The Pod Bay

12:46 AM

A very interesting image of the SN9 scrap.

And some Raptor guts...

XKCD

1:26 AM

If you had an oven bag and a dryer that runs unusually hot, I guess you could in theory make tumbled eggs.

9 hours later…

10:48 AM

@geoffc Some say that the state of the raptors is not enough stable for such tests, first it would need much more pad testing. They suspect, it is being done, and these launches have more PR reason. This is contradicted by that the cost of a single raptor is $40million, so sacrificing 3 raptors + a ship prototype might be too costly for a PR show.

@geoffc What is not very clear: if they knew that the raptors won't work very well for sure, why they did not write the program so that it uses the third raptor if one of them does not start?

Maybe... it is easy to say what should have been done than actually doing it before the events

11:35 AM

Where did you get the cost of a Raptor at $40 million? Musk has suggested they are either under 1 million or getting there.

12:27 PM

@peterh-ReinstateMonica You keep asking, why not start all three, then shut down the unneeded one for redundancy?

twitter.com/elonmusk/status/1357256507847561217

See Elon's tweet.

@geoffc Afaik it is a sell price. Possibly it might be cheaper, particularly if we count, how does it increase the expenses of the SpaceX to produce 1 more. (Which is a different price if we divide the cost of the whole raptor program by the count of the manufactured raptors.)

@geoffc :-) Self-critics is good but I think it is not true. They wanted to be quick and lost. That SN9 lands safely, it had been a possible outcome (someone estimated 50% to a successful landing, as it was yet in the air).

Probably now they collect data, fix/improve the raptors and the rocket, then a new launch will happen. I think SN10 might be launched in mar or apr (my extrapolation from existing launch pad activity dates).

@peterh-ReinstateMonica Where did you find cost of entire Raptor program and # produced to do that division?

Where did you see $40 million quoted as price for a Raptor? Cannot be sell price, since it is not actually for sale to anyone.

By your math, with 50+ Raptors built at $40 million per, that is $2 billion just on Raptor development? That seems a bit high for SpaceX.

@geoffc I've read the $40M in the net. The source seemed believable, but I did not verify it. Possibly it might be bad info (particularly if they are not (yet) for sale). No calculation was included.

I think $2bln is not a very high to develop a reusable FFSC engine.

12:46 PM

And to be fair, whatever number you saw, was likely long before they had built 50+ engines. we saw #45 fly on SN9 and I think we have seen #49 on one of SN8/9 vehicles.

I know someone caught #52 on the McGregor test stand.

$40 million sounds like the Air Force contract to develop the raptor engine in part from some time ago...

The cost of a raptor is quite a bit less than $40 million...

1 hour later…

2:06 PM

@PearsonArtPhoto How less? As far I know, the cost (well.. price) of an engine for the SLS will be tremendous

I've heard that the steady state cost of a Raptor will be less than a million.

The development cost I would guess is around $100 million, and probably about the same for all of the engines produced to date, but the cost is starting to drop pretty dramatically.

RS-25E by AJR is NOT anything like Raptor. SpaceX is nothing like AJR. So comparing the two is beyond apple and bears comparisons.

@PearsonArtPhoto Where did you hear 100 million dev costs? Curious to that source. And as you say, with 52 engines at least built so far, and 2 Boosters under construction that potentially needs 56 more engines in theory. (Yes, BN1 will probably use just 2 engines at first, but they are not stopping at 2 or event 10 boosters, probably).

So they are likely to quickly churn out 100-200 engines in the next year or so.

2:25 PM

It's just a guess, based in part on some Air Force development contract for the Raptor that partially funded it at around $50 million.

3:00 PM

@geoffc Why they don't develop a lesser amount, but bigger engines? I think they could be more cost effective

@peterh-ReinstateMonica again, I suggest, why do you think that? I do not agree, and I think that history has shown time and again that smaller engines are cheaper to both develop and build. Why do you thik history is wrong? do you have an example of a larger engine being cheaper than mass producing smaller engines?

Was the F-1 cheaper than the J-2? (I actually do not know the answer to that). Also not fair isnce one was RP1 and other was Hydorgen. Different problems.

But I think Spacex has demonstrated that building at scale is hugely cheaper than small number of engines. Consider Raptor vs RS-25E restart. I will accept your $50 mill/engine. Well ARJ got $124 million/engine. And they are close in size.

And one of the reasons I doubt the 50 mil value is, no way would SpaceX risk $150 million in resources like that. But if the dev cost is $2 billion total (so far) as you suggest, then the next 100 engines they need to build this year alone, would drop the per engine cost to 13 million/engine.

And then in the next year the 200 more would drop it closer to 5 million, assuming no other optimizations. (And sure i am ignoring incremntal cost of materials, since at the level of 50 million dollars, raw materials ain't the factor that matters)

4:03 PM

@geoffc I am not sure in my source. I am not sure in anything I read.

I am quite sure that the cost per engine is much less than $50 million for a Raptor.

It is closer to $2 million if anything now, I'm certain I've seen that.