First Ark to Alpha Centauri

Bryan Heit wrote:

For this link, Bull****!!! Maybe only one ! but I got excited.

The concept of humans having gone through a severe bottleneck has been
well reported in both the science literature and in the media. Here's a
BBC article on the subject:
http://news.bbc.co.uk/1/hi/sci/tech/166869.stm

So let me rephrase it. HSS was uniquely susceptable among all the
apes and monkeys and all the species to be affected by a volcanic
eruption. Why?

Pardon but why would anyone assume intelligence causes a unique
susceptibility to the consequences of a volcanic eruption?

This is an example of science writer syndrome.

If there are not equivalent effects is equal species at the same time
give it a rest.

--
Zionism is warmed over Deuteronomy for atheists.
-- The Iron Webmaster, 3305

George,

I like it.
Any trip of thousands of years, with or without humans at the wheel would
be an exceptionally risky business (much chance of failure, little chance of success),
but it an interesting alternative to let the initial work be done by robots.. Including
feeding and educating the first new generation...)

Many problems shipping this out any time soon though :
For starters : Imagine designing any complex electro-mechanical system which still
works after 3500 years. We have no experience with that at all.

On the up-side, the communication would probably be the easiest problem to solve.
There is no need to let robots build an Arecibo-size antenna from asteroid material.
We can simply go optical :

Ship a 5 or 10meter telescope (also handy to have a sharp eye with you on the trip
and to look around once you arrive), with a nanosec TW laser for transmission,
and a ns pulse detector for reception.
That makes an excellent interstellar com-link, and is do-able today.
Bandwidth might also not be too problematic : ns pulses allows for about 1Gbit/sec
up-link (towards the ship). And there is time to do this...

Rob


"George Dishman" wrote in message ...

"Rob Dekker" wrote in message
. com...
Hi George, You wrote one post earlier, which I found quite brilliant and
novel
(never heard this one before) :

Thanks. While I doubt it's original, recent advances
have made it much less fanciful than it would have
seemed a decade ago.

"We have the human genome so put it on a DVD and reconstruct people
at the other end. No, we don't have that technology yet, but we
have 3,500 years to develop it if the probe phones home for the
plans when it arrives, and it's likely we will be able to launch
this century."

Could you elaborate a bit more on this idea, or was it just a wild thought
?

Well the genome part is somewhat far-fetched, though gene
sequencers are available. There's a long way between what
we have and what would be needed but I think sufficient
first steps have been taken to show that it is feasible
in principle if not yet in practice. However, see the end
of this post for a more interesting variant.

I think the challenge is in the machine that we send on our way now :
Since a machine can only operate reliably within the parameters of what it
was
designed to do, this feels like sending a screwdriver attached to a
cell-phone into space
and calling it later with the plans on how it should assemble a space
shuttle...

That's about right, land a Swiss Army knife on an asteroid
and tell it to turn it into the ISS ;-)

What we would need to do is send a probe with instructions
to survey the system when it arrived, look for rocky
asteroids, extract the metal and build an Arecibo-sized
antenna and solar panels to power the transmitter, then do
whatever scientific surveys we can imagine of everything it
finds and send back the results. If it was in the Alpha
Centauri system, ten years later (or maybe a bit more) it
would receive instructions to make whatever we decided was
needed for the system. If there were an habitable planet,
that could include starting artificial gestation of humans,
though I think we'd do a lot more investigating first.

My personal thoughts are a solar sail for propulsion because
it is equally effective for slowing down at the far end
without having any technology there, and is a passive system
that can be easily repaired if damaged. Speeds around 400km/s
should be achievable this century. This is a long page but
the best is near the bottom

http://www.inspacepropulsion.com/tec...s_physics.html

Here's the sort of material we need though we would also
have to make it reflective at high temperatu

http://www.space.com/businesstechnol...il_000302.html

For navigation, use relative timing of pulsars in the same
way that GPS satellites are used for location on Earth.

For a power, use a radioisotope thermophotovoltaic source
because the active component, basically a solar cell, can
be repaired without exposing a robot to the radioactive
source unlike an RTG.

http://powerweb.grc.nasa.gov/pvsee/programs/tpv.html

and half way down this:

http://www.nasa.gov/home/hqnews/2003...news_c03n.html

The isotope is trickier, my knowledge is limited, but Ni59
has a suitable half life and could be coated to minimise
radiation since only an isolated thermal source is needed.

Control would need to be triplicated at least with a group
of small computers running remote control robots to maintain
and replace each other and the robots. Everything would wear
out over these time scales.

For the robots, we would at least need to develop MEMS
technology to the point that it can manufacture copies of
itself. There's loads of stuff on the web:

http://mems.sandia.gov/scripts/index.asp
http://www.memsnet.org/mems/what-is.html

The best though would be if we can develop to atomic-scale
manipulation. This is old:

http://www.almaden.ibm.com/vis/stm/atomo.html

but could be developed to

http://www.imm.org/Parts/Parts2.html

Of course, not everyone agrees

http://www.imm.org/SciAmDebate2/smalley.html

Most of the technology needed is still well in the future,
but it is all available in development already, and for a
simple scientific research probe, I am fairly sure we could
launch by the end of this century.

Of course if you want to go a little more sci-fi, consider
if we could crack the biological problems of cryonics on
a healthy, fit subject:

http://en.wikipedia.org/wiki/Cryonics

Once frozen, take the subject apart, atom by atom, noting
the relative position of each to its neghbours. Send these
'plans' to the distant star system by radio, reassemble
using local raw material and thaw. It sounds great, but
don't calculate the bandwidth needed ;-)

George

"Rob Dekker" wrote in message
. com...
George,

I like it.
Any trip of thousands of years, with or without humans at
the wheel wouldbe an exceptionally risky business (much
chance of failure, little chance of success),but it an
interesting alternative to let the initial work be done by
robots.. Including feeding and educating the first new
generation...)

