The Future for the Moon

www.moonlandings.co.uk

Why is the Moon Important to us?

Because it is a partner of the Earth

Fundamentally linked to the origin of the Earth

Earth-Moon pair an extraordinary double planet

Possible formation by giant meteorite impact on primordial Earth

A Museum of Planetary History

Preserved records of planetary formation, & early history

Period of intense meteorite bombardment from formation of solar system (4.5 billion years) to about 4.0 billion years ago

Early widespread melting, formation of outer 'magma ocean', chemical separations; traces still preserved in rocks

Widespread basaltic volcanic eruptions: a common planetary process

Information no longer accessible on active planets (Earth, Venus, Mars)

Only other terrestrial planet with absolutely calibrated geological history (from ages measured on returned samples)

Standard for measuring surface ages by crater counts on all other planets and moons (Mercury to Neptune)

Preserved records of large-body impact flux in Earth-Moon system over geologic time

Easily accessible field laboratory for fundamental planetary processes

Meteorite impact phenomena: mechanics of large and small crater formation; impact-produced rocks

Development of surface regolith on airless planet; relevant to studies of Mercury, asteroids, other bodies

Crustal formation, melting, and volcanism

A Space Probe and Time Machine

Direct atomic samples from Sun (solar wind, solar flares)

Rocks and soil contain historical records of solar behaviour over millions to billions of years

Evidence for historical variations in solar wind

Historical data on cosmic-ray activities, flux levels

Historical records of impact flux rates, especially for small and dust-sized particles

A Place to support Human Life

Most accessible planet for future human activity

Candidate for permanent human presence

Scientific base potential: lunar/planetary science, astronomy, other sciences

Resource potential (oxygen, metals, volatiles) support future human space activity beyond Moon

What did we learn from the Apollo Programme?

Not primordial it is an evolved terrestrial planet

Ancient it still preserves an early history (the first billion years), which must be common to all terrestrial planets

Shows evidence for wholesale primordial melting, formation of outer 'magma ocean'large-scale chemical separations within Moon; traces still remain in lunar rocks

Dark lunar maria ('seas') and light-colored highlands made of chemically and mineralogically different rocks

Maria made of dark volcanic lavas (basalts) poured out in huge volcanic eruptions 3-4 billion years ago

Lifeless - no life, no fossils, no organic chemicals

Chemically similar to Earth, but significantly different in details: It has no indigenous water, is poor in volatile elements (See 'Water on the Moon?')

Preserves effects of catastrophic early meteorite bombardment - common to all terrestrial planets, including Earth, but traces no longer preserved on active planets like Earth

Not uniform throughout; is divided (like Earth) into outer crust, inner mantle, and possibly a small metal core

Globally asymmetric (slightly egg-shaped); thicker crust on farside, most maria deposits (lava flows) on nearside.

Has no magnetic field, little or no metallic core like Earth's, but 'fossil' magnetism is preserved in lunar rocks

Large-scale (100 - 1000 kilometres) magnetic anomalies preserved on lunar surface

Lunar surface covered by powdery fragmental layer ('lunar soil' or regolith), produced by shattering of bedrock by prolonged meteorite bombardment

History of Sun and cosmic rays determined from actual atoms of Sun and stars trapped in lunar rocks and soil

Unexplained nitrogen anomalies detected in ancient solar wind trapped in lunar regolith

Pre-Apollo hypotheses about lunar origins shown to be inadequate. Scientists now believe that the Moon formed as a result of a collision between the early Earth and a former, smaller planet about 4.6 billion years ago. The giant impact sprayed vaporised material into a disk that orbited the Earth: this vapour later cooled into droplets that coagulated into the Moon

What did we learn from the Clementine and Lunar Prospector?

Work to understand the data returned from two recent unmanned missions (Clementine 1994; Lunar Prospector 1998) is ongoing. However, we do have new knowledge about the Moon and some first-order conclusions from these two missions:

The Global Surface Composition of the Moon

Crust is highly enriched in aluminium on a global basis, supporting its origin by early global melting (the magma ocean)

Incompatible trace elements (i.e., those that do not go easily into rock-forming minerals) are concentrated within an elliptical zone on the western nearside (the Imbrium-Procellarum region)

Mafic (i.e., magnesium and iron-rich) zones are found within the lunar highlands, usually associated with large impact basins

Mare basalts rich in titanium (returned in abundance by the Apollo 11 and 17 missions) are rare in the global mare lava inventory

