From when the first pressure suits of high-altitude military and experimental aircraft pilots were adapted for applications in Space in the 1960s, the spacesuit as we know it has continued to evolve. Let’s take a look at where things are at with the spacesuits of today and the direction in which they are moving for tomorrow…
Spacesuits are built with a consciousness of that key evolutionary concept ‘adapt to your surroundings or become extinct’, so their main function is to provide the essential elements of Earth’s environment for the occupant as well as protection in the hostile environment of Space for the purpose of keeping them alive.
For spacesuits to be effective they must abide by 2 basic operational principles: to provide a movable pressure vessel around the human body and facilitate normal respiration, heat exchange, hydration, excretions and locomotion, enabling useful work and/or exploration to be done.
So what about the future? Well in terms of suits for future planetary exploration EVA (Extravehicular Activity), new spacesuits are still in the research and development phase. Currently there are many NASA-funded educational and research projects ongoing around the world to aid the Space Administration’s quest of finding the most effective spacesuit prototype for applications such as on the Moon, Mars and eventually asteroids.
An interesting example of this is the NDX-1 Planetary Protype. Built with NASA funds at the spacesuit lab of the University of North Dakota, the ‘North Dakota Experimental-1’ spacesuit system is a pressurized planetary spacesuit demonstrator that operates at 4.5psi. It has already travelled the world, from Arizona to Antarctica, undergoing a variety of tests, the data from which is forwarded to NASA with the hope of better informing the design of its upcoming spacesuits. Similar to an AEMU, this one-of-a-kind model comprises a plexiglass half-dome visor built into a semi-rigid upper torso and soft lower torso. It is composed of 2 layers of carbon fibre separated by a honeycomb of Kevlar compounds which allow the suit to be strong and light at the same time. With the suit itself only weighing 15kg, when combined with the 45kg Portable Life Support System (PLSS) it has a total operational mass of 60kg.
At first glance we might be tempted to think not much has changed in spacesuit development, if our assessment of progression is based on ‘looks’ alone, for in appearance, the latest prototypes resemble many of their ancestors. However, this is not down to any lack of vision by those at the helm of development. Instead with suits such as OCSS and XEMU (in development for the Artemis Program), rather than completely ‘reinventing the wheel’, these new prototypes boldly ‘cherry-pick’ the best and most effective parts from designs of the past, merging these elements with the very latest materials and improved components from the present.
The OCSS or Orion Crew Survival System suit is a new IVA (Intravehicular Activity) fully-pressurised spacesuit that will be worn onboard the Orion spacecraft for launch and re-entry. It will have a closed-loop system and will essentially be an adaption of the conspicuous ‘pumpkin’ orange ACES (Advanced Crew Escape Suit) used by NASA mission crew since the Space Shuttle missions until 2011. The OCSS suit aims to deliver better mobility to the astronauts than its predecessor.
While Artemis’ new XEMU (Exploration Extravehicular Mobility Unit) planetary spacesuits will have many of the same features as the Russian Orlan MKS and American AEMU (Advanced Extravehicular Mobility Unit)- both currently used outside of the ISS, an essential requisite is that they will need to be lighter in weight where possible and more flexible. This is so ensure that on a celestial body (with more than microgravity present) the suits would not be too heavy or cumbersome for the human occupant to move around in. A good example of this is when the Apollo astronauts were moving around on the surface of the Moon in A7L 85kg EVA spacesuits. Basic movements inside these suits were extremely limited, requiring the lunar astronauts to ‘hop’ rather than walk over the lunar terrain and do an energetic ‘pressup’ after falling over while trying to pick something because they couldn’t bend much at their knees or hips!
With careful attention therefore being paid to improving flexibility, mobility and comfort, special joint bearings at the knees, hips, elbows etc. are being introduced with the XEMUs to make the range of motion required for kneeling, collecting rock samples, building habitats etc. less difficult. The next generation of spacesuit boot is currently developing along the line of something akin to a hiking boot with a flexible sole for hard terrain. All these innovations should ensure that from 2024 the male and female Artemis astronauts can actually ‘walk’ rather than hop on the Moon!
With female astronauts particularly in mind, the XEMU’s design also presents optimized mobility side bearings with arm sections/shoulder joints positioned much closer to the body than its predecessors, allowing arms for the first time to rotate above helmet height.
Just as mobile phones and sound systems have become smaller and more compact over time so now has the plumbing and electronics required in the systems of a spacesuit! Where multiple duplicate components for various systems can now be fitted inside the spacesuit for backup should any of the primary components malfunction, this miniaturization should afford the Artemis astronauts an overall increased level of safety on EVAs, potentially enabling longer spacewalks to be undertaken.
With the AEMU’s successor-to-be the internal communications system is also getting something of an upgrade. Astronauts previously found that when on the move, the microphone in the ‘snoopy cap’ worn under their helmets tended to have a rather intermittent connection. Now astronauts’ communications will be supported by multiple embedded voice-activated microphones and a high-speed data transceiver in the upper torso and helmet which will automatically pick up their voice as soon as they speak. The helmet will also contain a HD video system.
AEMU & Orlan MKS spacesuits on the ISS are equipped with caution and warning systems for the occupant that oversee more than 25 parameters. These systems will feature as well in NASA’s new planetary EVA spacesuit.
Another improvement that the xEMU will bring is a second visor layer to protect the main bubble helmet beneath from scratches or other kinds of damage that
could be caused by Space debris. This new quick-swop ‘sacrificial shield’ should save helmets from having to be returned to Earth from the ISS for refurbishment or repair anytime they receive some damage.
For carbon dioxide removal, the new suit will use an alternating ‘swing bed’ scrubber instead of lithium hydroxide cannisters, allowing the poisonous gas to be continually scrubbed for as long as battery power exists. A great advancement, this adaption could potentially extend planetary exploration long beyond the previous 7-8 hour limit. Moreover, the suits are being designed with the allowance for the crew to be able to remain in them for up to 6 days in a worst-case scenario.
This new prototype incorporates the best of the Orlan suit’s ‘step-in’ hatch access method, reducing the very slow ‘Pre-Breath Protocol’ (to avoid decompression sickness) required as astronauts’ bodies slowly and safely adapt to the different atmospheric environment inside the EMU, down to about 5 minutes.
Where some astronauts previously struggled to reach the internal controls inside rigid spacesuits, the XEMU will also optimize the AEMU’s style of inter-connectability, enabling suits to be custom-fitted for each crew member simply by locking on different-sized limb sections. In the same way the suits will be able to be adapted for different tasks or environments simply by changing the fittings or tools.
This exciting next-generation spacesuit will initially serve as the Artemis Program’s upgrade of the Apollo spacesuits and spacesuits used onboard the ISS for use on the lunar surface, to eventually be adapted for use in a Martian environment.
For more information on the history of spacesuits, see: https://armaghplanet.com/14-amazing-spacesuits.html