totm nov 2023 SpaceX Discussion Thread

[darthgently]

5 minutes ago, sevenperforce said:

18 hours ago, CatastrophicFailure said:

On 12/9/2023 at 6:25 PM, SunlitZelkova said:

One blog called it “too big for LEO missions, too small for lunar missions”

So, basically, SLS? 

OOOOOOH that burns like an pad without a deluge.

And smarts like a chunk of concrete at high velocity

[tater]

27 minutes ago, sevenperforce said:

I really have no idea what the correct ordering is in terms of payload capability.

Yeah. The issue is that the difference between some of them is likely small for the 2 core configs, and the target orbit as well. F9 now does 18.6t to LEO with ASDS recovery. Expended, SpaceX claims 22.8t. Wiki says FH with all 3 recovered is ~30t. Presumably a 2 core variant would be somewhere in between for 18.6t and 30t for 2 core recovery operations. As usual, the payloads are sort of volume limited (the 18.6t Starlink v2minis are probably the densest payload possible since they stack tightly), so this is very likely then more driven by target orbit since the added payload will be propellant residuals in S2.

Edited December 11, 2023 by tater

[darthgently]

6 minutes ago, tater said:

As usual, the payloads are sort of volume limited

Factor 3D printed Procedural Fairings ™ into the eqn and the possibilities are endless

[tater]

2 minutes ago, darthgently said:

Factor 3D printed Procedural Fairings ™ into the eqn and the possibilities are endless

Well, there's actually supposed to be a long fairing at some point per the USSF contract, which will increase actual payload mass by a few tons assuming dense like starlink.

[sevenperforce]

1 hour ago, tater said:

Yeah. The issue is that the difference between some of them is likely small for the 2 core configs, and the target orbit as well. F9 now does 18.6t to LEO with ASDS recovery. Expended, SpaceX claims 22.8t. Wiki says FH with all 3 recovered is ~30t. Presumably a 2 core variant would be somewhere in between for 18.6t and 30t for 2 core recovery operations. As usual, the payloads are sort of volume limited (the 18.6t Starlink v2minis are probably the densest payload possible since they stack tightly), so this is very likely then more driven by target orbit since the added payload will be propellant residuals in S2.

I went and glanced through the last couple years of launches to try and get some benchmarks for the largest launches to given destinations.

• Falcon Heavy
  • All Cores Expended
    • ViaSat-3, 6.722 tonnes to GEO (5/1/2023)
  • Center Expended, Boosters RTLS
    • Psyche, 2.608 tonnes to heliocentric orbit (8/4/2022)
    • Echostar-24 (Jupiter-2), 9.2 tonnes to GTO (7/29/2023)
    • USSF-67, 3.75 tonnes to GEO (1/15/2023)
  • Center ASDS, Boosters RTLS
    • ArabSat-6A, 6.465 tonnes to supersynch GTO at 90,000 km apogee and 23° (4/11/2019)
• Falcon 9
  • Expended
    • Galaxy 31 & 32, 6.6 tonnes to supersynch GTO at 283x58,433 and 24.2° (11/12/2022)
    • Eutelsat 10B, 5.5 tonnes to supersynch GTO at 261x59,831 and 22.8° (11/23/2022)
  • ASDS
    • SES-18 & 19, 7 tonnes to GTO (3/17/2023)
    • Intelsat 40e TEMPO, 5.59 tonnes to GTO (4/7/2023)
    • Inmarsat-6 F2, 5.47 tonnes to supersynch GTO at 387x41,592 and 27° (2/18/2023)
    • Starlink, 18.4 tonnes to LEO (12/7/2023)
    • USA-343 GPS III-06, 4.352 tonnes to MEO (1/18/2023)
    • Galaxy 33 & 34, 7.35 tonnes to subsynch GTO with apogee 19,800 km (10/8/2022)
    • Danuri, 0.679 tonnes to ballistic lunar transfer (8/4/2022)
  • RTLS
    • OneWeb #17, 6 tonnes to LEO (3/9/2023)
    • SARah 1, 4 tonnes to SSO (6/18/2022)
    • Hakuto-R, 1 tonne to ballistic lunar transfer (12/11/2022)
    • EROS-C3, 0.4 tonnes to retrograde LEO (12/30/2022)

I feel like the supersynch launches are particularly helpful because they represent a maximization of the capability of the stage with a given mission profile. May try to math around with this a little.

[magnemoe]

17 hours ago, SunlitZelkova said:

I’m very lucky to live right on the edge of suburbia. If I drive 5 minutes one way I’m in ranch country and 5 minutes the other way there is a supermarket.

So I get good internet to enjoy discussing with everyone on the KSP forum while also having decent enough darkness to see satellites frequently. Like, I’ll often see 5-6 in one night if it’s clear enough.

Notably, I tend to find them easier to spot in the middle of the night/early morning hours, rather than just after sunrise or sunset.

I came to stargazing too late to see Shuttle with ISS, but the one time I did see ISS, there was a Cargo Dragon trailing behind it. The difference between the station and that ship is just incredible.

Also interestingly, the Cargo Dragon was dimmer than most satellites I see. I don’t know if that we because it was near ISS or if the solar panel side was facing me and absorbing light? If anyone knows please share your thoughts 

Here in Norway its to far north for the IIS, but saw it in Chicago, kind of H shaped who helped it stand out far more over something cross shaped like Mir or the Chinese station. This is no slowly twinkling star. 
This was just after sunset, you only see leo satellites then as sun has to reflect off them. 
More common is trails of high flying planes typically middle east to US. After sunset the sun light up the trail, looks like standard vapor trails but you never see them during day

[CatastrophicFailure]

18 hours ago, Cuky said:

Sadly no. Even starlink today I just happened to be outside at the time they were passing above.  The problem I have is that it mostly passes far out of sight and is only visible for few seconds so I don't even try. But now that you asked me I went to check and on December 20th it should pass above just 100-150km north from where I am located and should be visible for around 5 minutes so I might go looking for it if I don't forget

Set an alarm. Download ALL! THE! APPS! Once you’ve seen it you’ll wonder how you ever missed it before, sucker is bright. 

