Dawn at the Moon’s North Pole
Click for full image.
When dawn comes to the airless rough terrain of the Moon’s poles, it comes in fits and spurts. The floors of some craters never see it, while the high crater rims might have only a short time in darkness, their elevation high enough to keep the Sun above the horizon almost continuously. While there appear to be no places at the poles that have eternal daylight, there are places where night is short and infrequent.
The cool image to the right, cropped and reduced to post here, shows one such place close to the Moon’s north pole, the rim of Aepinus Crater. Taken by Lunar Reconnaissance Orbiter (LRO) on March 10, 2020, the illuminated area on this oblique image is about one by four miles in size. With dawn approaching this rim sees the Sun before the rest of the polar region, and remains illuminated long after the surrounding region has returned to darkness.
To get an idea of how small this one illuminated area is, below is a panorama showing the wide region around the rim.
The map to the right gives the location context of Aepinus Crater. In the panorama above, the pole is somewhere near the lower right corner. The crater itself sits between Hermite and Peary craters, both of which have shown evidence suggesting the presence of water ice in their permanently shadowed regions.
Thus, this rim on Aepinus Crater is prime real estate on the Moon. It will have extended periods of light, even during the lunar night, providing access to solar power energy. And it is likely close to those permanently shadowed crater floors, where ice is suspected to exist.
It is now dawn there. It is also one of the places where the dawn of the human settlement of the solar system will begin. Who will be first to land and take possession of this territory?
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Click for full image.
When dawn comes to the airless rough terrain of the Moon’s poles, it comes in fits and spurts. The floors of some craters never see it, while the high crater rims might have only a short time in darkness, their elevation high enough to keep the Sun above the horizon almost continuously. While there appear to be no places at the poles that have eternal daylight, there are places where night is short and infrequent.
The cool image to the right, cropped and reduced to post here, shows one such place close to the Moon’s north pole, the rim of Aepinus Crater. Taken by Lunar Reconnaissance Orbiter (LRO) on March 10, 2020, the illuminated area on this oblique image is about one by four miles in size. With dawn approaching this rim sees the Sun before the rest of the polar region, and remains illuminated long after the surrounding region has returned to darkness.
To get an idea of how small this one illuminated area is, below is a panorama showing the wide region around the rim.
The map to the right gives the location context of Aepinus Crater. In the panorama above, the pole is somewhere near the lower right corner. The crater itself sits between Hermite and Peary craters, both of which have shown evidence suggesting the presence of water ice in their permanently shadowed regions.
Thus, this rim on Aepinus Crater is prime real estate on the Moon. It will have extended periods of light, even during the lunar night, providing access to solar power energy. And it is likely close to those permanently shadowed crater floors, where ice is suspected to exist.
It is now dawn there. It is also one of the places where the dawn of the human settlement of the solar system will begin. Who will be first to land and take possession of this territory?
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
“Who will be first to land and take possession of this territory?”
Just above the large bright rock in the center of the picture is an X shaped building. Has someone else already claimed it?… 8-)
There is so much to discuss about the foolishness of trying to inhabit the poles of the Moon.
What is the ambient temperature in the sunlight? It is colder than the South Pole on Earth.
What is the solar azimuth and altitude? The altitude is very low, just barely above the horizon. The consequence is that a solar array would develop very little power. Normally, one angles the array to be normal to the direction of the sunlight. That would mean vertical in this instance.
Why is it that water is thought to be found at the bottom of the “deeply shadowed crater floors”? Because that is where the temperature is even colder, so cold that the enthalpy of the water is so low that any water vapor will not accelerate the molecules above the escape velocity of the Moon. If a molecule did get going that fast, it would escape out into space.
How would humans live in such an arid place without ample supplies of water? If you want to see the future, you should look at all the dessicated remains of dead climbers on Mount Everest.
If the water is at the bottom of the craters and the settlement is on the crest, who is going to play the role of Jack and Jill and go up the hill carrying their pails of water?
This place is not where night is “short and infrequent”. Most of the Moon has 15 days of “night”.
This place has 12-13 days worth of continuous darkness per year. But it does not happen once, from 0-13 days happens during this location’s Winter period.
From Mazarico’s, etal, “Illumination conditions of the lunar polar regions using LOLA topography”, Icarus 2011.
Also, the location of the north pole is not in the image. It is 56 km away and way beyond the right top of the panorama.
Also, you mention being “close” to PSRs. There are PSRs everywhere of various sizes. This particular location has a tiny site. But the nearest biggish one is 4.5 km away. Is this close? Not easy to run a power cable that far.
Mr Thompson considers it foolish to inhabit the lunar poles. As far as illuminated temperature, LRO Diviner shows the regolith temperature at the best illuminated spots as the South pole is from 217K (-56C) to 295K (22C). The mean average Earth south pole temperature is -50C.
He says “The altitude is very low, just barely above the horizon. The consequence is that a solar array would develop very little power. Normally, one angles the array to be normal to the direction of the sunlight. That would mean vertical in this instance.”
Uh, what we do is point the solar array at the Sun. Nicely, because the Sun is near about 0 degrees elevation thus a one axis solar array can slowly track the Sun as it travels around the horizon through the month. The azimuth goes from 0 to 360 deg every 30 days. Not very taxing to a solar array gimbal. Solar power is the best power per unit mass power generation method.
As to water, we need to get better data on where it is or how it is bound. Likely, PSRs are the best sites. Look at the PSR maps and you see some are near the highly illuminated sites. Why? The Sun is nearly parallel to the lunar surface thus a small crater will enable total blockage of the Sun all year round at highly illuminated sites. Yes, they are small. Otherwise it is a bit of a walk. Robots and rovers are required, not people to haul water. But likely we aren’t going to drink it or bottle it for sending back to Earth. Fuel and energy storage as the prime users.
Bruce Thompson,
Don’t worry too much about overcoming the problems at the poles. There are worse overall problems with just being on the Moon. People are smart. They are already working out solutions to these problems. As we gain experience, we will even find solutions to problems we don’t know about, yet. We always do.
It is one of the nice things about living with seven billion other people. Each of us only needs to find a small number of solutions to problems. The rest of the solutions come from everyone else, and that is how the free market economy works. We all get to sell our solutions to those who need them.
Half a century ago, we discovered that we can also solve new problems, such as going to other worlds.
Putting a base in the permanently shadowed crater has several benefits:
1. You are out the direct line of sight of the sun so you are better protected from solar flares/CME’s. That will cut down on the radiation exposure.
2. A crater floor/wall might always be in the shadow but the rim in permanent sunlight. So your solar arrays would never have a 15 day night.
3. Easier to stay warm then it is to stay cool.
>1. You are out the direct line of sight of the sun so you are better protected from solar flares/CME’s. That will cut down on the radiation exposure.
True. But at what cost? A base, astronaut suits would have to be designed for as low as 7K. About the temperature of liquid helium. Not a pleasant saunter.
>2. A crater floor/wall might always be in the shadow but the rim in permanent sunlight. So your solar arrays would never have a 15 day night.
No place on the Moon is in permanent sunlight. Even the crater rims at the south pole. You might luck out and get 6 months of sunlight, but more likely than not you will have >15 days of continuous darkness at the rim. Some few spots might have 3. Easier to stay warm then it is to stay cool.
What? Its easier to stay cold in the PSR. Good for storing liquid H2 and O2. Good for superconductors. Otherwise you need alot of heat to keep a person alive.