2013 was a fantastic year for Moon missions, providing a new orbiter, lander and even a rover to take a fresh look at the lunar surface and what lies below. These instruments are exploring both previously studied and completely new areas of lunar science, including a detailed in situ analysis of the chemical composition of the regolith, the characteristics and origin of the elusive lunar atmosphere, and even some experiments targeting the Earth! The next few years are also set to be some exciting ones with plenty of upcoming missions from around the world. The following is a brief overview of what the brand new lunar companions are up to, what is coming up in the near future, and how all of this could enhance our current understanding of the Earth’s natural satellite.
As you’ve probably heard, China recently launched their Chang’e 3 mission in December 2013, which safely landed on the Moon and immediately deployed its Jade Rabbit rover to begin exploring the surface. Just a few of months prior to this, in September, NASA sent its Lunar Atmosphere and Dust Environment Explorer (LADEE) mission, which is currently in orbit collecting data. These two missions joined three other operational lunar satellites: ex-Earth satellites ARTEMIS P1 + P2, and the Lunar Reconnaissance Orbiter (LRO) which supplies Moon Zoo with all its high resolution images.
LADEE represents the fifth NASA mission to the Moon since 2009 and is after some interesting new data regarding the tenuous lunar atmosphere. The role of dust transport through the Moon’s exosphere is still very poorly understood, so this satellite is designed to study the process in detail as well as analyse general atmospheric properties. The payload contains a UV and visible spectrometer to study the composition of dust grains, a neutral mass spectrometer to search for noble gases present, and a lunar dust experiment to measure grain impacts at different altitudes. Interestingly, the module also carries a laser communication experiment, which is investigating the viability of using lasers to beam back data to Earth. This technology could be incredibly valuable for future missions farther into space as high volumes of data can be transmitted more efficiently than using radio waves.
So far the mission has already detected atmospheric helium, sodium, neon, potassium and argon-40, as well as confirming a lunar dust exosphere which before was only predicted. The instrument, orbiting between 20 and 150 km, has detected very few dust grains at high altitudes, but this value significantly increased as it descended. LADEE has also measured a few bursts of dust, which are thought to be a consequence of flying through ejecta caused from the impacts of nearby meteorites into the lunar regolith.
Just a few months into LADEE’s mission, the Chinese landed their first craft on another planetary body. The touchdown of Chang’e 3 came more than 40 years after the US sent the first astronauts to walk upon the lunar surface; nonetheless, this does not diminish the mission’s significance at all. The craft, testing out some really exciting new technology and equipment, will be transferring its findings to manned or unmanned missions in the future, heading for the Moon, Mercury or Mars!
The primary mission objective of Chang’e 3 is to analyse the lunar soil composition in situ in much more detail than previously achieved. Its rover, Yutu, or ‘Jade Rabbit’ in English, thus aims to further our understanding of the Moon’s – and in turn the Earth’s – history. At just 1.5 m across, Jade Rabbit carries ground-penetrating radar, cameras, a telescope and spectroscopic instruments to help achieve this goal.
Chang’e 3’s landing destination on the north edge of Mare Imbrium is a different site to those previously visited by the US and USSR missions, with emphasis on how the surface and sub-surface vary from one location to another. Over the course of the mission, it is likely that Moon Zoo will also begin a survey of this area using LRO data, so that participants can help build up a more comprehensive understanding of the site.
Alongside analysing the concentration of elements such as titanium, aluminium, iron, potassium and sodium in the surface materials, there will also be a focus on non-geology related science experiments. On the static landing module one investigation will use an extreme UV camera to monitor the structure and dynamics of Earth’s plamasphere, a region of dense, cold, highly ionized particles surrounding the Earth. A near-UV telescope will also observe stars and galaxies outside the Earth’s opaque (at these wavelengths) atmosphere. As the Moon provides a platform for long, uninterrupted observations, this experiment might inform us whether it can be used for future imaging any more effectively than a telescope in orbital space.
So, these are the data the current instruments are after, but what else do the next few years have in store? Well, in late 2014 NASA’s Orion spacecraft is heading for a flight test to orbit around the Earth with a manned crew. This will be the farthest distance from Earth astronauts have flown since the Apollo 17 mission in 1972. Also due to launch in the next few years are the Chandrayaan-2 orbiter and lander, which will mark India’s second lunar exploration mission and first touchdown. However, originally scheduled for 2015, it was revealed last week to be postponed until 2016-2017.
