As NASA moves closer to launch of the Artemis II test flight, the agency soon will roll its SLS (Space Launch System) rocket and Orion spacecraft to the launch pad for the first time at the agency’s Kennedy Space Center in Florida to begin final integration, testing, and launch rehearsals.
NASA is targeting no earlier than Saturday, Jan. 17, to begin the multi-hour trek from the Vehicle Assembly Building to Launch Pad 39B. The four-mile journey on the crawler-transporter-2 will take up to 12 hours. Teams are working around the clock to close out all tasks ahead of rollout. However, this target date is subject to change if additional time is needed for technical preparations or weather.
“We are moving closer to Artemis II, with rollout just around the corner,” said Lori Glaze, acting associate administrator for NASA’s Exploration Systems Development Mission Directorate. “We have important steps remaining on our path to launch and crew safety will remain our top priority at every turn, as we near humanity’s return to the Moon.”
As with all new developments of complex systems, engineers have been troubleshooting several items in recent days and weeks. During final checkouts before rollout, technicians found a cable involved in the flight termination system was bent out of specifications. Teams are replacing it and will test the new cable over the weekend. Additionally, a valve associated with Orion’s hatch pressurization exhibited issues leading up to a Dec. 20 countdown demonstration test. On Jan. 5, the team successfully replaced and tested it. Engineers also worked to resolve leaky ground support hardware required to load gaseous oxygen into Orion for breathing air.
Rollout
Once the integrated rocket and spacecraft reach the launch pad, NASA will immediately begin a long checklist of launch pad preparations, including connecting ground support equipment such as electrical lines, fuel environmental control system ducts, and cryogenic propellant feeds. Teams will power up all integrated systems at the pad for the first time to ensure flight hardware components are functioning properly with each other, the mobile launcher, and ground infrastructure systems.
Once complete, the Artemis II astronauts, NASA’s Reid Wiseman, Victor Glover, and Christina Koch, and CSA (Canadian Space Agency) astronaut Jeremy Hansen, will conduct a final walkdown at the pad.
Wet dress rehearsal, tanking
At the end of January, NASA will conduct a wet dress rehearsal, which is a prelaunch test to fuel the rocket. During wet dress, teams demonstrate the ability to load more than 700,000 gallons of cryogenic propellants into the rocket, conduct a launch countdown, and practice safely removing propellant from the rocket without astronauts onsite.
During launch, a closeout crew will be responsible for securing astronauts in Orion and closing its hatches. The closeout crew also will use this rehearsal to practice their procedures safely without astronauts aboard the spacecraft.
The wet dress rehearsal will include several “runs” to demonstrate the launch team’s ability to hold, resume, and recycle to several different times in the final 10 minutes of the countdown, known as terminal count.
The first run will begin approximately 49 hours before launch when launch teams are called to their stations, to 1 minute 30 seconds before launch, followed by a planned three-minute hold and then countdown resumption to 33 seconds before launch – the point at which the rocket’s automatic launch sequencer will control the final seconds of the countdown. Teams then will recycle back to T-10 minutes and hold, then resume down to 30 seconds before launch as part of a second run.
While NASA has integrated lessons learned from Artemis I into the launch countdown procedures, the agency will pause to address any issues during the test or at any other point should technical challenges arise. Engineers will have a close eye on propellant loading of liquid hydrogen and liquid oxygen into the rocket, after challenges encountered with liquid hydrogen loading during Artemis I wet dress rehearsals. Teams also will pay close attention to the effectiveness of recently updated procedures to limit how much gaseous nitrogen accumulates in the space between Orion’s crew module and launch abort system hatches, which could pose an issue for the closeout crew.
Additional wet dress rehearsals may be required to ensure the vehicle is completely checked out and ready for flight.
If needed, NASA may rollback SLS and Orion to the Vehicle Assembly Building for additional work ahead of launch after the wet dress rehearsal.
read more: https://www.nasa.gov/missions/artemis/artemis-2/final-steps-underway-for-nasas-first-crewed-artemis-moon-mission/
