The Pluto missions

TJohn · 2002-10-25 11:03:20

I came across this from Spacedaily.com

http://www.spacedaily.com/news/nasa-02f1.html

Maybe I'm missing something, but what is the urgency for these missions out to Pluto? I understand that we have to launch probes at a certain time, but this seems to me that it's coming across as "We have got to go now!" type feelings. I maybe reading too much into it.

???

Palomar · 2002-10-25 14:22:11

*Phobos, can you hear me?

I'm surprised Phobos hasn't chimed in on this one.

I would actually like to see probes sent to Europa and Triton, to determine whether or not there's life in the waters beneath the ice.

--Cindy

Byron · 2002-10-25 15:08:45

I came across this from Spacedaily.com
http://www.spacedaily.com/news/nasa-02f1.html
Maybe I'm missing something, but what is the urgency for these missions out to Pluto? I understand that we have to launch probes at a certain time, but this seems to me that it's coming across as "We have got to go now!" type feelings. I maybe reading too much into it.
???

The reason for the urgency for the Pluto mission is due to Pluto's eccentric orbit, which is currently taking it farther away from the sun (it crossed Neptune's orbit in '99 on the way back out.)

It is thought that Pluto has an atmosphere which freezes out during most of its course around the Sun, and an exploratory mission would be far more useful if it gets there before it freezes solid, hence the urgency to get it launched before the end of this decade, otherwise we'll have to wait almost 200 more years before Pluto swings back in again...lol.

But with the terrorist stuff going on, the impending war, etc..I've pretty much lost hope that a Pluto mission will ever be launched...especially if we keep having to pay for Russia's share of the ISS... ???

B

Mark S · 2002-10-26 19:10:22

I'm pretty confident that the Pluto mission will be launched. It has strong congressional support (strong enough to get the mission approved over the objections of the administration.) NASA will not mind funding it because the mission is "only" $850 million.

Sean O' Keefe wanted to hold off on the Pluto mission until an RTG-powered ion thruster was available for the spacecraft. However, this probe will not be able to make the 2006 launch window required to reach Pluto before the atmosphere freezes. Still, this ion-boosted Pluto Orbiter would be a great investment in later years, after the "faster, cheaper, better" Pluto flyby is launched.

Shaun Barrett · 2002-10-26 19:25:18

The notion that we should get to Pluto before the atmosphere collapses due to increasing distance from the 'warmth' of the sun, has met with a glitch!
By studying the light from stars as it passes through Pluto's atmosphere, scientists can gauge the air's density. This has become easier in recent years because Pluto is currently passing in front of star fields with more stars in them, hence more opportunities to do measurements.

The 'glitch' I mentioned is that these measurements show Pluto's atmosphere is actually THICKENING quite substantially as Pluto recedes further from the sun!! This, of course was completely unexpected.
The only explanation so far put forward is that Pluto's 'seasons' have a lag period built into them, rather like Earth's. In other words, the warmest conditions occur just after the period of greatest insolation.
On Earth, in say the northern hemisphere, we find that July and August are warmer than May and June, even though the point of maximum solar input per square metre of Earth's surface occurs at the end of June (the summer solstice). Here, of course, we have oceans which act as heat sinks. They warm up slowly as the solstice approaches, and then give up their heat after the solstice, thus supplementing the total energy available in late summer and keeping things warmer.

But no comprehensive theory has been suggested yet to fully explain how Pluto manages to pull off the same trick, given the very different environmental conditions.

But still, we shouldn't look a gift horse in the mouth. Pluto's apparent 'seasonal' lag may give us quite a few extra years to get our act together and send a probe!!

Phobos · 2002-10-27 00:14:22

*Phobos, can you hear me?
I'm surprised Phobos hasn't chimed in on this one.
I would actually like to see probes sent to Europa and Triton, to determine whether or not there's life in the waters beneath the ice.
--Cindy

ACK! I don't visit New Mars for a day and I miss my chance for glory! It looks like others have already beat me to the punch though, we gotta get to Pluto in a damn hurry before its atmosphere freezes out and just because it'd be nice to be alive by time it arrives! Onward to Pluto!

The 'glitch' I mentioned is that these measurements show Pluto's atmosphere is actually THICKENING quite substantially as Pluto recedes further from the sun!! This, of course was completely unexpected.

Actually it wasn't completely unexpected . Here's a little snip I took from a news article.

