Why return of Falcon 9's first stage is a big deal

SpaceX’s ultimate goal is to develop cheap space transportation.

Elon Musk started with a vertical integration strategy (akin to Apple’s) in order to bring the costs down. NASA, on the contrary, is obliged to hire contractors in order to justify its funding (and thus create many jobs). In addition space regulations created many risk-averse and even cost-maximising incentives. One of the main NASA’s rocket-launching company, ULA, is compensated based on how much they spend. ULA charges NASA >400$m per lauch, whilst SpaceX, currently, ~120$m. Possibility of corruption on the national level is also not excluded. In fact, Elon said that his family fears that Elon might be assassinated¹. (Note that SpaceX charges other clients ~65$m, but NASA is finicky).

The idea of reuse isn’t new and that’s exactly what Shuttle was designed for. However there’s a crucial strategic difference. Rather than developing reusable rockets from ground up, Elon’s plan is to run a profitable space-delivery business whilst developing reusable technology incrementally as an additional feature. With 1100 active satellites orbiting the Earth the market for space deliveries is large and Elon’s first step to slash the costs down via vertical integration worked out quite well: SpaceX has more demand at the moment than they can fulfil. Such fast iteration on designs allowed by frequent launches and subsidised testing of reuse technology by the clients is why SpaceX’s approach is very promising.

Today was just one of those missions. Falcon 9 actually delivered 11 satellites into the orbit, meaning its first stage was well above the atmosphere of the Earth travelling at the ~2km/s on a parabolic trajectory after the separation. Usually the first stage is left to burn on re-entry. This would have turned ~40$m worth of material into rubbish. Prior vertical landings were achieved with rockets hopping up and down at much slower speeds. Falcon 9 didn’t land where it took off. This is why today’s feat is unprecedented: the parabolic trajectory. However until the returned first stage is actually reused we can’t herald the new era quite yet.

Other design decisions for Falcon 9R (R for reusable) to be economically viable: reuse vertical landing technology for stage 2 by equipping stage 2 with similar engines to stage 1. At the moment Falcon 9’s first stage consist of 9 Merlin engines and stage 2 has a modified Merlin engine (to take advantage of the vacuum). Many space agencies spend more investment on stage 2 engines, thus achieving more thrust per buck (again due to vacuum). But they develop an incentive to not care about returning cheap stage 1. However it is easier to develop the return of stage 1 because its slower than stage 2 after separation.

None of the numbers are accurate. Read more on SpaceX on waitbutwhy (163 pages long pdf warning):