Mars is the next goal for space exploration. Some groups wanted to have a man on Martian soil as early as 2030. We have the desire to get there, but do we have the means?
In terms of sheer propulsion we know that Mars is not out of reach; we have been able to send numerous unmanned research craft there (even if more than one has been lost) Current technologies utilise ELVs Expendable Launch Vehicles. The models currently employed in America are the 7000 series Delta II rockets. They have a three-stage deployment system capable of taking payloads into orbit and getting them on their way to Mars this ELV will be used again in August of 2007 to launch the Phoenix Lander, which will arrive on Mars in May of 2008.
All of the missions to Mars have one thing in common so far: they have been one way trips. This, of course, is no good for a manned mission. Any astronauts going to Mars will most certainly want to come back! At this point, getting to the planet involves three main phases. The first is getting out of the Earth’s gravitational pull, the next is traversing the 117 million kilometres to Mars. The final step, and the one that has caused the most problems, is landing. A return trip greatly complicates matters as it involves another take off, this time launching from the Martian surface. Doing this requires yet more fuel. Carrying all the fuel needed for a return trip, as well as an air, food and water supply for a year long journey is a huge feat. But we are taking things one step at a time.
In 1964 NASA’s Mariner 4 managed the first successful Martian fly-by. In 1976 the Viking Landers successfully touched down and beamed back colour pictures from the surface. The next big step is the first unmanned return trip, planned for 2009. The Russian sample return mission is actually heading to one of the Martian moons, Phobos. The aim is to land on the moon, gather soil samples and then return to Earth. It is aptly named Phobos-Gruntgrunt being the Russian word for soil. After this comes the next big challenge, getting human beings there and back. Losing a probe is one thingit’s expensive, and a little embarrassing, but no life is lost. If something goes wrong 117 million kilometres, or a six-month journey, away, there is little hope of rescue.
The first step in getting successfully to Mars relies on a neighbour that is much closer to home our own moon. With barely a sixth of our own gravitational field, the moon’s pull offers the ideal staging ground for any long distance mission. Having such a weak hold on any object upon its surface means that launches are easier and more economical. With less fuel being consumed in launch, there is more available for the journey there and back. It also allows for the possibility of much larger craft, which is a necessity if a minimum of a one year mission is to be supported.
Any such trip using current technologythat of rocketsis going to be costly. If we are ever going to colonise the planet, then other strategies are needed. Faster means of travel that can shorten the one year round trip would be ideal, and anything which uses less fuel is essential. Several possibilities for faster space travel exist, some in the realms of science fiction and some looking much more realistic. The two most feasible methods are solar sails and ion drives.
Solar sails are a relatively old idea following a very basic principle. Physics tells us that light has momentum, a quantity associated with its movement that is conserved. Just as when wind hits a ship’s sail and passes on its momentum, so when a photon of light hits a solar sail the spacecraft will accelerate. And again, just as with sails on a ship, they need to be deployed for long periods of time and require an outside force. This is fine while inside the solar system, as the sun provides an abundant light source. Also, within close proximity to Earth, the course could be altered by firing lasers at the ship (therefore providing force in a different direction). A major drawback, though, arises if you try to leave the solar system. The farther away from the sun you are, the less light is incident upon your sails, and hence you have a lower acceleration.
The other main technology being actively researched and studied is the ion drive. These involve, through various means depending on the specific drive, accelerating particles to high speeds using the electric and magnetic properties of certain particles. These have extremely low thrust values, typically only a fraction of the acceleration due to gravity on Earth, but they can be fired continuously for extended periods of time. The European Space Agency’s SMART spacecraft successfully tested this technology on an unmanned trip to the moon while NASA’s NSTAR drive fired for a total of 678 days. The Dawn Mission will be the next probe to use the NSTAR drive and will be launched later this year (currently set at the 20th of June.)
The benefit of both these systems is that they require far less in the way of reaction mass (the mass of fuel that is irretrievably used in getting to the destination) than traditional systems. And although the thrust is relatively low, it is continuous, so far higher speeds are possible than those attained using chemical rockets.
Getting to Mars is only the first part of the story. Once we are there we need to set up a base, just as we are planning to do on the moon. A lot of people hope that one day we will be able to terraform the planet and make it suitable for human inhabitation. Keep an eye out for the third part of this article where we will be looking at the feasibility of turning Mars into a second home.
Part One of This SeriesTime for a New Home? Colonising Mars http://www.aboutmyplanet.com/environment/time-for-a-new-home-colonising-mars
Related ArticlesDigging Deeper for Signs of Life on Mars http://www.aboutmyplanet.com/extraterrestrial-life/digging-deeper-for-signs-of-life-on-mars
Fresh Water Found On Mars http://www.aboutmyplanet.com/space/fresh-water-found-on-mars
NASA Says It Will Colonise The Moon By 2024 http://www.aboutmyplanet.com/space/nasa-says-it-will-colonize-the-moon-by-2024
New Photos of our Neighbour: The Planet Mars http://www.aboutmyplanet.com/science-technology/new-photos-of-our-neighbour-the-planet-mars
Scientists Revive Hopes of Life on Mars http://www.aboutmyplanet.com/extraterrestrial-life/scientists-revive-possibility-of-life-on-mars
Hawking Says Humans Must Go Into Space http://www.aboutmyplanet.com/environment/hawking-says-humans-must-go-into-space
Explore Mars From Google Maps http://www.aboutmyplanet.com/space/explore-mars-from-google-maps
Photo from http://www.lunar.org/docs/nasa/images/DS1_launch.jpg
