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Tain
June 4th, 2005, 12:57 AM
"NASA's primary research program for developing these technologies is Prometheus Nuclear Systems and Technology. Named for the ancient Greek god of fire and craft, Prometheus has two initial objectives:

1. To develop nuclear-powered propulsion systems
2. To build Prometheus 1, a spacecraft that could conduct far-reaching,long-lasting exploration missions."



http://www.nasa.gov/vision/universe/features/nep_prometheus.html

Agent_Dark
June 4th, 2005, 01:16 AM
Pfft, get with the times NASA - Prometheus is built already and kicking arse out there ;)

_Owen_
June 4th, 2005, 10:20 AM
Ya, I think that they should keep NASA a little furthur in the loop.

lol, seriously, I don't think it is such a big coincidence. Names from mythology are being used for ships all of the time, Prometheus was bound to come up sooner or later.

Owen Macri

Seastallion
June 4th, 2005, 10:32 AM
I've heard some scientist are a little annoyed with sci-fi movies and tv... because the stuff they show on there far exceeds anything we're capable of and the scientist feel it makes the publics expectations of scientific and technological progress too high. In other words, we see space shuttles the size of mini-vans on Star Trek doing things a big Space shuttle in real life couldn't ever dream of doing. *cries* It isn't fair... I wish I was born a thousand years in the future, with all the cool tech around... Hmmm... but they say we always want things we can't have... maybe if I were born in the future I'd want to live a primitive life, like now... ??? Who knows... :p LOL

immhotep
June 4th, 2005, 10:45 AM
wow sounds promising.........whens the daedalus coming out!

Jarnin
June 4th, 2005, 12:52 PM
I've heard some scientist are a little annoyed with sci-fi movies and tv... because the stuff they show on there far exceeds anything we're capable of and the scientist feel it makes the publics expectations of scientific and technological progress too high.
This really is a problem. People are so used to turning on their television and watching star trek. Anything we can do in real life is boring to them unless it involves warp speed and photon torpedos.

Another problem is that most people don't even know what is out there. I mean, everyone knows about the nine planets, but how many people realize there are over 90 "worlds" that people could actually live on right in our own solar system?

In the end however, Prometheus is just hand waving. I mean, the technical part of it is completely doable, it's just that it won't ever get anywhere soon. President Bush has already cut it's funding for 2006 to make room for his return to the moon mission, and if we're going to the moon, we don't need nuclear powered spacecraft; chemical rockets work just fine for such a short hop.

The only time you need a nuclear propulsion system is when you're doing extended trips, like to Jupiter and farther out. Anything out that far receives far less sunlight than we get here, so nuclear is the way to go. Cassini, the probe that recently made it to Saturn, is nuclear powered which freaked a bunch of people out.
I remember when Cassini was launched, there were a bunch of protesters saying the world would end if the rocket exploded. Little did they know that the RTGs that NASA use are specifically designed to survive through a rocket explosions so they can be reused! But the media didn't cover the specs of the RTG, they covered the treehuggers saying the sky was falling.

When people stop seeing mushroom clouds each time the word "nuclear" is spoken, then you'll see things like Prometheus in space. Until then, it's all political hand waving.

6thMonolith
June 4th, 2005, 03:42 PM
Nice post. We still do have a few missions coming up, but nothing way too drastic.
( http://www.nasa.gov/missions/highlights/schedule.html ).


When people stop seeing mushroom clouds each time the word "nuclear" is spoken, then you'll see things like Prometheus in space. Until then, it's all political hand waving.

Too true. Even nuclear-powered aircraft carriers don't work off a mushroom cloud, they run off steam.

Seastallion
June 4th, 2005, 04:26 PM
This really is a problem. People are so used to turning on their television and watching star trek. Anything we can do in real life is boring to them unless it involves warp speed and photon torpedos.

Another problem is that most people don't even know what is out there. I mean, everyone knows about the nine planets, but how many people realize there are over 90 "worlds" that people could actually live on right in our own solar system?

In the end however, Prometheus is just hand waving. I mean, the technical part of it is completely doable, it's just that it won't ever get anywhere soon. President Bush has already cut it's funding for 2006 to make room for his return to the moon mission, and if we're going to the moon, we don't need nuclear powered spacecraft; chemical rockets work just fine for such a short hop.

The only time you need a nuclear propulsion system is when you're doing extended trips, like to Jupiter and farther out. Anything out that far receives far less sunlight than we get here, so nuclear is the way to go. Cassini, the probe that recently made it to Saturn, is nuclear powered which freaked a bunch of people out.
I remember when Cassini was launched, there were a bunch of protesters saying the world would end if the rocket exploded. Little did they know that the RTGs that NASA use are specifically designed to survive through a rocket explosions so they can be reused! But the media didn't cover the specs of the RTG, they covered the treehuggers saying the sky was falling.

