A day after the first launch of NASA’s Space Launch System rocket had to be canceled due to an engine cooling problem, mission officials announced they would try again on Saturday.
In the meantime, the engineers will work out the details of a go / no-go plan, just in case they face similar problems as they forced Monday’s scrub.
Saturday’s two-hour launch opportunity opens at 2:17 PM ET (11:17 AM PT) at NASA’s Kennedy Space Center in Florida. If all systems were to work, takeoff would mark the start of NASA’s Artemis 1 mission, an unmanned test flight aimed at setting the stage for sending astronauts to the lunar surface in the mid-1920s.
Some aspects of the countdown will be changed for the attempt on Saturday. For example, mission managers are planning to conduct the engine cooling procedure during an earlier stage of the refueling process. This procedure involves “purging” some of the rocket’s liquid hydrogen to cool the four main engines of the center stage to the desired temperature of 420 degrees below zero Fahrenheit.
When the cooling system was tested in March during a “Green Run” at NASA’s Stennis Space Center in Mississippi, the procedure was successfully conducted at the start of the refueling process. But when the hydrogen purge occurred later in Monday’s countdown, a sensor indicated that one of the engines, engine No. 3, it was not cold enough.
The mission leaders decided to replicate the procedure used in Stennis.
John Honeycutt, head of NASA’s SLS program, suggested that the problem may be with the sensor, rather than the hydrogen purge system itself.
“We understand the physics of how hydrogen behaves,” he told reporters. “The way the sensor behaves is not in line with the physics of the situation.”
Honeycutt said he and his team were working out a plan to verify that the engines are properly refrigerated, based on a wider range of data. He said the team preferred to avoid having to enter the rocket and work directly on the sensor, which may require rolling the rocket back from the launch pad.
“What I intend to do, with the help of the team, is to put ourselves in a situation that gives us the data we need to know that we have cooled the engines properly and are flying, using the data we have accessed. today, ”Honeycutt said.
Engineers will also examine other concerns raised during Monday’s countdown, such as a vent valve leak in the intertank region of the SLS. Launch Director Charlie Blackwell-Thompson said the leak was apparently a consequence of troubleshooting the hydrogen purge system.
Meteorologists say there is a 40% chance of acceptable weather conditions for the launch on Saturday. If time dictates another postponement, Blackwell-Thompson said yet another attempt could be made on Monday, at the end of Labor Day weekend.
For the Artemis 1 mission, the SLS rocket will send an unmanned Orion spacecraft on a test flight that circles the moon and returns to Earth for a splashdown in the Pacific Ocean. NASA’s current plan calls for Artemis 2 to send a manned Orion on a flight around the moon in 2024 and for Artemis 3 to take astronauts to the lunar surface in 2025-2026.