About our Moon and the
Lunar Reconnaissance Orbiter Mission
What is the LRO?
The Lunar Reconnaissance Orbiter, or LRO, is a robotic mission that will study the Moon during its orbit. The LRO is scheduled to be launched in 2008 from Kennedy Space Center. Its primary mission is to spend one year in a polar orbit collecting detailed information about the Moon’s environment. This information will help humans return safely to the Moon where they can prepare for a human mission to Mars — and beyond!
The orbiter will have solar arrays and a Lithium-Ion battery for power. It will have a computer and use radio to receive commands and send information back to Earth. It has six main instruments: CRaTER, DIVINER, LAMP, LOLA, LEND, and LROC.
What will LRO instruments tell scientists?
CRaTER - Cosmic Ray Telescope for the Effects of Radiation - will study the amount and types of radiation that the Moon receives, and test the protection offered by different types of shielding for future bases.
Diviner (actually Diviner Lunar Radometer Experiment) will map out the daytime and nighttime temperatures on the surface of the Moon, and will help scientists find frozen water on the Moon’s surface and near-surface.
LAMP - Lyman Alpha Mapping Project - will measure ultraviolet light from star-shine that is reflected off the lunar surface. This tiny amount of reflected light will help scientists create maps of areas that cannot be seen — like permanently shadowed regions. LAMP is a bit like using night-vision goggles. In addition to mapping out these shadowed regions, LAMP will also help to identify frozen water in permanently shadowed areas because ice reflects ultraviolet light a bit differently from rock.
LOLA - Lunar Orbiter Laser Altimeter - will use a laser to create a high-resolution topographical map of the Moon.
LEND - Lunar Exploration Neutron Detector - will map the amounts of hydrogen in the top two meters of the Moon’s surface; this will help scientists locate the position and the amount of frozen water on the Moon’s surface.
LROC - Lunar Reconnaissance Orbiter Camera - will take high-resolution pictures of the Moon, helping scientists and engineers identify future landing hazards, which areas of the Moon are permanently in shadow or permanently in sunlight, and where certain minerals exist — ilmenite — that can be heated to release oxygen.
Together, these instruments will help us learn more about the lunar environment. They will help us find safe locations to land and to build future human colonies and they will tell us where we can find water and other valuable resources on the Moon.
Don’t we already know enough about the Moon?
Based on earlier lunar missions, including the valuable visits by the Apollo astronauts, we have an understanding of the structure of the Moon’s interior, types of rocks found on the lunar surface, the events that have shaped the Moon, and the conditions that exist at the surface. But we will need to know much more about the challenges of its environment and its resources before we can send people to live and work on the Moon for long periods of time. The Apollo missions visited only 6 sites; imagine describing the whole Earth if you had only visited 6 places for a few days at each stop … you would be missing a lot of information! Russia sent three robotic missions that returned samples, so we know about the materials at nine sites. Still, that’s a whole lot of the Moon that is unexplored!
Orbiters have helped to add more detail to the picture. The Lunar Prospector and Clementine missions provided scientists with detailed information about the surface features and composition about much of the Moon’s surface. The instruments on those missions were the very best, and they returned some exciting new data — particularly evidence for ice at shadowed regions at the poles. But our instruments have gotten even better. The cameras and detectors aboard the LRO will use new and refined technology be able to provide information that is much more detailed than what was collected by earlier missions.
by Pat Rawlings; copyright: NASA.
Before we send people to the Moon, we need to have a very strong understanding of the conditions they will face when they are working on the surface for weeks at a time. The LRO instruments will help us characterize the temperatures on the lunar surface and how the temperatures change from day to night (DIVINER). CRaTER will help us characterize radiation levels reaching the lunar surface and will also test shielding to see if it will protect people working on the surface. We do not have detailed knowledge of the topography of the Moon. Right now, we can identify objects that are about 50 meters (about 165 feet) across for most of the Moon – the resolution is better in a limited number of places. With LOLA and LROC, we will finally have information that allows us to map the surface to within a half a meter (1.5 feet)! This is vital to determining safe landing sites and making maps to help astronauts navigate across the surface.
