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New Horizons


r4pt0r

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http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20151026b

Today, New Horizons performed its 2nd maneouvre out of the 4 needed to encounter 2014 MU69 in January 2019. Today's maneouvre was the largest ever performed by New Horizons, lasting around 25 minutes. If my calculations are correct, the delta-v was 15-16 m/s.

- - - Updated - - -

EDIT: actually, the maneouvre happened yesterday, starting from 13:30 EDT | 17:30 UTC.

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What will its orbital parameters be after the 2019 flyby?

The orbital parameters of New Horizons? Well, it's on an escape trajectory, so it should escape the heliosphere around the 2030s.

Or did you mean the orbital parameters of 2014 MU69? Well, obviously they will remain unchanged after the flyby. You can find some of its orbital parameters on Wikipedia

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Somebody here mentioned that because Pluto has old areas as well as young, it proves geological activity is only local and global tectonics is dead. First, tectonics can be global, it doesn't have to specifically be plate tectonics. Second, Earth has areas that are billions of years old too http://earthquake.usgs.gov/data/crust/age.html .

Nafnlaus on the Unmanned Spaceflight forum pointed out it might take just 18 meters of solid nitrogen to provide enough pressure for liquid nitrogen http://www.unmannedspaceflight.com/index.php?s=&showtopic=8060&view=findpost&p=224056 . Solid nitrogen sinks in liquid nitrogen, but it is also highly porous as you can see here

. My bet is on nitrogen slush or glaciers with little capilaries with liquid nitrogen in them. A little known fact is that practically all ice on Earth, or more properly, Earth temperatures (basically, warmer than -90 degrees Celsius), contains some liquid water, even hard, glacier ice. This is the reason why microbes live even in Antarctic glaciers (found in deep ice cores) and on frozen rocks in Antartic dry valleys. Water ice is a hard rock at Pluto temperatures, but nitrogen ice is near its melting point, actually exceeding it and boiling in the summer https://blogs.nasa.gov/pluto/2015/10/23/a-planet-for-all-seasons/ , so nitrogen, methane, and CO ice take the role of "glacier ice" on Pluto while water ice is like sillicon dioxide on Earth - rock. I elaborated more in my post here http://www.unmannedspaceflight.com/index.php?s=&showtopic=8103&view=findpost&p=227686 where I found analogies of landforms on Io of all the places.

The latest photos are very interesting. I don't think even the "old" terrain of Pluto is really that old or inactive. The craters are clearly deformed and there are deep tectonic features or water "lava" flows there. Remember, on Ariel, "lava" of liquid water- ammonia mixture has formed some very interesting landforms and that is a body more like Charon in size . It is a shame we only have Voyager images of the Uranian moons. Just because a surface is billions of years old doesn't mean there are no changes - it is only the general age of the crust. The latest recorded impacts on the Moon occured in 2013 and 5 tons of cometary particles are thought to impact the Moon everyday, so even a surface 3.5 billion years old can have younger features. The Cthulu regio is clearly not as resurfaced as Sputnik Planum but that is probably because it is mostly composed of hard water ice and not lack of activity. You can clearly see on the borders of Cthulu Regio-Sputnik Planum that Sputnik Planum is "trying" to encroach on the Cthulu Regio and volatiles ices have already filled some craters.

Also, Plutonian atmosphere is still about 100 billion times thicker than that of the Moon - it is collisional and can support wind. You could even feel the wind as the pressure is roughly like a dollar bill resting on your palm. Solar wind is about trillion times less dense than that.

Edited by MichaelPoole
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Here are 2 good articles on atmospheres I found today:

http://beyondearthlyskies.blogspot.sk/2015/05/detection-of-oxygen-atmosphere-around.html

http://www.planetary.org/blogs/emily-lakdawalla/2015/04081101-a-moon-with-atmosphere.html

So you can have a collisional atmosphere with weather and wind down to dozens of picobars pressure range.

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By the way, seeing small meteors impact Pluto would be interesting because it has such a high scale height (60 km), so 60 km high on Pluto, the atmospheric pressure would be just 2.71828x lower than on the ground. The ground pressure is roughly 10 microbars. Meteors start burning up 76 to 100 km from Earth and usually burn up completely at 50 to 95 km. Earth's mesosphere (50-80 km up) has a similiar pressure to Pluto at ground level. So, maybe Pluto has "ground bursts", meteors exploding near the ground like little grenades. I don't think people should wave away an atmosphere's effects just because it is thinner than ours at ground level. Sure, you might compare it to vacuum made on Earth but most "general purpose" vacuums suck - the pressure in a lightbulb is 0.7 atm, on Mt. Everest it is 0.337 atm. So by lightbulb manifacturing standards, Mt. Everest is surrounded by a vacuum.

This can also be an effect on future landers. They might use aerobreaking even if just to slow down a little. Actually, considering the pressure 60 km from Pluto is not much smaller than pressure on the ground, there might be some regular meteors as well, and reentry effects might be more appearant than you might think. Don't forget - LEO orbital stations and satellites have to constantly correct their altitude or they fall down and burn up in the atmosphere. Pressure at LEO is much lower than on Pluto. As for optical effects, it is no surprise Pluto's atmosphere is visible considering the Moon has almost no gas atmosphere but a bit of electrostatically charged dust is enough to make visible crepuscular rays visible both to astronauts and space probes https://en.wikipedia.org/wiki/Atmosphere_of_the_Moon https://en.wikipedia.org/wiki/Lunar_soil#Moon_dust_fountains_and_electrostatic_levitation http://science.nasa.gov/science-news/science-at-nasa/2005/30mar_moonfountains/ http://www.nasa.gov/centers/goddard/images/content/455854main_Surveyor_LHG_obs_selection.jpg . Considering Pluto's atmosphere is full of aerosol fog and is more than billion times thicker than the Moon's, it is no surprise it is very well visible. Solar corona is trillion times more rarefied than out atmosphere yet I saw it with my own eyes during a full solar eclipse. Comet's outer comas and tails are even more rarefied yet they can be very bright.

Edited by MichaelPoole
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A recap of today's discoveries:

Two possible criovulcanoes have been spotted south of Sputnik Planum. The two mountains (Wright and Piccard Montes) are respectively 3 and 5.5 km tall and 150 km wide. The sorrounding hummocky terrain suggests possible criovulcanic flows, but who knows.

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So far 1070 craters have been mapped, and their distribution varies widely. This suggests that there are some regions of intermediate age (like western lobe of Spuntik Planum, maybe 1 bln years old) bewteen the very ancient ones (e.g. Cthulhu, 4 bln years old) and the younger ones (e.g. Spuntik Planum, 10 mln years old).

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This also suggests that in the early Kuiper Belt there could have been less small (<1 mile) bodies. This would mean that KBOs were born already quite big (relatively), which would mean that 2014 MU69 would be even more pristine than thought. Great!

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In a quite enigmatic result, the REX radio experiment found a surface temperature of 30 K at the beginning of the occultation and one of 50 K at the end of the occultation. (However it could just be different surface albedos messing the readings up).

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Now onto the moons. Turns out Hydra completes 88.9 rotations for every revolution around the system barycenter - a solar system record!

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Also, turns out that Nix's rotation axis is tilted 132 degrees, meaning it basically rotates on itself backwards.

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Finally, at least Kerberos and Hydra seem to have been originated by the merging of two or more smaller bodies. Pluto had more moons in the past?

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I really, really hope the spoiler tags work. Also, please bare in mind that we have only 20% of the data downloaded, and maybe even less analyzed by the scientists. This mission is seriously cool.

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