Methane detection from space![1] will aid in the detection of greenhouse gas emissions from abandoned well-heads, oil-fields, landfills and other large environmental polluters contributing to climate change. The IEA[3] has attributed nearly 30% of global temperature rise to methane, so the detection of the sources is becoming a critical factor in mitigating direct and indrect impacts of climate change. The sensors aboard the MethaneSAT, as well as other deployed capabilities, are largely based IR detections with tunable bandgap materials like HgCdTe[2] arrays. HgCdTe allows for the detection of non-ionizing IR via bandgap tuning of the direct semiconductor CdTe. IR bands, and thus chemical specific detections, can be selected based on the Hg doping. Similar technologies in the James Webb NIRCam enable detection of red-shifted gamma rays that are now heat photons.
I was curious on this so did some quick searching around.
Average satellite launch releases 57 tons of Co2 [1]
2.75 million unplugged wells in the US that output "6.6m tons of Co2 worth of methane" [2], or put in another way each well puts out 2.4T of Co2e each per year.
With these numbers each sat would have to prevent 23.75 years worth of a well being uncapped to recoup the cost of launch (so would have to close one well for 23.75 years, or 24 wells for a little less than a year).
> 2.75 million unplugged wells in the US that output "6.6m tons of Co2 worth of methane" [2], or put in another way each well puts out 2.4T of Co2e each per year.
Per the article you cited, the 6.6m tonnes (not tons) of CO2e does not have a lot of empirical measurements behind it, and it may be much higher. That's one of the things these satellites can help to improve.
I think a better way to look at it is comparing the 57t of emissions with other sources of CO2 emissions. For example, a single cross-country flight puts out in the range of 300-350t of CO2 (~1t per passenger). So launching 6 of these satellites in separate launches would be equivalent to a single airliner flight, i.e. negligible in the grand scheme of things.
Your link says around 57 tons for a "typical" payload launched by the ESA using an Ariane 6 rocket and <15 tons for a payload that launches from a reusable platform. The parent article says these are launching using SpaceX rockets, which are reusable, so presumably their footprint is lower than an ESA satellite. They're also extremely small satellites and not exactly typical payloads. Possibly they can even fit multiple satellites on a single launch.
Clearly the utility of these instruments is not a single item.
One would imagine that monitoring of this sort is critical infrastructure for monitoring remote & continuous emitters.
Someone has already motivated many of these science missions, and they are not funded, to my knowledge, by industry. These are already rolled into govt investments so really the argument is not total CO2 balance, but what technologies can be deployed next year that will give you continuous reductions over time.
_Many_ people will argue their clean-tech _will eventually_ provide savings, not many can be installed next year at scale.
This is an obvious choice IMO, if for no other reason than people cannot out-right emit with no consequences.
For what it's worth, Spacex's next generation rocket burns methane directly, into CO2 which is a less potent greenhouse gas. That means that if solar power is used to create methane from the CO2 in the atmosphere, then the rocket will be carbon neutral. And if waste methane is used (commonly vented to atmosphere because the market is small yet it is expensive to capture) then each launch will actually be a net benefit for reducing atmospheric greenhouse gases.
Oh hey, I wrote some of the flight software for one of those programs.
Something to note for those not familiar with satellite GIS stuff, the more satellites you have up there taking measurements, the more frequently you get data on emitters. Also, you can combine the datasets and sometimes increase the effective resolution. Additionally some are point trackers and some are mappers, they serve different purposes for localizing vs quantifying emissions.
Finally, there are some politics involved with various groups, some want access to data to name and shame, some want to do climate research, etc. It's a bit complicated on that front.
Putting aside the climate aspects and just concentrating on companies that are trying to identify methane leaks: If I have a device that can accurately see methane leaks, I am very surprised it's really more economical to put them on satellites than to operate them locally. Yes, I get that you can have one device in orbit that can do the job for multiple companies, but satellites are just fantastically expensive. Unlike photography, where the alternative is to use an also-expensive airplane, why can't companies just survey from the ground?
Are they? A CubeSat can be launched for less than $100k, and their payload can contain off-the-shelf consumer hardware. That's what some upper-middle class families pay for an extra car. I think you're overestimating the cost of satellites.
At the same time, you're underestimating the challenges of operating a ground sensor network. How would identify which sites to survey from the ground without a broader search? Would the oil industry get to regulate itself? What about temporal variability or detecting flares? How would you detect new leaks and add new sensors? What about large-scale natural leaks that spread over many kms in inaccessible terrain?
