NASA Considers Unexpected Orion Heat Shield Performance Ahead of Crew Mission – Ars Technica

It’s been nearly three months since NASA’s Orion spacecraft plunged into the Pacific Ocean after a trip beyond the moon and back. At the time, the space agency said the Artemis I mission had successfully achieved its goals and paved the way for humans to follow suit.

This week, after carefully reviewing data from the Artemis I mission from the outset, space agency officials reiterated that although there were some minor issues with the flight, it has boosted confidence overall. As a result, the chief of NASA’s Human Exploration of Deep Space, Jim Frye, said the agency is targeting “late November” of 2024 for the Artemis II mission.

During this trip, four astronauts – likely to be a Canadian – will spend just over a week in deep space. After checking Orion’s performance in low-Earth orbit, the spacecraft will fly on what’s known as a “free return trajectory” around the Moon, which will bring it as close to the lunar surface as 7,500 km before swinging back.

To much fanfare, NASA expects to name the Artemis II mission crew later this spring. They will be the first humans to fly outside low Earth orbit in more than 50 years, since the end of the Apollo Moon program in December 1972. If NASA is successful with the Artemis II mission, it will pave the way for manned moon landings during the second half of the 2020s.

Orion performance

Perhaps the highlight of the discussion during the press conference was the performance of the Orion heat shield, which protects the spacecraft as it re-enters Earth’s atmosphere at high speed. This is one of the key tests during Artemis I, as vehicles returning from the moon do so at about 40,000 km/h, which is about 30 percent faster than a vehicle returning from low Earth orbit.

“During the inspections, there were more variations across the heat shield than we expected,” said Howard Hu, NASA’s Orion program manager. “Some of the charred material faded differently than what our computer models predicted, and what our ground tests predicted. More of this charred material was released during reentry than we expected.”

A heat shield like the one on Orion, and most other space-returning vehicles, is designed to burn or fade, as it heats up on its journey through the atmosphere. Traction material on the bottom of the spacecraft protects the craft itself and any crew inside from the sweltering conditions outside.

In this case, there is still plenty of margin in traction material on Orion, which means that the unexpected behavior seen in the heat shield poses no danger to the spacecraft. But NASA wants to better model this behavior so that it has a good idea of ​​what to expect during future missions.

“When we have unexpected behavior, we will seek to find a root cause,” Hu said. “I would say we’re going to be very careful and make sure we do our due diligence. Vigilance is very important to us as we fly the crew going forward.”