With SpaceX now launching its reusable Falcon 9 rocket several times a week, the American company has quickly become a giant in global spaceflight. It’s a far cry from the days of the American Space Shuttle, which launched an average of 4.5 times per year during its lifespan between 1981 and 2011. People sometimes use the terms “rocket” and “space shuttle” interchangeably, but there is an important difference between the two.
A rocket is the launch vehicle that carries a crew or payload into space, while the Space Shuttle was a specific reusable orbiter that used rockets to go into orbit before returning to land like an airplane. Simply put, the rocket is the launch system, while the space shuttle is the vehicle that carries it. If you watch a space shuttle launch, you can clearly see its two side rockets propelling the vehicle into space. After a few minutes, with the space shuttle well underway, these two side thrusters detach and fall into the ocean before being recovered for reuse.
Meanwhile, the Space Shuttle’s three integrated rocket engines continue to propel the vehicle into orbit. Similarly, launching a Falcon 9 involves the first stage rocket booster propelling the upper stage, including the crew or payload, into space. Like the Space Shuttle, the booster detaches from the rest of the vehicle, but instead of being recovered from the ocean, it lands upright on Earth.
Break down the differences
Modern rockets like SpaceX’s Falcon 9 include a first stage and an upper stage supporting the crew capsule or payload, which sits atop the vehicle. The Space Shuttle had three main components: two side rocket boosters that fell and were later recovered, an external fuel tank that was discarded, and the airplane-shaped section for the crew. The shuttle was launched in the same way as conventional rockets, using rocket engines to travel upward to escape Earth’s gravity.
But differences appear from the start of a mission. The shuttle, for example, jettisoned its two rocket boosters and fuel tank before reaching orbit, while the Falcon 9’s first stage returns to Earth for reuse, and the upper stage takes the crew capsule into orbit before separating from it. Returning home, the shuttle re-entered Earth’s atmosphere at high speed, the lower heat shield resisting the extreme temperatures. It then glided like an airplane towards its destination, landing on a runway before deploying brakes and a parachute system to stop it.
Before the Falcon 9, the first stage of an orbital rocket fell into the ocean and was not recovered. SpaceX developed a way to land and reuse its first stage booster, allowing it to significantly reduce launch costs. After deploying a spacecraft or payload, a Falcon 9’s first stage performs a series of burns that allow it to land upright on a barge waiting near the launch pad — usually about eight minutes after liftoff. The Falcon 9 is then ready to be relaunched. Rockets are general-purpose launch vehicles, while the Space Shuttle was primarily a crewed spacecraft for orbital operations, including ISS missions as well as satellite deployments and maintenance activities.
The space shuttle is gone, but the rockets continue to fly
After 30 years of operation, the US space agency’s final Space Shuttle mission took place in 2011. Becoming one of NASA’s most expensive space projects ever, the agency found the system too expensive to maintain. Safety was also a constant concern after two tragic accidents – Challenger in 1986 and Columbia in 2003 – in which all crew members perished.
To reduce expenses, NASA encouraged private companies to begin making commercial rockets to carry crews into orbit in separate capsules – the same way the space agency sent astronauts into orbit under the Gemini and Apollo programs in the 1960s and 1970s. NASA also developed a new rocket called the SLS (Space Launch System) and the Orion spacecraft for crewed missions to the Moon. SpaceX, founded by billionaire entrepreneur Elon Musk in 2002, developed the Falcon 9 rocket and its reusable first stage booster.
Nine years after the end of the Space Shuttle program, NASA and SpaceX used the Falcon 9 and Crew Dragon capsule to resume human spaceflight missions from American soil in 2020, sending two astronauts to the International Space Station and returning them safely home. The historic mission marked a new era for American crewed spaceflight and showed that a reusable rocket paired with a separate capsule could make spaceflight more sustainable than the Space Shuttle’s all-in-one design ever could.
