Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomie podcast. Each episode offers a
Speaker 1: gentle journey through the stars, planets, and beyond, perfect for
Speaker 1: unwinding after a long day. Let's travel through the mysteries
Speaker 1: of the universe as you drift off into a peaceful
Speaker 1: slumber under the night sky.
Speaker 2: I want you to try something with me. It's a
Speaker 2: mental exercise to get us started. Okay, I want you
Speaker 2: to close your eyes right now, just for a second.
Speaker 2: Imagine you are standing in the middle of a vast
Speaker 2: open field, right You are miles away from the nearest city,
Speaker 2: no street lights, no car headlights, just total absolute darkness.
Speaker 3: And you look up bicks classic night sky, the one
Speaker 3: our ancestors saw exactly. Yeah.
Speaker 2: For ninety nine percent of human history, that view was static.
Speaker 2: It was peaceful.
Speaker 3: It was empty, Yeah, predictable.
Speaker 2: You had the stars, the planets, the Milky Way if
Speaker 2: you were lucky enough to be away from light pollution.
Speaker 2: It was a painting that didn't change. It was the
Speaker 2: definition of stillness.
Speaker 3: But now now it's different.
Speaker 2: Open your eyes because that painting is gone.
Speaker 3: It has been replaced by a highway.
Speaker 2: That's a great way to put it. If you go
Speaker 2: out tonight and you have the right equipment, or honestly,
Speaker 2: even if you just have decent eyesight and look closely
Speaker 2: during twilight, that sky is buzzing.
Speaker 3: It really is.
Speaker 2: It is literally alive with movement. It's not just shooting
Speaker 2: stars anymore. It's hardware. It is human made machinery streaking
Speaker 2: across the constellations.
Speaker 3: It is infrastructure. That is the fundamental shift. Yeah, we
Speaker 3: used to look up and see nature, you know, something eternal.
Speaker 3: Now we look up and see traffic.
Speaker 2: And today is Monday, February sixteenth, twenty twenty six. And
Speaker 2: as we sit here right now, the sheer volume of
Speaker 2: metal circling over our heads is well, it's staggering.
Speaker 3: It is. It's hard to comprehend just how busy it
Speaker 3: has gotten in such a short amount of time.
Speaker 2: So let's put a number on it.
Speaker 3: To put a specific number on it. As of this morning,
Speaker 3: there are roughly eleven thousand, eight hundred active satellites in orbit.
Speaker 2: Eleven thousand, eight hundred, just you know, pause on that
Speaker 2: for a second. Nearly twelve thousand distinct machines flying at
Speaker 2: seventeen thousand miles per hour weaving around each other.
Speaker 3: And that number, that eleven thousand, eight hundred, that's just
Speaker 3: the active ones. That doesn't even count the dead ones.
Speaker 3: The old rocket stage is the debris.
Speaker 2: Oh wow, Okay, so the actual number of objects is
Speaker 2: much higher, much much higher. That's already hard for me
Speaker 2: to wrap my head around. I remember when it was
Speaker 2: just a few hundred. But when I looked at the
Speaker 2: projections in the source material for today's analysis, that is
Speaker 2: when I actually got worried.
Speaker 3: You are looking at the twenty thirty numbers, I am,
Speaker 3: and they are.
Speaker 2: I mean, they're exponentially wilder.
Speaker 3: They are. The current industry predition suggests that by the
Speaker 3: end of this decade, so effectively, in just four years,
Speaker 3: that number isn't going to double, it isn't going to triple.
Speaker 3: It could skyrocket to over one hundred thousand satellites.
Speaker 2: One hundred thousand. That isn't a highway anymore. No, that
Speaker 2: is a swarm. That is a cloud of metal encasing
Speaker 2: the planet. And this brings us to the absolute heart
Speaker 2: of what we are unpacking today, because there's a tension here,
Speaker 2: a conflict that I think most people, even those who
Speaker 2: follow space news don't fully realize is happening.
Speaker 3: It is the central tension of the modern space age.
Speaker 3: It is what researchers are now calling the space sustainability.
Speaker 2: Paradox, the paradox, and this is the hook for today's
Speaker 2: exploration because on one hand, we are launching all of
Speaker 2: these satellites for noble reasons right for most part, Yes,
Speaker 2: we aren't just doing it for TikTok or high frequency trading.
Speaker 2: We are trying to save Earth. We are monitoring climate change,
Speaker 2: we are watching crops to ensure food security, we are
Speaker 2: tracking disasters.
Speaker 3: Precisely, we are building a nervous system for the planet.
Speaker 3: We are trying to give Earth away to sense itself,
Speaker 3: to monitor its own vital signs.
Speaker 2: But here is the kicker, the irony. Yeah, in doing so,
Speaker 2: in trying to save the environment down here, we might
Speaker 2: be destroying the environment immediately surrounding Earth.
Speaker 3: That is the core of the paradox. It is a
Speaker 3: concept that has been heavily highlighted by researcher John McIntosh
Speaker 3: and his team at the University of Manchester. The argument
Speaker 3: is that the very tools we are using to solve
Speaker 3: environmental and social challenges on Earth could ultimately undermine the
Speaker 3: long term sustainability of space itself.
Speaker 2: It is a cruel irony, isn't it. We are so
Speaker 2: focused on cleaning up the ground that we are trashing
Speaker 2: the ceiling.
Speaker 3: That is a very apt way to put it. And
Speaker 3: the danger is that if we aren't careful, that ceiling
Speaker 3: becomes unusable.
Speaker 2: And if that happens, and if the.
Speaker 3: Ceiling becomes unusable, we lose the ability to monitor the ground.
