On 26 October, Nasa made an important announcement on the discovery of water molecules on the sunlit surface of the Moon. So far, the only presence of water on the lunar surface was known to be limited to the cold, shadowed places of the Moon.
But using the SOFIA (Stratospheric Observatory for Infrared Astronomy ) observatory, Nasa researchers detected water molecules (H2O) in the Clavius Crater, one of the largest craters that can be seen from Earth and located in the Moon’s southern hemisphere. According to an official release from Nasa, data from this location revealed water in concentrations of 100 to 412 parts per million – that’s roughly equivalent to a 12-ounce bottle of water – trapped in a cubic meter of soil spread across the lunar surface. These results were also published in the latest issue of Nature Astronomy. Previous observations of the Moon’s surface did detect some form of hydrogen, but were unable to distinguish between water and hydroxyl (OH).
During an official press call on the announcement, Nasa researchers and project scientists said that whether the water that the SOFIA observatory found was easily accessible for use as a resource during future lunar missions remains to be determined. There’s still tonnes of research that needs to be done. This includes upcoming missions to the lunar surface that will search for water ice.
This development, however, brings focus on one key question: what makes water such a precious resource to have in space? “Water is a valuable resource, for both scientific purposes and for use by our explorers,” Jacob Bleacher, chief exploration scientist for NASA’s Human Exploration and Operations Mission Directorate, was quoted in an official Nasa statement. “If we can use the resources at the Moon, then we can carry less water and more equipment to help enable new scientific discoveries,” Bleacher adds.
For context, up to 80% of the water on even the International Space Station is recycled for astronauts to use and re-use. Simply put: ferrying water to space from earth is easier said than done. It is a precious commodity in space. “It’s difficult to carry because water is bulky. Even in a frozen form, it is required to be kept at a certain temperature. In liquid form, it is a very bulky, volume-consuming material,” says Siddharth Pandey, head of the Centre of Excellence in Astrobiology, Amity University, Mumbai. “It’s not the most preferred option (during space missions) to carry from earth. The cost of a mission and technical requirements also go up,” he adds.
Pandey explains that apart from consumption purposes, water can also be used to make rocket fuel. Split water into hydrogen and oxygen, liquefy them and you get rocket propellant. “It’s very economical. When you burn oxygen and hydrogen, the amount of energy that is released is the most efficient and cleanest form,” he adds.
Writing in The World’s Water 2002-2003, the third volume in the The World’s Water book series published by the Pacific Institute, Elizabeth L. Chalecki explains how “in situ water could yield oxygen for a breathable atmosphere and hydrogen for rocket fuel, making water not only biologically necessary but also economically desirable.” These “off-world sources of fuel”, Chalecki writes, would make space travel much more productive by allowing spacecraft to expand their payload weight. “In addition, launching rockets from the Moon rather than Earth would extend the range of future missions,” she adds.
“Water’s importance arises primarily in terms of sustaining life,” says Aloke Kumar, assistant professor at the department of mechanical engineering, Indian Institute of Science (IISc), Bengaluru. Kumar is well-versed with the idea of lunar resources. In August this year, Kumar, along with a team of researchers at IISc, published the results of a sustainable process for making brick-like structures that could be used to assemble habitats on the Moon. “We are now in an age where we are actively starting to think about human settlements on the Moon and Mars. Since we are trying to do that, we also have to worry about how we will sustain these settlements,” he adds.
Nasa’s recent announcement underlines the core belief of space exploration: the idea is to not just expand life beyond Earth, but also search for it beyond Earth. In her recent book The Search for Life on Mars, author Elizabeth Howell sums up the role of water in the grand scheme of things. “If we can’t look for life directly, then searching out water is the next best thing.”