Speaker 1: Welcome to tech Stuff, a production from I Heart Radio.
Speaker 1: Hey there, and welcome to tech Stuff. I'm your host,
Speaker 1: Jonathan Strickland. I'm an executive producer with I Heart Radio.
Speaker 1: And how the tech are you? You know? Ever since
Speaker 1: the then Soviet Union sent ups foot Nick way back
Speaker 1: in nineteen fifties, seven man made satellites have played a
Speaker 1: really important role in our world in multiple contexts. You know,
Speaker 1: in the early days, at least from a political standpoint,
Speaker 1: it was a lot about demonstrating scientific and engineering superiority.
Speaker 1: That was kind of what was driving the space race,
Speaker 1: at least from a financial and political standpoint, back when
Speaker 1: the US and USS are we're racing to achieve first
Speaker 1: in space. But I mean, obviously they're also important to
Speaker 1: further our scientific under standing of our world and beyond,
Speaker 1: and also to do stuff like layout communications infrastructure that
Speaker 1: would allow for global communication. And of course there are
Speaker 1: thousands of other applications and satellites are really out of
Speaker 1: this world. And yes, I also hate me for saying that,
Speaker 1: And I thought it could be a little beneficial to
Speaker 1: talk about the various orbits that satellites can inhabit and
Speaker 1: then explain the differences between those orbits and the purposes
Speaker 1: of them. And I think that's really helpful in order
Speaker 1: to understand stuff like why is the James Webb Space
Speaker 1: Telescope in an orbit that's so far out that we
Speaker 1: cannot reach it with a human crew? Right? Why is that?
Speaker 1: Or why scientists warn us about the dangers of space chunk.
Speaker 1: I mean, space is huge, so you would think the
Speaker 1: odds of any two objects colliding with one another out
Speaker 1: in space would be astronomical. Man, I'm gonna have a
Speaker 1: lot of puns in this episode. So we're gonna go
Speaker 1: through the various orbits and explain we would send certain
Speaker 1: types of satellites to one orbit versus another. And first
Speaker 1: of all, let's let's actually just talk about the word orbit.
Speaker 1: And I'm sure everyone out there has a grasp on this,
Speaker 1: but technically, what we're talking about is a curved path
Speaker 1: that causes one object to move around a second object,
Speaker 1: or two objects to move around each other due to
Speaker 1: the poll of gravity. And gravity is one of the
Speaker 1: fundamental forces of the universe. It's also the weakest one,
Speaker 1: by the way, it has practically no effect once you
Speaker 1: get down to the molecular or atomic level. Gravity is
Speaker 1: a force of attraction that exists between stuff in our universe.
Speaker 1: What has mass, right, anything that has mass experiences the
Speaker 1: effects of gravity. So technically you could say there's a
Speaker 1: gravitational attraction between every object that has mass and every
Speaker 1: other object that has mass. However, the magnitude of that
Speaker 1: attractive force is dependent upon two really important factors. One
Speaker 1: is the actual mass of the objects in question. The
Speaker 1: more mass, the greater the attraction, So to truly massive
Speaker 1: objects will have a greater attraction to one another than
Speaker 1: two very small objects. This is why when we get
Speaker 1: down to the molecular and atomic levels, gravity is is negligible.
Speaker 1: We can just ignore it. Uh. This, by the way,
Speaker 1: is also why the gravity on the Moon is so
Speaker 1: much less than the gravity on Earth. The acceleration due
Speaker 1: to gravity on the Moon is a little less than
Speaker 1: sevent of that what we'd experienced here on Earth, So
Speaker 1: the gravitational pull between say the Moon and an astronaut
Speaker 1: is much less than what that astronaut would experience while
Speaker 1: walking around on Earth. Because the Moon is less massive
Speaker 1: than the Earth, the astronaut is probably about the same.
