New Horizons probe meets Pluto

/ 13 July 2015
Submitted by webteam.rascto… on 13 July 2015

The New Horizons spacecraft passed Pluto on July 14. It will not send much information to Earth right away because all the instruments and the high gain antenna dish are fixed to the spacecraft. If a camera is taking a picture, the dish cannot also be pointed to Earth to send information back.

New Horizons Probe

Diagram from New Horizons press kit

The main instruments are:

  • Alice UV spectrometer
  • Ralph Visible and IR imager, IR spectrometer (not acronyms, someone was a fan of the Honeymooners)
  • SDC measures dust
  • LORRI telescopic imager
  • SWAP solar wind
  • PEPPSI mass spectrometer for escaped particles
  • REX part of dish to analyze radio signals, especially pure tones broadcast from Earth

Pluto System

The Pluto system is tilted almost towards the Sun and us. Charon so heavy and close to Pluto that both move around spot outside Pluto. There are 4 other moons detected so far by the Hubble Space telescope, all far above Charon, but in the same plane.

Flyby Pluto Diagram

Diagram from New Horizons Press Kit

Timeline of events 

  1. Mon. July 13, before 11:15 pm EDT (8h 35 min before closest approach)
    1. Last Image of Pluto showing the full planet taken with LORRI.
    2. 3.8 km per pixel.
  2. Mon. July 13, after 11:15 pm EDT
    1. Image sent to Earth.
    2. The first part arrives 4 hours 25 minutes later or 3:40 am on Tuesday.
    3. Given a 52-minute download time it might be ready soon after 4:32 EDT.
  3. Tues. July 13, about 11:30 pm EDT
    1. Deep Space Network starts broadcasting a pure tone signal towards Pluto.
    2. Spacecraft accurately measures speed compared to Earth from Doppler shift.
  4. Tuesday 7:30 am NASA briefing.
  5. Tuesday 7:50 am EDT
    1. Closest approach to Pluto. We won’t know what is happening because the antenna won’t be pointing to Earth.
  6. Tuesday 8:04 am EDT (14 min after)
    1. Closest approach to Charon.
  7. Tuesday 8:52 am EDT (50 min after).
    1. Occultation of Sun, then Earth by Pluto.
    2. The antenna will point to Earth and will detect changes in the radio signal from Earth giving the size of the planet and information about the atmosphere.
  8. Tuesday 10:05 am EDT (2 h 15 min after).
    1. Occultation of Sun, then Earth by Charon.
  9. Tuesday 4:50 pm EDT (9 h after)
    1. New Horizons sends 18 minutes of engineering data back to Earth.
    2. Reaches us at 9:02 pm EDT.
    3. NASA TV briefing after that.
  10. Following days
    1. Scientific data and reduced images sent back.
    2. Later full versions will be sent.
  11. Oct. – Dec. 2016 All data sent back.
  12. Jan. 2019 New Horizons flies by another Kuiper Belt object.