NASA will soon launch a one-of-a-kind instrument, called Arcstone, to improve the quality of data from Earth-viewing sensors in orbit. In this technology demonstration, the mission will measure sunlight reflected from the Moon— a technique called lunar calibration. Such measurements of lunar spectral reflectance can ultimately be used to set a high-accuracy, universal standard for use across the international scientific community and commercial space industry.
To ensure satellite and airborne sensors are working properly, researchers calibrate them by comparing the sensor measurements against a known standard measurement. Arcstone will be the first mission exclusively dedicated to measuring lunar reflectance from space as a way to calibrate and improve science data collected by Earth-viewing, in-orbit instruments.
“One of the most challenging tasks in remote sensing from space is achieving required instrument calibration accuracy on-orbit,” said Constantine Lukashin, principal investigator for the Arcstone mission and physical scientist at NASA’s Langley Research Center in Hampton, Virginia. “The Moon is an excellent and available calibration source beyond Earth’s atmosphere. The light reflected off the Moon is extremely stable and measurable at a very high level of detail. Arcstone’s goal is to improve the accuracy of lunar calibration to increase the quality of spaceborne remote sensing data products for generations to come.”
Across its planned six-month mission, Arcstone will use a spectrometer — a scientific instrument that measures and analyzes light by separating it into its constituent wavelengths, or spectrum — to measure lunar spectral reflectance. Expected to launch in late June as a rideshare on a small CubeSat, Arcstone will begin collecting data, a milestone called first light, approximately three weeks after reaching orbit.
“The mission demonstrates a new, more cost-efficient instrument design, hardware performance, operations, and data processing to achieve high-accuracy reference measurements of lunar spectral reflectance,” said Lukashin.
Measurements of lunar reflectance taken from Earth’s surface can be affected by interference from the atmosphere, which