- #1
skippy1729
For simplicity consider an unmanned probe to a star in our neighbourhood say 10 to 20 LY.
Most discussions of this concentrate on speed and power. But what is the fastest realistic velocity? 40,000 MPH (~ 1/10 of 1% of light speed)? Even at this speed interstellar dust banging away at the ships hull for hundreds of thousands of years is going to be a big problem. Not to mention the occasional pebble or golf ball. The kinetic energy of the impacts increasing with the velocity squared.
If we accept hundreds of thousands of years and build a suitable hull, what about the innards? There will have to be some moving parts. Take a valve for fuel to thrusters for example. It will not be used often but can we build one that will actually function after sitting for half a million years? The conductor traces and semiconductor junctions in the ships electronics are so small that random diffusion may cause shorts and open circuits in such a time frame.
So we want to go as slow as possible to minimize hull damage while not making the trip so long as to allow the inner workings of the probe to "die" of old age. These facts alone place a maximum range for an unmanned probe, unless we want to consider a robotic ship that is capable of remanufacturing itself from extra raw material and recycled stuff. But then we are probably talking about a ship the size of a small city.
Is anyone aware of studies that consider these kind of problems.
You might question the value of an unmanned probe that takes hundreds of thousands of years to reach its target. That might be an interesting topic but I am not concerned with it here.
Skippy
Most discussions of this concentrate on speed and power. But what is the fastest realistic velocity? 40,000 MPH (~ 1/10 of 1% of light speed)? Even at this speed interstellar dust banging away at the ships hull for hundreds of thousands of years is going to be a big problem. Not to mention the occasional pebble or golf ball. The kinetic energy of the impacts increasing with the velocity squared.
If we accept hundreds of thousands of years and build a suitable hull, what about the innards? There will have to be some moving parts. Take a valve for fuel to thrusters for example. It will not be used often but can we build one that will actually function after sitting for half a million years? The conductor traces and semiconductor junctions in the ships electronics are so small that random diffusion may cause shorts and open circuits in such a time frame.
So we want to go as slow as possible to minimize hull damage while not making the trip so long as to allow the inner workings of the probe to "die" of old age. These facts alone place a maximum range for an unmanned probe, unless we want to consider a robotic ship that is capable of remanufacturing itself from extra raw material and recycled stuff. But then we are probably talking about a ship the size of a small city.
Is anyone aware of studies that consider these kind of problems.
You might question the value of an unmanned probe that takes hundreds of thousands of years to reach its target. That might be an interesting topic but I am not concerned with it here.
Skippy