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A Real Sun Probe, Take the Solar Plunge
Guest_Richard Trigaux_*
post Dec 26 2005, 08:52 PM
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QUOTE (ljk4-1 @ Dec 26 2005, 06:03 PM)
Maybe if we tell Bush there's a lot of oil on the Sun....
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Yes, there is plenty, it is called solar energy.
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antoniseb
post Dec 27 2005, 01:50 AM
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It would be possible to create a probe that could reach the photosphere, and continue into the body of the Sun a short way. There is a lot of question as to how it might communicate out of the Sun. Communication might be possible with x-ray lasers. Anything with a lower photon energy might get absorbed pretty quickly by the plasma.

This is not a realistic plan for the short term future, but you can imagine a craft that has a mass of billions of tons, and has a mechanism for spraying an opaque cloud out in front of it to shield the vessel with disposable shielding. Alternatively, or in addition, you might have a conveyer belt of rigid shielding that only exposes the individual tiles to the Sun for a small fraction of the time. Excess heat is blown off in the opaque jets previously described, or used to heat gases to thrust out the back.

The Photosphere's density is very low. It would take quite a while for a billion ton object to be vaporized if it was well designed. Just as a wild guess, such a craft could potentially descend a thousand miles.
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dvandorn
post Dec 27 2005, 06:25 AM
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QUOTE (Richard Trigaux @ Dec 26 2005, 02:52 PM)
Yes, there is plenty (of oil on the sun - Ed.), it is called solar energy.
*

Absolutely. After all, fossil fuels are nothing more than storage units for solar energy.

-the other Doug


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“The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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Guest_BruceMoomaw_*
post Dec 27 2005, 08:36 AM
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The trouble is that we haven't as yet come up with a way to collect and store it that's even remotely as efficient as utilizing -- at breakneck pace -- the fossil fuels that Mother Nature thoughtfully spent hundreds of millions of years accumulating for us. Talk about spendthrift heirs!

As for solar astronomy missions -- including Solar Probe -- they may have genuine practical importance. We need to know more about the Sun's longer-term activity cycles, in order to judge what effects those will have on Earth's climate that will be overlaid on top of the effects from the buildup of man-made greenhouse gases.

And, yep, the idea of Solar Probe has been around for a long, long time. Back in the early 1980s it was a big hulking thing called Starprobe that weighed thousands of kg and would have had to be launched by a Titan. Then, in the early 1990s, someone developed a way of greatly shrinking it by shaping the heat shield in such a way that it doubled as the probe's high-gain antenna. Still later, however, it became clear that electronic miniaturization has advanced to the point that we don't need that peculiar idea to build a lightweight version of Solar Probe. As with ion drives, We Have The Technology, and the only thing stopping us from doing it is the cost.

And Congress itself has repeatedly expressed some interest in this mission, and at least twice has inserted an additional $10 million into NASA's budget -- which NASA hadn't asked for -- for design studies. At some point, it WILL fly. (The analogy that comes to mind is SIRTF, which got delayed repeatedly, but in the process underwent technological evolution that both drastically reduced its cost AND increased its science output. And finally, it did fly, as the extremely successful Spitzer Space Telescope.)

One of the more mind-boggling things about this mission, by the way, is that one of its goals is to take images of the solar corona -- from inside the corona, looking out.
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BlackMage
post Dec 28 2005, 07:26 AM
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Well, if one gets to think into the really long-range future (think decades), then a Solar Sample Return mission from the corona (or even the photosphere, if you want to get REALLY fanciful) might finally find a use for Bussard's beautiful yet cosmically inefficient ramjet.

Use electromagnetic fields to collect hydrogen from the corona to fuel a fusion rocket, in order to collect samples and fly back to Earth. It'd be a project of stunning magnitude-thousands of tonnes, probably-but what's a few billion to a thought experiment?
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tty
post Dec 28 2005, 11:53 AM
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QUOTE (dvandorn @ Dec 27 2005, 08:25 AM)
Absolutely.  After all, fossil fuels are nothing more than storage units for solar energy.

-the other Doug
*


So is uranium, though from an earlier stellar generation.

tty
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Bob Shaw
post Dec 28 2005, 12:05 PM
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(Sigh)

You're all missing the obvious way to design a Solar Probe, although ISA already described a most persuasive mission scenario.

Just build one and launch it at night!

(Ducks and runs!)

Bob Shaw


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Remember: Time Flies like the wind - but Fruit Flies like bananas!
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Bob Shaw
post Dec 28 2005, 12:08 PM
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QUOTE (Bob Shaw @ Dec 28 2005, 01:05 PM)
(Sigh)

You're all missing the obvious way to design a Solar Probe, although ISA already described a most persuasive mission scenario.