The Topography of the Moon

The Moon displays an enormous range of global relief (16 kilometres), as big a range as the more active and diverse Earth

The dominant cause of high relief on the Moon is the presence of large, multi-ring impact basins

Lunar multi-ring basins appear to preserve their original topography for most of geological time

The South Pole-Aitken Basin on the farside of the Moon is the largest (2600 kilometres diameter) and deepest (over 12 kilometres) impact basin known in the solar system

The Internal Structure of the Moon

The Moon shows many areas of excess subsurface mass (mascons) that cause the gravity field of the Moon to be very lumpy', requiring constant adjustments for orbiting spacecraft

The mascons are always found beneath the floors of large impact basins and probably represent plugs of dense, uplifted rocks from the lunar mantle

The Poles of the Moon

Areas are found near the lunar poles that are in permanent darkness; some areas may be in permanent sunlight

The south pole appears to have more dark area than the north pole, mostly as a result of its location just inside the rim crest of South Pole-Aitken Basin

Water ice, derived from impacting comets, is found in the dark areas near both poles (See 'Water on the Moon?')

What Do We Do Now?

For all we have learned about the Moon, the exploration of our nearest neighbour world has only just begun. Much of the returned lunar sample material remains to be studied, and we will continue to analyze the data from the instruments on the Moon as long as they operate.

From what we have learned, we can now confidently plan ways to use the Moon to help us understand better the behaviour of our own planet. One such project involves using several reflectors that were placed on the Moon by Apollo astronauts. By bouncing a laser beam off these reflectors and back to Earth, we can measure variations in the Earth-Moon distance (about 400,000 kilometres) with an accuracy of a few centimetres, or one part in 10 billion. Continued measurement of the Earth-Moon distance as the Moon moves in its orbit around us will make it possible to recognise tiny variations that exist in the Moon's motions. These variations occur because the Moon is not quite a uniform sphere, and these minor movements contain important clues about what the inside of the Moon is like.

The laser reflectors, which need no power, will last on the Moon for more than a century before being covered with slow-moving lunar dust and falling meteorites. Long before that, continuous measurements should make it possible to understand the internal structure of the Moon. It may even be possible to use the Moon to measure the slow movements of Earth's continents and oceans as they converge and separate.

To further explore the Moon itself, we can continue to send machines in place of humans. Unmanned spacecraft could encircle the Moon from pole to pole, measuring its chemical composition, radioactivity, gravity and magnetism. Missions would carry on the tasks begun by the Apollo Programme and would produce physical and chemical maps of the whole Moon. Such an orbiter could also serve as a prototype for later spacecraft and instruments to be put into orbit around Mars or Mercury to map and study those planets as we have mapped and explored the Moon.

Other spacecraft, like the Russian Luna landers, could return small samples from locations never before visited: the far side, the poles, or the sites of the puzzling transient events. Because of the Apollo Programme, we now know how to analyze such small samples and how to interpret correctly the data we obtain. Each landing and sample return would have a double purpose: to teach us more about the Moon, and help us design the machines that might return samples from the surfaces of Mars, Mercury, or the moons of Jupiter.

Finally, we may see humans return to the Moon, not as passing visitors but as long-term residents, building bases from which to explore the Moon and erecting astronomical instruments that use the Moon as a platform from which to see deeper into the mysterious universe that surrounds us.

Why haven't there been more lunar landings in recent years?

The last manned lunar landing took place in December 1972 with Apollo 17. Despite the public's interest in the first lunar landing in 1969, NASA's budget was cut in 1971 to the lowest level in nine years. Because of this budget cut, Apollo 18, 19 and 20 were cancelled.

A Newsweek poll taken only months after the first lunar landing in October 1969, showed that 56% of Americans thought the government should be spending less money on space exploration, and only 10% thought the government should be spending more money. There was no longer public recognition of the benefits of space (or lunar) exploration. US President Nixon, his administration, Congress and the press soon followed in showing disinterest for the space programme.

Exploration of the Moon could no longer hold Americans' attention. There were just too many things happening closer to home. The years of Apollo were also the years of demonstration for the civil rights movement, the years of political unrest with Martin Luther King and Robert Kennedy being slain, along with thousands of Americans in Vietnam.

