The Case for Mars is a book by aerospace engineer Dr. Robert Zubrin. Zubrin founded the aerospace company Pioneer Astronautics and is president of the Mars Society. The book was originally written in the 90′s and has been updated recently in a second edition. The book is subtitled “the plan to settle the red planet and why we must”. That’s definitely an idea I can support! This post has an outline of how human explorers can reach Mars based on information from the book. The book goes into much more detail, but this basic outline presents the major points.
Why go to Mars?
• Mars has subterranean microbial life.
• Mars has water in the form of frozen water on the surface and liquid water underground.
• The cost is within reach of NASA. SpaceX president Elon Musk says the company is willing to develop a heavy launch vehicle for $2.5 billion.
• Existing chemical propulsion is capable from taking astronauts from Earth to Mars in six months. Astronauts would be capable of being in space for that duration, since astronauts and cosmonauts have already spent that amount of time on Mir and International Space Station.
• It would not be difficult to build a small nuclear reactor that could provide power to a base on Mars.
• Mars has vast quantities of carbon, nitrogen, hydrogen and oxygen. These elements are the basis of food, water, plastics, wood, paper, clothing, and rocket fuel.
• Mars has hydrothermal reservoirs that could provide geothermal power.
• Mars can support greenhouses lit by natural sunlight.
Getting to Mars
1. A multistage rocket would be powered by an Ares booster made up of four Space Shuttle main engines and two shuttle solid rocket boosters.
2. The upper stage would separate from the spent booster and send an unmanned payload containing the Earth return vehicle, which the astronauts would use to return home.
3. After six months, the ERV would reach Mars and use its aeroshell to travel through the planet’s atmosphere. The vehicle would remain in orbit for a few days to allow the flight controllers to run through tests of its systems.
4. A landing site would be targeted and the ERV would decelerate to subsonic speeds and open a parachute to gently descend.
5. A few hundred meters above the surface, small rockets would fire to guide the vehicle more precisely before touching down.
6. A truck containing a small nuclear reactor would roll out and be guided away from the landing site.
7. The reactor would power a chemical plant located in the ERV.
8. The chemical processing unit would produce rocket propellant, water, and oxygen by combining Martian air with hydrogen aboard the ERV.
9. Thirteen months after launch, the ERV would be fully fueled and robotic explorers would be deployed to identify an ideal landing spot and place a radar transponder.
10. Several months later, a second ERV payload would be launched from Earth.
11. A few weeks later, a spacecraft would launch to carry the first four humans to Mars. The spacecraft would have with a floor area of 1,000 square feet, a life-support system capable of recycling oxygen and water, food for three years, an additional supply of emergency rations, and a pressurized ground car.
12. After liftoff, the rocket would accelerate through the atmosphere. The upper stage fires is own engines and breaks away.
13. Centrifugal force would be generated to create artificial gravity to habituate the astronauts to the same conditions found on Mars.
14. On the 180th day of flight, the habitation module carrying the crew would find the radar transponder deployed by the robot from the ERV. If something went wrong, backup plans for the crew would include:
• driving the rover to the ERV
• maneuvering the second ERV (that was launched shortly before the crew and is following them on a slower trajectory) to land near them
• using the supplies they brought with them for three years while waiting for another ERV
Living on Mars
1. When the crew had landed safely, the second ERV would land 800 kilometers away and fill itself with propellant to use for a second human expedition. This process could be repeated to establish a network of bases on Mars.
2. Research projects on the surface of Mars would include searching for mineral resources, seeking out easily extractable deposits of water, growing plants in an inflatable greenhouse that was brought to Mars, and searching for life on the planet.
3. After determining which of the base regions offered the best environment (ideally situated above a geothermally heated subsurface reservoir to provide hot water and electric power) each new habituation module would start landing at the same site, thus creating a small town.
Getting Back
After a year and a half on Mars, the astronauts would board the Earth return vehicle, leaving behind Mars Base 1. They would then blast off for the six month return trip to Earth.
Other Important Points
• The best time to travel from Earth to Mars occurs when the two planets are in conjunction.
• Since Mars has substantial gravity and an atmosphere, a spacecraft can reach Mars with a much greater approach velocity and still enter orbit.
• The best trajectories between Earth and Mars for a piloted Mars mission are those that leave Earth with a departure velocity of 5.08 km/s and leave Mars with a departure velocity of 4 km/s.
• The optimal crew would be made up of two mechanics, a geologist, and a biologist.
• The heavy-lift vehicle used to launch the mission would be similar to the Saturn V or Energia rockets.
• The mass of the payloads would be 28.6 tonnes for the Earth return vehicle and 25.2 tonnes for the habitation module.
• Nuclear or solar thermal rockets have the potential to deliver more payload for the same launch mass.
• Shielding could be used to protect against radiation from solar flares and sandbags could be use to protect against radiation from cosmic rays.
• A Mars mission would be less stressful in psychological terms than other human experiences such as going to war or being imprisoned. The astronauts would also still be able to communicate with people on Earth.
• Martian surface material has already landed on Earth, meaning that there are low risks of being contaminated by organisms coming back from Mars. Martian microbes are also not adapted to infecting lifeforms on Earth.
• It is much easier to go from low Earth orbit directly to Mars than it is to go from low Earth orbit to the surface of the moon.
• A Sabatier reactor could be used to make rocket fuel and oxygen on Mars.
• A shortwave radio could be used to send radar pings into the ground to detect water.
• Flying robots could explore Mars and identify the best location for a base.
• A base could be built out of bricks made from the claylike dust on the surface of Mars.
• Geodesic domes made of hard plastic could create places for human habitats and crop growth.
• Mars has abundant supplies of carbon and hydrogen, which are useful for manufacturing plastics.
• Martian soil is probably excellent for crop growth and even richer than Earth soil.
• Mars has abundant metals such as hematite and aluminum that could be used for metallurgy.
• Mars has large supplies of carbon and hydrogen that could be used to produce photovoltaic panels.
• The mass ratio of spacecraft leaving Mars is much less than that of spacecraft leaving Earth. This means that Mars is an advantageous place from which to conduct asteroid mining. Asteroids have precious metals worth hundreds of billions of dollars.
• The cost of transporting a person to Mars would be $320,000 (based on assumptions and calculations in the book).
• Fusion power based on the deuterium/helium-3 reaction could provide an advanced spacecraft propulsion system.
• Terraforming could create an atmosphere on Mars conducive to human existence. This could be accomplished through three major strategies: warming selected areas of the planet with orbital mirrors to release carbon dioxide, creating factories that produce greenhouse gases, or releasing bacteria that produce greenhouse gases such as ammonia or methane.
• A Mars Prize focused on transporting humans safely to Mars and back could stimulate research. The prize fund would be $20 billion dollars. This money would be distributed based on technical milestones and an eventual successful flight to Mars and back.