Speaker 1: But the other factor is the distance that's between those
Speaker 1: two objects if they are really far apart, the gravitational
Speaker 1: force between them, while technically still being present, will be
Speaker 1: extremely weak. Again, if it's really really far apart, you
Speaker 1: can ignore it because it's so weak as to be
Speaker 1: you know, almost nothing. I should also add the Einstein's
Speaker 1: theory of general relativity actually dismissed the idea of gravity
Speaker 1: being an actual force. Rather, gravity is the consequence of
Speaker 1: objects with mass bending spacetime, and that gets a little
Speaker 1: difficult to envision, so let's simplify it. Imagine that you
Speaker 1: have a trampoline and then you put a pretty heavy
Speaker 1: bowling ball in the middle of that trampoline. Well, the
Speaker 1: weight of the bowling ball will cause the trampoline's surface
Speaker 1: to deform right, it will dip downward because the weight
Speaker 1: of the bowling ball. And if you were to try
Speaker 1: and roll a marble across the trampoline, then it's stead
Speaker 1: of traveling in a straight line, the marble's path would
Speaker 1: be affected by that bend in the trampoline. It would
Speaker 1: actually turn towards the dip and thus towards the bowling ball. Well,
Speaker 1: Einstein's theory stated that we're seeing that exact same effect
Speaker 1: out in the universe, except while we could describe the
Speaker 1: surface of a trampoline effectively as a two dimensional object,
Speaker 1: you know, an object that doesn't have depth to it.
Speaker 1: In space, we have to deal with three dimensions, that
Speaker 1: being spatial dimensions. I mean we also have time, which
Speaker 1: is the fourth dimension. And this gets are a bit
Speaker 1: tricky for us to visualize, or at least I find
Speaker 1: it tricky. Maybe you can do it. I can't. But yeah,
Speaker 1: when we often refer to gravity as a force, Einstein
Speaker 1: would correct us on that one and say it's not
Speaker 1: really a force. Now, with that bowling ball and marble
Speaker 1: trampoline example, we can actually understand why satellites have to
Speaker 1: work in the way that they do. So let's say
Speaker 1: you roll the marble hard enough to reach the point
Speaker 1: where the bowling ball's presence is going to cause the
Speaker 1: marble's pathway to change, But you're not rolling it so
Speaker 1: hard that the marble can make it out the other
Speaker 1: side to the opposite, you know, into the trampoline. So,
Speaker 1: in other words, the marble is unable to escape the
Speaker 1: bowling balls gravitational pull. The marble will roll down and
Speaker 1: hit the bowling ball and come to a stop it
Speaker 1: at some point. Now, if you rolled the marble really hard.
Speaker 1: It might be able to get through the deformed area
Speaker 1: of the trampoline's surface like it might have enough momentum
Speaker 1: too to navigate through the dip. But its path is
Speaker 1: still going to change, right. It's not a flat surface.
Speaker 1: It's not going to travel in a straight line. It
Speaker 1: will have a bend in its pathway. But maybe it
Speaker 1: will get all the way across the trampoline. Uh, it
Speaker 1: just won't be directly across. However, if you wanted to
Speaker 1: keep the marble so that it's constantly circling the bowling ball, well,
Speaker 1: we would have to have some way to keep the
Speaker 1: marble at just the right speed. It would need to
Speaker 1: be fast enough to counteract the marble's tendency to fall
Speaker 1: toward the bowling ball, but not be so fast as
Speaker 1: to cause the marble to continue off the pathway and
Speaker 1: eventually off the edge of the trampoline. If we could
Speaker 1: add energy to the marble consistently, we would be all set,
Speaker 1: because otherwise, the friction that the marble would encounter as
Speaker 1: it rolled across the trampoline would be enough to slow
Speaker 1: it down and it would fall towards the bowling ball.
Speaker 1: So we'd have to find a way to give the
Speaker 1: marble a little boost now and then in order for
Speaker 1: it to maintain its circular pathway around the bowling ball.
Speaker 1: So satellites in orbit around something else, whether it's our
Speaker 1: planet or some other celestial body, need to move at
Speaker 1: a speed that's fast enough to avoid falling toward whatever
Speaker 1: it is orbiting around. So out in space there aren't
Speaker 1: nearly as many factors that would slow down a satellite
Speaker 1: speed as we find here on Earth. There's very little
Speaker 1: friction or air resistance out there, So once you get
Speaker 1: a satellite in orbit, the speed the satellite has courtesy
Speaker 1: of the launch vehicle is sufficient to keep most satellites
Speaker 1: in an orbit for many years. Satellites have thrusters, and
Speaker 1: they have fuel, but those thrusters are not meant to
Speaker 1: accelerate the satellite in order for it to maintain orbital speed.
