Wiki Super Heavy/Starship - General Development Discussion

[scaesare]

Yes. It was a joke. The lack of a smiley face reflects my normally dry sense of humor.

Speaking of payloads, it occurs to me that they could take up a 100 ton tank of liquid Nitrogen in the cargo area. Vent that once you've reached apogee, then reenter at the appropriate mass after deploying a payload.

If you're going to reenter with your payload simulator intact, take up a 100 ton tank of seawater. Though it better be filtered for organics if it's taking water from the Gulf and dumping it into the Pacific.

Yeah, I guess they want to have a payload they can jettison in order to simulate more mass on liftoff, but re-enter without it.

There goes my hopes of it being a Cybertruck.... well unless they can figure out how to eject it... we'll see if the steel panels hold up to re-entry as well as they do to a Tommy Gun...

 

[ecarfan]

Look like the S28 restocking is complete. The final half meter went very, very slowly.

 

[JB47394]

Look like the S28 restocking is complete. The final half meter went very, very slowly.

They apparently banged things up the first time. So either they're being careful this time to avoid the same mess, or they changed something and this is the first attempt with the new hardware.

 

[Robertj]

Starship test flight 15 March no 3

https://twitter.com/x/status/1765037578343121372

 

[ecarfan]

Starship test flight 15 March no 3

It is NET March 14. See this thread.

 

[JB47394]

It is NET March 14. See this thread.

He's in New Zealand. The launch time there is 1:30am on March 15.

 

[Buckminster]

https://twitter.com/x/status/1768543877756060148

 

[ecarfan]

Those numbers are mind blowing, but Elon likes to get ahead of himself. V3? Let’s get V1 fully functional (recovery at Stage Zero, reuse, and in-orbit refueling) and then talk about V2. That will surely take a few years. V3 seems like quite a ways off.

To me the really telling number right now is that V1 expendable completely outclasses every rocket ever built and even those in development right now, and it will surely be significantly less expensive in terms of cost of mass to orbit. In expendable mode.

 

[mongo]

Those numbers are mind blowing, but Elon likes to get ahead of himself. V3? Let’s get V1 fully functional (recovery at Stage Zero, reuse, and in-orbit refueling) and then talk about V2. That will surely take a few years. V3 seems like quite a ways off.

To me the really telling number right now is that V1 expendable completely outclasses every rocket ever built and even those in development right now, and it will surely be significantly less expensive in terms of cost of mass to orbit. In expendable mode.

I though IFT-3 was V2: Raptor V2 and electric TVC.
Raptor V3 can go on next ships, then onto the stretch.

 

[JB47394]

Those numbers are mind blowing, but Elon likes to get ahead of himself. V3? Let’s get V1 fully functional (recovery at Stage Zero, reuse, and in-orbit refueling) and then talk about V2. That will surely take a few years. V3 seems like quite a ways off.

I agree, but the difference with Elon is that he's serious about those numbers. Another CEO might put that stuff in play just for some political agenda, or to bump the stock price, etc. I'm quite sure that Elon is serious, and that he's got people working today on figuring out how to achieve those numbers.

I'll observe that an expended flight would only expend the booster. The Starship, plus its 400 tons of whatever, would be on orbit. Sadly, even if it was fully fueled, it only has 4.3 km/s of delta-V. That would get it to Low Moon Orbit, but not the surface of the Moon. So I guess it would be a great choice for a LEO or LMO space station. By the way, the International Space Station masses 400 tons. Packing all of the ISS's capabilities into the Starship might be a challenge.

I wonder if we'll ever see big transfer boosters. Those would be like a Starship booster that is sitting in LEO, fully fueled, waiting to push a Starship with 400 tons of supplies to Mars, but returning to LEO for another push. I guess that's just a space tug on steroids.

 

[scaesare]

I though IFT-3 was V2: Raptor V2 and electric TVC.
Raptor V3 can go on next ships, then onto the stretch.

Yeah... I suspect, based on the approach SX likes to take, as evidenced with F9, that there's room to grow and expand the envelope with many things in the current design... I'd bet adding Raptor V3 would allow them to hit 10K tons thrust with no size change.

The stretch might require tower expansion, assuming the chopstick grab points move...

(And Elon quotes metric tons, right? So... 22 million lbs. of thrust? If so that's three Saturn V's...

 

[scaesare]

I agree, but the difference with Elon is that he's serious about those numbers. Another CEO might put that stuff in play just for some political agenda, or to bump the stock price, etc. I'm quite sure that Elon is serious, and that he's got people working today on figuring out how to achieve those numbers.

Agreed... he tends to quote stuff they have either worked the math and principles through and see no obstacle to achieving, or actually have tested (like Raptor chamber pressures, Plaid 0-60 times, etc...).

