On the morning of Jan. 8, 2025, a crimson dot popped up on NASA’s Fireplace Info for Useful resource Administration System. It was the primary signal of what would change into one among California’s worst wildfires in historical past, occurring to say a dozen lives and burn down hundreds of houses within the Palisades. All of the whereas, the Aqua satellite tv for pc was orbiting above, scanning the planet and beaming information right down to floor stations in Alaska and Svalbard.
This satellite tv for pc carries infrared sensors that seize modifications on Earth not possible to see with the human eye, making it important for coordinating emergency responders throughout pure disasters. Upon detection, NASA converts Aqua’s infrared wave information into GPS coordinates, permitting officers to plot the unfold of fireside as factors on a map. These coordinates make up what’s often known as the Reasonable Decision Imaging Spectroradiometer (MODIS), an instrument that spots fires on the Earth’s floor. This course of usually alerts emergency providers faster than 911 calls from the bottom.
Lacking information is an issue for scientists attempting to elucidate the Earth’s local weather to politicians and enterprise leaders who make selections on what to do about local weather change. Whereas the info loss is presently small, scientists say the issue will solely worsen over time as area particles will increase.
However Aqua is not alone. It is one among three predominant satellites that make up the core of the Earth Observing System (EOS), a constellation that coordinates orbit to measure the land, ocean and environment concurrently.
The EOS fleet has allowed us to grasp how aerosols have an effect on cloud formation, map the deforestation of the Amazon, and uncover how the Earth’s oceans have darkened because of phytoplankton blooms. And certainly, all three satellites — Aqua, Terra and Aura — are in danger from area junk. Beginning in 2005, the EOS fleet swerved to keep away from area particles on at the least 32 occasions. The maneuvers could have left corrupted local weather information in a number of of these cases, based on information logged by the Land Data Products Evaluations Assessment. Even past information, there may be additionally the lack of valuable gasoline.
“Even with out collisions, area particles has an financial value,” Andrew Bonwick, vice chairman at Relm Insurance coverage, which gives satellite tv for pc insurance coverage and has to cost within the danger of collision, informed House.com. “Every time a satellite tv for pc has to maneuver to keep away from a possible collision, it makes use of gasoline which is a finite and valuable useful resource.”
“Issues will worsen earlier than they get higher,” mentioned the NASA scientists within the 2018 report that assessed particles maneuvers. The report discovered that the chance of a collision between an EOS satellite tv for pc and a bit of orbital particles is growing.
In its heyday, Aqua flew round 438 miles (705 kilometers) above the floor of the Earth, transferring from the North Pole to the South Pole in an ellipse 14 occasions a day, scanning the complete planet. The satellite tv for pc sits in sun-synchronous orbit, capturing the sunshine waves emitted from the Earth’s floor.
Alongside that journey, Aqua has survived a battery short-circuiting, a photo voltaic panel thermistor failure, and misplaced 23 of its photo voltaic cell strings. However because of cautious gasoline administration, the satellite tv for pc has lasted 18 years longer than initially designed.
“If we knew we had been going to have a spacecraft and devices that might final 20 years, we’d have put extra gasoline in it in order that it could final even longer,” mentioned Aqua Mission scientist Claire Parkinson in 2022.
Local weather satellites like Aqua are extra in danger from particles as a result of they need to fly near the planet to seize their information. Low Earth Orbit (LEO) has the very best quantity of area junk, trapped there by the Earth’s gravity and travelling at quicker speeds than the higher environment.
In 2005, the European House Company (ESA) was monitoring about 16,000 items of particles. By 2026, that quantity had elevated to greater than 44,000, a rise of about 180%.
The overwhelming majority of area particles is simply too small to be tracked, with ESA estimating that greater than 1,000,000 small items are unaccounted for. Even a speck of paint could be sufficient to wreck a satellite tv for pc.
House junk is created when satellites break up in orbit, both due to collisions or anti-satellite exams equivalent to these carried out by China and Russia. On April 28, two Russian spacecraft handed inside 10 ft (3 meters) of one another.
However area junk avoidance is not the primary purpose satellites use gasoline. If left alone, Aqua would finally drift astray. Gravity from passing mountains and ocean bulges slowly pulls the satellite tv for pc out of orbit, whereas photo voltaic radiation modifications its spin, corrupting its information.
For that purpose, scientists continuously need to appropriate satellite tv for pc trajectories to keep away from spacecraft crashing into different spacecraft and even simply random bits of area junk. Whereas it is true that spending gasoline shortens the lifetime of a satellite tv for pc, avoiding area particles is often value it. Most of Aqua’s gasoline was used on orbital-course corrections.
“For functions the place satellites are tasked to offer detailed imagery of explicit areas, the job could not get achieved, particularly the place the imagery is time vital or will depend on frequent revisits,” says Bonwick.
Now, Aqua is reaching the top of its life span. It is set to be switched off this 12 months after traversing the skies for nearly a quarter-century, abandoning a legacy for future local weather scientists. Lower than 66 kilos (30 kilograms) of gasoline stays, held in reserve for the time Aqua is lowered into the environment and safely burned up. Till then, the satellite tv for pc continues its orbit, like a automotive in impartial rolling down a hill.
After it is switched off within the fall, Aqua will now not have sufficient gasoline to dodge incoming area junk. The risk of collision for U.S. authorities satellites is meant to be 1 in 1,000, however the danger will increase as soon as gasoline runs out.
In 2007, when China destroyed one among its personal satellites, a number of satellites needed to maneuver to keep away from area particles, elevating issues about the opportunity of Kessler Syndrome, the place satellite tv for pc collisions start to cascade, like dominoes.
There have been 4 confirmed area collisions, based on the ESA, however just one involving a local weather satellite tv for pc: An incident in 2021 when a bit of particles from a Russian Zenit-2 rocket hit China’s Yunhai-1 02 meteorological satellite tv for pc.
The hazard is growing, with ESA estimating a 20% rise in collision danger since 2024. Due to the elevated danger, satellites have change into virtually uninsurable, that means NGOs and authorities companies are more and more bearing the price of threats to local weather satellites.
MethaneSAT, a satellite tv for pc designed to seize methane emissions to assist higher perceive the greenhouse fuel, stopped transmitting information in 2025 solely fifteen months into its life cycle. After excessive photo voltaic exercise, the satellite tv for pc instantly shut down. Investigators could not agree why.
“If that satellite tv for pc had not been insured, that might have killed the entire firm,” says Bonwick. “It isn’t simply stability sheet safety, it is survival.”
The MODIS fire-tracking dataset is ready to proceed till Aqua and its accomplice satellite tv for pc Terra are turned off. NASA, which responded to an preliminary e mail from House.com however has but to reply particular questions regarding the problem, is constant its fireplace detection capabilities via the Seen Infrared Imaging Radiometer Suite (VIIRS), a database that survives on a number of NASA satellites.
However with the area company affected by authorities cuts, personal companies are actually filling the hole. Google has published plans to launch a constellation of satellites particularly for fireplace detection, which guarantees to seize even smaller fires at higher decision than earlier than.
On Could 4, Aqua celebrated its twenty fourth birthday. It’s going to in all probability be its final. It accomplished greater than 126,000 orbits of the Earth, and enabled at the least 30,000 scientific publications.
The satellite tv for pc leaves behind one of many longest single-satellite local weather information data ever compiled. Its contributions to local weather science shall be onerous to interchange.
