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Proxima Centauri

Flyaway

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ESPRESSO's observation period was insufficient to confirm or refute the proposed outer planet Proxima c. However, the team found a potential signal that could be from a third planet with an orbit of just 5 days and a mass similar to Mars. If it exists this world would be far too hot for life, but is causing excitement of its own. There is a greater chance a planet in such a tight orbit will transit in front of Proxima Centauri, which would enormously increase our opportunities to study it.

”Is there an atmosphere that protects the planet from these deadly rays?" says Christophe Lovis, a researcher in UNIGE's Astronomy Department and responsible for ESPRESSO's scientific performance and data processing. "And if this atmosphere exists, does it contain the chemical elements that promote the development of life (oxygen, for example)? How long have these favourable conditions existed? We're going to tackle all these questions, especially with the help of future instruments like the RISTRETTO spectrometer, which we're going to build specially to detect the light emitted by Proxima b, and HIRES, which will be installed on the future ELT 39 m giant telescope that the European Southern Observatory (ESO) is building in Chile."
 
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Dilandu

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Seems that planers are much more characteristic for star systems than their absence.

Now the problem is how to took even a glimpse on them from close distance...
 

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That's one of the most fascinating aspect of having 25 years of exoplanets discovery behind us: the sample is now large and diverse enough to get some valuable statistics out of it.

Verdict: something akin to a) there are 400 billion stars in our galaxy alone b) a big percentage of them (60%, from memory) have planets around result.

Which mean there are, potentially, some trillion planets in our galaxy alone. Plus all the other galaxies...

This completely blew my mind.
 

Michel Van

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and it get better



TESS scans for moment over 200,000 stars in the sky to find more Exoplanets.
That include the nearest stars around our Sun
 

uk 75

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I am torn between admiration for the colossal amount of science at work here and the fact that due to the distances involved we are as likely to meet ET as frog in a pond in Oxford has of meeting frogs in ponds in the various Oxfords around the world or even one in Cambridge.
 

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Ah sure, that's the depressing aspect of that business, for sure. Still if we can ever detect life signatures in the atmosphere of an exoplanet, it will be one heck of a terrific moment. It actually excites me as much as SpaceX Mars plan. Hope to see both in my lifetime.

Note that Orion nuclear pulse is perfectly workable and could reach between 1% and 10% of the speed of light. By this metric, Alpha Centauri is "only (only ??!!!) 40 years away, one way. And since it has exoplanets around it... that's the best we can hope for.
 

Justo Miranda

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Ah sure, that's the depressing aspect of that business, for sure. Still if we can ever detect life signatures in the atmosphere of an exoplanet, it will be one heck of a terrific moment. It actually excites me as much as SpaceX Mars plan. Hope to see both in my lifetime.

Note that Orion nuclear pulse is perfectly workable and could reach between 1% and 10% of the speed of light. By this metric, Alpha Centauri is "only (only ??!!!) 40 years away, one way. And since it has exoplanets around it... that's the best we can hope for.
Only 40 years away?
 

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edwest

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I do hope a space drive is developed. Right now, crossing the ocean is a walk in a park compared to going to Mars. Should people go, yes. My proposal is two of everything. Two landers and two 'spare parts' containers with one set in orbit (with the option to dump some spare parts and have it available as a third return craft). There won't be time to send a rescue ship should things go wrong on the surface.

But the day after the announcement of a space drive, plans can change accordingly. However, it must travel at least eight times the speed of light to be really practical for people.
 

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At least one, and preferably more, cyclers would be very handy as well.
 

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Note that Orion nuclear pulse is perfectly workable and could reach between 1% and 10% of the speed of light.
Sadly... no. Realistic near-term (from the vantage point of 1964) specific impulse for Orion was expected to be around 4,000 seconds. *Really* optimistic thinking for a far-term Orion would be about 12,000 seconds.
Math: assume a delta V of 1% c, or about 2,997,920 m/sec. Assume 12,000 sec Isp. If your ship ends up with a mass of one metric ton, you need to start off with...

m0 = 1000 * Math.exp(2997920 / (9.8 * 12000)) =
117830973530924.19

That's 117,830,973,530.9 metric tons for the initial mass, or 117,830,972,530.9 tons of pulse units strapped to a one-ton spacecraft.

If you want to get to even 1% lightspeed, which would put Alpha Centauri as far away as Ivan the Terrible and Queen Elizabeth I, you need to do *waaaay* better than Orion. Not a measly 12,000 seconds Isp, but something pushing a million. Medusa, with a 400,000 sec Isp, could do it with a mass ratio of 2.147.
 

Richard N

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3D printing is advancing so rapidly that by the time these far out missions occur ships will take part files, printers, and feedstocks instead of spare parts. This will take up much less volume and will allow for making changes to parts or completely new designs from data gleaned about what breaks, wears, or fills a new requirement out in service.
 

