What are the Space Launch System and Orion, and why are they important?
The Space Launch System and Orion are two of the core components of NASA’s plans to return astronauts to the moon’s surface in the coming years. Getting there requires a rocket powerful enough to push a large spacecraft from low Earth orbit toward the moon, some 240,000 miles away. Orion is a capsule designed to carry astronauts on space trips of up to a few weeks.
What problems arose during the dress rehearsal?
In mid-March, NASA rolled the SLS rocket to the launch pad for the first time. In early April, it attempted a “wet dress rehearsal” of countdowns, including loading more than 700,000 gallons of liquid hydrogen and liquid oxygen rockets. However, technical issues, including a hydrogen leak during three rehearsals, cut the countdown short.
NASA then rolled the rocket back to the Vehicle Assembly Building to make repairs. In June, the rocket returned to the launch pad for another attempt at the wet dress rehearsal. That attempt, on June 20, encountered several hydrogen leaks in a fuel line connector to the rocket’s booster stage. However, the propellant tanks were fully filled for the first time and inspectors were able to continue the rehearsal until the countdown ended with 29 seconds left. Originally the intention was to stop the countdown in just under 10 seconds, when the engines would start for an actual launch.
Despite the leak, NASA officials decided all critical systems had been adequately tested and declared the test a success. The missile returned to the Vehicle Assembly Building for final preparations, including the installation of the flight closure system, which would inflate the missile in case something went wrong during launch and eliminate the possibility of a crash in a populated area.
The flight-termination system batteries, installed on Aug. 11, normally only last 20 days, but the portion of the US space force that oversees launches from Florida granted NASA a waiver extending the period to 25 days. This allows for the August 29 launch date, as well as backup capabilities on September 2 and 5.
NASA hopes to fix the hydrogen leak, but won’t know for sure until its August 29 countdown, when the propellant gas pipeline has cooled to ultra-cold temperatures, something that can’t be tested at the Vehicle Assembly Building.