Speaker 1: Those thrusters are really used to maneuver the satellite so
Speaker 1: it can either transition from one orbit to another, go
Speaker 1: through a transfer orbit in other words, or used to
Speaker 1: move the satellite out of the pathway of potential space
Speaker 1: junk or other debris. Now, satellites and lower orbits can
Speaker 1: and do experience drag from the Earth's atmosphere, so there's
Speaker 1: actually no hard boundary for where our planet's atmosphere ends.
Speaker 1: We do have the Carmen line, which is sort of
Speaker 1: a convenient definite mission of the edge of space, but
Speaker 1: it's mainly there as a way to define it for
Speaker 1: political purposes and just to have a practical definition, because
Speaker 1: it's so nebulous again to use another pun and so
Speaker 1: vague that it's very difficult to say this is uh
Speaker 1: categorically where space begins, and the common line is at
Speaker 1: a hundred kilometers above sea level here on Earth. Now,
Speaker 1: that does not mean that there is no atmosphere beyond
Speaker 1: one kilometers in altitude. There is atmosphere beyond that limit,
Speaker 1: but it's extremely thin. Individual particles can be very far
Speaker 1: apart from each other, so it doesn't resemble the atmosphere
Speaker 1: we have here on the surface. UH. And these few
Speaker 1: particles are still enough to cause drag on lower altitude satellites,
Speaker 1: so gradually those satellite speeds will slow down enough that, um,
Speaker 1: you know, it will eventually de orbit. It will lose
Speaker 1: enough velocity and fall back to Earth unless we were
Speaker 1: to do something like if we were to move it
Speaker 1: to a different orbit than that could be enough to
Speaker 1: extend the life of the satellite, or we might even
Speaker 1: use thrusters to push the satellite out into an orbit
Speaker 1: where it'll just be dead out there in space. Now
Speaker 1: we can classify Earth satellite orbits in different ways, including
Speaker 1: their altitude. Now, we can classify Earth satellite orbits in
Speaker 1: several different ways, and I'll explain some of those ways
Speaker 1: when we come back from this break. Okay, before the break,
Speaker 1: I mentioned we can classify Earth orbits in several different ways.
Speaker 1: One of those ways is the altitude of those orbits.
Speaker 1: Generally speaking, we can split altitudes into low Earth orbit,
Speaker 1: mid Earth orbit, and high Earth orbit. The low orbit
Speaker 1: range is around one to two thousand kilometers above sea level,
Speaker 1: so these are well above the Carmen line. Obviously, remember
Speaker 1: the carbon lines at a hundred kilometers above sea level.
Speaker 1: These satellites move really wicked fast. Uh. These are satellites
Speaker 1: that orbit the Earth several times each day, so they're
Speaker 1: not orbiting the Earth in time with the Earth's rotation.
Speaker 1: They're actually going faster than the Earth's rotation. The lowest
Speaker 1: orbiting satellites are completing in orbit somewhere around minutes per orbit.
Speaker 1: That means a satellite like that could orbit the Earth
Speaker 1: around sixteen times each day. However, lower satellites are going
Speaker 1: to encounter more drag because they're gonna be hitting the
Speaker 1: occasional particle of atmosphere and their orbits will deteriorate faster
Speaker 1: than those satellites that are at a higher orbit. And
Speaker 1: these lower satellites and only be useful for a few years.
Speaker 1: So you wouldn't want anything designed for a long term
Speaker 1: mission to be in that orbit. Uh, it would it
Speaker 1: would not be able to maintain that orbit for longer
Speaker 1: than a few years. In the low Earth orbit range,
Speaker 1: we have a lot of satellites that do Earth observations,
Speaker 1: so satellites meant for Earth sciences often occupy this space.
Speaker 1: In addition, satellites like space x is Starlink network, they
Speaker 1: occupy the low Earth orbit range. There around five kilometers
Speaker 1: above sea level, so not quite in the middle of
Speaker 1: low Earth orbit range. They're actually on the lower end.