When people stop seeing mushroom clouds each time the word "nuclear" is spoken, then you'll see things like Prometheus in space. Until then, it's all political hand waving.

I agree... the anti-nuke people really get on my nerves. There is some nuclear technology that is very useful, and not necessarily a big bruise on the ecology. I think our country should use more nuclear power. Of course I'm concerned about radiation and stuff, but there are safer ways of doing it. I really do believe we need to get serious about Fusion reactors. They'll never get off the ground if the government, or someone doesn't put some serious backing into it. Mining the moon for Helium-3 which could be extremely valuable if we can figure out the whole Fusion thing. Helium-3 is very rare here on Earth, but there appears to be a lot more of it on the moon. I think that the USA should put some serious backing into the aerospace industry, and also if possible, we should build a space-elevator. Or many. I really do think that with nano-tubes it could be done, and it would make getting to space much easier and far cheaper. :D

Odin's eyes
June 4th, 2005, 05:20 PM
Uhm... we can already build a fusion reactor that creates energy.
The only thing holding us back is where we're going to build the first experimant reactor.
The EU, Russia and China want to build it in the south of France and the US and Japan wants it to be in Japan.
Right now it seems like it will end up in France because the EU has stated they don't want to wait anymore and will fund it alone if Japan and the US won't agree to place the fusion reactor in France.
As always, politics is what keeps us from making progress. Isn't it always so? ;)

I'm somewhat against nuclear power myself since we can build enough wind power plants to power the entire world community right now.
There's a scientist in the US that has done some research on this and picked out 8000 places in the world that would be suitable for wind power. We only need to build out wind power on 10% of those places to cover the need of the entire world. Think about that. :)

But nuclear power in space I'm all for. Once we get into deep space any explosion of a nuclear powered vessel won't even be noticed in terms of radiation. Space is very big...:D

_Owen_
June 4th, 2005, 09:25 PM
I've heard some scientist are a little annoyed with sci-fi movies and tv... because the stuff they show on there far exceeds anything we're capable of and the scientist feel it makes the publics expectations of scientific and technological progress too high. In other words, we see space shuttles the size of mini-vans on Star Trek doing things a big Space shuttle in real life couldn't ever dream of doing. *cries* It isn't fair... I wish I was born a thousand years in the future, with all the cool tech around... Hmmm... but they say we always want things we can't have... maybe if I were born in the future I'd want to live a primitive life, like now... ??? Who knows... :p LOL
The only problem is, if you were born in the future, everything there would be commonplace. The most advanced technology would be available for everyday use, something that would seem ingenious to us, is normall for them. If you were born in the future, the only thing that you would want is to be born even farther in the future. Trust me, I have thought this through. I think a lot of little kids see science fiction on T.V. and compare it to real life, and then say, "Well, damn it, why did I have to be born now, why couldn't I have been born a billion years in the future," I was one of those little kids.

Owen Macri

Seastallion
June 4th, 2005, 11:50 PM
The only problem is, if you were born in the future, everything there would be commonplace. The most advanced technology would be available for everyday use, something that would seem ingenious to us, is normall for them. If you were born in the future, the only thing that you would want is to be born even farther in the future. Trust me, I have thought this through. I think a lot of little kids see science fiction on T.V. and compare it to real life, and then say, "Well, damn it, why did I have to be born now, why couldn't I have been born a billion years in the future," I was one of those little kids.

Owen Macri

LOL... :p Pssshhh! What are you talking about...??? :rolleyes: Your STILL a kid..! I'm 27 years old, believe me I've thought as much, and very likely more than you about it. I'm nearly twice your age, and am well aware of what you speak of. As I said in my previous post... it is human nature to desire that which we do not have. Which is basically the exact same thing you just said. So, see? I do know what I'm talking about. :p Trust me... :rolleyes:

I don't mean to rip you or anything... but I would hope that by now, you'd give me a little credit for knowing a thing or two. ;) I know it wasn't your intention, but you implied I was one of those "little kids"... and you well know I'm not. Actually... the truth is, we've ALL been those little kids at some point or another. I don't mean to lecture, but I must ask you not to do the same to me. :) ...or at least don't call me a little kid. :p LOL Peace, my friend..! ;)

_Owen_
June 5th, 2005, 05:59 AM
Oh, I am sorry, I didn't see that in your post.

As for the little kid thing, I know that you aren't a little kid, I know that I am not a little kid, I was trying to say that at one point in time, when we were little kids, many of us did think about wanting to be born in the future instead of now. I appoligize if I offended you that was not my intention.

I wasn't implying that you are a little kid, I was implying that just like everyone else on this planet, you were a little kid, and to top that off you might have been the same kind of little kid as me, dreaming about the future at every opportunity...