Speaker 3: It is a feedback loop of failure. If we break space,
Speaker 3: we lose the tools we need to fix Earth.
Speaker 2: So the mission for this analysis is to look at
Speaker 2: a new breakthrough that might actually help us solve this paradox.
Speaker 2: We are looking at research coming out of the University
Speaker 2: of Manchester that proposes a way to keep an eye
Speaker 2: on our planet without turning low Earth orbit into a
Speaker 2: demolition derby.
Speaker 3: It's a fascinating piece of work because challenge is how
Speaker 3: we have traditionally built satellites. It asks us to rethink
Speaker 3: the trade offs between what we want to see on
Speaker 3: the ground and the risks we take in the sky.
Speaker 2: It seems to ask a pretty fundamental question.
Speaker 3: It does. It forces us to ask, is the way
Speaker 3: we have been designing these missions actually the dangerous part.
Speaker 2: And just a note for everyone listening, we are going
Speaker 2: to get into the weeds of this. We aren't just
Speaker 2: going to skim the surface. We are going to look
Speaker 2: at the physics, the decision making models, and the surprising
Speaker 2: finding is about where the most dangerous places in orbit
Speaker 2: actually are. And spoiler alert because spoiler alert, it is
Speaker 2: not where you think it is.
Speaker 3: It certainly surprised me. The data is very counterintuitive. It
Speaker 3: challenges a lot of the assumptions even industry veterans have
Speaker 3: held for years.
Speaker 2: So let's get into it. Let's start with the basics.
Speaker 2: The crowded sky. Why and I mean really, why are
Speaker 2: we putting one hundred thousand things up there? Is this
Speaker 2: just so I can have faster Internet on my phone?
Speaker 2: Is it just about Starlink and Amazon Kuyper battling for dominance?
Speaker 3: Well, internet connectivity is a big driver. Certainly, the mega
Speaker 3: constellations for broadband are the ones that get the headlines
Speaker 3: because they launch in batches of sixty at a time.
Speaker 2: It's flashy, right, you see the rocket go up, you
Speaker 2: see the videos of them deploying.
Speaker 3: But for this specific discussion and for the research, we
Speaker 3: are analyzing today, the focus is really on Earth observation.
Speaker 2: Satellites Earth observations, so cameras in the sky spying.
Speaker 3: Well, monitoring is the polite term, but essentially yes. However,
Speaker 3: it is much more than just taking pretty pictures or
Speaker 3: military spying. These satellites have become the critical tools for
Speaker 3: meeting the United nations seventeen Sustainable Development Goals or SDGs.
Speaker 2: The SDGs, okay, those are the big global checklists for
Speaker 2: a better world, right, zero hunger, climate action, life on land.
Speaker 3: That's them.
Speaker 2: I see the colorful icons everywhere, but I rarely connect
Speaker 2: them to space hardware.
Speaker 3: You should, because you cannot fix what you cannot measure.
Speaker 3: That is the fundamental rule of engineering in policy. If
Speaker 3: you want to solve zero hunger, you need to know
Speaker 3: where the food is growing, where it is failing, and why.
Speaker 3: That is where these satellites come in. They provide the raw,
Speaker 3: unvarnished data we need to verify if we are actually
Speaker 3: meeting those goals.
Speaker 2: Can we get specific here? I want to visualize this.
Speaker 2: When you say monitoring, what are they actually looking at?
Speaker 2: Give me a concrete example. Let's take one of the goals.
Speaker 3: Okay, let's take land use in urban development. This is
Speaker 3: STG eleven Sustainable Cities and Communities. Okay, right now, cities
Speaker 3: in the global South are expanding at a rate that
Speaker 3: is almost impossible to track from the ground. You have
Speaker 3: informal settlements, slums popping up overnight.
Speaker 2: And governments might not even know they're there.
Speaker 3: They don't have the paperwork exactly, they don't have the
Speaker 3: census data, they don't have the resources to send surveyors
Speaker 3: out every week. But a satellite passes over every day.
Speaker 2: Every single day. It sees the.
Speaker 3: New roofs, It sees the roads being cut into the forest,
Speaker 3: It sees where the infrastructure is failing. It can measure
Speaker 3: the heat island effect of a specific neighborhood. We use
Speaker 3: that data for real time urban planning on a planetary.
Speaker 2: Scale, so it isn't just a map. It is a
Speaker 2: living document of human expansion. It helps them figure out
Speaker 2: where to put water pipes or schools or clinics correct.
Speaker 3: It turns urban planning from a reactive process into a
Speaker 3: proactive one. Then look at environmental degradation. This is the
Speaker 3: big one.
Speaker 2: Climate action, life on land, life below water, all of.
Speaker 3: That, all of it. We are tracking deforestation in the
Speaker 3: Amazon counting the trees as they fall. We are measuring
Speaker 3: the volume of melting ice sheets in the Arctic to
Speaker 3: the cubic meter.
Speaker 2: How is that even possible?
Speaker 3: Using radar altimetry, they bounce signals off the ice and
Speaker 3: measure the return time down to the nanosecond. That tells
Speaker 3: you the height of the ice sheet and you can
Speaker 3: see it shrinking over time.
Speaker 2: That's incredible.
Speaker 3: We are monitoring the health of coral reefs by looking
Speaker 3: at the color of the water. We can even track
Speaker 3: illegal fishing boats by spotting ships that have turned off
Speaker 3: their transponders.
Speaker 2: So it's accountability.
Speaker 3: It's accountability and its measurement. You can have a climate
Speaker 3: treaty if you can't verify if a country is actually
Speaker 3: reduced seeing its emissions or protecting its forests. This is
Speaker 3: the verification system.
