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# Tag Info

191

This is the Apollo 11 photo designated AS11-40-5925, a popular shot with moon landing deniers. The camera is facing generally north-north-west. The sun is low in the sky, about 10º-15º above the horizon on the east. The silver pole in the upper right of the photograph is pretty much straight up, casting shadow in the expected direction. The landing leg in ...

109

(A) who (if anyone) was the first human to actually be asleep (that is to say, presumably inside the lander) - not just a scheduled sleep time - on the Moon? It depends on your definition of sleep. Maybe Buzz Aldrin, curled on the floor of the LM cabin: The best Aldrin managed was a “couple hours of mentally fitful drowsing.” Armstrong simply stayed ...

24

Power: The Moon has a night that lasts for 14 Earth days, and it gets really cold during the night. This makes it difficult/expensive to design a rover that can last through the night: you really need a radioisotope power source (RTG) to provide at least heat overnight. Mars, on the other hand has a day/night cycle of slightly more than 24 hours, so solar-...

10

The degree of orbital shadowing experienced by an orbiting object with small orbital altitude is determined by its beta angle (normally used in reference to LEO objects but the concept applies to lunar orbiters as well). The angle is taken between the satellite's orbital plane and the vector to the Sun. Depending on the value of the beta angle, a satellite ...

8

This may belong to Astronomy SE, but the $29.5$ Earth day figure, or more accurately the time in the third reference, is what you should be planning on when you or at least your instruments go to the Moon. This represents the actual cycle between daylight and darkness, the solar day. When one clicks on the references cited in the question, the first and ...

7

There is no circular orbit that has a share of 50:50 between night and day. The possible times are a bit less than 50% to 0% night or, respectively, a bit more than 50% day to 100% day. The two extreme cases are: an orbit that is aligned with the terminator (the border between night and day on the surface) is in perpetual daylight. an orbit that passes ...

7

Day length: As stated above, the moon has a night which lasts 14 days, while Mars has a day/night cycle of about 24 hours, 37 minutes. This has several implications. Power supply: although the Mars day is more similar to that of Earth, and solar power is more of an option, Mars is also further away, meaning the irradiance on the martian surface is less ...

5

It all depends on how you define "dayside" and "nightside", and how you define "entering" or "exiting" either one of them for a satellite. I suppose a big part of the confusion comes from this statement: Being in a polar orbit, Chandrayaan-2 enters the dayside of the Moon crossing the north pole, traverses through the dayside and enters the nightside ...

4

Spacecraft don't rot, nor do they rust (since there is not enough free oxygen anywhere but Earth), but they do degrade in various ways: The most obvious is that chemical and electrical equipment like batteries and on-board computers are severely degraded by the extreme cold and variations of temperature that happen. Electrical equipment is also damaged by ...

4

In air, on Earth, we can talk about the temperature of the air 2 meters above the surface. Of course if it's the top of your hat, then the temperature of that is affected both by the air temperature, and by the speed of the wind and how much sunlight is hitting it and other things like how much infrared your hat is radiating up into the sky. But 2 meters ...

4

Using the diameter 3476 km and the Moon solar day of 29.53 Earth days I calculated a speed of 15.4 km/h for the day night line at the Moon equator. $$\frac{3476 km*π} {29.53*24 h} = 15.4 km/h = 4.28 m/s$$ That is the necessary average speed at the lunar equator to stay in eternal day light. A rod is 5.0292 m, so a rod per moon-hour is 0.0473 mm/s A ...

3

A more generic answer could be: Angular speed (constant in any point on surface) is 2*pi radians every 29.53*24 hours, which gives 0.00443 rad/h. Linear speed depend on local distance from rotation axis, which is r * cos(latitude). Hence linear speed in any point on Moon surface is: v = 0.00443 * r * cos(lat) [rad/h]*[km] Of course for lat=0° it ...

3

Maybe not directly related to the question, anyway this site allows calculating "what time it is" in a specific location on the Moon: http://win98.altervista.org/space/exploration/moon/moontime.html In this page, the moon day duration (29.53 days) is divided into 24 moon-hours; when sunrise terminator reaches specified point, local time will be 06:00; when ...

3

Google Maps Moon likely uses a Simple Cylindrical projection for storing their map data. This is fine for the majority of the globe, but there are problems at the poles. Here are a few reasons why imagery of the poles is problematic: The data is prone to discontinuities because it has the entire top or bottom edge of the rectangular projection converging on ...

3

It was measured during the Apollo 14 mission. The Apollo Lunar Surface Experiments Package (ALSEP) placed on the lunar surface by the astronauts had a gas concentration sensor. During the last depressurization of the LM some oxygen was released. But the oxygen was gone in less than 3 minutes. So the oxygen left the landing spot on the lunar surface very ...

3

There is a lot in development to meet the 2024 Human Lunar return goal set by the National Space Council. At IAC this year, Blue Origin unveiled their national team consisting of themselves, Lockheed Martin, Northrop Grumman, and Draper Labs. This team will collaboratively build a Lunar Lander and submitted to NASA's design request on November 5th. Their ...

2

One question I really wanna ask; do spaceship's rot? Sort of, yes. In terms of "rotting", in the sense that a spacecraft will lose material or undergo degradation of its material components, then spacecraft do encounter this problem in the space environment for a variety of reasons. One big reason is atomic oxygen (that is, O, not O2), which is present in ...

2

Although this question has many answers already, I thought I'd add a more general answer How far could a human fall in a pressurised environment on various solar system bodies? I'm imagining that there are multi-story habitats on various bodies in the solar system, all pressurised to 1 atm. I'm also imagining that these habitats have a 'lift shaft' of ...

2

The strong distortions and star-like stripes are an artifact of Googles' image processing. For comparison, here is a screenshot of our own South Pole : I increased the contrast to make the artifacts more visible - the ice itself just has less contrast than the rocky features of the Moon.

2

The lighting is different at the poles. The sun is always very close to the horizon. There are some crater floors at the poles that never see sunlight. These crater floors are always inky black. Likewise there are polar plateaus and mountain tops that enjoy nearly constant sunlight. Shadows cast across these plateaus are always long though. And these long ...

1

An abstract for the "An Overview of the Volatiles Investigating Polar Exploration Rover (VIPER) Mission" talk, scheduled to be given in December at AGU, states VIPER is a solar and battery powered rover mission designed to operate over multiple lunar days, traversing several kilometers as it continuously monitors for subsurface hydrogen and other surface ...

1

I'm not aware of any measurements made more than a couple of meters from the surface, but with some assumptions to be described below, there should be no observable difference over the altitude range you mention. Ther are many factors that can influence a temperature measurement on an airless body. Yeah, yeah, some people talk about the moon's atmosphere. ...

1

Concern was not that the lunar dust will rise and cover the solar panels or instruments. The concern was as pointed out in the comments is that the dust particles rising up and hitting the lower bay of the lander and damaging or punching a hole. The simulation was done to study plume interaction with soil, the four plume cones when they interact with ground ...

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If you think about it, the Earth is at the same distance from the Moon that the Moon from the Earth (of course), so the Earth at the lunar surface should be 4 times bigger in appearence.

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