As part of the Artemis lunar exploration program, NASA plans to return astronauts to the Moon and use that experience to inform future human exploration of Mars. To safely and comfortably explore for days at a time on the surface of these celestial bodies, astronauts need suitable equipment and places to live. Almost 20 years of human habitation aboard the International Space Station and a growing body of research conducted there are contributing important insights into how to meet these needs for future lunar explorers.
An orbiting Gateway
As a first step toward sustained human presence on the Moon, NASA is building an outpost in lunar orbit, known as Gateway. This spaceship will provide access to more of the lunar surface than ever before and serve as home base for astronaut expeditions on the Moon. Its capabilities for science, more autonomous exploration, and commercial and international partnerships all are influenced by and build on the experiences of the space station. Where the space station has provided opportunity for long-duration human spaceflight, Gateway takes the next step, into the deep space environment.
Home, home on the Moon
It will not be practical for astronauts on the Moon to spend extended time in a tent or the cramped quarters of a landing capsule like those used by Apollo astronauts. Scientists and engineers have used the space station to learn more about how we might one day create extraterrestrial habitats and make explorers comfortable in them.
For example, the space station enabled testing of BEAM, a prototype of a compact, lightweight expandable habitat that takes up minimal space at launch. After deployment in space or on the Moon, this type of habitat provides protection from solar and cosmic radiation, debris and other contaminants. Crew members expanded BEAM in May 2016 and have been in it dozens of times, collecting radiation, microbial air and surface samples that are returned to Earth for analysis.
Another technology studied on the space station, 3D printing, could address logistical constraints of future space exploration. Experiments on the space station have shown that 3D printers work normally in microgravity and demonstrated use of a refabricator, a 3D printer that uses recycled waste plastic materials. Eventually, astronauts could use 3D printing to make their own spare parts, tools and materials on demand. Missions to Mars will not have the capability for resupply or be able to carry many spare parts. Repurposing materials and printing spares could help solve these problems. The Refabricator offers one way to deal with the issue of trash on long space missions.
If the suit fits
Spacecraft and habitats have life support systems to provide astronauts with oxygen, safe temperatures and protection from radiation. To work outside of these environments on, say, the Moon, requires wearing a spacesuit. Suits need to serve as individual, mobile life support systems, as well as feel comfortable and fit correctly.
Research on the space station tested a new thermal control technology that uses water to maintain appropriate temperatures in spacesuits. The Spacesuit Evaporation Rejection Flight Experiment investigation also evaluates this technology’s effect on contamination and corrosion of some materials used in spacesuits.
The human body changes in space and a suit that fits on Earth may not fit once its wearer is on the Moon. Research on the space station that collected comprehensive body measurements from astronauts before, during and after flight could help address the issue of suit sizing.
Space station research contributes to NASA’s design of a new suit specifically for Artemis missions, the Exploration Extravehicular Mobility Unit (xEMU). It also provides a way to test and refine this suit and its features.
Beyond the suit
The 227 spacewalks taken from the space station have provided useful experience for future spacewalk planning and preparation.
Teams map out specific tasks step by step for each spacewalk, typically working to fit them within about six hours. Spacewalks sometimes run longer — the longest one lasted eight hours and 56 minutes – and these experiences help teams refine expectations for how long various tasks take in space.
A recent set of spacewalks set out to repair an instrument not originally designed for servicing in space, which meant it had no handrails or foot restraints and did not accommodate the usual spacewalk tools. The spacewalks required four years of planning but accomplished more than successfully repairing the instrument. The process of creating and testing special tools and procedures for the effort is contributing to better planning for tomorrow’s spacewalks on Moon and Mars missions. Furthermore, astronauts learned to cut and reconnect fluid lines on a spacewalk, which had never been done before and may be a valuable skill on missions several days or months from Earth.
Meteors are fragments of rock or minerals created by the disintegration of comets or asteroids orbiting the sun. Small fragments burn up completely or partially in Earth’s atmosphere, but the Moon has no atmosphere to protect it – or astronauts.
NASA’s Lunar Reconnaissance Orbiter (LRO), launched in 2009 to map the lunar surface, revealed that the Moon experiences a heavier bombardment by small meteoroids than models had predicted. That means a lunar base must be sturdier than previously thought. While a direct hit is unlikely, the intense rain of secondary debris thrown out by a nearby impact poses a risk.
Whipple shields, already in use on crewed modules of the space station, are one possible type of protection. The shields consist of a thin outer layer and a thicker rear layer, with a small space between the two. The outer layer breaks upon impact, disintegrating the projectile and spreading the force over a larger area of the inner wall of the spacecraft. NASA and ESA (European Space Agency) have conducted research about how to make the systems more effective to support better protection of lunar facilities.