Ultima Thule Flyby on New Year’s Eve

NASA’s New Horizons spacecraft will welcome the New Year with a flypast of the most distant solar system object ever visited. New Horizons made headlines when it flew past Pluto and Charon in 2015 and is now headed for a rendezvous with the Kupier Belt object  “Ultima Thule”.

Here are 19 facts about this encounter to start the year 2019.

  1. The closet approach is predicted to occur at 09:33 PM on Dec 31st, 2018 PST.
  2. Ultima Thule was discovered in 2014, 8  years after the launch of the New Horizons spacecraft.
  3. Ultima Thule is approximately 37 km across, about the same distance as a drive from Point Grey to Coquitlam.
  4. At its closet approach, New Horizon is expected to be  3,500 km from Ultima Thule. This is 3 times closer than it was to Pluto and should result in higher resolution images and spectroscopic data.
  5. Signals from Ultima Thule take about 6 hours to reach Earth
  6. Ultima Thule formed in middle of the Kupier Belt where temperatures are close to absolute zero and it is too small to have a geologic engine like Pluto. Hence, scientists expect it to be a  well-preserved sample of a planetary building block.
  7. The first health status signal is expected to be received around 07:00 am PST on Jan 1st with the first image data coming in a few hours later. Look for the first images to be released on Jan 2nd, 2019.
  8. New Horizons will collect about 50 GB of data during its flypast but it will take about 20 months to send all that data back to Earth.
  9. Analysis of recent light curves haven’t revealed the variations predicted by previous observations. Alan Stern, the principle investigator, has called this discrepency “Ultima Thule’s first puzzle”.
  10. The orbit of Ultima Thule was not well established so New Horizons has been imaging it and has made several course correction maneuvers to adjust for differences in its predicted position vs its actual position. The last correction was a short 27 second burn on Dec 20th, 2018.
  11. New Horizons entered “Encounter Mode” on Boxing Day so its on-board software will now handle any problems without intervention from Earth.
  12. A Hazards Team scoured images for signs of moons or other dangerous debris along New Horizons’ path but gave the “all clear” signal in December 2018 for a close flyby.
  13. Ultima Thule may be shaped like a rubber ducky or possibly two separate bodies based on observations made during its occultation of a star in 2017.
  14. Ultima Thule’s official designation is  2014 MU69.
  15. The apparent magnitude of Ultima Thule is 27: too faint for all but the most powerful telescopes.
  16. The name “Ultima Thule” was nominated by about 40 people in a public campaign for selecting a nickname. It refers to a distant place located beyond the borders of the known world.
  17. Ultima Thule orbits the Sun once every 295 years.
  18. Ultima Thule is not visible in the night sky on Dec 31st as it is located in the constellation Sagistarius and will be less than  5° from the Sun.
  19. It will reach naked eye brightness (magnitude 6) as seen from New Horizons’ point of view 3-4 hours before closest approach.
New Horizons Ultima Thule Encounter Timeline

For more information on the New Horizons mission, including fact sheets, schedules, video and images, visit: http://www.nasa.gov/newhorizons and http://pluto.jhuapl.edu.