Reusable Launch Vehicle (RLV)

Historically, most rockets were expendable—their stages were discarded after fuel exhaustion and fell back to Earth. NASA’s Space Shuttle was a partial exception, reusing the orbiter, but still discarding boosters and fuel tanks.

SpaceX, led by Elon Musk, aimed to reduce launch costs through reusability. Its Falcon 9 became the first orbital-class rocket to successfully land back on Earth post-launch. After releasing its payload, the first stage returns using steerable grid fins and deployable landing legs. This development pioneered a new era of reusable launch systems.

During flight:

• The first stage carries the vehicle up to 80 km (50 miles), where stage separation occurs.
• Instead of turning back immediately, the stage continues briefly due to momentum, while the second stage proceeds with the mission.
• Cold gas thrusters perform a 180° flip, aligning the booster’s base toward Earth.

As the booster re-enters the atmosphere, drag slows it down. Upon reaching lower altitudes, grid fins guide its descent toward the landing pad. One of the engines reignites to reduce speed further, and landing legs deploy for a soft, vertical landing.

Following Falcon 9’s success, SpaceX developed Falcon Heavy, which uses three boosters, and is currently working on Starship—the world’s first fully reusable rocket, intended for deep space missions, including to Mars.