Offshoot topic but noting how things we launch from earth already have all the energy they need to orbit the sun, why isn't it really easy to get to earth sun Lagrange points? It seems like we could kind of just float over there since we don't need any additional speed to orbit the sun.
Why the sun is a poor dumping ground for nuclear waste (2010)
121–130 of 176 posts
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#122Use the Jules Verne solution: a cannon. A solar powered mass-driver could sling a steady stream of pellets from Earth orbit into Solar non-orbit using existing technology. That being said, burying it deep near the the start of a plate subduction zone makes at least as much sense.
What does "Solar non-orbit" mean? What would happen, if you managed to make sure all this stuff got escape velocity, is you would wind-up with a bunch of junk (literally) in an orbit around the sun that would inherently pass through Earth's orbit - as long as it doesn't have solar escape velocity, once a thing is moving on pure momentum, it is in orbit and since the orbit fairly closely an ellipse so the object will…
i think he just means any old trajectory that doesn't come back...
its not a completely rubbish idea.
if you shoot the right way you could end up cancelling enough orbital velocity to intersect the sun before any return to earth.
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#123Earlier quoted context omitted.
That "trick" would indeed work and is a well known orbital manoeuvre: http://en.wikipedia.org/wiki/Bi-elliptic_transfer (without the final circularising burn). This manoeuvre would be preferable to the article's alternative (a Hohmann transfer reducing periapsis to the sun's radius without the final circularising burn) in all cases where the initial semi-major axis (relative to the sun) is roughly greater than 11.94…
The downside, of course, is that your nuclear waste spends an awfully long time in an orbit that crosses, or at least passes very close to, Earth's. Better not lose control of your rocket, or you'll have a politically inconvenient situation on your hands.
thats not how this manoeuvre works.
the burn to fall into the sun happens way before any possible return to earth if that orbit were not altered... all that happens is that you start near the earth - thats unavoidable because the rocket comes form the earth.
it will of course cross the earth's orbit on the way into the sun, but, with the exception of very small ranges of orbits the chance of hitting the earth on return is tiny, and easily avoided with some timing.
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#124Earlier quoted context omitted.
> When the Shuttle was first commissioned, my concern at the time was that America's most reliable rocket was the delta, which failed every thirty launches. You were right to be concerned. The shuttle had "a 40% vehicular failure rate and a flight failure rate of 1.5%", killing more people than any other space vehicle. [1] [1] http://www.forbes.com/sites/carolpinchefsky/2012/04/18/5-hor...
And the space shuttles carried many more people than other space vehicles except for the current generation of Soyuz. You don't measure failure rate by number built divided by number crashed. You measure by how much it's used. The more often something is used the more likely it it that it will fail one of those times.
Sure, but the 1.5% flight failure rate is completely unacceptable when you're sending up hundreds of flights with humans on board. Surely, with all the safety precautions that NASA is known for, we'd be targeting a flight failure rate of << 1%.
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#125Use the Jules Verne solution: a cannon. A solar powered mass-driver could sling a steady stream of pellets from Earth orbit into Solar non-orbit using existing technology. That being said, burying it deep near the the start of a plate subduction zone makes at least as much sense.
Given that the past years have "proven" that it's "perfectly safe" to set off hydrogen bombs in the desert; I think it'd be reasonable to assume that it's quite possible to launch a container of junk into space. Not sur why one would care if it hits the sun or not... Iff one can make a container that can survive the blast/lift-off -- one wouldn't need to worry about the launch vehicle exploding in-atmosphere: there'd…
But that would carry the risk of the container filled with nuclear waste colliding with earth at some point in time. And considering there is over 200k tonnes of nuclear wastes, that risk would be a lot larger
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#126I'm not rocket scientist, but it seems like the author is calculating a decreasing spiral into the sun rather than an impact. Why not slingshot around a planet and barrel into the sun with all of the orbital velocity still intact.
he is describing making it fall into the sun directly (if the 'burn' is instantaneous), or if you like, starting to spiral but then just falling in a straight line.
a slingshot changes orbital velocity... thats the whole point. you are right that it is possible to slingshot into an ellipse intersecting the sun... although setting up that manoeuvre itself would be pretty expensive.