In fact, it’s probable that the next set of missions to the Moon will not be coming from nation states, but from private companies competing for the Google Lunar XPRIZE (GLXP). The competition, announced in 2007, has opened up a global space race with a first prize award of $20 million. The second craft to reach the Moon will receive a prize of $5 million, and an extra $5 million is on offer in bonuses to any team that achieves certain goals first. The aim of the GLXP is to inspire and encourage humanity to accomplish significant exploration feats and, in doing so, demonstrate that we are within an age where space exploration is not a monopoly of national governments.
With teams in the running from all over the globe it’s hard to tell where the fourth lunar rover will originate from. However, with a closing date of December 31st 2015 and 18 entrants still in the running, I think it is safe to expect a number of exciting new lunar launches in the next couple of years!
The Moon is seriously old and our objective here at Moon Zoo is to study its surface with the time and detail that cannot be afforded by a small team of scientists. Earth’s closest neighbour and only natural satellite represents the largest and brightest object in the sky second to the Sun, and plays a crucial physical role to life here on Earth. But as the only other body to have been walked upon by man, what do we actually know about the Moon? Why is it so important to continue to study? And what can Moon Zoo’s 47,000 participants do to help?
One of the main focusses at Moon Zoo is to examine the distribution of craters in various regions in terms of their size and frequency. By determining this relationship, we can then independently estimate surface ages of different areas that have been examined by the community. Discerning these surface ages is key to understanding the history of the early Solar System, as the Moon is thought to have formed just 30-50 million years after its birth 4.5 billion years ago. The colossal impact of the Mars-sized body, Theia, into the early Earth stripped the outermost layer of our planet and returned it to a molten state, whilst the ejecta was captured in orbit and accreted to form the Moon. Although not perfect, this hypothesis explains the relatively small size of the Moon’s core and overall lower density, since it coalesced mostly from lighter crustal material. Whilst the Moon’s internal structure is differentiated into a core, mantle and crust in a similar way to the Earth’s, its rapid cooling saw tectonic and volcanic activity cease around 3.5 billion years ago. The combination of the Moon’s inactive geology and highly tenuous atmosphere has enabled its surface to become one of the most ancient, and well-preserved in the Solar System. From this almost perfectly kept record, we are not only able to look into the Moon’s past, but also unravel some of the mysteries surrounding the Earth’s history, the early Sun, and previous Solar System environments.
On Earth, tectonic, volcanic, and weathering activity has destroyed much of its early record, which is why we look to the Moon to understand our own history. We use observations of different surface features and lunar samples to date particular regions, which can help indicate events that occurred in the inner Solar System. This can, for example, be used to date periods of heavy bombardment from asteroids, which enables us to investigate the frequency of such events in Earth’s history. The samples obtained from the Moon originate from its outermost layer, known as the regolith, which is comprised of fine dust formed by impact processes. The Moon’s practically vacuous atmosphere does little to interfere with this layer, so it is able to preserve the impact fragments and provide insight into the composition and origin of colliding bodies. The regolith also incorporates particles from the solar wind, which allows us to examine how the Sun has changed over its lifetime.
Moon Zoo is helping to uncover the lunar geological evolution by analysing high-resolution images from NASA’s Lunar Reconnaissance Orbiter (LRO), in order to expand our knowledge of past impact, tectonic and volcanic activity on the Moon. Alongside crater counting, the other current primary focus is the identification of boulders, which can indicate depth of unconsolidated material. Another outcome of this search will be the production of boulder-density maps, which can be used for future lunar missions to indicate safe (or very hazardous!) landing sites.
To date, the Moon Zoo community has already made over 3.5 million visual classifications with images from LRO, alongside many unusual geological features; the project has also been very successful in identifying spacecraft debris, rover tracks and even astronaut footprints! Data already gathered from the work of Moon Zoo participants on the Apollo 17 landing site are well on their way to producing the first comprehensive paper showing these results, which is scheduled for submission shortly. The current Apollo 12 landing site has also received a great deal of interest and will soon be drawing to a close for full analyses by the Moon Zoo science team. The next step will be analysing an entirely new data set, which will most likely delve into the rare maria on the more mysterious dark side of the Moon.
There is still a great deal more to understand about our planet’s closest relative and the clues it holds to the history of the bodies around it. Until the next stage of the project is launched, we implore you to keep clicking and help demonstrate the strong impact of citizen science on lunar research!