Owen Macri

Jarnin
June 5th, 2005, 01:38 PM
Uhm... we can already build a fusion reactor that creates energy.
The only thing holding us back is where we're going to build the first experimant reactor.
The EU, Russia and China want to build it in the south of France and the US and Japan wants it to be in Japan.
Right now it seems like it will end up in France because the EU has stated they don't want to wait anymore and will fund it alone if Japan and the US won't agree to place the fusion reactor in France.
As always, politics is what keeps us from making progress. Isn't it always so?
Yes, it is always so.

France is currently sitting at about 10% unemployment, so they want to have that money spent in France to pay French workers to build ITER. France currently has about 75% of their electricity generated by fission reactors, so they have plenty of power.
Japan doesn't have the problem with unemployment; they simply don't have any reserves of petroleum or coal in Japan. They have to rely on fission for about 30% of their power, with the rest made up by spending billions having oil imported to their country.

Even if they agreed on a site today, it'd still probably be 50 to 100 years before fusion would become commonly used. What do we do in the meantime?


I'm somewhat against nuclear power myself since we can build enough wind power plants to power the entire world community right now.
There's a scientist in the US that has done some research on this and picked out 8000 places in the world that would be suitable for wind power. We only need to build out wind power on 10% of those places to cover the need of the entire world. Think about that. :)
While it might be possible to power the entire world with wind mills, there is always the problem that it's not always windy everywhere. You end up with large fields of wind mills in windy places, and then you have to distribute that electricty to the people who will use it where it's not windy.
That means building a huge distribution system, which means you have to relay and boost it along the way. If you build the farms closer to the people that will use it, you have the problem of noise and seeing a bunch of wind mills every time you look around. Wind mills are also famous for killing birds, which has environmentalists up in arms.

As it turns out, nuclear power is very efficient in just about every corner of the world, and it's environmental impact is quite small. People like to point out that meltdowns would increase its impact, but reactor technology has come to the point where many designs are incapable of melting down.
The only downside to nuclear power is the waste generated, which is orders of magnitude less than your average coal burning electrical plant, and the thing is, nuclear waste is contained while coal spews its waste directly into the air. Did you know that coal burning plants spew up to 25 tons of uranium and other radioactive elements into the air each year? I wouldn't want to live downwind from that.

There is no single solution to power production. Every solution has downsides that make using them impractical in many cases. We're going to have to use wind, solar, tidal, geothermal and nuclear in places where those solutions will work most efficiently and have the least impact on the environment.

Seastallion
June 5th, 2005, 01:52 PM
Oh, I am sorry, I didn't see that in your post.

As for the little kid thing, I know that you aren't a little kid, I know that I am not a little kid, I was trying to say that at one point in time, when we were little kids, many of us did think about wanting to be born in the future instead of now. I appoligize if I offended you that was not my intention.

I wasn't implying that you are a little kid, I was implying that just like everyone else on this planet, you were a little kid, and to top that off you might have been the same kind of little kid as me, dreaming about the future at every opportunity...

Owen Macri

:p I was just messing with you... ;) Don't take it too seriously. I know pretty much what you meant, I was just poking a little fun at your expense. Try never to take anything too seriously... it gives you heartburn... :p LOL I know you weren't calling me a little kid, (not really) I just used the possible implication (however remote) to take a little jab at ya... :D If it makes you feel better... I sort of am like a big kid. Sort of. I'd rather play than work... so I guess that makes me still a kid. :p

sharky277
June 5th, 2005, 03:13 PM
This is a better link...

http://prometheus.jpl.nasa.gov/index.cfm

_Owen_
June 5th, 2005, 03:49 PM
Oh, that's ok, I had a feeling that you might be joking, but I didn't know if you were actually serious. lol.

In response to sharky277, that is a very good link I will check it out in detail when I have a second.

Owen Macri

6thMonolith
June 5th, 2005, 05:46 PM
This is a better link...

http://prometheus.jpl.nasa.gov/index.cfm

I found that site when I was bored, a few weeks ago(so I wasn't surprised when this thread started). I always check http://saturn.jpl.nasa.gov for updates. They have some pretty nice pics of saturn/titan that I use for desktops.

_Owen_
June 5th, 2005, 05:58 PM
Cool!

Owen Macri

Avatar28
June 5th, 2005, 06:12 PM
It's not just trips to Jupiter where nuclear would be important. For ANY serious interplanetary manned mission, nuclear is the way to go. For a sizeable manned mission to Mars, they're going to want to have a nuclear reactor on board for power. Furthermore, there are several nuclear based options for propulsion that would allow for much greater efficiencies and higher speeds if we were to seriously pursue it.

The best possible course would be some sort of Orion drive variant. Look it up if you want more info on it, but basically the idea is that you have a ship with a pusher plate mounted on large shock absorbers. You set of a nuclear explosion next to the plate. The force of the explosion pushes the plate (and thus the ship) forward. Repeat. You do this fairly rapidly and you get a good acceleration.

