Aviation week article on SpaceX reusability

[Nomadd]

 A change of plans is not a "paradox".

[john smith 19]

A change of plans is not a "paradox".

No, the paradox is that if you want a lot of something then you need to freeze the design and commit to making that design, but the design is not frozen.

So yes your N+1 iteration may be better than your current version, but you'll never stop updating long enough to make the 33 (or whatever they are currently needing) to load up a full SH booster.

The other alternative is to just sling the last X number of Raptors on the structure and see what happens. Hope their EMU's can keep them all in synch with regard to thrust and MR during the flight (is it my imagination or is Musk trying to go back to a no EMU design? I could have sworn I read something about this).

The usual solution to this dilemma is a)Freeze the design b)release to mfg c)Continue to refine a test unit(s) but  confine changes that will allow them to be dropped into the existing vehicle d)When you've got enough improvement (by whatever metric is relevant to you) release the new version to mfg.

IOW Block upgrades.

However WRT this threads title while increasing the Pch and the operating temp can make substantial improvements to Isp they are likely to make the whole design a bit more fragile.

 The only real way to quantify how much more fragile is to get them off the stand and put enough on a SH to put an actual SS on it, and repeat that till something breaks. 

It's a cliche but the only real test of reusability is to actually try reusing something.

[FutureSpaceTourist]

Notice that boosters going over 10 flights are doing only StarLinks.

That’s mostly true and yet the new record 14th (and successful) flight of B1058 tonight was a rideshare with the BlueWalker3 customer satellite.

Elon also tweeted:

https://twitter.com/elonmusk/status/1568788727014752257

No obvious limit to rocket reflight so far

So I think SpaceX are definitely going to push past the 15 flights target.

[M.E.T.]

Back of the envelope - if an F9 booster costs $30M to build, 15 uses gets that cost down to $2M per flight. Add $1M for refurbishment and we are now as low as $3M booster cost per flight, all inclusive.

Add $10M for the 2nd stage, $2M for reused fairings, and $2M for flight operations, fuel and ocean recovery, and we are therefore at a total cost per launch of approximately $17M.

That’s for 16 tons to LEO. Remarkable.

[john smith 19]

Back of the envelope - if an F9 booster costs $30M to build, 15 uses gets that cost down to $2M per flight. Add $1M for refurbishment and we are now as low as $3M booster cost per flight, all inclusive.

Add $10M for the 2nd stage, $2M for reused fairings, and $2M for flight operations, fuel and ocean recovery, and we are therefore at a total cost per launch of approximately $17M.

That’s for 16 tons to LEO. Remarkable.

And at around a $63m launch price that's a 270% profit.

If the development process cost (as I think Musk stated) $1Bn then 21 paying customer launches (IE not starlink) would have recovered the costs and start making pure profit.

Of course to the customer the price is still the same.

A situation I don't expect will start to change until Neutron starts launches and customers have a real choice in semi-reusable launch systems.

[FutureSpaceTourist]

We already have a Neutron vs F9 & SS thread:

https://forum.nasaspaceflight.com/index.php?topic=55413.0

So the last page of discussion has magically moved there.

Back to the Aviation Week article …

[AmigaClone]

It appears that Elon is suggesting that soon at least some of the F9 Block 5 boosters might receive intensive checks to support certifying them to twenty flights, an increase of five compared to the fifteen flights mentioned in the article.

https://twitter.com/elonmusk/status/1568788727014752257

[AC in NC]

It appears that Elon is suggesting that soon at least some of the F9 Block 5 boosters might receive intensive checks to support certifying them to twenty flights, an increase of five compared to the fifteen flights mentioned in the article.

While I wouldn't be surprised if they follow through on the previously-suggested plan to pull one for checks at 15, I'm interpreting that quote as they might keep pressing forward and wait for standard refurbishment inspections to suggest the need for intensive check-out/certification.

[OTV Booster]

It appears that Elon is suggesting that soon at least some of the F9 Block 5 boosters might receive intensive checks to support certifying them to twenty flights, an increase of five compared to the fifteen flights mentioned in the article.

While I wouldn't be surprised if they follow through on the previously-suggested plan to pull one for checks at 15, I'm interpreting that quote as they might keep pressing forward and wait for standard refurbishment inspections to suggest the need for intensive check-out/certification.

One purpose of the deep inspections is to determine the interval needed for deep inspections. My experience with mechanical life cycles is it starts with rapid wear, called break-in, followed by a long period of near steady state with a slow rate of wear. The last stage, where wear is unacceptable all too often shows wear accelerating rapidly. This has to be caught.


If post flight checks can monitor this without a tear down - cool. Think checking crank shaft thrust bearing play by yanking on the harmonic balancer instead of opening the engine. If it's more like valve guide play it can be checked by partial tear down but far less than pulling the head.


I'd expect to see some systems getting closer attention than others after 5*N flights. Maybe see swappable units to allow deeper inspection. Sort of like getting a refurb/reman alternator for your car.

[sghill]

Add $10M for the 2nd stage, $2M for reused fairings, and $2M for flight operations, fuel and ocean recovery, and we are therefore at a total cost per launch of approximately $17M.

That’s for 16 tons to LEO. Remarkable.

It's less than that. They can start depreciating the $10 booster cost now that it isn't being thrown away.

[OTV Booster]

Add $10M for the 2nd stage, $2M for reused fairings, and $2M for flight operations, fuel and ocean recovery, and we are therefore at a total cost per launch of approximately $17M.

That’s for 16 tons to LEO. Remarkable.

It's less than that. They can start depreciating the $10 booster cost now that it isn't being thrown away.

Uh, it doesn't work that way.
If a booster costs a nominal $30m a pop and it's not reusable it's a straight $30m deduction. Actually it's not one big deduction but ongoing deductions for everything that goes into building it.


If it's reusable, well I don't think the IRS has guidance for reusable rockets. Any way it has to be declared as a 3, 5, 10, 15, 20 or 30 year property. Let's ignore accelerated depreciation. Makes it too complicated. The labor and materials that goes into building the reusable booster is not deducted as it would be for a throwaway. It gets credited to an account that represents the 'basis' of that booster.


If it costs $30m to build (the basis) and it's declared to be a five year property, every year they can claim $6m depreciation, which essentially acts as a deduction from income before taxes are calculated. In other words, they deduct the cost of building the booster over its expected lifetime. There is an amazing amount of niggling and maneuvering associated with depreciation but this is it at its simplest.

[john smith 19]

That’s for 16 tons to LEO. Remarkable.

For SX profit margin yes it is.

As a customer, so what?

[M.E.T.]

That’s for 16 tons to LEO. Remarkable.

For SX profit margin yes it is.

As a customer, so what?

It means if SpaceX wants a launch customer, they have room to drop to a price of $17M and still break even, while any competitor with a higher cost rocket does not have that luxury.

You stubbornly insist on viewing F9 as a $65M rocket when assessing the prospects of would-be competitors. That is wrong. You need to compare the cost of the respective rockets, to really understand what any new competitor is up against. F9 is a $17M rocket.

That is the true reflection of the exercisable market power that SpaceX has.

[FutureSpaceTourist]

So this thread went completely off the rails …

I’ve pruned right back and restoring it locked (for reference). I’ll unlock if anyone has something on topic that they’re keen to share (but will permanently lock if it goes off the rails again).