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Planets at near stars?

Posted by: JonHogan - Sat Nov 02, 2013 12:23 am
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Planets at near stars? 
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Post Re: Planets at near stars?   Posted on: Mon Nov 25, 2013 2:27 am
Trade you for my transmogrifier.


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Post Re: Planets at near stars?   Posted on: Sun Dec 01, 2013 3:04 pm
James, I'd have to agree with Jay here, he's given quite enough details for you to be a bit more specific than "you're wrong", and the snide remarks aren't helping either. If he's wrong, how about you tell us how it could be done instead, or at least why he's wrong?

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Post Re: Planets at near stars?   Posted on: Mon Dec 02, 2013 1:44 pm
Beyond the fact that I don't have the time to document gratis, and I doubt he can pay me, the flaws in his description...

...is because it doesn't matter. Such an instrument won't be built in anyone here's lifetime. By the time it is, such things as self-replicating machines will be mature technologies (which is what I was alluding to by mentioning them originally).


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Post Re: Planets at near stars?   Posted on: Mon Dec 02, 2013 10:35 pm
I dunno about that. If the price to orbit drops radically enough, with Spacex's reusability scheme, . . .

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Post Re: Planets at near stars?   Posted on: Tue Dec 03, 2013 2:57 am
The question is not whether a lunar optical array will be built, but whether the telescope could be built with current technology.

The idea of self-replication technology is certainly being investigated with great interest, but where is the profit in growing your own? This single technology would put all manufacturers out of business. If self-replicating products threaten to allow consumers to intercept profits needed by manufacturers to survive, what manufacturer would want to see that technology advance to practicality any time soon?

If we only need to buy “Santa Claus” machines to give us anything we want, why would anyone buy anything else? Better yet, have your friend’s machine make one for you and put the machine’s manufacturer out of business too. Artificial self-replication of sophisticated ultra-precise multi-element electronic, mechanical, chemical, optical, propulsive, hydraulic and pneumatic systems is nowhere close to becoming a practical technology nor likely to be developed by the corporate interests that either fund or manage most technological research. “Santa Claus” machines producing whatever you might desire make for entertaining science fiction, but reality is less obliging.

On the other hand, practical, compact, safe, lightweight nuclear power looks inevitable at this point. So-called “Focus Fusion” reactors and other similar “plasmoid” nuclear reactors are achieving previously unimaginable results right now. Reliable nuclear-powered “bus service” between Earth and the moon would reduce the cost of a lunar optical array to that of major robotic space explorations of the past. Even the very expensive Viking mission to Mars cost “only” a billion dollars.

No one said it would be cheap. The question has only been whether a lunar optical array capable of resolving surface details on planets orbiting distant stars could be built and operated with proven practical existing technology. The answer is yes. Will the cost of deployment continue to trend downward? SuperShuki has it right. Yes.

The Hubble Space Telescope was designed exclusively for deep space observations, but proved to be invaluable when comet Shoemaker-Levy 9 (D/1993 F2) had that little fender bender with Jupiter in 1994. Some of the impact eruptions were as big as the entire Earth. Keeping track of all the planet killers that might wander in our direction suddenly became a very popular idea.

A lunar optical array would be equally adaptable to observations of objects orbiting our own star. Tracking dangerous asteroids and comets with very high apparent magnitude (low brightness) would be child’s play for a telescope with a light gathering capacity hundreds or even thousands of times greater than that of the Hubble. The sooner, the better, I say.

In terms of cost effectiveness, a lunar observatory would be useful for much more than just imaging planets around other stars. Objects in our own neighborhood could also be examined with unprecedented clarity. Thousands of asteroids, comets, Kuiper Belt Objects and more could be as sharply photographed as our own moon. A single enormous telescope could gather as much data as thousands of fly-by space probes at a fraction of the price.

The suggestion from the beginning has been that the technology exists here and now to build and operate, at reasonable cost, all the components of an immense optical telescope on the moon. Meanwhile, current real progress in nuclear technology promises to solve the “shipping” problem.

