Bis repetita for Starship. On Tuesday 2 February, the prototype of SpaceX's future rocket was tested again. This was the ninth example of the vehicle (SN9, for Serial Number 9) to be tested in this way. The aim? To perform a high-altitude "jump", execute complex manoeuvres, test a sequence of ignition and extinction of the engines, then return smoothly to terra firma.
In short, the aim was to reproduce the SN8 test, which took place on 9 December, but with the hope of a different outcome. With the SN8, everything went very well, except on landing: a pressure problem in one of the tanks prevented it from having enough thrust to decelerate sufficiently on return. The result: the SN8 hit the ground too quickly, causing its destruction.
One of the engines failed to restart
Unfortunately, SpaceX didn't manage to write a different ending with SN9. Or to be more precise, it did, but not the one the American company had hoped for. Once again, SN9 ended its career in a huge fireball. Except that this time, the problem that caused the prototype's destruction was not a pressure problem, but an engine incident: one of the three used during the test failed to relight.
" During the tilt-landing manoeuvre, one of the Raptor's engines failed to restart, causing the SN9 to land at high speed and suffer a RUD. "SpaceX explains. A RUD, an acronym for Rapid Unscheduled Disassembly, or Rapid Unplanned Disassembly, is an elegant term and a euphemism for saying that it exploded.
For those who followed the flight live on 2 February, which lasted around a quarter of an hour in all, the SN9's fatal outcome could have been anticipated just beforehand by the fact that the prototype was leaning far too far and arriving far too fast at its landing site for it to go well. In these conditions, it was impossible to land smoothly and correctly on its landing gear.
As with SN8, the SN9 test will undoubtedly be remembered for its fiery conclusion. However, it should be noted that all the previous stages clearly went well: the ascent to an altitude of around ten kilometres, the programmed and sequential shutdown of the engines, the flip onto its side and its return to the launch pad.
" The SN9 was propelled during the climb by three Raptor engines, each stopping in sequence before the vehicle reached its apogee. "comments SpaceX. " SN9 successfully made a propulsion transition to the internal manifold tanks, which contain the landing propellant, before reorienting itself for a controlled aerodynamic re-entry and descent. "adds the company.
For SpaceX, the question now is how to overcome the landing hurdle, which is clearly its current weakness with the Starship prototype. The SN10 model will be the next to try its luck. Further tests are expected in 2021. And if all goes well, it's possible that an inaugural Starship flight could take place as early as November. Unless the crashes persist.
By Julien Lausson
Numerama.com
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