Today’s IFT (integrated flight test) will have Spacex and NASA at least contemplating doing cartwheels. While it didn’t quite meet all of its stretch goals it came very close and exceeded its main goal by some distance. We will not know how well it actually did because so much data was collected. How successful the in flight propellant transfer performed will have to wait and there is a huge range of possible success and failure point with it. However they actually now have data to analyze a huge step forward.
Recapping:
After some holds and false starts caused by boaters failing to clear the exclusion zone the ground systems preformed right on the checklist timelines and with the upgrades made recently in about half of the time of the other flights. The fire suppression systems and the water deluge system came up on time and at T-3 all 33 engines started their firing and throttle up sequence. Lift off of the 35 story rocket appears to have happened when expected. (Liftoff for Starship will be a bit of a variable as the booster isn’t clamped down at that point and it is when the thrust to weight ratio goes positive that it will start to move so payload and even atmospheric variables will have an effect.) From there the next big goal is the hot staging separation. The idea here is to not lose any momentum so the second stage fires while the first stage is still going but throttling down. Hot staging is not new but when used before it was always with the booster designed throwaway, Super Heavy is designed to be reusable and while this booster was never intended to be recovered the pre-landing maneuvers for it were designed to show that possibility. We can now see how much was learned from the previous flight as the Hot Stage went it appears perfectly. Starship continued towards space and the booster went into its boost back maneuver designed to put it in a trajectory towards its designed landing area. We got some extraordinary visuals of the booster’s return phase and the grid fins worked as designed as did the thruster maneuvering. This thruster maneuvering is something a bit different. Most rockets have dedicated designed rockets or cold gas thrusters, As amiganguli says in his live coverage in Starship IFT-3 is coming!
It seems like the gas thrusters are the next area that needs attention. To my untrained eye, it looked like the ship was rolling more than it should have. The thrusters get their gas from the fuel tanks themselves. The tanks need to vent as cryogenic fuel boils off, and that gas is “reused” to help orient the ship. We should know for sure when the next FAA report is complete.
That is for both Starship and Super Heavy. They actually seem to have performed OK in my view.
But here is the first less than perfect outcome for today, the engines for the landing burn suffered some problems relighting. So instead of a soft landing, splash down was pretty darn hard. Importantly the data links were rock solid all the way down.
Starship continued on to near orbit nominally. Near Orbit because in this testing phase they want to insure that it reenters even if in a failure and in a place that is not going to cause damage, in this case the Indian Ocean. Once the engines cut off and it went into coast phase the sub objectives could be attempted. I don’t know and wont until the after action briefings and reports come out how successful they were or if the “Barbecue Roll” (spinning the ship for thermal equilibrium maintenance) we observed was intentional. The door function and propellant transfer occurred we just don;t know how well. They skipped the engine relight and again we don’t know why yet. However we did get the reentry sequence started with another set of stunning visuals even to the plasma formation. At 65 miles signal was lost from both telemetry systems at the same time.
So lets start with the Biggest take away. Spacex and NASA now have a system that can deploy payloads to at least LEO. For NASA that means Spacex can get the HLS into orbit at least that is a major milestone. For Spacex it means that they now have a system that can deploy the bigger generation of Starlink Satellites with it and recover at least some of the development costs with deploying them. The next biggest product was the amount of data collected. They got a lot of data they have never had before and that will be plugged into the models are will probably lead to a pretty fast turn around for the next flight.
What I expect for the next flight. First the review will be much shorter. The FAA should have very few problems with what happened today. Except for possibly some minor hardware tweaks I imagine Spacex will want to do most of its upgrades in software and the next flight will be more of a validation. I will not be surprised at all if in addition Spacex decides to add a satellite deployment into the flight plan also. Late spring early summer is my expectation.
Thruster maneuvering and engine relight are the current biggest questions. I do not think they are major at this point as we know the engines can be restarted as proven with the landing tests.
All and all an incredibly impressive test flight.