[theultdev]

> There's no proof yet reuse is actually cheaper.

What a ridiculous statement...

This just in, blowing up your car is cheaper than refilling the tank, wow!

There's proof right now btw, in SpaceX's Falcon prices vs others.

Plus the common sense that remaking something is more expensive than not.

[mahkeiro]

That's not ridiculous the Space shuttle is the proof that reusable can be tricky… however for falcon 9 there is few doubt that it must be cheaper.

[theultdev]

I'm talking about cheapest overall.

Done properly, reusable will always be cheaper, inheritly.

[mandevil]

There is a mathematical equation, a function of variables, on whether the reuse business case closes. The variables are, off the top of my head (I might have missed some) the base carrying cost of all the people necessary to run the space-ship factory, the incremental cost of refurbishing the rocket and the incremental cost of building a new one, plus the overhead both in payload and engineering effort to get that reusability. The result of the equation is how many flights per year is necessary for re-usability to pay off.

So for the Space Shuttle reusability did not pay off, because it had a low flight rate and a very high cost of refurbishment (the Solid Rocket Boosters in particular probably never paid off- due to the landing into the ocean and the salt-water dunking they had to be fully taken apart after every flight, inspected, and put back together, and that meant that you actually had labor costs of twice the work of just assembling a new one- the materials cost savings was simply not worth that). This is one reason that SpaceX ended up abandoning their original plan of recovering engines from the ocean, though they were trying to do it much harder with liquid fuel engines rather than the simple solids that STS used.

One interesting thing about SpaceX (a privately held company, which does not publish useful financials) is that they have also claimed they invested a lot into the factory for churning out engines with many fewer man-hours than their western competitors. That investment might not make sense if you are counting on reusing all your engines many times before they are replaced- unless you are looking at many many launches of Falcon Heavy, which I will be curious to see if they actually do (the market for super heavy rockets like that has never really existed at more than 5ish a year, and I'm personally uncertain if satellite internet can get there).

Before SpaceX came along, the (Russian) Progress company was the cheapest in the world, with their R7 Semyorka (Soyuz 2 is the modern version) rocket family. That was because the Soviet Union had invested in a very heavily automated, highly productive launch factory (they launched a bucket-dropping spy satellite every two weeks, plus manned launches, Progress resupply flights, Molniya commsats, etc. so they had a very high flight rate) that needed very little in the way of manpower to make their engines and rockets- and that investment definitely paid off, the R-7 family has flown into space more than any other rocket in human history. But making it reusable and investing heavily in highly automated production tend to cut against each other as solutions to the cost problem until you get to extremely high flight rates.

Whether you think that at current flight rates the numbers point to re-usability comes down to how much you trust Musk the businessman (personally not very much), and how much you trust Shotwell to manage Musk and bring the company to a good place in spite of Musk's random perturbations (personally I have great faith in Gwynne, but your mileage may vary).