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Home , Apollo (crater), Apollo 13, Apollo 16, Apollo 17, Apollo 4, Apollo 5

Exploring the

Lecture 4: Exploration of the

Professor Paul Sellin Department of Physics University of Surrey Guildford UK

Page 1 Paul Sellin

Lecture 4 Page 1 Overview

Exploration of the Moon:

 Moon probes: Luna, Ranger and Lunar Orbiter programmes

: the first controlled landing on the Moon

: manned to the Moon

 Samples from the Moon – lunar

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Lecture 4 Page 2

Lunar missions covered the period 1959 to the 1990s:  , 2, 3 sent in 1959 by the to approach the Moon  Project Ranger started in 1960 by the US, transmitting close-up views of the Moon’s surface before crashing into the Moon  Lunar Orbiter programme: 5 from 1966-1967 competed a high resolution photographic survey of the Moon’s surface, showing features as small as 1m. This data was used to select possible landing sights for the Apollo landings  Surveyor programme: 5 unmanned spacecraft landed on the Moon during 1966-1968. Data from these spacecraft proved that the Moon’s surface was solid, and not a thick layer of dust  Apollo consisted of 6 manned landings on the Moon – in followed by -17, landing in progressively more challenging terrain  Unmanned Soviet spacecraft landed on the Moon from 1966 – 1976, with landing 4 after the US in 1966. In the Luna spacecraft landed vehicles which explored the surface, and returned rock samples to spent 2 months observing the Moon in 1994, carrying various UV/Vis/IR imaging cameras which revealed the atomic composition of large areas of the Moon’s surface

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Lecture 4 Page 3 Ranger programme

The Ranger project of the 1960s was the first U.S. effort to launch probes directly toward the Moon. Ranger spacecraft were equipped with 6 TV cameras which transmitted close-up view of the Moon before they crash-landed into its surface. A variety of difficulties plagued the first several attempted missions in this series, but the Rangers 7-9 were a complete success : Launched 23 August 1961 Failed to leave Earth parking

Ranger 2: Launched 18 November 1961 Failed to leave Earth

Ranger 3: Launched 26 January 1962 Earth contact lost, missed the Moon by ~36,800 km

Ranger 4: Launched 23 April 1962 Sequencer failed, impacted the Moon 26 April 1962

Ranger 5: Launched 18 October 1962 Earth contact lost, missed the Moon by 725 km

Ranger 6: Launched 30 Cameras failed, impacted the Moon 2 February 1964

http://www.jpl.nasa.gov/missions/past/ranger.htmlPage 4 Paul Sellin

Ranger 1 was launched from , , on August 23, 1961, followed by the launch of on November 18 of that year. In both cases, the Agena B engine failed to restart and both spacecraft reentered Earth's atmosphere a short time later. was launched January 26, 1962, but an inaccuracy put it off course and it missed the Moon. had a perfect launch on April 23 of that year, but the spacecraft was completely disabled. The project team tracked the seismometer capsule to impact just out of sight on the , validating the spacecraft's communications and navigation system. missed the Moon following its launch on October 18, 1962, and was disabled. was launched January 30, 1964, and had a flawless flight culminating in impact as planned on the Moon; its system, however, was disabled by an in-flight accident and could take no pictures. The next three Rangers, with a redesigned television, were completely successful. was launched July 28, 1964, and sent more than 4,300 pictures on its way down to target in a lunar plain, soon named , south of the crater Copernicus. Following launch on , 1965, successfully completed its mission with a planned crash-landing in , where the Apollo 11 would land 4-1/2 years later. Ranger 8 garnered more than 7,300 images. Ranger 9 was launched March 21, 1965, and impacted the Moon in the 90- kilometer-diameter (75-mile) crater , sending more than 5,800 images.

Lecture 4 Page 4 Ranger images (1)

The last two pictures taken by Ranger 9 before impact onto the lunar surface on the floor of Alphonsus crater. The top image was taken at a distance of 600m 0.25s before impact. The frame is about 70 m across. The lower frame includes most of the area on the left of the Ranger 9 view of crater Alphonsus upper image and was taken 3 minutes before impact, at a from 1.2km 4.5s prior to impact. distance of 442km The image is approximately 50 meters across.

http://www.jpl.nasa.gov/missions/past/ranger.htmlPage 5 Paul Sellin

Ranger 9 image of Alphonsus crater (diameter 108 km) from a distance of 442 km, taken about 3 minutes before impact in the upper right portion of the crater. At left is the northeastern edge of . The crater adjacent to Alphonsus at the bottom is the 39 km diameter . crater is at upper left. North is at 12:30. Ranger 9 impacted the Moon on 24 at 14:08:20 UT.

