# Astronauts lifting their visors on the Moon **URL:** \ **Category:** Factual Questions\ **Created:** [March 13, 2017, 10:26am UTC](https://boards.straightdope.com/t/astronauts-lifting-their-visors-on-the-moon/782078 "2017-03-13T10:26:38Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [March 14, 2017, 12:01pm UTC](https://boards.straightdope.com/t/astronauts-lifting-their-visors-on-the-moon/782078/21 "2017-03-14T12:01:46Z")
> [@AK84](#): > > Nitpick the Lunar Landings were all made when the sun was relatively low in the sky. It would be either local early “morning” or late “evening” when the Astronauts landed. Not clear why this would matter; with no atmosphere on the moon, solar intensity on the astronauts’ faces would be the same at high noon as at sunrise/sunset. ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [March 14, 2017, 1:00pm UTC](https://boards.straightdope.com/t/astronauts-lifting-their-visors-on-the-moon/782078/22 "2017-03-14T13:00:47Z")
> [@Machine\_Elf](#): > > Not clear why this would matter; with no atmosphere on the moon, solar intensity on the astronauts’ faces would be the same at high noon as at sunrise/sunset. Well per [NASA](https://www.hq.nasa.gov/pao/History/SP-4214/ch6-2.html) > [@](#): > > The second limitation on the longitude of the landing site was the elevation of the sun at the time of landing, which was the major factor considered in choosing the time of launch. To the pilot looking for a safe spot to land within the time the lunar module could hover, it was vital that the sun be high enough in the lunar sky to highlight the surface topography without casting long, confusing shadows, but not so high that all surface detail was washed out. After landing, the lunar explorers would also be hindered by a low or high sun. The moon has no atmosphere to scatter light and therefore shadows are completely black; at either low or high sun angles, visual observations can be difficult. Furthermore, solar heating of the lunar surface varies with sun angle, complicating the problem of protecting the astronauts and the spacecraft against extreme temperatures. Conditions would be best when the sun was 15 to 45 degrees above the horizon. Mission planners could choose a launch time so that the lunar module would land at a time when solar illumination was near optimum. Launch time was subject to the further constraint, however, that lunar missions had to leave the launch pad well before last light in case an aborted launch required emergency recovery operations.6 ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [March 14, 2017, 1:09pm UTC](https://boards.straightdope.com/t/astronauts-lifting-their-visors-on-the-moon/782078/23 "2017-03-14T13:09:07Z")
> [@dtilque](#): > > Did they have any instruments that had LCDs? I’d be surprised if they did, since LCDs were just getting on the market about that time. The electronic displays (part of the DSKY) were electroluminescent displays. High voltage, vacuum, phosphor. The switching of the elements was effected by miniature latching relays driven by the guidance computer. One relay per display element. All the other displays were mechanical. ---
**Author:** ![Omar\_Little](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/omar_little/32/269_2.png) [@Omar\_Little](https://boards.straightdope.com/u/Omar_Little)\ **Post date:** [March 14, 2017, 3:18pm UTC](https://boards.straightdope.com/t/astronauts-lifting-their-visors-on-the-moon/782078/24 "2017-03-14T15:18:19Z")
> [@Darren\_Garrison](#): > > > [@cwthree](#): > > > > All of those pictures clearly show light reflecting off of a transparent visor. Perhaps an outer shell - polarized or darkened against bright light and glare - could be raised while leaving the transparent, airtight inner part in place. > > Yes, most of the Apollo astronauts were for some reason reluctant to open their helmet entirely to the vacuum and die a quick but horrible death. > > Everybody is talking about the [gold sun visor](https://www.hq.nasa.gov/alsj/alsj-LEVA.html), not the whole darn faceplate. This gave me one of the best chuckles I’ve had all week…thanks. ---
**Author:** ![AK84](https://avatars.discourse-cdn.com/v4/letter/a/85e7bf/32.png) [@AK84](https://boards.straightdope.com/u/AK84)\ **Post date:** [March 14, 2017, 3:40pm UTC](https://boards.straightdope.com/t/astronauts-lifting-their-visors-on-the-moon/782078/25 "2017-03-14T15:40:59Z")
Interestingly the later Apollo, Skylab and Apollo-Soyuz saw quite a bit of [hardware being reused.](http://www.collectspace.com/news/news-072604a.html) Flown Space suits [were also reused,](http://www.collectspace.com/review/rickmulheirn/suits0001-lg.jpg) typically in training but also flown again. [Previous page](https://boards.straightdope.com/t/astronauts-lifting-their-visors-on-the-moon/782078.md?page=1)