"David Tholen, an astronomer at the University of Hawaii who measured the size of Pluto in the late 1980s using a series of occultations and eclipses involving Pluto's satellite, noted that even though Pluto was closest to the sun in 1989, a warming trend 13 years later shouldn't be unexpected. "It takes time for materials to warm up and cool off, which is why the hottest part of the day on Earth is usually around 2 or 3 p.m. rather than local noon, when sunlight is the most intense," Tholen said. Because Pluto's year is equal to about 250 Earth years, 13 years after Pluto's closest approach to the Sun is like 1:15 p.m. on Earth. "This warming trend on Pluto could easily last for another 13 years," Tholen estimated. "

So I guess Pluto is just adding miniscule amounts of heat to its retained "warmth" and rapidly beginning its descent into a freezing hell from there. Or maybe the Eskimos that live there have resorted to burning coal for energy. Who knows, if they launch the probe early enough maybe we'll know for sure.

Shaun Barrett · 2002-10-27 18:51:37

A nice come back on that, Phobos. I stand corrected on the degree of unexpectedness. That David Tholen is one smart cookie and must be preening his feathers now his prediction has been validated!

Actually, since my last post here, I've been thinking about Earth's oceans being a heat sink and affecting our climate. It occurred to me that maybe Pluto has oceans too.
I know they've been hypothesising that Titan could have seas of liquid hydrocarbons and 'continents' of granite-hard water ice.
What kind of hydrocarbon, if any, could remain liquid under Plutonian conditions? I was wondering whether Pluto might have hydrocarbon oceans which, for at least the perihelion part of its orbit, would be liquid, but which might largely freeze during the aphelion phase?
Such a freeze/thaw cycle could provide a mechanism for the seasonal temperature lag we're seeing.

I have no idea what I'm talking about, of course! These are just random thoughts.
Am I just dreaming, or is it feasible?
:0

Palomar · 2002-10-27 20:12:25

Actually, since my last post here, I've been thinking about Earth's oceans being a heat sink and affecting our climate. It occurred to me that maybe Pluto has oceans too.
I know they've been hypothesising that Titan could have seas of liquid hydrocarbons and 'continents' of granite-hard water ice.
What kind of hydrocarbon, if any, could remain liquid under Plutonian conditions? I was wondering whether Pluto might have hydrocarbon oceans which, for at least the perihelion part of its orbit, would be liquid, but which might largely freeze during the aphelion phase?
Such a freeze/thaw cycle could provide a mechanism for the seasonal temperature lag we're seeing.
I have no idea what I'm talking about, of course! These are just random thoughts.
Am I just dreaming, or is it feasible?
:0

*Erm...you probably know more about this sort of thing than I do, Shaun, but Pluto is so far "out there." Any water would be frozen solid, I should think. Is there any sort of natural chemical that would prevent absolute freezing in such severe coldness?

By the way, I have a chart in my pet astronomy book [the reproduction of the one I had as a kid, which I've mentioned before]; as seen from Pluto, our sun is just a bright star; no disc detectable.

--Cindy

Phobos · 2002-10-27 22:23:11

Actually, since my last post here, I've been thinking about Earth's oceans being a heat sink and affecting our climate. It occurred to me that maybe Pluto has oceans too.
I know they've been hypothesising that Titan could have seas of liquid hydrocarbons and 'continents' of granite-hard water ice.
What kind of hydrocarbon, if any, could remain liquid under Plutonian conditions? I was wondering whether Pluto might have hydrocarbon oceans which, for at least the perihelion part of its orbit, would be liquid, but which might largely freeze during the aphelion phase?
Such a freeze/thaw cycle could provide a mechanism for the seasonal temperature lag we're seeing.

Wow, imagine landing on Pluto to find a giant ocean reflecting pinpoints of starlight off its calm surface. I think it's conceivable there could be oceans of liquid methane on Pluto at some point in it's orbit since its atmosphere is composed of gaseous methane. I sometimes wonder if the global warming might not have something to do with the dark/light areas that have been observed on Pluto. Perhaps Pluto's tilt gives more of these dark areas more exposure to the sun during its retreat into winter and allows it to warm up some. That theory probably makes no sense , but I thought I'd just throw it out there.

*Erm...you probably know more about this sort of thing than I do, Shaun, but Pluto is so far "out there." Any water would be frozen solid, I should think. Is there any sort of natural chemical that would prevent absolute freezing in such severe coldness?

Certainly, heck Pluto's atmosphere is still a gas it's not even to the liquid stage yet even though it'll probably just condense straight into a solid. But if you mean during Pluto's absolute coldest moments, I'm not sure. Pluto gets down to around 30 Kelvins during it's coldest moments, just a hair above absolute zero which is the temperature at which all molecular motion ceases. Methane and Nitrogen become liquids at around 80 kelvins but I'm not sure what their freezing points are even though it must be above 30 Kelvins since they freeze on Pluto. Anyways, I think it'd be a sight to be standing there on Pluto watching flakes of "snow" come gently falling down to the surface. It'd be a Zen moment.

