A permanently shadowed crater is a depression on a body in the

Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...

within which lies a point that is always in darkness. As of 2019, there are 324 known permanently shadowed regions on the Moon. Such regions also exist on Mercury and Ceres.

Location

Such a crater must be located at high

latitude In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...

(close to a pole) and be on a body with very small

axial tilt In astronomy, axial tilt, also known as obliquity, is the angle between an object's rotational axis and its orbital axis, which is the line perpendicular to its orbital plane; equivalently, it is the angle between its equatorial plane and orbita ...

. The Moon has an axial tilt of about 1.5°; Mercury, 0.03°;Planetary Fact Sheets
at http://nssdc.gsfc.nasa.gov and Ceres, about 4°. On the Moon, permanent shadow can exist at latitudes as low as 58°; approximately 50 permanently shadowed regions exist in the 58°- 65° latitude range for both lunar hemispheres. The cumulative area of permanently shadowed lunar regions is about 31 thousand km²; more than half of it is in the southern hemisphere.

Conditions inside craters

Craters of eternal darkness might be advantageous for

space exploration Space exploration is the process of utilizing astronomy and space technology to investigate outer space. While the exploration of space is currently carried out mainly by astronomers with telescopes, its physical exploration is conducted bo ...

and

colonization 475px, Map of the year each country achieved List of sovereign states by date of formation, independence. Colonization (British English: colonisation) is a process of establishing occupation of or control over foreign territories or peoples f ...

, as they preserve sources of water ice that can be converted into drinkable water, breathable oxygen, and rocket propellant. Several of such craters show indications of water ice in their interiors, including Rozhdestvenskiy and

Cabeus Cabeus is a lunar impact crater that is located about from the south pole of the Moon. At this location the crater is seen obliquely from Earth, and it is almost perpetually in deep shadow due to lack of sunlight. Hence, not much detail can be ...

craters on the Moon, and Juling Crater on Ceres. Other volatiles besides water can also be trapped in such craters, such as mercury. The

LCROSS The Lunar Crater Observation and Sensing Satellite (LCROSS) was a robotic spacecraft operated by NASA. The mission was conceived as a low-cost means of determining the nature of hydrogen detected at the polar regions of the Moon. Launched immedi ...

mission additionally found native

silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

and

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

in permanently shadowed craters on the Moon, probably brought there by electrostatic dust transport, and some inconclusive evidence for

platinum Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name origina ...

. Gold was estimated to have a soil mass abundance of 0.52% in these craters from LCROSS data, and mercury 0.39%. This high mercury abundance has been noted as a possible health hazard of water derived from permanently shadowed craters. The craters may also contain unusually high concentrations of

helium-3 Helium-3 (3He see also helion) is a light, stable isotope of helium with two protons and one neutron. (In contrast, the most common isotope, helium-4, has two protons and two neutrons.) Helium-3 and hydrogen-1 are the only stable nuclides with ...

. A business case analysis indicates that mining of propellants in the craters could become a profitable

commercial enterprise Business is the practice of making one's living or making money by producing or buying and selling products (such as goods and services). It is also "any activity or enterprise entered into for profit." A business entity is not necessari ...

. In some cases, peaks of eternal light are located nearby, that could be advantageous for solar power generation. For example, there are two peaks near

Shackleton Crater Shackleton is an impact crater that lies at the lunar south pole. The peaks along the crater's rim are exposed to almost continual sunlight, while the interior is permanently shadowed crater, perpetually in shadow. The low-temperature interior of ...

that are illuminated a combined ~94% of a lunar year. Permanently shadowed regions have a stable surface temperature. On the Moon, the temperature hovers somewhere at or below . Another temperatures estimate is . The low temperatures make the regions desirable locations for future infrared telescopes. For comparison: the boiling point of nitrogen at atmospheric pressure is . On the other hand, computer simulations show that powerful solar storms can charge up the soil in permanently shadowed regions near the lunar poles, and may possibly produce "sparks" that could vaporize and melt the soil. There are other unique challenges of such regions: dark environments that restrict the ability of rovers to perceive their surroundings, cryogenic regolith that could be hard to move on, and communication interruptions.

Planetary protection

In 2020, NASA assigned "sensitive location" status to the Moon's permanently shadowed regions to avoid their contamination. The

SETI Institute The SETI Institute is a not-for-profit research organization incorporated in 1984 whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to use this knowledge to inspire and guide present and futu ...

has a contract to manage

planetary protection Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions. Planetary protection refle ...

measures for NASA.

List

Below is an incomplete list of such craters: The Moon: * Shackleton *

Shoemaker Shoemaking is the process of making footwear. Originally, shoes were made one at a time by hand, often by groups of shoemakers, or '' cordwainers'' (sometimes misidentified as cobblers, who repair shoes rather than make them). In the 18th cen ...

* Erlanger *

Sylvester Sylvester or Silvester is a name derived from the Latin adjective ''silvestris'' meaning "wooded" or "wild", which derives from the noun ''silva'' meaning "woodland". Classical Latin spells this with ''i''. In Classical Latin, ''y'' represented a ...

