SpaceX Starship - Integrated Flight Test #2 - Starbase TX - Including Post Launch Dissection

[JB47394]

Page 6-7 had earlier plan:

That's a great document. Here are some quotes without using the forum quoting mechanism. I only searched for references to reentry. I'm sure there are many more interesting details in the document. I also didn't check to see which individual documents these quotes came from (91 uses of "reentry" in the PDF).

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SpaceX also proposes to add an area southwest of Hawaii, uprange of the passive descent ocean landing area, to account for the potential Starship debris field for the second and third launches of Starship that are not configured to survive atmospheric reentry.

When Starship is not configured to survive atmospheric reentry, Starship would tumble as it descends through the atmosphere and break apart at greater than 50 kilometers (km) above ground level (AGL).

Structural debris of both Starship and Super Heavy is made of inert materials, such as steel, carbon composite, silica heat tiles and is not anticipated to affect water quality. For these reasons, after considering the new information, the chance for marine species to be exposed to the residual propellant is still extremely low and therefore discountable, as the 2022 PEA concluded.

Following the Starship breakup, SpaceX would have a vessel in the area of highest likelihood of debris that would identify large debris for salvage.2,3 SpaceX would use the vessel to survey the debris field for approximately of 24 to 48 hours (using visual survey in the day and onboard vessel radar at night) depending on the outcome of the breakup. The initial survey area would be determined based on last known data location point received from the telemetry on the vehicle upon splashdown.

Super Heavy operations are suborbital and are not considered by the FAA to be a reentry vehicle because they have not completed one orbit around the Earth.

Based on modeling, the area beneath the Super Heavy landing location (31 kilometers offshore) that will receive the maximum overpressure (up to 15 psf) as it is landing would be a maximum of 1.28 kilometers in diameter. The maximum overpressure for a Starship reentry is 2.2 psf

SpaceX will provide notice of the launch and reentry schedule not less than 10 business days in advance of any launch, to the extent reasonably practicable.

SpaceX will submit reentry information, where applicable, at least 30 days prior to scheduled reentry or as soon as practicable for contingency reentry

Contradiction in terms? Or at least a hemioxymoron??

The fuel is methane, the oxidizer is oxygen, but they together constitute propellant because oxidized methane is ejected (CO2 and H2O).

 

[ecarfan]

for the second and third launches of Starship that are not configured to survive atmospheric reentry.

But the vehicles have a complete set of TPS tiles and operational flaps, correct? Why is SpaceX not planning to attempt a reentry maneuver?

 

[mongo]

But the vehicles have a complete set of TPS tiles and operational flaps, correct? Why is SpaceX not planning to attempt a reentry maneuver?

That was the plan from April last year.
Given SpaceX has not succeeded in hitting the ocean with a ship at terminal velocity, they may be repeating the flight 1 scenario. Or, the whole plan is changed.

 

[Grendal]

But the vehicles have a complete set of TPS tiles and operational flaps, correct? Why is SpaceX not planning to attempt a reentry maneuver?

I'm pretty sure SpaceX wants to test the TPS and does everything except the flip and landing burn maneuver. I believe they said they intend for it to hit the ocean hard. I believe it was also said that they intend to try for a soft landing into the Gulf for the booster.

 

[Electroman]

I think they had a full load of LOX in order to more fully simulate the mass that Starship would be for a normal flight.

I assume they dumped some LOX to then simulate what the ship would be experiencing at the point it was approaching LEO, and would then belly-flop (mostly empty) back to earth and attempt a landing burn sequence.

I suspect this next flight we'll instead see the next item in line for payload simulator, after big wheel of cheese and Roadster.

If LOX vent is supposed to simulate the jettisoning of payload, then why vent it even before the engines are shutdown? I mean payload is jettisoned after reaching orbit and after the engines are shutdown, but in this flight LOX venting started happening even before the engines were shutdown.

I agree it takes several minutes for the LOX to be vented (as opposed to jettisoning a payload which happens in an instant), but you have over 70 minutes of flight time left after the engines are shutdown, to do that.

 

[mongo]

If LOX vent is supposed to simulate the jettisoning of payload, then why vent it even before the engines are shutdown? I mean payload is jettisoned after reaching orbit and after the engines are shutdown, but in this flight LOX venting started happening even before the engines were shutdown.

I agree it takes several minutes for the LOX to be vented (as opposed to jettisoning a payload which happens in an instant), but you have over 70 minutes of flight time left after the engines are shutdown, to do that.

It wasn't a matter of simulating payload separation, it was getting mass down before reentry.
As to why then: autogenous pressurization, ullage collapse, and settlement. They can't (easily) jettison with engines off.

 

[Electroman]

As to why then: autogenous pressurization, ullage collapse, and settlement. They can't (easily) jettison with engines off.

Ha thank you !! <light bulb comes on>

This is the part I never grasped from all the discussions earlier. Now it makes sense..

I was thinking there was a pump that is forcing and venting the LOX.. but that is not how this works. Thanks !!

 

[scaesare]

It wasn't a matter of simulating payload separation, it was getting mass down before reentry.
As to why then: autogenous pressurization, ullage collapse, and settlement. They can't (easily) jettison with engines off.

What @mongo said....

And I also assume that they'd want the significant events (thruster firing, any maneuvering, etc...) to be done at the target mass and configuration to gather as much data in as close to real (out of this) world scenarios and a "real" payload wouldn't be able to slosh in the tanks... hence dumping the LOX prior to the subsequent descent through the atmosphere which needs that autogenous pressure...