The last humans to visit the moon left the lunar surface in Apollo 17 at 5:55pm EST on Dec 14th 1972, since then no humans have been further than low earth orbit missions and to the variety of space stations that have existed since then.
The question is now, where shall we go next, do we make Mars the next great step forward or do we go back to the moon. This time it’s not down to the space race or national pride but it’s in expanding mans horizons to living elsewhere in the solar system other than the earth and maybe even making a profit whilst doing so.
Even before the Apollo missions had finished, Werner Von Brawn, the designer of the Saturn 5 moon rocket, wanted NASA to mount manned missions to mars and the Soviets were also drawing up their own plans to send men to Mars.
But by the early 1970’s, the huge cost of the space race, the warming in the relations between the US and the Soviet Union and the change of direction by NASA from the Moon to manned space stations and the space shuttle, effectively ended manned space exploration beyond low earth orbit, and Mars, which was always a much more difficult challenge was off the agenda.
However, the exploration of the solar system didn’t stop, From the 1970’s onwards, Robotic probes and satellites have been sent all of the planets. In fact, there have been 40 Mars missions to date, not including flybys, these include orbiters, landers and rovers but though only 18 of them have been actually successful.
Man has a long held fascination with Mars going back to the Romans, and although Mars is not the closest planet to earth, that is actually Venus, it is the most earth like.
In the 1877 Giovanni Schiaparelli reported that he saw long thin lines on the Martian surface, he called these canali, which means channels in Italian. Not long after the noted astronomer, Percival Lowell picked up on these and through his own observations came to believe that Mars must have been not unlike earth in the past and the “Canals” were the work of intelligent beings to try and irrigate the surface.
By the turn of the 20th century, The Canals of Mars had become one of the most intense obsessions in the history of science and although it was later proven to be completely incorrect, it captured the public’s imagination through the numerous newspaper and magazine articles of the time. This led to classic sci-fi books like the “A Princess of Mars” by Edgar Rice Burroughs and “War of the Worlds” by HG Wells.
This fascination with the possibility that Mars could have been once like the earth and that life may still exist, is one of the main driving factors behind sending manned missions there.
NASA has said that its aim is to land humans on Mars during the 2030’s but many question their ability to do so considering the agencies budget and the proposed use of expensive Apollo style expendable rockets.
Elon Musk says that his SpaceX will start sending unmanned cargo flights to Mars starting in 2018 and then every 26 months thereafter. This will be for future colonists to use which he says could be following as soon as 2024 to arrive in 2025.
Compared to the earth, living on Mars would not be an easy task. There are a lot technical issues to overcome let alone the “human” condition and how that would affect the Mars colonists psychologically, knowing that they probably won’t be coming back to Earth.
So let’s have a look at some of the hurdles that any manned mars mission would have to overcome.
Firstly, there is the problem of just getting to Mars. Earth and mars are on differing elliptical orbits at different speeds, at their closet points, this can vary from 36 to 60 million miles and occurs roughly every two years, between those times the distance can increase up to 250 million miles.
This allows for only a narrow launch window and if launched at their closest approaches and with current rocket technology the journey to Mars is around 150 days.
This brings us on to one of the major issues of the very long space journey, radiation.
Its maybe just as well that we didn’t send men to mars in the 70’s and 80’s after the Apollo missions because they would almost certainly have died on route due to the interplanetary radiation.
Probes and robots which have been sent to Mars over the years have revealed just how deadly interplanetary space and the surface of Mars really is.
With this new information and the advancement of technology in the years since Apollo, we have been able to create new radiation absorption technologies for the spacecraft and crew to protect them from the solar radiation.
There are also ways to deflect charged particles from the Sun like high energy protons and solar alpha particles by creating electromagnetic fields around the spacecraft in the same way as the earth’s magnetic field protects us.
But once you’re out in to the deep space and beyond the protection of the earths magnetosphere there is another equally dangerous form of radiation called Galactic Cosmic Rays. These are high energy charged particles that are believed to originate from places like the super massive black hole at the centre of our galaxy, supernovae, quasars, and gamma-ray bursts which could be up to millions of light years away.
These particles were first observed by the Apollo crews as flashes of light which they saw even when their eyes were closed as the particles went through the walls of the spacecraft and hit their retinas or optic nerves.
Galactic Cosmic Rays arrive in our solar system from every angle and can easily pass through spacecraft and human tissues. These pose two problems, firstly when they strike some of the space craft materials they can give off powerful X rays and create slower secondary ionising radiation like neutrons.
Secondly, like the neutrons they can rip apart the molecules that make up human tissue and DNA. This can lead to cancer later on but more worrying for the crew is that new research has shown that they can damage brain cells at the molecular level causing symptoms similar to Alzheimer’s.
This may take months to manifest its self but the long journey times to Mars would easily be enough time to create permanent brain damage if the crew were not protected sufficiently.
When you arrive are on mars the problems don’t stop there. Mars itself also has no global magnetic field like the earth to deflect these energetic particles and the thin atmosphere provides little in the way of protection too, so any habitats will still need to shield the occupants from radiation on the surface and would probably be underground.
Although Mars has a 24.6 hour day that matches the 12 hour day night cycle of earth, it has only 37% of the earth’s gravity and it’s still not known what long term exposure to this low gravity environment will do to the human body.
