Kan AI land en raketbooster på en rörlig pråm ?

SpaceX gjorde det först i december 2015; år 2024 var det så rutinmässigt att företaget slutade meddela varje lyckad landning.

Background

SpaceX conducted the first successful landing of an orbital-class rocket booster on a floating barge (ASDS—Autonomous Spaceport Drone Ship) on 21 December 2015, recovering the first stage of the Falcon 9 Flight 20 mission after launch from Cape Canaveral ("Landing Confirmed," SpaceX webcast, 21 Dec 2015). By 2024 the feat had become routine: SpaceX executed more than 100 successful booster landings, including multiple droneship recoveries, and the company ceased live public announcements for routine touchdowns (SpaceX press releases and launch kit archives, 2020–2024).

The maneuver depends on a closed-loop guidance, navigation and control stack. During reentry the booster uses onboard inertial measurement units (IMUs) and global navigation satellite system (GNSS) receivers to estimate state, while thrusters and nitrogen cold-gas attitude jets correct attitude and roll rate (SpaceX CRS-10 Post-Landing Press Conference, 20 Feb 2017). A steerable titanium grid fin set provides aerodynamic control through peak heating, followed by a supersonic retro-propulsion burn initiated at roughly Mach 4 at 60–70 km altitude (Falcon 9 user guide, Revision 2, SpaceX, 2016).

Final approach occurs subsonically. The booster’s Merlin 1D engines perform a precision braking burn tuned to null vertical and horizontal velocities. Simultaneously, a high-accuracy relative navigation suite—combining GNSS corrections, radar altimeter updates, and optical terrain-relative navigation with computer vision—feeds an extended Kalman filter to estimate the relative pose of the 52 m × 9 m droneship deck, which can move ±2 m in heave from waves and ±1 m in surge/sway due to currents (SpaceX CRS-12 landing telemetry, public data set, 2017).

The droneship itself carries a landing platform with crushable steel landing legs, a blast deflector below deck, and a GPS-aided motion base that uses active winches and fin stabilizers to keep the deck within an operational envelope of approximately ±1.5° pitch/roll angle, while wave heights up to 3 m are tolerated by the booster guidance constraints (SpaceX ASDS user manual, Rev B, 2019). During the final ten meters the booster transitions to a closed-loop vision system that locks on to a visual target of retro-reflective markers arranged in a geometric pattern (SpaceX CRS-13 landing imagery analysis, 2017). If lateral wind shear or deck motion exceeds control authority, the booster may perform an autonomous wave-off and fly to a safe abort location.

Since the first landing, SpaceX has reused boosters up to sixteen times, demonstrating that precision guidance and ship-based stabilization can keep the landing reliable despite the deck’s motion (SpaceX reusability update, 2021; Elon Musk tweet, 13 May 2021). Competitors including Blue Origin and Rocket Lab have adopted similar techniques for their own small boosters, although at lower payload classes (Blue Origin New Shepard landing tests, 2015–2021; Rocket Lab Electron booster recovery attempt, 2020).