Speaker 2: And disaster response is a huge one too. I remember
Speaker 2: reading about this during the last big earthquake season.
Speaker 3: It is critical. It's one of the most immediate life
Speaker 3: saving applications. When an earthquake hits or a hurricane makes landfall,
Speaker 3: the roads are gone, the power lines are.
Speaker 2: Down, chaos on the ground.
Speaker 3: You cannot send a guy in a jeep to check
Speaker 3: the damage. The first thing emergency responders ask for is
Speaker 3: the satellite.
Speaker 2: Pass They need the before and after photo to see
Speaker 2: where help is needed.
Speaker 3: They need a damage map. They need to know which
Speaker 3: bridges are out, which neighborhoods are underwater. That coordination of
Speaker 3: aid getting the water and medicine to the right place
Speaker 3: in the first twenty four hours saves one thousands of lives. Wow,
Speaker 3: And that coordination happens because of eyes in the sky.
Speaker 2: It connects back to food security too, doesn't it the
Speaker 2: zero hunger goal?
Speaker 3: It does. This is arguably the most sophisticated usage. We
Speaker 3: aren't just taking photos of corn fields to count the acres.
Speaker 3: More than that, oh much more. We were using hyper
Speaker 3: spectral imaging. We look at wavelengths of light that the
Speaker 3: human eye cannot see.
Speaker 2: What does that tell you?
Speaker 3: It tells you everything. We can look at the moisture
Speaker 3: levels inside the soil. From orbit. We can see the
Speaker 3: chlorophyll content in the leaves, which tells you how healthy
Speaker 3: the plant is.
Speaker 2: So you can spot a blight or a drought before
Speaker 2: it's visible to a farmer on the ground.
Speaker 3: Exactly. We can predict a yield shortage in wheat across
Speaker 3: the entire Ukrainian bread basket months before the harvest actually happens.
Speaker 2: That is incredible. So in a world with a growing
Speaker 2: population and a climate that is getting more erratic, that
Speaker 2: data is essentially preventing famine.
Speaker 3: It is.
Speaker 2: It tells governments, hey, you were going to run out
Speaker 2: of food in six months by grain now exactly.
Speaker 3: It smooths out the shocks to the global food system.
Speaker 3: And speaking of shocks, the sources also mentioned supply chains.
Speaker 2: Ah, yes, remember.
Speaker 3: They ever given the ship that blocked the Sioux Is Canal.
Speaker 2: Hard to forget the meme of the year.
Speaker 3: Satellites were tracking that backup in real time. If you
Speaker 3: can see that a port in Shanghai is congested or
Speaker 3: a key route is blocked, you can anticipate economic shocks.
Speaker 3: You could reroute cargo. It's the backbone of global logistics. Okay,
Speaker 3: So when we talk about these one hundred thousand satellites,
Speaker 3: we have to be clear. We aren't just throwing them
Speaker 3: up there for fun. No, we aren't just doing it
Speaker 3: because we can. We rely on them. They are the
Speaker 3: nervous system of our modern civilization.
Speaker 2: They really are. If you turn them off tomorrow, we
Speaker 2: would be flying blind on climate, on agriculture, on disaster relief.
Speaker 3: We would be back to the nineteen fifties in terms
Speaker 3: of our situational awareness.
Speaker 2: We would be reacting to disasters after they happen instead
Speaker 2: of seeing them coming.
Speaker 3: Okay, so we have established the stakes. The why is solid.
Speaker 3: We need the data. But and here's the massive butt
Speaker 3: we teased earlier, there is a cost of doing business.
Speaker 2: There is always a cost. Physics demands a trade off.
Speaker 3: The rapid growth of these missions is making Earth's orbits,
Speaker 3: specifically low Earth orbit or LEO crowdod and hazardous.
Speaker 2: Hazardous is a polay way of putting it. It is
Speaker 2: becoming a minefield. Break that down for me. When we
Speaker 2: say hazardous, are we talking about traffic jams? Like are
Speaker 2: satellites waiting at a red light?
Speaker 3: That's Jim chuckles. I wish it were that simple. No,
Speaker 3: imagine a highway. But on this highway, everyone is driving
Speaker 3: at seventeen thousand miles per hour. Okay, that is the
Speaker 3: speed required to stay in orbit. If you slow down,
Speaker 3: you fall out of the sky. So you have to
Speaker 3: go fast.
Speaker 2: Seventeen thousand miles power That is what ten times faster.
Speaker 3: Than a bullet roughly, Yes, and on this highway there
Speaker 3: are no lanes, there are no stop signs, there is
Speaker 3: no air traffic control telling you to turn left or
Speaker 3: right in real time, and no breaks and no breaks,
Speaker 3: And crucially, occasionally a car just falls apart and leaves
Speaker 3: its bumper in the middle of the road.
Speaker 2: And because there is no air drag to slow it down,
Speaker 2: that bumper just keeps flying at seventeen thousand miles per hour.
Speaker 3: Precisely, it stays there for years, maybe decades, maybe centuries,
Speaker 3: depending on the altitude. That is the threat of space debris.
Speaker 2: So even some thing tiny is a problem in space.
Speaker 3: A collision is catastrophic. It is an a fendobender where
Speaker 3: you pull over an exchange insurance info.
Speaker 2: It's his total annihilation.
Speaker 3: When two satellites collide, or when a satellite hits a
Speaker 3: piece of debris the size of a marble, it doesn't
Speaker 3: just dent. The kinetic energy involved is insane, right the physics,
Speaker 3: remember your high school physics. Kinetic energy equals one half
Speaker 3: mass times velocity squared. When the velocity is seventeen thousand
Speaker 3: miles per hour, that v squared term is enormous. So
Speaker 3: even a tiny mass hits with the force of a
Speaker 3: hand grenade.
