What is a SpaceX droneship? The robot barge that catches rockets at sea

Half of SpaceX's rocket landings don't happen on land at all — they happen on a football-field- sized robot barge floating hundreds of kilometres out in the ocean. These are the droneships, and landing a 40-metre booster on a bobbing deck is every bit as wild as it sounds. Here's what they are, why they exist, and a free game, LANDING BURN, that drops you onto one.

▶  LAND ON THE DRONESHIP — FREE

What it actually is

Officially it's an Autonomous Spaceport Drone Ship (ASDS) — a converted barge topped with a huge steel landing deck and no crew aboard during a landing. SpaceX sails it out to a precise spot in the ocean, where it holds position using GPS and powerful thrusters, riding out the swell, and waits for a booster to drop out of the sky onto it.

Why not just land on the ground?

Flying the booster all the way back to the coast — a "return to launch site" — burns a lot of fuel, and fuel spent landing is payload you can't carry. For heavier or higher-energy missions, the booster simply doesn't have the propellant to turn around and come home. So SpaceX parks a droneship downrange, right under the booster's natural path, so it can land with a much smaller landing burn. It's a core part of making reuse pay off.

The names (yes, really)

SpaceX named its droneships after sentient starships from Iain M. Banks's science-fiction novels: Of Course I Still Love You, Just Read the Instructions, and A Shortfall of Gravitas. It was on A Shortfall of Gravitas that a Falcon 9 booster recently notched its record-setting 35th landing.

Why it's harder than land

• The target moves. The deck rises and falls with the sea, so the booster is aiming at something that isn't holding perfectly still.
• It's smaller than it looks. The deck is big for a ship but tight for a rocket falling from space at the end of a launch.
• One shot. Like any booster landing, it ends with a single late burn — no hover, no second attempt.

Try the landing

The first mission in LANDING BURN is exactly this: bring a Falcon 9 down onto the droneship deck within tight limits on speed, drift and tilt. Fuel left over is your score — so the smart play is the same one SpaceX makes: burn as late as you dare. Free, in your browser.

▶  FLY THE DRONESHIP LANDING NOW

FAQ

How does the droneship stay still?

It uses GPS and powerful azimuth thrusters to hold its position against wind and waves during the landing.

Is anyone on board during a landing?

No — it's autonomous and uncrewed during the landing for safety; support crews stay on a nearby vessel.

When does SpaceX use a droneship vs landing on land?

Droneships are for higher-energy missions where the booster can't spare the fuel to fly back; lighter missions land back at the coast. See how SpaceX lands rockets.

Can I try it without downloading?

Yes — LANDING BURN runs in any browser and on phones, free.