c0nc0rdance: What looks like a reject from the Cherry Life-Saver production line is actually a red-hot fuel pellet of plutonium dioxide (238PuO2) intended for use in a 'radioisotope thermoelectric generator' or RTG, like those used on space probes sent too far from the Sun to utilize solar panels.

What looks like a reject from the Cherry Life-Saver production line is actually a red-hot fuel pellet of plutonium dioxide (238PuO2) intended for use in a 'radioisotope thermoelectric generator' or RTG, like those used on space probes sent too far from the Sun to utilize solar panels.

The decay of the plutonium-238 produces heat, which can be turned into electric current with thermocouples using the Seebeck effect. A full assembly (called a "GPHS-RTG"), as was carried on the Cassini probe, weighed 57 kg (125 lbs), generated 300 watts of electric power, 4400 watts of heat energy.

The decay heat reduces by about 0.8% per year, so it's not an endless source of energy, and mission ops plan for reduced power over time. The US and Soviets toyed with using these terrestrially. The Soviets, for example, had strontium isotope RTG's powering lighthouses along the Arctic Circle.

Missions after 2010 used an updated and potentially safer model called the "multi-mission radioisotope thermoelectric generator", which powered the Curiosity rover on Mars' surface. Three more units await future missions, with useful lifespans of about 17 years a piece.

See, I consider it a bonus to have radiation power supplies, because we can mutate our astronauts in route to be sure they have Hulk-like powers on arrival to kick alien butt. But also, some very cool science.

Bonus thread! Want to know what radioisotope power generation has in common with PCR detection of SARS-CoV-2? Read this thread, paying careful attention for the "Seebeck Effect" I referenced above!

Let's talk about how a "PCR machine" (thermocycler) works. PCR requires reactions be heated/cooled rapidly to denaturation (95°C) & annealing/extension temperatures (45-75°C) 30 or more times. So how do we make a compact device capable of changing temps quickly & repeatedly?

I recognise the picture from an article I read on Bellona.org. They have tracked the issue of abandoned RTGs for the past two decades or more. bellona.org/news/nuclear...

Two strontium powered lighthouses vandalised on the Kola Peninsula - Bellona.orgbellona.org Two Strontium containing Radioisotope Thermoelectric Generators, or RTGs, used to power navigation beacons and lighthouses were found literally ripped to pieces by unknown vandals during regular check...

"general purpose heat source", i've been called similar things by people who've slept in the same bed

xkcd.com/2115/

Plutoniumxkcd.com

Ah ok, so THAT’s what Energon is…

If it continuously generates this much heat, then how does the probe get rid of excess heat? I mean, it's in space, so it can only radiate heat.

Good question! Answer: I don't know. The fins are clearly facilitating emission energy, but I'll be darned if I know how it works, other than by simple radiation.

Forbidden lozenge...

I MUST TASTE THE FORBIDDEN GUMDROP

You can do that. But just once.

Don't you oppress me

I don’t make the rules

So what you're saying is it *isn't* cherry-flavored?

That costs extra.

If people have RTG or thermoelectrics questions, we might be able to help....

Crazy how damn near all of that plutonium was a different element before it got alchemy'd into what it is now.

*spits it out* NOW you tell me?

Can you give us an idea of how big this thing is? Like the size of a grain of salt or more like a gumdrop or a golf ball?

About 5cm (2 in) across and 10cm tall (4 in). For comparison, a golf ball is 4.2 cm across. So this is like two golf balls stacked on top of each other.

I shall eat the forbidden life saver and then I will destroy the sun

I would like a dozen please

Spicy cherry candy

Size?

With sprinkles on top

Post