Speaker 2: A hand grenade that obliterates.
Speaker 3: The object and creates a cloud of thousands of new fragments.
Speaker 2: Which then go on to hit other things. This is
Speaker 2: the Kessler syndrome, right, the runaway chain reaction.
Speaker 3: That is the worst case scenario, the domino effect. One
Speaker 3: collision creates debris, which causes two collisions, which creates more
Speaker 3: debris until the entire orbit is ground into dust. It
Speaker 3: creates a shell of shrapnel around the Earth.
Speaker 2: And if that happens.
Speaker 3: If that happens, we lose space. We cannot launch through
Speaker 3: that cloud. We lose GPS, we lose the weather satellites,
Speaker 3: we lose the climate monitoring. We are trapped on earth
Speaker 3: that is terrifying.
Speaker 2: So by trying to monitor the earth to save it,
Speaker 2: we are clogging up the viewpoint we need to do
Speaker 2: the monitoring.
Speaker 3: That is the space sustainability paradox. In a nutshell, we
Speaker 3: are risking the very environment we need to utilize.
Speaker 2: Okay, so we have established the stakes. We need the data,
Speaker 2: but getting the data is risky. Now let's talk about
Speaker 2: why this is happening. Is it just that we are
Speaker 2: launching too many or is there a flaw in how
Speaker 2: we are designing these things.
Speaker 3: It is a bit of both. But the research in
Speaker 3: the University of Manchester highlights a fundamental flaw in the
Speaker 3: traditional design process, a flaw in the thinking exactly. It
Speaker 3: suggests we've been doing the engineering backwards.
Speaker 2: How does it usually work? If I am an engineer
Speaker 2: at a big aerospace company Lockheed Boeing Airbus, and I
Speaker 2: am told to build a new climate satellite, what is
Speaker 2: my process?
Speaker 3: Traditionally there is a disconnect, a siloed approach. You start
Speaker 3: with mission requirements. Okay, your client comes to you, maybe
Speaker 3: it's a government, maybe it does a company and says
Speaker 3: I need to see a car on the ground in Tokyo,
Speaker 3: or I need to measure the ice in Antarctica and
Speaker 3: I need the data back to headquarters in under ten minutes.
Speaker 2: So you focus on the payload, the camera, the antenna,
Speaker 2: the power exactly.
Speaker 3: You design the payload to meet those needs. Can we
Speaker 3: get the data? Is the resolution high enough? Is the
Speaker 3: bandwidth fast enough? That is the priority. That is what
Speaker 3: you get paid for. That is the success criteria for
Speaker 3: the mission.
Speaker 2: And safety? Where does safety fit?
Speaker 3: In collision? Risk assessment often happens separately or critically it
Speaker 3: happens too late in the development.
Speaker 2: Process, so it's an afterthought.
Speaker 3: It is treated as a regulatory box to check. You
Speaker 3: build the satellite to do the job, you decide where
Speaker 3: it needs to fly to get the pictures, and then
Speaker 3: you check, oh, is this orbit safe.
Speaker 2: It is like designing a sports car that can go
Speaker 2: two hundred miles per hour, building the engine, the chassis,
Speaker 2: the wheels, and then realizing at the very end, oh, wait,
Speaker 2: this thing has no brakes and we are driving on ice.
Speaker 3: That is a surprisingly accurate analogy. You have locked in
Speaker 3: the design parameters, the size, the mass, the orbit before
Speaker 3: you have really calculated the long term risk to the.
Speaker 2: Environment, and at that point it's too late to change it.
Speaker 3: Well, it is often too expensive to redesign the whole bird,
Speaker 3: so you might tweak the orbit slightly, but largely you'll
Speaker 3: launch anyway and hope for the best.
Speaker 2: And that brings us to the innovation we are analyzing today,
Speaker 2: this new research published in Advances in Space Research. Who
Speaker 2: are the brains behind.
Speaker 3: This The team is from the University of Manchester. You
Speaker 3: have the lead author, John McIntosh, who is a PhD
Speaker 3: researcher doing some really cutting edge work. Then there is
Speaker 3: doctor CERR McGrath, a lecturer in aerospace systems, and Professor
Speaker 3: Catherine Smith, a professor of space technology.
Speaker 2: A solid lineup academics, but with a focus on systems
Speaker 2: engineering practical application.
Speaker 3: Very much so. And what exactly have they built is
Speaker 3: not a new type of shield. It's not a to zapp.
Speaker 2: Debriathe right, It's not a physical thing.
Speaker 3: No, it is something much more boring and much more important.
Speaker 3: They have developed a new modeling framework.
Speaker 2: Okay, hold on, modeling framework sounds like jargon. What does
Speaker 2: that actually mean? In plain English?
Speaker 3: It means they built a simulator, a decision making tool.
Speaker 3: The key breakthrough here is that it links mission objectives
Speaker 3: directly with collision risk as a key first step in
Speaker 3: mission design.
Speaker 2: So before they even draw the blueprint, before they cut
Speaker 2: a single piece of metal, they are calculating the risk.
Speaker 3: Yes, instead of treating safety as an afterthought.
Speaker 2: It's a core design parameter.
Speaker 3: It treats safety in image quality as interconnected variables. You
Speaker 3: cannot change one without affecting the other. It forces the
Speaker 3: engineer to see the consequences of their design choices immediately.
Speaker 2: This sounds like it should have been obvious, but I
Speaker 2: guess when you are in a gold rush, you don't
Speaker 2: think about the dust you are kicking up.
