I rather see NASA focus on missions closer to home. We should return to the Moon. The Moon is great platform for gravity wave detectors, neutrino detectors, and telescopes. A radio telescope on the Moon linked to radio telescopes on Earth would make a telescope with an effective aperature of the distance between the Earth and the Moon. We should build a Moon base with robots and a couple of astronauts to monitor and repair these experiments. The secrets of the universe are right there.
@Wnderer & @kris: ditto... going to the moon may become a dire necessity in a couple of generations when we run out of resources like minerals. NASA / human race pooling together should focus on cost effective ways to run moon missions!
I agree, but the first issue is making it to orbit easily and without so much chemical energy. I believe using an electric catapault to get small packages up near orbit and using much less rocket power to get the rest of the way would be the best way to speed things along - use Elon's vacuume tube transport technology and go up the side of a mountain a few miles long at 4000mph you are 1/4 of the way to escape velocity and arguably the hardest 1/4 of the flight.
Smaller non-living or non-g-force limited packages could be sped up and launched at much higher speeds and assembled in orbit.
Sending packages to space should be routine by now - and the bonanza of metals, materials processing and who knows what else would be much more accessible.
Worden said an anti-proton pulse could propel space travel at speeds up to one-twentieth of the speed of light, making it possible to complete the journey to the nearest star system in 20 years.
The closest star system is Proxima Centauri, 4.24 light-years distant. If your space ship can truly travel at a constant 1/20 * c, I mean not at its peak speed but steady state, then it would take 84.8 years to get there, as opposed to 20.
If you take our fastest space vehicle to date, Voyager 1, approximately 17.3 Km/sec, it would take more than 73,200 years to reach Proxima Centauri, and more than 75,000 years to reach Alpha Centauri. Both trips would take longer than mankind has been in existence - almost twice as long as homo sapiens has been around. These are the closest stars to us, amazingly enough.
So yeah, we definitely need to go a whole lot faster, and even to "bypass" the speed of light somehow or other. Space warps, wormholes, anything that allows us to find shortcuts between points A and B, through higher dimensions. Star systems that are of interest to us, that we have already detected, are multiple thousands or millions of light-years away. IIRC, the closest potentially earth-like planet we know about is 12 light-years away, and there are numerous within 50 light-years. Those numbers imply right next door, but they really aren't!
As to fussing only with the closest planets or the moon, you know guys, if the cavemen had thought that way, we'd still be living in caves. You have to invest in more than just what's needed for tomorrow. Because the answers to what might appear to be intractable problems might just come from what we don't know or have experienced yet.
Einstein's relative theory says if the object speed near the speed of light, the time on that moving object slows down from "still" observer. It is called Lorentz Transformation. Equasion of Lorentz factor is
Where v=speed of object, c=speed of light.
When v=0.2c, gamma is 1.02. The clock inside the space ship slows down (relative to clock on "still" Earth). only only 2%. It would not make 84.8yers (on Earth) to 20 years (on the space ship)...
Good point. I had ignored the Lorentz Transformation because we're still talking about very low speeds, at 1/20 c.
So okay, while on earth everyone will have aged 84.8 years, by the time you reach Proxima Centauri, those on the spaceship will "only" have aged a little less than 83.1 years.
The other point is, we could postulate that if you can get close to c, then you really wouldn't need to go any faster. Because even though the rest of the universe is aging really fast as you travel, you aren't. So you might say, the traveler should be prepared to leave everything else behind, and never go back to what he knew, but at least he can survive a journey lasting many thousands of years, say.
Okay, but that pesky Lorentz Transformation also applies to mass. Which means that to accelerate the vehicle to relativistic speeds, it will take huge amounts of energy. So for example, assume you travel at a way faster 0.9c, the mass of your spaceship will be 2.3X as great as when it's at rest, and you will age 43.6 percent as much as if at rest.
And that's already up at 0.9c. So to really take advantage of time dilation, since even 0.9c doesn't buy you a whole lot on a journey of 20,000 light-years, you would have to really really pay a price on energy required.
Conclusion: we need to find a way around the speed of light.
One more problem (aside from mass increas and enormous energy required) is, when you travel in near lightspeed, every free-floating space particles become high-energy beam against the space ship. It could be protected by thick foward-facing shiled, but of course it increases space ship mass and will require even more energy to accelarate to near lightspeed.
Then, when getting to your destination, we must slow down. We need same amount of energy to decelarate to "normal" speed. So the space ship must acceralate to near lightspeed from full-tank, use only (about) half of fuel/propelant on board.
Einstein's space is not friendry to space travelers.
@Prabakhar, thanks for reminding me how old I am!! I remember, at 13, looking up at the moon in 1969 and wondering if I would ever be able to go there, and thinking it was probably quite likely. Alas, the human race seems more focussed on pulling each other apart than pulling together to accomplish something like that.
If NASA has such a big budget to fund concepts like solar sail and faster than light travel, then why not? As far as we know, the planet we live on will cease to support this life in 1500 years or so, if the current rate of deterioration continues. For this we must be developing time travelling portals and near light speed for continuation of our life on other planets. NASA is really embarking on a tight budgeted mission.
My goal for the space program would be to double the number of people living in space every 50 years. 12 people by 2050, 24 by 2100, 1 trillion by the year 4000. Then start sending the generation ships to the stars. Humanities (perhaps non-human) descendents cover the entire galaxy in 65 million years. That's only 4% of the years of habitability left for the Earth. The same amount of time since the dinosaurs went extinct. It also calls into question the existence of extra-terrestrial life. If intelligent life has been in the galaxy for 100 million years, they should not be hard to find.
@wnderer raises an important point - that eventually our earth will cease to exist and that humanity needs an exit plan if it is to survive. While the timeframe is much greater than the total time than humans have lived on earth to date, it is a topic that eventually will need to be addressed.
Within this century, I'd think that the advances in robotics and technology make remote exploration of other solar systems the only practical approach. Not only can they send back data at the speed of light but also the spacecraft is spared the need to carry life support and food and provide sufficient space for human beings. Exploration of the moon is viable because the trips are relatively short; expecting someone to remain healthy for a 20 year trip is not.
@Wnderer: I see your point. I don?t understand why NASA exec thinks Moon is a boring place to be. NASA should build an observatory there, maintaining the Hubble is costlier than maintaining an observatory on the Moon.
This is really something as Moon and Mars are the newest edition to the boring destinations to go to. This is when NASA is planning a manned Mars mission and China is on the same lines planning Moon and Mars voyage.