Reusable second stage is only a matter of time as well.
Fully reusable rockets in maybe 5 years.

Your spreadsheet is quite telling, despite any “really stupid errors” you may have made. Despite the dramatic improvement due to the cost of the reusable first stage, the cost of the second stage keeps the overall cost-to-orbit rather high, only about 1/3 the one-use cost. This would explain why Musk has mentioned a desire to make a reusable upper stage and why others would like a single-stage-to-orbit vehicle or are proposing to return and reuse only the (expensive) engines. The less hardware that is thrown away after each use, the less expensive the cost to orbit.

It also shows that the payload cost to orbit starts looking asymptotic after about 10 reuses (diminishing returns), and the cost of the first stage starts looking asymptotic after about 20 launches. Thus, even if a stage can only be used a limited number of times (e.g. 10 or 20), much of the savings we could expect of an infinitely reusable stage have already been obtained, meaning that the hardware does not have to last for hundreds or thousands of launches in order for it to save a lot of money.

We can also see that this is not an evolutionary (read: “incremental”) improvement in rocketry but a revolutionary improvement. Both SpaceX and Blue Origin should save a lot of money and become significantly more efficient than traditional competitions. (Blue Origin’s scientific payload competition is the one-use sounding rocket, but their manned-space competition, Virgin Galactic and XCOR, already intend to reuse their hardware for similar savings.)

Thank you for putting this together and sharing it.

Anything in yellow can be changed. I probably will notice a really stupid error in the morning.

Don’t forget, SpaceX has considerable time with Grasshopper and I’m sure gained experience with this “soot”.

The difference between paint burning off and re annealing or heat treating of metals is quite a bit even for aluminum sheets (650-800deg) making up the outside of the rocket.

I normally use for all my metalwork. They are cheap and work great. http://www.tempil.com/temperature-indicators/

If SpaceX wants to know almost exactly what the temp is for any spot on the rocket they can just tag a grid of these marks bracketing the expected temp and they will get within 1% or so of actual temp. Up to about 2500deg.

The only temp problems should be on the super high temp engine parts and if they can’t take the temp of launch they shouldn’t be used more than once, if at all.

With these assumptions, I used the number of launches for the last two years and SpaceX would have saved $144m in 2014 and $179m in 2015.

The big savings start to taper off after the 20th launch going from in the hundreds of thousands in saving to the tens of thousands. It would take 42 launches to bring the cost per launch down to $20m but the 100th launch would cost $19.42m

But this was just the simplest analysis and those numbers are based on my assumptions which are not accurate in the real world.

What a nice side benefit.

Thanks for the correction. I have revised the post accordingly.

I suspect you are correct about the non-existence or triviality of overall “damage” to the stage. I had earlier speculated that the greyish tinge of the upper and lower thirds of the stage was due to burning of the paint, but this closeup view makes it look to be mainly a coating of soot. The paint on the stage’s sides looks a lot more intact than I expected it to. The paint on the grid fins looks worse as one would expect as they are deployed directly into the teeth of the hypersonic slipstream beyond the boundary layer. The presence of engine soot all the way up the booster stage exterior suggests that the engine exhaust gases generated when three Merlin 1-D’s are re-lit for the re-entry burn form a comparatively cool envelope around the entire length of the stage and prevent the ambient atmosphere at hypersonic stagnation temperature from ever impinging directly on any part of the stage’s structure. This also suggests that speculations I have seen in other venues about the possible “de-tempering” or “de-heat-treating” of the booster stage’s metal components during re-entry are baseless.

In short, it looks like prep for re-use will consist mainly of a pressure wash and paint touch-up. SpaceX may already be designing a 1st-stage “car wash” to automate much of this work.

Small wonder NASA is so interested in the data SpaceX derives from these booster flybacks/re-entries. Hypersonic re-entry into the thin upper atmosphere of Earth looks to be quite a good model for the engineering of future large Mars landers.