Reusable rockets change launch economics by treating the booster as an expensive vehicle instead of disposable hardware. A first stage can make up a large fraction of a launch vehicle's cost, so recovering it can save money if it can fly again safely. The main question is not whether landing is impressive, but whether the added systems, fuel, inspections, and repairs cost less than building a new booster.
This is why engineers compare total cost over many flights, not just the cost of one launch.
Key Facts
- Expendable cost for N launches: C_exp = N(C_booster + C_upper + C_ops)
- Reusable cost for N launches: C_reuse = C_dev_extra + C_booster + N(C_upper + C_ops + C_refurb + C_recovery)
- Break-even occurs when C_reuse = C_exp.
- Average booster cost per flight decreases with reuse: C_avg_booster = (C_booster + C_dev_extra)/N + C_refurb + C_recovery.
- Recovery hardware and landing propellant reduce payload capacity, so economic gains must outweigh performance losses.
- Fast turnaround improves reusability economics because fixed costs are spread over more launches per year.
Vocabulary
- Reusable booster
- A rocket first stage designed to return, land, be refurbished, and fly again.
- Refurbishment
- The inspection, repair, cleaning, testing, and replacement work needed before a recovered booster can launch again.
- Break-even point
- The number of flights at which reusing a booster costs the same as or less than building a new one each time.
- Recovery hardware
- Extra equipment such as landing legs, grid fins, control systems, and thermal protection used to bring a booster back safely.
- Turnaround time
- The time required to prepare a recovered booster for its next flight.
Common Mistakes to Avoid
- Ignoring refurbishment cost makes reuse look automatically cheap. A landed booster only saves money if inspection, repair, and testing are much cheaper than manufacturing a new booster.
- Counting the first reusable flight as pure savings is wrong. The first flight still includes the cost of the booster and the extra recovery systems, so savings usually appear after several flights.
- Forgetting the payload penalty gives an incomplete comparison. Landing fuel, legs, fins, and stronger structures can reduce how much payload the rocket can carry to orbit.
- Assuming every recovered booster can fly many times is unrealistic. Hardware fatigue, engine wear, landing damage, and safety rules can limit the useful lifetime of a stage.
Practice Questions
- 1 A new expendable booster costs 55 million to build, plus $6 million for recovery and refurbishment after each flight. Ignoring upper stage and operations costs, after how many flights does reuse become cheaper than buying a new booster each time?
- 2 A reusable booster has a build cost of 5 million per flight. If it flies 10 times, what is the average booster-related cost per flight? Compare this with a $60 million expendable booster used once.
- 3 A rocket company adds landing legs, grid fins, and extra propellant to recover its booster, but this reduces payload capacity. Explain what economic factors determine whether recovery is still worth it.