Speaker 1: And part of SpaceX's strategy for Starlink is to launch
Speaker 1: tens of thousands of satellites into that general orbit to
Speaker 1: provide global consistent coverage for Internet service and to essentially
Speaker 1: resupply those satellites as older ones are decommissioned, which is
Speaker 1: kind of a fancy way of saying, they either get
Speaker 1: e orbited as then they fall back to Earth or
Speaker 1: they're pushed into an orbit that no one is using,
Speaker 1: kind of a graveyard orbit. Now, the mid Earth orbit
Speaker 1: that ranges from two thousand kilometers above sea level up
Speaker 1: to thirty five thousand, seven hundred eighty kilometers, so a
Speaker 1: big big range here, and a lot of navigational satellites
Speaker 1: and spy satellites occupy this space. Um As out here,
Speaker 1: you can put satellites in an orbit where they stay
Speaker 1: above particular regions for a good amount of time each day.
Speaker 1: And in fact, now we need to talk about a
Speaker 1: special subset of orbits that are kind of between Mid
Speaker 1: Earth and High Earth orbits. And you probably heard terms
Speaker 1: like geosynchronous and geo stationary orbits. These orbits are just
Speaker 1: a touch further out from the mid orbits, and sometimes
Speaker 1: they even get grouped with High Earth orbits. It really
Speaker 1: just depends on whom you're talking to, UH, and it's
Speaker 1: very easy to confuse geosynchronous with geostationary. Technically, geostationary orbits
Speaker 1: are a subset of geosynchronous orbits. So at this altitude,
Speaker 1: this far out from the Earth, the satellites orbit is
Speaker 1: the same as the rotational speed of the Earth. So,
Speaker 1: in other words, the satellite maintains its relative position to
Speaker 1: the Earth throughout the full day. The satellite remains over
Speaker 1: the same general region of the Earth throughout the entirety
Speaker 1: of the day. Now we have to remember that the
Speaker 1: Earth also has a tilt to its axis, and this
Speaker 1: means that if a satellite is at this altitude but
Speaker 1: not directly over the equator, the satellite's position with reference
Speaker 1: to the Earth's surface will actually move north and south
Speaker 1: throughout the day. So it will still maintain its position
Speaker 1: with regard to longitude, that is, east and west. It's
Speaker 1: gonna remain in its same location east versus west, but
Speaker 1: it's latitudinal position north versus south that'll vary throughout the day.
Speaker 1: A geo stationary orbit is an orbit above the equator.
Speaker 1: That means there's a zero degree inclination with reference to
Speaker 1: the equator, and the satellite will remain over the same
Speaker 1: spot on the Earth's surface. But again, this only works
Speaker 1: if you are along the equator. This can get pretty
Speaker 1: congested like there's a There are a lot of reasons
Speaker 1: why you might want to put a satellite there so
Speaker 1: that it's over the same reference point on Earth throughout
Speaker 1: the day. But obviously there's a limited number of of
Speaker 1: orbits that you can put satellites in above the equator
Speaker 1: for one thing, you know, just to avoid things like
Speaker 1: communication interference, so it gets pretty tricky. Also, you you
Speaker 1: often will find countries that do have space programs getting
Speaker 1: treaties and agreement with countries that don't but are equatorial
Speaker 1: countries so that they can essentially get the rights to
Speaker 1: place a satellite above those countries. This is one of
Speaker 1: those cases where it's not just science and technology but
Speaker 1: politics that become important. And then you also have high
Speaker 1: Earth orbit was where we start to go beyond the
Speaker 1: geo stationary and geosynchronous orbits. We're talking about altitudes greater
Speaker 1: than thirty five thousand seven kilometers now way out here,
Speaker 1: you typically are talking about things like communications, satellites, um
Speaker 1: it can be other things too, but you know, you
Speaker 1: start to get limited in what useful stuff you can
Speaker 1: put out in this orbit. Oddly enough, when you go
Speaker 1: much further out you can find uh other really interesting
Speaker 1: uses like the James Webb Space Telescope. But we'll get
Speaker 1: there now. I mentioned geo stationary orbits, which requires the
Speaker 1: satellite to not only be above the mid Earth orbital age,
Speaker 1: but also over the equator ak zero inclination with reference
