lunar exploration – Australian Science

Apollo 17: last men on the moon

Kevin Orrman-Rossiter — Tue, 18 Dec 2012 00:03:17 +0000

Apollo 17 Commander, Eugene Cernan, next to the lunar rover. Image credit NASA.

After kangaroo hopping back to the lunar rover, Eugene and Jack drove back to the lunar module, Challenger. There they dusted each other off and loaded the last of their 100kg of lunar rock samples. Jack cleaned up inside While Eugene parked the rover a kilometre and a half away so the takeoff could be televised. Then hopping and skipping in the low lunar gravity he made the most of his last moments on the moon. Once back at the lunar module, one foot on the Challenger’s landing pad, Eugene Cernan lifted his other from the moon, and said:

As I take these last steps from the surface for some time to come, I’d just like to record that America’s challenge of today has forged man’s destiny of tomorrow.

The next day, December 14, 1972, they blasted off from the moon, ending the sixth and last human exploration of the moon for the 20th century.

The last of the lunar Apollos

The Apollo program was a child of the cold war between the USA and Soviet Russia. It was invigorated by President Kennedy’s 1961 challenge to put man on the moon and return him safely before the decade was over. Once the landing of Apollo 11 was achieved in July 1969, the Apollo and NASA budgets came under savage scrutiny. It was the time of the war in Vietnam, budget problems for the 1972 fiscal year and followed the scare of Apollo 13.

The final two scheduled Apollo missions, 18 and 19, were finally cancelled in September 2, 1970. Apollo 20 had already been cancelled on January 2 so that its Saturn V rocket could be used as the launch vehicle for the Skylab space-station in 1973.

The first part of the return journey as the Lunar module, Challenger, approaches Apollo 17 Command Service Module, America, after blasting off the lunar surface. Photo credit NASA

The Apollo program was an incredible, successful human feat. It remains the only program to have placed humans beyond low-earth orbit and onto another celestial body. Apollo 8 was the first manned spacecraft to orbit another celestial body, while Apollo 11 landed the first humans on another world. The program returned 382 kg of lunar rocks and soil to Earth, contributing to the understanding of lunar geology.

It laid the foundation for NASA’s current human spaceflight capability, and funded construction of its Johnson Space Center and Kennedy Space Center. Apollo also spurred advances in many areas of technology incidental to rocketry and manned spaceflight and the start of huge opportunities for technology transfer, leading to more than 1,500 successful spinoffs related to areas as disparate as heart monitors, solar panels, and cordless innovation. More recently, we’ve seen a fledgling private-sector American space industry complete its first cargo delivery to the international space station.

Stepping up, walking tall

There is a marvelous fascination with human exploration. The Apollo missions are a great representation of that drive and curiosity. Apollo 17 astronauts, Eugene Cernan, Harrison Schmitt and Ron Evans, exemplified those attributes.

Publicity shot of the Apollo 17 crew with their Saturn V vehicle in the background. (L-R): jack Schmitt, Eugene Cernan (seated) and Ron Evans.

Eugene Cernan is ‘Captain America’ to a tee. A US Navy pilot who, like much of America, was caught up in the early space race. In 1962 he watched, captivated, on TV the launch of John Glenn. Who in the third manned Mercury capsule became the first American to orbit the earth. Cernan at the time lacked the coveted ‘test-pilot’ wings to be selected in the September 1962 second group of astronauts, which included Apollo 11 commander, Neil Armstrong. Cernan was picked, in October 1963, for the third astronaut group – which included the other Apollo 11 astronauts Buzz Aldrin and Michael Collins.

Cernan became the second American astronaut, after Ed White on June 3 1965, to perform an extra-vehicular activity – a spacewalk. His Gemini 9 spacewalk lasted 2 hours and nine minutes, travelling 57,600 km, and rated as one most difficult achievements of his life. The brutal mechanics of Newton’s third law in action in space making seemingly simple tasks into exhausting and challenging experiences, resulting in fogging his helmet and pushing his heart rate to 188 bpm. His experiences made NASA rethink the training required for future extra-vehicular activities.

Gemini 9 splashdown with Eugene Cernan (L) and a smiling Tom Stafford (R).

On January 27, 1967 Tom Stafford, John Young and Cernan were in an altitude chamber “trying to bring a new, untried, stubborn spacecraft up to launch standards”. Meanwhile, in an identical craft, Apollo 1 astronauts veteran Gus Grissom, first American spacewalker Ed White and Cernan’s closest friend the rookie Roger Chaffee, were conducting similar tests atop a Saturn rocket at Cape Kennedy. Minutes later they were dead, killed in a fire – a tragedy stunning the close-knit space community.

In May 1969, Cernan, as part of the Apollo 10 crew along with Tom Stafford and John Young achieved a number of records and a “dry-run” for the Apollo 11 landing two months later. As befitting a crew of test pilots they set the record for the highest speed attained by a manned vehicle at 39,897 km/h during the return from the Moon on May 26, 1969 and hold the record of being the humans who have traveled to the farthest point away from home, some 408,950 kilometres. Cernan and Stafford came within 15.6km of the lunar surface in their lunar module Snoopy.

