A Human Mission to Mars? Not Yet
Water on Mars
The scientific community was intrigued by the startling announcement in June 2000 that some high-resolution images of Mars taken by the Mars Global Surveyor showed strong evidence of small channels and gullies that appeared to be carved by outflows of subsurface water. Then in March 2004, NASA announced that the Mars rover Opportunity had found spherical formations in rocks (NASA called them ?blueberries?) that seem to point to water once being plentiful on the planet.
First Stop, Mars
Mars is the first nearby world that people from Earth will eventually visit. With its recognizable four seasons, clouds, polar ice caps, mountains, dry river beds, and dormant volcanoes, Mars is the most Earth-like planet in our solar system, and it has the greatest potential for human habitation. Although it has a very cold, dry climate, surface temperatures at the equator can reach 80F during the summer.
Scientists believe that there were once similar conditions on Mars and Earth billions of years ago. Data from past Mars missions suggest that the planet once had a warmer, wetter climate and abundant liquid water?lakes, rivers, and even oceans?during its early history.
A detailed exploration of Mars would give us insights into the past and future of our planet. We might also learn whether Mars could sustain self-sufficient colonies that might prove to be a lifeboat for humanity's survival in the event of a distant future global calamity. Finally, exploring the planet could create new commercial opportunities and sources of income.
A Very Dangerous Mission
A human expedition cannot be attempted until extensive robotic explorations have made a detailed study of the planet, found vital sources of water, returned soil samples to Earth, and located the best landing sites. The Mars Exploration Rovers Opportunity and Spirit are exploring small patches of Mars on opposite sides of the planet. The Phoenix Mission is set to land on the northern plains of Mars in 2008 and features a stationary lander with a robotic arm for exploration. The Mars Science Laboratory, destined for a 2010 landing on the planet is a brawnier version of the rovers. Eventually, however, NASA will develop the critical technologies for long-term human survival in beyond-Earth orbits on the International Space Station and then on the moon base, which will make it possible for humans to make such a journey.
No one knows how many billions of dollars a human mission to Mars will eventually cost, and the enormous financial burden will have to be shared by other nations. The epic endeavor will be far more dangerous and technically difficult to accomplish than it was when we sent men to the Moon over three decades ago. The Moon was only a short hop of 240,000 mi. compared to a 47-million-mi. voyage to Mars. If an Apollo 13?type disaster were to befall them, the astronauts wouldn't be able to return again to Earth.
The monumental challenge of sending humans to Mars for a lengthy stay and then returning them safely to Earth is mind-boggling. Unlike previous space missions, when these astronauts leave Earth, they will not be able to return for almost three years. The trip to Mars will take between four and six months, depending on the propulsion system used. After the interplanetary voyagers arrive on the Red Planet, they will have to remain there for approximately 18 months until the proper alignment of Earth and Mars allows them to blast off for home.
A Hypothetical Scenario
Most likely the mission will require transporting most of the necessary supplies and equipment by unmanned spacecraft to the chosen landing area and confirming their operable condition before the first astronauts even arrive.
During their long, confined stay, the Mars pioneers may live in an inflatable modular housing unit similar to the TransHab (for ?transportation and habitat?) design proposed by NASA in 1997 as a possible replacement for the U.S. crew quarters on the International Space Station. The cylindrical structure would be 27 ft. (8.2 m) in diameter and have a foot-thick protective shell when inflated. The shell would be made of almost two dozen layers of material that is stronger than steel. It would also provide insulation from the extreme Martian temperatures that range from ?199F (?128.3C) during the polar night to 80F (26.6C) at the equator. The module would consist of four levels, for work, health care, crew quarters, and a galley area.
The space travelers will drive for miles across the planet's diverse terrain in advanced-type roving vehicles equipped with specialized tools, drills, and analytical instruments. Much of their time will be spent searching for water and past and present evidence of Martian life forms, and conducting a wide range of scientific activities that cannot be accomplished by robotic exploration.
Survival on Mars
Because it is impossible to take all the supplies that they will need from Earth, the astronauts will probably have to live off the barren land, using the planet's raw materials to provide fuel, oxygen, and most of the food for a primarily vegetarian diet. Possibly some type of ?care? packages of goodies will be sent by rocket to them from time to time to relieve the dietary monotony. The versatile explorers will even have to manufacture the special spacecraft fuel required for their return to Earth.
Their survival in the inhospitable environment will be totally dependent on their combined expertise, specialized skills, and available equipment. When unexpected problems and challenges arise, as they undoubtedly will, the spacefarers will have to solve them with little or no help from Earth. Even their radio communications with mission controllers will be difficult because of the time delay between Mars and Earth. Depending on Mars's distance from Earth, which can vary by as much as 200 million mi. (322 km), radio signals from the planet can take anywhere from 4 minutes to 21 minutes to reach Earth.
Health Issues a Priority
The physical and mental health and safety of the crew during their long, arduous months on Mars are a major concern for mission planners. How do you plan for life-threatening medical emergencies when you are trapped on a far distant world? In 1999, a doctor wintering at a South Pole station found a lump in her breast, but she couldn't be flown out for proper treatment until the end of the harsh winter. If Mars astronauts become perilously ill, they can't be ?flown out? for two years.
The astronauts must also be shielded from harmful radiation while traveling in their spacecraft and when on the planet's surface. And because the gravity on Mars is only 38% of Earth's, ways to counteract any damaging effects of the weak gravity on their bodies, such as progressive bone loss and muscle atrophy, will have to be found. Currently, there is no fully effective treatment for microgravity-induced bone loss, and counter measures against bone loss are a top space science priority.
In March 2000, NASA took one of the first steps necessary in preparing humans to live on Mars when it successfully tested the prototype of a device to produce pure oxygen from the carbon dioxide in a simulated Martian atmosphere. Besides providing breathable oxygen for future colonists, the unit, called the Mars In-situ Propellant Production Precursor (MIP), demonstrated that rocket fuel can be manufactured on Martian soil for the return trip to Earth.
In January 2004, President Bush announced that the United States would put humans on Mars. The plan calls for a base to be built on the moon and then onward to the Red Planet, but experts believe that the first American footsteps on Mars wouldn?t happen any time before 2030. The European Space Agency (ESA) has the Aurora mission to put humans on Mars, also by 2030. In July 2005, the Russian space agency announced they were looking for six volunteers to lock themselves in a mock space capsule for 15 months in preparation for a Mars mission in 2015.