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#127Earlier quoted context omitted.
The downside, of course, is that your nuclear waste spends an awfully long time in an orbit that crosses, or at least passes very close to, Earth's. Better not lose control of your rocket, or you'll have a politically inconvenient situation on your hands.
thats not how this manoeuvre works. the burn to fall into the sun happens way before any possible return to earth if that orbit were not altered... all that happens is that you start near the earth - thats unavoidable because the rocket comes form the earth. it will of course cross the earth's orbit on the way into the sun, but, with the exception of very small ranges of orbits the chance of hitting the earth on retu…
I'm aware of how a bielliptic transfer orbit works. See the long gap between burns 1 and 2 on the Wikipedia diagram? That interval is necessarily going to be more than half a year long, and potentially much, much longer. Spacecraft are pretty reliable once they're in space, but that's still a lot of time for something to malfunction. And if burn 2 doesn't happen, now you have tons of nuclear waste on an elliptical orbit that re-visits Earth's path every so often. At any given perihelion, the earth has only a small chance of being in the right part of its orbit, but eventually...
I'm not saying it's a big risk; the chance of a catastrophic launch malfunction is probably a lot greater. But it's definitely a long-term potential hazard that needs to be accounted for.
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#128Offshoot topic but noting how things we launch from earth already have all the energy they need to orbit the sun, why isn't it really easy to get to earth sun Lagrange points? It seems like we could kind of just float over there since we don't need any additional speed to orbit the sun.
You can't just "float over" to another point along your orbit; to move the forward Legrange point you would have to slow down, causing you to drop into a lower orbit which moves around the sun quicker, then speed up to a larger orbit that intersects with the desired Lagrange point and then finally speed up again when you reach that point to stabilize the orbit.
To try this in Kerbal space Program: place two craft into the same equatorial orbit, but with one 1/6th of an orbit ahead of the other. Now make them dock.
It's both counter intuitive and easy once you know how.
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#129I'm not rocket scientist, but it seems like the author is calculating a decreasing spiral into the sun rather than an impact. Why not slingshot around a planet and barrel into the sun with all of the orbital velocity still intact.
Because if the orbital velocity is intact you will perputally miss hitting the sun. The only way you can hit a thing you are orbiting is to remove all the orbital velocity (well, remove enough of the orbital velocity such that your orbit drops low enough to scrape the surface anyway).
its not the only way, its just one way... there are other ways to increase the eccentricity of an orbit - increasing the orbital velocity at the right time, and in a direction that is not radial is less efficient but since the earth's orbit is nearly circular, its not by much.
this is essentially the brute force approach or the bielliptic transfers mentioned in other comments.
Re: Why the sun is a poor dumping ground for nuclear waste (2010)
#130Earlier quoted context omitted.
thats not how this manoeuvre works. the burn to fall into the sun happens way before any possible return to earth if that orbit were not altered... all that happens is that you start near the earth - thats unavoidable because the rocket comes form the earth. it will of course cross the earth's orbit on the way into the sun, but, with the exception of very small ranges of orbits the chance of hitting the earth on retu…
I'm aware of how a bielliptic transfer orbit works. See the long gap between burns 1 and 2 on the Wikipedia diagram? That interval is necessarily going to be more than half a year long, and potentially much, much longer. Spacecraft are pretty reliable once they're in space, but that's still a lot of time for something to malfunction. And if burn 2 doesn't happen, now you have tons of nuclear waste on an elliptical or…
unless burn 1 has a very specific effect that thing is not going to return to earth, despite crossing the orbit. hitting a resonance by accident is pretty unlikely... one could say astronomically so :P
its hard enough to hit things when we want to