Can we just go to Mars already?
Absolutely. Just pm thenewgreen, and maybe let him know what topics you're interested in.
- Yeah, you can be in them too!
If by "we" you mean robots we create, then I think we may yet do that. Human space endeavors will likely be the product of private venture IMO and not NASA.
I personally believe we need both humans and robots for studying and studying in space. In some cases of course, humans are unneeded and any robots can be used as a proxy so to speak for humans, but you have to keep in mind there is no computer (or at least not one we can send into space) that rivals anyone's ingenuity or curiosity, which is exactly what is need for many studies.
Increasingly it is starting to look like NASA's direction will be robotic endeavors while private industry like Virgin and SpaceX focus on human space endeavors and recreation. Which is fine by me, it's my hope that the two can exist symbiotically.
If you're interested in Space, check out the last Hubski podcast, it was on Space
I agree that humans have a degree of flexibility that computers will not have for a very long time. I'd say, however, that this flexibility is not of extra use more often than it is. What was the last time we took scientific data that absolutely required a human to be along for the ride? Tack on to this (1) that spacecraft can be remote controlled safely from Earth, (2) autonomous control systems are getting smarter and more powerful each year, and you have even less practical incentive to put a human on board. Obviously if the distance from earth is significant, the degree of control is lessened because of the transmission time, but that's another discussion.
I am a staunch supporter of a continued human presence in space exploration, but I can't deny that the current state of technology and funding make it utterly impractical. The benefits to having humans along are almost always outweighed by the drawbacks, especially in an era that struggles with heavy lift technology. Perhaps the solution is to simply wait until propulsion, life support, and launch technologies mature.
For Mars the ion drive will be too slow. It would need fossil fuels in the first place to get into earth's orbit (of which in 50 years there would not be much left - end of the space era?) and then it would need to speed up to at least 40.000 km/h to escape the earth's gravity well. Imagine a spaceship for a crew of 4 astronauts: habitats, exercise rooms, lots of storage for food and oxygen, the lander- and take off module with its own load of storage for fossil fuels to escape Mars' gravity well (something more than a quarter of the earth) and for braking the speed at Mars and reentry back at earth and the equipment for various experiments. You can cut down on some of that by making it a suicidal one-way mission but it will be a lot of weight. More than the Apollo missions for sure. Now imagine putting a a roll of toilet paper on top of that; that'll be the amount of thrust an ion drive would give it. We can go to Mars but it will require a lot of willpower, a lot of money, a whole lot of energy, not enough time and many sacrifices. Personally I think there will never be manned Mars missions.
- Dawn, a NASA probe that’s powered by previous-generation NSTAR ion thrusters, accelerated from 0 to 60 mph in four days
Sounds like my car.
- Ion thrusters work, as the name suggests, by firing ions (charged atoms or molecules) out of a nozzle at high speed (pictured above). In the case of NEXT, operation is fairly simple. Xenon (a noble gas) is squirted into a chamber. An electron gun (think cathode ray tube TV) fires electrons at the xenon atoms, creating a plasma of negative and positive ions. The positive ions diffuse to the back of the chamber, where high-charged accelerator grids grabs the ions and propel them out of the engine, creating thrust. The energy to power the electron gun can either come from solar panels, or from a radioisotope thermoelectric generator (i.e. a nuclear battery, just like Curiosity).
Just like that.