What Were the First Lunar Landings?

The moment that the Apollo-11 mission touched down on the Moon, followed by Neil Armstrong‘s famous words – “That’s one small step for [a] man, one giant leap for mankind” – is one of the most iconic moments in history. The culmination of years of hard work and sacrifice, it was an achievement that forever established humanity as a space-faring species.

And in the year’s that followed, several more spacecraft and astronauts landed on the Moon. But before, during and after these missions, a number of other “lunar landings” were accomplished as well. Aside from astronauts, a number of robotic missions were mounted which were milestones in themselves. So exactly what were the earliest lunar landings?

Robotic Missions:

The first missions to the Moon consisted of probes and landers, the purpose of which was to study the lunar surface and determine where crewed missions might land. This took place during the 1950s where both the Soviet Space program and NASA sent landers to the Moon as part of their Luna and Pioneer programs.

The Soviet Luna 2 probe, the first man-made object to land on the Moon. Credit: NASA
The Soviet Luna 2 probe, the first man-made object to land on the Moon. Credit: NASA

After several attempts on both sides, the Soviets managed to achieve a successful lunar landing on Sept. 14th, 1959 with their Luna-2 spacecraft. After flying directly to the Moon for 36 hours, the spacecraft achieved a hard landing (i.e. crashed) on the surface west of the Mare Serenitatis – near the craters Aristides, Archimedes, and Autolycus.

The primary objective of the probe was to help confirm the discovery of the solar wind, turned up by the Luna-1 mission. However, with this crash landing, it became the first man-made object to touch down on the Moon. Upon impact, it scattered a series of Soviet emblems and ribbons that had been assembled into spheres, and which broke apart upon hitting the surface.

The next craft to make a lunar landing was the Soviet Luna-3 probe, almost a month after Luna-2 did. However, unlike its predecessor, the Luna-3 probe was equipped with a camera and managed to send back the first images of the far side of the Moon.

The first US spacecraft to impact the Moon was the Ranger-7 probe, which crashed into the Moon on July 31st, 1964. This came after a string of failures with previous spacecraft in the Pioneer and Ranger line of robotic spacecraft. Prior to impact, it too transmitted back photographs of the Lunar surface.

The Ranger 7 lander, which became the first US spacecraft to land on the Moon. Credit: NASA
The Ranger 7 lander, which became the first US spacecraft to land on the Moon. Credit: NASA

This was followed by the Ranger-8 lander, which impacted the surface of the Moon on Feb. 20th, 1965. The spacecraft took 7,000 high-resolution images of the Moon before crashing onto the surface, just 24 km from the Sea of Tranquility, which NASA had been surveying for the sake of their future Apollo missions. These images, which yielded details about the local terrain, helped to pave the way for crewed missions.

The first spacecraft to make a soft landing on the Moon was the Soviet Luna-9 mission, on February 3rd, 1966. This was accomplished through the use of an airbag system that allowed the probe to survive hitting the surface at a speed of 50 km/hour. It also became the first spacecraft to transmit photographic data back to Earth from the surface of another celestial body.

The first truly soft landing was made by the US with the Surveyor-1 spacecraft, which touched down on the surface of the Moon on June 2nd, 1966. After landing in the Ocean of Storms, the probe transmitted data back to Earth that would also prove useful for the eventual Apollo missions.

Several more Surveyor missions and one more Luna mission landed on the Moon before crewed mission began, as part of NASA’s Apollo program.