Jack Schmitt being suited up for dress rehearsal prior to launch. Photo credit NASA.

Harrison “Jack” Schmitt is a geologist and one of the NASA group 4 astronauts, “the scientists“, that were announced on June 28, 1965. His and their story is worthy of is own post, coming in January 2013.

Ron Evans having a suit fitting during the pre-launch phase. Photo credit NASA.

Ron Evans was picked as a Command Module specialist from the beginning of his NASA career. Chosen in April 1966, one of the group 5 astronauts, he was support crew for Apollo 1 and back-up command module pilot for Apollo 14. I found him notable for his almost invisibility in memoirs of the time. In both Deke Slayton’s and Eugene Cernan’s fascinating autobiographies Ron Evans is there an accepted, uncontroversial part of the missions, without a strong personality, extremely competent – obviously the perfect man for the pilot seat of the command module America.

Adventures in the Taurus-Littrow valley

A moon landing was the payoff for all the hard-work, according to Cernan, “the ultimate dream for any pilot.” Following the tradition began by Neil Armstrong on Apollo 11, Cernan, as Commander, was first out on the moon. As he skipped around Schmitt quipped, “Hey, whose been tracking up my lunar surface?” and then stepped out onto a geologist’s paradise – the moon.

The primary objectives for Apollo 17 were: to sample lunar highland material older than the impact that formed Mare Imbrium and investigate the possibility of relatively young volcanic activity in the same vicinity. The Taurus-Littrow valley was selected with the prospects of finding highland material in the valley’s north and south walls and the possibility that several craters in the valley surrounded by dark material could be linked to volcanic activity

Cernan and Schmitt had a three-day lunar surface stay, conducting three periods of extra-vehicular activity, either moonwalking or driving around in the third Lunar Roving Vehicle. They amassed over 22 hours on the surface during these periods in which they collected lunar samples and deployed scientific instruments.

Eugene Cernan on the first EVA, suits still pristine and the Earth above his head. Evocative shot by Jack Schmitt. Photo credit NASA.

The largest haul of lunar rocks was collected by the two moon-walkers as well as deploying the Apollo lunar surface experiments package (ALSEP), a feature of all manned lunar missions. The stations ran from deployment until they were turned off on 30 September 1977 due to: budgetary considerations, the power packs could not run both the transmitter and any other instrument, and the ALSEP control room was needed for the attempt to reactivate Skylab.

They also carried out gravimeter experiments to learn about the moon’s internal structure. The gravimeter was used to obtain readings at the landing site in the immediate vicinity of the lunar module, as well as various locations on the mission’s roving routes.

Eugene Cernan next to the lunar rover vehicle. Photo credit NASA.

Meanwhile the command module also housed a series of scientific experiments. A special bay housed three experiments (as well as cameras and altimeter) for use in lunar orbit: a lunar sounder, an infrared scanning radiometer, and a far-ultraviolet spectrometer. The film canisters were recovered by Ron Evans in a spacewalk after docking with the returned lunar module.

Ron Evans on his space-walk to retrieve film canisters from the outside of the service module prior to separation of the command module and return to earth. Photo credit NASA.

Splashdown in the Pacific on December 19, 1972 brought this “first phase” of human space exploration to a close – I now wait for the second phase to begin and wonder who might it be?

Cite this article:
Orrman-Rossiter K (2012-12-18 00:03:17). Apollo 17: last men on the moon. Australian Science. Retrieved: May 19, 2024, from http://australianscience.com.au/space/apollo-17-last-men-on-the-moon/

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Who found the water on the Moon?

Kevin Orrman-Rossiter — Mon, 26 Mar 2012 07:06:39 +0000

At just over two tonnes, the second stage of an Atlas V rocket, makes for an unusual ‘kinetic probe’. Nonetheless on October 9, 2009 NASA deliberately impacted a spent Centaur rocket into the lunar south polar crater Cabeus. The target area was a permanently shadowed region within this crater. The impact, not surprisingly, ejected a spectacular plume of debris, dust and vapour.

Science experiment, observe the system, perturb it, and measure what happens

The US scientists had thrown a heavy object at the Moon. They then threw all the instruments possible to monitor the impact. The prize was a decades-long search to directly find water on the Moon.

The impact would have been majestic to watch. Picture those slow motion images of Apollo astronauts on the Moon. Hold that thought and then imagine the impact. An observer could marvel at the slow motion, low gravity, return of the dust and debris cloud to the Moon’s surface. If you could see in the infra-red, the impact flash lasts for 10 seconds. There is a cloud of debris, dust, and vapour rising. At eight seconds the the ejecta cloud is 4.5km in diameter, in the ultra-violet spectrum, the plume is 10km in diameter. At 20 seconds after impact the ejecta cloud was is at its maximum diameter of 8.5km and the plume has reduced to little less than 10km.

