Definition
The series of government and industry projects prior to SpaceX that attempted to lower launch costs through reusable hardware, most of which failed to achieve economic viability due to high maintenance costs and political shifting.
Why It Matters
They provide the context for the decades-long struggle to lower the cost of spaceflight, highlighting why past attempts failed and why current successes are so revolutionary. Learning from these historical “failures” is what finally allowed for the breakthrough of orbital-class landing.
Core Concepts
- Space Shuttle (1981–2011): The world’s first reusable spacecraft. Failed the “low cost” goal due to extreme maintenance (e.g., 21,000 hand-inspected thermal tiles) and standing armies of technicians. Final cost: $25,000/lb (vs. $25/lb goal).
- DC-X (Delta Clipper, 1991–1996): An experimental project by McDonnell Douglas (Strategic Defense Initiative) that proved vertical takeoff and vertical landing (VTVL) with a small-scale prototype. Casualty of “rocket politics” and NASA’s preference for winged space planes.
- X-33 (1996–2001): A Lockheed Martin concept for a single-stage-to-orbit space plane. Failed due to the technical difficulty of building cryogenic liquid hydrogen tanks from composite materials.
- Space Launch Initiative (2001): A broad NASA attempt to develop new reusable technologies, canceled in 2004 in favor of expendable “Apollo-style” rockets.
- Economic Viability Condition
- How to read: “Economic viability is achieved if and only if the refurbishment cost plus the vehicle cost divided by the number of flights is less than the cost of a new vehicle.”
- Meaning: Reusability only wins when per-flight cost (refurbishment + amortized vehicle cost) beats building a new expendable each time.