With Artemis II — the first crewed flight of SLS and Orion — four astronauts will travel to the lunar environment in 2024. The Artemis II crew will have an approximate 10-day mission where they will set a record for the farthest human travel (4,600 miles) beyond the far side of the Moon in a hybrid free-return trajectory.

The spacecraft will make two orbits around Earth before committing to the trip to the Moon. After reaching high Earth orbit (HEO), Orion will separate from the interim cryogenic propulsion stage (ICPS) and the expended stage will have one final use before it is disposed through Earth’s atmosphere: the crew will use it as a target for a proximity operations demonstration. In this demonstration, the astronauts will pilot Orion’s flight path and orientation in manual mode.

The demonstration will provide performance data and operational experience that cannot be readily gained on the ground in preparation for critical rendezvous, proximity operations, docking, and undocking operations beginning on Artemis III.

Checking Critical Systems

While still close to Earth, the crew will assess the performance of the life support systems necessary to generate breathable air and remove the carbon dioxide and water vapor produced when the astronauts breathe, talk, or exercise. The long orbital period around Earth provides an opportunity to test the systems during exercise periods, where the crew’s metabolic rate is the highest, and a sleep period, where the crew’s metabolic rate is the lowest.

A change between the suit mode and cabin mode in the life support system, as well as performance of the system during exercise and sleep periods, will confirm the full range of life support system capabilities and ensure readiness for the lunar flyby portion of the mission. Orion will also check out the communication and navigation systems to confirm they are ready for the trip to the Moon.

While still in elliptical orbit around Earth, Orion will briefly fly beyond the range of GPS satellites to allow an early checkout of NASA’s Deep Space Network communication and navigation capabilities. When Orion travels out to and around the Moon, mission control will depend on the Deep Space Network to communicate with the astronauts, send imagery to Earth, and command the spacecraft.

On the remainder of the trip, astronauts will continue to evaluate the spacecraft’s systems including demonstrating Earth departure and return operations and practicing emergency procedures, among other activities.

Protecting the Crew

While Orion is designed with systems and materials to keep the crew safe during their journey, leaving the protection of Earth’s magnetosphere exposes astronauts to a radiation environment in space that scientists and engineers at Johnson Space Center in Houston are working hard to protect against.

To limit risks, the team is developing a way to make use of the mass onboard the spacecraft to protect the crew and has conducted evaluations to test procedures for getting astronauts into their protective environment as quickly as possible.

The goal is to limit the risk of radiation exposure over an astronaut’s lifetime. Orion will be equipped with a radiation-sensing instrument integrated into the vehicle called the Hybrid Electronic Radiation Assessor (HERA) to provide a warning if crewmembers need to take shelter in the case of a radiation event such as a solar flare.

In such an event, astronauts will position themselves in the central part of the crew module largely reserved for storing items they’ll need during flight and create a shelter using the stowage bags on board. The method protects the crew by increasing mass directly surrounding them and therefore making a denser environment that solar particles would have to travel through, while not adding mass to the crew module itself.

If the warning were to sound, the crew would create the shelter within an hour and in some cases would need to stay inside for as long as 24 hours. Using the stowage bags onboard that will contain supplies, food, and water — in combination with Orion’s seats — astronauts can construct the shelter by strategically placing denser bags in areas of the vehicle with less radiation-protecting materials. For example, the bottom of Orion — where the heat shield and service module are attached — will provide more shielding than other areas, and stowage bags can be used for parts of the spacecraft’s interior with less shielding.

The evaluation also includes assessing ways to tie down the stowage bags, where to locate tubing to provide air to the shelter, and the best ways to get in and out of it.

NASA’s Orion Crew Survival System spacesuit is designed for a custom fit and will protect astronauts during launch, reentry, and emergency situations during Artemis missions. (NASA/Joel Kowsky)

The Orion Suit

When astronauts are hours away from launching on Artemis missions, they’ll don an orange spacesuit called the Orion Crew Survival System (OCSS). It is designed for a custom fit and is equipped with safety and mobility features to help protect astronauts on launch day, in emergency situations, in high-risk parts of missions near the Moon, and during the high-speed return to Earth.

Many missions require two space-suits: one worn outside a spacecraft during spacewalks that is designed as a self-contained personal spaceship, and another worn inside the spacecraft during high-risk parts of a mission such as inside Orion during launch and reentry through Earth’s atmosphere. NASA is building both for Artemis missions. NASA has re-engineered elements of the crew survival suit worn on the space shuttle to enhance range of motion and improve safety for the astronauts who will wear it to get to the Moon and back to Earth.

The Orion suit, sometimes called a flight suit or a launch and entry suit, has been enhanced from head to toe with improvements to the suit astronauts wore on shuttle missions.

Features on the helmet, for example, allow for improved comfort and function. The helmet is lighter, stronger, comes in more than one size, helps reduce noise, and is easier to connect to the communications system needed to talk to other crewmembers and Mission Control.

The outer cover layer — which is orange to make crewmembers easily recognizable in the ocean should they ever need to exit Orion without the assistance of recovery personnel — includes shoulder enhancements for better reach and is fire-resistant. The suit is a pressure garment that includes a restraint layer to control the shape and ease astronauts’ movements. A re-engineered zipper also allows astronauts to quickly put the suit on and has increased strength.

New adaptable interfaces supply air and remove exhaled carbon dioxide. The suit has improved thermal management that will help keep astronauts cool and dry. A liquid cooling garment worn underneath the suit — a bit like thermal underwear with embedded cooling tubes — was revamped to be more breathable and easier to build.

While shuttle-era spacesuits came in off-the-shelf sizes like small, medium, and large, the Orion suits will be custom fit for each crewmember and accommodate astronauts of all sizes. The suits’ gloves, the part of a spacesuit that receives the most wear and tear, are more durable and touchscreen compatible, and improvements to the boots provide protection in the case of fire, fit better, and help an astronaut move more nimbly.

Even though it’s primarily designed for launch and reentry, the Orion suit can keep astronauts alive if Orion were to lose cabin pressure during the journey out to the Moon or on the way back home. Astronauts could survive inside the suit for up to six days as they make their way back to Earth.

The suits are also equipped with a suite of survival gear in the event they must exit Orion after splashdown before recovery personnel arrive. Each suit will carry its own life preserver that contains a personal locator beacon, a rescue knife, and a signaling kit with a mirror, strobe light, flashlight, whistle, and light sticks.

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This article first appeared in the November, 2021 issue of Tech Briefs Magazine.

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