Leonard David's INSIDE OUTER SPACE

Completion of Avcoat block bonding on Artemis II heat shield. Image credit: NASA/Isaac Watson

NASA’s Artemis I/Orion capsule re-entry and splashdown are slated for the weekend – and it’s going to be a hot and telling time contrasted to old Apollo town technology.

Re-entering the atmosphere for its final descent into the Pacific Ocean near San Diego on December 11, the craft faces nearly 5,000 degrees Fahrenheit temperatures, about half as hot at the Sun, as it plunges to Earth.

Courtesy: Lockheed Martin

Building process

To be sure, 20^th century Apollo heat shield technology was the basis for the 21^st century Orion’s heat shield, but the building process was altered.

Instead of having technicians fill 300,000 honeycomb cells individually with ablative material, then heat-cure the material and machine it to the proper shape, now Avcoat blocks are used. There are fewer than 200 of them that are pre-machined to fit into their positions and bonded in place on the heat shield’s carbon fiber skin.

Measuring 16.5 feet in diameter, Orion’s new heat shield is the largest of its kind developed for missions that will carry astronauts.

The heat shield was designed by the Lockheed Martin and NASA Orion team and built at the Lockheed Martin manufacturing facility near Denver.

Credit: Lockheed Martin

Skipping stone approach

For the Artemis 1 mission, toss in for good measure, the Orion capsule is using a re-entry maneuver that no human-rated spacecraft steaming back from the Moon has yet attempted – a skip entry.

Orion will streak into the upper Earth atmosphere, then “skip” back out, influenced by atmospheric friction and the lift properties of the capsule. This technique slows the craft for its re-entry and final descent into the Pacific Ocean near San Diego.

Use of skip-type re-entry is not new, but today’s guidance and navigation technology, coupled with computing power, has blossomed far beyond the Apollo age.

This technique was applied in the past, both by several of the former Soviet Union’s non-crewed Zond circumlunar spacecraft missions. China has also made use of this technique within its Chang’e robotic lunar exploration series.

NASA’s Landing and Recovery Team practices bringing a mock Orion capsule into the well deck of the USS Portland ahead of the Artemis I/Orion splashdown slated for Dec. 11.
Image credit: NASA/Kenneth Allen

Recovery teams

What are the pluses of skip entry?

• A more accurate and consistent landing site that does not depend on the date or departure point from the Moon.
• It decreases the g-forces that crew are subjected to during re-entry.
• It also divides the heat of re-entry into two events, thereby enhancing astronaut safety and setting up Orion for a precise entry and water landing.

Teams responsible for recovering Orion after its splashdown are continuing preparations ahead of Orion’s December 11 splashdown off the coast of California.

A mission management team will focus in on the landing site location on December 8.

For an informative Lockheed Martin video on Orion’s re-entry, go to:

https://youtu.be/vWuTJdnxleE