Tanager-1 can map large methane plumes from orbit. A plume is a patch of extra methane moving through the air. What happens after a source appears on the map is the harder question.
An Undertold interactive · 26 July 2026 · Diagrammatic art rendered in code
MEASUREDReflected light reaches the sensor.
COMPARED / DERIVEDSoftware compares usable readings and derives methane-like evidence.
INTERPRETED CAUTIOUSLYShape, context, and modeled wind may support an approximate candidate.
HANDED OFFPeople may review, investigate, or act; the evidence cannot compel them.
DIAGRAM — NOT SATELLITE IMAGERY
Diagrammatic illustration · not satellite imagery
Chapter one
Two passes over a pipeline
On October 9, 2024, Carbon Mapper says Tanager-1 observed a large methane plume from a Permian gathering pipeline. Agencies relayed the finding to the operator. The operator reported a voluntary repair. In an October 24 observation, Carbon Mapper detected no methane plume.
Those are four different claims: an observation, a notification, an operator-reported repair, and a later observation. Carbon Mapper and a partner report the whole sequence; the two satellite observations do not by themselves prove what happened between them.
09 OCTPlume observed
NEXTAgencies passed on the finding
OPERATOR REPORTVoluntary repair
24 OCTNo plume found on this pass
OPENWhat can this prove?
The sequence traces how an observation from orbit may become actionable evidence on the ground. Its provenance matters, however: the account comes from Carbon Mapper and a partner, not from an independent review of each source in the chain.
In this reported case, the handoff mattered because the operator chose to act voluntarily. Detection could inform that decision, but it could not compel a repair.
What the second pass can say: the later pass found no plume above the applicable limit under those conditions. That non-detection is consistent with a stopped or reduced plume. By itself, it does not establish the repair mechanism or prove that emissions stopped permanently.
Chapter two
Why look for the few
Methane and carbon dioxide both trap heat, but they do not act on the same timetable. Pound for pound, the IPCC’s Sixth Assessment Report puts methane’s warming potential at 81–83 times that of carbon dioxide over 20 years and 27–30 times over 100 years. Methane remains in the atmosphere for about a decade on average, far less time than carbon dioxide.
That is why the story treats methane as a near-term target. The comparison is strongest over 20 years and smaller over 100 years, so the time horizon belongs with the number. “Eighty times worse” without one is not an honest comparison.
81–83×20-year warming potential
27–30×100-year warming potential
~10 yearsaverage atmospheric lifetime
In one peer-reviewed survey from the air, researchers examined more than 272,000 pieces of California infrastructure. A point source is one concentrated source. Among the point sources the survey detected, 10% produced about 60% of the measured point-source methane emissions. The detected sources represented roughly 0.2% of all the infrastructure surveyed.
That unusually high-emitting tail is the “few” in this chapter. It is often described with the term super-emitter, but the term has no single cutoff across every industry.
These numbers apply only to this survey—its place, period, and detection ability—not to the world. Carbon Mapper uses 100 kg CH₄/hour as a reference; the U.S. oil-and-gas Super Emitter Program uses the same cutoff for that program, not as a universal definition.
Interaction one · ambient
Light carries a fingerprint
Sunlight reflects from the ground and travels through the atmosphere to the sensor. Methane absorbs particular wavelengths along that path, leaving dips—or notches—in the measured light pattern. Move left or right—or use the arrow keys—to try five viewing positions. The narrow strip is the swath: the part of the ground being measured. Open the methane-sensitive pattern to inspect the notches.
The five positions change only the viewing geometry in this schematic; the methane-sensitive pattern and its notches stay the same.
Instrument plate 01Position 3 of 5, centered. Methane-sensitive pattern closed.
Position 3 of 5 · centered12345
SUNLIGHT INREFLECTED LIGHT TO SENSORMEASUREMENT SWATHDERIVED ENHANCEMENTNOT VISIBLE COLORSCHEMATIC LANDSCAPE
Methane-sensitive pattern
Measure returned light.
