European Spaceflight
Booster recovery
Flying the first stage back and landing it, so the expensive part is not thrown away.
The first stage is most of the cost of a launcher and it separates while still relatively low and slow, which makes it the one part worth bringing home. Recovery costs performance — propellant reserved for the return is propellant not spent on the payload — so a heavy mission flies expendable and a light one lands. The economics only work with a fast turnaround; a booster that lands and then needs a year of inspection has saved nothing. The current generation flies again within weeks, and individual boosters have flown more than twenty times.
Where it has come up lately
Related terms
Delta-v
The currency of spaceflight: how much you can change your velocity, in metres per second.
NET (no earlier than)
A launch date that is a lower bound, not a promise.
Max-Q
The moment of peak aerodynamic pressure on an ascending rocket.
Staging
Throwing away the empty part of the rocket so you stop accelerating it.
Questions
What is Booster recovery?
Flying the first stage back and landing it, so the expensive part is not thrown away.
Why does it matter?
The economics only work with a fast turnaround; a booster that lands and then needs a year of inspection has saved nothing. The current generation flies again within weeks, and individual boosters have flown more than twenty times.