As NASA Chief Technologist David Miller puts it, the technology that will be developed over the next few decades will "provide critical capabilities that create new jobs and businesses, inspire our youth and lead to futures where we evolve into a species that lives and works throughout the solar system." But for that to happen, there are various challenges that need to be tackled: lighter shuttle materials, advanced power supply solutions, artificial gravity, sustainable food supplies (in space!) and nanotech-fortified materials, just to name a few.

Ready for Mars?

Getting to Mars is going to be a slow and steady march, and the first stage will take place within Earth's orbit. This is where the majority of research and development on human health and support systems will happen. Simply strapping astronauts to a rocket isn't enough; NASA also needs to ensure that anyone it sends to Mars will survive the trip. This research will mostly occur on the International Space Station, but between there and Mars is where the real proving ground lies. That will be where NASA test-drives its Orion manned vehicle, runs tests during missions to asteroids, and experiments with solar-powered electric flight. And that's not including the work to be done on the Mars habitat vehicle. Does it sound a little early to be worrying about a Mars habitat? It's not. NASA needs a 10- to 15-year lead time to get its technology and equipment ready.



The next stage of exploration would involve exploring the moons of Mars, orbiting the red planet and eventually, the surface. This would lead to the fourth stage: moving from exploration to pioneering. At that point, NASA would attempt to establish an extended human presence in and around Mars that's less dependent on materials from Earth; the theme of self-sufficiency appears over and over again across the agency's technology roadmap.

The astronauts

Arguably the most delicate, most priceless part of any hypothetical Mars landing is the human crew that will be packed inside the spacecraft. The majority of human health and life-support advances come with a due date between 2025 and 2030. While the level of radiation that astronauts are allowed to be exposed to over longer periods isn't specified yet, NASA will have to work on improving protection to radiation on lengthier crewed space missions, and provision for other health-based issues, including in-space diagnostics and treatments. It also has its work cut out reducing the inefficiency of current in-space living.

At the moment, less than 90 percent of the available water and less than half of the potential oxygen are recovered from waste materials. A heavy reliance on expendables like filters and sorbent beds to collect this adds another burden to future missions that need to be far more self-reliant. These improvements will apparently come from both evolutionary improvements as well as state of the art technology that NASA hasn't elaborated on yet. Even then, improvements and changes will require heavy testing.

NASA's new Z-2 space suit will still need improving before it's ready for Mars.

Space suits will also need to improve substantially so that they can be worn over long periods. New suit designs will require the possibility of safe in-suit waste management and water provision, while future exploration space suits will demand no more than 10 percent of a wearer's strength for movement, as well as a significant reduction in mass to less than 100 pounds in total. NASA also plans to add voice controls and location tracking inside the suits.

In addition to new designs, material advances integrating "game changing" improvements that add dust protection, power generation and multiple secondary benefits purely from choice of material.

Nanotechnology and nanomaterials will permeate (quite literally) almost everything NASA attempts to build; nanomaterials will offer better structural and functional properties at reduced weights. Improvements to space vehicle material and coatings at the nanoscale level would protect from ionizing radiation, heat and other issues. Nanomaterial's high-level conductive properties make it better than copper and at a third of the weight: NASA reckons it could reduce the weight of wiring by up to 90 percent. The challenge here is for NASA to scale up these nanotech improvements to fit into its plans for the next decade or two. Further into the future, and graphene-based nanoelectronics will be both flexible and stretchable -- and likely to revolutionize the size of electronics.

Given the long-term missions that are likely to occur in the coming decades, microgravity-induced health challenges, isolation-based performance issues and more will need to be tackled differently than the approach used for astronauts that spend (shorter) time aboard the ISS. Vision issues, as well as radiation-induced problems will be dealt with at the molecular and cellular level, while behavior of the crew will be monitored continuously with an appropriate treatment plan setup if the rigors of space get to them.

