Orbiting nuclear reactor

Orbiting nuclear reactor

Author
Discussion

MartG

Original Poster:

21,252 posts

211 months

Friday 3rd April 2015
quotequote all
An interesting article about the first experimental nuclear reactor in orbit, launched 50 years ago

http://www.drewexmachina.com/2015/04/03/50-years-a...

This could be a prime driver to develop a new spacecraft capable of returning sizeable payloads safely to Earth ( it's orbit is too high for the Shuttle to have retrieved it ). It would probably require a manned mission, as it would be necessary to detach the reactor payload from the spent upper stage of the launch vehicle.

Simpo Two

87,117 posts

272 months

Friday 3rd April 2015
quotequote all
Why do we want it back?

It's normally the getting it up there that's hard; Newton does the down bit quite well.

MartG

Original Poster:

21,252 posts

211 months

Friday 3rd April 2015
quotequote all
Simpo Two said:
Why do we want it back?

It's normally the getting it up there that's hard; Newton does the down bit quite well.
If we go and retrieve it, we can control it's descent instead of leaving it to chance when and where it will come down. Also preferable to grab it while it's mostly still in one piece rather than broken up into little radioactive bits all over the sky wink

davepoth

29,395 posts

206 months

Friday 3rd April 2015
quotequote all
MartG said:
If we go and retrieve it, we can control it's descent instead of leaving it to chance when and where it will come down. Also preferable to grab it while it's mostly still in one piece rather than broken up into little radioactive bits all over the sky wink
It would be better to send a little robotic satellite up to it to push it out into a much higher orbit, if it's going to be a problem. That is what happens with a lot of satellites these days - they keep a bit of fuel left over to park it when they're finished with it.

MartG

Original Poster:

21,252 posts

211 months

Friday 3rd April 2015
quotequote all
davepoth said:
MartG said:
If we go and retrieve it, we can control it's descent instead of leaving it to chance when and where it will come down. Also preferable to grab it while it's mostly still in one piece rather than broken up into little radioactive bits all over the sky wink
It would be better to send a little robotic satellite up to it to push it out into a much higher orbit, if it's going to be a problem. That is what happens with a lot of satellites these days - they keep a bit of fuel left over to park it when they're finished with it.
the current orbit won't decay for 4000 years - but even in a higher orbit it could still be hit by debris and disintegrate - and do we really want to leave nuclear reactors floating around and expect our descendants to sort them out ?


hedgefinder

3,418 posts

177 months

Friday 3rd April 2015
quotequote all
MartG said:
the current orbit won't decay for 4000 years - but even in a higher orbit it could still be hit by debris and disintegrate - and do we really want to leave nuclear reactors floating around and expect our descendants to sort them out ?
why not .........we generally do this with everthing else.....

Simpo Two

87,117 posts

272 months

Friday 3rd April 2015
quotequote all
MartG said:
the current orbit won't decay for 4000 years - but even in a higher orbit it could still be hit by debris and disintegrate - and do we really want to leave nuclear reactors floating around and expect our descendants to sort them out ?
I think Planet Earth probably has more pressing things to attend to.

By the way, what would happen to uranium on re-entry? Can it 'burn up' like other metals? If so, are the products of that radioactive too?

Nimby

4,907 posts

157 months

Saturday 4th April 2015
quotequote all
Simpo Two said:
It's normally the getting it up there that's hard; Newton does the down bit quite well.
Ignoring atmospheric drag (which isn't "Newton") don't you need exactly the same amount of energy to move out of an orbit as it took to get into that orbit?

Eric Mc

122,861 posts

272 months

Saturday 4th April 2015
quotequote all
You do.

In other words, you need to use as much energy to slow down as you did originally to speed up. However, the "slowing down" does not have to be provided by on board rocket motors. Atmospheric drag is the main factor in slowing an orbiting spacecraft or satellite down so that it eventually re-enters. Gravitational perturbations by by other bodies, such as the moon or sun, could slow an object down and even things like the solar wind or the earth's magnetic field can affect the orbital speed of an object.

The earth's atmosphere actually wobbles in and out like a jelly so sometimes at (say) 400 miles distance there is little atmospheric drag and at other times there might be a lot more. It was the unexpected "wobbliness" of the earth's atmopshere that doomed Skylab in 1979.

Nimby

4,907 posts

157 months

Saturday 4th April 2015
quotequote all
On reflection I think it would take less energy deorbiting. Your mass would be much less without the fuel you'd used getting into orbit.

Flibble

6,487 posts

188 months

Saturday 4th April 2015
quotequote all
Simpo Two said:
I think Planet Earth probably has more pressing things to attend to.

By the way, what would happen to uranium on re-entry? Can it 'burn up' like other metals? If so, are the products of that radioactive too?
Burning up means reacting with oxygen, so you'll get uranium oxides (most likely triuranium octoxide), which as they are largely uranium are indeed radioactive. Effectively you turn it into radioactive ash, aka fallout. wink

You can't remove radioactivity by chemical reactions (such as burning) in general; you have to use a nuclear reaction of some sort.

Mr2Mike

20,143 posts

262 months

Monday 6th April 2015
quotequote all
Simpo Two said:
I think Planet Earth probably has more pressing things to attend to.

By the way, what would happen to uranium on re-entry? Can it 'burn up' like other metals? If so, are the products of that radioactive too?
Google the Russian Kosmos 954 satellite - it broke up on re-entry and spread radioactive material over Canada.

xRIEx

8,180 posts

155 months

Tuesday 7th April 2015
quotequote all
MartG said:
and do we really want to leave nuclear reactors floating around and expect our descendants to sort them out ?
It was sent up 50 years ago; I assume the same people who did that aren't the ones bringing it down so 'their' descendants are sorting it out.

DamienB

1,192 posts

226 months

Tuesday 7th April 2015
quotequote all
We should just nudge it towards the moon. I think it'd make an ideal place to store nuclear waste...

Hooli

32,278 posts

207 months

Tuesday 7th April 2015
quotequote all
DamienB said:
We should just nudge it towards the moon. I think it'd make an ideal place to store nuclear waste...
Only if we get Eagles too.

Mojocvh

16,837 posts

269 months

Thursday 9th April 2015
quotequote all
DamienB said:
We should just nudge it towards the moon. I think it'd make an ideal place to store nuclear waste...
stick in the sun..

Eric Mc

122,861 posts

272 months

Friday 10th April 2015
quotequote all
Very, very difficult thing to do - sending something towards the sun.

MartG

Original Poster:

21,252 posts

211 months

Friday 10th April 2015
quotequote all
Eric Mc said:
Very, very difficult thing to do - sending something towards the sun.
Yes - much easier to go up, safely retrieve the 'hot' bits and deorbit the rest to burn up