Lecture 4 Page 5 Ranger images (2)

Ranger 9 image from 2500 km showing Ranger 9 image taken 54 seconds before impact, at Ptolemaeus, Alphonsus, and 136km. The raised area at lower center is the central craters. peak of Alphonsus crater floor.

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(left) Ptolemaeus is the large (164 diameter) flat-floored crater at the top. Alphonsus, diameter 108 km, is at lower left and the 114 km Albategnius crater is at lower right. The runs through the lower corner. Ranger 9 impacted in Alphonsus crater 18.5 minutes after this image was taken. North is at 12:30

(right) This image was taken from a distance of 136 km. The impact point of Ranger 9 is to the right of the central reticle, about 60% of the way from the central reticle to the edge of the frame. The image is 60 km across and north is at 12:30.

Lecture 4 Page 6 Lunar Orbiter

5 Lunar Orbiters sent back a total of 2180 high resolution and 882 medium resolution images of the Moon’s surface, covering 99.5% of the Moon’s surface with resolution down to 1m. The experiments recorded 22 impacts showing the average micrometeoroid flux near the Moon was about two orders of magnitude greater than in interplanetary space but slightly less than the near Earth environment.

The radiation experiments confirmed that the design of Apollo hardware would protect the astronauts from average and greater-than-average short term exposure to solar particle events.

Page 7 Paul Sellin http://nssdc.gsfc.nasa.gov/database/MasterCatalog?sc=1967-075A

Lunar Orbiter 5, the last of the Lunar Orbiter series, was designed to take additional Apollo and Surveyor landing site photography and to take broad survey images of unphotographed parts of the Moon's far side. It was also equipped to collect radiation intensity, and micrometeoroid impact data and was used to evaluate the Manned Space Flight Network tracking stations and Apollo Orbit Determination Program. The spacecraft was placed in a cislunar trajectory and on 5 August 1967 was injected into an elliptical near polar 194.5 km x 6023 km with an inclination of 85 degrees and a period of 8 hours 30 minutes. On 9 August the orbit was lowered to a 99 km x 1499 km, 3 hour 11 minute period. The photographic portion of the mission ended on 18 August. The spacecraft acquired photographic data from August 6 to 18, 1967, and readout occurred until August 27, 1967. A total of 633 high resolution and 211 medium resolution frames at resolution down to 2 meters were acquired, bringing the cumulative photographic coverage by the 5 Lunar Orbiters to 99% of the Moon's surface. Accurate data were acquired from all other experiments throughout the mission. The spacecraft was tracked until it impacted the lunar surface on command on January 31, 1968. The use of Lunar Orbiters for tracking to evaluate the Manned Space Flight Network tracking stations and Apollo Orbit Determination Program was successful, with three Lunar Orbiters (2, 3, and 5) being tracked simultaneously from August to October 1967. The Lunar Orbiters were all eventually commanded to crash on the Moon before their gas ran out so they would not present navigational or communications hazards to later Apollo flights.

Lecture 4 Page 7 crater

Lunar Orbiter 5 image of the plateau -northwest of Marius crater on the Moon. Note the two sinuous which cut across a ridge at the center of the image. Also visible are volcanic domes and cones. The round "cobra-" feature at the center left is roughly 2.5 km in diameter. The image is 80 km across and north is at 2:30

All Lunar Orbiter images from: http://nssdc.gsfc.nasa.gov/imgcat

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Lecture 4 Page 8 crater

Lunar Orbiter 5 view of Aristarchus crater on the Moon. The crater is approximately 40 km in diameter, and 3.6 km in depth from rim to floor. Note the hummocky ejecta blanket surrounding the crater and the concentric and radial valleys along the crater walls, resulting from mass wasting. North is up.

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Lecture 4 Page 9 Procellarum

Lunar Orbiter 5 view of a chain of elongated craters and low mounds in northern on the Moon. The chain continues to the south (down) of this image as a mare ridge. The chain may have been formed by upwelling of material along a line of weakness resulting in extension to form mounds, and collapse to form the elongated craters. The crater at the upper left is about 7 km in diameter.