Speaker 3: It is a shift in mindset. It moves from performance
Speaker 3: first to sustainable performance, and that is a huge lead
Speaker 3: for the industry.
Speaker 2: I want to get under the hood of this model.
Speaker 2: They call it a framework, but I want to visualize it.
Speaker 2: How does it actually work? What connects a picture of
Speaker 2: a cornfield in Iowa to a collision in space? Because
Speaker 2: those feel like two very different problems.
Speaker 3: To understand that, we have to look at what I
Speaker 3: like to call the iron triangle of orbit. The model
Speaker 3: breaks down several inputs that are all mathematically linked. First,
Speaker 3: you have image resolution.
Speaker 2: This is the quality of the camera, the sharpness of
Speaker 2: the picture. Right.
Speaker 3: How clear does the picture need to be? Do I
Speaker 3: need to see the cornfield as a green blur? Or
Speaker 3: do I need to see the individual stocks of corn.
Speaker 2: High resolution versus low resolution?
Speaker 3: Exactly? In the study they use an example of ero
Speaker 3: point five meters. That is the ground sampling distance. It
Speaker 3: means each pixel in the digital image represents half a
Speaker 3: meter on the ground.
Speaker 2: That is sharp. That is sharp enough to see cars,
Speaker 2: small structures, agricultural lines.
Speaker 3: You could count the tents in a refugee camp.
Speaker 2: With that, you could probably tell what kind of car
Speaker 2: it is, but not the license plate.
Speaker 3: That's a good way to think about it is the
Speaker 3: standard for high quality commercial observation. So that is input one.
Speaker 2: Okay, what else goes into the simulator?
Speaker 3: Coverage? How much of the Earth that we need to see?
Speaker 3: And how often do you need a global map every
Speaker 3: single day, every hour or just once a month? So
Speaker 3: the revisit rate, the revisit rate exactly. This determines how
Speaker 3: many satellites you need in your constellation.
Speaker 2: Got it, frequency and scope.
Speaker 3: Then you have the satellite physicality, the size and the
Speaker 3: mass of the actual machine. How big is it, how
Speaker 3: heavy is it? And finally the debris density of the
Speaker 3: neighborhood you want to fly in, So how much junk
Speaker 3: is already in that specific orbital shell.
Speaker 2: Okay, So we have all these variables resolution, coverage, size, debris.
Speaker 2: How do they interact? Because this is where the physics
Speaker 2: of optics comes in, right, And I feel like this
Speaker 2: is where the trade offs get really tricky.
Speaker 3: This is the crux of the problem. This is where
Speaker 3: the Manchester team really showed their work. Let's say you
Speaker 3: are the engineer. You have a requirement. You need that
Speaker 3: point five meter resolution image. You cannot compromise on that.
Speaker 2: Okay, I need the sharp photo. That is my job,
Speaker 2: non negotiable.
Speaker 3: We have two main options to get it. Option A
Speaker 3: you fly low.
Speaker 2: The low option you get closer to the subject. Makes sense, right, If.
Speaker 3: You are closer to the ground, say at three hundred
Speaker 3: or four hundred kilometers altitude, you can use a smaller
Speaker 3: camera to get a sharp image. Think about it, like
Speaker 3: holding your phone camera close to a piece of paper.
Speaker 3: You can see the details easily.
Speaker 2: Okay, So smaller camera means.
Speaker 3: A smaller satellite, a smaller lens, a smaller body, lighter
Speaker 3: launch weight, cheaper.
Speaker 2: Okay, benefit, clear picture, smaller satellite, cheaper launch. What is
Speaker 2: the drawback? There's always a drawback.
Speaker 3: The drawback is your field of view. Because you are
Speaker 3: so close, you are only seeing a tiny patch of
Speaker 3: the earth at any one moment.
Speaker 2: It is like looking through a straw.
Speaker 3: Exactly, you are looking through a straw at a giant
Speaker 3: beach ball. You can see the details of one little
Speaker 3: grain of sand, but you cannot see the whole beach ball.
Speaker 3: So if you want to.
Speaker 2: Cover the whole earth, you need a lot of straws.
Speaker 3: You need a massive constellation of satellite to stitch it
Speaker 3: all together, hundreds, maybe thousands of them.
Speaker 2: Okay, so low orbit means small satellites, but lots of
Speaker 2: them a swarm. What is option B?
Speaker 3: Option B you fly high, You go to a higher altitude,
Speaker 3: say eight hundred and nine hundred.
Speaker 2: Kilometers, so you are further away.
Speaker 3: The benefit is you have a much wider field of view.
Speaker 3: You are backing up from the painting, you'd see more
Speaker 3: land at once.
Speaker 2: Right, your straw just got wider.
Speaker 3: It did. That means you need fewer satellites to cover
Speaker 3: the globe.
Speaker 2: That sounds better. Fewer satellites means less traffic.
Speaker 3: Right.
Speaker 2: That sounds like the responsible choice, you would think so.
Speaker 3: But here is the kicker. Here's the trade off. To
Speaker 3: get that same point five meter resolution, that same sharpness
Speaker 3: from twice as far away, you cannot use a small
Speaker 3: camera anymore. Physics bites back it does It is the
Speaker 3: diffraction limit of light. To resolve that detail from nine
Speaker 3: hundred kilometers, you need a massive telescope. You need a
Speaker 3: large aperture to gather enough light and achieve that resolution.
Speaker 2: We are talking hubble size, maybe.
Speaker 3: Not hubble, but big. You need bigger mirrors, longer focal lengths,
Speaker 3: and bigger optics means a bigger satellite body to hold it,
Speaker 3: bigger solar panels to power it. Because it takes more
Speaker 3: energy to transmit the data.
