- Since 2018, the GEDI mission has been firing lasers from the International Space Station to measure aboveground biomass on Earth.
- The information gleaned from it has been crucial for scientists to understand how deforestation contributes to worsening climate change.
- The mission was supposed to be decommissioned earlier this year, with the lasers fated to be jettisoned from the ISS and burned up in the atmosphere.
- However, NASA made a last-minute decision to extend the mission after a push from the scientists involved in it: the GEDI equipment will be put into storage for 18 months, then reinstated to resume operations for as long as the ISS continues to run.
It was down to the wire for the GEDI mission, but it now seems like the force may have prevailed.
In a last-minute decision, NASA has decided to extend the GEDI mission (short for Global Ecosystem Dynamics Investigation, and pronounced “Jedi” like in the Star Wars films), which was fated to be jettisoned from the International Space Station, where it has been attached for the past four years, to make way for another, unrelated, mission. But a campaign driven by the scientists involved in the project helped the mission — the first to map Earth’s forests in 3D — get a second life.
NASA now says the mission will take a hiatus for 18 months. The array of lasers that make up the GEDI equipment will be moved into storage on board the ISS, where space for research equipment is at a premium, to make way for a U.S. Department of Defense payload.
“The proposed solution calls for temporarily moving GEDI to an alternate location, where it will remain offline for about 18 months while a DOD technology payload completes its mission,” NASA said in a statement issued March 17. “In 2024, GEDI will return to its original location and resume operations on the station.” The mission is now expected to “continue through the life of the space station,” which is set to be retired in 2031.
Data from the GEDI mission, operating since 2018, has been critical for scientists to understand how deforestation is exacerbating climate change.
“This mission is particularly valuable, especially at the point where we are in now, in terms of climate negotiations and the recognition of mitigation efforts,” Scott Goetz, deputy principal investigator at the GEDI mission and a professor at Northern Arizona University, told Mongabay in a video interview. “It means a lot to me and my group, but it means a lot more for the broader scientific community as well.”
The GEDI mission uses spaceborne laser altimeters to measure the aboveground biomass on Earth. Scientists calculate the dimensions of trees based on the time it takes for the light emitted from the ISS to hit the tree and reflect back. Since the light also reflects off leaves and branches, the GEDI mission has also helped scientists get a fuller understanding of what a tree looks like, including details about girth, weight and canopy size.
Modeling forests in 3D is imperative to estimate the amount of carbon stored in them. About half of a tree’s dry weight comprises carbon, which is released into the atmosphere when it’s cut down or is burned up in a fire. When scientists and researchers can calculate the amount of carbon stored in an area of forest, it gives them a clear picture of how the carbon is distributed and how much is released due to deforestation.
Since GEDI data became publicly available in 2020, researchers and governments have been using it for a variety of applications.
Thomas Crowther, a professor of ecology at ETH Zurich, has used data from the mission to study biodiversity around the world. It’s helped aid his understanding of how changes in the structure of the ecosystem affect biodiversity in different regions, he said.
“For example, the diversity of birds can change as the forest structure changes,” Crowther told Mongabay in an email interview. “Therefore, when we are trying to model the variations in bird diversity, it is incredibly useful to have GEDI data that shows how the structure of the ecosystem changes across forest landscapes. We use this, and similar approaches to understand all aspects of biodiversity.”
Researchers have also used data from the mission to map the Amazon Rainforest in 3D. Using the data, scientists were able to confirm some well-documented facts, such as the high levels of deforestation in the Brazilian Amazon. They were also able to identify pockets of the rainforest with higher levels of aboveground biomass, like in the northeastern region that covers northeast Brazil, French Guiana and Suriname, and the southwestern region, which lies largely in Peru.
This mapping of the Amazon “highlights some key areas for specific carbon-based conservation which represents a whole new line of conservation, in addition to previous biodiversity or ecosystem-based conservation,” Matt Finer, a senior research specialist at the nonprofit Amazon Conservation Association, told Mongabay in a video interview in September 2022.
Data from the GEDI mission has also helped countries like the U.S. and Paraguay improve the accuracy of their respective national forest inventories.
The GEDI equipment is currently in storage in the Japanese Experiment Module of the ISS. But its maintenance there is not an easy feat.
“The temperature changes in the space station orbit are quite dramatic,” Goetz said. “We are hoping it has sufficient cooling to deal with these changes because it goes from a cold, dark environment at night into the sunlight.”
Nevertheless, Goetz said he’s hopeful that the heating and cooling systems they’ve installed will help the equipment last through the 18 months of storage.
“For now, we are just really excited that we will get more data in 18 months,” he said. “It will be current and relevant to much of the climate change negotiations and solutions that the world is trying to implement at this point.”
Banner image: The two-stage Falcon 9 launch vehicle lifts off Space Launch Complex 40 carrying the SpaceX’s Dragon resupply spacecraft to the ISS. Dragon will deliver several science investigations to the space station, including the GEDI. Image by NASA.
Abhishyant Kidangoor is a staff writer at Mongabay. Find him on Twitter @AbhishyantPK.
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