Cloud Observatory, Lunar Reflectance Craft in NASA Earth Venture Race

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WASHINGTON — A moon-watching small-satellite and a trio of formation-flying cloud monitoring sensors are among the early candidates vying for a shot at $150 million in funding under a NASA Earth Venture competition set to begin this summer.

Details about the proposed missions appeared in separate notices posted to a NASA procurement website in March.

The lunar observation concept, Arcstone, originated at NASA’s Langley Research Center in Hampton, Virginia. The three-satellite Cloud Observation for Updraft Determination (CLOUD) came from the Glenn Research Center near Cleveland.

Arcstone is led by principal investigator Constantine Lukashin, a Langley research scientist. The mission will attempt to create the most accurate measurements yet of the lunar irradiance spectrum — the different wavelengths of sunlight reflected off the moon’s surface. This could lead to more precise calibration of Earth observing instruments, according to Langley spokesman Michael Finneran.

To accomplish its mission, Arcstone will have to observe the moon daily for about three years using a compact spectrometer installed on a small, low-Earth-orbiting satellite weighing no more than 50 kilograms, Finneran told SpaceNews.

“The Moon is considered, theoretically, as an excellent exoatmospheric calibration source,” Finneran wrote in a March 11 email. That is because the reflective properties of the lunar surface remain more or less static, providing an essentially unchanging light source that, once accurately measured, could be used as a reference point for adjusting color-sensitive instruments aimed at Earth.

Once the lunar irradiance spectrum is accurately measured, the results could be used to retroactively color-correct data already beamed down from operational Earth observing satellites, and to recalibrate the instruments on those spacecraft. Future Earth science missions would also benefit, Finneran said.

Glenn, meanwhile, is proposing a larger build: three 180-kilogram CLOUD satellites that could launch as a secondary payload with a host satellite weighing no more than 3,000 kilograms.

“The main objective of the CLOUD mission is to address climate change uncertainties and enhance weather prediction,” NASA spokesman Frank Jennings wrote in an April 1 email.

CLOUD’s principal investigator is John Mecikalski, a professor in the Atmospheric Science Department at the University of Alabama in Huntsville, Alabama. The three-satellite observatory would spend at least a year in an 824-kilometer, near-polar orbit inclined at 98.7 degrees, monitoring clouds in the visible spectrum at a 30-meter resolution.

The competition for the next Earth Venture mission was set to begin between April 1 and June 30, according to the notice of opportunity for CLOUD posted by Glenn March 11. NASA is expected to announce a winner in early 2016, with launch taking place in 2021. The Earth Venture cost cap of $150 million does not include the price of a launch.

The Goddard Spaceflight Center in Greenbelt, Maryland, has also expressed interest in the latest round of Earth Venture funding.

The Greenbelt, Maryland-based center in November said it is planning an Earth Venture hosted payload that would weigh 92-108 kilograms, occupy roughly 1 cubic meter, draw 81-100 watts of power and require a data downlink rate of no more than 9 megabits per second.

Goddard wants to partner with either a satellite manufacturer or a satellite owner-operator to put its Earth Venture payload aboard a satellite bound for a geostationary orbit between 50 and 100 degrees west, locations that would provide coverage of parts of North and South America.

Arcstone, CLOUD and the Goddard proposal will square off with any other competitors that emerge in the second Earth Science Venture-class competition. The first Earth Venture competition was won in 2011 by the Cyclone Global Navigation Satellite System (CYGNSS), which is set to launch in October 2016. The two-year mission aims to improve hurricane forecasting by using a constellation of eight nanosatellites to observe ocean surface winds during tropical storms and hurricanes.

Chris Ruf, a professor of atmospheric science and electrical engineering at the University of Michigan, is principal investigator for CYGNSS. The Southwest Research Institute in San Antonio is building the nanosats, while Sierra Nevada Corp. Space Systems of Louisville, Colorado, will provide the deployment canister in which the small spacecraft will launch.  Surrey Satellite Technology, Guildford, England, will provide the mission’s primary instrument, the Delay Doppler Mapping Instrument.