Engineers assess hurricane-damaged insulation ahead of Artemis launch Wednesday – Spaceflight Now
A STORY WRITTEN FOR CBS NEWS & USED WITH PERMISSION
NASA managers have cleared the agency’s leaky Artemis moon rocket to begin another countdown, but engineers must resolve questions about hurricane-damaged insulation before the big booster can be cleared to launch on an unmanned moon shot.
After multiple delays due to hydrogen fuel leaks and other malfunctions, along with a rocket attack from Hurricane Nicole last week, NASA managers met Sunday to review launch preparations and agreed to begin a 47-hour, 10-minute countdown at 1 :54 am EST Monday. The launch is scheduled for Wednesday at 1:04.
But strong winds from Nicole caused a thin strip of sealant-like material known as RTV to break off and separate from the base of the Orion capsule’s protective nose cone on top of the rocket.
The material is used to fill the slight depression where the fairing attaches to the capsule, minimizing aerodynamic heating during ascent. The cladding fits over the Orion capsule and is discarded when the rocket exits the dense lower atmosphere.
“It was an area about 10 feet long (on) the windward side that the storm blew through,” said mission manager Mike Sarafin. “It’s a very, very thin layer of RTV, about two inches or less … in thickness.”
Engineers do not have access to the platform for repairs and must develop a “flight rationale”, i.e. a justification for flying despite the delaminated RTV, in order to proceed with the launch. Managers want to be sure that any additional material that is withdrawn during flight will not affect and damage downstream components.
This issue is reminiscent of the debate following the foam debris incident in October 2002 that damaged the shuttle’s base electronics. In that case, NASA decided to continue flying while engineers developed a fix. Two flights later, another blast of foam fatally damaged the left wing of the shuttle Columbia.
Sarafin said the SLS rocket, which made a test flight without a pilot, is “a fundamentally different vehicle design.”
“The vehicle in this case is bigger and we have to take that into account,” he said. “But in terms of hitting the critical components … the physics is the same, the analysis is very similar, but where the critical components are (is) just fundamentally different.”
In any case, NASA’s mission management team plans to meet again Monday to review the rationale for the flight and determine whether the countdown to launch can continue.
If all goes well, the launch team will begin pumping 750,000 gallons of supercooled liquid oxygen and hydrogen fuel back into the huge rocket’s tanks starting shortly before 4 p.m. Tuesday, using revised “burner, gentler” techniques to control temperatures and minimize sharp spikes in pressure on the rocket. prevent leakage in critical seals.
If any issues arise, engineers will have two hours to resolve them before the launch window closes.
But the weather is 90 percent “full,” and if refueling procedures work as intended, the 1,000-foot-tall Space Launch System rocket’s four main engines and extended solid-fuel boosters should finally roar to life at 1:04 a.m. Wednesday, ushering in a new era in U.S. space flights.
Briefly turning night into day as it climbs to 8.8 million pounds of thrust, the 5.7 million pound SLS will accelerate rapidly as it consumes propellant and loses weight, passing through the speed of sound in less than a minute.
The two boosters, which provide the lion’s share of the rocket’s initial thrust, will burn up and fall off about two minutes and 10 seconds after liftoff. The four hydrogen engines powering the core will shut down six minutes later, placing the Orion capsule and SLS second stage into an initial elliptical orbit.
After raising the lowest point of orbit, a single engine powering the Interim Cryogenic Propulsion Stage, or ICPS, will re-fire about 90 minutes after launch to break out of Earth’s orbit and head for the Moon. The Orion capsule and its service module will separate a few minutes later to continue the rest of the journey on their own.
The goal of the Artemis 1 mission is to send the Orion spacecraft into a circular orbit beyond the Moon in a critical test of the vehicle’s propulsion, navigation and solar systems before returning to Earth for a 5,000-degree reentry and splashdown in the Pacific Ocean west of San Diego.
If the Artemis 1 flight goes well, NASA plans to launch four astronauts atop a second SLS for a lunar shear mission — Artemis 2 — in late 2024, followed by an astronaut landing mission in the 2025-26 timeframe.
But that assumes the Artemis 1 flight goes well. As Jim Free, director of research systems at NASA headquarters, said Friday, “we’ll never get to Artemis 2 if Artemis 1 is not successful.”
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