My feelings exactly. If I was heading out to a
new star system, I would at least want to know
what was there before leaving. Letting the robots
build a space station and then getting humans
there with minimal risk, without the social
problems of generation ships and without the
enormous power drain needed for "life support"
seems to be an approach with a lot going for it.

BTW, I found the link that tells me this isn't
just sci-fi:

http://www.usatoday.com/news/science...ife-usat_x.htm

"Venter notes the synthetic bacteriophage has
5,000 base pairs in its genome. The human
genome has 3 billion, so similar work in human
form probably won't happen in this decade, he
says."

I suspect that thinking in terms of decades is
too optimistic but given a thousand years or
more, it seems inevitable we will achieve it.

Many problems shipping this out any time soon though :
For starters : Imagine designing any complex electro-
mechanical system which still works after 3500 years.
We have no experience with that at all.

We have quite a lot of information on the way
semiconductor devices degrade and probably a few
decades is the limit. The design starts from the
assumption that every aspect will wear out so the
first requirement is that every part can be
re-manufactured in situ. You want multiple systems
for redundancy against random failures anyway so
each unit would monitor those around it and if
some part fails, the first response would be to
make a replacement and then recover the materials
from the failed unit. Extend that to make
replacements on a regular basis so then most parts
are replaced by new before they fail. The energy
taken and mean life then define the power budget.

Another big advantage is that the probe could be
at a few tens of degrees K which greatly reduces
the mechanisms that cause wear-out so devices
could easily last for centuries rather than
decades. A few watts of power would be adequate
during the trip and of course unlimited solar
(stellar) power would be available once it
arrived.

On the up-side, the communication would probably be
the easiest problem to solve. There is no need to let
robots build an Arecibo-size antenna from asteroid
material. We can simply go optical :

Ship a 5 or 10meter telescope (also handy to have a
sharp eye with you on the trip and to look around once
you arrive), with a nanosec TW laser for transmission,
and a ns pulse detector for reception.

Exactly, and a large solar sail (say a few km in
diameter) would also make a great reflector if
the shape could be stabilised.

That makes an excellent interstellar com-link, and is
do-able today.
Bandwidth might also not be too problematic ..

It depends on compression. I worked out the raw
data and using terabit rates, it would take
longer than the age of the universe. However,
when you seen one red blood cell, you seen them
all (at least for a given person) and there are
a limited number of configurations of molecules
and redundancy at every level so there is scope
for massive compression.

: ns pulses allows for about 1Gbit/sec
up-link (towards the ship). And there is time to do this...

That's the key of course, say it takes 1800 years
to get there, we only need to launch 21st century
technology and even if the initial bit rate is in
the kbit/sec range, it wouldn't take long to upload
the 39th century comms protocols once contact is
established. We already know the background noise
levels so it is just an engineering problem.

Once the comms are in place, upload instructions
to make 39th century tools and then you can build
whatever transmitters and receiver have been
developed by then. Most NASA probes have the
ability to update their on-board software, this
just goes on to include the hardware. After that,
it could be used to create 39th century genome
synthesis equipment if the sytem was attractive.
If not, we could instruct it do manufacture and
launch new probes (using 39th century technology
of course) to another set of more distant star
systems. The aim would be to create a network
of short (10 light year) links spreading out
into the galaxy.

The biggest problem would probably be getting
sufficient autonomy in the software to survey the
system and find the raw materials when it first
arrives, but autonomy is a problem that is already
being worked on and one we must solve even for
exploration of our own outer planets.

George

George Dishman wrote:
"Rob Dekker" wrote in message


BTW, I found the link that tells me this isn't
just sci-fi:

http://www.usatoday.com/news/science...ife-usat_x.htm

"Venter notes the synthetic bacteriophage has
5,000 base pairs in its genome. The human
genome has 3 billion, so similar work in human
form probably won't happen in this decade, he
says."

So George, how can one be sure this new virus don't go out of control
and start attacking people with a force deadlier than AIDS? Do you
think the risks are worth playin'?

Really interesting Abdul, I can easily see this as a good film.

Thanks,

--
Atropine
EL PASO, TX

"Life is easy with eyes closed"

N = R * f(p) * n(e) * f(l) * f(i) * f(c) * L
They gotta be out there........somewhere)

"AA Institute" wrote in message
om...
Since this has a decent level of "Astro" content... I thought it may
make a slight 'thought' contribution (albeit fictionally) to this
group:-

http://uk.geocities.com/aa_spaceagen...acentauri.html

Enjoy...

Abdul Ahad

In article ,
says...
Since this has a decent level of "Astro" content... I thought it may
make a slight 'thought' contribution (albeit fictionally) to this
group:-

http://uk.geocities.com/aa_spaceagen...acentauri.html

Enjoy...

Abdul Ahad


Sorry, only just seen this as a result of another reply.

It sounds as though it will make a brilliant movie or novel, and one I
would love to go and see. The other story in a smiliarish vein that I
hope gets made one day is 'Encounter with Tiber', by Buzz Aldrin & John
Barnes.

Hey guys,
Here's my new address: Todd Ullum 5963 Whitefield Street
Dearborn Heights, Michigan 48127

The pay here as a diesel mechanic is over $32.00 an hour!!