The best thing about an Orion drive is that the thrust is incredibly high, in the MILLIONS of TONS. By comparison, the huge SRBs on the shuttle only offer around 2 million LBS of thrust. An Orion drive would allow for some truly incredibly massive ships. It would be no trouble at all to have a ship two to three times larger than an modern naval aircraft carrier if you wished.

Unfortunately, due to the nuclear test ban treaty, and the political climate, setting off lots of nukes (even small ones) in space isn't likely to occur in the near future.

Our true best bet in the near term (say the next two to three decades) is probably going to be VASIMR. It's a plasma drive and is throttleable between high efficiencey and high thrust. Basically it uses microwaves to heat a hydrogen plasma to several million degrees Kelvin and this plasma is used for thrust. It may be possible to even add a fusion component into the drive which would GREATLY increase the thrust it can produce even further. A full scale VASIMR drive would be able to use a "low gear" high thrust, low efficiency mode to climb out of the gravity well of a planet and break orbit towards interplanetary space. At that point it switches into "high gear," lower thrust big very high efficiency. At the moment, unfortunately, the thrust levels are still far too low to be able to actually go from surface to orbit so you're still stuck with chemical rockets or some other form of propusion for that.

_Owen_
June 5th, 2005, 06:17 PM
In space size does not matter, a nuclear reaction would push a ship twenty times earth just as far as it would push my pen. You know, if it didn't completly destroy it first, lol.

Owen Macri

Avatar28
June 5th, 2005, 06:29 PM
Mass still matters in space. The more something weighs, the more power it takes to change the velocity a given amount.

_Owen_
June 5th, 2005, 06:34 PM
There is no weight in space other than the very small amount when you are within a gravitational field, but it is only a miniscule amount of wieght. So weight would not matter in space either.

Owen Macri

6thMonolith
June 5th, 2005, 07:01 PM
Weight is not an issue, but inertia is.

_Owen_
June 5th, 2005, 07:03 PM
Yes, but without gravity or friction the inertia of a large object and a smal object propeled by the same force would be the same. It is a common mistake in shows like Star Trek, when they are trying to move something with their tractor beams and they aren't strong enough to move them.

EDIT: Newtons' First Law, Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

So a ship for example in space, at rest, will remain at rest, unless effected by another force like a tractor beam or more specifically kinetic energy. Normally this force would be weakend by other forces such as gravity and friction however in space these do not apply, unless in a unique circumstance like is the object is effected immensly by a gravitational field or there is constant friction against the object.

Owen Macri

Odin's eyes
June 5th, 2005, 07:57 PM
There is no single solution to power production. Every solution has downsides that make using them impractical in many cases. We're going to have to use wind, solar, tidal, geothermal and nuclear in places where those solutions will work most efficiently and have the least impact on the environment.

Cut your post down a bit so I won't take up so much space. :)

Jarnin, I'm not suggesting that we should only build wind power. :)
There's lots of great alternatives to what we have today.

Nuclear power in the western nations is safe, yes. There's a lot of safe guards against a melt down. But I'm a bit more concerned about those in the old Sovjet Union...
And the waste... I'll come to that later.

Yes, solar power is one way to go but it takes up too much land acres to be viable for anything truly large scale. Nations that has deserts are the ones that can use solar power at it's best since they really don't have a problem with finding space or worry about if the sun will shine or not.

Geothermal... again, it's good, but only for some nations. You really have to be near the edges of the continental plates to get some major power from it.
(Closer down to get enough heat) Island would be the best example of this since they already get all their power from geothermal powerplants. For nations that are far away from the continental plates the potential is not so good. Sure, you can heat up your own house but it's too expensive to dig deep enough for a geothermal power plant.

Tidal power? Never going to be more then a minor part in any nations power supply, even if they do make it to work so it can generate more power then today. I simply don't see it generating enough power compared to what other options can do.

Wave power: Scientists have for years tried to harness the power of the waves. Not very successfully I might add... :p But now there's some movement on that front that looks promising. A swedish team will set out a few wave power generators sometime next year. If they simply buildt... I think 10 acres (I just forgot the exact number :( ) of those wave power generators it would generate enough power for Sweden.
Mind you that there really isn't so many high waves along the swedish shores so if you placed them in the North Sea instead they would generate many times more then that.
There's also plans to try and build something akin to a wind turbine that would instead tap into the power of underwater currents, such as the Gulf stream. Major potential there...
Of course the wave power option and the underwater currents turbines won't happen for another 15 or 20 years. But we can hope... :)


And now I return to the nuclear waste...

Until something better then nuclear power comes up to replace it the EU, lead by France is throwing large amounts of money into research on transmutation. The goal there is to in the end make the nuclear waste a lot safer and instead of keeping it locked away for 100's of thousands of years until it's safe, it will only take about 1000 years.
It's this whole proccess of taking out the uranium from the waste and re-using it. I'm not too clear on the details as I've only heard very little on this.

