Probe to A Centauri

(Parallax) wrote in message . com...
Assume for the sake of argument that we discover an earth mass planet
in the A or B Centauri system. Further assume spectroscopic analysis
detects copious water, O2, N2, and methane in its atmosphere. Further
assume that it becomes possible with 2-3X Apollo effort to send a
2000Kg probe at .1 c there.

Now, what do we include on this probe to measure things that we will
not be able to measure from our solar system given 45 yr advances in
technology? In other words, given the very long flight time, some
instruments might be made outmoded by advances in remote sensing
capabilities.

Well, over the next 48 years there will be advances in nano-technology
on the order of;

http://www.technologyreview.com/arti...904.asp?trk=nl

and there will be advances in energy technologies such as

http://www.sff.net/people/Geoffrey.L...upersynch.html

So, you could easily end up with something like Bob Forward's
'Starwisp'

http://science.nasa.gov/newhome/head...p08apr99_1.htm

You could adapt microwave or laser energy beams to track a maser or
laser sail that sends nanotech probes to several nearby stars. These
nanotech probes would send data back directly. They may even be
capable of constructing more complex probes from local resources to
increase the range of data possible to send.

Within the next 45 years our present oil supplies will dwindle to
levels lower than they are today. If we postulate that over the next
45 years we'll tap into the solar energy resource in a big way at
prices that are competitive with fossil fuels, then we're really
saying that beamed energy from space costs around $0.02 per kWh. This
will set the stage for continued economic development.

You'll need about 14 trillion kWh to send 10 tons to 1/3rd light speed
- which means you'll need about $280 billion worth of power at utility
rates.

But this could fit within your guidelines. Imagine a world economy
that grows at 4% per year over a 45 year period. This world will be 6
times richer than the world today, $240 trillion instead of $40
trillion per year. The population will only be 1.4x what it is today,
10 billion instead of 7.25 billion. So, people will be richer, and an
Apollo level program in this global economy (1% of a year's entire
economic output of this future world) would be $2.4 trillion. At
these prices, a 3 or 4 Apollo era effort would buy enough power to
send 20 or 30 probes to a dozen nearby stars. The cost of the probes
and the beaming technology would be paid by the power company if you
bought this much power at these rates.

Sander Vesik wrote:
But these were not deliberate interstellar probes, simply probes
that headed off into interstellar space after the main mission was
accomplished. The problem is that the probe you can make in 5 years
- as opposed to now - would probably catch up the other well before
Neptune's orbit.

That seems to my untrained-in-these-matters-eyes to be rather similar
to saying that one should not by a PC in year N because in year N+M it
will be so much more powerful.

I would think that if one could make a faster probe in M years time,
one might simply send it to a more distant target?

rick jones
--
The computing industry isn't as much a game of "Follow The Leader" as
it is one of "Ring Around the Rosy" or perhaps "Duck Duck Goose."
- Rick Jones
these opinions are mine, all mine; HP might not want them anyway...
feel free to post, OR email to raj in cup.hp.com but NOT BOTH...

Ian Stirling wrote:
David Cortesi wrote:

In article .net,
"Carey Sublette" wrote:

...an interstellar probe is...performing a very high speed fly-by...
A unique observation mode that only a probe could carry out is having a
chunk of probe hit the planet's atmosphere and collect data...

This seems a very careless and possibly disastrous plan.
What would be the ground effect of an object moving at
an appreciable fraction of C, grazing the atmosphere of Earth?

Oooh, a meteor!
As long as it's small, there isn't much problem.

Only if "small" means "under a gram".
At "an appreciable fraction of C", the
kinetic energy of the probe would be equivalent to
a noticeable fraction of its rest mass energy.
Even at .1c, this is about 1/2 of one percent
rest mass equivalent. At this speed, a 1 kg probe
would have the energy equivalent of some tens
of kilotons of TNT...

Russell

I never saw an answer to my own question regarding this thread. Re, which makes
most sense, a high-speed flybay/thru probe mission that may take only a decade
or so to get to Alpha cent, thus maybe be in better shape age wise, but only be
in range to take data once there for a couple hours at most?

Or a slower probe that can go into a solar orbit in the AC system and take
long duration measurements and observations, but take most of a generation just
to get there and decellerate, risking the instrumentation being worn out by the
trip before arrival?

Based on a laser-pumped 2-stage solar sail system with micro-miniaturized
nanotech based payload integral tot he ship, kind of like starwisp.

Rick Jones wrote:
Sander Vesik wrote:
But these were not deliberate interstellar probes, simply probes
that headed off into interstellar space after the main mission was
accomplished. The problem is that the probe you can make in 5 years
- as opposed to now - would probably catch up the other well before
Neptune's orbit.

That seems to my untrained-in-these-matters-eyes to be rather similar
to saying that one should not by a PC in year N because in year N+M it
will be so much more powerful.

Not really.
If the task you want the computer to perform will take 15 years with
the PC of today, and 7 years with next years model, then it's a
no-brainer.

I would think that if one could make a faster probe in M years time,
one might simply send it to a more distant target?

Russell Crook - Computer Systems - System Engineer wrote:
Ian Stirling wrote:
David Cortesi wrote:

In article .net,
"Carey Sublette" wrote:

...an interstellar probe is...performing a very high speed fly-by...
A unique observation mode that only a probe could carry out is having a
chunk of probe hit the planet's atmosphere and collect data...

This seems a very careless and possibly disastrous plan.
What would be the ground effect of an object moving at
an appreciable fraction of C, grazing the atmosphere of Earth?

Oooh, a meteor!
As long as it's small, there isn't much problem.

Only if "small" means "under a gram".
At "an appreciable fraction of C", the

I was assuming that 'collect data' meant collect the spectrographic
data from the disintegration of tiny motes.