Weeks after rolling out the Space Launch System on the pad, Nasa is set to resume the critical test for the world’s most powerful rocket to test its feasibility for a mission to the Moon.
Engineers and the Artemis team will resume the Wet Dress Rehearsals for the system with a modified test, primarily focused on tanking the core stage and minimal propellant operations on the interim cryogenic propulsion stage (ICPS) with the ground systems at Kennedy.
The tanking operation, which will see the rocket’s tanks being loaded with propellants, will begin on April 14. Over 7,00,000 gallons of cryogenic, or super cold, propellants including liquid hydrogen and liquid oxygen will be loaded into the rocket at the launch pad on the mobile launcher.
Earlier, the test was halted after engineers identified a helium check valve that was not functioning as expected, requiring changes to ensure the safety of the flight hardware. A check valve is a type of valve that allows liquid or gas to flow in a particular direction and prevents backflow. The helium check valve is about three inches long and prevents the helium from flowing back out of the rocket.
Nasa said that Helium is used for several different operations, including purging the engine or clearing the lines, prior to loading propellants during tanking, as well as draining propellants.
“Wet dress rehearsal is an opportunity to refine the countdown procedures and validate critical models and software interfaces. The modified test will enable engineers to achieve the test objectives critical to launching success,” Nasa said in a blog update.
With the faults now fixed, once the tanking operation is complete, teams will power up Orion and the Space Launch System core stage, charge the core stage battery, and prepare the four RS-25 engines, which will not be lit during the test.
During the test, the Artemis team aims to demonstrate tests on the cryogenic systems and an approximately three-minute hold inside the terminal count, which would not normally occur on launch day.
Once the launch controllers reach the point just before the rocket’s RS-25 engines will ignite on launch day, they will recycle back to the T-10 minute point, and then resume the countdown once more after a hold.
As far as the weather is concerned, meteorologists predict favorable weather for propellant loading operations. “Weather constraints stipulate there must be less than a 20 per cent chance of lightning within five nautical miles of the pad during the first hour of tanking. Winds also must not be above 37.5 knots and the temperature cannot be below 41 degrees Fahrenheit,” Nasa said.