Even assuming you could pinpoint the location of every active methane source ahead of time, how would you get a sensor there? How would you secure access for installation and maintenance? How would you ensure connectivity? How would you monitor in areas controlled by hostile governments?
Each of the hundreds of thousands of sites has its own logistical challenges
which explode the cost. And because you need to keep the sensor network up to date, it's a constant operational battle, not a one time expense. Compare that to a satellite: the one-shot launch, then lower cost, lower operations, and superior temporal detection abilities and global coverage - not hard to understand why satellites are preferred.
I mostly agree but the $100k is only launch cost, it doesn't include the engineering and manufacturing of the satellite or the ongoing operational costs.
$100k would only hire a single employee, it wouldn't even cover getting them into the field let alone setting up and maintaining infrastructure over the course of a year.
It's possible to reduce this number by taking advantages of labor conditions and goodwill, but that turns out to be a ton of legwork if you want a reliable team in the area year after year.
For example, in an anthro field school you might source local labor by identifying people who want to learn about their ancestors, and you'll expect a lot of community outreach and Q&A sessions around what you're studying.
You could attempt a similar approach for studying methane but I'd personally expect the Q&A sessions to include a heavy undertone of "convince me we shouldn't just kill the people involved", and all of my arguments against would be from the perspective of a system they don't really give a shit about. I'd certainly never put myself in that position.
Companies do survey from the ground, and for large facilities there is often permanent monitoring.
Detecting methane from the ground still requires an expensive instrument, and it covers a very tiny area.
Having said that, a lot of methane leaks are from abandoned well heads, and in many places there just are no economic incentives to care about it.
Anyway, satellites are not cheap from a capex standpoint, but they are surprisingly cheap in terms of $/m^2. A camera moving over the earth at 7km/s mapping a 200km swath can cover a million square km for O($1000). Getting a team with expensive equipment into the field for a day on one site could easily be more than that.
I used to work on this at a methane monitoring shop. Others have good points.
Monitoring from the ground using methane sensors that detect the gas directly requires a lot of human labor. You need to send people out to often remote locations to set up bulky tripods full of (still expensive) sensors. You need some expensive data backhaul because these places often don’t have cellular access. We were billed by the byte to have a 24/7 contract with uptime guarantees in some of these locations. One big issue is that the companies paying for self-monitoring want suspiciously low false positives (for legal compliance reasons). You have to work with the land owners if you expect them to let you put sensors on their sites. This limits who can access that data compared to a NGO running a satellite, and requires you to filter out “noise” that’s probably not noise to appease the customers. They’re also not very accurate at detecting source in that close distance. Gases tend to quickly rise above where a human can place a sensor array and the wind and environmental factors play a huge impact. Very few companies are willing to stand behind their physics modeling with any kind of SLA. The human cost also shouldn’t be understated: when my coworkers would go and set up these sensors they’d be dizzy for days/weeks due to the emitted gasses they breathed in, our employer basically couldn’t find affordable medical insurance for us.
If you want to use spectroscopy/cameras, you can do it from a (small) distance. But it’s fantastically expensive equipment that only can be used for 1 site. And the “looking up” angle is worse than “looking down”. It’s an open question in the industry if the data can be trusted from these setups. You still have a lot of the complexity of maintaining them and exfiltrating the data.
If you want to just fly a plane… that’s expensive, you need to do it regularly, you still have a lot of “not actively monitored” time, etc.
In calibrating satellites getting folks like you to go out with sensors on the ground to send back well vetted data is an expensive and limiting factor. Much cheaper (and often preferred) to do as much as possible from space and do smart ground processing/data analysis to build confidence.
Ground-based sampling has different capabilities, e.g. these days you can mount a small mass spectrometer (see the ones going to Mars, the Moon) or related devices on a drone and get data about a much wider range of particulates and compounds. e.g.
"VOC Sampler on a Drone Assisting in Tracing the Potential Sources by a Dispersion Model - Case Study of Industrial Emissions" (2023)
> "Two plants which manufacture petrochemical products at an industrial complex in Kaohsiung City, southern Taiwan, were applied as the targets for VOCs sampling and further qualitative and quantitative analysis in the laboratory. Aromatic hydrocarbons, including toluene of 433 ppb, ethylbenzene and xylenes of 100–200 ppb and phenol of 111 ppb were identified."