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Lecture 4 Page 10 Hadley

Lunar Orbiter 5 view of Hadley Rille and the surrounding region on the Moon. Hadley Rille is the sinuous depression running from the top to the bottom of the image. To the right are the 1 to 2 km high Apennine mountains. landed near the very rightmost extension of the rille, near the top of the image. The large crater in the center of the image is the 30 km diameter Hadley C. A high resolution image of the rille is shown on the next slide

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Lecture 4 Page 11 Hadley Rille (hi res)

Lunar Orbiter 5 view of Hadley Rille (Rima Hadley) on the Moon. This high-resolution view of the V- shaped clearly shows blocks along the walls and at the bottom. The sides slope at about 20 degrees, and the rille is 1 to 1.5 km from rim to rim. Apollo 15 landed about 2 km from the rim of Hadley Rille and explored it in detail. North is up. This is a detail from the lower left corner of the previous image

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Lecture 4 Page 12 Surveyor programme

The Surveyor spacecraft was the first U.S. effort to make a soft landing on the Moon. The missions would test a new high-energy / rocket and a new spacecraft design; two-way communications to control spacecraft activities from the ground; and a new and elegant landing method, with three steerable rocket engines controlled by onboard . Surveyor 1 landed on the Moon at a site called in Oceanus Procellarum on June 2 1966. Surveyor 1 sent 11,240 pictures, revealing details as small as 2 millimeters (1/12th inch). The operated until January 7, 1967. and 4 suffered problems, however , 5, 6 and 7 landed successfully in various sites and performed chemical analysis on Moon soil using a robot arm scoop. Almost 90,000 images were acquired from five sites. visited Surveyor 3 2½ years after it landed. Pieces retrieved from the spacecraft were analysed on Earth for micrometeroid impacts.

http://nssdc.gsfc.nasa.gov/plPage 13 anetary/lunar/surveyor.html Paul Sellin

Surveyor 1 was launched from Cape Canaveral, Florida, on May 30, 1966, settling down on the Moon at a site called Flamsteed in Oceanus Procellarum on June 2. Surveyor 1 sent 11,240 pictures, revealing details as small as 2 millimeters (1/12th inch). The lander operated until January 7, 1967. Surveyor 2 was not as successful. Following its launch on September 20, 1966, it crashed into the Moon three days later. was launched July 14, 1967, but its signal was lost 2-1/2 minutes after lunar impact. Surveyor 3, 5, 6 and 7 repeated the initial triumph of Surveyor 1 in different sites and successively added a robot arm with scoop and a chemical element analyzer to the scientific toolkit. Surveyor 3 was launched April 17, 1967, and operated on the Moon until May 4, 1967. was launched September 8, 1967 and lasted until December 17 of that year. was launched November 7, 1967 and operated until , 1967. was launched January 7, 1968 and lasted until February 21 of that year. All told they acquired almost 90,000 images from five sites. Surveyor 3 participated in the only lunar surface rendezvous when the Apollo 12 astronauts landed nearby in . The crew visited the 2-1/2- year-old , photographed it and the site and brought some of its parts back to Earth.

Lecture 4 Page 13 Optical imaging and the Small Angle Formula*

Why do a bird and plane appear the same ‘size’ when flying in the sky?

The sine function gives:

Small angle approximation assumes (1) sin , (2) hypotenuse ~ d, hence: Using D in km and  in arcseconds the equation is re-scaled to give:

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Lecture 4 Page 14 Small Angle Formula Example*

On July 26, 2003, was 943 million kilometers from Earth and had an angular diameter of 31.2”. Using the small-angle formula, determine Jupiter’s actual diameter.

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Lecture 4 Page 15 CCD cameras

CCDs, or Charge Coupled Devices, are the most common form of high resolution imaging detector:  Based on silicon, the primary interaction (light or X- ray photons) generates charge in each pixel.  The CCD transfers the accumulated charge to an external amplifier using a series of shift registers. To detect optical light:  a CCD is highly sensitive to optical photons over a wavelength range of 400nm – 900nm (visible light)  special CCDs called ‘back thinned’ can extend the UV and IR range to 200nm – 1100nm

The ccd camera in the XMM- satellite has 384x400 pixels arranged over 6x2 chips To detect X-rays and gamma rays:  Normally a scintillating layer is deposited on the surface of the CCD, consisting of a high-Z material with a good stopping efficiency for X-rays. The scintillator produces a corresponding light flash which is detected by the CCD. Page 16 Paul Sellin

