Starship: SpaceX’s most powerful rocket for the Moon and Mars

01What Starship is

Starship is a two-stage, fully reusable launch system made of stainless steel: a giant first-stage booster called Super Heavy and an upper stage — the spacecraft itself — also called Starship. Together they stand about 121 metres tall and are designed so that both stages return and fly again.

SpaceX built it for one overriding purpose: to make life multiplanetary. The same vehicle is meant to launch satellites, land NASA astronauts on the Moon under Artemis, and eventually carry the first crews and cargo to build a base on Mars. Full reusability is the point — it is what could finally make spaceflight cheap enough to move a settlement’s worth of mass off Earth.

02How Starship came to be

The idea evolved through several names. In 2016 Elon Musk unveiled the Interplanetary Transport System (ITS); in 2017 it was reworked as the Big Falcon Rocket (BFR); and in 2018 SpaceX settled on today’s names — Starship for the ship and Super Heavy for the booster. Prototypes followed quickly, from the squat "Starhopper" to the tall high-altitude test articles.

03How Starship is built

Upper stage (Starship)

• A crew or cargo bay in the nose (payload volume larger than most space stations’ pressurized volume).
• A heat shield of ceramic tiles on the windward side for atmospheric re-entry.
• Four aerodynamic flaps that steer the belly-first descent.
• Its own Raptor engines (sea-level + vacuum) and control systems.

First stage (Super Heavy)

• A stainless-steel booster holding the bulk of the propellant.
• A cluster of 33 Raptor engines at its base.
• Grid fins and a return profile that lets the launch tower’s arms ("chopsticks") catch it.

04Technical specifications

Approximate figures for the full stack; they change between Block versions as SpaceX iterates.

05Raptor engines

Raptor is the engine that makes Starship possible. It burns liquid methane and liquid oxygen (methalox) in a full-flow staged-combustion cycle — one of the hardest engine cycles to build, and among the most efficient. SpaceX has iterated through Raptor 1, 2 and 3, each simpler, cheaper and more powerful.

06Why methane fuel

• Efficiency — methalox offers high performance with a manageable engine design.
• It can be made on Mars. The Sabatier reaction turns Martian CO₂ and water into methane, so a return ship refuels locally (ISRU).
• Cleaner burning — methane leaves far less soot than kerosene, which helps reuse the engines quickly.
• Cost and handling advantages over hydrogen (which is bulky and hard to store).

07How a Starship launch works

• 1. Liftoff — all 33 Super Heavy engines fire.
• 2. Hot-stage separation — Starship’s engines light before the stages fully part.
• 3. Booster return — Super Heavy flies back to be caught by the launch tower.
• 4. Orbit — Starship continues to orbital velocity.
• 5. Refuelling — for deep-space trips, it tops up from tanker Starships in orbit.
• 6. Transit — the ship coasts to the Moon or Mars.
• 7. Landing — it re-enters, flips upright and lands propulsively.

08Orbital refuelling

Starship reaches orbit nearly empty of propellant, so any trip beyond needs refuelling in space. Tanker Starships launch, dock with the vehicle in Earth orbit and transfer methane and oxygen, filling its tanks for the journey to the Moon or Mars.

• Why it matters — it is the key that unlocks the Moon and Mars with a single vehicle.
• The hard part — transferring cryogenic propellant in microgravity has never been done at this scale.
• Several tanker flights may be needed to fill one Mars-bound ship.

09Full reusability

Unlike Saturn V or the SLS, Starship is designed so that nothing is thrown away. The Super Heavy booster returns to be caught by the tower’s arms, and the ship re-enters and lands to fly again. If it works routinely, the cost per flight could fall dramatically, because only fuel and refurbishment — not the rocket — are spent each time.

10Flight testing

SpaceX develops Starship by flying hardware early and often, learning from failures. The program has moved through clear phases.

