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.
3. Distance from Earth. Mars is, on average, 140 million miles from Earth. Rather than a three-day lunar trip, astronauts would be leaving Earth for roughly three years. While ISS expeditions serve as a rough foundation for the expected impact on planning logistics for such a trip, the data isn’t always comparable. If a medical event or emergency happens on the ISS, the crew can return home within hours. Additionally, cargo vehicles continually resupply the crews with fresh food, medical equipment, and other resources. Once you burn your engines for Mars, there is no turning back and no resupply. Facing a communication delay of up to 20 minutes one way and the possibility of equipment failures or a medical emergency, astronauts must be capable of confronting an array of situations without support from their team on Earth.
4. Gravity (or lack of it). There are three gravity fields astronauts will experience on a Mars mission: weightlessness be-ween planets, 1/3 of Earth’s gravity on Mars, and normal gravity upon returning to Earth. When astronauts finally return home, they will need to readapt many of the systems in their bodies to Earth’s gravity. Bones, muscles, and cardiovascular system will all be impacted by years without standard gravity. Hazards of gravity changes include changes to spatial orientation, head-eye and hand-eye coordination, balance, and locomotion. Fluids shifts could put pressure on the eyes, causing vision problems.
5. Hostile/Closed Environments. A spacecraft is not only a home, it’s a machine. The ecosystem inside the spacecraft plays a big role in everyday astronaut life. Important factors include temperature, pressure, lighting, noise, and amount of space. Everything is monitored, from air quality to possible microbial inhabitants. Microorganisms that naturally live on the body are transferred more easily from one person to another in a closed environment. Extensive recycling of resources —oxygen, water, carbon dioxide, and human waste — is also imperative.
The Latest Robotic Explorer
When the Mars 2020 rover launches next year, its science goal is to look for signs of ancient life. It will be the first spacecraft to collect samples of the Martian surface, caching them in tubes that could be returned to Earth on a future mission. The vehicle also includes technology that paves the way for human exploration of Mars.
Landing a rover like this one gives NASA more experience putting a heavy spacecraft on the surface of Mars; the challenge of landing in the thin Martian atmosphere scales with mass. The first crewed spacecraft will be titanic by comparison, carrying with it life support systems, supplies, and shielding.
Mars 2020 has a guidance system that will take a step toward safer landings. Called Terrain Relative Navigation, the system figures out where the spacecraft is headed by taking camera images during descent and matching landmarks in them to a preloaded map. If the spacecraft drifts toward dangerous terrain, it will divert to a safer landing target.
Mars 2020 will carry a ground-penetrating radar called the Radar Imager for Mars’ Subsurface Experiment (RIM-FAX) that will be the first operated at the Martian surface. Mars 2020 scientists will use its high-resolution images to look at buried geology, like ancient lake beds. The radar could one day be used to find stores of underground ice that astronauts could access to provide drinking water.
To help engineers design spacesuits to shield astronauts from the elements, NASA is sending five samples of spacesuit material along with one of Mars 2020’s science instruments, called Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC). A piece of an astronaut’s helmet and four kinds of fabric are mounted on the calibration target for this instrument. Scientists will use SHERLOC, as well as a camera that photographs visible light, to study how the materials degrade in ultraviolet radiation. It will mark the first time spacesuit material has been sent to Mars for testing and will provide a vital comparison for ongoing testing at Johnson Space Center.
Humans exploring Mars will need more than good spacesuits — they’ll need a place to live. Mars 2020 will collect science that may help engineers design better shelters for future astronauts. Like the Curiosity rover and InSight lander, 2020 has weather instruments to study how dust and radiation behave in all seasons. This suite of sensors, called the Mars Environmental Dynamics Analyzer (MEDA), is the next step in the kind of weather science Curiosity collects.
The Mars Toolbox
When astronauts land on Mars, limited resources will allow for a short window of time each day to explore new surroundings. Instruments that quickly reveal the terrain’s chemistry and form will help them understand the environments around them and how they change over time.
NASA’s Goddard Space Flight Center is testing and refining chemical-analyzing and land-surveying tools that will assist human explorers of Mars. Many of the technologies build upon ones that have already equipped robotic orbiters and rovers that sniff out the cosmos. NASA’s Curiosity rover, for instance, is studying the composition of soil with the help of spectrometers to identify what rocks are made of by measuring how their chemical elements interact with electromagnetic radiation.
Though the technologies powering these tools already exist, NASA’s objective is to make the instruments small and efficient enough to help robots, and one day astronauts, analyze on the spot the composition of the surface of planets, moons, and asteroids. This will allow for well-informed decisions about which few samples explorers can return to Earth on a spacecraft of limited size.
What the team has learned from doing experiments, particularly with astronauts on the space station, is that speed and ease-of-use are essential for space tools. Astronauts doing extravehicular activities (EVAs) have limited oxygen and other resources, so device features such as instrument size, number of buttons, and the data display are crucial. Time spent scrolling through volumes of information means less opportunity to walk farther away from the lander to make new discoveries.
NASA’s sustainable exploration approach is reusable and repeatable, building an open exploration architecture in lunar orbit with as many capabilities as possible that can be replicated for missions to the Red Planet.
Preparing for our Journey to Mars