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s on mm Co ia ed im ik W e rc u so e g a im r; u to ia V c u L f o y s te r u o c e g a m Space exploration:I the return to the Moon

Have you ever looked up at the Moon in a clear night sky and wondered about the very few people who have walked on its surface? What did we learn, and what are we still unsure about? When might humans return to the Moon? Adam Baker investigates.

General science

n 1969, Neil Armstrong and Buzz although we can study the Earth The space exploration IAldrin became the first humans to more easily, its surface has been race of the 1960s was a walk on the surface of another astro- altered by weathering, whereas the very exciting period and nomical body: the Moon. Over the surface of the Moon has remained important in the develop- next three years, ten more American more or less unchanged since its ment of a number of tech- astronauts landed on the Moon as formation. nologies; the Moon land- part of the USA’s Apollo programme. · The overall chemical composition ings were a major high- Since then – nearly 40 years ago – and internal structure of the Moon. light. After a gap of sever- there have been no further manned This will start to tell us how the al decades, people are missions to the Moon. Why is that? Moon originated, and whether it again planning to explore And when might people return to the formed from bits of Earth debris, as the Moon – this article Moon? some theories claim. considers how and why. In the 1960s and 70s, the Apollo · Whether resources such as water The article could be used programme and the unmanned are available on the Moon, which as the starting point of dis- Russian Luna and US Surveyor mis- would enable astronauts to use the cussions in science or sions concentrated on the surface of Moon as a base for exploring other technology lessons, for the near side of the Moon and left planets. example on the history of many key questions unanswered, in Today, space technology is seen as science. It could also be particular: mostly addressing problems on Earth, used in science clubs or · The age of the Moon and how this such as climate change; the European similar activities. is linked to the age of the rest of Space Agency (ESA), for example, has Eric Deeson, UK the Solar System. The rocky surface launched many satellites to observe REVIEW of the Moon is key to this research: the Earth’s atmosphere, oceans and

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Cutting-edge science

The locations of spacecraft that have landed on the moon. Green trian- gles represent Apollo missions, yellow are NASA Surveyor missions, and red are Russian Luna spacecraft

Smart-1, ESA’s lunar orbiter mission

Image courtesy of National Space Science Data Center / NASA’s Goddard Space Flight Center Image courtesy of ESA

ice capsw1. Nonetheless, after years of strategyw4 was agreed between 14 space Little data from Chang’e-1 has been inaction in lunar exploration, the past agencies and organisations, encom- released to the international commu- decade has again seen many countries passing the US vision, as well as nity, however. sending missions to the Moon. space exploration plans from other In April 2008, the Indian In 2003, ESA sent the robotic countries such as the UKw5. Chandrayaan-1 orbiter was launched (unmanned) Smart-1 missionw2 to September 2007 saw the launch of to address many of the same ques- orbit the Moon, to test technology for the Japanese Kaguya orbiter mission tions as the Kaguya orbiter. sending missions accurately beyond (originally known as Selene). While Additionally, Chandrayaan-1 carried Earth’s orbit, and to conduct basic sci- orbiting the Moon’s surface, it a radar instrument, allowing scientists ence such as X-ray observations of the searched (unsuccessfully) for water to peer into dark craters near the Moon. Shortly afterwards, ESA also on the lunar surface, measured the lunar poles for the first time. These launched the Mars Express mission, strength of the lunar gravitational radar measurements suggested that its first mission to orbit another plan- field using a small satellite, and stud- water ice was present at the lunar et, with a package of scientific instru- ied the chemistry of the lunar surface. south pole. This was confirmed in ments. These missions marked the Kaguya also imaged the lunar surface 2009 when the US LRO orbiter fired a reawakening of interest in space in visible wavelengths, generated rocket, the LCROSS impactor, into a exploration. maps of much of the surface, and south pole crater: instruments on the In the USA in 2004, President George measured the radiation in orbit to orbiter detected evidence of water ice W. Bush directed NASA to return to assess the risk to future astronauts. in the particles that were thrown into the Moon and build a long-term out- The Chinese orbiter Chang’e-1, space by the crashw6, w7. Data from the post on the lunar surface as part of launched a month later, also studied LRO orbiter even showed where – 37 his vision for space explorationw3. the topography and chemistry of the years before – a Russian lunar rover Subsequently, a global exploration lunar surface and searched for water. had come to restw8.

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Image courtesy of NASA Kennedy Space Center (NASA-KSC) Image courtesy of NASA