11Starship and the trip to Mars

• Carrying crews — ferrying the first settlers on the ~6–9 month transit.
• Delivering cargo — landing the mass a base needs before people arrive.
• Building the base — bringing habitats, power systems and machinery.
• Moving equipment — rovers, drills and construction robots.
• Resupplying the colony on each launch window.

12Starship and the Artemis program

NASA selected a lunar version of Starship as the Human Landing System (HLS) to put Artemis astronauts on the Moon’s surface. The Moon variant drops the flaps and heat shield it doesn’t need there, and relies on the same orbital-refuelling approach. It works alongside NASA’s SLS rocket and Orion capsule, which carry the crew to lunar orbit.

13Cargo capabilities

• Large batches of satellites in one launch.
• Modules for space stations.
• Heavy cargo for Mars and Moon missions.
• Scientific and government payloads.
• Oversized structures that no other rocket can fit.

14The crewed version

• A design goal of up to ~100 people on long-duration Mars flights.
• Living quarters, common areas and storage in the pressurized nose.
• Life support — air, water and food systems for months in transit.
• Radiation shelter and redundancy for crew safety.

15Landing on Mars

• Atmospheric entry — hitting the thin Martian air at high speed, protected by the heat shield.
• Aerobraking — using that atmosphere to shed most of the velocity.
• Propulsive touchdown — Raptor engines flip the ship upright and land it.
• Site selection — flat ground near buried ice for fuel and water.
• Risks — Mars’ thin air makes landing large mass one of the hardest parts of the mission.

16Making fuel on Mars

Starship’s methalox fuel is the reason it can come home. Rather than carry return propellant all the way from Earth, the plan is to make it on Mars.

• Mine water ice from beneath the surface.
• Electrolyse water into hydrogen and oxygen.
• Run the Sabatier reaction: CO₂ + hydrogen → methane + water.
• Store the cryogenic methane and oxygen for the return launch.

17Safety

• Engine-out capability — with 33 booster engines, some can fail and the flight continues.
• Heat shield protecting the ship through re-entry.
• Redundant systems for critical functions.
• A test-heavy development approach to find failures before crews fly.
• Crew-protection design still maturing — human flights follow extensive uncrewed testing.

18How it compares to other rockets

At about 74 meganewtons of liftoff thrust, Super Heavy is the most powerful rocket stage ever flown — roughly twice the thrust of the Saturn V that sent Apollo to the Moon.

19The economics

SpaceX self-funds most of Starship’s development, with total spend widely estimated in the several-billion-dollar range. The economic case rests on reuse: if a vehicle flies many times with only fuel and refurbishment between flights, the cost per launch could eventually fall to a small fraction of today’s heavy rockets. SpaceX’s long-term cost targets are aspirational and unproven — treat specific per-launch numbers as goals.

20The future of Starship

• Routine, rapid-reuse flights from multiple launch sites.
• Landing crews on the Moon and helping build lunar bases.
• Carrying the first cargo and people to settle Mars.
• Space tourism and point-to-point ideas.
• Becoming the backbone of interplanetary logistics.

21Interesting facts

• Starship is the tallest and most powerful rocket ever built.
• It is made of stainless steel, not the aluminium or composites of most rockets.
• It burns methane instead of the kerosene used by Falcon 9.
• The Super Heavy booster is designed to be caught in mid-air by the launch tower.
• It is meant to be fully reusable — both stages fly again.
• Its liftoff thrust is roughly double that of the Saturn V.
• The ship re-enters belly-first, then flips upright to land.
• Its methane fuel was chosen partly because it can be manufactured on Mars.
• NASA picked Starship to land astronauts on the Moon under Artemis.
• One Starship’s payload volume is larger than the pressurized volume of the ISS.

22Program timeline

23Glossary

24Frequently asked questions

25Sources

• SpaceX — Starship ↗
• SpaceX — Mission to Mars ↗
• NASA — Artemis Human Landing System ↗