Future human colonies can mine the Moon for resources, such as oxygen, water, fuel, and building materials — but they will need to know where these resources are in more detail than we understand now. Based on earlier missions, we know that the rocks and soil contain aluminum, iron, silica, titanium and other elements that can be used in buildings and solar panels. The loose lunar regolith can be used to make “lunar bricks” for building structures. The LROC and LEND instruments will help us map the presence of different elements and characterize the regolith.
Location of iron-rich rocks on the Moon, based on information from the
Clementine mission instruments. Areas with increased iron tend to be in
the lowlands — the basalt filled impact basins.
Location of titanium-rich rocks on the Moon, based on information from the
Clementine mission instruments. Areas with increased titanium tend to be in
the lowlands — the basalt filled impact basins.
Scientists have evidence from previous missions that water ice may exist on the Moon’s surface in some of the permanently shadowed regions; we need to confirm its presence. If water ice exists it can be used for water and can be broken into its parts — oxygen and hydrogen for air and fuel. LAMP, LOLA, LEND, and even DIVINER will provide valuable information to identify and map water ice on the Moon.
Why do we expect water to be on the Moon?
Comets made out of water ice and other materials have hit the Moon throughout its history. If the comet has struck in an area that does not receive much sunlight, like the south polar region of the Moon, that ice may still be there. Earlier missions to the Moon — Clementine and Lunar Prospector — provided evidence for the presence of water ice. The Lunar Prospector spacecraft detected large amounts of hydrogen in the polar regions, which scientists interpret to be coming from water ice. According to these data, frozen soil and ice at the poles may contain as much as 1–10 billion tons of water locked into deeply shaded craters. That is an amount equal to what is consumed by U.S. cities in 10 days. It would be enough to supply the population of a lunar base for a long time. In addition to sustaining life in a colony, water can be used for rocket fuel and for air by breaking it into its separate chemicals of hydrogen and oxygen.
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Clementine image of the Moon’s south pole showing where scientists believe water is present. |
Why are we going to the Moon if we really want to go to Mars?
Building a human presence on the Moon will allow us to develop and test some of the technology that will be needed to send a human mission to Mars — and beyond! The Moon is closer and therefore more cost-effective to visit. In unexpected situations, critical materials can be sent to the Moon in a few days compared to the months it takes to send something to Mars. By establishing a base on the Moon, we will learn what we need to be prepared for living and working on Mars.
Also it will be easier to launch rockets filled with necessary resources to Mars from the Moon’s lower gravity than from Earth.
Finally, a Moon base will allow us to learn much more about Earth’s nearest neighbor, and provide a stable airless environment for studying the Universe.
What is our Moon like?
Our Moon has relatively young dark smooth lowlands (mare), and ancient light rough highlands (terrae). The highlands are covered with craters from asteroid and comet impacts; there are fewer craters on the younger lowlands.
The surface is covered with dusty rock material called regolith — in some cases deeper than 15 meters (50 feet). Regolith is rock that has been pulverized by the impacts.
The Moon has no atmosphere, so there is no wind and the sky is dark — like the Earth’s sky on a clear night. There are extreme temperatures: 130°C (265°F) during the day and –155°C (–250°F) at night. There is no flowing water at the surface of the Moon; any existent water is frozen in the areas that are permanently shadowed; these are the only areas not exposed to the Sun’s heat during part of the lunar day.
Space is filled with radiation, primarily from our Sun; this radiation is deadly to humans unless they are protected from it. While Earth’s magnetic field offers us protection from incoming solar radiation, the Moon has virtually no magnetic field and so the radiation levels are very high.
Because it is less dense and smaller than Earth, the Moon has less gravity. The surface gravity is 1/6 Earth’s gravity. Our Moon is tilted on its axis only a tiny amount, so there essentially are no seasons. The Moon orbits Earth once every 27 days — and turns on its axis once every 27 days. This means that the lunar “day” is equal to a lunar “year.” It also means that the near side faces Earth constantly. Astronauts would experience daylight for almost two Earth weeks and then darkness for the same time.
How did the Moon form?
Most scientists now believe that about 4.5 billion years ago — shortly after the planets in our solar system formed — a planetary body the size of Mars collided with Earth. The impactor broke apart and pieces of the impactor and Earth’s outer layers were blown out into orbit around Earth. Over a short time — perhaps a hundred years or less, these pieces collided and stuck together — accreted — to form our Moon.
