New Horizons at Pluto

grmcdorman said:
Yeah, I forgot about that uncertainty. There's also the issue that, as Pluto is very small, you're going to exit the atmosphere very quickly on any open (non-orbital) path. Basically, using aerobraking at Pluto is pretty much a non-starter.
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Thanks, and for others replies too. I guess we won't be putting a man on Pluto any time soon then.
 
CelticRose said:
That assumes that it's not some kind of extremophile that actually likes the cold.

I would imagine that any life we may find on other worlds would be very different from life on Earth simply because it would have had a different set of conditions to adapt to. We may find stuff that doesn't need external heat or light to survive. Or not. :)
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Could be a lithophile. However, as close to absolute zero as Pluto gets I can't imagine life at the surface. It is one of the few physical constraints that is actually necessary.
 
BenBurch said:
rjh01 said:
Odd that the diameter and atmosphere is not known. There are plenty of stars in the sky. So wait for one of them to go behind Pluto and time how long the star cannot be seen. Then repeat a few times and the diameter and atmosphere composition and strength would be known.
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Occultations of usable stars are very rare.
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Yes, occultations are rare; but they were able to do that. The issue is not that the size is completely unknown, but that the error in the measurement - i.e. the uncertainty - was sufficiently large to be a problem. New Horizons, in fact, found that Pluto is larger than estimated by a small amount, just over 3%: see https://www.nasa.gov/feature/how-big-is-pluto-new-horizons-settles-decades-long-debate and http://www.space.com/29924-pluto-larger-than-thought-nasa-flyby.html

Apparently Pluto's atmosphere is a problem; an atmosphere leads to a gradual dimming (and bending) of a star's light, unlike an airless body where it will just wink out and back in.

From the latter link:
space.com said:
New Horizons' latest views of Pluto have shown the dwarf planet to be 1,473 miles (2,370 kilometers) across ...
Previous estimates for the size of Pluto had put its radius at 1,430 miles (2,301 km)
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Rincewind said:
Thanks!

Excellent!
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Yes, it's exciting, and I never thought Pluto would be.
From blurry image to close ups of ice mountains. Stunning achievement: when Tombaugh found it we couldn't get off the planet and now we've just sent a probe by.
 
Beelzebuddy said:
Re: smooth surface, my money's on some kind of slow erosion caused by Pluto's atmosphere alternately sublimating when it's close(r) to the sun, and freezing out when it moves farther away. Sublimation should favor sunnier peaks and crater rims, deposition should favor shadowy valleys and crater floors, so the one should (very, very gently) shift mass into the other.
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Interesting. I hadn't thought of that. Does it happen seasonally on Earth on glaciers and the like, or do other effects, such as precipitation, overwhelm it?
 
Monketi Ghost said:
Yes, it's exciting, and I never thought Pluto would be.
From blurry image to close ups of ice mountains. Stunning achievement: when Tombaugh found it we couldn't get off the planet and now we've just sent a probe by.
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My thoughts exactly. What with this and Rosetta/Philae we're on a bit of a roll above the stratosphere. Below not so much, of course, but from the gutter we gaze at the stars.
 
Thing is, the ion engine wasn't on the table as an engineering option when New Horizons was designed, as far as I know. What's more, Dawn has been, in part, a proof-of-concept for the engine; for the NH mission, I don't think that planners would opt for it even now until it has been proven for long duration missions.
 
Actually, proof-of-concept was Deep Space 1, launched in 1998. So yes, it was available when New Horizons was designed.

However, the design to which I linked calls for 4 RTG's -- NASA did not have that much plutonium-238.
 
Ah. I stand (sit) corrected, then.

Mind you, it still would require ~15 years transit (going by the posts here), and be relying on cutting-edge techniques; from what I've read, the NH project was touch and go for a while; adding a new, cutting-edge feature to it might have been enough to push it off the table (even leaving aside the issue of enough RTG fuel).
 
grmcdorman said:
Ah. I stand (sit) corrected, then.

Mind you, it still would require ~15 years transit (going by the posts here), and be relying on cutting-edge techniques; from what I've read, the NH project was touch and go for a while; adding a new, cutting-edge feature to it might have been enough to push it off the table (even leaving aside the issue of enough RTG fuel).
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Perhaps the science findings will provide motivation for such a future mission.
 
Mark6 said:
Actually, proof-of-concept was Deep Space 1, launched in 1998. So yes, it was available when New Horizons was designed.

However, the design to which I linked calls for 4 RTG's -- NASA did not have that much plutonium-238.
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They still don't, the supply is (IIRR) about 16kg, much of which is earmarked for the Mars rover programme.
 
RussDill said:
Perhaps the science findings will provide motivation for such a future mission.
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[Farnsworth]A man can dream, though. A man can dream.[/Farnsworth]

I hope this does generate sufficient interest to get people looking up at space again, and have a certain personal stake in it (my company doesn't do rocket design/testing, but my work with NASA is affected by their budget). That said, I don't think anything short of confirmed alien life wil get folks interested. We haver two cases of potential life (I believe we have found fossil stromatolites on Mars, and we may have found evidence of life on a moon) and people STILL say mathematically illiterate nonsense like "Why don't we use that money to solve problems on Earth first?" New Horizons is a great thing, but I have little hope for it generating sufficient public interest to have an impact on the budget.
 
Dinwar said:
[Farnsworth]A man can dream, though. A man can dream.[/Farnsworth]

I hope this does generate sufficient interest to get people looking up at space again, and have a certain personal stake in it (my company doesn't do rocket design/testing, but my work with NASA is affected by their budget). That said, I don't think anything short of confirmed alien life wil get folks interested. We haver two cases of potential life (I believe we have found fossil stromatolites on Mars, and we may have found evidence of life on a moon) and people STILL say mathematically illiterate nonsense like "Why don't we use that money to solve problems on Earth first?" New Horizons is a great thing, but I have little hope for it generating sufficient public interest to have an impact on the budget.
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I can only second this.
The early pictures of Saturn/Neptune/Uranus are at least part of what got me into science in the first place, even though I chose a different field in the end.
Personally I hope to see a serious expedition to the potential water bearing moons to see if there is an ocean under that ice, and if there is something alive in there.

As for the 'we must solve problems now' crowd. I always counter that most real progress we made came from curiosity rather than problem oriented research. Those that first researched electricity or nuclear physics did not do so to create computers or nuclear power plants.
 
Dinwar said:
[Farnsworth]A man can dream, though. A man can dream.[/Farnsworth]

I hope this does generate sufficient interest to get people looking up at space again, and have a certain personal stake in it (my company doesn't do rocket design/testing, but my work with NASA is affected by their budget). That said, I don't think anything short of confirmed alien life wil get folks interested. We haver two cases of potential life (I believe we have found fossil stromatolites on Mars, and we may have found evidence of life on a moon) and people STILL say mathematically illiterate nonsense like "Why don't we use that money to solve problems on Earth first?" New Horizons is a great thing, but I have little hope for it generating sufficient public interest to have an impact on the budget.
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Yeah, don't hold your breath. :(
 
Dinwar said:
New Horizons is a great thing, but I have little hope for it generating sufficient public interest to have an impact on the budget.
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A wonderful thing indeed but there's an unfortunate air of completion about it. It doesn't open on to anything, unlike, say Hubble or the Mars Rovers, or Rosetta - manoeuvring about amongst bolides is surely going to be a thing of the future.

Pluto : tick. Won't go back. (If we do go out there again we'll surely visit a different body.)
 
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