NASA to launch six small satellites to monitor and study tropical cyclones

NASA launches the first two of six small satellites no earlier than June 12, to study the formation and development of tropical cyclones almost every hour, about four to six times more often than is possible with current satellites. This is the first of three CubeSat launches for NASA’s time-resolved observations of precipitation pattern and storm intensity with a Constellation of Smallsats (TROPICS) mission. The remaining satellites will be placed into orbit in two subsequent launches this year. If successful, the TROPICS satellites will be spread over three orbital planes to more frequently cover the globe.

“TROPICS will give us very frequent views of tropical cyclones, giving insight into their formation, intensification and interactions with their environment and providing critical data for storm monitoring and forecasting,” said Scott Braun, meteorologist. researcher at NASA’s Goddard Space Flight Center in Greenbelt. , Maryland.

Collectively, the weather satellite currently in low Earth orbit – as NOAA-20, the joint NASA and National Oceanic and Atmospheric Administration Suomi NPP powerhouse Satellite, and others from NASA partners – revisit a storm once every four to six hours. “So we miss a lot of what’s going on in the storm,” said Bill Blackwell, principal investigator of the TROPICS mission and researcher at the Massachusetts Institute of Technology Lincoln Laboratory in Lexington, Massachusetts. The TROPICS constellation will provide scientists with more frequent updates, supplementing data collected by existing low Earth orbit weather satellites and allowing scientists to see every storm from start to finish.

Three launches will place the six paired satellites into three slightly different low Earth orbits, all at an angle of nearly 30 degrees above the equator. This will maximize the time the satellites spend over the part of Earth where most tropical cyclones form – a horizontal band stretching from the mid-Atlantic region of the United States to the southern coast of Australia. , roughly between 38 degrees north and south latitudes. Ideally, one of the TROPICS satellites will pass over a given area in this band approximately once per hour.

All matter, including water vapor, oxygen, and clouds in the atmosphere, emit energy in the form of heat and light, a phenomenon known as Planck’s law. Each of the TROPICS satellites has an instrument called a microwave radiometer that measures these atmospheric emissions. The sensors make passive measurements similar to those made by Advanced Technology Microwave Sounder (ATMS) instruments on today’s weather satellites in low Earth orbit.

The microwave radiometer on board each TROPICS satellite measures microwave frequencies ranging from about 90 to 205 gigahertz. These frequencies tell scientists about the temperature, precipitation, humidity and other characteristics of the storm and the surrounding atmosphere. The amount of heat and light – or radiation – at these frequencies comes from different altitudes, allowing TROPICS satellites to create three-dimensional images of the cyclone environment. The frequencies used by TROPICS are also very sensitive to ice and cloud characteristics, which will help meteorologists study how tropical cyclones develop and intensify. However, TROPICS frequencies are less sensitive to temperature and humidity below the clouds, something the ATMS instruments aboard the NOAA-20 and Suomi-NPP satellites excel at. Together, data from TROPICS and current weather satellites will help scientists refine their understanding of tropical cyclones.

“With the TROPICS constellation, we will have much more frequent sightings of tropical cyclones, and in wavelengths that can help us understand the thermodynamic structure in the eye and surrounding the storm,” Blackwell said. .

If all goes as planned, the six TROPICS satellites will join the TROPICS Pathfinder satellite, a proof-of-concept CubeSat launched in June 2021. Since then, the pathfinder has captured images of several tropical cyclones, such as Hurricane Ida over the United States, Cyclone Batsirai over Madagascar, and Super Typhoon Mindulle over eastern Japan. The Pathfinder satellite also provided the TROPICS research team with the opportunity to fine-tune the satellites’ software and operational procedures prior to the constellation launch. In addition, the pathfinder has already been calibrated and can be used as a calibration reference for the rest of the TROPICS satellites. This would help the TROPICS CubeSats start producing useful data quickly.

“The TROPICS team is very excited to bring the constellation into service, especially after the success of the scout,” said Blackwell.