I had to dig into this very topic for a previous product that I was managing.
Satellite photography/sensing vs Airplane based vs UAV based vs local vs point detection.
The higher the altitude of your sensor, the larger the swath of land you can sense, but with height comes tradeoffs... cost, weather, satellite availability, latency/how often the satellite is going to be over where you want to sense just to name a few.
Closer to or on the ground means you can get pinpoint accuracy but that comes with increasing cost of labor. Think cost of an airplane or UAV pilot vs an individual walking around with a methane sensor sniffing around flanges, valve stems, etc.
The different approaches are somewhat complimentary. Satellite can you tell you've got a problem area. You can then deploy people on the ground to "zoom in", but if you're operating a ton of sites, you wouldn't start on the ground.
It's probably simply efficiency. You can check an entire pipeline faster from space than from the air, and from the air vs. the ground. Those efficiencies save a fair bit of money, and probably also lead to earlier detection.
And while they are expensive, we're talking about low single-digit millions of dollars for a satellite which has a lifespan of 5+ years. Relatively inexpensive for the companies who would want to use them.
I can't imagine it's cheaper to do terrestrial search for methane leaks unless your goal is to only find the methane sources you are incentivized to find, and the cost of the satellite gets amortized over thousands of sources and millions to billions of stakeholders.
"putting aside the climate aspects" (???) It's 2024, this is the equivalent of putting a bit "#if 0/#endif" around your comment. I'm taking the time to post this because I hope if you reflect on it, over time, you might realize that the devil actually doesn't need an advocate.
> why can't companies just survey from the ground?
From a layman's perspective:
(1) the incentive is not aligned to accurately report leaks [1][2][3][4][5]
(2) Satellites provide global monitoring. This reaches to places/countries/regions that are not regulated, and secondly provides monitoring for natural sources of methane emissions (eg: permafrost). For the latter, even if there is nothing to be done about natural emissions, the more accurate data will provide for better modelling and help humans better understand the Earth's ecosystem.
[4] July 2023: "Australian Fossil Fuels Giants Severely Underestimate Methane Leaks" - "Fugitive — or hidden — methane emissions in the country are likely underestimated by 80% for coal and 90% for oil and gas, a new report from IEEFA say" https://www.bloomberg.com/news/articles/2023-07-04/australia...
Companies and countries tend not to report catastrophic methane leaks (or really any contamination event) unless they're caught in the act. It's absolutely staggering the rate at which methane leaks are identified now that satellite data is being analysed and published.
It'd be much more efficient all round for firms & countries to just test locally & report their methane leaks, but they can't be trusted to do so.
Ground-based sensors historically undercount methane emissions in 3rd party trials. They have a limited FOV which makes it hard to accurately measure a plume of gas, particularly when the wind blows. I suppose you could create a Dyson sphere of fixed sensors around an O&G asset, but that quickly becomes more expensive than a space based sensor.
Because these leaks can occur spontaneously, you really want real-time, continuous monitoring of a wide area with high resolution. Aerial sensors are impractical for this purpose. Only a large constellation of satellites can offer this.
The short answer is to measure methane you rely on methane absorption features. To do that you need to be looking at a source through the methane plume, from a satellite this source is the ground. From a ground instrument you can use the sun as a source, but it limits the times of day/direction/location you can measure from.
This has become less and less the case over the last decade or so. There are more or less mass-produced satellite buses now, and a SpaceX rideshare puts 150kg into orbit for less than a million. If you go small, you can probably procure, launch and operate a satellite for less than $1000 per day of usage.
>>"Despite the small army of probes in orbit, and an increasingly large fleet of methane-detecting planes and drones closer to the ground, our ability to identify where methane is leaking into the atmosphere is still far too limited. "
And a lot of nice detail is provided about particular satellite programs
> "The retrieval of methane from space measurements typically relies on spectrally-resolved measurements of solar radiation reflected by the Earth's surface in the shortwave infrared (SWIR) part of the spectrum (~1600–2500 nm). Methane presents two absorption bands in this region, a weaker one around 1700 nm and a stronger one around 2300 nm. Carbon dioxide, nitrous oxide and especially water vapor also present optical activity in the SWIR (see Fig. 1)"
I'd think it's also useful for economists and investors trying to factor activity from other countries without any middle-people obfuscating the data. That kind of information will always find funding.