So it’s a race. Maybe the technology to “grow” a telescope on the moon will arrive first. Maybe space transportation costs will drop so steeply and so soon that the components can be more readily mass-produced here and “shipped” there. My money is on the rockets.


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Post Re: Planets at near stars?   Posted on: Tue Dec 03, 2013 5:12 am
Actually the intent of this thread was the prospect of shooting ity-bity starships at stars in hopes of capturing spy-shots of any planets around them. And it's pretty much gone off the rails from there.

SuperShuki wrote:
I dunno about that. If the price to orbit drops radically enough, with Spacex's reusability scheme, . . .


Not at the scales required to make it worth the effort.


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Post Re: Planets at near stars?   Posted on: Tue Dec 03, 2013 8:02 am
USJay wrote:
Will the cost of deployment continue to trend downward? SuperShuki has it right. Yes.



Of course I am. I'm always right. :lol:

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Post Re: Planets at near stars?   Posted on: Fri Dec 06, 2013 4:34 am
When Jon Hogan started this thread, his “intent” appears to have been to open a discussion considering practical means for making high-resolution observations of extrasolar planets.

Borrowing from the initial post, his question can be summarized as, “Why can we not use an existing tech...to see a nice photo of a planet orbiting a distant star[?]”

Jon’s proposed “solution to finding and verifying planets orbiting stars” was a truly unworkable scheme for a gigantic and immensely powerful space-based “rail gun” (even though his description sounds more like a coilgun) launching tiny space probes with unbelievable accuracy toward distant planets and then waiting around for 40 or 50 years for data to be returned after the probes somehow decelerate into stable orbits instead of zipping past their targets at significant fractions of the speed of light.

James, you rightly dismissed the idea immediately as much too problematic and then you introduced the counter proposal for “a really REALLY big telescope instead.” If the “intent” of this thread were only to consider the practicality of Jon’s “rail gun” idea, that would pretty much have been the end of the discussion. Jon, however, was clearly interested in a serious conversation about how “existing tech” might accomplish his goal and welcomed “any comments” to that end. The train of thought that has followed your counter proposal is still firmly on the rails of Jon’s intent to imagine a technology that could provide that “nice photo” of an extrasolar planet.

It was your assessment that “it would be much cheaper and quicker to just build a really REALLY big telescope instead.” Continuing along your line of thinking, the concept of a Hubble-type telescope stationed at the Earth-Luna L2 point coupled with the immense light-gathering capacity of a very large surface-based lunar optical array has been offered as a more practical means than Jon’s “rail gun” to satisfy his wish. The implication of “practical” is that the concept must also be satisfying to taxpayers who have every right to expect such a project should prove to be public money well spent. Nice photos are not enough. Any publicly owned and operated astronomical observatory must be a cost-effective “working” institution serving the public interest. Any honest contemplation of such an observatory must address the same concerns.

The only disagreement with the concept at this point appears to be how the instrument might be built. You are clearly convinced that yet-to-be-invented technology would be necessary to make the idea practical. I have imagined how “existing tech” might be used to build a practical lunar optical telescope in our lifetime. A meaningful contradiction of the feasibility of the idea has yet to be put forward.


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Post Re: Planets at near stars?   Posted on: Fri Dec 06, 2013 12:29 pm
Sorry guys, i havent read every post. Wouldnt a telescope only give us a picture of a planet hundreds of thousands if not millions of years ago?

Rob

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Post Re: Planets at near stars?   Posted on: Fri Dec 06, 2013 1:24 pm
Well yeah, no matter where you actually take the image, up close or remotely, information only travels at c.

@ USJay- With our current technology it takes decades and billions of dollars to put relatively simple space telescopes into operation. Your idea is completely impractical and logistically impossible in the short term (our life-times) given the existing fiscal and political environment.

