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 get astronauts to the lunar surface in the years to come. Getting there will require a rocket powerful enough to launch a large spacecraft from low Earth orbit to the Moon, some 240,000 miles away. Orion is a capsule designed to carry astronauts on space voyages that can last up to a few weeks.
What problems did you encounter during the dress rehearsal?
NASA rolled the SLS rocket to the launch pad for the first time in mid-March. In early April, it attempted a “wet dress rehearsal” of countdown procedures, including loading more than 700,000 gallons of liquid hydrogen and liquid oxygen rocket propellants. However, technical glitches, including a hydrogen leak on three rehearsal attempts, shortened the countdown.
NASA then rolled the rocket back to the Vehicle Assembly Building for repairs. In June, the rocket returned to the launch pad for another attempt at the wet dress rehearsal. That test on June 20 uncovered another hydrogen leak in a fuel line connector to the rocket’s booster stage. However, the fuel tanks were fully filled for the first time, and the controllers were allowed to continue the rehearsal until the countdown ended with 29 seconds remaining. Originally the countdown was supposed to stop at just under 10 seconds when the engines were about to start for an actual launch.
Despite the leak, NASA officials decided that all critical systems had been adequately tested and declared the test a success. The rocket once again drove back to the Vehicle Assembly Building for final preparations, including installing the flight termination system that would blow up the rocket if anything went wrong during launch and eliminating the possibility of it crashing into a populated area would.
The flight termination system batteries installed on Aug. 11 are normally only rated to last 20 days, but the portion of the United States Space Force that oversees launches from Florida granted NASA a waiver extending the period to 25 days . This allows for the August 29 start date as well as backup opportunities on September 2 and 5.
NASA hopes it has fixed the hydrogen leak, but won’t know for sure until the August 29 countdown, when the propellant line has cooled to ultra-cold temperatures, which cannot be tested in the Vehicle Assembly Building.