The atmosphere of Mars is 96% carbon dioxide with only 0.13% of oxygen, compared to the earths 20% oxygen levels. Its atmospheric pressure is also just 0.6% of that on earth, which technically could be called a vacuum.
You would have to wear a pressure suit with an air supply to walk around on the Martian surface. A failure of the suit system would mean death within minutes if you could not get back to a safe habitat.
Add to this the average temperature is around -55 Celsius , although in the Martian summer the temperature at the equator can reach 20 Celsius, in the winter at the poles it’s as low as -125 Celsius.
There are also huge dust storms that can spring up at any time and last for months. These can cover vast areas of the planet’s surface, blocking out the most of the sunlight which would render solar panels, the staple of power generation for most spacecraft, useless. You would have to bring you own nuclear powered generators if you wanted a reliable source of electrical power for your stay and before you could split water ice in to hydrogen and oxygen for rocket fuel.
Then we have the problems that humans have when living under extreme conditions. The nearest we have to Mars on earth is Antarctica, which has a slightly warmer average temperature of -49 Celsius, a breathable atmosphere, plenty of fresh water and no radiation.
Many of the scientists that work all year around in Antarctica suffer from a mental health disorder called “Winter-Over Syndrome” which is characterized by symptoms such as depression, irritability, aggressive behaviour, insomnia and memory problems.
With the long journey to and from Mars and a prolonged or permanent stay, these conditions could be a lot worse. Performing mission critical tasks or just the manual job of building a colony under these conditions would be extremely testing of even the best.
So whilst there is the urge to follow in Apollos footsteps with an audacious Mars mission, many countries are looking to the moon again but this time to build manned bases, develop technologies and use the moon as our Launchpad to the rest of the solar system.
Another reason to revisit the moon is the cost is significantly lower, especially if there is the potential of a huge profit to be made by mining it for rare and very valuable resources. Mars on the other hand will be a massive financial black hole and that should be really thought of as for the advancement of science and mankind as a whole and not a means to a monetary end.
In comparison to Mars, the moon is a much easier place to get men to, we’ve already done it with Apollo but the longest that we have stayed on the lunar surface for was just over 3 days with Apollo 17. This new age of lunar exploration will be a much more permanent affair.
You would think that as the previous leaders in lunar exploration, NASA and the USA would be the front of the que heading back to the moon but that may not be how it’s going to happen this time around. NASA had plans to go back to the moon with the Constellation program but those were scrapped in 2010 by the Obama administration in favour of a “flexible path” approach to space, starting with landing a manned mission on a near earth asteroid first then a manned mars mission.
The next lunar expeditions will be a more international affair with both Russia and China having said that they will build permanently manned lunar bases and the European space agency has said that it is interested in developing its “Moon Village” concept with other international partners.
At around 237,000 miles and with a journey time of about 3 days, establishing a lunar colony would be a lot easier undertaking as supply rockets can be sent on a regular basis as well as shuttling people to and from the earth.
There is still the radiation issue from high-energy protons as you fly through the van allen belts but these are not difficult to shield against and this was done with the Apollo missions.
Once on the moon there is no atmosphere or protective magnetic field, so radiation is still a problem. Most of the Plans put forward for lunar bases are underground structures which would give the inhabitants more protection from the solar and cosmic radiation.
As there is no atmosphere, there is no weather or any other obstructions like the Martian dust storms to block the sunlight required to use solar panels. However, the moon takes 29.5 earth days for it to complete one rotation relative to the sun. If you had a lunar base at the moons equator, where the Apollo missions landed, it would be light for almost 15 earth days and then dark for the next 15.
The poles of the moon are quite mountainous with deep craters. Unlike the earth the moon tilts over only 1.54 degrees so that the lunar polar regions stay in almost permanent sunlight on the high points of the north pole and the floor of the deep craters of the south pole were the sun never shines, is the coldest places in the solar system where the temperature is around -243 Celsius and this where water ice is believed to exist in large amounts.
It’s not just water that could be used to make rocket fuel that lunar prospectors are interested in, there are other resources like Helium 3 which is the main fuel candidate for future nuclear fusion reactors. This is extremely rare on earth but is believed to exist in large quantities on the moon.
This would be worth hundreds of billions of dollars as a new fuel source and the Chinese have said that it would be one of their primary goals once they are on the moon, to mine for Helium 3.
So with all this new interest in the moon from Russia, China, India and the Europeans its seem strange that the US would just let everyone else take the initiative.
But as they say, a week is a long time in politics, so the 6 years since Obama said the moon was off the table is almost an eternity.
Recent congress hearings have been very critical of NASA’s Mars initiative, attacking its clarity and cost, which is likely to be in the hundreds of billions of dollars and with a narrowing budget it’s hard to see how it will to come fruition.
In a draft of the new appropriations bill for NASA, congress would look remove the funding for the asteroid mission and put the focus back on the moon which can be done with current technology and working with the private space sector.
With a new president arriving soon and many wanting to see America great again, NASA may well be on a new “flexible path” back to moon much sooner than would have been thought possible a few years back and Mars may end up being the first celestial body to be visited by a private space company.