• Question: Is it possible to travel to either Pluto or Neptune to find life? (any person or people have to actually go - not just a space module!) If yes, HOW? Ad if not, WHY? Thanks very much!!!

    Asked by ravaidah10 to Joel, Kristian, Tim, Venus, Zachary on 20 Nov 2013.
    • Photo: Kristian Harder

      Kristian Harder answered on 20 Nov 2013:

      I think it is possible, but stretching the limits of our technology a bit, and stretching the limits of what we want to do as well. A trip to Mars, which people are beginning to think might be doable, will take about a year per direction. Neptune is about 50 times as far away! that may not mean it takes 50 times as long to go there, but it would definitely be a lot longer. And what for? It’s not a very hospitable environment that far away from the sun. We have better chances of finding life closer to the sun. So, if humans went there, the only life they’d be likely to find out there is their own. 🙂 That doesn’t mean we shouldn’t check, but robotic space probes can do almost everything that humans can do, often better (because you don’t have to worry about keeping us clumsy meatbags safe while doing it), and definitely at much much lower cost. That’s why I’d say it wouldn’t be a good idea for us to try and fly out there ourselves – yet. At a later stage, once we have much better technology, it may be much less of an issue, and we might just go there for sightseeing over the weekend. 😉

    • Photo: Tim Hollowood

      Tim Hollowood answered on 20 Nov 2013:

      Nice question. There’s no law of nature that says we cannot go and we have the technology. The problem will be the cost. It will be hugely expensive to build a spaceship that will allow humans to travel that far in safety and in a reasonable amount of time. So it’s actually a political problem: who’s going to pay? In our lifetime it’s much more feasible to go to Mars and I think that will happen.

    • Photo: Zachary Williamson

      Zachary Williamson answered on 21 Nov 2013:

      Yes it would be possible with current or at least near-future levels of technology. But it would be outrageously expensive, it would make the moon landing seem cheap!

      Ok, so you want to go to Pluto to find life. First of all you need to get off the ground. The amount of equipment you would need to take with you just to get there and survive is immense and no one rocket could lift it. You could need to use thousands of small(ish) rockets to lift your equipment into Earth orbit. You would also need to build your spaceship piece by piece in orbit. For that alone you would need a new space station that could function as a shipyard.

      Ok, so now you have your spaceship in orbit. Getting that spaceship to Pluto (or Neptune) is not *that* hard. In space there is no drag, so if you give your spaceship some speed it will never slow down. This means that you can get to Pluto on a relatively tight fuel budget. The best type of engine for this mission would probably be an ion drive. It uses electric field to accelerate xenon ions to high velocities, and then spits them out of the back of the spacecraft. It basically works like an extremely efficient rocket motor. Takes a while to get going, but once it does you can reach extremely high speeds.

      Even so, it will take at least a decade to get to Pluto. You need to keep your astronauts alive for at least double that, assuming this trip isn’t a death sentence. Storing 20 years of supplies on a spaceship is not really feasible, the space requirements would be huge and every kilogram costs a fortune to get into orbit.

      The astronauts would need to grow their own food, supplemented with stores of food types that are hard to grow, like protein. To get to Pluto you would need to bring a farm with you.

      And how are we going to power all of this equipment? There really is only one option considering the power requirements: a nuclear reactor. A small amount of enriched uranium would power the whole ship for decades, although safety would be a hazard.

      Speaking of hazards, space is full of radiation coming from our Sun. On Earth we have the atmosphere and our magnetic field to sheild us, our astronauts are not so lucky. The entire spacecraft would need extensive radiation shielding, which is heavy and expensive. Also, generating a powerful magnetic field facing the Sun would help significantly to reduce radiation damage. Guess we’re going to have to ramp up our nuclear reactor.

      Finally, keeping a crew in peak physical condition in space is not easy at all. Without a source of gravity our bones naturally decay and become brittle. Our muscles also waste away. This is obviously a very bad thing. On the ISS the astronauts get around this by doing vigorous exercise every day to build up muscle and bone mass. Even with 4 hours of exercise a day the astronauts return to earth with significant bone and muscle deterioration.

      For a 20 year space mission the current solutions would not work. The astronauts would need a source of artificial gravity to prevent their bodies from wasting away. Obviously we can’t create our own gravitational fields, but we can simulate the effects by making the spaceship spin, or at least parts of it. Quite the engineering challenge. And your giant rotating spacecraft needs to be engineered so that if it breaks down, a handful of astronauts can fix it.

      So those are the problems with getting to Pluto or Neptune. They aren’t impossible, but the amount of money you’d need, and the amount of risk the astronauts would be taking is phenomenal.

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