Just build one and launch it at night!

(Ducks and runs!)

Bob Shaw
*


Sorry, I forgot - ISA is the Irish Space Agency. Actually, they were going to send three spacecraft originally, with two levels of redundancy. To be sure, to be sure!

(Ducks, runs, and hides up a tree)

Bob Shaw


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Remember: Time Flies like the wind - but Fruit Flies like bananas!
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edstrick
post Dec 28 2005, 12:30 PM
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A limitless, though relatively small, source of energy is the mouth-flapping of "zero-point energy" and the like folks. Considerably more abundant is the hot-air from politicians and we-know-what's-best-for-you advocates.
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kwan3217
post Dec 29 2005, 05:05 AM
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I recall a sci fi story from long ago about a manned station and manned boats on the surface of the sun. The three main obstacles to operating on the surface of the sun are:

1) intense heat
2) no solid surface
3) 32G surface gravity

The solutions are as follows

1) Carry a large supply of carbon, and pump it out of the surface of your platform. The carbon vaporizes and carries off the heat. Use carbon since it has the highest known melting and vaporization temperature of any substance. It acts like an ablative heat shield, or as the story described it, the bottom layer of a water drop in a hot pan.
2) Carry a big particle accelerator torus, and put a bunch of plasma in it and run it around the right direction such that it generates a magnetic field counter to the sun's magnetic field. If it is strong enough and controlled well enough, it will support the platform
3) Put this torus on the roof of the platform. Run the torus fast enough that through special relativity it gains enough mass to generate a 31G field in the up direction.

In the story, the mission of the platform and boats was to induce precisely controlled solar flares which would impact the atmosphere of the Earth, and in this manner they could control the weather. There was a vast representative democracy back on Earth, the Weather Congress, to decide what weather to have. There was a vast scientific institue, the Weather Advisors, to figure out how to implement the decisions of the Weather Congress. And there was the Weather Service, manning the base and boats on the sun, to carry out the plans of the Weather Advisors.

Now I know that there are dozens of reasons why the solutions proposed could not work (Where does all the carbon come from? What is the power source? What about tides from the gravity generator? Can you really use a plasma torus like that? The photosphere is hundreds of miles thick. Solar flares can't really influence Earth's weather that much. Even an enormous nuke is a mere sparkler on the sun, flares can't be induced.) but it is still interesting that someone actually considered a solution for landing on the sun which doesn't involve landing at night.
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Guest_Richard Trigaux_*
post Dec 29 2005, 08:20 AM
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QUOTE (edstrick @ Dec 28 2005, 12:30 PM)
Considerably more abundant is the hot-air from politicians and we-know-what's-best-for-you advocates.
*


perhaps it is this which creates climate change. We could eventually find a linear relationship between the temperature increase and the number of forgotten promises by politicians.
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Guest_BruceMoomaw_*
post Dec 29 2005, 11:37 AM
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That story was Theodore Taylor's "The Weather Man". Interesting idea, but even at age 12 it struck me as being a wee bit implausible. (He later wrote a sequel involving a suicidal trip to the CENTER of the Sun to stop an instability therein.)
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Guest_Richard Trigaux_*
post Dec 29 2005, 02:56 PM
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PINK FLOYD


SET THE CONTROL FOR THE HEART OF THE SUN
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Guest_BruceMoomaw_*
post Dec 29 2005, 04:38 PM
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So THAT'S how they got so pink.

By the way, Solar Probe originally started out as one of that very unlikely trinity of missions that were set up under Goldin's tenure to supposedly develop the new technologies necessary to go to "the most difficult destinations in the Solar System" -- along with Europa Orbiter and the Pluto flyby. This program was commonly called "Fire & Ice", but had the awkward official name of "Outer Planets/Solar Probe". (Back in 1999 I wrote to Chris Chyba suggesting that it needed a better name, and proposing -- roll of drums -- "New Frontier". He was noncommittal. Alan Stern later told me that he'd considered that name for New Horizons, but decided that the JFK reference might make Bush even more hostile to the probe than he then was -- only to have O'Keefe later give that name to the entire middle-price planetary-probe program.)

Anyway, the idea -- which in retrospect seems utterly cockamamie -- was to connect these three utterly different missions by using the same "core spacecraft" for each of them. Goldin then decided to make things even worse by overriding the recommendation of COMPLEX that the Pluto probe -- which, unlike the other two, actually required NO new technology -- fly first in 2003; he ordered instead that Europa Orbiter be flown before the Pluto mission. The result, naturally, was to delay the Pluto mission further and further as the impracticality of doing Europa Orbiter any time in the near future became obvious -- but I was told at the October 2000 meeting of the Solar System Exploration Subcommittee that Goldin told an aide that he had actually done this (along with insisting on totally impractical super-miniaturization of the Pluto probe) as a subterfuge for getting rid of the Pluto mission altogether, on the grounds that "Nobody gives a damn about Pluto."