Speaker 2: That far so high orbit means fewer satellites, but they
Speaker 2: are giants. They are buses instead of motorcycle.
Speaker 3: Correct significantly bigger, heavier. And this brings us to the
Speaker 3: critical variable in the Manchester model cross section.
Speaker 2: Cross section that is basically how big of a target
Speaker 2: you are, how much area you present to the incoming traffic.
Speaker 3: Yes, a larger satellite has a larger cross section, It
Speaker 3: takes up more physical space in the void and in
Speaker 3: a minefield of debris. Being big is a liability.
Speaker 2: It is the difference between walking through a hailstorm holding
Speaker 2: a dinner plate over your head versus holding a barn door.
Speaker 3: The barn door is going to get hit. And remember
Speaker 3: we aren't just worried about the satellite getting hit. We're
Speaker 3: worried about the satellite becoming debris.
Speaker 2: Ah. Yes, the aftermath.
Speaker 3: If a five hundred kilogram satellite hits something, it creates
Speaker 3: a massive cloud of shrapnel. If a five kilogram cube
Speaker 3: sat gets hit. It is bad, but it's a much
Speaker 3: smaller cloud.
Speaker 2: This is starting to make sense. The model is balancing
Speaker 2: the number of satellites against the size of the satellites,
Speaker 2: against the altitude. It is a three dimensional balancing act.
Speaker 3: And this is where the findings get really surprising, because
Speaker 3: I think most people, myself included, would assume that the
Speaker 3: most dangerous place to put a satellite is simply wherever
Speaker 3: the most debris.
Speaker 2: Is right avoid the trash. If there is a pile
Speaker 2: in junk at eight hundred kilometers, don't fly at eight
Speaker 2: hundred kilometers. That seems like common sense, like don't drive
Speaker 2: into the pile up.
Speaker 3: But the model reveals a counterintuitive truth. Collision risk does
Speaker 3: not simply peak where debris is most concentrated.
Speaker 2: Okay, unpack that. How can that be true? If there
Speaker 2: are more bullets, shouldn't there be more bullet holes.
Speaker 3: Let's look at the case study they were in. They
Speaker 3: modeled that satellite we talked about, the one designed for
Speaker 3: er point five meter resolution, that ran the numbers for
Speaker 3: different altitudes to see where the risk was highest.
Speaker 2: And what did they find? Where's the danger zone?
Speaker 3: The collision probability was highest between eight hundred and fifty
Speaker 3: and nine hundred and fifty kilometers above Earth.
Speaker 2: Eight hundred and fifty to nine fifty Okay, is that
Speaker 2: where the most debris is.
Speaker 3: No, that is the fascinating part. The peak density of debris,
Speaker 3: the thickest part of the trash cloud is actually about
Speaker 3: fifty kilometers lower than that around eight hundred kilometers.
Speaker 2: Wait, so you were telling me that the satellites are
Speaker 2: more likely to get hit in a region with less debris.
Speaker 2: That sounds impossible. My brain is not computing this.
Speaker 3: It sounds impossible until you factor in the size of
Speaker 3: the satellite.
Speaker 2: Ah.
Speaker 3: Remember the high option to fly at eight hundred fifty
Speaker 3: kilometers and still get that sharp picture, your satellite has
Speaker 3: to be enormous. Ah.
Speaker 2: So, even though the bullets are slightly fewer and further between,
Speaker 2: the target is so much bigger that the math tips.
Speaker 3: Against you precisely. Yeah, you move to a slightly quieter neighborhood,
Speaker 3: but you built a house ten times the size, so
Speaker 3: you are actually more likely to get hit by a
Speaker 3: stray baseball than if you had stayed in the busy
Speaker 3: neighborhood but lived in a tiny shack.
Speaker 2: That is a massive aha moment. It changes everything. You
Speaker 2: cannot just look at a debris map and say safe
Speaker 2: for unsaved.
Speaker 3: Oh, the debris map is only half the story.
Speaker 2: You have to look at your own vehicle, your own
Speaker 2: mission requirements dictate your vulnerability.
Speaker 3: You have to look at the interaction. The sheer size
Speaker 3: of those high altitude satellites makes them what the researchers
Speaker 3: called debris magnets. They sweep up everything in their path
Speaker 3: just by existing.
Speaker 2: Wow. So let's talk about the alternative. Then. If the
Speaker 2: big high flying satellites are debris magnets, does that mean
Speaker 2: the swarm of small, low flying ones is actually safer?
Speaker 3: That is the constellation conundrum, and the model suggests counterintuitively, yes.
Speaker 2: Walk me through that because earlier I said one hundred
Speaker 2: thousand satellites sounds terrifying. How can more satellites be the
Speaker 2: safer option? It just feels wrong.
Speaker 3: It comes down to the physics of the impact and
Speaker 3: the probability in lower orbits, say four hundred kilometers. Yes,
Speaker 3: you need more satellites to cover the Earth because of
Speaker 3: that looking through a straw.
Speaker 2: Effect, right, many small straws.
Speaker 3: But because they are close, they can be small. They
Speaker 3: have small optics, small bodies, tiny targets, and because they
Speaker 3: are tiny targets, the individual collision risk for each state
Speaker 3: is much much lower, and this is crucial. If they
Speaker 3: do collide, they create less debris because there is less
Speaker 3: mass involved.
Speaker 2: So even though there are more of them, the odds
Speaker 2: of any single one of them causing a global disaster
Speaker 2: are smaller and the consequences of a crash are less severe.
Speaker 3: Yes, the study found that despite there being more of them,
Speaker 3: the smaller individual satellites are less hazardous in terms of
Speaker 3: collision probability compared to the massive, high altitude targets.