Launch of Apollo 11 in 1969

This is one of the few photographs show- ing Neil Armstrong on the Moon (he car- ried the camera most of the time). He is reflected in Buzz Aldrin's visor

build bases and transmitting the data directly back to Earth via radio links. Already, such missions are being planned. China and India intend to follow their recent orbiter missions with robotic landers (Chang’e-2 and Chandrayaan-2, respectively). To build on these and other lunar mis- sions and to cover a larger portion of the unexplored lunar surface, the UK is developing small, low-cost space- craft. With their automated guidance systems and miniaturised instruments, These recent missions, therefore, missions, orbiting far above the these spacecraft would enable regular, have gone some way to addressing Moon’s surface, cannot answer. What, inexpensive, small missions to the the questions left unanswered in the for example, is the effect of lunar dust Moon – starting as early as 2014. With 1970s, providing information about on people, vehicles and telescopes? the support of ESA, other European the chemical composition of more of Can we survive on the Moon for peri- nations are also studying advanced the Moon’s surface, and hinting at the ods as long as several weeks? What lunar landersw9. These will carry a presence of water and other resources new technology, such as power wide range of technologies and can that might be found at the cold, dark sources and thermal insulation, is test systems suitable for carrying astro- south pole (below 100 K). More infor- needed to help astronauts survive nauts and for future Mars expeditions, mation is still to come – some of the comfortably when working in the but will be larger and more costly, and extensive maps generated by Japanese, dark, extremely cold lunar polar are not fully funded yet. Chinese, Indian and American orbiters craters? Although the US vision for space are still being processed. The answers to these questions will exploration – with a manned lunar However, to fully understand the require landers – robots to land on the base by 2020 – sounds exciting, nature of the Moon and its environ- surface of the Moon and directly NASA and the US government have ment – and potentially to prepare for measure the properties of dust, rock recently decided that their plans are people to visit and stay safely on the and the lunar environment (such as unaffordable. Instead, it will be robot- Moon for long periods, making astro- moonquakes) over extended periods. ic lunar missions that characterise the nomical observations, investigating Unlike the unmanned missions of the lunar environment and map available the lunar geology, preparing for more 1960s and 70s, future lander missions resources, providing a logical, faster distant space exploration or even would need to investigate the entire and more affordable route to a sus- mining lunar resources – we need lunar surface, carrying out scientific tained presence on our nearest neigh- information that even these recent studies, seeking the best places to bour. Although it will probably be

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Cutting-edge science

Image courtesy of NASA Jet Propulsion Laboratory (NASA-JPL) Image courtesy of SSTL Image courtesy of SSTL

The far side of the Moon, a view of the The UK’s planned MoonLITE orbiter The UK’s planned MoonRaker lander lunar surface not possible from Earth, has four penetrators – small daughter would give accurate indications of the taken from the Galileo spacecraft in spacecraft to be fired into the Moon’s age of the Moon, sampling regions which 1990 surface no mission has yet visited

some time before the 13th human water on moon’, see The Guardian watch?v=oXxGE4tBBEA lands on the Moon, robotic missions website (www.guardian.co.uk) or NASA’s archive for lunar mission are key to bringing that day ever clos- use the direct link: data: http://nssdc.gsfc.nasa.gov/ er. This is a lasting legacy of Apollo. http://tinyurl.com/ylmb6pm planetary/lunar w7 – For more information about the To mark the 40th anniversary of the Reference LRO mission, see: Moon landings, BBC Radio 4 pre- Hodge R (2006) The sky’s the limit. http://lunar.gsfc.nasa.gov sented the story of the British Science in School 1: 70-71. w8 – To learn more about the recently MoonLITE project and the lunar www.scienceinschool.org/2006/ discovered Russian lunar rover, see ambitions and achievements of the issue1/baker the Science Daily website other space-exploring nations. See: www.bbc.co.uk/programmes/b00lnycv Web references (www.sciencedaily.com) or use the direct link: If you enjoyed this article, you might w1 – To learn more about the http://tinyurl.com/yfbzjcv like to browse all the Science in European Space Agency’s earth School articles about space science. observation programme, including w9 – ESA is inviting industry to See: www.scienceinschool.org/space the CryoSat-2 ice satellite to study submit proposals for a lunar lander the effects of global warming, see: mission. For more details, see the www.esa.int/esaEO ESA website (www.esa.int) or use the direct link: Adam Baker works for Virgin w2 – To learn more about ESA’s http://tinyurl.com/2utzaq7 Galactic as their safety manager, in Smart-1 mission, see: charge of assessing and ensuring the www.esa.int/SPECIALS/SMART-1 w10 – Surrey Satellite Technology specialises in designing, building safety of future sub-orbital passenger w3 – To learn more about the US flights. He wrote this article while vision for space exploration, see: and launching small satellites. See: www.sstl.co.uk working at Surrey Satellite http://history.nasa.gov/sep.htm Technologyw10, which defined the w4 – For more information about the Resources MoonLITE and MoonRaker missions. global exploration strategy, see: Adam studied materials science at www.globalspaceexploration.org For more information about the the University of Oxford, UK, where Apollo programme, see: w5 – The 2007 report of the UK space he then completed a PhD on compos- exploration working group can be Flightglobal’s website devoted to ite materials for jet engines. During his downloaded from the UK Space Apollo missions: PhD, he built rocket engines as a Agency website (www.bnsc.gov.uk) www.flightglobal.com/page/ hobby, which is how he came to work or via the direct link: Apollo-40th-Anniversary for Surrey Satellite Technology and http://tinyurl.com/3xe8vr7 A video commemorating the 40th then Virgin Galactic. For more infor- w6 – To read the article ‘NASA ‘ecsta- anniversary of the first walk on the mation about Adam, see Hodge (2006). tic’ after LCROSS impact reveals Moon: www.youtube.com/

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