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EM charged light sails or similar would be useful for deceleration, and possibly for pre-launch maneuvering. For cutting down the trip time a bit, I was thinking more along the lines of a Bussard ramjet, though under current theories it would have to be a very large size to be effective. Then again a huge ship fits in nicely with a ship having an Orion Drive as it's primary propulsion. There are also some other possibilities that have been looked at, such as inertial damping and mass manipulation, that might be able to get our theoretical ship even closer to the lightspeed limit.
 
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The Artist

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3D printing is advancing so rapidly that by the time these far out missions occur ships will take part files, printers, and feedstocks instead of spare parts. This will take up much less volume and will allow for making changes to parts or completely new designs from data gleaned about what breaks, wears, or fills a new requirement out in service.
And if the 3D printer is the first thing that fails? I feel that there would be some items and parts that are deemed critical enough to have ready-made spares on hand.
 

Richard N

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3D printing is advancing so rapidly that by the time these far out missions occur ships will take part files, printers, and feedstocks instead of spare parts. This will take up much less volume and will allow for making changes to parts or completely new designs from data gleaned about what breaks, wears, or fills a new requirement out in service.
And if the 3D printer is the first thing that fails? I feel that there would be some items and parts that are deemed critical enough to have ready-made spares on hand.
Bring more than one printer. Bring a bunch and know that printers can also print themselves. Having only one printer is building in a single point of failure that could stop the whole show, so a competent engineer or manager would root that possibility out. Multiple printers can simultaneously print all the parts of an assembly instead of lining up a queue of parts to be done one at a time on a single printer.

What happens when you run out of spare parts as you are sailing past the rings of Saturn? Spare parts can only fix what they have been designed to fix. They can't be used for anything else. Until they are needed, they take up a lot of space. How much space could you afford to dedicate to warehousing parts on a vessel where space is at a very expensive premium?

A printer can make a vast variety of useful and necessary things including themselves--self replicating machines. They can make new things as well as replacements. It is likely that mining will be done on asteroids and planets and the harvested materials will become feedstocks for the printers. Not planning to use materials you find where you land would require you to bring enormous volumes of materials that would get you into the vicious cycle of needing a bigger ship to launch with more stuff needing more fuel and on and on.

The picture below is one of the PRUSA Printer Farms. There are 300 PRUSA 3D printers making parts for PRUSA 3D printers.
 

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Dilandu

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I was thinking more along the lines of a Bussard ramjet, though under current theories it would have to be a very large size to be effective.
The pure interstellar ramjet rocket seems unworkable from the modern point of view. The drag from hydrogen collector would overcome the acceleration (i.e. the system could be better used as deceleration system - magnetic parachute, using the star solar wind to decelerate the ship) But ram-augmented rocket - which carry fuel onboard & took only propellant from outside - seems possible.
 

Dilandu

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How much space could you afford to dedicate to warehousing parts on a vessel where space is at a very expensive premium?
The problem is not a space, the problem is mass. Space is cheap; you could have spaceship of any possible volume. The problem is mass, that you need to accelerate.
 

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Note that Orion nuclear pulse is perfectly workable and could reach between 1% and 10% of the speed of light.
Sadly... no. Realistic near-term (from the vantage point of 1964) specific impulse for Orion was expected to be around 4,000 seconds. *Really* optimistic thinking for a far-term Orion would be about 12,000 seconds.
Math: assume a delta V of 1% c, or about 2,997,920 m/sec. Assume 12,000 sec Isp. If your ship ends up with a mass of one metric ton, you need to start off with...

m0 = 1000 * Math.exp(2997920 / (9.8 * 12000)) =
117830973530924.19

That's 117,830,973,530.9 metric tons for the initial mass, or 117,830,972,530.9 tons of pulse units strapped to a one-ton spacecraft.

If you want to get to even 1% lightspeed, which would put Alpha Centauri as far away as Ivan the Terrible and Queen Elizabeth I, you need to do *waaaay* better than Orion. Not a measly 12,000 seconds Isp, but something pushing a million. Medusa, with a 400,000 sec Isp, could do it with a mass ratio of 2.147.
My bad, must have confused with something else.

I think the confusion come from Wikipedia (how surprising !) - which mentions a "momentum limited Orion" (see attached)


So, can than Limited Momentum Orion achieve this performance ?
 

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Orionblamblam

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So, can than Limited Momentum Orion achieve this performance ?
Dyson was talking about a sort of far-future pure fusion system. Probably more akin to Daedalus. Orion used known atom bombs which were pure fission; the bombs had a *lot* of "dead weight" including the casing and electronics and the explosives and just about everything, ending up with a pusher plate made out of tungsten. To get starship performance, you'd need a bomb that was little more than a ball of deuterium that underwent nearly 100% fusion. A hell of a big step.
 

