5:45pm EST Update: SpaceX counted down toward the first high-altitude launch of its Starship vehicle on Tuesday, but its main engines aborted the attempt at T-1.3 seconds. It is not clear whether there was an issue with one or more of the Raptor engines or if a sensor detected some problem elsewhere in the rocket to automatically trigger the abort.
If this issue can be diagnosed and addressed, SpaceX has a back-up opportunity on Wednesday, during the daylight hours in Texas, to try again. The window runs from 8am CT (14:00 UTC) to 5pm (23:00 UTC). Fortunately, weather appears to be exceptional on Wednesday.
Original post: Today’s the day. Probably.
After multiple ground-based tests of the propellant tanks inside its Starship prototype and firings of the vehicle’s three Raptor engines, SpaceX says the large vehicle may fly on Tuesday from the company’s launch site near Boca Chica Beach in Texas. The earliest the flight may begin is 11am ET (1600 UTC), but more likely it will not occur until sometime during the afternoon hours. Weather conditions are nearly perfect, but there are still myriad technical issues with this new hardware that could prevent a flight today.
This is the first time SpaceX has attempted to fly Starship to a high altitude—the vehicle may fly as high as 12.5km. Previous tests have only gone up to about 150 meters and have not included the flaps, nose cone, and other features needed to control the vehicle’s flight in the thin upper atmosphere.
Because of the new flight profile, a lot could go wrong with the test. After ascending to its peak altitude, the vehicle will perform a flip maneuver to reorient itself for a return to Earth at a 70° angle of attack. Then, near the surface, Starship’s three engines will re-ignite, and the vehicle will land vertically, under powered flight.
SpaceX founder and chief engineer Elon Musk has estimated that there is about a one-in-three chance of the vehicle landing safely. In talking to several current and former employees, this estimate seems about right. There are many unknowns with regard to this flight, and in lieu of testing them with further simulations, the company has chosen to just go ahead and fly.
It can afford to do this because the program is rich in hardware and following an iterative design method. The vehicle on the pad in South Texas is “Serial Number 8,” or SN8. This Starship prototype is the same size and shape of the final vehicle, although the company is still tinkering with the landing legs, flaps, and much, much more. SpaceX already has nearly completed construction of SN9; SN10 is perhaps a couple of weeks behind, and parts of several other vehicles are in the works. With each vehicle, the welds get smoother and the manufacturing processes more precise. Lessons learned from SN8 will be incorporated into future vehicles.
To reach orbit, Starship will need to be launched on a Super Heavy rocket. SpaceX has begun constructing a prototype version of this rocket in South Texas as well. If SN8 or SN9 flies successfully, it is possible that SpaceX may be able to attempt an orbital flight late next year with both the rocket and Starship upper stage. Within a couple of years, Starship may begin launching very large payloads into space, with human flights potentially following by the mid-2020s.
But that is getting ahead of the game. Today, or later this week, is all about testing the prototype, with its novel Raptor engines, large, stainless steel fuel tanks, flaps, and the complex flight software written to control the large vehicle’s flight through the atmosphere.
Today is about getting our first glimpse into the future of spaceflight.