NASA switches off Voyager 2 plasma instrument to stretch out juice Engineers have turned off Voyager 2's plasma science instrument in an effort to eke out the veteran probe's dwindling power supply. The instrument has become less useful in recent years due to its orientation relative to the direction that plasma is flowing in interstellar space. It consists of four "cups," three of which …
Hey, I thought it was funny even if the downvoter didn't get it.
H/T to the mostly anonymous scientists and engineers who built the Voyagers and have kept them running all these decades.
I cheered at the launch and may my last breath will be a soft, croaking cheer for them all. Thanks for making a cynical old nerd proud of a small, dedicated slice of humanity amidst all of the dross and turmoil.
Didn't miss the joke, but unless there's a very good justification long term space stuff tends to use tech/processes - particularly semiconductors - that are one or two generations old simply because of the availability of in-service reliability data. Bit like not instantly installing the first issue of a new OS but instead waiting for a couple of revs to get the bugs ironed out.
I've dabbled with electronics a bit for guitar amps and pedals, valves (or tubes depending where you come from) these days are pretty much only used for audio or military/space purposes with only a few exceptions such as microwaves. Everything else has moved to solid state.
I wonder if money could be found to send a probe specifically to investigate space beyond the heliosphere. New Horizons reached Pluto much more quickly so I should think they could load up a ship with cool toys to check stuff out and even get there in 20 or so years.
I also wonder if these things will outlast this 59 year old.
The Voyager space craft for all their longevity and the terrific science they provided, also demonstrate the biggest impediment to interstellar travel - electrical power. Machines could be created to store and revive frozen genetic material to grow a colony on arrival to a new planet. But without the electrical power to operate the machines, the ship would arrive a a frozen block of ice with no means to animate the colonists or guide the ship.
The Voyager craft used radioisotope thermoelectric generators (RTGs) to generate electricity. These have lasted for 50 years but are running out of power - and the space craft have only just left the heliosphere. The RTGs are powered by fission. Packing additional fuel for the journey won't work because the stored fuel will decay just as fast as the fuel generating power.
Fusion isn't the answer either since it also requires a supply of fuel that would last the entire journey. Far too much to be able to carry. And solar cells won't work in interstellar space, too far from any sufficient light source.
Absent some form of warp or wormhole drive, humanity is stuck in our own solar system for a long time to come.
I wonder how big of a collector you would need at the front of the (by now very fast moving) vessel to funnel enough interstellar matter into your fusion reactor to keep going.... To be fair the main issue at the moment is taking all of this propulsion material out earths gravity well. It is not inconceivable that mining the moon or asteroids would allow very different configurations of interstellar ship than we are used to seeing in Sci Fi or IRL Once all that mass is moving, it's moving....
The RTGs aren't powered by fission, they are powered by radioactive decay.
If you want a really long lived power source (and one for which additional fuel can not only be carried, but even manufactured from a more stable feedstock), fast fission would suit very well.
Sure, a fission reactor would likely require more mass than an RTG for a given initial power output, but not as much more as one might imagine if terrestrial reactors are your comparitor - a fission plant in deep space requires no radiation shielding. And such a power plant can operate at full power almost indefinitely - limited only by the amount of fuel carried. Uranium 238 has a half-life of 4.5 billion years, and if that's too short, Thorium 232 has a half-life more than twice as long.
Your instruments (and passengers and crew, if present) will need cosmic radiation shielding regardless of your power source, and the extra radiation from an onboard fission plant can be rendered trivial by distancing power plant from payload, to take advantage of the inverse-square law.
Arthur C. Clarke and Stanley Kubrick included this as a design element in the USS Discovery One, the ship controlled by HAL 9000, in 2001: A Space Oddessy.
> the biggest impediment to interstellar travel - electrical power
I would beg to say that the biggest impediment to interstellar travel is the vast distances involved.
Creating an electrical power source that lasts 50,000 years is pretty trivial compared to some of the other technology you've mentioned (e.g. creating humans from scratch using stored genetic material)
Would a solar sail, once up to speed lose speed between stars? I suppose flipping the sail around at the appropriate time would help decelerate at the other end.
I had to look it up, and it seems Nasa think it might work :) https://www.sciencefocus.com/space/nasa-solar-sail-interstellar-travel
I firmly believe we'll need to send robots with significantly advanced AI ahead of us to prepare for the intergenerational ships that could carry humans that far. Interesting times...eventually.
e=mc2 because science is awesome.
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