THE CURRENT STUDIES OF NASA
The problem with all previous studies done by NASA on the matter was that they were based on future technologies, which today we still do not know when they will be available. So from the 90's, NASA proposed that further studies on the idea of sending astronauts to Mars were based on current technologies, and the project itself were to materialize in 10 years after receiving the authorization of "Mars or burst."
Going to Mars is quite different from going to the Moon. First is the distance, almost 100 times farther away. Second is that you can not come back immediately, because as Mars does not orbit the Earth the distance is highly variable and travel can only happen when the two planets are close, every 26 months, both to go there and to return back. And to all this the problem of the time between the sending and the return of radio signals, between 15 minutes and half an hour, is added, which implies a certain forced independence by the crew.
In order to reduce risks, critical equipment should be operating at Mars well before the crew departs from Earth. High reliability systems with minimal maintenance shall be used, with redundancies: everything essential for the success of the mission will be duplicated, and everything essential to keep the crew alive will be triplicated. A high degree of automation will be used and crew training will be carefully worked on, as well as crew proficiency, that is, the ability to remember through continuous practice what they have learned.
At this time, NASA is considering a "Mars Reference Mission" with three objectives:
FIRST OBJECTIVE: TO GO TO MARS AND SEE IF YOU CAN LIVE THERE
The first part of the experiment of living beyond Earth was done in space stations. For example, the current International Space Station could be used to test modules that could be needed on a mission to Mars. Current crews spend 6 months in space, but the station is constantly replenished by ships from Earth. The crew of a Mars mission will not have that luxury.
Experience with these stations shows that the ideal crew size is between 3 to 8 people. The habitable volume under study consists of a three-story cylinder, perhaps with inflatable walls to reduce mass.
The unique water-and-oxygen recycling system, with an efficiency of over 97%, is already in use in the International Space Station. Without this saving, a rather-long duration mission would be impossible.
Once on the ground the usable volume can be increased by assembling other prefabricated, inflatable modules, attached by the astronauts to the initial module.
The first missions will be dropped all at the same location on Mars, so that their modules will eventually become the embryo of a permanent base on Mars. Pressurized, surface transports are under study; they shall also be able to recycle water and air. But spacesuits for Mars must not be very complex, because weights on Mars are higher than on the Moon, so walking activities will have to be curtailed to a minimum, to save oxygen and water. For safety reasons, two modules per crew will be on the surface, plus a third habitable module in orbit around Mars, each with their respective supply of food and other consumables.
Current studies estimate the total mass of resources transported from Earth at 51 ton, including food and supplies to the astronauts for 600 days, in triplicate; 2500 kg of medical equipment, this multiplied by three; 50% of consumables for extravehicular activities (calculated at 2,5 h per person per week); two nuclear reactors for electricity, of 160 kW each; fuel cell for electrical power, of 20 kW each, for emergencies, one in each module; carts with portable generators of 15 kW each; and almost two tons of spare parts.
On Mars, a typical day for astronauts would provide for 8 hours to sleep, preparation to sleep, dress, undress; 1 h for hygiene, cleaning, personal communication; 1 h for recreation, exercise, relaxation; 1 h to eat, food preparation, cleaning; and three hours off. The remaining time would be devoted to professional work, six days a week: 1 h per day for overall planning, reporting, documentation, communication with Earth; 1 h for group socialization meetings, biomedical research, health monitoring, medical care; 1 h for system monitoring, inspections, calibrations, maintenance, repairs; and 7 hours of productive activities themselves.
SECOND OBJECTIVE: TRYING TO USE THE RESOURCES OF MARS
The key to this type of mission depends on carrying as little as possible from Earth and trying to live with whatever scarce resources Mars can provide. Carrying a total of 10 ton of equipment per crew to take advantage of these resources is being studied: on the one hand 3-kW solar panels for emergency power, in each module. On the other hand a module for processing the Martian air, by a well known process called the Sabatier reaction, which can produce oxygen and natural gas for fuel, or produce natural gas and water, all from the CO2 of the Martian air plus a small amount of hydrogen brought from Earth. Finally an inflatable greenhouse would permit the cultivation of plants for food, apart from filtering the air and water. However, it shall not be allowed that earthly plants come into contact with the Martian soil.
Thus, at the end of the first mission there would be on Mars a habitation module, a laboratory module, a greenhouse module, two Martian-air processing modules and, at a safe distance, two modules with nuclear reactors. In the second mission one more habitation module would be coupled and another Martian-air processing module will be set. With the third mission yet another habitation module would arrive, so in this way we would have an embryonic base on Mars.
THIRD OBJECTIVE: THE STUDY OF MARS
Many of the investigations would be performed from the very base, where they would be much of the scientific instruments. The spacesuits would allow excursions of a few hundred meters, up to 6 to 8 h. But more travel would also be advisable: the use cars similar to those used on the moon is planned, topless, for distances up to 5 km. Pressurized vehicles with water and air recycling for carrying four people in even longer and more distant trips, up to 20 days and 500 km, are being studied. All this can be supplemented with robot carts, remote controlled, similar to those already used at this time on Mars.
The great advantage of using humans on Mars is that they have the most efficient supercomputers we know: the human brain. The adaptability and decision power of human beings make them suitable for some types of functions that no robot can execute.
Science would be distributed into geological investigations of Martian rocks and soils, geophysical investigations of the atmosphere, magnetic fields and radiation, and biological research, looking for past or present life on Mars.
The observations may already begin in outer space, during the outbound trip and before arriving. Some 400 kg of instruments would be reserved for this phase, such as detectors of particles and fields, a small solar telescope and other astronomical instruments.
About 1 and a half ton of instruments was planned for the surface: it includes a field package for geology, with hand tools, cameras, sample containers, utensils for documentation; geosciences laboratory instruments such as microscopes, instruments for geochemical analysis, and their cameras; a drill for depths up to 10 m (and from the second mission for 1 km, with a mass of 20 ton), geophysical instruments for the hikings; plus another 8 geophysical/meteorological toolkits; weather balloons; a 1-ton, advaced weather laboratory (in the third mission); and an exobiology laboratory, with sealed containers, microscopes and culture media.
Crew members must posses certain specialties besides their general training: in this case it is expected to fly two physicians, one mechanical engineer, one electrical engineer, one geologist and one biologist, and a chemics and a paleontologist could also go, be it men or women.
The tentative schedule for the mission landed on Mars would consist of different phases: at arrival, 97 days for site preparation, construction, verification and a week off; 107 days for local trips, their analysis, the first distant excursion for 10 days plus 40 days for analysis, and a week off; 107 days for the second trip away and analysis, and the third trip away and analysis, plus a week off; 172 days for the fourth distant outing and analysis, a fifth distant excursion and analysis, collecting instruments and a week off; and finally the sixth excursion away from the base and it respective analysis, plus a week off, in a period of 57 days. The last 60 days would be to turn the systems off and to prepare the return. Total: 600 days on planet Mars, not counting the round trip to and from our neighbour in space.
All this draft project is ready since 1999 (subject to change by new technologies), standing by, awaiting the still uncertain order of "hands-on".
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Based on a lecture given at USP, on 23 June 2001. Originally published in ABC Color, on 23 October 2006. Illustration: In this painting created for a NASA study artist Paul DiMare imagines astronauts walking on Mars during a dust storm. The hostile environment that will confront the long-distance space travelers will require highly specialized technologies and systems, including durable spacesuits that will allow the explorers to breathe in alien worlds and protect them against dust storms like the one described here. Illustration Credit: NASA / Paul DiMare. By permission of Paul DiMare.