Lecture 4 Page 16 Imaging resolution of ’s cameras*

The Cassini spacecraft carries several imaging cameras. The resolution of the images is defined by the angular resolution of the camera:  the pixel resolution of the image is limited by the granularity of the CCD imaging sensor in the camera  in Cassini the CCD sensor has an active area of 12.3x12.3 mm, and contains 1024x1024 pixels  the effective angular resolution  of the camera defines the smallest object which can be observed on :

 In the Cassini instrument the camera focal length 1700mm If Cassini flys 1200km above Titan, calculate the size of the smallest object which can be imaged:

One of the Cassini CCD imaging arrays

So the minimum resolvable object size D is:

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Lecture 4 Page 17 Diffraction limited resolution*

In principle the imaging resolution of a spacecraft camera can be improved by any of:  decreasing the pixel size (increasing the granularity of the CCD sensor)  using a longer focal length lens – reduces the field of view (FOV) but increases the optical magnification However eventually the intrinsic diffraction-limited resolution of the camera is reached, and no further improvement to the optical system will help. This is limited by the Rayleigh Criterion and the F/number of the camera system:

 the Rayleigh criterion for diffraction-limited resolution Ray is

 the F/number quantifies the ability of the lens to collect light:

The Cassini camera has F/8.5, hence the diffraction limited resolution at 650nm is:

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Lecture 4 Page 18 Panorama image of crater – Surveyor 7

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The TV camera consisted of a vidicon tube, 25- and 100-mm focal length lenses, shutters, polarizing filters, and iris mounted nearly vertically and surmounted by a mirror that could be adjusted by stepping motors to move in both azimuth and elevations. The polarizing filters served as anaylzers for the detection of measurements of the linearly polarized component of light scattered from the lunar surface. The frame-by-frame coverage of the lunar surface provided a 360- deg azimuth view and an elevation view from approximately +90 deg above the plane normal to the camera A axis to -60 deg below this same plane. Both 600-line and 200-line modes of operation were used. The 200-line mode transmitted over an omnidirectional antenna and scanned one frame each 61.8 sec. A complete video transmission of each 200-line picture required 20 sec and utilized a bandwidth of 1.2 kHz. Most transmissions consisted of 600-line pictures, which were telemetered by a directional antenna. The frames were scanned each 3.6 sec. Each frame required nominally 1 sec to be read from the vidicon and utilized a 220-kHz bandwidth for transmission. The dynamic range and sensitivity of this camera were slightly less than those on the Surveyor 6 camera. Resolution and quality were excellent. These data were recorded on a video magnetic tape recorder and on 70-mm film. The camera transmitted 20,961 pictures during the first lunar day, January 10 to 22, 1968. During the second lunar day, 45 pictures were transmitted before loss of power caused suspension of camera operation.

Lecture 4 Page 19 Alpha particle scattering instrument on Surveyor

The alpha-scattering surface analyzer was designed to measure directly the abundances of the major elements of the lunar surface. The instrument used a collimated alpha source ( 242) to irradiate a 1cm diameter opening in the bottom of the instrument where the sample was located. Two independent silicon detector systems measured: (1) the energy spectra of the alpha particles scattered from the lunar surface, (2) the energy spectra of protons produced via reaction (alpha and proton) in the surface material. Each detector assembly was connected to a pulse height analyzer, and the data were continuously telemetered to Earth. The spectra contained quantitative information on all major elements in the samples except for , , and lithium. The experiment provided from various lunar-surface samples, including undisturbed local lunar surface, a lunar rock, and an extensively trenched area of the lunar surface. Data were obtained from Surveyor 5 (Sep 1967), Surveyor 6 (Nov 1967) and Surveyor 7 (Jan- Feb 1968).

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Lecture 4 Page 20 The Surveyor alpha particle instrument

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Lecture 4 Page 21 Alpha particle scattering

The technique (also called Rutherford Back Scattering, or RBS) used large-angle scatter of alpha particles, due to scatter off the nucleus of the target material (Geiger and Marsden). The

fraction of kinetic energy remaining for a scattered alpha particle Tm/T0 depends on: 1. the scattering angle  In a simple instrument the 2. the mass number of the nucleus A scatter angle  is fixed by the collimation around the detector, 2 such that:  2 2 1/ 2  and the distance to the sample Tm 4cos  A 16sin     (the lunar surface) T A  4 0  

For an ideal ‘thin’ sample, a monoenergetic scatter fraction would be observed, at fixed  If the scatter plane is buried below the surface, the alpha energy is reduced both before and after the scatter event In reality, this creates a ‘flat’ energy spectrum with a

maximum energy Tm which is characteristic of the atomic mass A of the material.

