Project SpaceX SuperHeavy

[Max-Q]

Thanks very much

I have more if it would be helpful.

 

[Marijn]

Using Ant=43.1, I got right on target. 43.0 works as well.

 

[BrianJ]

I have more if it would be helpful.

If you have the time to post them, that would be great

Having said that - the scenario you posted works pretty well for me!
I've tried various combinations, running it with different Time Accel. / Wind Effects / Non-spherical gravity / Complex Flight Model, enabled and disabled - still works OK.
With Wind Effects enabled, it comes up ~50m short due to getting blown around below 5km alt. - but that is pretty much expected (you need a calm day for accurate Starship landings in my Orbiter universe ;-)

I notice the Starship sits down pretty hard at touchdown - it shouldn't do that even with ~49T payload+fuel. I'll take a look at that.

Without Wind Effects, my AP handles the reentry and touchdown pretty well. Spot-on, in fact.

Could you open/close the scenario and post the resulting orbiter.log? Maybe some difference in our set-ups?

Many thanks!
Brian

 

[BrianJ]

Using Ant=43.1, I got right on target. 43.0 works as well.

OK, but it should work for the "recommended" parameters 120km alt., ReA 1.5, Ant 45.
If you can post any scenario where the Starship comes up short (preferably starting above 120km alt) and the associated orbiter.log (as per my reply to Max-Q) it might help me see how the AP is failing.
Since I haven't been able to make the AP fail for me yet, I'm still fairly baffled ?
Many thanks,
Brian

 

[Marijn]

Here's a scenario with ant=45 aiming for lz_kauai. It ended up short at least two times for me. The log is included. https://drive.google.com/file/d/1ER4BuTKXKIfrBJqZgpyOAGdfiTMdPoVb/view?usp=sharing

 

[Max-Q]

Here’s my orbiter.log
Unfortunately, the other scenarios were in my quicksave folder… and I can’t find ‘em right now.
Just tried my scenario again, and it made it to the pad!
It does come in short most of the time…

 

[BrianJ]

Thanks so much for your feedback I'll take a look.
I did give the "Flight Test 1" another run, switched over to IMFD Base Approach at 140km during ascent (rather than 150km) and it did land short. Looks like it "digs in" a bit too much sometimes. Anyway, I'll see what I can do. Thanks again.
Cheers,
Brian

 

[Marijn]

I've done quite a bit of reentries in the last two days. When I launch the same scenario and do all the actions very much the same way at the same times, I still seem to get mixed results. Sometimes it works, at others it comes up short or very rarely, it overshoots. Atm, I am using ReA=1.4 as this setting was three times succesful in a row for me now. Maybe that lets it dig in a bit less?

 

[Donamy]

Could you do a later smaller reentry burn, then do another reentry burn like the Falcon 1st stage?

 

[BrianJ]

I've done quite a bit of reentries in the last two days. When I launch the same scenario and do all the actions very much the same way at the same times, I still seem to get mixed results. Sometimes it works, at others it comes up short or very rarely, it overshoots. Atm, I am using ReA=1.4 as this setting was three times succesful in a row for me now. Maybe that lets it dig in a bit less?

Hey, thanks so much for testing
Are you including the IMFD de-orbit burn each time? Or just running a post-burn reentry scenario?
Anyway, the reentry AP should be able to handle small differences in initial conditions at Reentry Interface (120km alt.)
I shall just have to try and make it more robust - somehow. I have a couple of ideas to try out. We'll see how it goes.
I've got kind of sidetracked playing with CAPSTONE mission right now, but will get back to this asap

Could you do a later smaller reentry burn, then do another reentry burn like the Falcon 1st stage

Hi Don
I'm not sure how that would work, but I get your drift. It would of course need more fuel.
I don't think SpaceX are going that route, but I'll bear it in mind.

Cheers,
Brian

 

[Marijn]

Are you including the IMFD de-orbit burn each time? Or just running a post-burn reentry scenario?

At first, mostly pre IMFD de-orbit burn. So I started doubting whether IMFD does things the same way all of the time. But then I did some scenario's starting after the de-orbit burn. Even though all of them resulted in a succesful catch, I noticed the Landing AP was doing a small turnaround, while at other times, with the same scenario without the de-orbit burn, it didn't.

Anyway, no rush, I am having lots of fun as it is now

 

[BrianJ]

At first, mostly pre IMFD de-orbit burn. So I started doubting whether IMFD does things the same way all of the time. But then I did some scenario's starting after the de-orbit burn. Even though all of them resulted in a succesful catch, I noticed the Landing AP was doing a small turnaround, while at other times, with the same scenario without the de-orbit burn, it didn't.

Anyway, no rush, I am having lots of fun as it is now

Thanks for the report. I also was wondering if IMFD does the same thing all the time. But as I said previously, the AP should be able to handle small differences.
Anyway, I'm glad you're having fun with it I shall see if I can improve reliability somehow.
Cheers,
Brian

 

[Marijn]

Hi Brian,

Meanwhile, I've done many more reentries aiming for the tower at BocaChica and I don't have any issues anymore. I am mostly using BaseSyncMFD assisted with BurnTimeMFD now. That seems to work all of the time.

So the reentry AP works great! I don't think it needs any improvements at this time. You did a great job. Can you release it for the Tanker as well? That would allow for some new interesting scenario's.

When you have the time of course. I'll try again with IMFD to see if I can figure out what was going on earlier.

Thanks!

 

[BrianJ]

Hi Marijn,
that is very interesting about BaseSyncMFD + BurnTimeMFD. I wonder what the difference to IMFD Base Approach is?
I think I have finished playing with Capstone and CrewDragonMFD (for the time being!) so I'll take another look at this.
I feel the Starship autopilot should be able to handle some variation in conditions at reentry.
The difficulty for me is finding scenarios where it fails, so I can see what is happening (the autopilot works pretty well for me using IMFD).
I'll try and update the Tanker variant with an autopilot asap.

Many thanks for testing and reports
Brian

 

[Jeremyxxx]

The LC-39A Starship Orbital Launch Tower construction is in slow progress...

https://twitter.com/i/web/status/1507860159523360769

 

[diogom]

The LC-39A Starship Orbital Launch Tower construction is in slow progress...

https://twitter.com/i/web/status/1507860159523360769

The third segment has been installed already, with the fourth expected within a week

https://twitter.com/i/web/status/1542133206211772416

 

[4throck]

So now pad 39A has two pads

 

[Gargantua2024]

So that makes it Pad 39D? Cause I think there's a small launchpad at LC-39 dedicated to smallsat and sounding rocket launches built in 2019 if I'm not mistaken (named Pad 39C)

 

[BrianJ]

The third segment has been installed already, with the fourth expected within a week

https://twitter.com/i/web/status/1542133206211772416

These guys just don't stop. I can't keep up

 

[Sbb1413]

So that makes it Pad 39D? Cause I think there's a small launchpad at LC-39 dedicated to smallsat and sounding rocket launches built in 2019 if I'm not mistaken (named Pad 39C)

Or 39AB if the original pad is redesignated as 39AA.