For most of spaceflight history, launching a rocket has meant throwing away a remarkably expensive machine after only a few minutes of use. SpaceX is attempting to change that model with Starship, an enormous launch system designed around one central idea: make essentially the entire rocket reusable.
Why Methane?
Starship's choice of methane (CH₄) is particularly interesting for long-duration space exploration.
Methane engines can be designed for reuse while producing less soot than kerosene-burning engines. Even more importantly, methane could potentially be manufactured away from Earth. Mars has an atmosphere dominated by carbon dioxide, while water ice exists beneath and around its surface. Through chemical processes such as the Sabatier reaction, hydrogen derived from water can react with carbon dioxide to produce methane.
A future Mars mission could therefore theoretically manufacture part of its return propellant on Mars rather than carrying all of it from Earth.
Catching a Rocket Instead of Landing It
One of Starship's strangest engineering features is its recovery system. Rather than always landing Super Heavy on conventional landing legs, SpaceX has demonstrated catching boosters with enormous mechanical arms attached to its launch tower.
The concept removes the mass of traditional landing legs and could eventually allow a recovered booster to be rapidly inspected, refueled and flown again. SpaceX sees rapid reuse as essential to making very high launch rates practical.
This is where Starship differs fundamentally from most previous rockets. A reusable rocket isn't truly revolutionary if rebuilding and inspecting it takes months. SpaceX is ultimately trying to make rocket operations behave more like aircraft operations, where the vehicle lands, is serviced and flies again.
Refueling a Spacecraft in Space
Reusability alone isn't enough for Starship's most ambitious missions. Traveling to the Moon or Mars requires enormous amounts of energy, so SpaceX plans to refuel Starship in Earth orbit.
A tanker Starship would launch propellant into orbit and transfer extremely cold liquid methane and oxygen to another spacecraft. This presents major engineering challenges because cryogenic liquids behave differently in microgravity and continuously absorb heat from their surroundings.
NASA's inspector general has identified large-scale vehicle-to-vehicle cryogenic propellant transfer as one of the most significant technical challenges facing the Starship lunar program.
From Earth Orbit to the Moon
Starship is also connected directly to NASA's future lunar exploration.
NASA is developing a specialized Starship Human Landing System (HLS) with SpaceX. The lunar version is roughly 50 meters tall and is intended to transport astronauts between lunar orbit and the Moon's surface during future Artemis missions. NASA is currently conducting additional testing, including wind-tunnel studies of the Version 3 Super Heavy configuration.
Starship remains an experimental system, and important capabilities—including routine rapid reuse and the full orbital-refueling architecture—still have to be demonstrated. But that experimentation is also what makes the project scientifically and technologically interesting.
If its major engineering goals can be achieved, Starship could change more than how rockets look. Large payload capacity, orbital refueling and rapid reusability could change what kinds of missions are physically and economically possible, from giant space telescopes and lunar laboratories to much more ambitious exploration of Mars.