Speaker 1: to the equatorial plane. But we can classify other orbits
Speaker 1: by referencing inclination. For example, a polar orbit is one
Speaker 1: that passes over the North and South Pole over the
Speaker 1: course of its orbit, and this requires an inclination of
Speaker 1: ninety degrees. That is, it needs to be at a
Speaker 1: right angle with reference to the equator. And then you
Speaker 1: have sun synchronous orbits. Okay, so this gets really complicated,
Speaker 1: but I'll try and give you a very very high
Speaker 1: level view. Again. Another pun and you might want a
Speaker 1: satellite in a sun synchronous orbit to observe certain regions
Speaker 1: of the Earth, and you want the lighting of those
Speaker 1: regions to be consistent from one day to the next. Well,
Speaker 1: if you want to do that, you put a satellite
Speaker 1: in a polar sun synchronous orbit. This is an glinnation
Speaker 1: of about ninety eight degrees, so it's a little bit
Speaker 1: further out from a right angle, and a satellite in
Speaker 1: this orbit will orbit north south or depending upon your
Speaker 1: point of reference, south north around the Earth, and meanwhile
Speaker 1: the Earth is continuing to rotate east west below the satellite. Now, interestingly,
Speaker 1: the satellite's orbital path will also begin to rotate. In fact,
Speaker 1: that's actually crucial because if the orbital path did not rotate,
Speaker 1: you know, you can think of it like a hula
Speaker 1: hoop around a globe, where the hula hoop is going
Speaker 1: over the north and south pole, so it's vertical with
Speaker 1: respect to the globe. Then imagine that you would slowly
Speaker 1: twist the hula hoops so that it is actually orbiting
Speaker 1: the Earth that way as well. It's important because you
Speaker 1: have to remember the Earth is an orbit around the Sun.
Speaker 1: So in order for you to have a consistent satellite
Speaker 1: view with the same lighting over the same region each day,
Speaker 1: the orbit has to rotate, right, because the Earth is
Speaker 1: going around a circular path of the Sun. If the
Speaker 1: orbit didn't rotate, then you wouldn't have that effect of
Speaker 1: passing over the same region um at the same time
Speaker 1: of day each day. Now, the rotation of the orbit
Speaker 1: happens because the Earth is not a perfect sphere. It's
Speaker 1: a bit bigger around the equator and holy cats, I
Speaker 1: can totally relate to that. And so the equator region
Speaker 1: exerts the gravitational pull on the satellite that if no
Speaker 1: other physics were involved, would ultimately cause the satellite's orbit
Speaker 1: to drift into one that's over the equator. But due
Speaker 1: to the satellite's angular momentum, the satellites orbit doesn't tilt
Speaker 1: down to become equatorial. Instead, the whole orbit rotates. If
Speaker 1: you if you were to ever use a coin, and
Speaker 1: you've seen a coin start to do that that cool
Speaker 1: rotate thing on a table, like it's it's starting to fall,
Speaker 1: but it hasn't actually clattered flat on the table, but
Speaker 1: it's doing that thing where it's kind of rotating around,
Speaker 1: almost like a top. That's kind of what the orbit
Speaker 1: is doing. And the rotational speed of the Earth, the
Speaker 1: rotational speed of the orbit, and the period of the
Speaker 1: orbit line up so that the satellite will always pass
Speaker 1: over a specific spot on the Equator at the same
Speaker 1: time of day each day. So let's say it passes
Speaker 1: over Bogatam at three pm. Well that's gonna happen from
Speaker 1: there on out, So tomorrow it'll be overhead of Bogata
Speaker 1: at three pm, and the next day, and the next
Speaker 1: day and so on. Subsequent orbits throughout the day will
Speaker 1: have the satellite pass over different equatorial cities, like say
Speaker 1: Singapore or Nairobi, and it will always pass over those
Speaker 1: respective cities at the same time of day each day
Speaker 1: for that city. I'm not saying it will pass over Bogata,
Speaker 1: Singapore and Nairobi at three pm. That would be impossible,
Speaker 1: but that they will pass over uh those respective cities
Speaker 1: at the same time per day. And I realized that
Speaker 1: this gets really tricky to imagine. It's hard to explain
Speaker 1: without visual aids. So if you're having trouble getting a
Speaker 1: handle on polar Sun synchronous orbits, I recommend searching for
Speaker 1: videos that illustrate how they work. Also, I'm not even
Speaker 1: scratching the surface here as far as how complicated these get.