All my info comes mainly from swedish news sources so I may not have the full truth on all of these issues. I'm sure somone will correct me if I'm wrong about something. :P

I think that was the longest post I've ever made... :D

_Owen_
June 5th, 2005, 08:12 PM
Lol, that was a good post, as for the nuclear waste idea, it has potential but as of now we don't really have the technology to properly extract and utilise the uranium in large amounts in nuclear waste. Trying to extract and reuse it is like buring a log picking up all of the ashes putting them together and buring them to accomplish a source of heat and light energy. It is far easier to just go and use another log, or in this case fresh uranium, however this is wasteful when you do technically have uranium that hasn't been used yet that can be reused.

I guess what I am saying is the concept is a smart one, however it would take a while to complete the procces. If we could develop a faster way it might be more efficient.

Owen Macri

Avatar28
June 6th, 2005, 03:35 PM
Actually, we only use a small amount of the fuel anyways. But the concept (and the technology) actually works today with reactors that are designed for it. I'm not sure what would be involved in retrofitting a reactor to do it that wasn't designed for it.

Fusion on a large scale, especially He3 fusion, would be the ideal answer. No possibility of meltdown and very very little radioactive waste.

Jarnin
June 6th, 2005, 04:55 PM
Yes, solar power is one way to go but it takes up too much land acres to be viable for anything truly large scale. Nations that has deserts are the ones that can use solar power at it's best since they really don't have a problem with finding space or worry about if the sun will shine or not.
People used to say the same thing about telephones. You have to wire the world or else it won't work everywhere. Then Arthur C. Clarke invented the communication satellite, and now we have global communications.

Read up on Space Solar Power (http://www.space.com/opinionscolumns/opinions/glaser_000223.html).


Until something better then nuclear power comes up to replace it the EU, lead by France is throwing large amounts of money into research on transmutation. The goal there is to in the end make the nuclear waste a lot safer and instead of keeping it locked away for 100's of thousands of years until it's safe, it will only take about 1000 years.
It's this whole proccess of taking out the uranium from the waste and re-using it. I'm not too clear on the details as I've only heard very little on this.
Transmutation (http://en.wikipedia.org/wiki/Transmutation) is a good way to deal with the waste. It uses spent fuel and turns it into an isotope that doesn't have such a long halflife. There are actually reactor designs that burn nuclear waste and whose products last for less than 30 years. Integral Fast Reactor (http://en.wikipedia.org/wiki/Integral_Fast_Reactor) designs allow you to never have the waste leave the plant; it's used until it's no longer radioactive.

Even without recycling, storing waste in glass blocks and burying it in a geologically stable environment is a better alternative to spewing waste into the air.

_Owen_
June 6th, 2005, 05:11 PM
Nice post Jarnin!



Even without recycling, storing waste in glass blocks and burying it in a geologically stable environment is a better alternative to spewing waste into the air.

Really?!? You aren't stating the obvious at all! (Sarcastically) lol!

Seriously though I agree.

Owen Macri

Avatar28
June 6th, 2005, 07:46 PM
I'd rather have a nuke plant in my town than coal any day. Coal plants release FAR FAR more radiation into the environment than a nuke plant. In fact, you would generally receive a lower radiation dose INSIDE a nuclear plant than you would standing around outside far away from it.

Space based power production is great in theory. But launch costs are still far too prohibitive. Those would first have to come way down. Any really significant solar power station would need to be kilometers long. That's going to amount to a fair bit of weight no matter how you scale it.

Now if we were to build a space elevator then that would definitely drop costs to the point that we could probably build something like that and have it competitive. It would also enable us to quite easily launch interplanetary missions and put much larger payloads and have larger ships.

Sir Arthur C. Clarke once predicted that a space elevator would be built about a decade after people stopped laughing. Guess what? People are stopping laughing about it.

_Owen_
June 6th, 2005, 07:54 PM
Actually they have been considering a elevator. In theory it is not a difficult concept, and it would provide many options as well as more generalized space travel, more public space travel...

Owen Macri

Avatar28
June 6th, 2005, 07:57 PM
Oh, I'm all ABOUT a space elevator. LOL. If I had the money, I'd build one myself. The amazing thing is that it could probably be done for only a few billion dollars, bureaucracy and red tape notwithstanding (I expect that would increase the cost substantially). Basically, you only need to launch enough materials to build a very small strand down to the surface. Once there, the filament can be expanded on to bring it to it's full size and strength.

And, yes, it would allow public access to space eventually, once more cables are strung to allow more simultaneous up/down trips, it should become much easier.

Your main building costs are just land and materials (and the initial launch of 20 tons to geosync orbit).

_Owen_
June 6th, 2005, 08:11 PM
Yes, and the, I guess you could call it a space anchor, would need to be in such an orbit around the Earth so that the pull of the anchor away from the Earth is equal or greater to/than the force that will be pulling against it. The only problem is the location of this elevator would need to be carfully sighted out because no planes or arial vehicles would be permitted in the area. As well the orbit would have to calculated properly so that it would not accidentally hit any satelites, etc.