Speaker 2: That is fascinating. It is a total flip of the script.
Speaker 2: We usually think less is more when it comes to sustainability,
Speaker 2: but here more but smaller might be the responsible choice.
Speaker 3: It allows designers to evaluate trade offs in a nuanced way.
Speaker 3: It is not just about data quality anymore. It is
Speaker 3: about balancing data quality with protecting the orbital environment.
Speaker 2: So an engineer can I go to their boss and say, look,
Speaker 2: I know you want to launch just ten satellites for
Speaker 2: this mission because it's cheaper to operate. But the model
Speaker 2: shows if we launch one hundred smaller ones at a
Speaker 2: lower altitude, the long term risk to the space environment
Speaker 2: drops by eighty percent.
Speaker 3: That is exactly the conversation this tool enables. It proves
Speaker 3: that you cannot just optimize for one variable. You have
Speaker 3: to optimize the whole system for sustainability.
Speaker 2: And this brings us back to the voices behind the study.
Speaker 2: What are they saying about the implications of this, because
Speaker 2: this sounds like it should be mandatory reading for everyone
Speaker 2: at NASA and SpaceX, and well every space agency and
Speaker 2: company on Earth.
Speaker 3: It really should be. Doctor c R McGrath, one of
Speaker 3: the co authors, really emphasize the practicality of this. She said,
Speaker 3: this method offers a practical way to ensure space remains
Speaker 3: safe and usable for generations.
Speaker 2: That word practical is key. This isn't just theoretical physics.
Speaker 2: This isn't just an academic paper to sit on a shelf.
Speaker 2: This is a tool engineers can use tomorrow exactly.
Speaker 3: It's a dashboard. You can slide the dial on resolution
Speaker 3: and see the risk needle go up or down. You
Speaker 3: can change the altitude and watch the constellation size and
Speaker 3: satellite mass numbers change in real time.
Speaker 2: That's powerful.
Speaker 3: It allows us to still get the data we need
Speaker 3: for those global challenges climate food disasters without sacrificing the
Speaker 3: future of space exploration. It gives us a path to
Speaker 3: have our cake and eat.
Speaker 2: It too, and Professor Catherine Smith pointed out that this
Speaker 2: isn't just for one type of satellite, right, It's adaptable right.
Speaker 3: She noted that the method can be adapted for different
Speaker 3: Earth observation systems, whether you were using optical cameras like
Speaker 3: we've been discussing, or something like synthetic aperture RADARSAR which
Speaker 3: can see through clouds.
Speaker 2: Which is critical for monitoring places that are always cloudy,
Speaker 2: like the tropics or the Pole exactly.
Speaker 3: The logic still holds you can plug in your variables
Speaker 3: and see where your risks are. It's a universal toolkit
Speaker 3: for sustainable design.
Speaker 2: So what is next for this model? Is it finished
Speaker 2: or is this just version one point zero?
Speaker 3: Science is never finished. This is definitely version one point zero.
Speaker 3: The Gene plans to expand the model to include even
Speaker 3: more detailed impacts. For example, they want to look at
Speaker 3: how long debrief fragments.
Speaker 2: Stay in orbit, because that changes based on altitude drastically.
Speaker 3: If you are low at four hundred kilometers, there's still
Speaker 3: a tiny bit of atmosphere. That atmospheric drag pulls the
Speaker 3: debris down quickly. It deorbits and burns up in a
Speaker 3: few years.
Speaker 2: So it's self cleaning to a degree.
Speaker 3: It is, but if you are high up at that
Speaker 3: nine hundred kilometer danger zone, there is basically no drag.
Speaker 3: That debris can stay there for centuries millennia.
Speaker 2: Even so, a crash at nine hundred kilometers is a
Speaker 2: permanent scar. A crash at four hundred kilometers is a
Speaker 2: temporary scratch.
Speaker 3: That is a perfect way to put it. And they
Speaker 3: want to model the domino effect, how likely fragments from
Speaker 3: one collision are to hit other satellites.
Speaker 2: The nightmare Kessler syndrome scenario exactly.
Speaker 3: To model how a single bad day could cascade through
Speaker 3: entire constellation. And they also want to look at the
Speaker 3: wider environmental effects of satellite re entry re.
Speaker 2: Entry, that is, when they burn up in the atmosphere
Speaker 2: at the end of their life.
Speaker 3: Yes, and that is a whole other can of worms.
Speaker 2: We will get to that in a minute. I have
Speaker 2: questions about that, but sticking to the model for now.
Speaker 2: The ultimate goal here seems to be giving mission designers
Speaker 2: the full sustainability picture It is.
Speaker 3: About moving from a wild wat mentality of space exploration
Speaker 3: where you just launch whatever you want wherever you want
Speaker 3: to responsible stewardship.
Speaker 2: Responsible stewardship. I like that. It feels like we are
Speaker 2: finally growing up as a spacefaring civilization. We are realizing
Speaker 2: that we cannot just trash the place and move on.
Speaker 3: We have to manage the comments. Space is a shared resource.
Speaker 3: If one company pollutes an orbit, everyone suffers. This model
Speaker 3: gives us the math to prevent that.
Speaker 2: I want to circle back to something we touched on earlier.
Speaker 2: The sheer scale of this one hundred thousand satellites, even
Speaker 2: with this model, even if we design them perfectly, that
Speaker 2: is a lot of traffic.
Speaker 3: It is, and this model doesn't solve the crowding issue entirely.
Speaker 3: It just helps us mitigate the risk of catastrophic collisions.
Speaker 2: It's a risk reduction tool, not a magic wand.
Speaker 3: Exactly, we still have to manage the traffic management aspect.
