Just 54 years ago, the first photograph of Mars from a passing spacecraft appeared to show a hazy atmosphere. Now, decades of exploration on the planet itself has shown it to be a world that once had open water — an essential ingredient for life.
Today, engineers and scientists around the country are developing the technologies astronauts will use to live and work on Mars and safely return home.
Building a Mars Spacecraft
When a spacecraft built for humans ventures into deep space, it requires an array of technologies to keep it and a crew inside safe. Both distance and duration demand that spacecraft have systems that can reliably operate far from home, keep astronauts alive in case of emergencies, and still be light enough that a rocket can launch it.
There are five technologies necessary for a spacecraft to survive deep space:
1. Systems to Live and Breathe. As humans travel farther from Earth for longer missions, the systems that keep them alive must be highly reliable while taking up minimal mass and volume. Orion will be equipped with advanced environmental control and life support systems designed for the demands of a deep space mission. A high-tech system being tested aboard the International Space Station will remove carbon dioxide and humidity from inside Orion, which is important to ensure air remains safe for the crew. Water condensation on the vehicle hardware is controlled to prevent water intrusion into sensitive equipment or corrosion on the primary pressure structure. The system also saves volume inside the spacecraft. Without such technology, Orion would have to carry many chemical canisters that would otherwise take up the space of 127 basketballs inside the spacecraft — about 10 percent of crew livable area.
Highly reliable systems are critically important when distant crew will not have the benefit of frequent resupply shipments to bring spare parts from Earth. Even small systems have to function reliably to support life in space, from an automated fire suppression system to exercise equipment that helps astronauts counteract the zero-gravity environment in space that can cause muscle and bone atrophy. Distance from home also demands that Orion have spacesuits capable of keeping astronauts alive for six days in the event of cabin depressurization to support a long trip home.
2. Proper Propulsion. The farther into space a vehicle ventures, the more capable its propulsion systems need to be to maintain its course on the journey and ensure its crew can get home. Orion has a highly capable service module that is the powerhouse for the spacecraft, providing propulsion capabilities that enable Orion to go around the Moon and back on its exploration missions. The service module has 33 engines of various sizes. The main engine will provide major in-space maneuvering capabilities throughout the mission; the other 32 engines are used to steer and control Orion on orbit.
In part due to its propulsion capabilities — including tanks that can hold nearly 2,000 gallons of propellant and a backup for the main engine in tire event of a failure — Orion’s service module is equipped to handle the rigors of travel for missions that are both far and long, and has the ability to bring the crew home in a variety of emergency situations.
3. Holding Off the Heat. The farther a spacecraft travels in space, the more heat it will generate as it returns to Earth. Getting back safely requires technologies that can help a spacecraft endure speeds 30 times the speed of sound and heat twice as hot as molten lava or half as hot as the Sun. Orion’s advanced heat shield, made with a material called AVCOAT, is designed to wear away as it heats up. It is the largest of its kind ever built and will help the spacecraft withstand temperatures around 5,000 °F during re-entry though Earth’s atmosphere. A thermal protection system, paired with thermal controls, will protect Orion during periods of direct sunlight and pitch black darkness while its crews will comfortably enjoy a safe and stable interior temperature of about 77 °F.
4. Radiation Protection. As a spacecraft travels on missions beyond the protection of Earth’s magnetic field, it will be exposed to a harsher radiation environment than in low-Earth orbit, with greater amounts of radiation from charged particles and solar storms that can cause disruptions to critical computers, avionics, and other equipment. Humans exposed to large amounts of radiation can experience both acute and chronic health problems ranging from near-term radiation sickness to the potential of developing cancer in the long term.
Orion is equipped with four identical computers that each are self-checking, plus an entirely different backup computer to ensure it can still send commands in the event of a disruption. It also has a makeshift storm shelter below the main deck of the crew module. In the event of a solar radiation event, NASA has developed plans for crew to create a temporary shelter inside using materials onboard. A variety of radiation sensors will also be onboard to help scientists better understand the radiation environment far away from Earth.
5. Constant Communication and Navigation. Spacecraft venturing far from home go beyond the Global Positioning System (GPS) in space and above communication satellites in Earth orbit. To talk with mission control in Houston, Orion will use all three of NASA’s space communications networks. As it rises from the launch pad and into cislunar space, Orion will switch from the Near Earth Network to the Space Network, and finally to the Deep Space Network that provides communications for some of NASA’s most distant spacecraft.
Orion is also equipped with backup communication and navigation systems to help the spacecraft stay in contact with the ground and orient itself if primary systems fail. The backup navigation system, a relatively new technology called optical navigation, uses a camera to take pictures of the Earth, Moon, and stars and autonomously triangulate Orion’s position from the photos.
Hazards of Life in Space
A human journey to Mars offers an inexhaustible amount of complexities. NASA’s Human Research Program has determined five hazards of human spaceflight; however, these hazards do not stand alone. They can feed off one another and exacerbate! effects on the human body. Various research platforms including the International Space Station, as well as field tests in locations that have physical similarities to Mars, give NASA insight into how the human body and mind might respond during extended trips into space.
1. Radiation. Radiation is not only stealthy but is considered one of the most menacing of the five hazards. Above Earth’s natural protection, radiation exposure increases cancer risk, damages the central nervous system, can alter cognitive function, reduce motor function, and cause behavioral changes. To learn what can happen above low-Earth orbit, NASA studies how radiation affects biological samples on the ISS, which lies just within Earth’s protective magnetic field. Deep space vehicles will have significant protective shielding, dosimetry, and alerts. Research is also being conducted in the field of medical countermeasures such as pharmaceuticals to help defend against radiation.
2. Isolation and Confinement. Behavioral issues among groups of people in a small space over a long period of time, no matter how well trained they are, are inevitable. Crews will be carefully chosen, trained, and supported to ensure they can work effectively as a team for months or years in space. The more confined and isolated humans are, the more likely they are to develop behavioral or cognitive conditions such as a decline in mood, cognition, morale, or interpersonal interaction; sleep disorders; depression; fatigue; and boredom. Research is being conducted in workload, light therapy for circadian alignment, phase shifting, and alertness.