totm nov 2023 SpaceX Discussion Thread

[kerbiloid]

Spoiler

Also training the test crew

Spoiler

 

 

[ThatGuyWithALongUsername]

4 hours ago, tater said:

He was asked about payload, and the questioner said 150t to LEO, and he was not corrected.

Yeah, this is still the max capability of the rocket (kind of?). It was clarified in this tweet in July:

and I believe mentioned at the presentation last month in a graphic or something.

 

I'm much more interested in the "elevator" thing to get cargo to the surface? How does that work? I'm a bit confused? Also, this is a new, 4th "cargo to surface" variant, is it not?

(Source: dgmckenzie on NSF forum, taken from presentation)

Edited October 20, 2019 by ThatGuyWithALongUsername

[k00b]

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150mT for reference payload compared to other rockets

instead; how about the rocket that people are talking about ?

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100mT to 125mT for true useful load to useful orbit

oh right; 100mT is much less then 150mT... that's very "true"

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About double in fully expendable config, which is hopefully never

maybe it would be helpful to try focus more on the reusable configs and then not get the numbers 33% out ?

[CatastrophicFailure]

6 hours ago, tater said:

 

Thought that was Nathan Fillion for a split second. Now that would be an amusing presentation... 

1 hour ago, ThatGuyWithALongUsername said:

I'm much more interested in the "elevator" thing to get cargo to the surface? How does that work? I'm a bit confused? Also, this is a new, 4th "cargo to surface" variant, is it not?

Looks brilliantly simple, actually. Run tracks down the dorsal surface-no third fin, no problem-stainless, of course, so no TPS needed either. Then the aft dorsal door becomes the elevator platform and the big rover just drives on. Dunno if it would work in earth grabbity, but seems quite plausible for the Moon, maybe Mars. 

[tater]

50 minutes ago, k00b said:

instead; how about the rocket that people are talking about ?

oh right; 100mT is much less then 150mT... that's very "true"

maybe it would be helpful to try focus more on the reusable configs and then not get the numbers 33% out ?

I was trying to figure this out back when that tweet was made. I can't figure out the 100-125t vs 150 if all are fully resusable, and why the 150t is reference vs the lower mass to LEO.

I guess that the propellant reserves for deorbit and landing must be 25+ tons, so you'd not include them to compare with other rockets that don't reuse S2?

[Wjolcz]

57 minutes ago, CatastrophicFailure said:

Run tracks down the dorsal surface

+They could add steel lines to the outside corners of the platform. Not sure how that would mess with the CoM.

[magnemoe]

4 hours ago, Terwin said:

There were also graphics early on that specifically said 150t as well as multiple statements about 150t to orbit, then refuel so you can take the same 150t to moon/mars

Note that starship has the option to burn itself dry, for Moon and Mars this is not an major issue as you need refueling anyway. 
Also landing the superheavy on an ship after an suborbital trajectory. 
This is not an standard mission profile and would only be used for an +100 ton non fuel payload who can not be split up and still fit into an starship cargo bay. 
An nuclear reactor is the obvious one here. 

1 hour ago, Wjolcz said:

+They could add steel lines to the outside corners of the platform. Not sure how that would mess with the CoM.

An pretty lightweight structure. the rails is just to stabilize the platform 
And no I would not use the door as an elevator, yes it save weight but its complex. Now if you are supplying an large base you have astronauts who can fix issues making it way less of an problem. 

[k00b]

2 hours ago, tater said:

I was trying to figure this out back when that tweet was made. I can't figure out the 100-125t vs 150 if all are fully resusable, and why the 150t is reference vs the lower mass to LEO.

I guess that the propellant reserves for deorbit and landing must be 25+ tons, so you'd not include them to compare with other rockets that don't reuse S2?

i dunno, but it liquided me off because it sounds very much like "marketing spiel" and people who buildspace ships shouldn't be spieling.

i bet you are right and they referenced the 150mT as absolute max, as you say; by way of "not infact being able to reclaim pieces due to not having the required propellant", ...and then all the nonsense is to "save face" (because it's embarrassing being 33% out and getting called out by morons like myself.).

the "comparing with other rockets" is complete nonsense though; they should have come out and said "our guys shouldn't have been telling you that" it can actually transit payloads of [X]mT.