Speaker 1: If you really want to learn more, I recommend a
Speaker 1: paper by Ronald J. Bowaine, and it's titled A B
Speaker 1: C's of Sun Synchronous Orbit Mission Design. It is a
Speaker 1: really good paper that goes into the technical details. Anyway,
Speaker 1: you might wonder why we would even worry about getting
Speaker 1: that kind of information in the first place, Like what's
Speaker 1: the big deal. Why do we even care about getting
Speaker 1: a satellite out there to pass over the same part
Speaker 1: of the Earth at the same time of day each day. Well,
Speaker 1: one reason is that it helps us track changes in
Speaker 1: a region over time. This is particularly important as we
Speaker 1: examine the effects of climate change in that region. So
Speaker 1: you want as many factors to be the same in
Speaker 1: your observation so that any differences you see you can say, well,
Speaker 1: this clearly didn't show up because the satellite is passing
Speaker 1: over at a different time of day, so the lightings
Speaker 1: at a different angle instead, Uh, really reflective of actual
Speaker 1: changes that are happening on the ground. So keeping as
Speaker 1: much of your other factors consistent as possible is really important.
Speaker 1: Keeping in mind that obviously, like angles of light are
Speaker 1: going to change as the seasons change, but you know
Speaker 1: that's something you can you can factor in. Whereas like
Speaker 1: you want to be able to say, like, from one
Speaker 1: summer to the next, Oh, we've seen that, say the
Speaker 1: coastline of this region has changed dramatically, and potentially that's
Speaker 1: due to climate change. That's why you would need to
Speaker 1: have something like this so that you could draw those
Speaker 1: kind of conclusions. All Right, we've got more to say
Speaker 1: about orbits. I know it's just gonna keep on going
Speaker 1: around and around, because that's what orbits do. But before
Speaker 1: we get to that, let's take another quick break. Okay,
Speaker 1: so far, what I've described are you could essentially call
Speaker 1: them circular orbits. They don't have to be, but that's
Speaker 1: the way we typically imagine orbits, or at least the
Speaker 1: way I typically imagine an orbit is kind of like
Speaker 1: a circle around whatever body it's orbiting, so they more
Speaker 1: or less keep a a consistent distance from the the
Speaker 1: orbiting uh center, so Earth. In other words, like they
Speaker 1: would just keep a pretty consistent distance from the Earth.
Speaker 1: But orbits do not have to be perfectly circular, or
Speaker 1: even circular at all. You can have elliptical orbits, and
Speaker 1: an elliptical orbit is oval in shape, and this means
Speaker 1: that the satellite's distance from the Earth varies throughout its
Speaker 1: orbital path. That also means that the satellite's velocity will
Speaker 1: change as it orbits the Earth. So as the satellite
Speaker 1: is moving toward the Earth, its velocity will start to
Speaker 1: increase due to the Earth's gravitational pull, and as it
Speaker 1: moves away from the Earth, its velocity begins to slow
Speaker 1: down again because the Earth's gravity is pulling back on it.
Speaker 1: Now the low point of the orbit, so the part
Speaker 1: where the satellite is closest to the Earth is called
Speaker 1: the parage, the furthest point from the Earth is the apogee.
Speaker 1: That's the high point of the orbit. And a lot
Speaker 1: of communication satellites have an elliptical orbit. And you might
Speaker 1: wonder why, Well, because an elliptical orbit means that a
Speaker 1: satellite is going to travel over a specific region for
Speaker 1: a really long time as it moves through its apogee, right,
Speaker 1: because it's slow, and this is the part where it's
Speaker 1: for this from the Earth, So you can provide a
Speaker 1: long period of coverage UH using this kind of orbit.
