Re: starship-design: scoops and sails and something to push against.

[AJ Crowl <ajcrowlx2@ozemail.com.au>]

Hi Group

L. Parker wrote:

> Zenon,
>
> > Statically probably yes.
> > Hence Kevin wrote about pulsing the fields in some way.
> > That might work, like the similar trick with pulsing
> > magnetic fields in electric motors.
>
> I read somewhere once about a stardrive that relied upon pulsed magnetic
> fields created by air-core magnets. The idea was to switch them on and off
> in such a way that the fields were not conserved locally, but were conserved
> globally so there was no violation of physics involved...I also seem to
> remember a column by John Cramer explaining why it wouldn't work.

It did work, except it was just a "photon" rocket. The pulsations produced
microwaves in a beam, thus providing thrust albeit very low thrust.

>
>
> I'm no physicist, but I don't think it will work. This is an excellent
> example of why they want to create or find a magnetic monopole. Steve or
> David can probably give you a better explanation than I can.

If you can make a monopole you have something even better than anti-matter. A
monopole is a one-dimensional space-time flaw and it induces PROTON DECAY. In
otherwords you can hit it with a beam of protons and get a stream of pions
moving at 0.943c coming out the otherside! Almost perfect space-drive, since you
don't need to fiddle with anti-matter! Any old junk will do, but hydrogen is
best.

A related system beams protons at a Q-Ball, which is a quark-aggregate that
might also induce a GUT reaction and cause Proton decay. Either one will do. The
best would be a lens of distorted space-time, rather than the microscopic specks
that monopoles and Q-Balls would manifest as.

>
>
> I'm afraid the best we can hope for in the time frame we are discussing is a
> first or second generation fusion engine or hybrid antimatter/fusion engine.

Unless we can crack GUT physics and induce proton-decay or higher-level GUT
phase-transitions. You're right - that's the best we can currently design, some
sort of fusion drive. I'd like to see a hybrid system, which should get a Ve of
~ +60,000 km/s. That'd be ideal. Using a magnetic-sail to deccelerate it'd be
able to reach ~ 0.5 c with a mass-ratio of ~ 20. We could generate anti-matter
using collectors constructed from a base on Mercury, but in a lower solar orbit
[0.01 - 0.1 AU], somehow stepping-up incident photons into the gamma-ray level,
then inducing pair-creation to get anti-protons.

> In truth, we can design a ship around a drive that can get a small vessel up
> to 0.3 c. It won't be as fancy as Kelly's Explorer, but we should be able to
> put a crew of 5 to 10 people on Alpha Centauri after a 12 year flight. Kind
> of long, but doable. Tau Ceti of course would take longer, probably at least
> thirty years one way. We would have to put a crew of twenty year old
> astronauts aboard and expect them to get back when they were eighty!

Personally I wouldn't want to send anyone until we could put them in stasis.
Just how? Some sort of nano-tech system could wrap them in diamond at a
molecular level, I'd guess, but maybe some sort of cryo-system will be more
likely. Ideas anyone?

> Lee

A more likely star-flight scenario, I think, is fleets of mobile space-colonies.
They'd be co-operatives who'd mine the Jovians via a skyhook system, and they'd
have huge mass-ratios thanks to using no tanks, bar minimal thermal wrapping.
With mass-ratios of 100 they could get up to ~ 0.2c using D/D reactions. Or
maybe a lithium dwarf star will be found close to the Sun and that'd become a
great fuelling post. If you're going to spend decades between the stars why not
go en masse?

Adam