[GearsNSuch]

4 hours ago, ThatGuyWithALongUsername said:

I'm much more interested in the "elevator" thing to get cargo to the surface? How does that work? I'm a bit confused? Also, this is a new, 4th "cargo to surface" variant, is it not?

(Source: dgmckenzie on NSF forum, taken from presentation)

Ooh, I like that retro-film look. Classy. 
 

The KSP thing to do would be to jettison the rovers out of the bay with an explosive decoupler and let ‘em fall to the surface.

Edited October 20, 2019 by GearsNSuch

[ThatGuyWithALongUsername]

12 minutes ago, GearsNSuch said:

Ooh, I like that retro-film look. Classy. 
 

The KSP thing to do would be to jettison the rovers out of the bay with an explosive decoupler and let ‘em fall to the surface.

I think that's just a result of taking a picture of a preojector creen, and the render is actually just like the others. But I have to agree... it looks really cool this way. Now I want a higher-res one done like this on purpose! C'mon, SpaceX!

 

...and yeah, that would be he KSP way, wouldn't it

[tater]

2 hours ago, k00b said:

i dunno, but it liquided me off because it sounds very much like "marketing spiel" and people who buildspace ships shouldn't be spieling.

i bet you are right and they referenced the 150mT as absolute max, as you say; by way of "not infact being able to reclaim pieces due to not having the required propellant", ...and then all the nonsense is to "save face" (because it's embarrassing being 33% out and getting called out by morons like myself.).

the "comparing with other rockets" is complete nonsense though; they should have come out and said "our guys shouldn't have been telling you that" it can actually transit payloads of [X]mT.

The guy that wrote the flightclub app---which accurately projects launches so that photographers can point a camera where is says, and they get the shot, including Falcon9 booster return burns, etc, very accurately---simulated Starship/Superheavy given the data we have so far (SS wet and dry mass, total stack mass, Raptor thrust and I_sp) and he gets 150t to LEO, with full reuse (though he said his code has the terminal velocity of SS sideways at ~99m/s instead of the 70-whatever SpaceX shows, but his code is missing some aero effects).

So I'm unsure what the deal is, we'll have to await clarification. The Elon info implies 150t, the lower amount might also be a more realistic limit to what you can put inside the cargo volume mass wise. Starlinks are pretty densely packed, for example. So 150t might be if it carried nothing, and got to LEO with just residual props---150t, plus landing reserve, for example, a useful figure for refilling ops.

[sh1pman]

5 hours ago, tater said:

So 150t might be if it carried nothing, and got to LEO with just residual props---150t, plus landing reserve, for example, a useful figure for refilling ops.

How much fuel does it need to reserve for landing? If it’s 25t or so, then a Mars-bound Starship can probably lift up to 175t and then refill both main and header tanks.

[RealKerbal3x]

9 hours ago, GearsNSuch said:

 

The KSP thing to do would be to jettison the rovers out of the bay with an explosive decoupler and let ‘em fall to the surface.

Don't forget the Sepratrons, to properly get them clear of the bay

[Wjolcz]

Even if the total payload to LEO is 100mT + full reuse then it's an amazing achievement. Even 25mT is good as long as it doesn't end up "refurbished" after each flight like the shuttle did.

[sevenperforce]

4 hours ago, RealKerbal3x said:

Don't forget the Sepratrons, to properly get them clear of the bay

One pair of sepratrons to boost out of the bay; one pair to cancel horizontal velocity, and some cubic octagonal struts for sacrificial lithobraking.

[kerbiloid]

1 hour ago, sevenperforce said:

One pair of sepratrons to boost out of the bay; one pair to cancel horizontal velocity, and some cubic octagonal struts for sacrificial lithobraking.

The octotruss can be replaced with a small decoupler. One part less if properly balance it to hit the ground at correct orientation.

