Earlier this month, NASA released a road map outlining how it will approach the historic mission aimed at sending mankind to Mars. Join us as we take an in-depth look at the plan, and the technological challenges that must be overcome if the agency is to undertake humanity's next step in its race to the stars.
At first glance, theincremental road map could be mistaken as overly cautious in nature,but we have to take a step back and view the endeavor through awider scope. As a species we only (relatively) recently achieved the power offlight. Since then advances in aviation and then aerospace haveoccurred at an astonishing rate, leading to us placing men on theMoon and finally establishing a long-term presence in low-Earthorbit (LEO).
The problem is, puttinga man on the Moon is nothing like extending the domain of human spaceflight to another planet. As it stands, we are aware of countlesstrials and technological hurdles that must be overcome, but the truechallenges are the unknowns that will inevitably rear their uglyheads as we walk down the difficult path ahead.
Technologicaldifficulties aside, the agency must keep the astronauts healthy, andassess the behavioral and psychological effects such a journey wouldhave on the crew. One of the key mental aspects for the crew will bedealing with the extreme isolation from Earth in a confined space, inthe knowledge that should the worst happen, there is no abortoption, and the nearest help is millions of miles away.
With this in mindNASA's newly-released road map heavily emphasize independence,reliability, in-situ use of resources and automation as a means ofmitigating the risks of a manned mission, and its reliance on thehome world. NASA has split its road map into three distinct phases –Earth Reliant, Proving Ground, and Earth Independent.
Earth Reliant
The first leg of NASA'sjourney has already been operational for nearly 15 years. The momentthat mankind sent astronauts and cosmonauts to the ISS back inNovember 2000, we began the incremental process of learning how tokeep human beings alive in space for prolonged periods of time. Thisis the key element to the agency's Earth Reliant phase, which willunfold aboard the ISS.
Man's time in LEO hastaught us that we require effective exercise regimes, drugs andequipment to prevent muscle and bone wastage, as well asa myriad of other unpleasant side effects synonymous with operatingbeyond Earth's nurturing atmosphere.
The ongoing year long mission of Scott Kelly and Mikhail Kornienko in LEO willsignificantly advance our relatively infantile knowledge regardingthe effects of microgravity on the human body and mind. This line ofresearch is vitally important to improving the resilience ofastronauts for a mission to Mars that could last as long as 1,100Earth-days.
Beside the crew healthaspect of the Earth Reliant phase, NASA is testing and developing awide variety of components for the later, more ambitious phases ofthe journey to Mars. The agency plans to utilize the space station'sunique microgravity environment to advance radiation shieldingtechnology, in-situ 3D printing of tools, the capabilities of thenext generation of EVA spacesuit, and many other elements necessaryto reduce Earth reliance.
Proving Ground – cislunar space
Early in the nextdecade, NASA, as part of an international effort, plans to extendits operations to cislunar space – an orbital region around theMoon that represents the ideal proving and staging ground for a deepspace mission. Here NASA can field test elements of a Mars mission inthe knowledge that it would take mere days to return a crew to Earthin the event of an emergency.
Transportation andhabitation are at the top of NASA's list of priorities for operationsin cislunar space. The agency will assess the performance of its nextgeneration Orion spacecraft and Space Launch System (SLS). Unlike commercial crewed spacecraft, such as Space X'sCrew Dragon and Boeing's Starliner, Orion isbeing developed with the sole purpose of operating beyond LEO.
Over the course of the Proving Ground section of the journey to Mars, Orion will beresponsible for keeping the crew safe during launch, transportingthem to a long term orbital habitat in cislunar space, and finallyprotecting the astronauts from the intense heat of re-entry.
The launch stage foroperations in cislunar space will be powered by the first iterationof the SLS, known as Block 1. NASA plans to roll out twoupgrades to the SLS – Block 1B andBlock 2, the latter representing the most powerfullaunch vehicle constructed so far, with a maximum thrust 20 percentgreater than that of the Saturn V rocket that first launched mankindto the Moon.
Block 1 of the SLSrecently completed its Critical Design Review, avital stage in the design process before proceeding to full-scale production. The first outing of Orionand the SLS is currently slated for 2018, although this is subject todelay.
While operating incislunar space, NASA hopes to develop and test a cutting edge SolarElectric Propulsion (SEP) system geared toward the efficienttransportation of habitat and cargo spacecraft between Earth and theRed Planet. The tech would differ considerably from most conventionalspace exploration thrusters, utilizing solar power toaccelerate ionized propellant in order to create thrust.
The resulting enginewould be incredibly low powered, but capable of running for months oreven years at a time, gradually picking up speed. Furthermore thefuel required to power the SEP thrusters, known as xenon, takes uponly 50 percent of the mass for the equivalent fuel of a chemicalengine, allowing for significant savings on launch mass that couldthen be devoted to equipment and supplies.