It's why when he says the Roadster w/ SpaceX pkg can achieve >1 sec 0-60 times I shake my head in disbelief...

Timelines are his one Achilles heel...

 

[scaesare]

Incidentally... I was thinking last night about the fact that in just about a year, Space has built and flown to destruction, over 100 of the most advanced rocket engines ever built.

In over 100 years of rocketry, no person, corporation, or nation-state has ever built and flown a full-flow staged combustion cycle engine, much less one capable of the the highest chamber pressures ever achieved. Space has flown 117 on Starship alone. We saw a pic of #300 a few months ago.

Their pace continues to astound me.... they want to fly 8 more times this yr... that's another 300+ Raptors, assuming they don't manage to land and resue any.

 

[ecarfan]

I though IFT-3 was V2: Raptor V2 and electric TVC.
Raptor V3 can go on next ships, then onto the stretch.

Thanks, I’m not entirely clear if the IFT-3 vehicle was a V2 or a V1. If it was V2 then I assume that means a V3 is the stretched version?

So I guess it would be a great choice for a LEO or LMO space station. By the way, the International Space Station masses 400 tons. Packing all of the ISS's capabilities into the Starship might be a challenge.

Well, I am pretty sure that Roscosmos won’t be a part of the ISS replacement station, so that will help with the space requirements. But it seems not that difficult to have two Starships connected by a docking port (or two?) create a new station that will have amazing capabilities.

I wonder if we'll ever see big transfer boosters. Those would be like a Starship booster that is sitting in LEO, fully fueled, waiting to push a Starship with 400 tons of supplies to Mars, but returning to LEO for another push. I guess that's just a space tug on steroids.

That’s an interesting idea. So such a booster, after accelerating a ship towards Mars, would then do a boost back burn to LEO and wait to be refueled? I wonder if SpaceX has thought about that.

 

[Electroman]

Before getting to higher payload capacities, they need to demonstrate landing and in-orbit refueling.

No word yet on how that went in IFT-3

 

[JB47394]

Well, I am pretty sure that Roscosmos won’t be a part of the ISS replacement station, so that will help with the space requirements.

If habitable space stations have any purpose other than pure science, then private companies will set them up. They'll then have a function to determine their form.

That’s an interesting idea. So such a booster, after accelerating a ship towards Mars, would then do a boost back burn to LEO and wait to be refueled? I wonder if SpaceX has thought about that.

Yeah, that's the idea. Has SpaceX thought about that? I'm sure they have. All those futurist types have been banging on about stuff like that for decades. In contrast, I only get speculative about stuff that seems achievable with capabilities I've seen - or slightly beyond.

No word yet on how that went in IFT-3

I just posted a link to a NASA page where they said that SpaceX completed the operation and are reviewing the data. I don't actually know if "completed" means they completed the terms of the contract, or if they just did something on orbit, and that the data about that something needs to be reviewed.

 

[ecarfan]

Love Eric Berger’s perspective: After Thursday’s flight, Starship is already the most revolutionary rocket ever built

He marvels at the views we were treated to of the plasma heating on reentry. He marvels that in just the third test flight:

Starship this week did what every rocket in history this side of the Falcon 9, Falcon Heavy, and Space Shuttle has done before: achieved a nominal orbital insertion and lost its first and second stages.

And then he shifts his focus to costs:

Because of a relentless focus on costs and cheap building materials, such as stainless steel, SpaceX can likely build and launch a fully expendable version of Starship for about $100 million. Most of that money is in the booster, with its 33 engines. So once Super Heavy becomes reusable, you can probably cut manufacturing costs down to about $30 million per launch. This means that, within a year or so, SpaceX will have a rocket that costs about $30 million and lifts 100 to 150 metric tons to low-Earth orbit.

Bluntly, this is absurd.

Yes, it is completely crazy to think that such a cost reduction is going to be achieved very soon. Factor in full reusability in a few years and the launch costs decreases by maybe $10 million?

Love these comparisons:

For fun, we could compare that to some existing rockets. NASA's Space Launch System, for example, can lift up to 95 tons to low-Earth orbit. That's nearly as much as Starship. But it costs $2.2 billion per launch, plus additional ground systems fees. So it's almost a factor of 100 times more expensive for less throw weight. Also, the SLS rocket can fly once per year at most.

Then there's the European Space Agency's Vega rocket. Its costs are roughly on par with a Starship that has a reusable first stage. For $37 million, with Vega, you get about 1.5 metric tons to low-Earth orbit. Again, that's a factor of 100 times less payload than Starship.

And then he emphasizes the other key difference of Starship; the fact that SpaceX can churn out vehicles, and the engines that power them, at an unprecedented rate.