Compare where less light returns.
Infer a methane-like pattern.
Ordinary reflected-light referenceMeasured returned lightMethane-sensitive notchesWavelength runs left to right
Band
Schematic signal
Ordinary reflected light
Broad reflection from the surface
Methane-sensitive pattern
A pattern of missing light linked to methane
Illustrative, not to scale. Methane is inferred from patterns in reflected sunlight; it is not photographed as a visible cloud. This is not a live satellite view.
Advertisement
Ad slot · network embed intentionally absent
Chapter three
Reading the missing light
Tanager measures sunlight reflected from Earth’s surface across many visible and shortwave-infrared wavelengths. Taken together, those measurements form a spectrum. Methane and carbon dioxide each leave a distinct pattern of missing light within it.
MEASUREDReflected light reaches the sensor.
COMPARED / DERIVEDSoftware compares usable readings and derives methane-like evidence.
INTERPRETED CAUTIOUSLYShape, context, and modeled wind may support an approximate candidate.
HANDED OFFPeople may review, investigate, or act; the evidence cannot compel them.
From reflected light to an approximate candidate
Measure the reflected spectrum.
Compare usable readings with nearby background.
Derive an enhancement for each pixel.
Check shape and context.
Estimate this pass using modeled wind.
A pixel is one small area in the image. For each usable pixel, Carbon Mapper’s system estimates the extra methane above the surrounding background—the nearby level used for comparison. That extra amount is called an enhancement. The system then checks whether the enhancement’s shape and setting support a credible source at the surface.
From the estimated extra gas, the plume’s length, and a modeled wind speed, the system estimates an emission rate for that observation. The result is model-based and sensitive to wind: it is not a meter attached to the equipment, and it is not, by itself, a yearly average.
OrganizationCarbon Mapper says it was founded in 2020 with philanthropic support, after more than a decade of earlier research. Its coalition includes NASA’s Jet Propulsion Laboratory (JPL), Planet Labs, the California Air Resources Board, the University of Arizona, Arizona State University, and RMI.
InstrumentTanager-1 launched on August 16, 2024. Planet built and operates the spacecraft. NASA’s Jet Propulsion Laboratory designed the instrument that measures the light spectrum.
SpecificationCarbon Mapper’s published final-orbit specifications list 30-metre image pixels in its derived methane layer and a measured strip 18.6–24.2 kilometres wide. Before launch, the instrument was specified to have a 90% chance of detecting methane releases of 90–180 kg CH₄/hour under stated reference conditions.
A 30-metre pixel cannot identify an exact valve. The 90–180 kg CH₄/hour specification assumes wind of 3 m/s, a 35° solar-zenith angle, 25% surface reflectivity, and 30-metre pixels. It describes a probability under those conditions—not a universal cutoff proved by independent tests.
Interaction two · observation
One pass, pixel by pixel
Move through five stages of the same made-up satellite pass. Each square stands for one image pixel in this lesson. First ask whether the square has a usable reading. Then compare its light pattern with a clear background, mark any estimated methane enhancement, and outline an approximate source area. Cloud, a dark surface, or noise can make a square unavailable; unavailable means no usable reading, not zero emissions.
The selected square remains the comparison. The magenta squares are computer-derived possible increases. The dashed outline marks an approximate source area, not exact equipment.
Surface: ordinary made-up surface; no methane conclusion yet.
Map reading guideStage 1 of 5
Columns123456789101112
Rows12345678
Selected(2,2)—clear comparison area
Approximate possible source area Interpretive boundary — not exact equipment
APPROXIMATE POSSIBLE SOURCE AREA boundary is interpretive / not exact equipment
Open keyboard grid — 96 squares
Text and keyboard alternative: 8-row made-up classification grid
Row
Columns 1–12 · coordinate and classification
Made-up observation for explanation. This is not Carbon Mapper portal data, a current event, or a map drawn to geographic scale. A colored square marks an estimated methane increase; it is not a photograph of methane. Real Tanager methane images use 30-metre pixels, but this grid does not claim any geographic size. A masked square means no usable reading—not zero emissions.