NASA plans to utilizean advanced version of the system to pre-place resources, landers,habitats and more conventionally-powered Mars ascent vehicles(MAV) on the Red Planet years ahead of a manned mission. The agencyasserts that the thrusters could be reused on further missions afterrefueling, thus creating a more sustainable deep-space presence.
NASA is alsoconsidering the potential of utilizing a hybrid spacecraft boasting bothSEP and chemical thrusters. Such a spacecraft would begin its journeyto Mars from a lunar distant retrograde orbit, using thrustfrom the upper stage of an advanced SLS launcher and targeted burnsfrom its conventional thrusters to supplement the SEP engines, withthe effect of cutting down Mars transfer periods for manned missionswhen compared to SEP only spacecraft.
Many of thetechnologies pioneered by NASA during the Earth Reliant and Proving Ground phases of the roadmap will be field tested via the agency'splanned Asteroid Redirect Mission (ARM), which willleverage the Orion spacecraft, an SLS launcher and SEP technology.The ARM mission, scheduled for launch in 2020, will also present theagency with an opportunity to observe the performance of next generationEVA suits, assessing how they stand up to a spacewalk and contactwith the captured asteroid boulder.
In order to maintain along-term presence in cislunar space, NASA and partners areplanning to deploy an advanced habitation module. Based ontechnologies pioneered aboard the ISS, the modular habitat will allowNASA to mature environmental systems designed to keep astronauts safeover the course of their months-long journey to Mars.
Before being able to actually send a crew to Mars, the agency would have to demonstrate that the habitat had advanced environmental monitoring systems, adequateconsumables storage, high-reliability avionics and exercisefacilities capable of staving off the detrimental effects ofmicrogravity.
One of the principaldangers facing astronauts during Mars' transit is exposure todeep-space radiation. Ordinarily we are shielded by Earth's magneticfield, but in deep space no such protection exists. Prolongedexposure to radiation, galactic cosmic rays and solar particle eventscan heighten risks of cancer and suppress an astronaut's immunesystem.
The radiation can alsopose a danger to ship systems, as was the case with NASA's Dawnspacecraft in September last year, when a high energy radiationparticle struck the probe as it was approaching the dwarf planetCeres, forcing it to enter a safe mode. On a manned journey to Marsthe effects of such an event could mean death for the crew, making atried and tested radiation shield an essential component of thetransportation habitat.
Scientists andengineers will also test how the habitat's systems respond to use after aprolonged period of dormancy. It will be built withstandardization in mind, allowing NASA and partners to addmodules and improve capabilities as operations require.
Earth Independent
The final stage ofNASA's journey will represent the culmination of decades ofexperience in space exploration by both human and roboticpioneers, allowing the mission tooperate with an unprecedented degree of independence from Earth.
Generations of roboticexplorers have characterized Mars, granting us insights regardingwhat can be expected by a manned mission, and what resources could beused to keep human visitors alive. The first astronauts on Mars will be required to harvest localresources, converting them into water, fuel, building materials andof course, oxygen.
The importance ofin-situ resource conversion cannot be understated. For example, NASAexpects that the fuel needed to operate a 35 metric ton MAV would account for more than half of its mass. Ifthe agency can develop a way to process Martian resources in order tocreate the necessary fuel, placing the MAV on the Martian surfacebecomes a much easier prospect.
However, while potential resources on Mars have been discovered, we have yet to test methods of convertingthem into actionable materials. With missions such as NASA's Mars 2020 rover, it is hoped to bridge this gap.Alongside a scientific suite designed to search for ancient life onthe Martian surface, the 2020 rover will carry a resource utilization module designed to test a method of generating breathableoxygen from the Red Planet's tenuous atmosphere.
Thefinal selection of a landing spot for the eventual manned missionwill depend on observations made by the host of robotic explorersnow present on the Red Planet, and those scheduled for insertion over thecoming years.
Manyaspects of the final phase of the mission are still uncertain due tothe inherently unknown nature of operating on another planet for thefirst time. For example, once we get the habitats and equipment in Marsorbit, how do we then safely deploy them? NASA has had successlowering the Curiosity rover onto the surface of the Red Planet via a"sky crane," but this seems an unlikely solution for future missions.
Theproblem here, as is often the case with space exploration, is mass.Curiosity weighed in at under 1 metric ton. By contrast, NASA estimates thatthe modules and supplies required to make a manned mission viablewould require several 20-30 metric ton payloads. This is but one of manychallenges faced by the agency as it attempts to innovate its wayto the Red Planet.
Otherhurdles that must be addressed include the design and testing of a MAV to return astronauts to a transportation habitat in orbit around Mars, and an upgrade to the currentcommunications systems.
Theroad map outlined by the agency represents an incremental yetextremely flexible plan to reaching the Red Planet. NASA states that its path avoids locking itself into an uncompromisingarchitecture, instead favoring a direction that could be adapted tosuit the needs and challenges discovered along the way.
Source:NASA (PDF)