Technically the space elevator is a logical idea with our current technology, I would definetly make one if I had the money, who knows maybe someday I will...

Owen Macri

Avatar28
June 6th, 2005, 08:16 PM
It would have to be located on the equator somewhere. A.C. Clarke propsed Sri Lanka in Foundations of Paradise. Other than that, any location right on the equator would be good, but something in the middle of the ocean would be ideal since you'd have less air traffic to contend with. Impacts by space junk in LEO would be the real threat though anyways.

_Owen_
June 6th, 2005, 08:22 PM
I would have thought maybe a large desert, you wouldn't get much air traffic there, but where would here be a plausible location? I agree, get rid of the space junk, maybe they could put some weapons on it, nothing big just enough to blow up and nasty little rocks. lol.

Owen Macri

Avatar28
June 6th, 2005, 08:37 PM
Problem with that is that you end up with lots of little junk which can be just as bad and is a LOT harder to clean up. At least the bigger stuff can be more easily deorbited. Nukes are no go because of the EMP effect would do a LOT of damage.

_Owen_
June 6th, 2005, 08:39 PM
I guess that is true, how about some type of overload laser to melt the space junk? Then you would pretty much get rid of it.

Owen Macri

Avatar28
June 6th, 2005, 08:57 PM
Hmm, maybe but high powered lasers aren't exactly common or efficient right now. And you still have to find it. Also the laser would still be more likely to cause it to explode or burn a hole through it than to melt the whole thing. Some of the really big stuff could possibly be collected and brought back down or even simply deorbited to burn up in the atmosphere. That's what they typically do with old satellites. Most stuff in LEO will do that anyways without periodic boosts due to atmospheric drag. That's why the space station has to be pushed back up every so often. Also most middle to larger sized stuff can be tracked by radar and possibly collected or diverted. It's the smaller stuff that will cause the problems.

cobraR478
June 6th, 2005, 09:46 PM
There is no weight in space other than the very small amount when you are within a gravitational field, but it is only a miniscule amount of wieght. So weight would not matter in space either.

Owen Macri
Its not the weight he is actually talking about, its the mass. A rocket wold not propell the Earth, or the moon, as much as it would propell a pen.

_Owen_
June 7th, 2005, 01:28 PM
The reason that I rocket would not propel the Earth or the moon is because they are strongly effected by other gravitational fields.

The only thing that will counteract momentum is gravity and friction, a ship is space would not be largley effected by any gravitational field unless in an orbit, and there is no constant friction in space except for contact with another spatial body.

If the Earth was placed somewhere so it would be uneffected largley by a gravitational field like in a void between galaxies, then a rocket would propel the Earth and the moon and a pen, the same distance.

Owen Macri

Avatar28
June 7th, 2005, 02:41 PM
Sorry, Owen. That's where you're wrong. The more massive an object is, the more force it takes to move it. It has nothing to do with it being in a gravitational field. Also, even if an object were in the void between galaxies, it would still be affected by the gravity of said galaxies.

What counteracts momentum is a FORCE. And that's what thrust is, a force. The more massive it is, the more force it take to overcome it's inertia and effect a change. Say you've got two weights. One is 1 lb and one is 2 lbs. If you apply the same impulse to both objects (meaning each received the same amount of energy), the 1 lb object will be end up moving twice as fast as the 2 lb object due to conservation of momentum.

_Owen_
June 7th, 2005, 06:49 PM
The reason that you are using this line of thinking is because you are using examples from Earth, correct me if this is incorrect and you are thinking diffrently.

The reason that two objects on Earth of diffrent size could not be propeld equal distance is because:

1) The mass of object one is larger than the mass of object two, so it will be pulled towards Earths' surface faster because it is heavier.

2) The greater the mass of the object the more friction is acting on it, friction from the air around it.

For the sake of argument let's say for example that the two objects are cubes, simply to not make things more complicated than they need to be by brining in aerodynamics as well.

On Earth the cubes will be propeled diffrent distances when the same amount of force is applied, however in space when not in a significant orbit around another spatial body the two objects will be propeled the same distance at the same speed.

The factor of gravity would not be working significantly on the objects, and the factor of the constant friction of air on the objects would not be acting on the experiment at all.

In space not orbiting a spatial body or being attracted at a siginificant rate by a spatial body, the objects will be virtually wieghtless, not completly, but very close.

Two cubes of diffrent sizes fired from the same position in space where friction and gravity are not forces that are significantly working on them would travel the same distance at the same speed when proppeld by the same force.

I agree with you, mass does have an impact on the amount of force required and the distance the object will travel but mass only has a large impact when it is being effected significantly by gravity. Thus the force effecting the objects siginificantly is actually gravity, and the property of the object that is causing it to effected by gravity is its' mass, when the amount of mass is effected by gravity it gives the objects weight.

