NASA’s big lunar rocket rolls off the launch pad for the third time – and it’s actually set to launch to the moon.
For once, NASA is ahead of schedule.
For a month and a half, the Space Launch System rocket, the most powerful since the Saturn V which took astronauts to the Moon in the 1960s and 1970s, has been parked in a building at the Kennedy Space Center in Florida. There, technicians prepared the rocket for its maiden flight, which could take place in two weeks.
The building’s deployment to the launch pad was scheduled for Thursday, but NASA announced Monday that the move had been brought forward to Tuesday evening. All of this leads to the launch of NASA’s Artemis I mission, an uncrewed test of the giant rocket and Orion spacecraft where astronauts will one day sit.
What happens during the deployment and can I watch it?
It is approximately 4.2 miles from NASA’s massive Vehicle Assembly Building to the launch pad, known as Launch Complex 39B. NASA first used the pad during the Apollo program in the 1960s. The rocket and launch tower will sit on a gigantic vehicle that NASA calls a crawler transporter. It is the same vehicle that carried the Saturn V for the moon landings, but it has been renovated and improved.
The crawler, indeed, crawls. Larger than a baseball diamond and capable of carrying up to 18 million pounds, it will travel at speeds of up to 1 mph down a gravel path to the launch site. The trip will take about 10 hours.
NASA began streaming the deployment Tuesday at 3 p.m. Eastern Time on one of its YouTube channels when the doors to the Vehicle Assembly Building opened. The robot and the rocket could actually start moving around 9 p.m.
What happens next?
Technicians will make final preparations, including connecting power and propellant lines to the rocket and launch tower. Although the deployment is faster, the target time for the launch of Artemis I has not changed: Monday, August 29 at 8:33 a.m. EST.
What are the Space Launch System and Orion, and why are they important?
The Space Launch System and Orion are two of the essential parts of NASA’s plans to bring astronauts back to the surface of the moon in years to come. Getting there requires a rocket powerful enough to push a large spacecraft out of low Earth orbit toward the moon, about 240,000 miles away. Orion is a capsule designed to carry astronauts on space trips that can last up to a few weeks.
What problems arose during the dress rehearsal?
NASA launched the SLS rocket for the first time on the launch pad in mid-March. In early April, he attempted to perform a “wetsuit rehearsal” of countdown procedures, including loading more than 700,000 gallons of liquid hydrogen and liquid oxygen rocket propellants. However, technical issues, including a hydrogen leak during three repeat runs, cut the countdown short.
NASA then took the rocket back to the Vehicle Assembly Building to make repairs. In June, the rocket returned to the launch pad for another wet dress rehearsal attempt. This attempt, on June 20, encountered a different hydrogen leak, in a fuel line connector to the rocket’s booster stage. However, the propellant tanks were fully filled for the first time, and the controllers were able to continue the repeat until the countdown ended with 29 seconds remaining. Originally, the goal was to stop the countdown with just under 10 seconds, when the engines would start for an actual launch.
Despite the leak, NASA officials decided that all critical systems had been sufficiently tested and declared the test a success. The rocket returned to the Vehicle Assembly Building once again for final preparations, including the installation of the Flight Termination System, which would detonate the rocket if there were any problems during launch and eliminate the possibility of s crash in a populated area.
The flight termination system batteries, installed on August 11, normally only last 20 days, but the part of the US Space Force that oversees launches from Florida has granted NASA a waiver that extends the period to 25 days. This allows for the August 29 launch date as well as September 2 and September 5 save opportunities.
NASA hopes to have fixed the hydrogen leak, but it won’t know for sure until the August 29 countdown, when the thruster line will be cooled to ultra-cold temperatures, which cannot be tested in the vehicle assembly building.
This article originally appeared in The New York Times.