scheduled date of August 12th.

However, in recent days, SpaceX was finally able to meet the requirements of the FAA, and the agency eventually issued the permit.

The 150 meter hop used Raptor SN6 – the same engine that performed the 18 meter hop in late July.

During the 18 meter hop, the methane fueled Raptor engine successfully lifted Starhopper off of the launch pad, translated the vehicle slightly, and then landed back on the launch pad.

However, during the bigger hop, Starhopper not only flew significantly higher, but it also landed on a nearby landing zone.

Road closures for the flight began at 2 pm central time with the opening of the primary test window at 4 pm local time.

However, the road and air space closures did extend to midnight – possibly leaving open the option for a hop later in the day had it been required.

When the test was ten minutes out, police sirens activated. The sirens alerted the residents at the nearby Boca Chica Village that it was time to evacuate their homes.

The locals were asked to head outside for the flight, as the shockwave from a potential overpressure event could shatter the windows in their homes.

Once the countdown reached zero, Starhopper’s engine ignited and the vehicle lifted off from the pad.

SpaceX's Starhopper conducts 150 meter test hop under the power of the SN6 Raptor! THAT WAS AMAZING! pic.twitter.com/7exBqW4HeV — Chris B – NSF (@NASASpaceflight) August 27, 2019

Several cold-gas thrusters located near the top of the vehicle then helped to keep the vehicle stable as the Raptor engine propelled the vehicle.

The nitrogen powered thrusters are identical to the ones used by SpaceX to help recover a Falcon 9 first stage.

Drove two days from LA to shoot Starhopper’s 200m hop but road closures seem to indicate a delay to NET August 26. Here’s video of an RCS test today. Worth it. Oh, you’re still here? I’ve just started a Patreon, please consider supporting what I do. ➡️ https://t.co/4SoNYe10lT pic.twitter.com/K0gr9u9B8F — Jack Beyer (@thejackbeyer) August 21, 2019

If SpaceX was unable to execute the hop on Tuesday, Wednesday was designated as backup day according to the posted road closures.

This test flight is currently slated to be the grand finale for Starhopper. With the vehicle landing in one piece, it is set to be converted into a vertical Raptor test stand with flight testing transitioning to the larger Starship prototypes.

Currently, SpaceX has two full-scale prototypes nearing completion which are designated Starship Mk 1 and Starship Mk 2 respectively. The Mk 1 prototype is being built at the Boca Chica launch site while Mk 2 is being constructed in Cocoa, Florida.

Construction of both prototypes is progressing well, with the primary structures of the two vehicles nearing completion.

According to SpaceX CEO Elon Musk, the two major sections of the vehicles (fairing and tanks) will soon be stacked together. From there, technicians will install the control fins, Raptor engines, and landing gear.

One item resembling a control fin – presumably for the Mk 1 vehicle – was already spotted in Boca Chica by NASASpaceflight forum member BocaChicaGal.

The Starship prototypes are also expected to feature three Raptor engines instead of just one like on Starhopper.

Furthermore, the Mk 1 and Mk 2 prototypes are being designed to reach much higher altitudes to push the test envelope further.

While it is not entirely clear when test flights of the new prototype vehicles will begin, Musk recently tweeted that the prototypes were expected to be outfitted with their engines and control surfaces by mid-September. This suggests that the first flight could occur sometime this fall.

The teams in Texas and the Cape are currently racing to determine which is the most effective at building and flying the Starship vehicles. Currently, the Starship Mk 1 prototype is likely the favorite of the two vehicles to take the skies first.

As Mk 1 is being built at the same launch facility used to support Starhopper, much of the infrastructure needed to execute a launch is already in place.

On the other hand, Starship Mk 2 will be launched out of Kennedy Space Center’s Pad 39A. While that launch site is already being used to support SpaceX’s kerosene-fueled Falcon 9 and Falcon Heavy vehicles, it will require modifications to be able to support a methane-fueled rocket-like Starship.

Additionally, SpaceX also plans to install a brand-new launch mount and flame deflector for Starship rather than utilizing the existing Falcon infrastructure at Pad 39A.

While an exact timeline for completing the modifications to the historic pad are not currently known, the work is already well underway.