Don't Panic Geocast

Episode 29 - "Dear NASA, these are a few of our favorite things”

August 7th, 2015


The Orbital Mechanics highlighted how little we know about planetary formation, so let’s talk about Pluto and what we’ve learned from the New Horizons Mission.

Pluto Basics

  • Officially a dwarf planet in the Kuiper belt
  • About 0.18 the radius of Earth
  • Mass 0.178 of the moon’s
  • Very low density
  • Gravity 0.63 g
  • Neptune and Pluto were both predicted to exist from orbital perturbations of Uranus
  • Percival Lowell (founder of Lowell observatory) started the hunt for pluto in 1906.
  • Tombaugh found Pluto using a blink comparison technique
  • Moons of Pluto
  • Orbit is chaotic, we can predict forwards and backwards for several million years, but over the Lyapunov time we have no idea.

New Horizons

The Glitch

  • July 4, 2015 the software went into safe mode
  • Turned out to be a flaw in the timing of the commands in the fly-by prep software.
  • Full functionality restored July 7
  • 9 hour round trip radio delay


  • Bright heart shape observed on the side of the planet during approach is ice (Tombaugh Regio)
  • Nitrogen ice flows like glaciers on Earth. Water ice is very brittle at surface conditions –390 F (–234 C)
  • Active surface is exciting, it’s not a dead planet!
  • Glacier Like Flows News Article from Science


  • As UV light from the sun strikes the thin atmosphere, eventually making tholins that color the surface of the planet
  • Some particles remain suspended, shouldn’t be over 30 km (20 mi) off the sfc.
  • Particles were found to be up to 130 km (81 mi) above the surface
  • Atmospheric pressure is dropping


  • Article
  • Just as geologically exciting as Pluto
  • Likely atmospheric in origin, but could still be geologic
  • Low gravity of Pluto means it won’t hold onto its atmosphere…and Charon is near its same size, so it can pick up gravitationally what Pluto is putting down.
  • Red coating could take less than a million years to form

Near loss of the image

  • Science Magazine Article
  • Team opened the image file, but it was of Charon. They momentarily freaked wondering if the spacecraft wasn’t in the right position.
  • Ended up that they were looking in the wrong directory on a FTP server.


  • 2 months of particle and plasma instrument gathering
  • Will choose between two Kuiper belt objects and head that way to meet in 2019
  • Data transmission home for about 16 months

Getting the data back

  • Tops out about 1 kilobit per second on the 70 m dishes of the deep space network
  • Can double the rate using different polarization transmissions from the two amps “twittas”, but something else must be shut down to have enough power to run both at the same time


Fun Paper Friday

This week’s fun paper sounds a little bit like Jurassic Park to us. What do you think? Blood vessels recovered from fossils.

Schweitzer, Mary H., et al. “Soft-tissue vessels and cellular preservation in Tyrannosaurus rex.” Science 307.5717 (2005): 1952–1955.

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