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Lasersail all the way. Maybe MagBeam, if they can scale that up.
Also,

One 7x earth-mass (or so) planet at 1.5AU, baby! A little Neptune(well, half a Neptune) in the deep cold!
 

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I think they might need a bit more than normal reactor shielding..... On account of the whole crew and ship being sucked into the black hole thing. It could get a bit wearing.
 

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So, can than Limited Momentum Orion achieve this performance ?
Dyson was talking about a sort of far-future pure fusion system. Probably more akin to Daedalus. Orion used known atom bombs which were pure fission; the bombs had a *lot* of "dead weight" including the casing and electronics and the explosives and just about everything, ending up with a pusher plate made out of tungsten. To get starship performance, you'd need a bomb that was little more than a ball of deuterium that underwent nearly 100% fusion. A hell of a big step.
Ok I see. Maybe that's the reason why Friedwardt Winterberg keep working on "mini nukes".
 

Michel Van

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Robert L. Forward study that concept
he use clever way to stop at target
total weight 82000 metric tons for Laser sail, payload 3500 metric ton.

now the Light sail need a Laser with power of 1.3 terrawatts generate by 1000 Solarpower Laser in orbit around Mercury
This direct the 1000 laser beams into the "Laser beam combiner and redirector" at Mercury L2 point
Here the laser light is send to 100km ø plastic fresnel lens and focus on Laser Sail.
The lasers need 18 years to accelerate the Light-Sail to 20% speed of light and push it 2 light years away
for next 20 years the Sail approach Proxima Centauri to 0.2 light years
in mean time that plastic fresnel lens is enlarge to 300km ø.
The 1000 km ø light sail separate in 300 km ø core while remaining 1000 km ring sail become mirror for Laser light from Solarsystem
Next two years the core slow down and arrive at Proxima Centauri
After flight time of 40 years...
 
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Justo Miranda

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Robert L. Forward study that concept
he use clever way to stop at target
total weight 82000 metric tons for Laser sail, payload 3500 metric ton.

now the Light sail need a Laser with power of 1.3 terrawatts generate by 1000 Solarpower Laser in orbit around Mercury
This direct the 1000 laser beams into the "Laser beam combiner and redirector" at Mercury L2 point
Here the laser light is send to 100km ø plastic fresnel lens and focus on Laser Sail.
The lasers need 18 years to accelerate the Light-Sail to 20% speed of light and push it 2 light years away
for next 20 years the Sail approach Proxima Centauri to 0.2 light years
in mean time that plastic fresnel lens is enlarge to 300km ø.
The 1000 km ø light sail separate in 300 km ø core while remaining 1000 km ring sail become mirror for Laser light from Solarsystem
Next two years the core slow down and arrive at Proxima Centauri
After flight time of 40 years...
Crazy Eddie:D
 

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Flyaway

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chimeric oncogene

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Next two years the core slow down and arrive at Proxima Centauri
After flight time of 40 years...
No, Rocheworld, in orbit around Banard's Star.

A physicist's paradise, with unusual orbital mechanics, large-scale fluid phenomena, and the entire water-gas-ice phase diagram to write endless papers about, populated by a species of surfboarding mathematicians to talk math with.
:p

The sheer wish-fulfillment of the story is so palpable that you can almost see the drool running down the good doctor's face as he fantasized about his scientific wet dream. A lot of fun to read.

Massive scientific hard-ons aside, we must give the good doctor some respect. He did revolutionize the lasersail concept, came up with a lot of cool stuff, and was an excellent science communicator.
 
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edwest

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Chemical and even fusion engines will not solve this problem. Keeping the crew alive and traveling faster than light need to be solved.
 

Dilandu

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Robert L. Forward study that concept
he use clever way to stop at target
Well, for now on I'm pretty willing to agree on the automatic probe that would not deccelerate, making observations from 0,1c run through the system) Even such run would gave enormous amount of data, that would be impossible to obtain from within the Solar System...
 

Dilandu

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Chemical and even fusion engines will not solve this problem. Keeping the crew alive and traveling faster than light need to be solved.
Well, you may drop the "keeping the crew alive", if you aren't talking about ORIGINAL crew. While generation ships tended to be panned by sci-fi writers (seriously, how much novels do you read when generation ship voyage did NOT ended up in total disaster?), they are actually the most theoretically-reliable kind of starship. Due to relatively large human population onboard, generation ship have the best chances to dealt with unforeseen problems that might arise.
 

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You might read Kim Stanley Robinson's Aurora. It describes the voyage of a generation ship and what could happen if the future generations on the ship decide they are not as gung ho as their parents were about being born and having to live off Earth. Their parents got to decide that they wanted to take the risk of leaving home base forever. Their children didn't get that choice and assuming they will adapt to living in a ship in space could be a real deal-breaker.
 
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