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Lecture 4 Page 22 Scattering angle and resolution

Plotting the fraction Tm/T0 as a function of scattering angle shows the resolving power of this technique:  the greatest resolution between elements is achieved at a scattering angle of 180°, although there is very little change beyond 160°  the resolution decreases rapidly with increasing mass number (heavier elements) The Surveyor instruments could resolve elements up to calcium (A=40, Z=20)

Proton spectra from (,p) reactions provided complementary data for important elements such as Na, Mg and Al, which have a low probability for  scattering

Calculated plot of the fraction Tm/T0 as a function of scattering angle  Page 23 Paul Sellin

Lecture 4 Page 23 The

The Apollo program was designed to land on the Moon and bring them safely back to Earth. Six of the missions ( 11, 12, 14, 15, 16, and 17) achieved this goal. Apollos 7 and 9 were Earth orbiting missions to test the Command and Lunar Modules, and did not return lunar data. Apollos 8 and 10 tested various components while orbiting the Moon, and returned photography of the lunar surface. did not land on the Moon due to a malfunction, but also returned photographs. The six missions that landed on the Moon returned a large amount of scientific data and almost 400 kilograms of lunar samples. Experiments included soil mechanics, , seismic, heat flow, lunar ranging, magnetic fields, and solar wind experiments There were large number of preceding un-manned Apollo test flights, culminating in in 1968. These earth orbit missions were used to test the launch and re-entry systems of the /Apollo spacecraft http://nssdc.gsfc.nasa.gov/planetary/lunar/apollo.html

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Apollo Uncrewed Earth Orbiting Missions : Launched 9 , first all-up launch of : Launched 22 January 1968, first test of Lunar Module in space Apollo 6: Launched 4 , final uncrewed Apollo test flight

Apollo Crewed Earth Orbiting Missions Launched 11 October 1968: First crewed Apollo flight, 22 October 1968 Launched 03 March 1969: First crewed Lunar Module test, splashdown 13 March 1969

One of the worst tragedies in the occurred on January 27, 1967 when the crew of Gus , Ed , and Roger were killed in a fire in the Apollo Command Module during a preflight test at Cape Canaveral. They were training for the first crewed Apollo flight, an Earth orbiting mission scheduled to be launched on 21 February. They were taking part in a "plugs-out" test, in which the Command Module was mounted on the Saturn 1B on the launch pad just as it would be for the actual launch, but the Saturn 1B was not fueled. The plan was to go through an entire countdown sequence. The mission, originally designated Apollo 204, was officially assigned the name "“. The first Saturn V launch (uncrewed) in November 1967 was designated Apollo 4 (no missions were ever designated Apollo 2 or 3).

Lecture 4 Page 24 Summary of the Apollo landings 1969-1972

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Lecture 4 Page 25 Apollo image of the Earth

Apollo 17 hand-held Hasselblad picture of the full Earth. This picture was taken on 7 , as the spacecraft traveled to the moon, the last of the Apollo missions. A remarkably cloud-free Africa is at upper left, stretching down to the center of the image. Saudi Arabia is visible at the top of the disk and Antarctica and the south pole are at the bottom. Asia is on the horizon is at upper right. The Earth is 12,740 km in diameter.

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Lecture 4 Page 26 Apollo 11 – the first

Apollo 11 was the first mission in which humans walked on the lunar surface and returned to Earth.  On 20 July 1969 two astronauts (Apollo 11 Commander Neil A. and LM pilot Edwin E. "Buzz" Jr.) landed in the Sea of Tranquility on the Moon in the Lunar Module  The Command and (CSM) (with CM pilot Michael ) continued in lunar orbit.  During their stay on the Moon, the astronauts set up scientific experiments, took photographs, and collected lunar samples.  The LM took off from the Moon on 21 July and the astronauts returned to Earth on 24 July.