Edited October 21, 2019 by kerbiloid

[Technical Ben]

Just drop a forklift on the first landing. You ever seen the self stowing forklifts on the back of trucks? They use their own lifts to deploy, then use the lift to get the rest of the "cargo".

[sevenperforce]

On 10/19/2019 at 5:14 AM, Spacescifi said:

Just about anything is possible with imagination, and life imitates art and art imitates life. The following illustrates that.

 

You know, I was looking at this over on a thread by @Spacescifi, and I was reminded of the parallels we all like to draw between Tony Stark and Elon Musk. I was also reminded of the various EVA designs that have been proposed over the years, and the most recent one unveiled for Artemis.

Also remember this hideous (but surprisingly mobile) one:

Spoiler

The Artemis suit has a soft exterior with hard internal joints to preserve mobility. What if SpaceX used its existing IVA suit and went with a hard exterior, like the Iron Man suit? The Iron Man suit built by Adam Savage is 3D printed from titanium, is literally bulletproof, and is light enough to walk around in. If SpaceX astronauts on the moon or Mars could don a plate-armor overwrap, it would prevent ballooning of their IVA suit and guarantee joint mobility.

Range of motion is a problem in soft suits because of dynamic volume change. When a soft suit is pressurized, the pressure pushes all joints to the "open" position; any motion within those joints will decrease the total volume in the suit, which increases internal pressure (PV=nRT). Thus, every single motion is essentially compressing a piston, making any activity physically exhausting. Hard suits and hybrid suits have bearings and couplings that allow the joint to change shape without changing total volume.

With plate-armor overwrap, however, the IVA suit would be unable to expand as far as it ordinarily would in a capsule depressurization event. The armor itself would not need to be airtight, of course; it merely provides mechanical backpressure to the IVA suit, as well as providing superior impact, puncture, and radiation protection. The joints would be designed for constant-volume movement. If dynamic volume change remained a challenge, the joints could even be equipped with sensors that would trigger air to be pumped out of the suit when the joint is being compressed and pumped back in when it was extended. In the future, the joints might even have braking mechanisms, to enable a user to "lock" certain joints in position.

[Rakaydos]

As I understand it, all rockets list their payload numbers to something like a 120 km circular orbit at an inclination equal to their launch site.

Nobody actually goes to a 120 km orbit- there's too much drag at that altitude. This isn't just Starship marketing, that's EVERYONE's marketing.

When SpaceX says 100-120 tons to a USEFUL orbit, that's them actually being honest.

 

With that said, if you can get a tanker up quickly enough, even a 120 km orbit can be raised to something more stable, given Starship's refueling capability.

[tater]

150t to a 120km orbit would allow a burn to GTO with over 20t of payload, too.

[tater]

 

[tater]

The delay on the next Starlik launch, and the holes in the SpaceX launch schedule...

I was wondering what was going on, but I bet it has to do with the whole Commercial Crew/Bridenstine kerfluffle. My guess? I think they're gonna hold Starlink launch until they fly MaxQ abort. Just for appearance sake. No "SpaceX" brand launches until they move on their main customer.

[AngrybobH]

6 minutes ago, tater said:

until they move on their main customer.

What's the delay here? The capsule is built, right? Or mostly anyway. Slap that thing on a rocket and press the spacebar launch button. I thought that was the spaceX way of doing things. Why are they so different on this one thing? I understand NASA requires hoops to be jumped through but they could do their own testing as well.

[tater]

Just now, AngrybobH said:

What's the delay here? The capsule is built, right? Or mostly anyway. Slap that thing on a rocket and press the spacebar launch button. I thought that was the spaceX way of doing things. Why are they so different on this one thing? I understand NASA requires hoops to be jumped through but they could do their own testing as well.

They have the capsule at the Cape. They have to first do the ground test (the one they did before), then they do the flight test. I think it's scheduled for November. They also have a CRS early December. Holding off on Starlink means that the next launches are all for NASA.

That's my guess, anyway.

 

[CatastrophicFailure]