Copyright 2024 Robert Clark
An approximate $100 per kilo cost has been taken as a cost of space access that will open up the space frontier. For then instead of a price for a private citizen to go to space instead of millions of dollars, it could be priced at a few tens of thousands of dollars. This is in the range of the price of a first-class roundtrip ticket from Los Angeles to Australia. SpaceX now has the capability to offer such a launcher at such a low per kilo rate.
Robert Zubrin has said in an interview that Elon Musk informed him he believes he can build the Starship, i.e., the upper stage of the Superheavy/Starship launcher, for $10 million:
But Zubrin notes what SpaceX is aiming for is reusability. Say a new Starship might cost $10 million to build with a purchase price of $20 million to the customer. Then allowing conservatively 10 reuses SpaceX might only charge $2 million per use. However, he does not mention it here but he is implying the use of this as a launcher independent of the first stage Superheavy. Then you would need a smaller upper stage, a mini-Starship.
Zubrin has discussed use of a mini-Starship, but in the context of a 3rd stage for the Superheavy/Starship. Presumably here though, he is suggesting a smaller launch system consisting of the Starship now as a first stage and a mini-Starship as an upper stage.
An upper stage is commonly 1/4th to 1/3rd the size of the previous stage. So call the cost of the mini-Starship new of, say, $3 million. However, in regards to reusability, SpaceX has found that difficult to implement for an upper stage, particularly in regards to the thermal protection system. Afterthe last test flight IFT-6 for example, Elon Musk has suggested they might have to change to a completely different kind of TPS than the ceramic tiles now used. In contrast though, SpaceX has ampy demonstated with the Falcon 9 booster the first stage is much easier to reuse. So I'll estimate a cost here of a partially reusable Starship/mini-Starship as $5 million.
We'll calculate here that this smaller Starship/mini-Starship launcher will still be a a Saturn V-class expendable launcher at 100+ ton payload capacity to LEO. It comes from this Elon Musk estimate of the dry mass of the Starship as an expendable:
But that is for an upper stage use where it did not have enough engines for liftoff from ground. Assume for 1st stage use it needs 9 engines. Increase the dry mass now to 50 tons for the greater engine mass.
For the mini-Starship, an upper stage commonly is 1/3rd to 1/4th the size of the lower stage, so call it 420 tons propellant mass. As an upper stage it doesn’t need high engine thrust so assume same mass ratio of ~30 to 1 as for Elon’s expendable Starship estimate, giving it a dry mass of 14 tons.
Take Starship exhaust velocity as ground launched as comparable to that of the Superheavy, 3,500 m/s. And take the upper stage’s vacuum exhaust velocity as 3,800 m/s. Then we could get ~120 tons to LEO:
3,500Ln(1 + 1,200/(50 + 434 + 120)) + 3,800Ln(1 + 420/(14 + 120)) = 9,200 m/s, sufficient for launch to LEO.
This a price of only $5 million launch cost for a Saturn V-class launcher as partially reusable. If we make the landing downrange we lose only ~20% off the expendable payload judging by the Falcon 9 example, so still ~100 tons to LEO as partially reusable. That amounts to radical reduction in launch cost down to only ~$50 per kilo. This means that rather than a price to orbit for a passenger being millions of dollars as it is now, it could be in the tens of thousands of dollars range. As noted by Zubrin in that SpaceWatch.Global interview this is in the range of a first-class round trip tocket from Los Angeles to Australia.
Those price estimates though are based on a $10 million cost of the Starship. But that undoubtedly is for high production rates.
So we'll use an estimate based on the current production cost for Superheavy/Starship at about $90 million, with about 30%, $27 million, for Starship:
STARSHIP COST ANALYSIS
OVERVIEW
Note: This is Payload's current estimate and not based on access to any internal Space data or proprietary information.
Current Estimated Starship & Booster Full Stack Cost (S in thousands)
39 Raptor Engines 39,000
Labor. 35,000
Structure, plumbing, tiles, parts 13,000
Avionics 3,000
Total 90,000
*Payload costs estimates are based on a post-R&D 1-2 year forward-looking model. This is an educated best estimate and not based on Space internal data. Further cost reductions are expected in the long-run. $90M cost: Payload estimates it costs $90M to manufacture a fully integrated Starship based on a post-R&D/test production phase near-term model. The go-forward cost does not factor in the near $5B SpaceX has spent on R&D to date.
~70% of costs accrue to Super Heavy and ~30% to Starship upper stage.
