Terraforming is an idea scientists have given serious thought to, but the technology is a *long* way off. Should anything disastrous ever happen to our planet -- over a long period of time -- our only chance of survival might be to adapt a neighboring planet to our needs. The first thing we would need of course would be a breathable atmosphere, which means 3 parts oxygen, 1 part nitrogen, and at reasonable pressure (say no less than the pressure at about 15,000 ft altitude on Earth). The best way to generate a breathable atmosphere is likely by using plants (after perhaps increasing the pressure by releasing gases frozen in the polar ice caps). That means we would also need *lots* of water, and a way to protect the plants from the freezing temperatures. So lots and lots of greenhouses I guess. Presumably these would have to be built on the planet, because it would be too inconvenient and costly to somehow ship them from Earth. Therefore there would need to be a large settlement of humans on the planet, all in habitable domes, with some means of processing the native materials (i.e. the rock). Etc. Etc.
As you can see, this would be quite a challenge. We have a hard enough time sending single automated probes to Mars, never mind entire colonies of people. So, fiction? No. How long would it take? Hundreds if not thousands of years, depending on how desperate we are!
Derek C. Richardson
2. How long it would take for us to send astronauts to walk on Mars. I would guess it will take us at least 50 maybe 100 years before astronauts walk on Mars.
There are two main issues:
a) When will we have the technology to send people to Mars? My guess is that we are pretty close now. I don't think that this is the limiting factor - I think that we will get the technology within a decade once we have decided that it is important to send people to Mars.
b) When will we have the money to send people to Mars? Sending people into space is very expensive. We could send tens to hundreds of Landers and satellites to Mars for the price of one manned mission. In addition we would get a lot more information from the unmanned the field of astronomy which in turn brings in money. So we need to maintain this delicate balance between doing science and keeping the public aware and intrigued.
Zoe Malka Leinhardt
3. In your opinion, what technology might we be using for short-term space travel to go, say, to Pluto, in our vaguely immediate future?
The answer depends on whether you want to send just a spacecraft to Pluto, or you want humans to go. For spacecraft, it will happen with the launch of the Pluto-Kuiper Express in 2006, arriving in 2012 (see http://nssdc.gsfc.nasa.gov/nmc/tmp/PLUTOKE.html). This will use a standard rocket launch followed by a "gravity assist", which is where the spacecraft is sent by other planets to use their gravity to speed up the craft.
For humans, it depends on how long you want to take. In terms of propulsion I'm no expert but I think that several options exist, including standard rockets, nuclear propulsion, and maybe even things such as ion drive or light sails. The issue, though, is that you'd need a lot of food and drink per person (several times your weight), and even more importantly, you'd want the humans to arrive and return alive! That's a pretty serious issue even for shorter trips such as to Mars. For example, radiation due to radiation from solar flares is likely to be lethal on the way to Mars unless serious shielding is applied, and that would add weight, which would add the need for more fuel. Not an easy question at all!
Cole Miller
4. I had a question I would like to ask you. if its not to much trouble it would be greatly appreciated if you could answer it. My third question has to do with living in space. Is this a possibility? If so when can you predict this will happen?
Living in space aboard the International Space Station has been possible. There are some hazards or discomforts associated with the experience. In "zero gravity" you muscles aren't exercised like they are used to on Earth. There is loss of muscle mass despite some exercises that have been developed and are used by astronauts in space. During times of solar activity when huge erruptions on the solar surface release tremendous quantities of energy and fast moving particles, sitting in a space station isn't the best place to be. On Earth we are protected by our atmosphere and the magnetic field. Actually the space station is protected by the Earth's magnetic field since it is orbiting Earth. Once beyond Earth orbit, like if you are thinking about going to the Moon or Mars, this becomes a larger problem. Any shielding that is added contributes to weight in your spacecraft and that makes launching it more difficult.
Engineers are wonderful at solving problems like this and I am a firm believer that almost all things are possible. As to when space travel or living in space will occur, is hard to predict. It basically comes down to how much money and resources do you want to spend on this goal. With current budgets, it may be another century before limited resources and funds can help us reach this goal.
Please ask another question if you would like.
Grace Deming
5. i wanted to know how far did the humanity go in the universe???
The first man in space was a Russian cosmonaut, Yuri Gagarin, on April 12, 1961. The NASA Apollo program (1961 - 1975) delivered men to the surface of the Moon. There were 13 flights of which only 2 were unsuccessful. The astronaunts returned lunar samples which are still being studied. This is as far as people have ventured from the Earth, as far as human spaceflight is concerned. However, several unmanned spacecraft, Pioneer I and Voyager I and II, have now crossed the Heliopause, which is considered to be the extent of our solar system. Voyagers 1 and 2 were launched in 1977 to study Jupiter. After leaving the Jovian system, they have continued to collect and return scientific data to this day. Pioneer 1 and Voyager 1 are headed in opposite directions away from the Sun. A small spacecraft, New Horizons, is on its way to the dwarft planet Pluto, and this will complete our unmanned exploration of the planetary system out to the Kuiper Belt. Some planets have been visited multiple times by unmanned spacecraft: Venus, Mars, Jupiter have been targeted by multiple spacecraft and many spacecraft have landed on Mars. We do not have a manned presence on any other planetary body at this time.
Rosemary Killen
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