I think this is overall a positive and good approach to control climate change. 1. It targets methane which has a huge short term effect on global warming vs CO2 2. It doesn't blame or target consumers with high annoyance, low value solutions like paper straws. 3. It reduces waste. We shouldn't be wasting natural gas, it's a valuable resource, and it may be economically viable to use even minor resource pockets in the future. 4. Companies shouldn't be able to freely pollute, including long term flaring, if it's so simple to cap these things. 5. This is something that's actually measurable and trackable. Analysts can identify the top 100,000 sites and governments and NGOs can go down the list to close / capture them and also show progress publically.
With permafrost thawing and arctic warming releasing methane clathrates, methane has been on my mind for a while. I wonder if these satellites will also be useful in detecting dispersed wide-area releases like these?
The current publicly available tools like https://methane.jpl.nasa.gov/ seem to focus on showing methane plumes. Which is good & something we are better positioned to do something about. But I wonder if these tools might help us see both impact of the already underway colossally fast climate change we are undergoing, which will only speed up all the faster as these trapped sources make their way out to the atmosphere.
There's also the aspect of "Ok, you have detected methane release from melting permafrost, what are you going to do about it?" Capping a leaking oilhead is fairly straightforward. What are you going to do about arctic warming other than the generalized fight against global warming that these projects are already doing?
The OP touches on the question of "why the focus on plumes and not on tundra or wetlands", and has a quote from Andrew Thorpe hinting at an answer.
>> “These types of emissions are really, really important and very poorly understood,” [Andrew] said. “So I think there’s a heck of a lot of potential to work towards the sectors that have been really hard to do with current technologies.”
I try to keep touch with work in this area. I think it's a combination of SNR and resolution/coverage. The CH4 from a gas leak is very concentrated and so it puts a strong imprint on the spectrum of light passing through it. The natural sources are more diffuse and have less contrast with the surroundings.
(For earlier airborne experiments, the JPL team [which included Andrew] was using a simple matched filter aligned with the methane absorption bands - now they may be using something more complex. This was able to run on a computer on the airplane holding the sensor as it flew over regions of interest.)
Anyway, for sources with a lower CH4 concentration, there will be a much weaker spectral signature. It will be hard to distinguish from other influencers like water, aerosols/dust, etc., or from instrumental effects that may be correlated with location. (E.g., "sometimes high water concentration has spectral effects that appear as high CH4 concentration, so our CH4 values over moist areas are sometimes too high.")
You can improve the effective SNR by accumulating results over a larger area (of space or time). As noted in OP, the ability to get large-area, frequent coverage is quite new.
And also, CH4 moves, so to combine measurements taken at different times, you need to account for transport. This is the difference between measuring "concentration" (a quantity we're more-or-less directly measuring) and "flux" (an emission rate over time, which we don't get to measure directly).
As noted in OP, the plumes were a low-hanging fruit (or as they say, a fruit lying on the ground. ;-)
12 years after eliminating the biggest part of human made methane emissions, we could see significant cooling effects, possibly helping to prevent tipping points.
I get that methane has a strong greenhouse effect, and that climate models need to account for its concentration to make accurate predictions. But in terms of climate activism, isn't worrying about methane mostly a red herring?
My understanding is that it only stays in the atmosphere for 12 years or so. It doesn't accumulate over centuries the way CO2 does. This means even if we manage to permanently reduce the amount of methane in the atmosphere, it would only be a one-time effect equivalent to not emitting a certain amount of CO2 once. In the long run, the amount of net carbon added to or removed from the carbon cycle, for example from fossil reservoirs, is the only thing that really matters.
That's a misunderstanding. The methane stays in the atmosphere a few years until it reacts with oxygen to CO2. So first you have the multiple times worse effect of CH4 and then you're left with CO2, which is still a greenhouse gas. You're left with CO2 either way, even when you burn the methane. That's why it's so bad. And that's why actually when companies or politicians tell you about "clean" gas, it's very misleading. There is significant leakage in production, transport and storage, before the gas even reaches a consumer.
> So first you have the multiple times worse effect of CH4 and then you're left with CO2, which is still a greenhouse gas.
In case anyone else was wondering, the EPA[1] puts a layman figure on that notional multiple:
>> Methane's lifetime in the atmosphere is much shorter than carbon dioxide (CO2), but CH4 is more efficient at trapping radiation than CO2. Pound for pound, the comparative impact of CH4 is 28 times greater than CO2 over a 100-year period.
