They attempted to relight the booster, but only 1 of the 13 engines they wanted on actually started (2 others almost started but immediately failed). Their hope was to demonstrate in-space relight of the second stage engines, which is obviously a crucial demonstration for HLS and eventually going to the moon, but they never went for it. So far they have never demonstrated Raptor start in a vacuum and microgravity, which is a significantly different challenge to firing on the ground or even during re-entry as was the case for the booster due to propellant slosh and ullage considerations. In fact, we have seen them struggle with these issues in the earlier Starship solo tests, where the engines upon relight would eat backfill helium and eventually switch over to an engine-rich cycle :D. I’m sure they will figure it out but in space Raptor relights are far from the ‘same’ as what they have already done.
I suppose if you want to add “in microgravity” to that list item, then yeah, they haven’t done that part yet. The list item just said “Re-light Starship engines”, which they have indeed done many times in many circumstances. Just not that particular one yet.
They attempted to relight the booster, but only 1 of the 13 engines they wanted on actually started (2 others almost started but immediately failed). Their hope was to demonstrate in-space relight of the second stage engines, which is obviously a crucial demonstration for HLS and eventually going to the moon, but they never went for it. So far they have never demonstrated Raptor start in a vacuum and microgravity, which is a significantly different challenge to firing on the ground or even during re-entry as was the case for the booster due to propellant slosh and ullage considerations. In fact, we have seen them struggle with these issues in the earlier Starship solo tests, where the engines upon relight would eat backfill helium and eventually switch over to an engine-rich cycle :D. I’m sure they will figure it out but in space Raptor relights are far from the ‘same’ as what they have already done.
They shut down and relit many more engines during stage separation and the subsequent boostback burn. Here’s where they relight the middle ring of Raptors.
I suppose if you want to add “in microgravity” to that list item, then yeah, they haven’t done that part yet. The list item just said “Re-light Starship engines”, which they have indeed done many times in many circumstances. Just not that particular one yet.