What is the most efficient way to send an object to the sun?

[tori]

Actually we talked about 18 kilotons of oxygen. Three orders of magnitude more. And a tactical nuclear bomb as a dispersion charge. Not profitable, not by a longshot

 

[ar81]

There are some satellites that should not be deorbited.
Some have toxic substances that may not burn completely and would cause harm either to people or ecosystems, or you even may have nuclear warheads in satellites that are no longer working.

My bet is those should be sent to the sun. Also, nuclear waste could be sent to the sun.

Reuters: Obama, politics and nuclear waste

So then what? Start from scratch? Perhaps a return to the dawn of the nuclear age? The options under discussion then included burying radioactive material in the ocean floor, placing it in polar ice sheets — and even blasting it into space.

If it was up to me, I'd send that waste to the sun. In the long term is cheaper than building underground nuclear waste storage facilities, provide maintenance, and then lose the chance to use that land for other economic activities.

 

[Eagle]

How is the solar sail not mentioned here? The only rockets required are to put it into a high enough orbit where air resistance won't crash it back to earth faster than the sail can accelerate.

After that the only fuel required is a reaction system to despin the gyros.

 

[Sky Captain]

If it was up to me, I'd send that waste to the sun. In the long term is cheaper than building underground nuclear waste storage facilities, provide maintenance, and then lose the chance to use that land for other economic activities.

That would be a waste of valuable resource since the "waste" contains over 95% of unfissioned uranium and the rest is fission products and various isotopes some of which are useful in medicine and industry. Ordinary light water reactors release only few percent of total energy thats inside uranium. It would be much better to reprocess the spent fuel to seperate the useful isotopes from uranium. That uranium could later be used into breeder reactors to generate power.

 

[Adelanthal]

But Ark, you've first got to put up ISPV-7 and, at least, Toy Box. Granted, we might get access to Van Braun...

 

[martins]

Also remember that anything dropped into the sun that is heavier than hydrogen will accelerate her demise - (by seconds?)

 

[Urwumpe]

Also remember that anything dropped into the sun that is heavier than hydrogen will accelerate her demise - (by seconds?)

Rather by picoseconds per kg, when looking at the current metallicity of the sun. Iron should have stronger effects than carbon. If we dump enough material into the sun, we could even push it beyond the Chandrasekhar limit before the end of the fusion processes.

 

[ar81]

So what should be the final effect on the sun if we dump all our waste there?

 

[Artlav]

So what should be the final effect on the sun if we dump all our waste there?

Zilch.
We can dump our planet in there without much effect.

 

[Bj]

So what should be the final effect on the sun if we dump all our waste there?

A big huge hydrogen bomb? :lol:

Seriously, I have no idea but instead of the sun, why not Venus or something? It is a little closer so the booster doesn't have to spend so much time on a single payload.

 

[Urwumpe]

We can dump our planet in there without much effect.

It should have an effect - but no instant stellar death. The sun is only 332,900 times heavier than Earth.

http://en.wikipedia.org/wiki/Metallicity#Calculation

Even dumping earth into the sun wouldn't raise its metallicity by 0.0001.

But what I can't find yet, is the metallicity at which a main sequence star starts to become a red giant.

 

[ar81]

My uninformed guess is that even if we dumped the entire waste this planet could ever produce we wouldn't make it go red giant. Am I wrong?

Going back to the original question. It seems to me that Earth retrograde is the best direction to get out from SOI, but should it be going in outer or inner system direction when ejecting?

 

[Eagle]

Rather by picoseconds per kg, when looking at the current metallicity of the sun. Iron should have stronger effects than carbon. If we dump enough material into the sun, we could even push it beyond the Chandrasekhar limit before the end of the fusion processes.

Not really. The hydrostatic pressure just from the heat of the sun would keep the core from collapsing for millennia. Supernovae happen when the cores of supergiants cool enough to collapse.

 

[Urwumpe]

Not really. The hydrostatic pressure just from the heat of the sun would keep the core from collapsing for millennia. Supernovae happen when the cores of supergiants cool enough to collapse.

No, that is partially wrong. The cores don't cool down (in first place), the radiation pressure by the reduced number of fusion processes is not enough for countering gravity. The cores of a star can remain very hot for billions of years, because of the electron-degeneracy, that keeps white dwarfs stable.

Also, red giants don't have fusion processes in the core anymore, but in an layer just outside the core. That outward motion of the fusion region is what causes a main sequence star to expand.

The Chandrasekhar limit is also not the mass at which a star instantly collapses, but at which a star becomes a neutron star instead of a white dwarf. (Chandrasekhar limit = maximum mass that can have gravitational collapse prevented by electron degeneracy pressure)

 

[ar81]

Do you think using the moon going retrograde to slingshot towards sun may work with a low thrust engine?

 

[ar81]

Well, it seems that my idea of VASIMR being usable to drop junk on the sun may actually be possible. If I am not wrong, the DeltaV for Hohmann transfer from LEO to the sun would be near 30,000,000 m/s according to IMFD. Is that correct?

 

[Mogeley]

you'd spend less energy building a recycling plant on the moon, maintaining it, and flying junk to it than the energy required to actually hit the sun.

Your delta-V to hit the sun is roughly 30,000 m/s - orbital velocity.

Besides once you throw it in the sun it's gone. If you recycle it then you can move towards a low G shipyard on the moon...

Or if you don't like the moon, create a sub-geosynchronous (slower than geosynchronous) junk yard to slowly float junk to. Either way you'll have all sorts of orbits to collect junk in and massive plane changes will use most of your fuel.

---------- Post added at 12:55 PM ---------- Previous post was at 12:42 PM ----------

It would be interesting to try to hit the sun... If you were off just a little bit and missed the sun, then you'd create a nice man made object for the earth to one day hit a few years later.

Either way. I'd want a small guidance package on the the trash to keep it from getting into an orbit that may hit the earth.

 

[T.Neo]

Throwing stuff into the sun is a bit expensive and destructive, methinks. A lot of things like nuclear waste could actually become very valuable.

For stuff in LEO, controlled deorbit into the ocean should suffice. For other stuff, towing to some sort of orbital recycling plant or interplanetary trash bin could work.

But interplanetary space is pretty empty, the only reason you'd want to clean up our junk from that is for recycling purposes.

 

[RisingFury]

My best guess for "cheapest" approach to the Sun would be to shoot up as high as half the Saturn's orbit, then swing past Jupiter on your downward part of the journey. If you pass "in front" of Jupiter (front defined as direction of motion), then Jupiter's gravity will bend your orbit further down, towards the Sun. Be careful not to get ejected out of the Solar system though. Happens quickly, when you're messing around Jupiter.

 

[ar81]

With a VASIMR engine, trajectory becomes a spiral, becuase of its low thrust.
See this doc.