Speaker 1: And then when it moves out of sight, when it's
Speaker 1: out of the line of sight, it's actually starting to
Speaker 1: approach its parage, so it speeds up, so it zips
Speaker 1: around the back of the Earth. So this way you
Speaker 1: have UH limited interruptions of coverage. And if you have
Speaker 1: just a few set communication satellites that have these kind
Speaker 1: of elliptical orbits over a region, you can have consistent
Speaker 1: communications coverage over that region and you don't have to
Speaker 1: use as many satellites. UH. You just have to have
Speaker 1: enough so that there's one to cover. When you know,
Speaker 1: when satellite A is moving out of site, you have
Speaker 1: a satellite B that you can switch to that will
Speaker 1: continue coverage. So these are really important orbits specifically for
Speaker 1: communications uh satellites, not just them, but that's a big
Speaker 1: reason to to use an elliptical orbit. And sometimes we
Speaker 1: describe these satellites with these orbits as having highly elliptical
Speaker 1: orbits or h e O s. And then let's wrap
Speaker 1: this up with lagrange orbits or lagrange points. Okay, so
Speaker 1: there are a few positions in space in our Solar
Speaker 1: System where if you place an object there, it tends
Speaker 1: to stay there relatively speaking. I mean, you do have
Speaker 1: to remember that all of us, our Solar System included,
Speaker 1: we're all whizzing through space. So really when we say
Speaker 1: it stays there, we we mean relative to Earth or
Speaker 1: in it doesn't have to be Earth. You can have
Speaker 1: lagrange points around any orbiting objects, but we primarily concern
Speaker 1: ourselves with the Earth lagrange points. So at these points
Speaker 1: in space, the gravitational pull of two large masses on
Speaker 1: an object precisely matched this in tripetal force needed for
Speaker 1: that object to move with them, so that that's complicated,
Speaker 1: but it's kind of like saying, imagine you've got a
Speaker 1: tug of war game and both sides of the game
Speaker 1: are of perfectly equal strength. So the middle of the
Speaker 1: rope that's being used in the tug of war isn't
Speaker 1: going anywhere because the forces that are acting on it
Speaker 1: on either side are equal. Well, there are five lagrange
Speaker 1: points in our Earth and Sun relationship Earth Sun Moon.
Speaker 1: Really one is on the opposite side of the Earth
Speaker 1: from the Sun, so it's always on the night side
Speaker 1: because it's always going to be on the opposite side
Speaker 1: of the Earth from where the Sun is. This is
Speaker 1: at a point that's actually beyond our moon, so it's
Speaker 1: it's beyond lunar orbit. This is the L two lagrange point.
Speaker 1: This is where the James Web Space Telescope is, along
Speaker 1: with a few other space observation satellites, and it's useful
Speaker 1: because when you put satellites out in this point, they
Speaker 1: are protected from the radiation of the Sun. So if
Speaker 1: you're trying to detect very faint sources of radiation out
Speaker 1: in the in the in the universe, then you don't
Speaker 1: have to worry about the radiation from the Sun interfering um.
Speaker 1: You also only need a heat shield on one side
Speaker 1: of the satellite because it's going to be the heat
Speaker 1: that's radiated from the Sun and the Earth which will
Speaker 1: be behind that satellite. Well it's facing out towards you know, space.
Speaker 1: The L one lagrange point is between the Earth and
Speaker 1: the Sun. It's actually much closer to the Earth than
Speaker 1: the Sun. But that makes sense because remember gravitational force
Speaker 1: sorry Einstein, is dependent upon not just mass but distance.
Speaker 1: So you have, since the Earth is far less massive
Speaker 1: than the Sun, you have to have the satellite at
Speaker 1: a position that's much closer to the Earth than it
Speaker 1: is to the Sun. But once you get to that
Speaker 1: sweet spot, it'll pretty much stay there. And we've got
Speaker 1: satellites in that orbit that are designed to observe the Sun.
Speaker 1: So that's how we, you know, get something that is
Speaker 1: in a fixed orbit between the Earth and the Sun.
Speaker 1: It can maintain that orbit and it can have continuous
Speaker 1: observation of the Sun, which is really useful science information
Speaker 1: for us. There's the L four and L five lagrange points.
Speaker 1: These are actually along the Earth's orbit around the Sun.
Speaker 1: So there's one leading the Earth's orbit and one trailing
Speaker 1: behind the Earth's orbit, and they're each at a sixty
Speaker 1: degree angle out from the Earth with respect to the Sun.
Speaker 1: These points are the only ones where an orbit can
Speaker 1: just be stable without further adjustments orbits at the other
Speaker 1: lagrange points are delicate. They require near constant adjustments to
Speaker 1: maintain in place. I saw one uh analogy that suggested
Speaker 1: it's kind of like arching a ball on the point
Speaker 1: of a pyramid, and you have to do it just
Speaker 1: right for it to maintain balance, and you probably are
Speaker 1: going to have to do constant adjustments so that it
Speaker 1: doesn't tip over. And finally, we have the L three
Speaker 1: lagrange point. This one's on the opposite side of the
Speaker 1: Sun from the Earth, So if you were to draw
Speaker 1: a straight line from the Earth through the Sun to
Speaker 1: the other side, that's where the L three point is.