Launch of Apollo 11. On July 16, 1969, the huge, 363-feet tall Saturn V rocket launches on the Apollo 11 mission from Pad A, Launch Complex 39, Kennedy Space Center, at 9:32 a.m. EDT. Onboard the Apollo 11 spacecraft are astronauts Neil A. Armstrong, commander; Michael Collins, command module pilot; and Edwin E. Aldrin Jr., lunar module pilot. Apollo 11 was the United States' first lunar landing mission. While astronauts Armstrong and Aldrin descended in the Lunar Module "Eagle" to explore the Sea of Tranquility region of the moon, astronaut Collins remained with the Command and Service Modules "Columbia" in lunar orbit. Image credit: NASA
Launch of Apollo 11 mission aboard a Saturn V rocket on July 16th, 1969. Credit: NASA

Crewed Missions:

The first crewed landing on the Moon was none other than the historic Apollo-11 mission, which touched down on the lunar surface on July 20th, 1969. After achieving orbit around the Moon in their Command Module (aka. the Columbia module), Neil Armstrong and Buzz Aldrin rode the Lunar Excursion (Eagle) Module down to the surface of the Moon.

Once they had landed, Armstrong radioed to Mission Control and announced their arrival by saying: “Houston, Tranquility Base here. The Eagle has landed.” Once the crew had gone through their checklist and depressurized the cabin, the Eagles’ hatch was opened and Armstrong began walking down the ladder to the Lunar surface first.

When he reached the bottom of the ladder, Armstrong said: “I’m going to step off the LEM now” (referring to the Lunar Excursion Module). He then turned and set his left boot on the surface of the Moon at 2:56 UTC July 21st, 1969, and spoke the famous words “That’s one small step for [a] man, one giant leap for mankind.”

About 20 minutes after the first step, Aldrin joined Armstrong on the surface and became the second human to set foot on the Moon. The two then unveiled a plaque commemorating their flight, set up the Early Apollo Scientific Experiment Package, and planted the flag of the United States before blasting off in the Lunar Module.

Aldrin on the Moon. Astronaut Buzz Aldrin walks on the surface of the moon near the leg of the lunar module Eagle during the Apollo 11 mission. Mission commander Neil Armstrong took this photograph with a 70mm lunar surface camera. While astronauts Armstrong and Aldrin explored the Sea of Tranquility region of the moon, astronaut Michael Collins remained with the command and service modules in lunar orbit. Image Credit: NASA
Buzz Aldrin on the Moon during the Apollo 11 mission, with the reflection of Neil Armstrong visible in his face plate. Credit: NASA

Several more Apollo missions followed which expanded on the accomplishments of the Apollo-11 crew. The US and NASA would remain the only nation and space agency to successfully land astronauts on the Moon, an accomplishment that has not been matched to this day.

Today, multiple space agencies (and even private companies) are contemplating returning to the Moon. Between NASA, the European Space Agency (ESA), the Russian Space Agency (Roscosmos), and the Chinese National Space Administration (CNSA), there are several plans for crewed missions, and even the construction of permanent bases on the Moon.

We have written many great articles about the Moon here at Universe Today. Here’s Who Were the First Men on the Moon?, How Many People Have Walked on the Moon?, How Do We Know the Moon Landing Isn’t Fake?, Where Were You When Apollo 11 Landed on the Moon?, What Does The Apollo 11 Moon Landing Site Look Like Today?

Want more information about the Moon? Here’s NASA’s Lunar and Planetary Science page. And here’s NASA’s Solar System Exploration Guide.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Sources:

What is Lunar Regolith?

When you’re walking around on soft ground, do you notice how your feet leave impressions? Perhaps you’ve tracked some of the looser earth in your yard into the house on occasion? If you were to pick up some of these traces – what we refer to as dirt or soil – and examine them beneath a microscope, what would you see?

Essentially, you would be seeing the components of what is known as regolith, which is a collection of particles of dust, soil, broken rock, and other materials found here on Earth. But interestingly enough, this same basic material can be found in other terrestrial environments as well – including the Moon, Mars, other planets, and even asteroids.

Definition:

The term regolith refers to any layer of material covering solid rock, which can come in the form of dust, soil or broken rock. The word is derived from the combination of two Greek words – rhegos (which means “blanket”) and lithos (which means “rock).