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Lecture 4 Page 27 Apollo 11 Lunar Module ‘Eagle’

The Apollo 11 Lunar Module (LM) "Eagle" was the first crewed vehicle to land on the Moon, and carried two astronauts, Also included on the LM was the Early Apollo Scientific Experiment Package (EASEP), which consisted of several self-contained experiments to be deployed and left on the lunar surface, and other scientific and sample collection apparatus.

Armstrong stepped onto the lunar surface at 02:56:15 UT on 21st July 1969 stating, "That's one small step for man, one giant leap for mankind".

The astronauts traversed a total distance of about 250 meters, both ranging up to about 100 meters from the LM. They took two core tube samples of and packed these along with the lunar samples and the solar wind experiment into the sample boxes.

The LM lifted off from the Moon at 17:54:01 UT after 21 hours, 36 minutes on the lunar surface

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Lecture 4 Page 28 steps on the Moon

Apollo 11 Lunar Module pilot Edwin Aldrin climbs down the ladder to the Moon's surface as photographs his descent. Edwin Aldrin stepped onto the surface at 03:15 UT on 21 July 1969 and became the second person to walk on the Moon.

All moon images from: http://nssdc.gsfc.nasa.gov/imgcat

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Lecture 4 Page 29 Buzz Aldrin steps on the Moon

Apollo 11 astronaut Edwin Aldrin stands facing the U.S. on the Moon. The rod to hold the flag out horizontally would not extend fully, so the flag ended up with a slight waviness, giving the appearance of being windblown. The flag itself was difficult to erect, it was very hard to penetrate beyond about 6 to 8 inches into the lunar soil with the flagstaff.

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Lecture 4 Page 30 Armstrong at the Module

Apollo 11 astronaut Neil Armstrong packing lunar samples in the Modular Equipment Stowage Assembly (MESA). One of the few photographs showing him on the Moon since Armstrong took most of the photographs on the Moon. Armstrong is in the shadow of the lunar module, details can only be seen with processing, making the sunlit surface directly behind the LM appear very bright.

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Lecture 4 Page 31

An area of Tranquility Base taken from the Apollo 11 lunar module at the end of the astronaut's 2 1/2 hour moonwalk. The lunar television camera is visible beyond the flag. Footprints cover most of the area. A lunar module thruster blocks part of this view, looking roughly northwest. The astronauts took off from the Moon at 17:54 UT (1:54 p.m. EDT) on 21 July 1969.

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Lecture 4 Page 32

Apollo 17 was the sixth and last Apollo mission in which humans walked on the lunar surface. On 11 December 1972 two astronauts (Commander Eugene A. Cernan and LM pilot Harrison H. Schmitt, the first scientist on the Moon) landed in the Taurus- region of the Moon in the Lunar Module (LM). The Command and Service Module (CSM) (with CM pilot Ronald E. ) continued in lunar orbit. During their stay on the Moon, the astronauts set up scientific experiments, took photographs, and collected lunar samples. The LM took off from the Moon on 14 December and the astronauts returned to Earth on 19 December.

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Image: Southward looking oblique view of and Copernicus crater on the Moon. Copernicus crater is seen almost edge-on near the horizon at the center. The crater is 107 km in diameter and is centered at 9.7 N, 20.1 W. In the foreground is Mare Imbrium, peppered with secondary crater chains and elongated craters due to the Copernicus impact. The large crater near the center of the image is the 20 km diameter , at 20.5 N, 20.6 W. At the upper edge of the Mare Imbrium are the . The distance from the lower edge of the frame to the center of Copernicus is about 400 km. This picture was taken by the metric camera on Apollo 17.

Lecture 4 Page 33 Lunar Rovers

The (LRV) was an electric vehicle designed to operate in the low- gravity vacuum of the Moon and to be capable of traversing the lunar surface, allowing the Apollo astronauts to extend the range of their surface extravehicular activities.

Three LRVs were driven on the Moon, during the Apollo 15, 16 and 17 missions.