Future vehicles will also have a "human-centered" design, like those upcoming space suits, making them better-suited to living, while "just-in-time" training will add new skills or improve existing ones as the craft powers toward long-distance missions. The lack of an easy escape route or evacuation option means that more medical hardware will be a necessity. NASA also continues to work on and research artificial gravity environments, with the aim of reducing health degradation in space. And since the crew wouldn't be weakened as much when landing on Mars, productivity would likely also benefit.

Robots are everywhere. And there will be even more to come. NASA plans to use them in every stage of space exploration: as early explorers and robotic assistants in space for crews as well as caretakers of assets left behind. Just like Wall-E. Advances in robotics will ensure the human crew is free to tackle higher-level tasks, and reduce maintenance and other mundane chores. While NASA works on upgrading both hardware and software (especially when it comes to 3D sensing and mobility), the agency is aware that there are safety and trust components to how it's progressing with robotics:

"Traditionally, robots have been isolated from human operators in controlled environments, such as a perimeter cage, to minimize disturbances and keep them from inflicting harm on humans. However, future systems will increasingly require close engagement between humans and machines."

It would be important for a human crew to have the ability to adjust the robots' autonomy level. New systems will learn to identify human locations and actions so that the robot doesn't get in the way, and could also conduct emergency tasks to protect humans. The roadmap even mentions telerobotic surgery developments that have happened in recent years.

NASA's humanoid Valkyrie robot.

Remote-controlled robots and support from Earth will need far more advanced space-communication technology. NASA is already moving its high-data missions to the denser Ka-band, which will then be replaced by optical communication for deep-space missions. Optical comms will offer even higher data capacity, apparently with an equal or lower power and mass burden to spacecraft. With the ever-increasing amount of data coming in from high-level sensors, the space agency will also need advanced cybersecurity built into those data sets. Given the scale of long-duration data gathered, automatic corruption detection or self-healing data sets will be necessary.



Decades from now, NASA hopes "revolutionary concepts" could hugely advance communications in the future. X-ray navigation uses a collection of pulsars ("stellar 'lighthouses'") to create time and navigation standards similar to the atomic clocks behind GPS. However, unlike that system, it's not limited to the array of GPS satellites circling the Earth, as that aforementioned stellar lighthouse array covers the solar system. X-ray communication could also offer an improved way of delivering messages and data, with both a shorter wavelength and higher frequency than optical, microwave or radio. In short, it could work much better than any of those.



Like new communication systems, NASA-based medical advances would likely trickle down to those of us living on Earth. Enriched oxygen generators, medical-grade water generation in confined spaces, miniaturized medical-imaging technologies and biosample analysis would all be of use in rural settings, or rough terrain without medical infrastructure. Dynamic 3D imaging (through MRI, ultrasound and other options) is on the list for future missions -- likely with further miniaturization and integration into other medical equipment.

As you can tell by now, space and weight are very much at a premium. And sustaining the crew in space will require huge advances in gathering in-situ resources: making what's needed from the environment around them. In addition, the reliability of all mission systems, especially habitation, will need heavy improvement, with each component designed to be easier to maintain or repair, ensuring more time is spent on mission activities and less on maintaining systems. That's likely where some of those aforementioned robots could come in handy.

Spacecraft

In space, no one can hear you scream, and no technology fulfills all the demands of propulsion outside of Earth's atmosphere. NASA is banking on improvements here to reduce transit times, thrust level and system complexity (as in, less of that), as well as improved safety and durability. But successes in more left-field sciences could lead to "mission enabling" breakthroughs that will revolutionize space exploration. Electric propulsion uses electrostatic or electromagnetic fields to accelerate a propellant to generate thrust, while solar sails (which we're hearing a lot about recently), work by using a large surface area to reflect solar protons or atmospheric molecules, transferring that into momentum. Solar sails' long-life benefits make them great for monitoring space weather, and observing Earth's polar regions. It's also a relatively inexpensive way to move deep-space satellites.

