Interstellar travel; possible or not?

Hello!
My take on interstellar procreation…
There is nothing magical about antimatter- the production techniques need fine tuning, but
do not need impossible technology
Imagine a mission to a nearby sun-like star
say Eta Cassieopiae -
the (antimatter driven) craft uses the nearby red dwarf companion to decellerate as well as magnetic braking -
once there, an extended family of parental Moravec androids give birth to and raise the human babies (raised from frozen zygotes)

**well that was the plan anyway…
the system turned out to be more inhospitable than planned

Hello!
My take on interstellar procreation…
There is nothing magical about antimatter- the production techniques need fine tuning, but
do not need impossible technology
Imagine a mission to a nearby sun-like star
say Eta Cassieopiae -
the (antimatter driven) craft uses the nearby red dwarf companion to decellerate as well as magnetic braking -
once there, an extended family of parental Moravec androids give birth to and raise the human babies (raised from frozen zygotes)

**well that was the plan anyway…
the system turned out to be more inhospitable than planned

excuse me- I’m new here- sorry about the duplicate post

following up to the deceleration point, once you spin around and reverse, seems you create a large forward wake of radioactive gas – not ideal either. wouldn’t ionic fuel still be more efficient per unit mass since directional momentum is more effective?

still think modern/classical is way too risk-prone and requires advanced/lateral alternatives like cdp as before, but thermonuke seems like very dicey way to pulse.

Decelerating is no more dangerous than accelerating. The waste/exhaust from your propulsion moves away at the same speed relative to your ship regardless of which direction it’s pointed at.

Another form of interstellar propulsion that may be useful is the particle beam and plasma sail combo-
a solar system based mass gun fires tiny pellets of mass- typically iron as the spacecraft, which has a wide magnetic field spread out as a sail- this magnetic field contains and controls a plasma bubble-
the mass pellets vapourise in the plasma bubble and transfer their momentum to the sail and to the vessel.
Deceleration can be a problem, unless a mass beam has already been established at the target star- this is imagined to be the case eventually… otherwise we are left with the small friction effect between the stars magnetosphere and the ship magnetic field (and probably a whole bunch of mini fusion bombs-remember- the exhaust flies away from the ship during deceleration - the ship does not fly into it.)
another configuration possible with Beamriders is the so called cycler arrangement…
the beamrider craft do not decelerate, but continue to ride a system of beams in a circle tens of lightyears long- smaller craft are acelerated to rendevous with the cycler craft at the cruising speed, and are dropped off at the target star- using much smaller particle beams to decelerate…

For some reason I really like that Idea, eburacum.

Well, the idea for the Beamriders came from Karl Schroeder
but the concept of mass pellets has many practical uses, in space technology and warfare…

Scott Dickerson wrote:

To which John Harrison replied:

To which Scott Dickerson replied:

To which I now reply:

According to http://www.itsf.org/brochure/ramscoop.html, the spacecraft in Tau Zero is a Bussard ramscoop. These were all the rage for a couple of decades throughout the Science Fiction community, as the design got around the problem of having to carry all your fuel with you. Theoretically, a space ship with a Bussard collector could travel forever without ever needing to refuel.

The problem with this design is the “ram-scoop braking effect”. A giant scoop, and especially a giant scoop with an even gianter magnetic field, would generate oodles of drag as the interstellar mediam slammed into it at relativistic speeds. A quick back-of-the-envelope calculation in an article I read about space-borne “magnetic sails” deduced that a magnetic ram-scoop would generate more drag than its own thrust could overcome!

I guess that would be a problem to a technology that has mastered interstellar travel but has forgotten how to do DNA tests.

In which case a magnetic sail would be most useful in *deceleration, *cutting down on the amount of fuel needed to perform this operation,
and decreasing the amount of fuel required for initial acceleration by a much larger amount.

[quote]
from Tuckerfan

Originally posted by scr4
Don’t we have the technology for long-term storage of sperm and ova? You can carry a fairly large selection of genes that way.

That we do, but still, how many folks are we gonna need? After all, when the ship arrives, you’re not going to want half the population to be infants or sitting around in storage, waiting to be implanted in a womb. So whilst we can carry millions of sperm and egg, we’re still gonna need a certain number of fleshy humans as well.