If water is eventually found to be feasibly extractable, then this factor alone might make the whole idea of travelling to the Moon and using its resources again more appealling.


	www.moonlandings.co.uk Moon Gravity \| Far Side \| Static Moon \| Earth Facts \| Top Ten Scientific Discoveries \| Spinoffs \| Landing Sites \| The Future for the Moon \| Water on the Moon? \| Detailed Moon Statistics The Future for the Moon Why is the Moon Important to us? Because it is a partner of the Earth Fundamentally linked to the origin of the Earth Earth-Moon pair an extraordinary double planet Possible formation by giant meteorite impact on primordial Earth A Museum of Planetary History Preserved records of planetary formation, & early history Period of intense meteorite bombardment from formation of solar system (4.5 billion years) to about 4.0 billion years ago Early widespread melting, formation of outer 'magma ocean', chemical separations; traces still preserved in rocks Widespread basaltic volcanic eruptions: a common planetary process Information no longer accessible on active planets (Earth, Venus, Mars) Only other terrestrial planet with absolutely calibrated geological history (from ages measured on returned samples) Standard for measuring surface ages by crater counts on all other planets and moons (Mercury to Neptune) Preserved records of large-body impact flux in Earth-Moon system over geologic time Easily accessible field laboratory for fundamental planetary processes Meteorite impact phenomena: mechanics of large and small crater formation; impact-produced rocks Development of surface regolith on airless planet; relevant to studies of Mercury, asteroids, other bodies Crustal formation, melting, and volcanism A Space Probe and Time Machine Direct atomic samples from Sun (solar wind, solar flares) Rocks and soil contain historical records of solar behaviour over millions to billions of years Evidence for historical variations in solar wind Historical data on cosmic-ray activities, flux levels Historical records of impact flux rates, especially for small and dust-sized particles A Place to support Human Life Most accessible planet for future human activity Candidate for permanent human presence Scientific base potential: lunar/planetary science, astronomy, other sciences Resource potential (oxygen, metals, volatiles) support future human space activity beyond Moon What did we learn from the Apollo Programme? Not primordial it is an evolved terrestrial planet Ancient it still preserves an early history (the first billion years), which must be common to all terrestrial planets Shows evidence for wholesale primordial melting, formation of outer 'magma ocean'large-scale chemical separations within Moon; traces still remain in lunar rocks Dark lunar maria ('seas') and light-colored highlands made of chemically and mineralogically different rocks Maria made of dark volcanic lavas (basalts) poured out in huge volcanic eruptions 3-4 billion years ago Lifeless - no life, no fossils, no organic chemicals Chemically similar to Earth, but significantly different in details: It has no indigenous water, is poor in volatile elements (See 'Water on the Moon?') Preserves effects of catastrophic early meteorite bombardment - common to all terrestrial planets, including Earth, but traces no longer preserved on active planets like Earth Not uniform throughout; is divided (like Earth) into outer crust, inner mantle, and possibly a small metal core Globally asymmetric (slightly egg-shaped); thicker crust on farside, most maria deposits (lava flows) on nearside. Has no magnetic field, little or no metallic core like Earth's, but 'fossil' magnetism is preserved in lunar rocks Large-scale (100 - 1000 kilometres) magnetic anomalies preserved on lunar surface Lunar surface covered by powdery fragmental layer ('lunar soil' or regolith), produced by shattering of bedrock by prolonged meteorite bombardment History of Sun and cosmic rays determined from actual atoms of Sun and stars trapped in lunar rocks and soil Unexplained nitrogen anomalies detected in ancient solar wind trapped in lunar regolith Pre-Apollo hypotheses about lunar origins shown to be inadequate. Scientists now believe that the Moon formed as a result of a collision between the early Earth and a former, smaller planet about 4.6 billion years ago. The giant impact sprayed vaporised material into a disk that orbited the Earth: this vapour later cooled into droplets that coagulated into the Moon What did we learn from the Clementine and Lunar Prospector? Work to understand the data returned from two recent unmanned missions (Clementine 1994; Lunar Prospector 1998) is ongoing. However, we do have new knowledge about the Moon and some first-order conclusions from these two missions: The Global Surface Composition of the Moon Crust is highly enriched in aluminium on a global basis, supporting its origin by early global melting (the magma ocean) Incompatible trace elements (i.e., those that do not go easily into rock-forming minerals) are concentrated within an elliptical zone on the western nearside (the Imbrium-Procellarum region) Mafic (i.e., magnesium and iron-rich) zones are found within the lunar highlands, usually associated with large impact basins Mare basalts rich in titanium (returned in abundance by the Apollo 11 and 17 missions) are rare in the global mare lava inventory The Topography of the Moon