Now I admit in our universe there is always gravity acting on objects, this comes from Netwonian Physics every object in the universe will attract every other.

I agree if there is a gravitational field in effect then the objects will not travel the same distance or travel at the same speed however the wieght diffrence of the two objects that we would be talking about would be incredibly miniscule.

If the Earth was placed in the galactic void, not in any orbit, simply "dead in space" its' weight would be incredibly minicule, and the pens' weight would be even less, but the diffrence between the two would be incredibly small, when a large objects' wieght is nearing 0 in whatever unit of measurment you want to use, having zero as the neutral point of the measurmeant system, a significantly smaller item like a pen would have a smaller weight but not a significant weight diffrence. Therfore the pen and the Earth would travel at close speeds, not exactly the same speeds but close.

The reason that you can't push a twenty billion pound weight on Earth is because of gravity its' weight is simply to great, but in space that same twenty billion pound weight would be incredibly easy to push if you had something to push against.

However I was not disputing the fact that in an unisolated system two units of matter will not travel at diffrent speeds when fired from the same point with the same amount of force.

Owen Macri

cobraR478
June 7th, 2005, 10:22 PM
No, mass has a HUGE impact on a rocket's ability to move something, even in space. Especially when comparing a pen to a planet. A Saturn V rocket would easily move a pen, or a team of 3 astronauts, but would have a negligible effect on a planet, or any other large body.

Avatar28
June 7th, 2005, 10:23 PM
The reason that you are using this line of thinking is because you are using examples from Earth, correct me if this is incorrect and you are thinking diffrently.

No. The information I'm giving you is basic physics and has nothing to do with it being on earth or not. The rules are the same regardless.


The reason that two objects on Earth of diffrent size could not be propeld equal distance is because:

1) The mass of object one is larger than the mass of object two, so it will be pulled towards Earths' surface faster because it is heavier.


Wrong. The mass of the object has absolutely nothing to do with the rate at which they fall. Other factors such as air resistance can affect it, but in a vacuum, all objects would fall at the same rate regardless of their mass. This was proven during the Apollo missions when an astronaut dropped a feather and a hammer and both hit the surface at the same time.



2) The greater the mass of the object the more friction is acting on it, friction from the air around it.

No, the mass of the object has nothing to do with the resistance of the air it's moving through. Surface area and aerodynamics is your primary factor here.


For the sake of argument let's say for example that the two objects are cubes, simply to not make things more complicated than they need to be by brining in aerodynamics as well.

On Earth the cubes will be propeled diffrent distances when the same amount of force is applied, however in space when not in a significant orbit around another spatial body the two objects will be propeled the same distance at the same speed.

Being in orbit or not really has no real affect on this. With no friction (say in orbit above the atmosphere), both objects would keep going forever until another force acts on them. This is Newton's first law and is also known as inertia. Basically that an object will resist a change in motion. We'll address the implications of this in a bit.



The factor of gravity would not be working significantly on the objects, and the factor of the constant friction of air on the objects would not be acting on the experiment at all.

In space not orbiting a spatial body or being attracted at a siginificant rate by a spatial body, the objects will be virtually wieghtless, not completly, but very close.


Gravity is irrelevant for this discussion. And you are correct that they would be virtually weightless. But NOT massless. Weight is not the same thing as mass. Weight is a result of mass under the influence of gravity but is not an inherent property of an object. Mass is. ALL matter has mass (and I believe that some current thinking is that even energy can have mass) regardless of the presence of gravity (which you can also never truly escape from).



Two cubes of diffrent sizes fired from the same position in space where friction and gravity are not forces that are significantly working on them would travel the same distance at the same speed when proppeld by the same force.

Actually, in the absence of an outside force, both objects would continue on forever. See Newton's first law again.



I agree with you, mass does have an impact on the amount of force required and the distance the object will travel but mass only has a large impact when it is being effected significantly by gravity. Thus the force effecting the objects siginificantly is actually gravity, and the property of the object that is causing it to effected by gravity is its' mass, when the amount of mass is effected by gravity it gives the objects weight.


Almost right. Except that mass has an effect whether you have significant gravity or not. It is actually mass that causes gravity, not the other way around.



Now I admit in our universe there is always gravity acting on objects, this comes from Netwonian Physics every object in the universe will attract every other.

I agree if there is a gravitational field in effect then the objects will not travel the same distance or travel at the same speed however the wieght diffrence of the two objects that we would be talking about would be incredibly miniscule.

If the Earth was placed in the galactic void, not in any orbit, simply "dead in space" its' weight would be incredibly minicule, and the pens' weight would be even less, but the diffrence between the two would be incredibly small, when a large objects' wieght is nearing 0 in whatever unit of measurment you want to use, having zero as the neutral point of the measurmeant system, a significantly smaller item like a pen would have a smaller weight but not a significant weight diffrence. Therfore the pen and the Earth would travel at close speeds, not exactly the same speeds but close.