Earth:

On Earth, regolith takes the form of dirt, soil, sand, and other components that are formed as a result of natural weathering and biological processes. Due to a combination of erosion, alluvial deposits (i.e. moving water deposing sand), volcanic eruptions, or tectonic activity, the material is slowly ground down and laid out over solid bedrock.

central Yilgarn Craton, Western Australia.
Picture of Mt Magnet in the Central Yilgarn Craton in Western Australia, which dates to the Precambrian Era. Credit: geomorphologie.revues.org

It can be made up of clays, silicates, various minerals, groundwater, and organic molecules. Regolith on Earth can vary from being essentially absent to being hundreds of meters thick. Its can also be very young (in the form of ash, alluvium, or lava rock that was just deposited) to hundreds of millions of years old (regolith dating to the Precambrian age occurs in parts of Australia).

On Earth, the presence of regolith is one of the important factors for most life, since few plants can grow on or within solid rock and animals would be unable to burrow or build shelter without loose material. Regolith is also important for human beings since it has been used since the dawn of civilization (in the form of mud bricks, concrete and ceramics) to build houses, roads, and other civil works.

The difference in terminology between “soil” (aka. dirt, mud, etc.) and “sand” is the presence of organic materials. In the former, it exists in abundance, and is what separates regolith on Earth from most other terrestrial environments in our Solar System.

The Moon:

The surface of the Moon is covered with a fine powdery material that scientists refer to it as “lunar regolith”. Nearly the entire lunar surface is covered with regolith, and bedrock is only visible on the walls of very steep craters.

Earth viewed from the Moon by the Apollo 11 spacecraft. Credit: NASA
Earth viewed from the Moon by the Apollo 11 spacecraft, across a sea of lunar soil. Credit: NASA

The Moon regolith was formed over billions of years by constant meteorite impacts on the surface of the Moon. Scientists estimate that the lunar regolith extends down 4-5 meters in some places, and even as deep as 15 meters in the older highland areas.

When the plans were put together for the Apollo missions, some scientists were concerned that the lunar regolith would be too light and powdery to support the weight of the lunar lander. Instead of landing on the surface, they were worried that the lander would just sink down into it like a snowbank.

However, landings performed by robotic Surveyor spacecraft showed that the lunar soil was firm enough to support a spacecraft, and astronauts later explained that the surface of the Moon felt very firm beneath their feet. During the Apollo landings, the astronauts often found it necessary to use a hammer to drive a core sampling tool into it.

Once astronauts reached the surface, they reported that the fine moon dust stuck to their spacesuits and then dusted the inside of the lunar lander. The astronauts also claimed that it got into their eyes, making them red; and worse, even got into their lungs, giving them coughs. Lunar dust is very abrasive, and has been noted for its ability to wear down spacesuits and electronics.

Alan Bean Takes Lunar Soil Sample
Alan Bean takes a sample of lunar regolith during the Apollo 12 mission. Credit: NASA

The reason for this is because lunar regolith is sharp and jagged. This is due to the fact that the Moon has no atmosphere or flowing water on it, and hence no natural weathering process. When the micro-meteoroids slammed into the surface and created all the particles, there was no process for wearing down its sharp edges.

The term lunar soil is often used interchangeably with “lunar regolith”, but some have argued that the term “soil” is not correct because it is defined as having organic content. However, standard usage among lunar scientists tends to ignore that distinction. “Lunar dust” is also used, but mainly to refer to even finer materials than lunar soil.

As NASA is working on plans to send humans back to the Moon in the coming years, researchers are working to learn the best ways to work with the lunar regolith. Future colonists could mine minerals, water, and even oxygen out of the lunar soil, and use it to manufacture bases with as well.

Mars:

Landers and rovers that have been sent to Mars by NASA, the Russians and the ESA have returned many interesting photographs, showing a landscape that is covered with vast expanses of sand and dust, as well as rocks and boulders.