* Rozhdestvenskiy * Malapert * Marston Mercury: * Chao Meng-Fu *

Kandinsky Wassily Wassilyevich Kandinsky ( – 13 December 1944) was a Russian painter and art theorist. Kandinsky is generally credited as one of the pioneers of abstract art, abstraction in western art. Born in Moscow, he spent his childhood in ...

* Petronius *

Prokofiev Sergei Sergeyevich Prokofiev; alternative transliterations of his name include ''Sergey'' or ''Serge'', and ''Prokofief'', ''Prokofieff'', or ''Prokofyev''. , group=n ( – 5 March 1953) was a Russian composer, pianist, and conductor who l ...

Tolkien John Ronald Reuel Tolkien (, 3 January 1892 – 2 September 1973) was an English writer and philologist. He was the author of the high fantasy works ''The Hobbit'' and ''The Lord of the Rings''. From 1925 to 1945, Tolkien was the Rawlinson ...

Ceres: * Juling

Research missions

Past

In 2009,

sent an impactor into a Cabeus crater, that resulted in detection of water in the ejected material. In 2012, The Lyman Alpha Mapping Project aboard NASA's

Lunar Reconnaissance Orbiter The Lunar Reconnaissance Orbiter (LRO) is a NASA robotic spacecraft currently orbiting the Moon in an eccentric Polar orbit, polar mapping orbit. Data collected by LRO have been described as essential for planning NASA's future human and robotic ...

has found that the permanently shadowed regions have a porous, powdery surface, that indicates the presence of water ice. In 2018, an analysis of the results of the

Moon Mineralogy Mapper The Moon Mineralogy Mapper (M3) is one of two instruments of NASA that was carried by India's first mission to the Moon, Chandrayaan-1, launched October 22, 2008. It is an imaging spectrometer, and the team is led by Principal investigator Carle ...

confirmed the existence of water ice deposits in permanently shadowed craters and crevices, with more abundance near the south pole. In 2022,

Lunar Flashlight Lunar Flashlight was a low-cost CubeSat lunar orbiter mission to explore, locate, and estimate size and composition of water ice deposits on the Moon for future exploitation by robots or humans. The spacecraft, of the 6U CubeSat format, ...

was launched as a secondary payload for the

Hakuto-R Mission 1 Hakuto-R Mission 1 was a failed private Japanese uncrewed lunar landing mission built and operated by ispace, which was launched in December 2022 for an attempted lunar landing in April 2023. This first Hakuto mission was primarily a technolog ...

mission. The cubesat mission failed to go into orbit around the moon when debris blocked propellant lines for the spacecraft’s thrusters. In 2025, the

IM-2 IM-2 was a lunar mission run by Intuitive Machines as part of NASA's Commercial Lunar Payload Services (CLPS) program. It was launched on 27 February 2025, at 00:16:30 UTC. The Nova-C lunar lander, named ''Athena'', reached the surface of t ...

lunar mission, conducted by

Intuitive Machines Intuitive Machines, Inc. is an American space exploration company headquartered in Houston, Texas. It was founded in 2013 by Stephen Altemus, Kam Ghaffarian, and Tim Crain, to provide commercial and government exploration of the Moon. Today the ...

for

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

's CLPS program, landed a

Nova-C The Intuitive Machines Nova-C, or simply Nova-C, is a class of lunar lander, lunar landers designed by Intuitive Machines (IM) to deliver small payloads to the surface of the Moon. Intuitive Machines was one of three service providers award ...

lunar lander. The lander carried a hopper named ''Grace'', a drone equipped with a

neutron spectrometer Neutron spectroscopy is a spectroscopic method of measuring atomic and magnetic motions by measuring the kinetic energy of emitted neutrons. The measured neutrons may be emitted directly (for example, by nuclear reactions), or they may scatter off ...

to explore the permanently shadowed region of the nearby Marston crater. The lander landed on its side and the hopper couldn't be deployed.

Current

A camera called ShadowCam has been built that is able to take high-resolution images of Permanently Shadowed Regions. It is a NASA instrument that flies on board the

Korea Pathfinder Lunar Orbiter The Korea Pathfinder Lunar Orbiter (KPLO), officially Danuri, is South Korea's first lunar mission. The orbiter, its science payload and ground control infrastructure are technology demonstrators. The orbiter will also be tasked with surveying ...

(KPLO) since 2022.

Planned

The proposed

International Lunar Observatory The International Lunar Observatory (ILO) is a private scientific and commercial lunar mission by the International Lunar Observatory Association (ILOA Hawai'i) of Kamuela, Hawaii to place a permanent observatory near the South Pole of the Moon t ...

mission involves a landing near the Malapert crater.

References

External links

Permanently Shadowed Regions Atlas

* {{Mercury (planet) Dynamics of the Solar System Articles containing video clips Surface features of the Moon Impact craters