Chapter four
A map of moments
Carbon Mapper’s public portal assembles observations from several instruments. The collection spans Tanager-1; NASA’s EMIT instrument on the International Space Station; aircraft campaigns using instruments such as NASA AVIRIS; and Arizona State University’s Global Airborne Observatory. After registering, people can use the website or connect through its data interfaces, called the Data and STAC APIs.
Carbon Mapper reported these results from Tanager-1’s first methane detection on September 19, 2024, through September 16, 2025: 5,392 published methane plumes, 1,234 published carbon-dioxide plumes, and 3,563 Tanager-derived sources that contained published plumes.
5,392methane plumes reported
1,234CO₂ plumes reported
3,563Tanager-derived sources with published plumes
These are Carbon Mapper’s reported operating totals for those dates. They are not independently verified measures of climate impact. A plume, a source, an event, and a super-emitter are different things. Public access also does not mean anyone may use or redistribute the data for any purpose. Carbon Mapper describes the data as available for non-commercial use and applies terms to other uses.
Chapter five
The handoff
A candidate observation is evidence worth following up, not a verdict. From there begins an institutional chain: someone reviews what the evidence may show, passes the finding to a person or agency able to investigate, and decides whether action is warranted. None of those steps is automatic; authority and willingness still matter.
MEASUREDReflected light reaches the sensor.
COMPARED / DERIVEDSoftware compares usable readings and derives methane-like evidence.
INTERPRETED CAUTIOUSLYShape, context, and modeled wind may support an approximate candidate.
HANDED OFFPeople may review, investigate, or act; the evidence cannot compel them.
Review what the evidence may show.
Interpret its limits.
Pass the finding onward.
handoff gap
Investigate.
Decide whether action is warranted.
Authority and willingness matter; no Carbon Mapper-wide alert-to-repair rate is established.
The public sources reviewed for this story do not show how often a Carbon Mapper alert leads to a repair. For wider context, UN News reported in July 2026 that only 13% of alerts from UNEP’s Methane Alert and Response System received a response from a notified government or operator. That is not Carbon Mapper’s response rate. It shows only that sending useful information does not guarantee action.
A plume alone cannot show who is responsible, what caused it, whether anyone was negligent, or whether the release was illegal. It is a finding worth checking further.
Interaction three · centerpiece
From observation to a cautious finding
Work through a simplified review of a made-up observation. First decide where the measured light provides usable evidence. Then compare the methane-sensitive pattern, check the shape and context, test a modeled wind assumption, and choose whether the evidence supports a candidate observation. Candidate means ready for follow-up—not a confirmed owner, cause, violation, or repair.
1 · Reading
2 · Light
3 · Shape
4 · Wind
5 · Decision
6 · Later pass.
NEEDEDusable reading
NEEDEDclear background comparison
NEEDEDmethane-like difference
NEEDEDconnected shape/context
NEEDEDmodeled wind noted
NEEDEDcandidate observation
First, check where a reading is usable
Show the marked areas where cloud, a dark surface, or noise blocks a usable reading. Then choose one clear area for comparison.
Areas with no usable reading checked.
Clear comparison area chosen.
Compare the possible plume with a clear area
First choose a clear comparison area. Then look for the methane-like pattern of missing light in the possible plume.
Check whether the possible plume forms one connected shape
These are three separate made-up examples on the same grid. Only one example is shown at a time.
See how the wind assumption changes the estimate
Wind is an input to the estimate, not a separate result in this lesson. Change the made-up wind assumption and the relative estimate changes with it. The chart has no emission-rate units and does not calculate a real source’s emissions.
The synthetic observed plume evidence stays fixed. A stronger assumed wind raises the modeled release-rate estimate needed to produce that same evidence.
You can record only an observation supported by the checks above. Otherwise, wait for more evidence.
