Starship test flight 4. I'm finding it difficult to think of how it could have been much better, given what they intended to test.
The quote they use all the time is, "the payload for this flight is data;" the whole purpose is to examine changes made since the last test with a handful of milestones in mind. They're fond of saying that no matter what they try, only excitement is guaranteed. That said, there were two main objectives for this mission.
For the Super Heavy booster, the objective was to return toward Boca Chica and come to a vertical position above the Gulf of Mexico before splashing down into the gulf. For Starship, the objective was to come through reentry with full attitude control, intact, operational, and do the same sort of landing in the Indian Ocean off the NW coast of Australia. If you remember the first tests with prototype ships launching vertically up to altitudes above commercial air traffic, then falling belly first until a few hundred feet above the ground when the ship would ignite its engines, flip from horizontal to vertical and land. That's what was envisioned for the Starship today.
While I have yet to see video perhaps taken by an aircraft in the targeted area, it looks like both objectives were accomplished.
The only obvious issue in the booster was that one of the 33 Raptor engines shutdown within the first few seconds of flight, unlike Test 3. In the last moments before touching the water in the Gulf, another one of the engines appeared to blow up or RUD (Rapid Unscheduled Disassembly), but the booster appeared to come to zero velocity right at the water surface, although we'll have to wait for SpaceX to tell us if it met all their targets.
A lot of people went gaga over the videos from Starship in IFT-3 and today's were far better. First, the spurious rolling motion and consequent movement of the flaps on the ship were gone. Instead we got what looked like a studio picture on a sound stage - except instead of pink lights shining on the heat tiles, it was plasma at 2500 to 3000 degrees.
Plasma pours over the tiles and control flaps of Starship during reentry high over the Indian Ocean. SpaceX screen capture.
That control flap sticking almost vertically in the frame is at the nose of the ship. Both the white glow close to the flap and the orange-ish glow to its right are plasma. This was the view for minutes, very little movement of the flaps was seen.
As the ship moved into denser parts of the atmosphere and started slowing down more dramatically, they switched cameras pointed at the flap, and we could literally see metal melting off the flap and flying away. It ended up looking more battle-scarred than this view.
Visible damage to one of the flaps on the Starship during reentry. SpaceX screen capture.
Amazingly, with chunks of the stainless steel flap melting and breaking off, the ship maintained its position and continued to fly. Within seconds, the flying molten metal made it difficult to impossible to even see this level of details.
Still a screen capture of a SpaceX video, but relayed by Scott Manley on YouTube
Before this week's test flight, Musk said Starship could fail during
reentry with the loss of a single tile in some areas on the vehicle. It
wasn't clear where tiles fell away from Starship on Thursday, but Musk
posted after the test flight that the favorable outcome "speaks to the
incredible resilience of stainless steel at temperature."
With the flaps melting away and showing large holes in them, it's completely reasonable to expect the flap to break off and have Starship lose attitude control. Instead, the control system took the inputs, calculated how to change things to achieve the flip and came to a stop vertically in the Indian Ocean. Before falling over, as it was supposed to.
It's truly some slick engineering. I've come to expect nothing less from this crew.
It's something we've said before, but the next test flight might be rather soon. SpaceX has already test-fired the ship for the next test flight, and the booster could be static fired soon. The FAA might issue a license faster based on the improvements seen in this flight. The mishap investigations were because SpaceX didn't reach their planned destinations. That doesn't apply this time.
"I think we should try to catch the booster with the mechazilla arms
next flight!" Musk posted on X, referring to SpaceX's plan to snare a
hovering booster with catch arms on the launch pad tower.