A successful scoop of Martian regolith (NASA/JPL-Caltech/University of Arizona/Max Planck Institute)
A successful scoop of Martian regolith performed by NASA’s Phoenix lander. Credit: NASA/JPL-Caltech/University of Arizona/Max Planck Institute

Compared to lunar regolith, Mars dust is very fine and enough remains suspended in the atmosphere to give the sky a reddish hue. The dust is occasionally picked up in vast planet-wide dust storms, which are quite slow due to the very low density of the atmosphere.

The reason why Martian regolith is so much finer than that found on the Moon is attributed to the flowing water and river valleys that once covered its surface. Mars researchers are currently studying whether or not martian regolith is still being shaped in the present epoch as well.

It is believed that large quantities of water and carbon dioxide ices remain frozen within the regolith, which would be of use if and when manned missions (and even colonization efforts) take place in the coming decades.

Mars moon of Deimos is also covered by a layer of regolith that is estimated to be 50 meters (160 feet) thick. Images provided by the Viking 2 orbiter confirmed its presence from a height of 30 km (19 miles) above the moon’s surface.

Asteroids and Outer Solar System:

The only other planet in our Solar System that is known to have regolith is Titan, Saturn’s largest moon. The surface is known for its extensive fields of dunes, though the precise origin of them are not known. Some scientists have suggested that they may be small fragments of water ice eroded by Titan’s liquid methane, or possibly particulate organic matter that formed in Titan’s atmosphere and rained down on the surface.

Another possibility is that a series of powerful wind reversals, which occur twice during a single Saturn year (30 Earth years), are responsible for forming these dunes, which measure several hundred meters high and stretch across hundreds of kilometers.  Currently, Earth scientists are still not certain what Titan’s regolith is composed of.

Data returned by the Huygens Probe’s penetrometer indicated that the surface may be clay-like, but long-term analysis of the data has suggested that it may be composed of sand-like ice grains.  The images taken by the probe upon landing on the moon’s surface show a flat plain covered in rounded pebbles, which may be made of water ice, and suggest the action of moving fluids on them.

Asteroids have been observed to have regolith on their surfaces as well. These are the result of meteoriod impacts that have taken place over the course of millions of years, pulverizing their surfaces and creating dust and tiny particles that are carried within the craters.

False color picture of Eros' 5.3-kilometer (3.3-mile) surface crater, showing regolith inside. Credit: NASA/JPL/JHUAPL
False color picture taken by NASA’s NEAR Shoemaker camera of Eros’ 5.3-kilometer (3.3-mile) surface crater, showing the presence of regolith inside. Credit: NASA/JPL/JHUAPL

NASA’s NEAR Shoemaker spacecraft produced evidence of regolith on the surface of the asteroid 433 Eros, which remains the best images of asteroid regolith to date. Additional evidence has been provided by JAXA’s Hayabusa mission, which returned clear images of regolith on an asteroid that was thought to be too small to hold onto it.

Images provided by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras on board the Rosetta Spacecraft confirmed that the asteroid 21 Lutetia has a layer of regolith near its north pole, which was seen to flow in major landslides associated with variations in the asteriod’s albedo.

To break it down succinctly, wherever there is rock, there is likely to be regolith. Whether it is the product of wind or flowing water, or the presence of meteors impacting the surface, good old fashioned “dirt” can be found just about anywhere in our Solar System; and most likely, in the universe beyond…

We’ve done several articles about the Moon’s regolith here on Universe Today. Here’s a way astronauts might be able to extract water from lunar regolith with simple kitchen appliances, and an article about NASA’s search for a lunar digger.

Want to buy some lunar regolith simulant? Here’s a site that lets you buy it. Do you want to be a Moon miner? There’s lots of good metal in that lunar regolith.

You can listen to a very interesting podcast about the formation of the Moon from Astronomy Cast, Episode 17: Where Did the Moon Come From?

Reference:
NASA