Artist’s rendering of MethaneSAT, the satellite EDF developed. Photo: Supplied / Environmental Defense Fund
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Somewhere in Earth's orbit, a mini-fridge-sized satellite weighing 350 kg is lost, unable to be contacted.
Named MethaneSAT, the satellite was built to precisely detect emissions of methane, a greenhouse gas that is around 80 times more potent than carbon dioxide over a 20-year period.
Despite being in space for only one year of its planned three-to-five-year lifespan, MethaneSAT did yield useful data, according to Dr Sara Mikaloff-Fletcher, the science leader for New Zealand's MethaneSAT Science Programme.
MethaneSAT launch viewing party at RocketLab in Auckland. Photo: Stuart Mackay / Earth Sciences New Zealand
New Zealand's first major government-backed space mission
While development of MethaneSAT was led by US-based non-profit the Environmental Defense Fund, New Zealand is also a major stakeholder.
The government contributed $32 million to the project, and the University of Auckland was poised to take over mission control for operation of the satellite before it went dark.
Its primary targets were large methane leaks from oil and gas fields, since plugging these is considered an easy climate win.
Direct measurement of methane in the air from an aeroplane flying over Canterbury is used to validate MethaneSAT data during its overhead passes. Photo: Stuart Mackay / Earth Sciences New Zealand
A secondary research project, led by New Zealand scientists, aimed to identify smaller, more diffuse methane emissions from agriculture - that is, cow and sheep burps.
This ability to map and quantify livestock methane was initially considered a major drawcard for New Zealand - a nation where almost half of the climate footprint comes from agricultural methane sources.
However, experts pointed out that farming methane would likely be at the very limit of the satellite's detection capabilities. Picking up a huge plume of methane leaking from oil production is much easier than spotting the diffuse methane emitted by cattle spread out over fields. Plus, any data would not add much to the country's understanding of its methane emissions profile, they said.
Still, New Zealand is the "perfect little test bed" for investigating the limits of the satellite, and developing the science of remote-sensing methane, says Sara.
That's due to both our unique emissions profile, and the country's capabilities in atmospheric measurements and modelling.
Researchers deploy a range of ground and aerial equipment across Canterbury to validate MethaneSAT data during its overhead passes. Photo: Stuart Mackay / Earth Sciences New Zealand
Ground-truthing satellite data
Before contact was lost on 20 June 2025, MethaneSAT examined 97 agricultural targets around the world, including 13 in New Zealand.
A team from Earth Sciences New Zealand used data from ground-based and airplane instruments to sense-check what the satellite was seeing from space as it passed over two agriculturally productive regions: Waikato and Canterbury.
The result is "quite a lot of data" that is "really beautiful," says Sara. "The precision looks amazing, and there's really strong alignment with what we saw from the ground-based field campaign, what we expect from the modelling we did pre-launch, and what we saw from the satellite data," she says.
PhD candidate Harrison O'Sullivan-Moffat monitors the in-situ analyser used to measure and validate MethaneSAT data during its passes. Photo: Stuart Mackay / Earth Sciences New Zealand
Analysis is ongoing to figure out the satellite's limits when it comes to agricultural methane. It can pinpoint individual facilities where lots of livestock is densely packed into a small space, like intensive feedlots in the United States, Sara says.
But whether it can detect emissions from more dispersed livestock - like our pastoral systems in New Zealand - remains an unanswered question. "It's more complicated than you think, and we're also still working on it," says Sara. "Ask me again in six months."
Loss of satellite won't stop research
MethaneSAT's persistent technical problems and eventual loss have triggered calls for a review to investigate whether New Zealand should have taken a closer look before investing $32 million into the project.
Dave Pollard installs a EM27 Solar Absorption Spectrometer in Canterbury to help validate MethaneSAT data during its overhead passes. Photo: Stuart Mackay / Earth Sciences New Zealand
Nonetheless, Sara is optimistic about the future of space-based methane detection. "Even though I'm very sad about losing the satellite, that opportunity is still incredibly exciting," she says.
The team are now pivoting to a European instrument called TROPOMI, and focusing on adapting their methods to its slightly lower precision compared to MethaneSAT.
As for MethaneSAT itself, lost in space, the future isn't so bright. "Eventually, it will decay and burn up in the atmosphere," says Sara.
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