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At some time in the future, there is a possibility that a probe may be sent to investigate a nearby solar system. If you were the head of a design team how would you (using only today's technologies) propel the craft and, achieve the return of useful scientific data/samples?. Which system would you target and why? What would be a suitable 'Launch to data recovered' period be?
Primary Drive system: Nuclear pulse rocket, piggy backed on laser powered light sail for initial launch.
Sensor Array: Detectors for full electromagnetic spectrum
Control: Comprehensive AI system based on four independent computers
Redundancy: Triple redundancy on two parallel control systems
Communication: Laser
Duration: one hundred years +/- 20 years
Target: Alpha Centauri
Full marks to Ophiolite for attempting to answer this question! I have no knowledge of the technologies which could make interstellar travel possible but I have tried to think about the logistics of this and I very much doubt whether we will be able to do this for decades (probably centuries) to come. some considerations:
1) WHICH SYSTEM? - the nearest star system is alpha centauri, 4.4 light years away, but why should we choose this system? Its a triple star and therefore likely a poor candidate for planets. A promising candidate for planets is epsilon eridani, a sun-like single star but this is 10.5 LY away. Maybe we shouldn't limit ourselves to one system? If we can make a 'cheap' probe why not launch simultaneously for alpha a-centauri, sirius (8.6 LY) and e-eridani? Can we observe multiple systems with a single probe over centuries by calculating gravitational slingshots?
2) SPEED/TIME PROBLEMS - would scientists be happy devoting years of their careers to a probe which won't reach its target in their lifetimes? I seriously think any probe that takes over 30 years to reach its system is a non-starter (but then we need speeds of at least 0.25 times c). Will our probes propulsion system be surpassed during its flight time? (could we launch probes years later that would get there sooner?) Another time consideration is can we make probes that we are confident will still function after 30-100 years in the cold of interstellar space?
4) OBSERVATION TIME - if the probe is travelling at 0.25 x c or faster we would get less than an hour at earth type distances to the star. Any planets detected are likely to be too distant from the probes trajectory to be analysed in any meaningful way. Can we slow the probe down once it reaches a system? Even better could we insert a probe into orbit while we analyse the system and then manouvre it to investigate planets?
3) DISTANCE/COMMUNICATION PROBLEMS - would lasers allow communication? do we have the accuracy to communicate back and forth over 4+ light years with this technology? If we can achieve orbit is it even feasible to communicate over 4 LY to alter a probes trajectory/orbit?
5) AND FINALLY - is there really much info that we could get with a probe (that we can't meaningfully communicate with) which we couldn't get from improvements in space telescope technology while the probe is on such a long journey?
The problem seems speed. What we need to manage to do is send probes near the speed of light. Which may not happen anytime soon, but it's good to start thinking about. After all, if no one is thinking about it, then nothing will ever happen.
What about the journey itself? 5, 10, 20 years after its launch, wouldn't that bring about images of never before seen perspectives of the universe? Although it won't reach the main goal, we would still be able to see it's path, and in my opinion that would be exciting in a way too.Quote:
Originally Posted by electricant
Well, if the probe is sent equipped with communication nodes and every X amount of distance, one of those nodes is left behind in the path (like cookie crumbs), it will create a chain to communicate between the probe and Earth.Quote:
3) DISTANCE/COMMUNICATION PROBLEMS - would lasers allow communication? do we have the accuracy to communicate back and forth over 4+ light years with this technology? If we can achieve orbit is it even feasible to communicate over 4 LY to alter a probes trajectory/orbit?
I don't think objects like that would be capable of travelling at the speed of light. Best bet would be worm holes (if they can be done).Quote:
Originally Posted by The P-manator
yes time is a problem by the next century people will just forgot about the probe
I'd like the thread to stick to current technologies please, so wormholes and time machines are out.Quote:
Originally Posted by Osiris
Electricant - Nice considered response.
I can give some info: The Voyagers are still going (after 30 odd Yrs) They are making a silent but significant contribution to future interstellar travel. The fact that they are 1970's tech (pre-PC) and still functioning is evidence probes can survive. They are currently around 9 Billion miles from earth (100 AU).
Communications: The technology is around to communicate with a probe - there are problems with regard to sensitivity (ability to receive a weak signal) but these are not insurmountable.
Even if new/future probes would overtake ours it is still viable to send slower ones. You learn something from every mission, indeed the Voyagers would both have failed if the (pioneers?) had not been sent out first, (a couple of 'cheap' probes to assesss feasibility of crossing the asteroid belt [a vast underestimation of their importance]) - they found the tremedous radiation from Jupiter which led to a re-design of the voyagers to 'harden' them against radiation.
For travel you need to calculate an ACD plot (Acceleration,Constant Velocity, Deceleration). It's no good hitting the gas and leaving your foot there you have to slow down (as I think you said).
The probe would need to have computer systems in hibernation until required. As for finding whats there (planets etc) Visual and radar sensors would be useless. The best way to find planets would be to spiral down towards the star and 'sense' minor deviations in your path which could only be due to the presence of other bodies. Meantime IF telescopes improve to the point where planets can be detected then it may be possible to direct the probe to look at a particular object.
I believe there is a chance to launch probes from the moon using a long linear motor, It is possible to accelerate mass to quite high speeds, BUT there is a limitation that is related to the maximum usable frequency you can run the motor at which in turn determines the 'release' speed. I think the max speed is about 1.8 Kilometres/second at present this is not sufficient to escape the moon's velocity so some extra 'oomph' would be required.
Target system: I'd limit it to 12 light years(about 30 stars?) - and send probes to several systems, maybe even the closest 10 systems. Sirius I'd agree with. We would get some data back from something!
If that's what happens, then we must not let the probes get out of people's minds. Because if people forget, well, the mission is for nothing.