Challenged by President Kennedy, the Apollo program was designed to land humans on the Moon before the end of the decade. The program ran from the 1960’s through early 70’s with missions designed for landing men on the Moon. Before landing on the Moon, Apollo missions were carried out to study the lunar surface and gain experience in preparation of the actual landing on the Moon.
Apollo 11 was the first mission in which humans walked on the lunar surface and returned to Earth. It took the astronauts four days to arrive at the Moon. The spacecraft was comprised of two modules, the Command module and the Lunar Module. While approaching the landing site, the Lunar Module carrying two astronauts separated from the Command Module, which stayed in orbit.
Neil Armstrong became the first human to set foot on the Moon. "That's one small step for man, one giant leap for mankind" were the famous words he spoke out while stepping out of the spacecraft. During their stay on the Moon, the astronauts set up scientific experiments, took photographs, and collected lunar samples. Millions of people around the world watched the live broadcast on TV.
Apollo 13 was the seventh manned mission in the Apollo space program and the third intended to land on the Moon. The craft was launched on April 11, 1970, from the Kennedy Space Center, Florida. Two days later, the lunar landing was aborted after an oxygen tank exploded, crippling the service module upon which the Command Module depended. Despite a great technical and engineering challenge to survive, supported by NASA engineers on the ground, the crew returned safely to Earth on April 17. Several more Apollo missions were successfully carried out after Apollo 13.
The moon is not as small as it looks in space; it is roughly one-fourth the size of the Earth. The Moon is made up of multiple layers, from the surface, all the way to the inner core. The Moon may look like a big gray rock from the outside, but there is a diverse structure below the surface.
There is the surface at the top of the Moon, also called the “crust”. This is the part of the Moon that you can see at night, and you can see the Moon is light gray with areas of dark gray. The next level below the surface of the Moon is something called the “mantle”. It is a partially molten boundary layer with a radius of about 310 miles or 500 kilometers.
This whole “mantle” formed through the cooling of a global magma ocean right after the moon was formed 4.5 billion years ago. This mantle is mostly iron with a small amount of sulphur and other chemicals. Then at the center of the Moon is the outer core and the inner core. The moon has a solid iron inner core and a liquid outer core.
You might be wondering why some areas of the moon are lighter and some areas are darker. Well, many billion years ago, there were many volcanoes erupting that spilled lava all over the surface of the Moon, creating darker areas. Also, when giant meteors hit the surface of the Moon, that created giant craters too, which are darker. Pretty cool!
The surface of the moon is covered with rocks. Where did all of these rocks come from? After the moon was formed 4.5 billion years ago, it was a big ball of lava and magma that cooled down and solidified. Then there were volcanic eruptions that scattered rocks all over the surface. Also, lots of asteroids and comets crashed all over the surface, creating and scattering many more rocks all over the moon. This all took place over the course of billions of years.
So what are these rocks made of? Well, the rocks on the Moon are not too different from what you might find on the Earth. Moon rocks are called “volcanic” or “igneous” rocks, which are formed from lava and volcanoes. These types of rocks are made up of all sorts of minerals and chemicals, like silicon, iron, calcium, aluminum, and others. The natural color of the combination of minerals in theses rocks is a gray color. Some rocks also contain oxygen molecules! The oxygen can’t be extracted without a special scientific process.
How old are these rocks? Well, the rocks that were created billions of years ago are the same rocks on the Moon’s surface today! Scientists have determined that many of the rocks range from 1 to 4.5 billion years old.
What happened to the moon rocks brought down to Earth from the Apollo missions? Some of these rocks are owned by the government and the astronauts who got them. Some of them were given as gifts to nations around the world. But many of these moon rocks were distributed to museums that you can go to and see for yourself!
People have wondered for a long time about whether there is water on the Moon. Water in a liquid form cannot survive on the surface of the Moon, but what about ice? It is possible for ice to exist, but only in very specific places on the Moon. The ice is actually hidden in craters near the north and south poles! There are craters all over the Moon, but because the sun’s rays don’t get into the craters at the poles, the ice is safe.
In 1998, NASA’s Lunar Prospector mission detected the presence of hydrogen on the Moon as a sign of potential water. Why would hydrogen show that ice exists on the Moon? Because water is made up of hydrogen and oxygen! In 2009, the two parts of the NASA LCROSS mission intentionally crashed into one of those craters looking for water and ice. The first part sent up a big dust cloud and the second part of the craft flew down to analyze that dust cloud. This analysis proved that the ice exists.
But where did the ice come from? The ice on the moon could have come from comet impacts a long time ago. Comets are made of ice and rock and if they crash into the moon, that ice might remain in a crater. Or, the ice could have been made by oxygen molecules in the moon rocks and hydrogen from solar wind, combining to form ice. There may also be water and ice deep beneath the surface of the Moon.
So how could we use this ice? If people are ever going to survive on a lunar base in the future, they will need water to drink. And having a water source on the moon will be much more convenient than hauling water from Earth. Also, water can be split into hydrogen for rocket fuel, and oxygen for breathing! Pretty cool!
Let’s talk about two NASA missions that study the moon, the Lunar Reconnaissance Orbiter (LRO) and the Gravity Recovery and Interior Laboratory (GRAIL).
LRO currently orbits the Moon in a low polar orbit. This means the satellite is orbiting around the moon’s north and south poles and mapping the moon as it rotates. LRO will identify safe landing sites, find potential resources on the Moon, learn about the radiation environment, and demonstrate new technology.
GRAIL was designed to study the moon’s gravity and use that information to increase understanding of the Moon's history and what it’s like inside the Moon. Also, the gravity around the moon is not a perfect sphere. The gravity is “lumpy”, so when a satellite is in orbit around the moon, it needs to constantly make corrections to its orbit. GRAIL has properly mapped the moon’s gravity, and that information can be used to help future lunar missions!
Another reason the Moon’s gravity is so important is that it affects the Earth’s water levels. The gravity of the Moon pulls on the Earth’s water, and that’s why there’s a low and high tide at the ocean!
Missions like LRO and GRAIL are also important in staging for future exploration. We can use the information from these missions for future lunar bases and then use the Moon as a staging point to explore Mars and the solar system!