Moon's surface, stable as one

The lunar surface becomes a "calibration tool"

Introduction: While the Earth's surface is highly variable, the Moon's surface is more stable. The Moon's visual uniformity offers the possibility of calibration and positioning tools.

The Moon's relatively static surface is an ideal candidate for the calibration of Earth observation instruments.

Things are constantly changing. This daunting idea has proven to be a correct conclusion at all times, but when it comes to calibrating instruments that observe the Earth's surface, a visually consistent object is needed, and that is the Moon. With the Moon, instruments can ensure that the environmental data collected from the Earth is of superior quality and more reliable.

While the Earth's surface continues to evolve, the Moon's surface has remained unchanged for millions of years. Except for the occasional meteoroid impact, the Moon's surface has remained virtually unchanged, making it a perfect candidate for the configuration of these instruments. A project led by the European Space Agency (SEA) is now planning to improve the Moon's utility.

For this reason, a group of scientists went to the slopes of Mount Tide on the Spanish island of Stiffener to observe the Moon, avoiding clouds and airborne dust. They installed an instrument on Mount Tide specifically designed to measure changes in the moonlight at night to improve the accuracy of future lunar calibration efforts.

"Space agencies around the world use the Moon as a calibration for evaluating, monitoring, and monitoring Earth's optical observation instruments," explained Mark Bounty, who oversaw the project. "These instruments are carefully calibrated before launch, but in space, due to radiation, lens contamination, or mechanical changes, their performance may gradually drift.

"We need to be sure that the changes in the light received from Earth represent real changes on the ground, not changes in the instruments. Therefore, we need a calibration target that represents an unchanging, stable source to identify any performance drift in space instrument measurements."

Some missions use in-house calibration equipment, and others use relatively unchanging terrestrial features, such as plains in the desert, oceans, or salt flats, to accomplish this configuration. In this SEA-led project, researchers can simulate radiation from these target things. But the problem with calibrating from Earth is that the land still changes over time.

"The lunar surface is invariant compared to anywhere on Earth," Mark added, "so many Earth observation missions use the moon to monitor the stability of their calibration, whether from LEO or geosynchronous orbit."

"The main problem is that the moon we see is not always the same, no matter where we look from. It does not have a neat, circular orbit around the Earth, nor does the Earth have a perfectly circular orbit as it revolves around the Sun. We don't always see the same side of the moon every 28 days of its cycle: Sometimes we see more on the sides or top, and that's what we know as lunar libation."

"It takes 18 years for the moon to return to its present appearance."

He said: "Our goal is to look at the entire lunar surface over two years to be able to build a more accurate model of the lunar radiation. The current best modeling has a 10 percent uncertainty; we hope to get that down to about 2 percent."

A solar photometer is now housed on Mount Thaddeus. This is similar to the global network of photometers that are measuring particles in the atmosphere. The difference with this instrument is that it is carefully designed to work at night and measure the intensity of moonlight.

Thanks to the support of the SEA Activity Initiative, the project is being handled by a consortium that includes the National Physical Laboratory of the United Kingdom, the University of Validation of Spain, and Vito (Flanders Institute of Technology) of Belgium.

"A lunar calibration meeting was held last year with participants from NASA, the National Oceanic and Atmospheric Administration (NORA), the Center national desuetude spatial (ONES), the Japan Aerospace Exploration Agency (AJAX), and China," Mark added.

"There are a lot of people who are excited about this project - the U.S. and Chinese efforts, for example, say it all. Because success will allow us to co-calibrate references about past, present, and future optical observing missions, making the data easier to cross-compare and enriching our overall understanding of the Earth's environment."

"We expect the improved model to be operational within a decade."