During the two day ‘wet dress rehearsal’ of the NASA Artemis mission on Monday, the space agency was forced to call off the test, after an issue with a launcher panel.
This is the last major round of testing for the more than $23 billion Space Launch System (SLS) megarocket, before it goes on an uncrewed trip around the moon.
The dress rehearsal tests all aspects of the system, as well as the Orion capsule that will one day take astronauts back to the moon. They also test launch procedures.
The countdown ended early on Monday after engineers had partially loaded liquid oxygen into the SLS core stage tank, while the megarocket stack was on Complex 39B at the NASA Kennedy Space Center in Florida.
A stuck valve, high on the mobile launcher structure that supports the giant rocket, forced the team to scrub the test – after about half the tank had been filled.
Jim Free, NASA Associate Administrator, Exploration Systems, said: ‘Great progress made in yesterday’s wet dress rehearsal attempt, and I’m proud of the team for continuing to learn as we practice the countdown & fueling for the first time.’
During the two day ‘wet dress rehearsal’ of the NASA Artemis mission on Monday, the space agency was forced to call off the test, after an issue with a launcher panel
The stuck valve was 160ft up on the 322ft rocket, attached to the mobile launcher which acts as a gantry and launch platform for SLS.
The problem was in a panel that controls the valve – meaning it couldn’t be opened if there was a problem with fuelling.
This was the second delay in as many days, after initially being given the go-ahead at 06:45 EDT on Sunday, but called off due to a technical glitch stoping the mobile launcher from being pressurised.
Artemis I is scheduled to launch this summer, taking a ‘crew’ of dummies on a trip around the moon and back to Earth – before a crewed flight in 2024.
NASA says that despite calling off the test, it provided the teams a valuable opportunity for training and to make sure loading procedures were accurate.
This was the first time using new systems at NASA’s Kennedy Space Center, and the team were able to monitor the Artemis I core stage as it was exposed to cryogenic liquids and gather data that will inform updates to propellant loading procedures.
‘After troubleshooting a temperature limit issue for the liquid oxygen, which delayed the countdown by several hours, the team successfully developed a new procedure for loading the liquid oxygen and filled the tank to 50 percent,’ a spokesperson said.
Liquid oxygen is an extremely cold, or cryogenic, propellant that is maintained at minus 297 degrees Fahrenheit.
This is the last major round of testing for the more than $23 billion Space Launch System (SLS) megarocket, before it goes on an uncrewed trip around the moon
During chilldown of the lines in preparation for loading the liquid hydrogen, NASA engineers encountered an issue with a panel on the mobile launcher that controls the core stage vent valve.
Given the time to resolve the issue as teams were nearing the end of their shifts, the launch director made the call to stop the test for the day.
It isn’t clear when NASA will try again, as the team need to investigate the issue, and determine how long it will take to change systems.
The test will be the first full ‘wet dress rehearsal,’ where NASA will conduct a series of final prelaunch tests, including loading the SLS propellant tanks and conducting a launch countdown under similar circumstances to the real launch later in the year.
It provides engineers and officials with a host of information on how the rocket performs, how procedures play out, and informs the decision on when to launch.
The name, wet dress rehearsal, comes from the fact the tests are primarily designed to show that the rocket can be loaded with super-cold liquid propellants.
‘The wet dress rehearsal will be the final major test for the Artemis I mission and will ensure the rocket, spacecraft, ground equipment and launch team are “go” for launch,’ NASA explained.
Atop the massive Space Launch System rocket is the Orion capsule, which will take the first woman and first person of colour to the moon some time after 2025.
NASA expects the official Artemis I launch, the first involving SLS and Orion, to happen anytime from the end of May to mid-July – depending on the rehearsal.
‘We continue to evaluate the May window, but we’re also recognising that there’s a lot of work in front of us,’ said Tom Whitmeyer, NASA Deputy Associate Administrator, with responsibility for exploration systems development.
That work includes analysing the data from the wet dress rehearsal.
‘During the test at the launch pad, engineers will be on duty in the Launch Control Center and in other stations where they will work during the Artemis I launch,’ NASA explained in a blog post about the wet dress rehearsal.
Space Launch System, or SLS, is a launch vehicle that NASA hopes will take its astronauts back to the moon and beyond
NASA expects the official Artemis I launch, the first involving SLS and Orion, to happen anytime from the end of May to mid-July – depending on the rehearsal
‘They will capture as much data as possible on the performance of all the systems that are part of SLS and the Orion spacecraft as well as the Kennedy ground systems.’
After the wet dress rehearsal, the combination of Orion and SLS will stay on Pad 39B for about a month, before rolling back into the hanger for more analysis.
While it is the first mission for the massive Space Launch System rocket engine, it will be the second for the Orion capsule, which was involved in a test flight in December 2014, going to space on a ULA Delta IV Heavy.
When it launches, Orion won’t have any crew on board, despite being able to hold up to four astronauts. Instead, it will carry dummies to the moon and back.
These are designed to replicate human weight and give scientists and engineers and insight into flight performance, without putting humans at risk.
The Artemis I mission will see the Orion spacecraft, the SLS and the ground systems at Kennedy combine to launch the Orion 280,000 miles past Earth around the moon over the course of a three-week mission.
If Artemis I is a success, then NASA will send Artemis II on a trip around the moon, this time with a human crew on board.
The Artemis II mission plans to send four astronauts in the first crewed Orion capsule into a lunar flyby for a maximum of 21 days.
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