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Fresh Look at New Horizons Data Shows Plutos Far Side in Unprecedented Detail

50 points by makaimc 7y ago

crocal 7y ago
Anyone else would like to join a trek from Balrog to Cthulhu on a frosty Plutonian summer day?
- Ididntdothis 7y ago
  You could take a nice swim in a nitrogen lake :)
droithomme 7y ago
Interesting about the 1000 ft tall ice shards. The article mentions a possible orbiter mission to Pluto. Is it even possible? The spacecraft would have to either massively decelerate at the end of the mission, meaning take a huge amount of fuel with itself, or would have to travel much slower, with the mission possibly taking decades to arrive. In 2017 some astrophysicists met to discuss a possible orbiter mission: https://www.space.com/36697-pluto-orbiter-mission-after-new-horizons.html https://www.space.com/36697-pluto-orbiter-mission-after-new-... They've also discussed a Charon lander, but seem to be now preferring an orbiter with a complex dual-object orbit. In 2017 they decided to firm up the plan so they can make a formal proposal at a 2020 meeting where NASA decides what it wants to do over the next decade. So we likely will hear a lot about how this would work next year.
- drjesusphd 7y ago
  "Travelling much slower" isn't really an option either. By the time a craft encounters Pluto, the problem is that it's going too slow. It then has to match the (higher) orbital speed, and Pluto's gravity is not helping much.
  - droithomme 7y ago
    You bring up a good point regarding the relative speeds. Pluto on average travels 4.7 km/sec or 16,800 km/hr. New Horizons, on a 9 yr mission to arrive, was traveling 50,700 km/hr as it passed Pluto. So it was going much faster than Pluto, however it was passing almost orthogonal to Pluto's trajectory. It seems an orbiter would want to arrive using some complex slingshot mission around various solar system objects, and taking a catch up trajectory that approaches Pluto more tangentially to its orbit rather than orthogonally. That seems more doable than when I first balked at this. Since gravity assist/slingshots can be used to slow down as well as speed up perhaps it zooms out there fast, then slingshots to nearly meet the speed and direction of Pluto, meeting up with it at its orbital path sideways and only needing a small correction at the end to insert itself into orbit.
    - T-hawk 7y ago
      Matching speeds to the target object isn't all that difficult, right. The problem is the travel time becomes enormous to a distant target object, because it's going so slow comparatively. Pluto's orbital period is 248 years. If you aim to match its velocity when you arrive, the journey takes a significant fraction of those 248 years. Compare Mars, where the orbital period is 22 months, and a Hohmann transfer orbit takes 9. A similar trajectory to Pluto would be on the order of 80 to 90 years. It's not just about the magnitude of the speed vector, it's also the direction. To match and orbit Pluto, you need that 4.7 km/sec to be tangent to the sun. You need to start out slow enough so that your radial velocity can fall to zero by the time you get there. You can't apply more radial velocity to get there faster, either by launch or slingshot, if there isn't equivalent fuel or mass to decelerate you; you'll overshoot as New Horizons did.
