Project Logs

Collapse

• A Space Map?

  Tom Mladenov • 12/27/2024 at 16:39 • 0 comments

  Came across a cool orbit chart of Apollo 17 on Ebay. You might have seen these as they were drawn up by a subcontractor of NASA with given launch parameters which allowed calculation of the AOS and LOS times - that is the times they are expected to come into and out of contact of the various NASA ground stations during the first earth revolutions.
  
  This one is for Apollo 17 for a December 6th 1972 launch date. Apollo 17 actually launched on December 7th, the cause of the 1-day delay being a failure of the sequencer to command pressurization of the S-IVB liquid oxygen tank.

  
  The map measures roughly 3.5x1.5 feet and has that usual 1970s musty smell which it unleashed once unfurled into this beautiful diorama of orbital mechanics representation.

  The circles on the map represent the "footprint" of the groundstations, if the ground track position of the spacecraft is within this circcle, there is a line-of-sight from the S/C to the ground antennas. They are not perfect circles due to horizon blockages by trees, buildings and mountains. However the red station marked "VAN" does appear to have a clean coverage, in fact this was the Vanguard tracking ship and had great coverage due to no blockages out on the ocean!
  The map shows the first tree Earth revolutions for launch azimuths 72 and 100 degrees (marked in between the tracks), when Apollo 17 launched a day later, the actual launch azimuth was around 82 degrees. The orbit tracks also feature boxes on them with the lapsed time since launch in hours/minutes notation which can be used to read the expected AOS and LOS contact times with the various ground sites.
  

View project log