Sorry, but that is reality. If you want to play the "what-if" game, you might as well throw in anti-gravity,self-replicating machines, and other hypothetical sci-fiy concepts.


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Post Re: Planets at near stars?   Posted on: Fri Dec 06, 2013 11:47 pm
Rob, if the planet is only fifty or a hundred light-years away then the “picture of a planet” is only fifty or a hundred years old. The nearest confirmed extrasolar planet is less than eleven light-years away. Other candidates, as yet unconfirmed, are even closer.

James, I am pleased to see you finally acknowledging self-replicating machines as science-fiction. As for the time and cost of development, NASA’s “Great Observatories” program gave us our most sophisticated space-based telescopes.


Hubble Space Telescope:

Design proposal: 1968

Launch-ready: October 1986 (18 years after proposal)

The launch was postponed after the destruction of the space shuttle Challenger.

Actual launch: April 29, 1990 (22 years after proposal)

Cost at launch: $1.5 billion (~ $3.1 billion today)


Compton Gamma Ray Observatory:

Design proposal: 1977

Launch: April 5, 1991 (14 years after proposal)

Cost at launch: $617 million (~ $1 billion today)


Chandra X-Ray Observatory:

Design proposal: 1976

Launch: July 23, 1999 (23 years after proposal)

Cost at launch: $1.65 billion (~ $2.24 billion today)


Spitzer Space Telescope:

Design proposal: 1983

Launch: August 25, 2003 (20 years after proposal)

Cost at launch: $800 million (~ $992 million today)


I’m not sure which of these observatories you would consider to be a “relatively simple” space telescope. Please note that costs tend to fall as we gain experience building these things, the development of Chandra’s extraordinary x-ray “lens” being a unique aberration. The L2 component of a lunar optical telescope would be no more sophisticated than the “old-fashioned” Hubble. The tracking mirrors and landers would be small, identical, mass-produced and mass-delivered. Advanced transportation systems are already reducing spaceflight expenses and will only continue to drive down the cost of deployment. “Sorry, but that is reality.”

You are correct of course, a twenty or twenty-five year development period is “decades” and a $3 billion budget is “billions of dollars.” So what? That’s what this kind of exploration takes. The “fiscal and political environment” argument has been used against the development of every one of these observatories. Anywhere between one and ten billion dollars and twenty or twenty-five years from proposal to deployment is affordable and doable. I don’t know about your lifetime, but I expect to stick around much longer than twenty-five years.

Even the over-budget, very poorly managed, much delayed and much more technically demanding James Webb Space Telescope is proving to be feasible:

Design proposal, 1996

Launch (projected), 2018 (22 years after proposal)

Cost at launch, capped at $8 billion


With eight billion dollars we would be able to send thousands of mass-produced mass-deployed mirrors to the far side of the moon.


Last edited by USJay on Sat Dec 07, 2013 10:20 pm, edited 1 time in total.



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Post Re: Planets at near stars?   Posted on: Sat Dec 07, 2013 3:58 am
If you say so Senior Quixote.


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Post Re: Planets at near stars?   Posted on: Sat Dec 07, 2013 1:00 pm
JamesG wrote:
@ USJay- With our current technology it takes decades and billions of dollars to put relatively simple space telescopes into operation. Your idea is completely impractical and logistically impossible in the short term (our life-times) given the existing fiscal and political environment.

Sorry, but that is reality. If you want to play the "what-if" game, you might as well throw in anti-gravity,self-replicating machines, and other hypothetical sci-fiy concepts.

I don't agree that fiscal and political issues are in the same category as anti-gravity and other laws-of-physics defying concepts. At least they can be solved in principle, I agree probably not in our lifetimes.

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Post Re: Planets at near stars?   Posted on: Sat Dec 07, 2013 1:54 pm
You have never dealt with the US Congress then.


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Post Re: Planets at near stars?   Posted on: Sat Dec 07, 2013 4:43 pm
That's why private sector space is so exciting!

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