A very small instrument with a big job ahead: measure all of the Earth-directed energy coming from the Sun and help scientists understand how that energy affects extreme, variable weather. climate and other global forces of our planet.
About the size of the shoebox or game console, Compact total radiation monitor (CTIM) is the smallest satellite ever sent to observe the total solar energy received by the Earth from the Sun – also known as “total solar irradiance”.
Credit: NASA/Willaman Creative
Total solar irradiance is a major component of the Earth’s radiation budget, which tracks the balance between incoming and outgoing solar energy. An increase in greenhouse gas emissions from human activities, such as burning fossil fuels, increases the amount of solar energy in the Earth’s atmosphere.
That increased energy raises global temperatures and changes Earth’s climate, which in turn drives things like sea level rise and severe weather.
“So far, the dominant energy source has been the mainstay of energy,” said Dave Harber, a senior research fellow at the University of Colorado, Boulder, Laboratory for Atmospheric and Space Physics (LASP) and CTIM’s principal investigator. with Earth’s climate from the Sun. “This is an important input to predictive models that predict how Earth’s climate might change over time.”
NASA missions like Earth Radiation Budget Test and NASA tools like CERES has allowed climate scientists to maintain an unbroken record of total solar irradiance spanning 40 years. This allowed the researchers to rule out increased solar energy as the culprit for climate change and to recognize the role of greenhouse gases in global warming.
Ensuring that records remain unbroken is paramount to Earth scientists. With an unbroken record of total solar irradiance, researchers were able to detect small fluctuations in the amount of solar radiation received by the Earth during solar cycleas well as highlighting the impact of greenhouse gas emissions on the Earth’s climate.
For example, last year, researchers from NASA and NOAA relied on uninterrupted total solar irradiance records to determine that, between 2005 and 2019, the amount of solar radiation remaining in the atmosphere Earth nearly doubled.
“To make sure we can continue to collect these measurements, we need to make devices as efficient and cost-effective as possible,” says Harber.
CTIM is a prototype: its flight demonstration will help scientists determine if small satellites can measure total solar irradiance as efficiently as larger instruments, such as the total radiation monitoring (TIM) used on the finished device SORCE mission and what’s going on TSIS-1 mission on the International Space Station. If successful, the prototype will enhance the approaches used for future tools.
CTIM’s radiation detector utilizes a new carbon nanotube material that is capable of absorbing 99.995% of incident light. This makes it well suited for measuring total solar irradiance.
Credit: Tim Hellickson / University of Colorado, Boulder
Reducing the size of a satellite reduces the cost and complexity of deploying that satellite into low Earth orbit. That allows scientists to prepare backup devices that can keep a record of TSI data should an existing device fail.
CTIM’s new radiation detector – also known as a beammeter – takes advantage of a new material developed with researchers at National Institute of Standards and Technology.
“It looks a bit like a very, very dark fluffy rug. It was the blackest substance ever made by man when it was first created, and it continues to be a particularly useful material for observing TSI,” Harber said.
Made of microscopic carbon nanotubes arranged vertically on a silicon wafer, the material absorbs nearly all light along the electromagnetic spectrum.
Taken together, the CTIM’s two electronic meters take up less space than a quarter’s area. This allowed Harber and his team to develop a small instrument suitable for collecting total radiation data from a small CubeSat platform.
A sister instrument, the Compact Spectrophotometer Radiator (CSIM), used the same bolt in 2019 to successfully explore the variation in the light bands present in sunlight. Future NASA missions could merge CTIM and CSIM into a single compact instrument for measuring and analyzing solar radiation.
“Now we’re asking ourselves, ‘How do we take what we’ve developed with CSIM and CTIM and integrate them together,’ Harber said.
Harber expects CTIM to begin collecting data about a month after launch, currently scheduled for June 30, 2022, aboard STP-28A, a Space Force mission led by Virgin Orbit perform. When Harber and his LASP colleagues open up CTIM’s solar panels and examine each of its subsystems, they activate CTIM. It is a delicate process, one that requires diligence and care.
“We want to take our time and make sure we are taking these steps rigorously and that each component of this device is working correctly before we move on to the next step,” says Harber. . “Just proving that we can collect these measurements with CubeSat would be a big deal. That would be very satisfying. “
Sponsored through Invest program in NASA’s Office of Earth Science Technology, CTIM launches from Mojave Air and Space Port in California aboard Virgin Orbit’s LauncherOne rocket as part of the US Space Force’s STP-S28A mission.
Another graduate of NASA’s InVEST technology program, NACHOS-2, will also participate. One NACHOS CAKE twin, NACHOS-2 will help the Department of Energy monitor trace gas in the Earth’s atmosphere.
By Gage Taylor
NASA’s Office of Earth Science Technology
Banner Image: NASA’s Compact Total Radiation Monitoring Instrument (CTIM), will help researchers better understand how solar energy impacts countless Earth systems. Image supplier: Tim Helickson / University of Colorado, Boulder
Last Updated: July 5, 2022
Editor: Ellen Grey
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