Not even close I'm afraid. No object in space has any real weight. Weight is only meaningful on the surface of a body like a planet. Also figure, the earth is in orbit which technically means that it's in freefall and thus effectively has no weight. It still has it's 6 sextillion tons of mass, though.



The reason that you can't push a twenty billion pound weight on Earth is because of gravity its' weight is simply to great, but in space that same twenty billion pound weight would be incredibly easy to push if you had something to push against.

However I was not disputing the fact that in an unisolated system two units of matter will not travel at diffrent speeds when fired from the same point with the same amount of force.

Owen Macri

Actually, you could do it on earth too if something were suspending the mass so that it wasn't in contact with the surface. Well, probably not 20 billion lbs but you'd have a hard time with that in space too.

Let me see if I can get it across a different way.

As noted earlier, momentum is defined as mass times velocity. A rocket engine has a finite force that it can apply for a limited period of time. It's not possible to get more than that out of the rocket engine. That force gives you a certain amount of impulse (a change in momentum) that you can apply to an object.

That momentum that you've added to the object from the rocket would be the same, no matter if the object weighs 1 lb or if it weighs 1000 lbs. Let's try this thought experiment. Say that object 1 is made of styrofoam and weighs 1 kilogram. Object 2 is made of lead and weighs 1000 kilograms. Our rocket engine is capable of providing a total change in momentum of 2000 kg m/s (the unit of measurement for momentum. 1 kg m/s is energy of 1 kg moving at 1 m/s). We are in outer space in a perfect vacuum with NO external forces acting on us at all. Starting momentum is 0.

Object 1:
p(momentum) = m (mass) * v (velocity)
2000 kg m/s = 1 kg * v
rearranging gives us
v = 2000 kg m/s / 1 kg (note that here the kg on both sides of the / cancel)
v = 2000 m/s

Object 2:
p = m * v
2000 kg m/s = 1000 kg * v
v = 2000 kg m/s / 1000 kg
v = 2 m/s

So, by applying the same momentum to both objects, the heaver object must necessarily move slower.

By the same token, let's take your hypothetical pen.
Your pen weighs, let's say, 10 grams (.01 kg)
The earth weighs 5.98 x 10^24 kg.

Using the same calculations

Pen
2000 kg m/s = 0.01 kg * v
v = 2000 kg m/s / 0.01 kg
v = 200,000 m/s

Earth
2000 = 5,980,000,000,000,000,000,000,000 kg * v
v = 2000 kg m/s / 5,980,000,000,000,000,000,000,000 kg
v = 3.34 10^-22 m/s (0.000,000,000,000,000,000,000,334 m/s)

So with the same force your pen is moving at 200,000 meters per second and the earth (due to it's MUCH higher mass) is now moving at 334 septillionth of a meter per second.

I hope that makes a little more sense for you.

_Owen_
June 8th, 2005, 06:02 PM
I appoligize, I seriously have no idea what I was thinking about when I typed those posts, I understand your point and... I am sorry I really have absolutly no idea what I was thinking about when I was typing those posts. I agree with you and I don't know what made me think otherwise. It is basic physics, I have no idea what I was thinking when I typed those posts. I appoligize...

Owen Macri

Avatar28
June 8th, 2005, 07:22 PM
I appoligize, I seriously have no idea what I was thinking about when I typed those posts, I understand your point and... I am sorry I really have absolutly no idea what I was thinking about when I was typing those posts. I agree with you and I don't know what made me think otherwise. It is basic physics, I have no idea what I was thinking when I typed those posts. I appoligize...

Owen Macri

Hey, it's not a problem. That's what we're here for is to help each other out. We're straight now. And, honestly, it's been 11 years since my high school physics class, so I had to look some of that up myself. I knew basically how it worked, but I had to research the equations and terms.

Sorry the response was so long. I just tried to address everything as it came.

_Owen_
June 8th, 2005, 09:08 PM
I didn't mind the long response it was very interesting to read.

Thank you, but I really don't know what I was thinking when I typed those posts, I went back and read them like they were someone elses' posts and I was naming off the things that were incorrect, I couldn't believe how I could have actually typed those things and not realized. Thank you though.

I haven't taken my high school physics class, mostly because I am not in high school yet. lol.

Anyways just to clear things up. The amount of energy required to proppel two objects of diffrent masses the same distance and speed in an either unisolated or isolated system will differ. The amount of energy required to propel two objects the same distance and speed is directly proportional to the masses of the objects and the intensity of the surrounding factors, gravity, friction, any oposing force, etc.

Can we agree on this?

Owen Macri

Avatar28
June 9th, 2005, 12:49 AM
Sounds close enough for government work I'd say. You seem pretty intelligent for your age. Keep it up, it's a good habit. :-)

_Owen_
June 9th, 2005, 01:15 PM
Thank you very much! I appreciate the compliment, you seem very smart too! lol.

Owen Macri