Speaker 3: We need better tracking of every object, better communication between operators,
Speaker 3: maybe even internationally agreed upon slots for orbits like we
Speaker 3: have for airport gates.
Speaker 2: It is like having a safer cars on the road,
Speaker 2: which is great, but you still have.
Speaker 3: A traffic gem exactly, but at least the cars aren't
Speaker 3: exploding as often.
Speaker 2: That is a start. So let's synthesize what we have
Speaker 2: learned today, because this has been a journey from the
Speaker 2: night sky to the physics lab.
Speaker 3: Let's break it down first.
Speaker 2: The context, we are heading toward a world with one
Speaker 2: hundred thousand active satellites. That is happening. The train has
Speaker 2: left the station.
Speaker 3: And we identify the space sustainability paradox. We are launching
Speaker 3: these machines to solve problems on Earth, critical problems like
Speaker 3: climate change and hunger, but the act of launching them
Speaker 3: creates a new environmental disaster in space.
Speaker 2: Then we looked at the Manchester research. They proved that
Speaker 2: the old way of designing satellites mission first, safety later
Speaker 2: is broken. It's fundamentally flawed. You have to do them together, and.
Speaker 3: We unpack the iron triangle. We learn that to get
Speaker 3: high resolution images you either have to fly low with
Speaker 3: lots of small satellites or fly high with a few
Speaker 3: giant ones. There is no magic cheat code.
Speaker 2: And the counterintuitive finding the real mind vendor. Flying high
Speaker 2: seems safer because there is slightly less debris, but because
Speaker 2: your satellite has to be the size of a bus
Speaker 2: to take a picture, you are actually a bigger target.
Speaker 3: So surprisingly, a constellation of many small satellites in a lower,
Speaker 3: busier orbit might actually be the safer, more responsible choice
Speaker 3: for the orbital environment.
Speaker 2: It really challenges your assumptions. I think that is the
Speaker 2: mark of good science. It makes you look at a
Speaker 2: problem and realize the obvious answer was wrong, and.
Speaker 3: It gives engineers a tool to make better choices. That
Speaker 3: is the most important part. This isn't just philosophy, it
Speaker 3: is engineering. It's a practical solution.
Speaker 2: Now, before we let you go, you mentioned something earlier
Speaker 2: that I want to end on. It's been nagging at me.
Speaker 2: You mentioned satellite re entry as the next frontier for
Speaker 2: this model.
Speaker 3: Yes, this is the final provocative thought I want to
Speaker 3: leave with you and with everyone listening.
Speaker 2: Late on us.
Speaker 3: We spent this whole time talking about collisions in space,
Speaker 3: metal hitting metal debris fields. That is the physical danger.
Speaker 3: But what happens when these satellites die, all one hundred
Speaker 3: thousand of them.
Speaker 2: Eventually they deorbit, they fall back to Earth. We design
Speaker 2: them to burn up so they don't hit someone's house.
Speaker 3: Right, We view burn up as the safe option. It
Speaker 3: burns up, it is gone. But physics tells us matter
Speaker 3: doesn't just disappear.
Speaker 2: Conservation of mass exactly.
Speaker 3: Burn up implies it vanishes. It doesn't. It turns into vapor,
Speaker 3: It turns into dust. It turns into tiny metallic aerosols.
Speaker 3: The metal vapor, aluminum, titanium, lithium, from the batteries, composite materials,
Speaker 3: All of that one hundred thousand satellites are worth of metal.
Speaker 3: Eventually it all rains back down into our upper atmosphere.
Speaker 2: So we are essentially salting the atmosphere with metal dust.
Speaker 3: Exactly, We are changing the chemical composition of the stratosphere,
Speaker 3: and we don't fully know what that does yet.
Speaker 2: That's a terrifying thought.
Speaker 3: Does it affect the ozone layer? Some studies suggest aluminum
Speaker 3: oxides can act as catalysts that deplete ozone. Does it
Speaker 3: change the albedo of the earth. Does it create more
Speaker 3: clouds or different kinds of clouds? Does it reflect sunlight
Speaker 3: or trap heat? Does it affect the climate, So.
Speaker 2: The sustainability paradox might go even deeper. We launch satellites
Speaker 2: to monitor climate change, and when they die, their dust
Speaker 2: might accelerate climate change.
Speaker 3: That is the next great unknown, That is the environmental
Speaker 3: effect of satellite re entry, and that is why the
Speaker 3: Manchester team wants to add it to their model, because
Speaker 3: true sustainability means looking at the entire life cycle from
Speaker 3: the launch pad to the orbit to the burn up.
Speaker 2: That is heavy, but it is important. It means we
Speaker 2: have to keep asking questions. We cannot just pat ourselves
Speaker 2: on the back for solving the collision problem and ignore
Speaker 2: the pollution problem.
Speaker 3: Precisely, there's always another layer to the onion.
Speaker 2: Well, on that cheerful but necessary note, we're going to
Speaker 2: wrap up today's exploration. I want to thank you for listening.
Speaker 3: It has been a pleasure to analyze this with you.
Speaker 2: Next time you are outside at night, look up, try
Speaker 2: to spot a satellite. It is actually pretty easy these days.
Speaker 2: And when you see that little dot moving across the stars,
Speaker 2: remember there is it's a massive amount of math, physics,
Speaker 2: and now hopefully some very smart sustainability modeling keeping it
Speaker 2: from crashing into its neighbor.
Speaker 3: Let's hope.
Speaker 2: So the sky is busier than it looks, but with
Speaker 2: tools like this, maybe we can keep it organized. Thanks
Speaker 2: for joining us on this analysis. Stay curious and keep
Speaker 2: looking up the passa