But note that at the end of that century, the CO2 is still there and will continue to heat the atmosphere indefinitely. We really need to stop adding carbon to the cycle; optimizing the form of that carbon can only ever be a secondary goal.
> optimizing the form of that carbon can only ever be a secondary goal.
If I may be permitted to reiterate: 28x GWP impact factor. Cherry-picking CH4 is hardly premature optimization...it's pure low-hanging fruit!
Consider this paper published in Nature Communications[1] which analyzed CH4 emissions from just low production natural gas well sites in the US. From the abstract:
>> Here, we integrate national site-level O&G production data and previously reported site-level CH4 measurement data (n = 240) and find that low production well sites are a disproportionately large source of US O&G well site CH4 emissions, emitting more than 4 (95% confidence interval: 3—6) teragrams, 50% more than the total CH4 emissions from the Permian Basin, one of the world’s largest O&G producing regions. We estimate low production well sites represent roughly half (37—75%) of all O&G well site CH4 emissions, and a production-normalized CH4 loss rate of more than 10%—a factor of 6—12 times higher than the mean CH4 loss rate of 1.5% for all O&G well sites in the US.
...and further into the paper:
>> At low production well sites, field observations report a common theme revolving around the issue of well site equipment negligence and disrepair as the primary driver of CH4 emissions. Most proximately, recent work by Deighton et al. documents several of these maintenance-related issues, including, for example, (i) leaks at fittings and joints, (ii) leaks and vents from rusted pump jacks, tanks, and other onsite gathering infrastructure, and (iii) evidence of well site neglect or poor maintenance, such as wellheads or casings covered in weeds or fallen trees.
In summary, an estimated 4 teragrams (4 million metric tons) annual CH4 leakage as a direct consequence of operations/maintenance negligence in just the US. Scaled by 28x GWP factor and now we're in the ballpark of 112 million metric tons CO2 equivalence.
Sounds like a big number, but I need a more relatable proxy to square that figure. This source[2] suggests a typical adult human generates 0.9 kg CO2 per day just breathing. Therefore, the value prop of dropping the penal hammer hard on negligent US low production natural gas site operators implies a CO2 sequestration equivalence of offing 341 million warm adult human bodies...effectively the entire US population! Apologies for the morbid anolog, but it's perhaps much easier to internalize impact by this measure.
Only a secondary goal? Sorry, the notion doesn't pass this layman's ballpark sniff test.
The "short-term" effect on warming is quite severe and very relevant. Also, while carbon atoms are conserved, methane is not. You can make a lot of methane from biomass without needing to absorb methane to produce the biomass.
Accelerating the "natural" cycle is bad even if there is no net increase. A massive forest fire technically doesn't cause any net increase in CO2, but releasing that much CO2 at once causes a lot of problems that wouldn't happen if the same amount were released over hundreds of years as those trees died and decayed.
I'm sure some people would argue that burning oil and gas isn't a net increase either, because all of that carbon came from the atmosphere originally. The important question is what emissions will make life worse for humanity, and what can be done to avoid them. Avoidable methane emissions cause real-world problems regardless of their source.
> the question is still whether that carbon came from a fossil source or was part of the cycle to begin with.
I don't think that matters anymore. At some point, we wanted to reduce atmospheric CO2 to a tolerable level and an obvious approach was to not add to natural emissions.
Now we just need to reduce CO2 in the atmosphere. It doesn't do different things based on its source. If we can reduce it by cutting gas production or by cutting some natural source, we should do it.
In your thought experiment the number of extant cows is a variable determined by human behavior as opposed to inherent regulation. There might be historical population numbers from specific regions where carbon was in equilibrium but that's certainly not where we're at today nor is it a goal of ours.
I think we're only able see some carbon sources as "outside the cycle" due to our infinitesimal lifespans.
That’s exactly why it’s also worth targeting. Its short residence time means that addressing methane emissions could make a meaningful impact. It’s not zero sum - we should address the low hanging fruit of methane emissions while also decarbonizing.
You can also repurpose oil and gas industry people and equipment as part of this work (the Inflation Reduction Act appropriated funds for this). This provides a graceful rolloff for these folks and the industry as oil for energy is sunset.
There is a project to get transcontinental ships to add emitters of FeCl3 to their exhaust stacks, to catalyze oxidation of methane. It seems to be getting enthusiastic uptake from shipowners for reasons unknown to me. 10,000 ships emitting 100kg a day would be enough to bring atmospheric methane in line.
