Why SpaceX 'catching' Starship booster with robotic arms is significant

Contact Counsellor

Last Updated16/10/2024

A pair of giant robotic arms caught the more than 70-metre-long first stage booster of SpaceX’s Starship on Sunday, bringing Elon Musk’s company a step closer to its goal of building a fully and rapidly reusable rocket system.

On Sunday, SpaceX achieved another milestone in its quest to revolutionize space travel by successfully catching the first stage booster of its Starship rocket system with two giant robotic arms. This brings Elon Musk’s company closer to creating a fully and rapidly reusable rocket, a key innovation for reducing the cost of space exploration and expanding humanity’s reach beyond Earth.

The Starship rocket system is a two-stage heavy-lift vehicle comprising:
- Super Heavy (the first-stage booster)
- The Starship spacecraft (the upper stage)
Standing at nearly 120 meters tall, Starship is the largest rocket ever built, surpassing NASA's iconic Saturn V, which took astronauts to the Moon. Starship is designed to carry crew and cargo to Earth orbit, the Moon, Mars, and beyond, aiming to revolutionize the future of space travel with its reusability.

SpaceX's mission on Sunday marked a significant step in its reusable rocket ambitions. The Super Heavy booster, equipped with 33 methane-burning Raptor engines, lifted off from Starbase, Texas. After launch, the booster detached from the Starship spacecraft, flipped, and used 13 Raptors to descend back to Earth at high speed. Instead of splashing into the ocean, SpaceX aimed to land it safely back at the launch site.
The highlight of the mission was the robotic arms, dubbed "Mechazilla," catching the descending booster mid-air, avoiding the need for landing legs or ocean recovery. Meanwhile, the Starship spacecraft completed one orbit around Earth before a controlled splashdown in the Indian Ocean.

Most current rocket systems are expendable, meaning they are used only once, making space missions expensive and time-consuming. SpaceX aims to change this by making both the booster and the spacecraft fully reusable, allowing for rapid turnaround times between launches. Catching the Super Heavy booster is a critical step in this vision, as it could enable faster, more frequent, and lower-cost space missions.
Elon Musk envisions a future where Mechazilla could quickly re-stack the Starship spacecraft on top of the landed booster, enabling a relaunch within as little as 30 minutes.

Starship is central to SpaceX's future space exploration ambitions. It is a key part of NASA's Artemis III mission, scheduled to return astronauts to the Moon by 2026, using the Starship HLS (Human Landing System). SpaceX has secured contracts worth around $4 billion to make this mission possible.
In the long term, Starship is designed to take humanity to Mars and beyond. SpaceX aims to use the rocket to carry both cargo and crew to the Red Planet, helping to establish a permanent human presence there.

While reusable rockets have been tested before, they pose challenges. For example, NASA’s Space Shuttle program (1972–2011) used partially reusable spacecraft, but maintaining and refurbishing the shuttles turned out to be more expensive than launching expendable rockets. SpaceX hopes to avoid similar pitfalls by refining its reusable systems to be cheaper and more efficient than their predecessors.