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Each rover was used on three traverses, one per day over the three day course of each mission. On Apollo 15 the LRV was driven a total of 27.8 km in 3 hours, 2 minutes of driving time. The longest single traverse was 12.5 km and the maximum range from the LM was 5.0 km. On the vehicle traversed 26.7 km in 3 hours 26 minutes of driving. The longest traverse was 11.6 km and the LRV reached a distance of 4.5 km from the LM. On Apollo 17 the rover went 35.9 km in 4 hours 26 minutes total drive time. The longest traverse was 20.1 km and the greatest range from the LM was 7.6 km. The Lunar Roving Vehicle had a mass of 210 kg and was designed to hold a payload of an additional 490 kg on the lunar surface. The frame was 3.1 meters long with a wheelbase of 2.3 meters. The frame was made of aluminum alloy 2219 tubing welded assemblies and consisted of a 3 part chassis which was hinged in the center so it could be folded up and hung in the Lunar Module quad 1 bay. It had two side-by-side foldable seats made of tubular aluminum with nylon webbing and aluminum floor panels. An armrest was mounted between the seats, and each seat had adjustable footrests and a velcro seatbelt. A large mesh dish antenna was mounted on a mast on the front center of the rover. The suspension consisted of a double horizontal wishbone with upper and lower torsion bars and a damper unit between the chassis and upper wishbone. Fully loaded the LRV had a ground clearance of 36 cm.

Lecture 4 Page 34 Deployment of the

The image shows an artist impression of the planned deployment of the lunar rover

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Deployment of the LRV from the LM quad 1 by the astronauts was achieved with a system of pulleys and braked reels using ropes and cloth tapes. The rover was folded and stored in quad 1 with the underside of the chassis facing out. One astronaut would climb the egress ladder on the LM and release the rover, which would then be slowly tilted out by the second astronaut on the ground through the use of reels and tapes. As the rover was let down from the bay most of the deployment was automatic. The rear wheels folded out and locked in place and when they touched the ground the front of the rover could be unfolded, the wheels deployed, and the entire frame let down to the surface by pulleys. The rover components locked into place upon opening.

Lecture 4 Page 35 Moon landings map

Where are they now? The Apollo Command Module Capsules are on display at various sites throughout the U.S. and the . The command module is at the Science Museum – the only Apollo module outside the US. The Apollo Lunar Modules were deliberately targeted to impact the Moon to provide artificial moonquake sources for seismic experiments.

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Lecture 4 Page 36 Volcanic activity on the Moon

Apollo 17 surface photo showing orange soil discovered during the 2nd EVA near Crater at the Taurus-Littrow landing site on the Moon.

Upon close examination on Earth, the soil was seen to contain many orange volcanic glass particles, giving it its distinctive color. The tripod at left center is a gnomon and photographic reference chart. This picture was taken on 12 December 1972

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Each rover was used on three traverses, one per day over the three day course of each mission. On Apollo 15 the LRV was driven a total of 27.8 km in 3 hours, 2 minutes of driving time. The longest single traverse was 12.5 km and the maximum range from the LM was 5.0 km. On Apollo 16 the vehicle traversed 26.7 km in 3 hours 26 minutes of driving. The longest traverse was 11.6 km and the LRV reached a distance of 4.5 km from the LM. On Apollo 17 the rover went 35.9 km in 4 hours 26 minutes total drive time. The longest traverse was 20.1 km and the greatest range from the LM was 7.6 km. The Lunar Roving Vehicle had a mass of 210 kg and was designed to hold a payload of an additional 490 kg on the lunar surface. The frame was 3.1 meters long with a wheelbase of 2.3 meters. The frame was made of aluminum alloy 2219 tubing welded assemblies and consisted of a 3 part chassis which was hinged in the center so it could be folded up and hung in the Lunar Module quad 1 bay. It had two side-by-side foldable seats made of tubular aluminum with nylon webbing and aluminum floor panels. An armrest was mounted between the seats, and each seat had adjustable footrests and a velcro seatbelt. A large mesh dish antenna was mounted on a mast on the front center of the rover. The suspension consisted of a double horizontal wishbone with upper and lower torsion bars and a damper unit between the chassis and upper wishbone. Fully loaded the LRV had a ground clearance of 36 cm.

Lecture 4 Page 37 Water on the Moon

In 1994, the NASA Clementine spacecraft orbited the Moon and mapped its surface. In one experiment, Clementine beamed radio signals into shadowed craters near the Moon's south pole. The reflections, received by antennas on Earth, seemed to come from icy material.

If there is water on the Moon, it's must be frozen in the permanent shadows of deep polar craters.

However the Clementine data were not conclusive, and when astronomers tried to find in the same craters using the giant Arecibo radar in Puerto Rico, they couldn't.

