Chang’e 4 Lunar Orbit a Postmortem

On January 3, 2019, 02:26 UTC Chang’e 4 landed on the far side of the Moon ending over a fortnight of tracking the trajectory of the mission as it left Earth, arrived in lunar orbit made orbital adjustments and then finally landed.  I discuss the results of our tracking attempts focusing mostly on the final analysis where the landing time was predicted and compare that to a final analysis performed after reviewing the crumbs of data shared from Chinese state media videos to see how close we got.

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Basic Orbital Dynamics

There has been a recent surge in interest in a software package written by Cees Bassa known as ‘strf’, Sattools Radio Frequency.  Once over the initial installation and basic usage hump users quickly reach a wall about how to use the software because of a limited understanding of orbital dynamics.  I hope this brief post will help users understand some of the basic concepts so they can use strf as a tool.

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