Originally posted by BioHazard
I don’t think the Initial population really needs to be very big. I would say maybe 10 males and 50 females, from as many different ethnic populations and different parts of the world as possible (the females are more important in this case IMHO). A male is assigned … (etc., directed-breeding program)

That’s a lot of “control” over an initmate part of people’s lives. I can’t really see folks agreeing to that, or it lasting for very long, …

[quote]

Hmmm…

Let’s assume this SF scenario:

First, of course, that there will be the technological development to build WHATEVER is a generation-ship that can handle multicenturial or multimillennial deep-space manned travel with high reliability and safety.

Assume also that a few hundred more years of development of reproductive technology, lead to the development of (a) foolproof birth-control (b) reliable long-term conservarion of reproductive nuclei © reliable and safe artificial conception and (b) reliable and safe artificial wombs.

Hypothetical assumptions established, then,

Then we could build a long-term generation-ship that is really a moving O’Neill colony, with an “initial population” in the low thousands, like the crew of a large naval vessel or the population of a small town – and at least half again and maybe twice as many as absolutely necessary to run the operation, just to be on the safe side. Let the ship have the carrying capacity for a society at least twice as large again as the original crew, to accommodate for fluctuations in population, and more than that in terms of “idle space” to let people have some private time. That’s right, considerations of “tight efficiency” would have to go out the window if you want people to live their whole lives inside the vehicle.

.

Then:
The ship can carry a “stock” of ova/sperm from maybe hundreds of thousands different people of each sex, NOT related to the crew.
During flight, you establish a strict population policy that still allows for natural reproduction and couple-forming but keeps the total birthrate at less than replacement levels…
…and periodically “replenish” the population with children born out of the “gene stock”, shuffling the ova/sperm, by implantation in willing mothers or else by using the auto-wombs and being “fostered” or given in adoption to the extant crew who may want children above the aforementioned limits. The ‘foster children’ would get a confidential consanguinity record in their medical chart to avoid potential incestuous situations when/if they decided to reproduce. That way you keep periodically inserting fresh genes into the mix AND maintain a population appropriate for the carrying out of the mission.

Once you get wherever you want to get, and establish a viable colony, you then keep bringing genetic material out of “stock” to let the population grow to whatever is the carrying capacity of the location.

Yes, it DOES require you to essentially create a society with a distinct set of values; such as use of birth control being the default behavior; acceptance of birth limits; non-stigma to unidentifiable paternity and willingness to accept children “not of your blood”; if there is a difference between the number of “replenishment” births and the number of willing adoptive/surrogate/foster parents, a disposition towards communal raising. That I am also giving us a few hundred years to work on.

I really do recommend small, light payloads for interstellar ships- zygotes and artificial wombs, robots to look after the children, and didactic programmes (if feasible) to give the children a suitable education…
something similar to a self replicating robot would be a great help at the destination star-
fully replicating devices would involve automated mining and refining of metals and volatiles, and using replicating technology,
a suitable habitat could be constructed, as the chance of finding an earth-type planet is probably less than one in a thousand.

It is a shame to insist on high tech solutions,
but using self replicating tech, and as small a payload as possible, might make it possible to deliver a payload at a nearby star.
To move a generation ship would require a small asteroid made entirely of antimatter- unless the journey lasted hundreds of thousands of years.

And by the time interstellar missions are possible, the genome will be no doubt digitised, so that children may be born with randomly shuffled genes with no specific father or mother-

Moores law would suggest that a vast gene pool- perhaps a ‘gene ocean’ could be encoded on a physically small hard drive of some sort.

some people living today might find this odd, but so is travelling to a different star.

Just had a thought! What about animals? Would we, could we take them? Art? Would we allow people to take original works of art by the great masters with them, or would all of those have to remain on Earth? (Knowing that eventually the Earth’s gonna get wiped out by the sun, would we even plan on sending things like the pyramids with future colonists?)

Did you read my post a couple pages back?

The very long one?
Yes.
Very Good.
Probably no point in using the field till you need to decelerate, as it is quite good at creating a drag.
I am of the opinion that antimatter really will be necessary to make interstellar flight feasible, and the vast amounts of energy available near the sun will be able to power even the most inefficient methods of manufacturing the same.
The postulated Antimatter Farm is not very efficient, but if built in near solar orbit, it will not need to be.

My idea may cause drag, but it will also protect the Ship from erosion from the hydrogen. Plus if the particle accelerator is efficient enough, the drag should be negligable.

Antimatter Fusion hybridships are also quite possible, and can’t really be classed as star trek science-
warps and wormholes are fine for fictional purposes, but need a lot of handwavium…

Ok, no doubt the first few ships that we build will no doubt be similar in many respects to the ones you describe-
an ice shield is also advisable as pointed out in this thread, to intercept any dust particles that get through
one way or another we will get there…