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As preparations were underway in the mid 1960s for the Apollo program, geologists and astronomers were divided as to whether the lunar surface was a result of volcanic forces from beneath, or cosmic forces from above. Increasingly the favoured theory was that large asteroidal objects hit the Moon, forming its craters. Ralph Baldwin supported this theory in 1949, and Gene Shoemaker revived the idea again around 1960. Shoemaker, almost alone among geologists of his day, saw the Moon as a fertile subject for field geology. He saw the craters on the Moon as logical impact sites that were formed not gradually in eons, but explosively in seconds.

The Apollo flights confirmed that the dominant geological process on the Moon is impact-related. The favoured theory for the existence of water on Earth is that hydrogen and were deposited on Earth during its early history--mostly during the period of "" 3.9 billion years ago--by the impacts of and . Because the Moon shares the same area of space as Earth, it should have received its share of water as well. However, since it has only a tiny fraction of Earth's gravity, most of the Moon's water supply should have evaporated and drifted off into space long ago. And are the still remains of water on the Moon today?

Ref: http://science.nasa.gov/headlines/y2005/14apr_moonwater.htm

Lecture 4 Page 38 The lunar poles

This Clementine topographic map of the Moon (red=high, purple=low -- each colour equals 500 meters of elevation), shows the extent of the South Pole- basin. The basin is about 2500 km across and 13 km deep. Because the south pole occurs just inside the rim of this deep hole, these regions are just below the "solar horizon" of the Moon and large areas of permanent darkness occur near the south pole.

These composite images (left) are made up of many different and show the lighting conditions at the north and south poles of the Moon throughout one lunar day. Ref: http://www.psrd.hawaii.edu/Dec96/IceonMoon.html

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Note that for the north pole (left image), virtually every area gets some sunlight during some part of the lunar day. However, large areas of the south pole appear to be permanently dark ( on right polar image).

It has been calculated that temperatures in these permanently dark areas may be as cold as 40 to 50 Kelvin (-230o to -220o C),

Lecture 4 Page 39 Water on the Moon (2)

Lunar orbited the Moon in 1998. Using a neutron spectrometer, scanned the Moon's surface for hydrogen-rich minerals. Polar craters showed a high neutron signal, consistent with hydrogen. It is very likely that this is evidence for H2O

In July 1999 Lunar Prospector was deliberately crashed into the lunar surface near the Moon's south pole. NASA hoped that this impact would produce an observable plume of water vapour from near surface ice.

Lunar Prospector crashed as planned, however no vapour cloud was observed. This indicates:  there was no water  or there was not enough water to be detected by Earth-based telescopes Hydrogen deposits measured by Lunar  or the telescopes were not looking in Prospector precisely the right place

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Neutron spectroscopy, the method which Lunar Prospector mission scientists are using to search for water ice on the Moon, hinges upon the detection of -- not surprisingly -- small particles of energy called neutrons which continually emanate from the lunar surface. Actually, there are three energy ranges for such neutrons which the neutron spectrometer can detect: low-energy "thermal" neutrons, medium-energy "epithermal" neutrons and high-energy "fast" neutrons.

The key to finding evidence of water with this technique is how each neutron type interacts with wet lunar soil vs. dry lunar soil. Lunar soil containing water (and therefore an abundance of hydrogen ) is much better at moderating epithermal and fast neutrons. In the figure above, note the coincident dips in medium-energy neutrons at both lunar poles (see arrows). This is a definitive signature for water. Based on the extent of the dips, mission scientists estimate that the total amount of water on the Moon could be anywhere from 10 to 300 million metric tons (2.6 to 26 billion gallons). Ref: http://lunar.arc.nasa.gov/

Lecture 4 Page 40 Lunar Reconnaissance Orbiter

In 2008, NASA plans to send a new spacecraft to the Moon: the Lunar Reconnaissance Orbiter (LRO). LRO will contain sensors that can sense water in at least four different ways. LRO is part of the US aim to return humans to the Moon as early as 2015

Main science objectives of LRO:

•Characterization of deep space radiation in Lunar orbit • Geodetic global topography • High spatial resolution hydrogen mapping • Temperature mapping in polar shadowed regions • Imaging of surface in permanently shadowed regions • Identification of near-surface water ice in polar cold traps • Assessment of features for landing sites • Characterization of polar region lighting environment Ref: http://lunar.gsfc.nasa.gov/missions/ Launch date for LRO is 31 October 2008

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