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NASA Studied Launching Our Nuclear Waste Into the Sun

Starting in the 1970s, NASA studied getting rid of nuclear waste forever by launching it into the Sun. The catch is that hitting the Sun is more than twice as hard as leaving the solar system.

Published · Watch on YouTube · 11 sources

The rabbit hole

The extra context that didn't fit in the Short. Little numbers link to the sources below.

NASA really did run the numbers

This wasn’t a sci-fi idea. In 1973, at the request of the Atomic Energy Commission, NASA looked at shipping nuclear waste off the planet 1. The study judged it feasible, and said it would add less than 5% to the cost of electricity.

The catch was the scale. Doing it the way the study laid out implied more than 100 Space Shuttle launches a year by the year 2000 1. That’s about two Shuttle launches every week.

A 1980 study listed three possible destinations: into the Sun, into an orbit around the Sun, or out of the solar system entirely 2. The plan it looked at sent about 8 tonnes a year, about three Shuttle launches’ worth 2.

Why “just aim at the Sun” doesn’t work

Everything on Earth is already moving sideways around the Sun at about 67,000 mph 4. Launch a rocket and it keeps that sideways speed. So it doesn’t fall into the Sun. It just keeps circling, like we do.

Think of a coin in one of those spiral wishing-well funnels. The coin only drops in because friction slows it down 9. In space, there’s no friction. Your coin circles forever.

To fall in, you’d have to cancel almost all of that sideways speed: about 60,000 mph 5. To leave the solar system, you only need to add about 27,000 mph 6. That’s why hitting the Sun is more than twice as hard as leaving 7.

And it’s even worse than “twice”

“Twice as hard” is about speed. Fuel is a different story. The fuel a rocket needs grows exponentially with the speed change, so needing twice the speed change costs far more than twice the fuel 7.

“What about a slingshot around Jupiter?”

Good thinking, and it works. But Jupiter makes leaving cheaper too. By our estimate, reaching the Sun by way of Jupiter takes about 23,500 mph of speed change, while escaping the solar system by way of Jupiter takes about 19,700 mph 8. Leaving still wins.

Why the canisters in the Short don’t glow green

Real spent nuclear fuel doesn’t glow green like in cartoons. The famous blue glow only appears when it’s sitting underwater in a cooling pool 11. We kept that rule in every shot.

What we’re not claiming

The Short explains why the idea is hard (the physics) and risky (rockets sometimes fail) 10. We are not claiming those are the reasons NASA dropped it. We haven’t found a source that says which reasons mattered most, so we don’t say.

So if we can’t throw it away, what do we do with it? That’s the next Short.

Sources

Every claim in the Short and in this write-up, numbered, with where it comes from. Spot a mistake? Email hello@rigorousrabbitholes.com and we'll fix it in public.

  1. NASA studied space disposal of nuclear waste starting in the 1970s.NASA TM-X-2911 (December 1973), NASA Technical Reports ServerDone at the request of the Atomic Energy Commission. It judged the idea feasible, adding under 5% to electricity costs, but it implied more than 100 Space Shuttle launches a year by 2000.
  2. The destinations studied included launching it into the Sun.Rice, Priest & Friedlander, IAF-80-IAA-50 (1980), NASA Technical Reports ServerLists the Sun, a solar orbit and escape from the solar system among the destinations. About 8 tonnes a year, or about 3 Shuttle launches.
  3. Over a million Earths could fit inside the Sun.Standard astronomy figure (about 1.3 million, by volume) (link to come)
  4. Earth orbits the Sun at about 67,000 mph.Standard astronomy figure (29.8 km/s) (link to come)
  5. To hit the Sun, a rocket would have to cancel about 60,000 mph of that speed.Our orbit math: about 26.9 km/s of speed change to bring the orbit's low point down to the Sun's surface. (link to come)
  6. To leave the solar system, you only have to add about 27,000 mph.Our orbit math: escape speed from the Sun at Earth's distance (42.1 km/s) minus Earth's 29.8 km/s = 12.3 km/s. (link to come)
  7. Hitting the Sun is more than twice as hard as leaving the solar system.Our math, from sources 5 and 6: about 60,000 mph versus about 27,000 mph of speed change. (link to come)That's in speed. In fuel it's far worse, because the fuel a rocket needs grows exponentially with the speed change.
  8. A slingshot around Jupiter helps, but it makes leaving cheaper too.Our math (patched-conic estimate): reaching the Sun via Jupiter takes about 23,500 mph (10.5 km/s); escaping via Jupiter takes about 19,700 mph (8.8 km/s). (link to come)Checked against how far Jupiter can actually bend a path. An independent check by a physics reviewer is still pending.
  9. Coins only spiral into a wishing-well funnel because friction slows them down; in space there's no friction.Basic physics (rolling friction plus air drag) (link to come)
  10. Rockets sometimes fail.General statement. The Short claims no failure rate. (link to come)
  11. Real nuclear waste doesn't glow green.Basic physics (link to come)Spent fuel gives off a blue glow only when it's underwater (Cherenkov light). That's why the canisters in the Short don't glow.