[CatastrophicFailure]

18 hours ago, SunlitZelkova said:

I’m very lucky to live right on the edge of suburbia. If I drive 5 minutes one way I’m in ranch country and 5 minutes the other way there is a supermarket.

Spoiler

 

 

18 hours ago, SunlitZelkova said:

Also interestingly, the Cargo Dragon was dimmer than most satellites I see. I don’t know if that we because it was near ISS or if the solar panel side was facing me and absorbing light? If anyone knows please share your thoughts 

There’s lots of factors that can determine the brightness of any given space thing. Solar panels are actually very reflective (that’s why the ISS is so bright), but the rest of Dragon is also rather reflective being white. Other satellites might have big solar arrays, too, making them more visible. Even some antennas can do that, like the old Iridium satellites that could flare brighter than the ISS, but only for a moment, if the sun hit the antenna just so from where you’re observing. 

[tater]

 

[tater]

Starlink scrubbed as well (they don't like to do launches with Nation Security launches on another pad)

[tater]

 

[mikegarrison]

17 hours ago, CatastrophicFailure said:

Set an alarm. Download ALL! THE! APPS! Once you’ve seen it you’ll wonder how you ever missed it before, sucker is bright. 

Yes, a year or two ago I remember standing outside my house in the cold on the rare clear winter in the Seattle area, waiting for the ISS to pass over. When it did, there was no mistaking it for anything else.

[tater]

7 hours ago, mikegarrison said:

Yes, a year or two ago I remember standing outside my house in the cold on the rare clear winter in the Seattle area, waiting for the ISS to pass over. When it did, there was no mistaking it for anything else.

Yeah, I use this NASA site: https://spotthestation.nasa.gov/ and when the kid were little it was sorta like having advanced notice of a (slow moving) meteor.

 

Also:

 

[Minmus Taster]

1 hour ago, tater said:

Yeah, I use this NASA site: https://spotthestation.nasa.gov/ and when the kid were little it was sorta like having advanced notice of a (slow moving) meteor.

 

Also:

 

Ooooh, maybe a falcon heavy launch for my birthday 

[tater]

Starlink is go for tonight in ~45 min. Guess the claim it was scrubbed because of SF requirements was wrong.

[tater]

<5 min but looks windy

 

abort

[tater]

 

[darthgently]

 

 

[magnemoe]

32 minutes ago, darthgently said:

 

 

Yes but stop trowing away second stages 

[darthgently]

37 minutes ago, magnemoe said:

Yes but stop trowing away second stages 

More DV and some could possibly be left in orbit for possible repurpose.  But given the variety of Starlink orbits they'd be scattered and in degrading low orbits; not useful at all.  Starship is the nearest real solution 

[Nuke]

refueling infrastructure needs to be build up in earth orbit and beyond. only then can full reuse be realized.

[tater]

 

 

[Exoscientist]

 Zack Golden of “CSI Starbase” says Kathy Lueders has confirmed the automatic FTS destroyed both stages, 

 

 Three points: 1, there were small fires in the engine section prior to AFTS; 2, the flame suppression system has no value if AFTS still activates on fires in engines; 3, Raptor no more reliable now than before on relights:

What Happened to Starship SN11? | SpaceX Starship SN11 Test Flight & Explosion Cause Analysis.

 Bob Clark

 

Edited December 14, 2023 by Exoscientist

[Kartoffelkuchen]

5 hours ago, Exoscientist said:

 3, Raptor no more reliable now than before on relights:

Not again.

If your cars fuel pump breaks down and the engine stops working, would you say that the engine is unreliable?
- Yeah, an amateur who doesn't know about the subsystems required to run your engine perhaps would say that.
 

We still don't know with certainty what happened, so let's not start this discussion again, until we get a little more insight.

[Exoscientist]

1 hour ago, Kartoffelkuchen said:

Not again.

If your cars fuel pump breaks down and the engine stops working, would you say that the engine is unreliable?
- Yeah, an amateur who doesn't know about the subsystems required to run your engine perhaps would say that.
 

We still don't know with certainty what happened, so let's not start this discussion again, until we get a little more insight.

 

 Questions about the Raptor reliability will continue to be raised as long as the Starship continues to explode in flight. The FAA aware of the Raptor’s tendency to leak fuel and catch fire in flight listed rectifying this at the top of list of things it wanted SpaceX to correct. 

 

 Note even in the last two shown here, SN10 and SN15, there were engine fires on landing. And we already know what happened to SN11 not shown here. For SN10 the engine fire led to the vehicle exploding a few minutes after landing. For SN15 the fire was extinguished before it caused an explosion. SN15 was called  a “successful” landing test because it did not explode. But that a Raptor still caught fire during this test gives further evidence the Raptor is still not a reliable engine. 

 

  Robert Clark

Edit: by the way, I understand the point you’re making but perhaps it’s not the best example to give in regards to a rocket engine. For rocket engines the turbo pumps are part of the engine. Indeed they have traditionally been regarded as the most finicky part of a rocket engine. So much so that a saying among propulsion engineers is, “Rockets are turbo pump developments with rockets attached.”

Edited December 14, 2023 by Exoscientist