      - burfog 7y ago
        We now have ion thrusters, which are great for when you need a huge velocity change but can take your sweet time to do it.
- mannykannot 7y ago
  It has been suggested that the ice shards form through sublimation, like the penitentes of the Andes. https://science.nasa.gov/plutos-bladed-terrain https://science.nasa.gov/plutos-bladed-terrain https://en.wikipedia.org/wiki/Penitente_(snow_formation) https://en.wikipedia.org/wiki/Penitente_(snow_formation)
- avian 7y ago
  > The article mentions a possible orbiter mission to Pluto. Is it even possible? I can't read the space.com article about the orbiter mission, but a lander concept was proposed in 2017. Their idea was to use aerobreaking with a giant inflatable balloon, using New Horizon data on atmosphere density as a guideline for the maneuver: https://www.spaceflightinsider.com/missions/solar-system/pluto-lander-concept-unveiled-global-aerospace-corporation/ https://www.spaceflightinsider.com/missions/solar-system/plu...
jessriedel 7y ago
My personal favorite astronomical image of all time is this view taken by New Horizon during its retreat from Pluto: https://en.wikipedia.org/wiki/File:PIA19948-NH-Pluto-Norgay-Hillary-Mountains-2050714.jpg https://en.wikipedia.org/wiki/File:PIA19948-NH-Pluto-Norgay-... It shows atmospheric haze and the curvature of the planet in the same picture as stark terrain features. (It's a real image; not a reconstructed 3D visualization.) The Hillary Montes break into the limb (skyline) near the top of the image.
- droithomme 7y ago
  Thanks, I had not seen that image before. It's amazing that Pluto has an atmosphere. Was this suspected before the New Horizon's mission? I seem to recall it once being presented as considered a cold rock with no interesting features or possible atmosphere.
  - yaks_hairbrush 7y ago
    It was indeed established that Pluto had an atmosphere before the New Horizon flyby. The atmosphere is mostly seasonal. The air freezes when Pluto is far from the sun, and sublimates again when it's near.
    - lmkg 7y ago
      Thank you for reminding me how strange the universe can be sometimes.
- yig 7y ago
  Any idea why it appears black and white? The links say it was taken with the "Multispectral Visual Imaging Camera (MVIC)", whose description suggests it can capture in visible spectra. Is Pluto really made of grey?
  - jessriedel 7y ago
    I don't know why. My best guess is that it's low lighting, and there isn't much color information available. I think I've seen a colorized version somewhere, but can't remember if the colors were authentic. Very interested if someone could track that down.
api 7y ago
I love that there is a Cthulhu region, especially given that Pluto is Yuggoth. :)
Ididntdothis 7y ago
Does anyone know what shutter speeds and ISO they are using for such pictures? It must be f...ing dark out there. Or do concepts like shutter speed and ISO not make sense for the type of camera they are using?
- dr_zoidberg 7y ago
  Shutter speed yes, ISO... I think you can check the gain of the sensor used for an image, which is a similar concept. You can see this information on the FITS files ("the raws") metadata.

