Rocket Lab’s “Ready, Aim, PREFIRE” mission successfully lifted off on May 25, 2024, at 07:41 UTC from Launch Complex 1 (LC-1), Pad B, on New Zealand’s Mahia Peninsula. The payload is currently in a near-polar sun-synchronous orbit, passing 525 km above the two poles. Meanwhile, NASA’s second satellite PREFIRE-2 is scheduled to launch in less than three weeks.
NASA’s Polar Radiant Energy in the Far-Infrared Experiment (PREFIRE) is designed to measure the far-infrared radiation emitted from the poles. Current knowledge indicates that about 60% of this heat in the polar region escapes to space via infrared wavelengths.
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The role of PREFIRE in monitoring climate change
Equipped with a Thermal IR Spectrometer (TIRS), the satellite can split and measure infrared light in a vast area of the poles, particularly the wavelengths longer than 15 μm (FIR) that have never been systematically measured. The mission aims to bridge data gaps and improve existing climate models to better predict the role of climate change.
The Arctic is warming faster than any other region on Earth. Understanding infrared emissions from the poles is crucial to comprehend why ice loss is accelerating more rapidly than in other parts of the world. Most of the solar radiation is absorbed and transported toward the poles by the atmosphere and oceans. The ice of the poles then, radiate much of its heat upward in the form of infrared radiation.
The cause of such phenomena is associated with the triatomic structure of molecules like water, ozone, and carbon dioxide. These molecules can absorb frequencies corresponding to infrared radiation due to the asymmetric stretching and bending of their vibrational modes. This absorption temporarily changes their dipole moment and spontaneously releases it returning to their lower energy states.
The fast ice melting is then trivial to be associated with carbon dioxide. Since 1990, global CO₂ emissions have increased by more than 60 percent. This drastic increase is influencing the amount of radiation emitted by the poles, which poses the basis for adequate models to improve the predictions.
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PREFIRE and a look of previous space-to-Earth polar missions
Tracing the history of polar missions investigating climate change involves looking back to a series of key factors. To monitor the poles, the behavior of atmospheric temperatures, pollution, and extreme events can’t be neglected.
One of the first launches into the study of Earth weather was NASA’s successful TIROS Program (1960s) to determine if satellites could be useful in studying climate change and atmospheric evolution.
Many other satellites have progressively revealed new aspects of Earth. The Nimbus Satellites (1964-1978) focused on studying sea ice and surface temperature, and the Landsat Program (1972-present). Both introduced new aspects of monitoring glaciers, ice sheets, vegetation, and cloud cover since now.
Modern satellite missions have introduced increasing advancements, such as NASA’s Terra and Aqua models (2000-present), GRACE and GRACE-FO (2002-present), ESA’s CryoSat (2010-present), and the Sentinel satellites (2014-present). These missions have focused on cutting-edge studies of ice cover prediction, greenhouse gas concentrations, ice mass balance, and providing detailed radar and optical imagery for ice coverage.
All these experiments have created a large amount of data since the 1960s and are crucial for developing effective strategies to mitigate and adapt to the consequences of climate change. Now PREFIRE-1 and PREFIRE-2 will finally lead to a better understanding of how the poles radiate heat into space, and thus crucial for developing effective strategies to mitigate and adapt to the consequences of climate change.
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