h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Would/could that generator be the engines? And does it ALWAYS use more engery than it outputs?

because anti-matter as a power source works by total conversion of matter back into energy, and the anti-matter has to have the energy put in to create it, then it is always inefficient.

As regards the generator being the engines, If you are carrying the power to generate the anti-matter, most of the time it is more efficient to use it directly.

Anti-matter as an energy source is likely to be used either for it's energy density, so you get a lot of power per weight, of for it's relative cleanliness (low grade radio-activity which disappears in a relatively short time).

Adding a generator to generate the anti-matter would be prejudicial to either of these goals.

Ok then, going back to the hydrogen engines...

Would a fusion engine, though different in its working from a matter/anti-matter engine, be more efficient, but not as clean?

fusion engines have a lot of advantages, but they require a lot of shielding. they also tend to become too radioactive to go into to maintain them after relatively short periods of use. (not high grade radiation, just lots of it).

The other problem with fusion is efficiency. The higher up the scale you can get (nearer to iron), the more efficient, but the more radiation and higher temperatures you need. as you can imagine, this means even better shielding, which as it needs to be concrete, is a bit much for a spacecraft.

but things like laser catalysed lithium deuteride pellets are rather usefull, but it is a bit hard to get the detailed figures about them, as they are classified under the star-wars weapons initiative.

The dictionary says that lithium is used especially in nuclear reactions. Do you know if there is anything called dilithium crystals? (Going back to the whole Star Trek deal) Is there such a thing a dilithim crystals? The main difference here is that they use the crystals in their warp drive. It's basically the intersection point for the matter and anti-matter. Ignore this if it's classified, but what exactly do the pellets do?

lithuim is used in nuclear energy as a cheap way of doing fusion.

in particular, it becomes much cheaper (in terms of energy) to convert your feedstock into Beryllium.

lithium deuteride is basically lithium chemically combined with the form of hydrogen found in heavy water.

When you put this chemical into a laser catalysed fusion reactor, inside very small pellets, you get incredible amounts of pressure from the multiple lasers all being focused on the same point, along with incredible heat.

This makes the fusion much easier.

As a result you get much higher returns of energy out of your generator, but I can't give you detailed figures, due to both the hig energy lasers in general, and their application to laser catylised fusion being military secrets under america's strategic defence initiative (or star wars program).

In a previous message, you basically stated that if you froze anti-hydrogen down to about 3 or 4 degrees kelvin, you could store it in a bottle with needs only a electrostatic field, and not a magnetic one. Could you use an electrostatic field for anti-matter, and which field would be better: magnetic or electrostatic?

I don't actually know if you could use electrostatic for antimater.

as for which would be better, I would prefer electrostatic, but again th information is very hard to find.

We are not exactly talking about how many apples in a bag here. some of this stuff is right on the border of what is publically available.

Do you know where I could go to find out more information about all this? I know that you couldn't possibly tell me everyrthing I want to know, considering half of it would probably be classified, and the the other half would probably be my questions going towards the extreme. I don't want to take up all of your time...

For further information, you probably want to be looking in science books, university websites, etc.

As for taking up too much of my time, if you do, then it will just take me a bit longer to answer.

ask away.

Okie dokie...

Since I've currently run out of questions on the current subject, I'm going to move on to space in general...do you mind?

not at all.

As chairman of boston astronomers (http://www.xyroth-enterprises.co.uk/bostonas.htm) I should know quite a bit about space in general.

your first question please.

The Pluto-Kuiper Belt Mission is planning to start in 2006 and finally reach Pluto/Cheron as early as 2015. I read that the spacecraft will pass by Jupiter to use the planet's gravity to help slingshot it the rest of the way. Just what kind of spacecraft are they using? I can't find any reference to it on the site I was on.

P.S: Nice site

It appears to be a nuclear powered spacecraft, using existing technology to give low power consumption.

They appear to have learned the lessons from their development of the beowulf computing technology (documented on my site) and from the "cheap probe" program that included the mars pathfinder mission.

By using commodity off the shelf components (refered to as cots for short) they manage to keep the cost down, and the reliability up.

having said that, there is currently no provision for it in the 2002 budget, so if america's conress wimp out, it might not happen.

PS you say nice site. are you refering to the boston astronomers site, or the bigger xyroth enterprises site which includes it?

About this nuclear power...would there be a slight radioactive trail behind the craft as it moves, or not? I don't know that much about nuclear power....

And for the site, I think both parts are nice.

generally, nuclear power in current spacecraft are a small piece of radioactive material being used to generate heat. thi is then harnessed by using the seebeck effect (explained on my site at http://www.xyroth-enterprises.co.uk/seebeck.htm) to generate an electric current, which then is used to power some form of reaction drive.

There would not be any radiation trail, but because they all use reaction drives, there would be some sort of particle trail which would theoretically be detectable, but in practice would be to minute to detect.

Which power system would be better for longer trips, such as...a trip from Earth to Jupiter? Nuclear power, or laser catalysed fusion power? The nuclear power has been made to have a low power consumption, but what are the advantages of laser catalysed fusion?

both are nuclear power, but conventional nuclear power for spacecraft is fission.

The advantages of fission are energy density (they can run for years producing usefull amounts of energy) for example voyager 1 was launched in 1977 and is estimated to still have energy to last another 20 years (if the rest of the equipment is as reliable).

laser catalysed fusion is definately experimental at the moment, so most of it's benefits are predicted rather than actual until reactor sizes come down. then it is a question of engineering.

How about plasma energy?

If you can generate enough plasma at required temperatures, and guide the flow by a magnetic field (which would also heat the plasma), would there be enough force to propel the rocket forward for extended amounts of time?

Plasma energy?

plasma is a high energy state of matter where the electrons have been stripped off.

examples include the northern and southern lights.

I suspect what you are actually talking about is ion drive (as seen in the probe "deep space 1".

this works by emiting charged particles out of the back of an engine in much the same way that electrons are emited from the guns in the back of a tv tube.

Ion drive is very effective for interplanetary and interstellar flight, because it usesminute accellerations for a long time.

for the same reason,it is useless for atmospheric use, as it doen't have a large enough kick to overcome the friction and gravity.

Or you might be talking about a bussard ramjet, where you use massive electromagnetic fields (bussard collectors) to channel the charged particles that are available in space, compresses the particle stream, and push it out the back of the engine.

these are usefull for interstellar flight, where you are going fast enough to replace the paricles you throw out the back of your engine, but for interplanetary use, you are just not travelling fast enough.

(by the way, the bussard collectors can be used to catch the same particles to feed to your fusion reactor).