Speaker 1: We are not likely to ever use that for a
Speaker 1: satellite for a good reason, because the Sun would always
Speaker 1: be between us and that satellite, and the Sun would
Speaker 1: block any communications that we could send to or from
Speaker 1: that satellite. You could presumably have some form of space
Speaker 1: station there, I guess, but it would be one that
Speaker 1: would be effectively cut off from the Earth without you know,
Speaker 1: some other network out there, because again the Sun is huge,
Speaker 1: it's gonna block all other communication efforts. But that is
Speaker 1: a quick rundown of satellite orbits. Obviously, it gets way
Speaker 1: more complex than this, And again I didn't touch things
Speaker 1: like orbits around other planets, which can get pretty complicated,
Speaker 1: particularly with planets that have lots of moons on them. Um.
Speaker 1: And obviously the plants also have different masses, which means
Speaker 1: that you're taking different things into consideration as far as
Speaker 1: the gravitational pull. So yeah, it does get really complicated,
Speaker 1: but I wanted to make sure that we had sort
Speaker 1: of a basic coverage of the subject to kind of
Speaker 1: kind of get an appreciation for all how complicated this is.
Speaker 1: As for space junk, well, I mean, there are certain
Speaker 1: orbits that are very valuable and they can only hold
Speaker 1: a certain amount of satellites before you start to run
Speaker 1: into the possibility of collisions in that orbit, which obviously
Speaker 1: can cause an enormous problem. Not only are you talking
Speaker 1: about the potential destruction of at least two satellites, you're
Speaker 1: also talking about those satellites then creating more space junk,
Speaker 1: like more shrapnel if you will, that can potentially put
Speaker 1: other satellites in danger, and it can become this cascade effect. Uh,
Speaker 1: you know, there are graveyard orbits that we've had, you know,
Speaker 1: satellites get pushed into in order to kind of be
Speaker 1: out of the way. But that will eventually get pretty
Speaker 1: complicated to Also, another big issue for astronomers here on
Speaker 1: Earth is that the more satellites we put out in space,
Speaker 1: the more interference there is for astronomical observations, at least
Speaker 1: using earth bound telescopes. So that's another big issue UM,
Speaker 1: and it's complicated, Like you start looking at things like
Speaker 1: SpaceX's plan with Starlink, and it's not the only Internet
Speaker 1: based satellite system that's been proposed to use you know,
Speaker 1: thousands and thousands of satellites. There are others as well,
Speaker 1: and you start to see where the potential issues are.
Speaker 1: And we've had people warning about the dangers of space
Speaker 1: junk for a very long time, but I feel like
Speaker 1: there hasn't really been a huge move on the regulations
Speaker 1: side to kind of curb that UM. And of course
Speaker 1: certain countries are probably a bit more gung ho about
Speaker 1: pursuing opportunities to get satellites on in orbit than others.
Speaker 1: So this is going to continue to be an issue
Speaker 1: and it's just going to get worse before it gets better. Uh,
Speaker 1: it is odd to think that for something as vast
Speaker 1: as space, there is this ligitimate concern about the potential
Speaker 1: for collisions in these specific orbits. But that's where we are. Okay,
Speaker 1: that's it for our brief overview of satellite orbits. Hope
Speaker 1: you learn something, Hope you enjoyed this. Hope you go
Speaker 1: out and look up more information about this so that, uh,
Speaker 1: you know, my poor explanations can become more clear. As
Speaker 1: you see things like video representations of these orbits, you
Speaker 1: can kind of understand why we use the orbits that
Speaker 1: we do. And if you have suggestions for future topics
Speaker 1: I should cover on tech stuff, whether it's a technology,
Speaker 1: a company, a person in tech, a trend, something basic
Speaker 1: that you would like me to explain in the tech
Speaker 1: stuff tidbits, let me know the best way to do
Speaker 1: that is to reach out on Twitter. The handle for
Speaker 1: the show is tech Stuff hs W, and I'll talk
Speaker 1: to you again really soon. Text Stuff is an I
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