Solar sails are a lightweight, sustainable method of space travel.

Tether propulsion would use a system of lengthy lightweight cables that would interact with planetary magnetism to create a Lorentz force, or by simply exchanging momentum between the two connected objects. However, challenges here involve the length of the tether system, as well as fashioning tethers that can last in space.

NASA is also researching nascent ideas that could well revolutionize travel in space... given a decade or two. Beamed-energy propulsion, delivered from a ground- or space-based energy source, could heat propellants for motion or move by the force of reflected photon momentum. Electric sail propulsion made of long (we're talking tens of kilometers long) electric wires would interact with solar wind protons to create momentum. Fusion propulsion would use nuclear reactions to create both thermal and kinetic energy for movement. Antimatter propulsion and high energy-density materials -- highly packed hydrogen -- could also offer an effective way of moving in space, once the teams have sorted the science out. And if antimatter propulsion sounds a little distant, NASA's also folded in a breakthrough propulsion that focuses on space-time, gravity, quantum vacuums and other sci-fi-sounding physical phenomena for advanced propulsion ideas several decades from now.

Resources

"Advanced power and energy storage technology can enable missions that are limited only by our imagination." -- NASA, TA 3 Space Power and Energy Storage

Power remains another challenge. It's also one that has to balance many improvements: If the weight of a new power system gets reduced, but has an effect on reliability or comes at a higher price, NASA isn't going to make the switch. If or when a breakthrough comes, though (NASA mentions high-efficiency solar cells that could work at low temperatures), it will enable "once impossible missions."



What NASA develops will dovetail neatly into our Earth-based lives: Fuel cells, portable batteries, all-electric vehicles would likely see immediate improvements from new tech that drips down. New systems that could pull energy back from wasted heat would also improve efficiency and ensure even less power is used.

Stronger, more durable, more efficient solar cells would offer a cost-effective route to Mars for both cargo and crew. They would also help to manufacture fuel and water for Mars surface missions, reducing what needs to go on the spacecraft. However, fission power remains one of 11 Primary Mission elements needed to put a human on Mars. Developing the high-temperature fuel element is a key challenge in meeting this objective, as is ensuring that the system is safe, reliable and affordable. Fusion power continues to be researched too, but gaining the high energy levels needed remains a hurdle.

Without power, explorers would be stuck.

To get to Mars, NASA specifies that the crew will need to generate 25,000 kgs of oxygen (for both ascent and life support) on the planet to ensure successful human exploration. That would also amount to a far more substantial savings of 200,000 kg in lower Earth orbit. As well as mass (and cost) savings in Earth orbit, being able to produce oxygen, water and other consumables reduces mission risk, enables extended exploration stays and can even greatly increase the surface area covered during the mission.



The crew will also need to create tools and manufacture replacement parts: Electron beam cutting, as well as 3D printing as a production method, will need to be adapted for use in space (and, eventually, Mars.) That pesky lack of gravity could be a hurdle, but these techniques would allow for a huge range of different parts that could be designed on Earth then beamed as data to be made mid-mission. Mars pioneers will also need to be able to transform the land on planetary surfaces: A technique called "sintering" would prime uneven ground for landing pads and roads to assist exploration. Again, the degree to which NASA is able to develop greater subsistence from both the environment and by recycling discarded materials would help to reduce what needs to be sent from Earth.

Finally, in addition to oxygen and water, humans need food, and NASA needs to minimize the amount of it that goes into space. In particular, NASA needs a "bio-regenerative food system" (probably something involving plants), which would reduce the quantity of food needing to be resupplied. Future astronauts will likely have the luxury of a fresher menu, with options a little beyond freeze-dried ice cream sandwiches.

NASA has a lot of work to do before it heads to Mars. But if it nails it, space exploration will never be the same again.

[Image credits: NASA, Josh Spradling / The Planetary Society]