50 points by makaimc 7y ago

crocal 7y ago

Anyone else would like to join a trek from Balrog to Cthulhu on a frosty Plutonian summer day?

Ididntdothis 7y ago
You could take a nice swim in a nitrogen lake :)

droithomme 7y ago

Interesting about the 1000 ft tall ice shards. The article mentions a possible orbiter mission to Pluto. Is it even possible? The spacecraft would have to either massively decelerate at the end of the mission, meaning take a huge amount of fuel with itself, or would have to travel much slower, with the mission possibly taking decades to arrive. In 2017 some astrophysicists met to discuss a possible orbiter mission: https://www.space.com/36697-pluto-orbiter-mission-after-new-horizons.html https://www.space.com/36697-pluto-orbiter-mission-after-new-... They've also discussed a Charon lander, but seem to be now preferring an orbiter with a complex dual-object orbit. In 2017 they decided to firm up the plan so they can make a formal proposal at a 2020 meeting where NASA decides what it wants to do over the next decade. So we likely will hear a lot about how this would work next year.

drjesusphd 7y ago
"Travelling much slower" isn't really an option either. By the time a craft encounters Pluto, the problem is that it's going too slow. It then has to match the (higher) orbital speed, and Pluto's gravity is not helping much.
- droithomme 7y ago
  You bring up a good point regarding the relative speeds. Pluto on average travels 4.7 km/sec or 16,800 km/hr. New Horizons, on a 9 yr mission to arrive, was traveling 50,700 km/hr as it passed Pluto. So it was going much faster than Pluto, however it was passing almost orthogonal to Pluto's trajectory. It seems an orbiter would want to arrive using some complex slingshot mission around various solar system objects, and taking a catch up trajectory that approaches Pluto more tangentially to its orbit rather than orthogonally. That seems more doable than when I first balked at this. Since gravity assist/slingshots can be used to slow down as well as speed up perhaps it zooms out there fast, then slingshots to nearly meet the speed and direction of Pluto, meeting up with it at its orbital path sideways and only needing a small correction at the end to insert itself into orbit.
  - T-hawk 7y ago
    Matching speeds to the target object isn't all that difficult, right. The problem is the travel time becomes enormous to a distant target object, because it's going so slow comparatively. Pluto's orbital period is 248 years. If you aim to match its velocity when you arrive, the journey takes a significant fraction of those 248 years. Compare Mars, where the orbital period is 22 months, and a Hohmann transfer orbit takes 9. A similar trajectory to Pluto would be on the order of 80 to 90 years. It's not just about the magnitude of the speed vector, it's also the direction. To match and orbit Pluto, you need that 4.7 km/sec to be tangent to the sun. You need to start out slow enough so that your radial velocity can fall to zero by the time you get there. You can't apply more radial velocity to get there faster, either by launch or slingshot, if there isn't equivalent fuel or mass to decelerate you; you'll overshoot as New Horizons did.
    - burfog 7y ago
      We now have ion thrusters, which are great for when you need a huge velocity change but can take your sweet time to do it.
mannykannot 7y ago
It has been suggested that the ice shards form through sublimation, like the penitentes of the Andes. https://science.nasa.gov/plutos-bladed-terrain https://science.nasa.gov/plutos-bladed-terrain https://en.wikipedia.org/wiki/Penitente_(snow_formation) https://en.wikipedia.org/wiki/Penitente_(snow_formation)
avian 7y ago
> The article mentions a possible orbiter mission to Pluto. Is it even possible? I can't read the space.com article about the orbiter mission, but a lander concept was proposed in 2017. Their idea was to use aerobreaking with a giant inflatable balloon, using New Horizon data on atmosphere density as a guideline for the maneuver: https://www.spaceflightinsider.com/missions/solar-system/pluto-lander-concept-unveiled-global-aerospace-corporation/ https://www.spaceflightinsider.com/missions/solar-system/plu...

jessriedel 7y ago

My personal favorite astronomical image of all time is this view taken by New Horizon during its retreat from Pluto: https://en.wikipedia.org/wiki/File:PIA19948-NH-Pluto-Norgay-Hillary-Mountains-2050714.jpg https://en.wikipedia.org/wiki/File:PIA19948-NH-Pluto-Norgay-... It shows atmospheric haze and the curvature of the planet in the same picture as stark terrain features. (It's a real image; not a reconstructed 3D visualization.) The Hillary Montes break into the limb (skyline) near the top of the image.

droithomme 7y ago
Thanks, I had not seen that image before. It's amazing that Pluto has an atmosphere. Was this suspected before the New Horizon's mission? I seem to recall it once being presented as considered a cold rock with no interesting features or possible atmosphere.
- yaks_hairbrush 7y ago
  It was indeed established that Pluto had an atmosphere before the New Horizon flyby. The atmosphere is mostly seasonal. The air freezes when Pluto is far from the sun, and sublimates again when it's near.
  - lmkg 7y ago
    Thank you for reminding me how strange the universe can be sometimes.
yig 7y ago
Any idea why it appears black and white? The links say it was taken with the "Multispectral Visual Imaging Camera (MVIC)", whose description suggests it can capture in visible spectra. Is Pluto really made of grey?
- jessriedel 7y ago
  I don't know why. My best guess is that it's low lighting, and there isn't much color information available. I think I've seen a colorized version somewhere, but can't remember if the colors were authentic. Very interested if someone could track that down.

api 7y ago

I love that there is a Cthulhu region, especially given that Pluto is Yuggoth. :)

Ididntdothis 7y ago

Does anyone know what shutter speeds and ISO they are using for such pictures? It must be f...ing dark out there. Or do concepts like shutter speed and ISO not make sense for the type of camera they are using?

dr_zoidberg 7y ago
Shutter speed yes, ISO... I think you can check the gain of the sensor used for an image, which is a similar concept. You can see this information on the FITS files ("the raws") metadata.