Thread by @DrPhiltill

Untrue. This does touch on something related that actually happened, which people have apparently distorted and used to prop up the dumb conspiracy theory. I will explain… 1/N

https://twitter.com/mikexgorman/status/1783932452945162277

2/ First I’ll tell you what I know about the videos, then the telemetry.

When I analyzed the plume effects of the lunar landings, starting in the late 1990s and early 2000s, I tracked down the original data. One of the guys on my team worked with Houston to get the videos.

3/ The originals had been converted to digital and this was more convenient for us to use, since we wouldn’t need reel-to-reel NTSC video equipment, so this is what we got. I had high resolution copies of all the landing videos. There was no lost video. It all exists.

4/ The telemetry is more interesting. It still exists, too, but it is nearly impossible to read. When I inquired, they told me the reel-to-reel magnetic tapes were all in storage, and they could get them out for me, but the specific player for those tapes was not at KSC. Worse…

5/ …because they were about 40 years old at the time, they had probably degraded. They said before you use them you have to perform a procedure to bake them so the magnetic material will re-adhere better to the tapes.

6/ They said that I could do this if I needed the data. Then I could take the tapes to Langley where they still had one of the old Apollo-era reel-to-reel tapes so I could read the data. But then I would need to interpret the data stream. Spacecraft have multiple data formats.

7/ There is so much data on a spacecraft but only limited bandwidth in the communications channel, so they do not send all the data all the time. At different parts of the mission they use various “formats” that include only the data needed at that time.

8/ To read the data you need to find out which format they were in for the period of time you are looking. Then you need the document that tells which data words are in each position of the telemetry, and how to convert the 1s and 0s to engineering units. Those documents exist…

9/ in the tech library, so you have to go ask the librarian to pull them out and you have to spend hours reading them to find what you want. Then you have to read mission reports that tell what part of the mission used what format. Then you have to write software to pull out…

10/ …the specific words you want and put them into a shorter file that you can work with for your analysis.

When I considered all this, I decided it was too much work and I didn’t have enough money in my project to do all that on top of the actual analysis that I was planning.

11/ So what we did instead… we found an old-timer at JSC who had worked on the part of the telemetry we needed, and we found in his desk a plot he made on that green engineering graph paper from the days before computers. It had what we needed…

12 (When I say “the days before computers”, I mean before the engineering department had personal computers. They only had hand calculators and graph paper. It was still that way when I was first worked on the Shuttle. Of course Mission Control and the spacecraft had computers.)

13/ So none of the engineers had digital data from Apollo. It was all stored away on tapes. But we found this guy who had plotted exactly what we needed — the height of the lunar module versus time during landing. So that’s what we used.

14/ The telemetry exists, but it is so hard to get that I wonder if now, even 20 years after I tried, whether anybody has spent the funds to bake those tapes, read the formats, and archive it in a more modern digital format. It may literally take an act of Congress to authorize.

15/ A person who has done hard work preserving old space data is @wingod. He has copied and preserved many data tapes from the older robotic missions. Congress should set some money aside to preserve all the Apollo telemetry, too. /end 🧵