Sunday, August 8, 2021

Start Here

I started this blog to document my search for the descent stage of "Snoopy", the Apollo 10 Lunar Module. I thought that I could simulate its orbit and maybe find the crater where it hit the moon. To my surprise, I found instead that Snoopy's orbit was stable over decades. This blog was my attempt to show what I had done, and how I had done it, and hopefully get some feedback on anything I missed. I have to say that traffic was quite light.

I then turned to the ascent stage of the Apollo 11 one knows what became of that little piece of history either. And again, amazingly, the simulated orbit shows a long-term stability very similar to that of the Snoopy stage. Wow! That was in September of 2020, and you might notice that the blog posts stopped around that time. Instead, I focused on writing up the results for peer review and publication, and after some fits and starts I am proud to say that the paper is published.

My intent now is to expand on the Eagle results and continue looking for other interesting objects from that era. 

You can page through the blog posts in order for a "tutorial" on the process I went through. Or skip around to whatever looks interesting.

Love it? Hate it? Don't believe it? Post your (respectful) comments.

Hope you enjoy the material!



  1. I just finished reading the whole thing here, very interesting! Have you considered running your same analysis with the subsatellites that were launched by Apollos 15-17? They are all known to have crashed. Does GMAT predict their crash?

    Also, does your model include small forces like solar radiation pressure?

    1. Thank you. I definitely included solar radiation pressure, and the gravity effects of other planets.

      I have done some modeling for the Apollo 16 LM "Orion" and I find that it probably struck the surface around the same time as the subsatellite, late in May of 1972. (Orion and the satellite were in very similar orbits.) I hope to have more to say about it at some point.

    2. Check out the new post on the Apollo 16 subsatellite called "Reality Check". GMAT does a pretty good job to match the date of impact.

  2. My dad (who passed away in 2017) was the Chief Test Director of the second stage of the Saturn V. I think this is awesome and I truly hope you see the ultimate fruits of your labor - either confirmation of the still-orbiting spacecraft, or a definitive crash site.

    1. Thanks GL. There is definitely more interest now that the Eagle paper passed peer review and was published.

  3. Well, THAT's embarrassing! I just figured out that there were several comments waiting for moderation. Didn't have the right plumbing to be notified about them. Sorry about that folks!


All comments are moderated. Please keep it respectful, non-commercial, and relevant to the topic of the blog. Thanks! Roger.