Improved versions of a nuclear drive. Launch systems that require a large infrastructure in space. Lighter materials to build the probe out of.
I read quite a few years ago about a possible technique where if you get a probe way out from Sol, past Uranus, at the right distance you can use the gravitational lensing effect of the Sun’s gravity as an enormous telescope. Supposedly good enough to easily resolve land masses on a planet of another star. I expect that nothing has been done about it because you’d only be able to use that trick to study a single spot in the sky; the only way to change where the “telescope” is pointed would be to move the probe, and it would eventually run out of fuel if you kept doing that. But, assuming I am remembering correctly (and that it hasn’t been proven impossible in the years since then), that sounds like it would work fine for getting a closer look as a specific extrasolar planet you were willing to spend that much on studying, and it would certainly be cheaper and faster than an interstellar probe.
Previous observations showed that there were planets and stars in all sorts of sizes and shapes and other variations that made it a certainty that such a planet existed. This is just confirmation of something predicted by science, and wasn’t really in question.
Science is more about prediction based on past observation than new observations. The observation part is important, but once enough observations have been made, the predictions become more important than each additional observation. If the observation of this planet revealed something new and unknown, it would have greater importance, but it didn’t.
Even building the probe out of Styrofoam or AeroGel will not net you much. Most of the weight will be in the propellant and as noted already you get a serious case of diminishing returns as more fuel = more weight = more fuel needed to push more weight (look at the Saturn V that sent people to the moon…it was mostly fuel and it was huge just to push that relatively tiny capsule from here to the moon).
Assembling in space would be required because we are near our limits in how much weight we can get off the ground on earth with chemical propellants.
As for nukes the Orion thing might do it but it is a long way from the concept to a workable ship assuming it is even feasible given sufficient will to build the thing.
After Orion not sure what could do better that in theory would work and is not sci-fi. And by work I mean as a practical matter. A gazillion jigawatt laser pushing a solar sail and stationed one per AU out from earth might in theory be possible but absurd as a practical matter.
Anti matter is the only thing I can see seriously changing the landscape on this. If we could find a way to mass produce it then a lot of new avenues open up.
However, cool as antimatter is as an energy source it’d probably doom the human race to extinction (imagine a city buster nuke equivalent you could comfortably fit in a purse).
Not simply assembling in space. There’s a variety of ideas for launchers to accelerate spacecraft without the craft needing to use fuel. Spinning tethers, extended space elevators, large linear accelerators, launching lasers or masers.
There’s actually a fairly wide variety of ideas for nuclear drives as I understand it.
Why? Your problem seems to be that you’ve decided that we are at pretty much the apex of possible technology, and we aren’t even close.
By the time we or our posthuman descendants can do that with antimatter (assuming that is even possible) we’ll be all over the solar system. If we have that kind of energy to play with zipping around the system will be fairly easy. Destroying life on Earth would only be a setback not an extinction event.
In theory, all stars have a goldilocks zone. In practice, not all do. A double star system may have the two stars close enough together that the varying light from the two stars means that there is no orbit where the temperature is always in the desired range. It’s likely that in such cases, any hypothetical goldilocks zone will not have a stable orbit anyway.
As for stars coming near the solar system, Gliese 710 is due to pass by some 1.4 million years from now. It probably won’t come closer than about a light year, but could come as close as 1000 AUs.
No, the payload mass does absolutely matter. For any given desired speed and any given rocket technology, you can solve for the ratio of propellant needed to payload. Halve the mass of your payload, and you can halve the mass of your propellant. And a lighter payload need not necessarily be less dense, either: It could just plain be smaller.
This is a red herring. Not only is that a big if, but one of the prime ways of learning is by doing, so we build the first probe and from it learn how to build the next, better, probe.
All very true, but there can be workarounds. The second-biggest problem (after time) in space exploration is Earth’s gravity well, which limits the size of the probe and the amount of fuel. So, for example, perhaps we might make a probe that is assembled in orbit or stops off at Pluto or Sedna or wherever to harvest tholins or xenon or whatever which the probe then uses to speed its way.
So, may as well get on with it now. If something better comes along then great! I’d love to see it. As far as we know though (and not because someone hasn’t thought of it yet but because of the very limits of physics itself) that stuff will remain sci-fi.
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Learning by doing only helps you learn how to do what you are doing better. Chemical rockets are quite inadequate for crossing the gulf between planets, much the empty space between stars.
All we would do by sending a probe without the proper tech is learn how to make a slightly faster probe that still has inadequate tech.
If you want to put money towards something that will get us(or at least a probe) to another star faster, you’ll want to pump money into fundamental research, so we can figure out completely new drive systems that would actually be capable of this feat.
Even if we had gave an unlimited budget, built a mammoth ship in orbit instead of an earth launch, launched at a star along the ecliptic to take advantage of earths orbital speed, i can’t see how any modern tech can get you past 500,000 kph, and thats still something like 9000 years just to proxima, making it a completely pointless endeavor.
Develop a drive with 100x the specific impulse of ions, and sure.. We might be in the 100 year business using that fancy drive tech and plain old fission reactors.
Also, I thought it was only 17 light years away. Astronomer Vogt said if we have a vehicle that can reach near-light speed, 20 years to get there.
Hooo, boy. 20 years on a spacecraft?? Most of those years you’d be in darkness it seems.
We’d have to bring lots of DVDs, beer, weed, and at least one deck of cards!
Nah…for those on the spaceship (if they were going near lightspeed) the trip would take considerably less time due to the time dilation they’d experience. For us on earth it’d take them 20(ish) years. I do not know how to do the math but an example is below on just how little time it’d take them. Note for time dilation to be notable they have to get (IIRC) over 90% lightspeed at least (it is not a linear relationship where 10% lightspeed gets you a 10% decrease in time…the effect grows faster the closer to C you get).
The factor that time is dilated (and lengths are contracted) between two inertial frames of reference is just 1/(1 - v[sup]2[/sup]/c[sup]2[/sup])[sup]1/2[/sup], where v is the relative velocity of the two frames along the axis one is moving with respect to the other. So if v = 0.5*c, v[sup]2[/sup]/c[sup]2[/sup] = 0.5[sup]2[/sup] = 0.25, (1 - 0.25)[sup]1/2[/sup] = 0.75[sup]1/2[/sup] = 0.87, and finally 1/0.87 = 1.15, so in a ship moving at half the speed of light, time is slowed by a factor of 1.15 – not terribly much, but definitely noticeable.
Hell, they calculated the guys on the Mir spacestation were about 3 seconds off with earthlings upon their return (6 months or so in space). Not something they could notice really but easily calculated. On a trip that far it’d add up.
If I am following your math at 0.5c instead of 40 years of travel (what we on earth would see them take to Gliese) it’d feel to them like 34.7 years.
Definitely a noticeable difference but not an overly big one in the scheme of things.
