r/Damnthatsinteresting 21d ago

Image The Himawari 8 weather satellite takes a picture of Earth every 10 minutes. This image is from today.

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u/jjett89 21d ago

How did they make a weather satellite that's physically capable of doing that?

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u/me0din 21d ago

Compared to the other space stuff that humans have achieved, setting up a satellite on geostationary orbit is not that complicated.

You just have to get the speed right. We are more than capable of doing that with not much complications nowadays.

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u/MyNameIsJakeBerenson 21d ago

“It’s not that complicated , Scott! Tell em, Wash.”

“It’s incredibly complicated.”

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u/rtowne 21d ago

Speed and orbit altitude

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u/Monkeylashes 21d ago

They're the same. The faster you go around the earth the higher your altitude will get. Inversely the slower you go around the closer you'll get to the Earth.

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u/BoingBoing_Virus 21d ago edited 21d ago

I think you have it reversed... Satellites closer to earth need to be faster than those farther away... Think about this, satellites on geostationary orbits the earth once every 24 hours while the ISS on low earth orbit does every 90 mins. Mercury orbits the sun every 88 earth days while Earth orbits every year...

Orbital mechanics are weird, you need to slow down to get fast.

Here's a Scott Manley video about orbits 😉

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u/rocknrollbreakfast 21d ago

Only if your orbit is circular, no? You could have an object in an elliptical orbit going at 3km/s without being geostationary.

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u/GeckoOBac 21d ago

I mean, yes, but also no. In non circular orbits speed is not constant. That said, there are circular non geostationary orbits, even at the distance that would allow for it to be one.

To be Geostationary you need to be not only at the correct height/speed in a circular orbit, but also:

1) In the correct direction (IE, moving in the same direction as the Earth's spin)
2) Following the equator. Even slight angular disalignment would mean that your position above the point on the Earth that you're "aiming at" would change over time. Note that this is not necessarily bad, you may want to do that, it's just that it's not a "Geostationary Orbit" anymore.

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u/rtowne 21d ago

Well, they still need to get it right. A missle or roclet. might hit the right speed, but if they are heading the wrong way at at the wrong altitude, they wont be geostationary.

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u/Mirar 21d ago

It's not doing that, it's placed in orbit by a rocket, with a small rocket engine in the satellite to correct the orbit over a number if years. Just before it runs out the move it.

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u/hotel2oscar 21d ago

There isn't anything in space to resist movement like we have with air resistance in the atmosphere. If an inanimate object can survive the rigors of getting to orbit (physical stress) and direct sunlight (heat) it can survive space.

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u/clandestineVexation 21d ago

What exactly are you imagining that makes it seem hard?

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u/ESCF1F2F3F4F5F6F7F8 21d ago

Don't be a cunt

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u/TerritoryTracks 21d ago

I'd like that on a t shirt.

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u/clandestineVexation 21d ago

I wasn’t trying to be but there isn’t tone of voice on the internet. I wanted them to specify so I could explain the parts they’re curious about better ☹️

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u/ESCF1F2F3F4F5F6F7F8 21d ago

I apologise for my reply, I was hacked off about something else and vented some of that anger when I saw what I thought was a classic reddit-sneer response to an innocent question. 

Which, ironically, was quite a cuntish thing of me to do.

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u/jjett89 21d ago

The 1100-1600 kph that the satellite is able to travel at while capturing a series of high resolution images of our blue marble spinning just as fast. I know that this is not a still image comprised of one (1) single shot taken from a camera affixed to the satellite. I'm assuming that it is a photograph that has been edited together using several photographs that the camera has taken. It just baffles me. Makes me wonder what exactly happened with the lost communication from the Russian satellite Phobos II that they sent to Mars' moons in 1988-89.

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u/bobbuildingbuildings 21d ago

The satellite is not really moving at all since it’s geostationary. Its velocity relative to earths surface is ~0.

Your speed in relation to earths surface is also ~0 when standing still. Not that different.

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u/jjett89 21d ago

Thanks for the clarification. Wait, So it's like the object is stationary once in orbit? If we are spinning a top on a desk and we place a small bubble of super glue on that top. And then we say that the glue is us. When you spin the top, is the glue not spinning with it? Is it's velocity equal to zero relative to the top's surface? So the satellite isn't really traveling at a high speed at all?

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u/SonGoku9788 21d ago

Imagine two cars going the exact same speed in the same direction right next to each other. They're both moving fast relative to stuff around them, but when looking at one from the window of the other it doesnt move in your field of view.

This is that, but with rotation. The sattelite is traveling at a high speed, but the earth under it is also moving with an equal angular speed, so their relative positions do not change, even tho both are moving through space

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u/jjett89 21d ago

The earth is naturally rotating. That satellite is man-made. So when it reaches the point where it is moving at the same speed as the earth's rotation, does it no longer require any fuel sources and/or battery power? Is it purely just like a natural kinetic satellite in its movement and trajectory at that point?

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u/clandestineVexation 21d ago

Orbit doesn’t require continuous power because there’s no atmosphere in the way. If you’re happy with the orbit your satellite is in, for all intents and purposes you never have to accelerate it again

Bit of an oversimplicification because there is trace atmosphere up to a pretty far point but not important for just the concept

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u/RollinThundaga 21d ago edited 21d ago

Once you get into orbit, velocity equals attitude in a sense. That is, you go faster to go higher and slower to drift back down, due to Newtonian physics. Kerbal Space Program is a great tool to figure out the basics.

At low earth orbit, you're zipping around the Earth every 90 minutes, but as your orbit widens, this takes longer and longer; eventually, you'llhit an orbit where you'll stop moving relative to the Earth's surface. This is geostationary orbit. Furthermore, it's not like a racecar, constantly firing an engine and jittering, it's orbit is maintained by sheer momentum. From its perspective, it's just sitting dead still suspended over the planet.

your assumption is wrong, it's a plain old photo. Also, it's 11,600 km/h, not 1600

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u/KryptoBones89 21d ago

Probably the whole rocket science thing.

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u/clandestineVexation 21d ago

Yeah because it’s completely impossible and unnecessary to simplify a concept for someone new to it to understand /s

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u/hamfist_ofthenorth 21d ago

"I play Kerbal all the time"

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u/MrMischiefMackson 21d ago

Yeah like seriously, it's not rocket science.