NASA had calculated that the shortest mission to Mars would last around 1,000 days – about nine months of travel to Mars, a 13-month waiting period while Earth and Mars cycled to the ideal alignment for a return voyage, and then another nine months of travel back to Earth. A mission like that requires a significant degree of Earth independence. No stopping in an emergency. No repair missions. No resupply.
To prepare for that leap, NASA began developing a small space station or “proving ground” for placement in cislunar orbit. For reference, ISS operates at a low-Earth orbit approximately 250 miles above the planet. Cislunar space, approximately halfway between Earth and its moon, is over 100,000 miles out – technically deep space.
Using the Orion crew capsule and the Space Launch System (SLS) launch vehicle, NASA would hone its long duration exploration capabilities over missions lasting between one month to a year while still being close enough to Earth to have an emergency return option.
The Gateway program is still on and planned for development in 2020, according to NASA’s fiscal year 2019 budget proposal. But since the presidential administration change in 2016, NASA’s targets have changed from landing on Mars to returning to the surface of Earth’s moon.
NASA continues to study the Gateway with United States industry and international partners for a configuration that could allow for earlier crew expeditions, more science and technology demonstration capabilities, and increased room for astronauts to live and work. (Image source: NASA)
During the 2018 EnergyTech event in Cleveland, James Soeder, NASA Glenn Research Center’s senior technologist for power management and distribution, shared information provided to agency leadership that steered NASA’s decision from Mars to the moon and – for the most part – it seems that human physiology, or “liveware,” may be the weakest link.
During an extended mission to Mars, the physical deterioration and ailments faced by astronauts on the ISS would become more acute. That includes loss of bone density, one of the more commonly known issues regarding extended habitation in microgravity. It occurs even if astronauts aboard ISS are exercising regularly.
“Another problem that we have that is not widely known is ocular degeneration. When the astronauts get back from the space station after six months, their vision has changed because of the inner-ocular pressure in their eyes. Sometimes it comes back and sometimes it doesn’t. If they’re there for over a year, it’s permanently changed. It never comes back. It’s a huge problem.” said Soeder.
Additionally, radiation is major issue that astronauts would experience on the red planet. Mars has no magnetic field, thus no radiation protection. Scientists believe that without a magnetic field, solar winds have stripped away the Martian atmosphere layer by layer over the eons.
“During a 1,000-day mission to Mars, you’re probably going to be a cancer patient when you get back because you get more than your [Earth] lifetime dose of radiation during a trip like that. Another human problem that is not very well know is kidney stones. More than half the astronauts that come back from the space station develop kidney stones because its very easy for the kidney stones to form in microgravity. And we don’t have an answer for how to fix that,” continued Soeder.
“The other thing that’s interesting is the psychological impact you have. What we’ve found on the space station is that the longer the astronauts are there, the worse their interpersonal relationships are. Consequently, they get into more conflicts, there are bouts of depression – that’s another thing we don’t know how to deal with yet,” concluded Soeder. “Unfortunately, the problem with taking humans to Mars is that we have to take humans. And they’re really sensitive folks.”
Other concerns revolve around sustaining technologies and budget. NASA currently does not have a solution to long-term or closed-loop life support and relies on resupply missions for air, water, and food.
Technology and budget
And while ion drives – which produce small amounts of thrust by bombarding xenon propellant with electrons – are very efficient for deep space travel, the agency also needs to address the need for high-thrust, in-space propulsion systems and high-power surface-based power sources. SAE International recently covered two potential solutions to those technologies, Frontier Aerospace’s Deep Space Thruster and NASA’s Kilopower project, a surfaced-based radioisotope thermoelectric generator.
On top of that, the last time NASA provided a cost projection for a Mars mission, the funding required was estimated at $500 billion dollars. George H. W. Bush received that memo. In 1991.
NASA’s current budget sits at $20 billion.
NASA’s Exploration Campaign builds on a steady cadence of development, starting now, to enable early access to the surface of the Moon and begin assembling the Gateway in lunar orbit. (Image source: NASA)
Although NASA is still discussing human exploration of Mars, the realization of that aspiration is multiple decades away due to technological, physiological, and fiscal limitations. However, the positive note was found in the closing of Soeder’s presentation.
So what next?
Within the next year, the United States – for the first time since the Space Shuttle program ended in 2011 – will be launching own astronauts into space from Kennedy Space Center. Additionally, for the last 40 years, humans have been travelling into low-Earth orbit. Human habitation of deep space in a cislunar orbit would significantly extend NASA’s human exploration capabilities.
Drawing on the interests and capabilities of commercial industry partners, NASA will develop progressively complex robotic missions to the surface of the Moon with scientific and exploration objectives in advance of a human return and possible settlement. Finally, these exploration missions and partnerships will be the foundation needed for when NASA does commit to human exploration of the solar system.
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William Kucinski is content editor at SAE International, Aerospace Products Group in Warrendale, Pa. Previously, he worked as a writer at the NASA Safety Center in Cleveland, Ohio and was responsible for writing the agency’s System Failure Case Studies. His interests include literally anything that has to do with space, past and present military aircraft, and propulsion technology.
Contact him regarding any article or collaboration ideas by e-mail at firstname.lastname@example.org.
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