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The Artemis I mega lunar rocket is ready for another test before its next launch attempt to travel around the moon and back.
The launch director gave the “go” to start tanking for the Artemis I cryogenic demonstration test at 7:30 a.m. ET Wednesday, and NASA will share live coverage on its website. If all goes well, the team expects the test to be completed by 3 p.m. ET.
The Space Launch System rocket and Orion spacecraft continue to sit on the launch pad at Kennedy Space Center in Florida.
Since the Artemis I uncrewed mission’s second clean launch attempt on September 3, engineers have replaced two seals on an interface for the liquid hydrogen fuel line between the rocket and the mobile launch vehicle, according to NASA officials. These seals were associated with a major hydrogen leak that led to the launch attempt being scrubbed.
When engineers replaced the seal on an 8-inch (20 centimeter) quick-disconnect line for hydrogen, they found an indentation, Artemis mission manager Mike Sarafin told a news conference in NASA on Monday.
Indentation was less than 0.01 inch (0.3 mm), but it allows pressurized gas to escape, which can be very dangerous considering the flammability of hydrogen when it encounters air. The team believes the dent is associated with the leak, but test results may confirm this.
The purpose of the cryogenic demonstration is to test the seals and use updated, “softer and smoother” loading procedures of the supercold propellant, which the rocket would experience on launch day.
Unlike wetsuit rehearsals, previous Artemis I tests that simulated every step leading up to launch, the cryo test focuses on a very specific aspect of the countdown: the loading of supercold liquid oxygen and liquid hydrogen into the central stage and the upper stage of the rocket.
The Orion spacecraft and rocket boosters will remain unpowered during the test, and the team does not intend to enter the terminal countdown, or the last 10 minutes that occur in the countdown to the launch, said Jeremy Parsons, deputy director of NASA’s Exploration Ground Systems program. at the Kennedy Space Center.
The smoother and gentler loading procedure is to minimize the pressure spikes and thermal spikes seen in previous launch attempts. To achieve this, the team will slowly build pressure on the liquid hydrogen storage tank. The slower procedure is estimated to add no more than 30 minutes to the process, Parsons said.
“It’s going to be a very slow, steady ramp,” Parsons said. “So (we’re) really trying to slowly introduce some of these thermal differences and reduce the thermal and pressure shocks.”
Liquid oxygen is relatively dense, about the density of water, and it is pumped into the rocket. Meanwhile, the hydrogen is very light, so it’s moved using pressure rather than being pumped, said Tom Whitmeyer, deputy associate administrator for NASA’s Joint Exploration Systems Development.
The new loading operations will use a slower pressure rate with more gradual temperature changes, Whitmeyer said.
The test will also include an engine purge, which cools the engines for launch. The mission team scrubbed Artemis I’s first launch attempt on August 29, largely due to an issue with a faulty sensor that occurred during this hemorrhage.
After the liquid oxygen and liquid hydrogen reach the replenishment phase – because part of the super cold propellant is boiling – the team will perform a pre-pressurization test.
“The test will bring the liquid hydrogen tank to the pressure level it will experience just before launch while engineers will calibrate engine conditioning parameters to a higher flow rate, as will be done during terminal metering,” according to NASA officials. “Running the pressurization test during the demo will allow teams to dial in the necessary parameters and validate timelines before launch day, reducing schedule risk during the launch countdown.”
If the cryogenic test goes well, the next launch attempt could be Tuesday, September 27, with a 70-minute window that opens at 11:37 a.m. ET. Mission leaders will meet to discuss test results on September 25 to assess the potential launch date.
Team Artemis receives daily briefings on Hurricane Fiona in case it impacts whether or not to bring the rocket stack back to the Vehicle Assembly Building, a process that can take three days.
If Artemis I is launched on September 27, it will complete a 39-day mission and return to Earth on November 5. Another backup launch date is possible on October 2. Although these launch dates are recommended by NASA, the team ultimately depends on a decision by the US Space Force, which should issue a waiver for the launch.
The US Space Force, a branch of the military, still oversees all rocket launches from the east coast of the United States, including the NASA launch site in Florida, and this area is known as Eastern Range.
Range managers are responsible for ensuring that there is no risk to persons or property during any launch attempt.
The Artemis team continues to have “productive and collaborative” discussions with the Eastern Channel, and NASA is sharing additional detailed information requested by Space Force for review.
“We’ll go when we’re ready,” Sarafin said. “But in terms of the reward of flying this flight, we said from the start that this is the first in a series of increasingly complex missions, and that this is a deliberate rocket stress test.”
The inaugural mission of the Artemis program will launch a phase of NASA space exploration that aims to land diverse crews of astronauts in previously unexplored regions of the moon – on the Artemis II and Artemis III missions, scheduled for 2024 and 2025, respectively – and possibly delivering crewed missions to Mars.
The agency released an updated version of its “Moon to Mars” goals on Tuesday, which lays out a blueprint for exploring the solar system.
“We are helping to manage humanity’s global movement into deep space,” Jim Free, NASA associate administrator for the Exploration Systems Development Missions Directorate, said in a statement.
“The goals will help ensure that a long-term strategy for solar system exploration can maintain constancy of purpose and weather political and funding changes.”
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