Shaun Barrett · 2002-10-28 01:01:42

After a quick look around on Google, I've given up on finding anything that could form a liquid ocean on Pluto, except nitrogen. And, even then, nitrogen is unlikely to be liquid for much of Pluto's year (if at all) because of its melting point.
It seems to be the general consensus of opinion that Pluto's average surface temperature is about 40 deg.K (or about -233 deg.C), ranging between maybe 30 and 60 deg.K. But nitrogen doesn't melt until you get up to 63.1 deg.K.

I think I may have to withdraw my wild speculation about oceans on Pluto!

And I think our friend with the axe in his head may have to reconsider his largely unsubstantiated hypothesis that groups of eskimos have taken up residence there, too!!

Phobos · 2002-10-28 18:04:20

And I think our friend with the axe in his head may have to reconsider his largely unsubstantiated hypothesis that groups of eskimos have taken up residence there, too!!

Oh no, I don't think he could bare the news. He's probably been waiting his entire life to meet the Eskimos that live up there.

TJohn · 2002-11-01 12:19:18

Here's another link concerning the Pluto-Kuiper Belt Mission:

http://www.floridatoday.com/news/space/ … 2pluto.htm

Turns out that the NASA originally wanted to wait on this mission until better propulsion systems were developed, but Congress and the public(???) said let's go ASAP. The first full paragraph is what made me LOL. It said that "When NASA threatened to cancel sending an unmanned expedition to Pluto, scientists and the public complained to Congress. After a petition and more than 10,000 letters, lawmakers in Washington overrode NASA's wishes two years in a row, force-feeding the agency the money necessary to pay for a robotic mission to the icy planet." I'm pretty sure that the Mars Society and other organizations have petioned(sp) about the same amount for a manned Mars mission, but nothing happens. I guess it's good to have Congress on your side.

Phobos · 2002-11-01 20:43:25

It seems strange how NASA is so opposed to a Pluto mission when everybody else wants one. I know NASA is trying to focus on new forms of propulsion but it's not like their budget is being axed or they'll have to give up personnel who are key to other projects to get the Pluto mission going. Anyways I found another reason why we should get to Pluto as early as possible, a less obvious one:

"The second reason is to map as much of Pluto and Charon as possible. On Earth, the North Pole and other areas above the Arctic Circle have half a year of night and half a year of daylight. In the same way, parts of Pluto or Charon never see the Sun. The longer we wait, the more of Pluto and Charon are shadowed in the "arctic night," impeding the spacecraft?s ability to take pictures in reflected sunlight. "

I guess if we don't get to Pluto fast enough a lot of Pluto will be in perpetual dark and not as accessible to the probe's instruments as it otherwise could have been.

Phobos · 2002-12-14 02:20:24

A nuclear rocket might have gotten the probe to Pluto faster but from everything I read adding such technology to the probe would have increased it's cost considerably and on top of that the more a project waits the more likely it is to get canned or delayed. I think we should launch it asap even though it's using primitive chemical rockets and gravity assists to push it.

Palomar · 2003-04-12 18:32:27

*Pluto visit in NASA plans -- for real!

http://dsc.discovery.com/news/briefs/20 … pluto.html

http://www.spacedaily.com/news/outerplanets-03f.html

--Cindy

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#1 2002-10-25 11:03:20

Re: The Pluto missions

#2 2002-10-25 14:22:11

Re: The Pluto missions

#3 2002-10-25 15:08:45

Re: The Pluto missions

#4 2002-10-26 19:10:22

Re: The Pluto missions

#5 2002-10-26 19:25:18

Re: The Pluto missions

#6 2002-10-27 00:14:22

Re: The Pluto missions

#7 2002-10-27 18:51:37

Re: The Pluto missions

#8 2002-10-27 20:12:25

Re: The Pluto missions

#9 2002-10-27 22:23:11

Re: The Pluto missions

#10 2002-10-28 01:01:42

Re: The Pluto missions

#11 2002-10-28 18:04:20

Re: The Pluto missions

#12 2002-11-01 12:19:18

Re: The Pluto missions

#13 2002-11-01 20:43:25

Re: The Pluto missions

#14 2002-12-14 02:20:24

Re: The Pluto missions

#15 2003-04-12 18:32:27

Re: The Pluto missions

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