posted 03-29-2018 02:07 AM               

For example, before Apollo 8's launch, Jim Lovell very deliberately selected an unnamed lunar region on a lunar map which of course he named "Mount Marilyn" for the purpose of visually spotting this region during the Apollo 8 mission. But why was this?

So at the time of the Apollo 8 mission, had the Sea of Tranquility already been chosen as the landing spot for Apollo 11? If so, was it Lovell's job was to try to find a landmark to aide the landing?

Secondly, as I understand it, Apollo 10's primary mission was to evaluate gravitational fluctuations that might affect the descent of Apollo 11 lunar lander. Apollo 10 also sighted "Mount Marilyn" as a geographical feature that the Apollo 11 astronauts would use.

So, once Apollo 10 had the chance to experience the gravitational fluctuations that Apollo 11 would experience, how did Mission Control and flight planners compensate for these fluctuations? Was it something corrective written into the LM software? Or something added to the simulated landing procedures for Armstrong?

posted 03-29-2018 07:37 AM               

The site for the first launch opportunity on 16 July, would have targeted ALS2-Mare Tranquillitatis. A delay of two days for weather or equipment reasons would have sent them to ALS3-Sinus Medii; another two-day delay (20 July launch) would have resulted in ALS5, a site in Oceanus Procellarum, being targeted.

Flight operations were very concerned about having the optimum lighting conditions at the landing site, hence the target sites moving westward, following the terminator.

posted 03-30-2018 03:47 AM               

Okay so this still goes back to the flight plans for Apollo 8. I have read that Jim Lovell chose the "Mount Marilyn" landmark because it was close to the Sea of Tranquility. Is this correct? And given that there were back-up sites for Apollo 11, did Apollo 8 look at those site as well?

posted 03-30-2018 07:48 AM               

I also seem to recall that there was some issue about how far eastward ALS2 was located. Flight operations was concerned that it was too far east and would not allow adequate tracking and computing of Eagle's trajectory in the interval between appearing over the lunar limb and PDI. ALS1 had been eliminated for this reason.

I believe it was Tom Stafford who suggested Apollo 10 be a test run for landing at ALS2. That way operations could determine if there was a problem or not, and still test the LM under lunar flight conditions.

posted 03-30-2018 11:11 AM               

Some Apollo astronauts assigned to later flights did train at the Cinder Lake Crater Field Complex.

posted 04-02-2018 03:28 AM               

As Headshot noted, there were three lunar landing sites chosen for Apollo 11 all based on when Apollo 11 actually launched.

There was also a lunar landing site committee that was formed in 1968 and as I understand, they were still deciding in June 1969 on where Apollo 11 should land.

Mike Dixon noted that the lunar landing site choices were determined from pictures coming back from the Lunar Orbiter probes.

This brings us to the Apollo 10 mission and specifically, what was the flight path destination for Apollo 10 Lunar Module?

posted 04-02-2018 07:58 AM               

Apollo 8's flight path intentionally took it over ALS1 in Mare Tranquillitus. Images from that mission indicated this site might be "contaminated" with other debris and that it was not a pure "blue" mare. Add that fact to its extreme eastern location and ALS1 was soon out of the running. Apollo 10 flew over ALS2, which turned out to be much more suitable as a "blue" mare representative.