Future Starship (upper stage) cost reductions: As Starfactory comes online and Raptor production is refined, Space aims to reduce costs even further. A focus on Starship's upper stage: When SpaceX achieves full reusability, production of Starship second stage vehicles will be an order of magnitude higher than booster production.
• The company plans to eventually build multiple second stage Starships per week and reduce
Raptor engine's production cost to $250K a pop. If successful, the long-term cost to mass produce second-stage Starships could drop to $10M to $15M a vehicle. However, for purposes of this report, we will analyze costs as they are today.
Raptor 2 engines ($39M) Payload estimates each Raptor 2 engine costs ~$1M to build. The 39 engines-which include three additional upper-stage engines that will be added in the future-are by far the biggest Starship cost, adding $39M to total cost. SIM per Raptor 2 engine is half as expensive as its $2M+ Raptor 1 predecessor. 20 SpaceX hopes to eventually bring the cost per engine down to ~$250K.
Payload Research
18. Elon Musk on X 19. Space 20.Elon Musk on X 21. Elon Musk on X
https://docsend.com/view/fi9wuazzeex57iig
Say, for a mini-Starship upper stage its cost would be a 3rd of the $27 million current production cost of the Starship as new, so $9 million. So the full vehicle production cost at $36 million as new. So a Saturn V-class launcher capable of 100+ tons to LEO at ca. $36 million price new. Note this is about half that of the price of the Falcon 9 but at 5 times the payload capability. This is a cut in price per kilo by a factor of 10 down to $300 per kilo from $3,000 per kilo.
Note again though with SpaceX amply demonstrating practicality of first stage reusability we can do better than this still. Say the Starship now as first stage could be reused 10 times cutting its cost to, say, $2.7 million per launch, for the total partial reuse cost of $11.7 million per launch. But this is the price to SpaceX. Double this for a price to the customer of ~$23 million as partially reusable. As before landing downrange for the booster would still allow ~100 ton payload to LEO, for a price per kilo of $230 per kilo.
This may still allow passenger tickets to orbit at say the hundreds of thouasands range depending on how many passengers could be carried in a passenger cabin. Note this is price range charged by Virgin Galactic and Blue Origin on New Shepard just going to suborbital space. Most importantly, large numbers of launches carrying private passengers to orbit of wealthier customers at the price point doable now will increase the production numbers for the Starship thus enabling the lower price point to be reached.
Launch costs for manned Moon or Mars flights at only ~$20 million per launch.
This is a Saturn V-class vehicle capable of single launch Mars or Moon missions we could launch now. No thermal tile problems, or needing to master orbital refueling, or stretching tanks, or increasing Raptor thrust. It literally could have been launched on the last few test launches and can literally be launched on the next test launch, providing a proof-of-principle for manned flights to the Moon or Mars. Note this is less than the cost now for sending astronauts to the ISS.
I argue that this is better than the currently planned SpaceX/NASA approach. For instance the fully reusable Superheavy/Starship V2 will have payload at 100+ tons, and still need all of orbit capable TPS, orbital refueling, tank stretch and upgraded raptors. And it will need all of these to get a ca. $10 million reusable launch cost. But the Starship/mini-Starship will reach the same payload capability, at only be 1/3rd the size of the Superheavy/Starship, without the difficult technical advances.
The current approach to the Moon is not just worse, it's multiply times worse. SpaceX wants a multiple refueling, multiple launch approach of the full Superheavy/Starship for lunar missions. This will be in the range of 18 total flights with refuelings, the orbital depot, and the Starship HLS itself.
In contrast the Starship/mini-Starship can do it in a single launch. And the current plan needing ~18 launches will actually be 18*4 = 72 times bigger than using a single Starship. Taking into account the size also of the mini-Starship, the current multiple Superheavy/Starship lunar plan will be about 50 times the size of just the single Starship/mini-Starship.
Using an existing Falcon 9 upper stage or Centaur V as the 3rd stage/lander this is a capability we have now to do single launch Moon or Mars missions.
Keep in mind the ~$20 million price might be the customer price for the launch-to-LEO vehicle of the Moon or Mars flight. But SpaceX's own cost would be ~$10 million per launch. This is a capability SpaceX has now.
A comparison of the relatively sizes of the two approaches for getting to the Moon:
Compared to:
1 comment:
I think estimates of Starship inert mass less than 100 tons are utter nonsense! The prototypes being tested are running about 120 tons, and they are not even fully equipped to serve any purpose except experimental test. -GW Johnson
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