The observer would be watching a science experiment on a grand scale.

The observer in this experiment was neither you nor I, it was a trailing “shepherding spacecraft”. The Centaur had propelled NASA’s Lunar Reconnaissance Orbiter and Lunar Crater Observation and Sensing Satellite to the Moon. Shortly after launch the Lunar Reconnaissance Orbiter had separated to go on its own mission. Once in lunar orbit the Centaur had vented its remaining fuel. Control was then assumed, for the next four months, by the Lunar Crater Observation and Sensing Satellite as the shepherding satellite. During this next period the shepherding satellite maneuvered the Centaur to allow the Sun to bake-out residual water and volatiles. This was to ensure that no contaminant chemicals were passengers to the lunar impact site. The Centaur’s fuel was a volatile combination of liquid hydrogen and liquid oxygen, both chemicals that were to be scanned for in the impact cloud. The Lunar Crater Observation and Sensing Satellite also calibrated its instruments, then targeted the Centaur to impact with the Moon. Four months of meticulous preparation.

LCROSS spacecraft with Centaur stage, image credit NASA

The Lunar Crater Observation and Sensing Satellite carried nine instruments, including cameras, spectrometers and a radiometer. The spectrometers measured the reflected light at different wavelengths. These enabled the identification of the chemicals present in the ejected cloud.

Near-infrared absorbance attributeble to water vapour and ice, and ultraviolet emissions attributable to hydroxyl radicals (OH-) support the presence of water in the debris. The researchers determined from these observations that there was over 5%, by mass, of water ice in the lunar regolith of the impact site. Certainly this is small by terrestrial soil standards, but more substantial than most earlier estimates.

Over a year after the impact, in the October 22, 2010 issue of the journal Science, the results of this experiment were delivered to the world’s attention. This certainly marked a defining moment for lunar scientists, directly confirming the availability of water on the moon. It was however neither the first nor last word on this.

Cabeus crater LCROSS impact site, photo credit NASA

Early attempts

Since the first lunar sample were carried back to earth by Apollo astronauts in the late 1960s, scientists have operated under the presumption that the moon was entirely dry. In total 382kg of lunar material was bought to Earth by the Apollo missions astronauts and a further 0.32kg by the unmanned USSR Lunar missions. New analyses of these rocks with improved analytical techniques have made it possible to perform highly sensitive isotopic measurements on very small lunar grains. These analyses are revealing water in Apollo samples that were once thought to be dry.

Well before these new studies, scientists had been puzzling about why more water was not seen on the moon. It was thought that volatile materials, such as water, could be accumulating at the moon’s permanently shaded polar regions. Here they could be trapped for geological periods of time without significant loss. The in 1998, the orbiting Lunar Prospector spacecraft measured the the abundance of elements on the moon’s surface using neutron spectroscopy. This provided compelling evidence for enhanced hydrogen concentrations, and by inference water, at both of the lunar poles.

In 1999 the Cassini spacecraft flew by the moon on its way to Saturn. It turned its Visual and Infrared Mapping Spectrometer to the moon. By measuring the surface reflectance of light from the moon scientists found absorption attributed to hydroxyl and water on the sunlit surface of the moon. These results were not published until 10 years later, in October 2009. The reason was renewed interest in water on the moon.

On October 22, 2008 Chandrayaan-1 was launched on a lunar mission by the Indian Space Research Organisation. One of its major scientific missions was to look for water on the moon. It had three different instruments ready to make 2008-10 an interesting period for lunar water exploration.

Chandrayaan-1, India’s lunar water finder

The Chandrayaan-1 story is told in detail elsewhere. Here I intend to showcase the marvelous outcome of Chandrayaan-1’s water finding experiments. Perhaps the most exciting of all these was one of the simplest. This was the CHandra’s Altitudinal Composition Explorer (CHACE) on board the Moon Impact Probe.

On November 14 2008 (the birthday of the late Pandit Jawaharlal Nehru, India’s 1st Prime Minister) the Moon Impact Probe became the first Indian built object to reach the surface of the Moon. The probe was a 34kg box-shaped object containing a video image system, radar altimeter, and The CHACE mass spectrometer.

Symbolically the Indian tricolour was painted on three sides of the Moon Impact Probe. This enables India to also lay claim to having the “Indian tricolour placed on the Moon”. Needless to say that “placing” in this case was a hard landing in the Moon’s south polar region near the Shackleton crater, flying over the Malapert mountain en route.

The CHACE mass spectrometer took 650 spectra of the tenuous lunar atmosphere during its 1487 second, 98km, plunge to the lunar surface. Tenuous is right the atmosphere even on the sunlit side is only 7/10,000,000,000th of the Earth’s atmosphere.

The mass spectrometer was tuned to look find water and direct evidence of water it did find. The team leader of the experiment, Dr S M Ahmed, remembers, “We all were jumping when we saw water was literally pouring out of our instrument

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