This is where, to my lasting amazement, I enter the story. I did an August 2000 piece for "SpaceDaily" proposing that not only did the Pluto mission not require any new technologies at all (unlike the other parts of OP/SP), but that it could be flown much more cheaply by simply mildly modifying the design of either of the two existing Discovery comet probes, Stardust and CONTOUR. A month later, NASA surprised everyone by suddenly putting out an AO for ideas for a cheap Pluto probe design -- which they made very clear they were doing extremely grudgingly, and with no desire to really fly the thing.

When I got to the SSES meeting in October, there were stacks of my article on the information table; and on the first day two guys from Lockheed Martin got up and presented the company's proposal for modifying "Stardust" for the Pluto mission -- which reflected my own suggestions down to the very last goddamn detail, except that the launch would not be possible before December 2004 and so required a bigger booster than my suggested November 2003 launch. They told me later that Lockmart had come up with the idea completely independently, which I believe -- it had not exactly been a hard idea for me to come up with. But, to my stupefaction, although I had come to that meeting just as a reporter, I discovered that in the process of asking the assembled scientists for information on various subjects I was also GIVING them some information, and so Michael Drake ended up letting me take a bigger role in the debate over Pluto than he was legally supposed to do. While there was universal agreement that the argument for a near-future Pluto/Kuiper flyby was overwhelmingly strong, on the last day there was a debate over whether they might "anger NASA" by recommending it, and I ended up giving them a mini-Agincourt speech to the effect that their official job was simply to recommend the best scientific strategy for flying planetary missions, that the Pluto mission was clearly part of this, and that if NASA turned it down anyway for non-scientific reasons the agency had no reason to blame them for recommending it.

Whether this made a difference or not, they DID very strongly advocate the mission in their report, and the scientific pressure for it simply got stronger and stronger, until we finally had the spectacle -- almost unprecedented at the time -- of the GOP Congress telling not only NASA but the White House itself to go a kite, and ordering inclusion of money for the mission in the NASA budget. (The 2002 Decadal Survey report forcefully recommending it was probably the last impetus necessary for this.)

I'm still trying to determine just how important my role in all this actually was; but it seems certain that Simon Mansfield (the editor of "SpaceDaily) and I had SOME effect. I later learned that NASA was actually shutting up any engineer or scientist from publicly proposing an economically designed Pluto mission by threatening to cut off their grants, and so Simon and I ended up innocently belling the cat by publicly proposing the idea for the very first time and thus making it impossible for NASA to hush up the idea any longer. This may or may not have been what forced it to put out that reluctant AO for ideas on just this subject a month later; but judging from my treatment at that SSES meeting a month after that, my article played at least some contributing role in getting NASA's planned cancellation of any Pluto flyby mission reversed.

New Horizons, of course, IS based on CONTOUR -- although much more loosely than its competitor "POSSI" was based on Stardust -- but I can't believe that I inspired that idea; there were surely engineers already thinking about it. But -- because, by pure dumb chance, Simon and I happened to be in exactly the right place at the right time -- I did play a role in getting it flown. I take for granted that I will never get the chance to do anything remotely as important for the rest of my life. (Not that I've quite given up the hope that someday lightning might strike twice -- although my recent plan to push a penetrator as a small piggyback lander for Europa Orbiter turned out to have a subtle but very important flaw in it pointed out at the recent COMPLEX meeting. Oh, well. Back to the drawing board.)

Anyway, in retrospect it's perfectly obvious that Europa Orbiter was the most complex of the three OP/SP missions and should therefore have been flown last, with the Pluto flyby going first and Solar Probe second. Thanks entirely to Crazy Dan Goldin, this didn't happen -- or we could have seen the Pluto mission launched, with considerably lower cost and more science return, in November 2003 (which would even have allowed it to do a very close Io flyby en route!) And Solar Probe is STILL a very important mission -- in terms of practical human benefit, maybe the most important of the three -- and badly needs to be flown.
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Bob Shaw
post Dec 29 2005, 04:45 PM
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Bruce:

Careful there Ted, or Crazy Dan might try to pull strings to have you nominated as the command pilot of a (briefly) manned Solar mission!

Of course, he'd stand every chance of getting the second seat reservation for himself...

...I wonder who'd get the third slot?

Bob Shaw


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