Compare this finding with a later pass.
Later synthetic observation
A later pass asks a new, limited question: under its own conditions and detection limits, was a plume found, not found, or was no usable comparison possible? It does not answer by itself whether a repair happened or emissions stopped for good.
A candidate plume appears again. Repetition can strengthen evidence of recurrence, but does not resolve ownership, cause, or legality.No plume is detected above applicable limits under these later synthetic conditions. This does not prove repair or permanence.No usable later observation. Conditions prevent comparison.
Earlier pass
Later pass
What this comparison supports
Cautious finding
Quality masks and usable background checked.
Candidate and background spectra compared.
Shape and context interpreted.
Modeled wind dependency reviewed.
Later state qualified.
Ready to hand off is not a verdict. The checks can support recording a candidate observation. They do not settle owner, cause, legality, repair, or permanence.
This made-up lesson is not Carbon Mapper software and is not connected to its systems. You are reviewing a made-up observation, not controlling or directing a satellite.
A possible source area does not identify the exact equipment, owner, cause, legality, or responsibility. If a later pass finds no plume, that alone does not prove a repair or show that emissions stopped for good.
Advertisement
Ad slot · network embed intentionally absent
Chapter six · honest ledger
What one pass cannot tell you
The instrument’s limits are not side notes. They shape the meaning of every apparent blank.
Timing
Carbon Mapper says Tanager observations usually appear in the public portal within 30 days. The portal is not real time. Some collaborators may receive early “quick-look” results within a few days, but those results can change after review.
Coverage
Tanager-1 is a targeted imager, not a satellite that watches every place continuously. Its swath has a finite width, and its imaging capacity is limited, so the team must choose where to point it. How soon it can return depends on orbit geometry, priorities, competing targets, cloud, and the number of satellites available.
Conditions
The method depends on reflected sunlight. Cloud, haze, smoke, dark surfaces, the Sun’s angle, and a complex background can degrade or block a reading. Wind uncertainty carries directly into the estimated rate. A release may also be intermittent, starting and stopping between passes.
Meaning
Attribution—the best-effort judgment that connects a plume to a facility or industry—becomes harder where infrastructure is dense or ownership records are incomplete. Even then, a plume alone cannot establish whether the cause was a leak, planned venting, a malfunction, a legal violation, or a particular owner.
Not detected is not the same as not emitting.
A non-detection means only that the pass found no plume above the applicable limit under those conditions. To make a stronger claim about the cause or the law, investigators need other evidence. That may include operator records, an inspection at the site, more observations, or regulatory findings.
Independent controlled-release studies and blind tests provide useful context for satellite methane detection in general. The studies cited here did not test Tanager, however, so none supplies a performance score for this satellite.
Chapter seven
More eyes, same question
In a peer-reviewed paper led by Carbon Mapper, researchers modeled the reach of a larger satellite constellation. Under the paper’s assumptions, four satellites could detect about 60% of a reference set of high-emitting point sources around or above 100 kg CH₄/hour worldwide. The model predicted that the program would likely need ten or more satellites to reach its 90% goal.
In April 2026, Carbon Mapper announced plans for at least three more broad-spectrum Tanager satellites and one specialized shortwave-infrared Tanager. It said the specialized satellite could launch as early as 2028.
The 60% figure comes from a model. It is not coverage already achieved or independently validated. The extra satellites and launch date are plans, not current capacity or firm commitments.
More coverage could make more large point sources visible. Visibility still cannot compel a repair.
Support the work directly
Help make large emissions harder to overlook
Carbon Mapper is a Pasadena-based 501(c)(3) that works to make methane and carbon-dioxide data accessible and actionable. A donation supports the organization; it does not guarantee any particular detection, notification, or repair.
Undertold is not affiliated with or compensated by Carbon Mapper. Undertold is supported by advertising. Donations through this link go directly to Carbon Mapper; 100% goes to the charity, and Undertold receives nothing.