(Fe seeded to the ocean surface is negligible. This is not a thing to trigger algae production.)
It might if companies sell carbon credits based on methane reduction, but that's an argument against the credits not against the actual mitigation action.
I think the idea is even in those 12 years, it's way more damaging than CO2 will be. Over 100 years, it is 28 times more damaging than C02, despite not being in the atmosphere for most of that time.
Plus doesn't it just break down into CO2 anyway, meaning that methane does its direct damage, plus creates more CO2.
It only creates "more CO2" if the carbon atom wasn't part of the carbon cycle to begin with. That's the case for natural gas, but not for biological sources.
I think this is like saying "my car payments are $1000 per month for the next 10 years, and my rent is $30 per month for the next 80 years. For my financial health, why am I worried about the car payment when I will be paying rent for the rest of my life and the car payments will be over relatively soon?" The answer to that is the situation might not work out well.. If you have a total lifetime budget of $150k, then those car payments are devastating and you would be bankrupt before those 80 years are over.
A kicker, who is to say that methane emissions are one time - and are not themselves increasing and also ongoing?
The analogy is not quite exact, since the "rent payment" is more akin to be on the order of 200 years or so (and not just the one human lifetime), but hopefully it makes the point.
Last, my understanding of the climate science is that we are very worried about getting through even the next 100 years. To explain, there is a window of time that is almost closed where drastic action can arrest further drastic rates of change in climate (by drastic rates, I'm speaking to 1 to 2 degrees C of warming within that time). It is important therefore we get a handle of this problem sooner rather than later (compare us (humans) "fixing" the methane problem 5 years from now compared to 30 years from now). Also keep in mind there are feedback loops that would be irreversible once triggered.
If you're going to post quite sensationalist speculation please at least provide some attempt at a source or rationale. It doesn't really pass the sniff test that any goverment would bother with this banal subterfuge when they are more than capable of putting secret payloads into orbit, and have done so many times[1].
There was Zuma, the classified satellite that officially failed to separate from the payload adapter and burned up in the atmosphere but was widely speculated to be a successful test of stealth satellite technology, with the satellite successfully reaching orbit and going dark. A lot of talk about us knowing very little, but everyone loved to show off this graphic from a stealth satellite patent [1]. Of course if the NRO does a good job and the technology works we will never know that it does.
“Many” seems to mean only a dozen-odd. Which seems like an awfully small number to image the entire earth at meaningful levels of resolution or frequency.
Which also seems to be the article’s lesson.
FWIW, it looks like Starlink alone is up to 5,942 satellites in orbit [0] these days
> it looks like Starlink alone is up to 5,942 satellites in orbit [0] these days
Starlink operates by far the largest constellation of satellites. Definitely the largest commercial constellation. That's like saying Google "just" serves ~8.5bn search queries/day. I might be mistaking your implication tho.
the field of view from LEO (for Starlink) is so much smaller than from GEO. I'm not sure what the orbit is for the methane satellites, but the number of satellites alone isn't the only factor.
If SpaceX cared, the Starlink fleet (both satellites and ground stations) could be the biggest, most sensitive radio telescope in the world, without compromising its usefulness as a network. It points in all directions at the same time. With such sensitivity, a very short "exposure" time is plenty.
Each node records a few cycles of analog waveform at a certain atomic-clock time determined by its position, and forwards that to a common collection point to correlate with the others.
The Starlink satellite antennas all point at the Earth. The antennas are also small compared to radio telescopes. They also listen to specific frequencies. They would make the best radio telescope for detecting Starlink customers.
The customer antennas would make poor radio telescope because the antennas are small. If using array of small antennas as radio telescopes were possible, we would see them. Using interferometry requires measuring positions and times to sub-wavelength. The Square Kilometer Array is the closest, but it is small extent, with large dishes, and many low-frequency antennas.
The post goes into details about coverage vs. resolution and shows you the data from the satellites and your first thought is that it's all a big lie/coverup?
I would guess for the same reason the government consistently buys $1000 hammers and $5000 toilet seats - to mask some military operation theyd rather not publicly report on.
[1]https://www.nature.com/articles/d41586-024-00600-z
[2]https://www.methanesat.org/satellite/
[3]https://www.iea.org/reports/global-methane-tracker-2022/meth...