The future of space exploration is happening in real time, right now at SpaceX, and every other aerospace organization is way behind.

 

[JB47394]

Factor in full reusability in a few years and the launch costs decreases by maybe $10 million?

$30 million to loft 100-150 tons is $330-220/kg, and $10 million is $110-73/kg.

For comparison, some numbers from Wikipedia:

Launch Vehicle	Payload cost per kg
Vanguard	$1,000,000
Space Shuttle	$54,500
Electron	$19,039
Ariane 5G	$9,167
Long March 3B	$4,412
Proton	$4,320
Falcon 9	$2,720
Falcon Heavy	$1,500

So if Starship charged Falcon 9 rates for a 100-150 ton payload, that would be a $272-408 million launch fee, providing a pretty good profit margin.

The future of spaceflight is going to depend on how SpaceX structures Starship's launch fees. Well, that, and how long it will take the Chinese to duplicate it.

 

[Ben W]

I'll observe that an expended flight would only expend the booster. The Starship, plus its 400 tons of whatever, would be on orbit. Sadly, even if it was fully fueled, it only has 4.3 km/s of delta-V. That would get it to Low Moon Orbit, but not the surface of the Moon. So I guess it would be a great choice for a LEO or LMO space station. By the way, the International Space Station masses 400 tons. Packing all of the ISS's capabilities into the Starship might be a challenge.

Interestingly, LEO to GEO requires about 3.9 km/s of delta-V, and GEO to the moon's surface also requires about 3.9 km/s of delta-V. So if there were refueling depots/stops in both LEO and GEO, this could allow a single Starship to get 400 tons to the moon. Or having an intermediate depot in an eccentric elliptical orbit (plus a LEO depot) might also do the trick more efficiently.

I wonder if we'll ever see big transfer boosters. Those would be like a Starship booster that is sitting in LEO, fully fueled, waiting to push a Starship with 400 tons of supplies to Mars, but returning to LEO for another push. I guess that's just a space tug on steroids.

I remember hearing that the Falcon 9 booster could (just barely) make it into LEO as a single stage. If the same is true of the Super Heavy booster, and it could reach a refueling depot, then this would make an excellent way to explore the outer solar system. My guess is that a fully-fueled Super Heavy stack in LEO could easily boost itself to low Lunar orbit, partially refuel the booster from Starship, then have Starship descend, land and drop 400T cargo, relaunch, reattach, and boost the whole stack back to LEO. (Or just transfer fuel and otherwise travel independently.) Maybe the stretched V3 configuration could accomplish this?

 

[JB47394]

So if there were refueling depots/stops in both LEO and GEO, this could allow a single Starship to get 400 tons to the moon. Or having an intermediate depot in an eccentric elliptical orbit (plus a LEO depot) might also do the trick more efficiently.

Unfortunately, the GEO tank farm would be untenable. You're going to spend propellant to get your tanker there, and then back again for another trip. That means you're using propellant to push the tanker and its return propellant around. The amount of propellant coming from the Earth explodes in mass. You'd be killing yourself just trying to get one load of propellant to the GEO tank farm.

My guess is that a fully-fueled Super Heavy stack in LEO could easily boost itself to low Lunar orbit, partially refuel the booster from Starship, then have Starship descend, land and drop 400T cargo, relaunch, reattach, and boost the whole stack back to LEO. (Or just transfer fuel and otherwise travel independently.)

I've been trying to wrap my head around an optimal way of doing round trips, but it's just so ugly without an LMO tank farm supported by a Moon base. A fully-tanked stack requires 4,600 tons of propellants. Optimistically assuming that a Starship tanker could get 200 tons to LEO, that would mean twenty-three launches to get a LEO stack loaded.

So the goal is to get that LMO tank farm going. Then all you have to do is put a vehicle in LEO that can move cargo to the LMO tank farm. It wouldn't be anything that exists today because it could have a single Raptor engine, have crappy structural integrity, and take its time getting to its destination. It would be a pure spaceship. It flies to the LMO tank farm, transfers its cargo, tanks, and returns to LEO. Then it has to be tanked from Earth, but it only needs 4 km/s of delta-V. Crew would be moved in a different vehicle with different performance requirements.

Once the cargo is at the LMO tank farm, a separate vehicle that cycles between LMO and the Moon's surface takes it down. It goes down, unloads its cargo, tanks at the surface, takes on propellant cargo, goes back to LMO and transfers propellant to the LMO tank farm. That vehicle would be custom designed for its mission as well. It would have a landing capability, and be structurally strong enough for the rigors of Moon operations.

So I guess the bottom line here is that Starship is designed specifically for Earth operations, and we're going to need new vehicles for Moon operations. But that's a ways off in the future.