Engineers evaluate hurricane-damaged insulation before Artemis launches Wednesday - spaceflight now

Engineers evaluate hurricane-damaged insulation before Artemis launches Wednesday – spaceflight now


NASA’s Artemis 1 lunar rocket and Orion spacecraft at Launch Complex 39B. Credit: NASA/Joel Kowsky

NASA executives cleared the agency’s leaky Artemis lunar rocket for the start of a new countdown early Monday, but engineers must resolve questions about hurricane-damaged insulation before the massive booster can be cleared for blast off on an unmanned lunar image.

After several delays due to hydrogen fuel leaks and other glitches, along with the rocket’s nail-biting brush with Hurricane Nicole last week, NASA managers met Sunday to review launch preparations and agreed to start a 47-hour, 10-minute countdown at 1:54 a.m. EST Monday. The launch is scheduled for 01:04 on Wednesday.

But strong winds from Nicole caused a thin strip of caulk-like material known as RTV to delaminate and pull away from the base of the Orion crew capsule’s protective nose cone on top of the rocket.

The material is used to fill in a slight depression where the fairing attaches to the capsule, minimizing aerodynamic heating during ascent. The shroud fits over the Orion capsule and is ejected when the rocket is out of the dense lower atmosphere.

“There was an area that was about 10 feet long (on the windward side) where the storm blew through,” mission manager Mike Sarafin said. “It’s a very, very thin layer of RTV, it’s about two inches or less … in thickness.”

Engineers do not have access to repairs at the plate and must develop a “flight rationale”, that is, a justification for flying despite the delaminated RTV, in order to proceed with the launch. Managers want to ensure that any additional material drifting away in flight will not impact and damage downstream components.

The question recalls a debate following an October 2002 foam debris incident that dented an electronics unit at the base of a shuttle booster. In that case, NASA chose to continue flying while engineers developed a fix. Two flights later, another blast of foam fatally damaged Shuttle Columbia’s left wing.

Sarafin said the SLS rocket, which is making an unmanned test flight, “is a fundamentally different vehicle design.”

“The vehicle in this case is higher, and we have to take that into account,” he said. “But when it comes to hitting 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 flight plan and determine whether the countdown to launch can continue.

A member of NASA’s Artemis ground team is seen inside the white room near the Orion spacecraft hatch during rollback of the Space Launch System lunar rocket to the Vehicle Assembly Building on July 2. The RTV material being analyzed is the thin band surrounding the Orion spacecraft above the NASA “mask” logo. Credit: Stephen Clark/Spaceflight Now

If all goes well, the launch team will begin pumping 750,000 liters of super-cold liquid oxygen and hydrogen fuel back into the huge rocket’s tanks starting just before 4pm Tuesday, using revised “kindler, milder” techniques to control temperatures and minimize sharp pressure jumps to prevent leaks in critical seals.

If any issues arise, the engineers have two hours to resolve them before the launch window closes.

But the weather is 90 percent “go” and if refueling procedures work as intended, the 322-foot-tall Space Launch System rocket’s four shuttle main engines and extended strap-on solid-fuel booster should finally roar to life at 1:04 a.m. Wednesday, ushering in a new era in U.S. spaceflight .

Briefly turning night into day as it climbs away atop 8.8 million pounds of thrust, the 5.7 million pound SLS will rapidly accelerate as it consumes propellant and loses weight, passing through the speed of sound in less than a minute.

The two strap-on boosters, which provide the lion’s share of the rocket’s initial thrust, will burn out and fall away about two minutes and 10 seconds after liftoff. The four hydrogen-powered engines powering the core stage will shut down six minutes later, putting the Orion capsule and SLS second stage into an initial elliptical orbit.

After raising the lowest point in orbit, the single engine powering the Interim Cryogenic Propulsion Stage, or ICPS, will reignite about 90 minutes after liftoff to break out of Earth 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 on a looping orbit beyond the Moon in a critical test of the vehicle’s propulsion, navigation and solar power systems before returning to Earth for a 5,000-degree re-entry 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 rover 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 exploration systems at NASA headquarters, put it Friday, “we’re never going to get to Artemis 2 if Artemis 1 isn’t successful.”

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