The Moon displays an enormous range of global relief (16 kilometres), as big a range as the more active and diverse Earth The dominant cause of high relief on the Moon is the presence of large, multi-ring impact basins Lunar multi-ring basins appear to preserve their original topography for most of geological time The South Pole-Aitken Basin on the farside of the Moon is the largest (2600 kilometres diameter) and deepest (over 12 kilometres) impact basin known in the solar system The Internal Structure of the Moon The Moon shows many areas of excess subsurface mass (mascons) that cause the gravity field of the Moon to be very lumpy', requiring constant adjustments for orbiting spacecraft The mascons are always found beneath the floors of large impact basins and probably represent plugs of dense, uplifted rocks from the lunar mantle The Poles of the Moon Areas are found near the lunar poles that are in permanent darkness; some areas may be in permanent sunlight The south pole appears to have more dark area than the north pole, mostly as a result of its location just inside the rim crest of South Pole-Aitken Basin Water ice, derived from impacting comets, is found in the dark areas near both poles (See 'Water on the Moon?') What Do We Do Now? For all we have learned about the Moon, the exploration of our nearest neighbour world has only just begun. Much of the returned lunar sample material remains to be studied, and we will continue to analyze the data from the instruments on the Moon as long as they operate. From what we have learned, we can now confidently plan ways to use the Moon to help us understand better the behaviour of our own planet. One such project involves using several reflectors that were placed on the Moon by Apollo astronauts. By bouncing a laser beam off these reflectors and back to Earth, we can measure variations in the Earth-Moon distance (about 400,000 kilometres) with an accuracy of a few centimetres, or one part in 10 billion. Continued measurement of the Earth-Moon distance as the Moon moves in its orbit around us will make it possible to recognise tiny variations that exist in the Moon's motions. These variations occur because the Moon is not quite a uniform sphere, and these minor movements contain important clues about what the inside of the Moon is like. The laser reflectors, which need no power, will last on the Moon for more than a century before being covered with slow-moving lunar dust and falling meteorites. Long before that, continuous measurements should make it possible to understand the internal structure of the Moon. It may even be possible to use the Moon to measure the slow movements of Earth's continents and oceans as they converge and separate. To further explore the Moon itself, we can continue to send machines in place of humans. Unmanned spacecraft could encircle the Moon from pole to pole, measuring its chemical composition, radioactivity, gravity and magnetism. Missions would carry on the tasks begun by the Apollo Programme and would produce physical and chemical maps of the whole Moon. Such an orbiter could also serve as a prototype for later spacecraft and instruments to be put into orbit around Mars or Mercury to map and study those planets as we have mapped and explored the Moon. Other spacecraft, like the Russian Luna landers, could return small samples from locations never before visited: the far side, the poles, or the sites of the puzzling transient events. Because of the Apollo Programme, we now know how to analyze such small samples and how to interpret correctly the data we obtain. Each landing and sample return would have a double purpose: to teach us more about the Moon, and help us design the machines that might return samples from the surfaces of Mars, Mercury, or the moons of Jupiter. Finally, we may see humans return to the Moon, not as passing visitors but as long-term residents, building bases from which to explore the Moon and erecting astronomical instruments that use the Moon as a platform from which to see deeper into the mysterious universe that surrounds us. Why haven't there been more lunar landings in recent years? The last manned lunar landing took place in December 1972 with Apollo 17. Despite the public's interest in the first lunar landing in 1969, NASA's budget was cut in 1971 to the lowest level in nine years. Because of this budget cut, Apollo 18, 19 and 20 were cancelled. A Newsweek poll taken only months after the first lunar landing in October 1969, showed that 56% of Americans thought the government should be spending less money on space exploration, and only 10% thought the government should be spending more money. There was no longer public recognition of the benefits of space (or lunar) exploration. US President Nixon, his administration, Congress and the press soon followed in showing disinterest for the space programme. Exploration of the Moon could no longer hold Americans' attention. There were just too many things happening closer to home. The years of Apollo were also the years of demonstration for the civil rights movement, the years of political unrest with Martin Luther King and Robert Kennedy being slain, along with thousands of Americans in Vietnam. If water is eventually found to be feasibly extractable, then this factor alone might make the whole idea of travelling to the Moon and using its resources again more appealling. The Moon Contents