The National Aeronautics and Space Administration (NASA)'s inspector general said on Tuesday that since NASA selected SpaceX's "Starship" rocket as a lunar lander for astronauts in 2021, the development of the rocket has been delayed for at least two years, and it is expected that more time will be needed to clear the remaining obstacles before landing on the moon. The agency is studying plans to speed up the program.
NASA has been working with a range of companies, most notably Musk's SpaceX and Jeff Bezos' Blue Origin, to launch regular astronaut missions to the moon in its multibillion-dollar Artemis program, aiming to complete the mission before China sends its own astronauts to the lunar surface around 2030.
However, SpaceX has experienced increasing delays in developing Starship. Starship is the program's first lander to carry NASA astronauts to the lunar surface, which has led to the gradual delay of the original target date of 2024 - even though officials at the time were skeptical of the 2024 goal.
One of the most challenging steps on Starship's path to becoming an astronaut-grade lunar lander is that the rocket needs to be refueled in space before heading to the moon, a risky and delicate process that has never been attempted on such a large scale before, the inspector general said in a report Tuesday.
In order for one Starship to send astronauts to the moon, SpaceX first needs to launch 11 other Starships into Earth orbit, which will act as tankers. One of the starships will be a propellant storage depot, requiring more than 10 starships to fill with enough fuel before delivering it to the moon landing starship.
Starship is taller than a 15-story building and is powered by approximately 1,200 metric tons of liquid methane and liquid oxygen, two highly explosive propellants that must be kept cryogenically cold, below -238°F (-150°C).
Low Earth orbit is a politically and commercially important region of space that has seen a surge in satellite traffic. For a company that has routinized the landing of orbital rockets and the launch of astronauts to the International Space Station, docking starships together and carefully transferring ultra-cold propellant at least 10 times in low Earth orbit will be one of the riskiest challenges.
According to the report, NASA officials responsible for overseeing the development of SpaceX’s “Starship” “believe that demonstrating cryogenic propellant transfer is one of the most significant technical challenges facing SpaceX.”
"NASA is tracking one of the biggest risks, which is that some of the cryogenic technologies and capabilities being developed by SpaceX will not be mature enough before the 2028 moon landing," the report said.
SpaceX has launched its Starship system 11 times since 2023 in a series of test flights closely watched by NASA officials.
NASA last month added an additional Artemis test mission and acknowledged the technical challenges its contractors face in the Artemis lunar landing program, in which SpaceX will send humans to the moon in two missions starting in 2028, followed by a similar crewed landing mission by Jeff Bezos' Blue Origin.
The agency has set 2028 as the target date for Starship to land on the moon.