For astronauts to get to the moon, they need a big rocket, and the Space Launch System is that rocket — the most powerful one since Saturn V took NASA astronauts to the moon in the 1960s and 1970s. The one waiting on the pad to launch on Monday is 322 feet high, and will weigh 5.5 million pounds when filled with propellants.
It will be able to lift more than 200,000 pounds to low-Earth orbit and send nearly 60,000 pounds of payload to the moon. Its cargo on Monday is Orion, a capsule that will be uncrewed for this flight but can carry four astronauts.
The rocket, known as S.L.S., resembles a stretched external tank used by the retired space shuttles, and the side boosters that help it get to space look a lot like engines the shuttles used.
This is by design: To simplify development of its new moon rocket, NASA reused much of the 1970s space shuttle technology. The rocket’s central stage is the same 27.6-foot diameter as the shuttle’s external tank, and it is covered with the same orange insulation.
The four engines in the core stage are the same as the space shuttle main engines. The first three Artemis missions actually use engines that were pulled from the old shuttles and refurbished. Because none of the S.L.S. rockets will be used more than once, NASA will run out of old shuttle engines after Artemis IV. New engines will be needed for Artemis V and later.
The side boosters are longer versions of those that were used for space shuttle flights. During the space shuttle era, NASA recovered and reused similar boosters. But for the Space Launch System, which will launch only about once a year, the agency decided it would be easier and more economical to let the boosters sink into the ocean and use new ones for each flight.
The second stage of the S.L.S., which will propel the Orion capsule on a path to the moon once it gets to low-Earth orbit, is essentially a modification of the one used for another rocket called Delta IV. A new upgraded second stage will be used for Artemis IV, making the rocket even more powerful.
The Orion spacecraft
A diagram showing the different components of the Orion spacecraft.
CREW module
Can hold four people
launch abort system
Can carry the crew module to safety if there is an emergency during launch
service module
Provides power and propulsion to the crew module
launch
abort system
Can carry the crew module to safety if there is an emergency during launch
CREW module
Can hold four people
service module
Provides power and propulsion to the crew module
CREW module
Can hold four people
launch abort system
Can carry the crew module to safety if there is an emergency during launch
service module
Provides power and propulsion to the crew module
Source: NASA
Development of the Orion crew capsule started in 2006 as part of Constellation, an earlier moon program started under President George W. Bush. Costs for Constellation spiraled upward, and the Obama administration attempted to cancel it entirely in 2010.
However, Congress rebelled against that. That led to a revival of Orion and Ares V, the heavy lift rocket that was planned for Constellation, turned into the Space Launch System.
The Orion capsule is designed for trips that last multiple weeks in deep space beyond low-earth orbit. That means that the vehicle, while bigger than the Crew Dragon capsule that carries astronauts to the space station, has a bit less space on the inside to make room for more robust life support systems.