The heat from accretion caused the Moon, or at least its outer layer, to melt, creating a magma ocean. Eventually the crust cooled. For the first 600 million years of its existence, large asteroids continued to strike the Moon and the planets in our solar system, creating the large basins and craters we see on the Moon. After about 3.9 billion years, much of the “debris” in the solar system had been swept up into the planets and their moons, and impact strikes were smaller and less frequent.
While cool on the outside, the interior was still hot. Molten rock would still rise to the Moon’s surface and break through cracks or erupt at volcanos. The lava filled the basin and crater floors — the low areas on the Moon. It cooled quickly, forming fine-grained dark, volcanic rocks called basalt; basalt is the most common type of volcanic rock we find Earth. When you look at the Moon, you can see the large, somewhat circular, dark basins. These are the basalt-filled ancient impact basins. In spite of this exciting beginning and history, the Moon has been geologically inactive for at least the last billion years.
What will it be like to live and work on the Moon?
If humans are to live on the Moon, even for brief periods, they will need a wide range of support systems. They'll need a place to work, rest, and live that protects them from the cold and dangerous radiation of the space environment. They will need power, light, air, food, water, and heat. They'll need robust transportation and equipment able to operate in low temperatures and the hostile environment of space. They will need to be able to communicate with Earth, other colonies, and shuttles.
Image by Pat Rawlings; copyright: NASA.
They will also need to deal with health issues. Reduced gravity is a challenge to people living on the Moon with one-sixth Earth's gravity. Under reduced gravity conditions, there is less “load” on bones and muscles, so living organisms lose bone mass, muscle tissue, and fluids. Even the heart — a muscle — loses mass because it does not have to work as hard. Humans on the Moon must exercise to maintain their bone and tissue mass so that they can return to Earth's gravity and function well. More research is needed to understand the effects of reduced gravity on the human body — and how to counter these effects.
Any habitat would have to provide shelter from the extreme temperatures and from incoming radiation. Moon bases may include subsurface buildings to increase protection from radiation and micrometeorites.
There probably would be three basic types of modules: habitation, laboratory, and support modules. The habitat would have sleeping quarters, a kitchen (or galley), and bathroom facilities. Windows would have to be small and made of multiple thick glass sheets to block cosmic radiation. Laboratory modules would be used for conducting experiments. A colony would also need several types of support modules and facilities, including a greenhouse to grow food; a power plant — either solar or nuclear; a place to store construction equipment and do maintenance; a central control, life support, and communications center; resource utilization facilities for processing mined materials; and a landing/launch pad. Accidents or fires could occur or meteorites might strike the base. If an accident occurs in a large structure, it might be necessary to abandon the entire building. However, in a module system, a damaged module could simply be isolated from the rest by closing the hatches shared with other modules, similar to the plan currently onboard the International Space Station. The colonists will need some type of evacuation strategy, such as emergency escape transportation in the event of a severe accident.
by Pat Rawlings; copyright: NASA.
The colony team would initially include scientists and engineers. These individuals would probably have many other capabilities, such as medical training and construction training. As the colony grew, other personnel would need to be added. They would conduct research and experiments in the laboratories, work on colony construction, maintain the base, and mine resources. Medical specialists, cooks, safety specialists, administrative staff, and cleaning crews would be needed to support the efforts. These crews would be replaced on a regular basis in the same way as teams who work at Antarctic bases on Earth.
Image by Pat Rawlings; copyright: NASA.
How will LRO help us determine where to explore in the future?
The Lunar Reconnaissance Orbiter will help us identify the most promising locations for mining for water and for minerals and will provide valuable detailed data about the lunar environment. The areas of potential occupation need to be easily reached (the terrain needs to be somewhat smooth). The temperatures need to be in a range that can be controlled by our technology so that humans or robotic missions can operate. If humans are involved, radiation will have to be blocked by shielding either through a natural setting (for example under thick lunar regolith or in lava tubes beneath the surface) or through buildings and spacesuits. The LRO will help us identify locations that are a balance between meeting these needs, accessing resources, and undertaking science and engineering experiments.
When will humans be back on the Moon?
NASA plans to have humans on the Moon possibly by about 2020. That means that today’s 10 year old child will be 25 — and may be helping NASA build and operate a new Moon base as a geologist, resource manager, engineer, emergency medical technician, lab technician, safety officer, pilot, mechanic, or chef. All of these people — and others — will be needed to make our future Moon Base operate smoothly!
