Many people don't know that you can actually see some of these satellites in the sky as they pass overhead, without a telescope or anything. I made a site to help catch them, which has been on HN before: https://james.darpinian.com/satellites/
This is bit of an off-topic question, and I realize that it might sound a bit "out there", but I'm compelled to ask and I'll take the down-votes that I deserve:
Twice in my life I have seen what I believed to be a satellite make a sudden and abrupt (near instantaneous) 90-degree turn. I realize this is impossible [probably?], which is why I ask. Once was in 1992 - and I spent nearly 30 years telling myself I mis-remembered. And the second time was in 2018 while backpacking with my wife - she was a second witness and confirmed that we saw the same thing. Both times the turn occurred when directly over-head.
When casually stargazing, I don't spot the satellites when they first pop up on the horizon. I usually spot them around 30-45 degrees above the horizon. One way to differentiate between an aircraft and a satellite is the blinking, but that's not always reliable - so a more reliable way is to note how quickly the "perceived" speed changes as it moves from 30-degrees towards the azimuth. The larger the change in perceived speed, the lower the altitude, while constant speed indicates orbit.
In both cases, I was casually looking at the sky - I had no measurement or recording tools. In both cases I took mental note of the speed when I first spotted it and how it changed (or didn't) as it moved. I mentally noted that that both appeared to be a satellite. Obviously, a 90 degree turn is impossible (?), which leads me to guess that I may have seen an extremely high altitude, high speed, aircraft make a near 90 degree turn while reflecting sunlight shortly after sunset. This also seems to be a stretch.
I hate to ask such far-fetched "I saw..." questions here, but it's been driving me nuts since 1992. All attempts at research have been fruitless. I thought maybe someone here could help?
Great site. The easiest/laziest (in a good way! - I need a one or two click interface right now) method of finding the next star-link pass that I know of. Thank you!
I take my two-year-old out satellite hunting a few times a week. He’s a big fan of Pluto but understands we can’t see it like we can some satellites, plus Venus, Saturn, Sirius, etc.
Of course he’d still rather see a truck!
I like this a lot because it shows the distance between me and the satellite on the same scale as the distance between me and other ground locations. Otherwise it's hard to know how close/far satellites are.
Thank you. I've been wanting to spot some Starlink satellites for awhile, but I haven't been able to using sites that tell azimuth & elevation with a date. I like that your site shows the satellites superimposed on google street view so I know exactly where to look. I'm going to try to spot a starlink train tonight.
Cool! Many years back I made a little program that scraped HeavensAbove data and local weather, and made my phone buzz when there was about to be a bright Iridium flare overhead (just the good ones - every week or two).
I remember being able to see them fly over slowly when hunting in northern russia as a kid. Maybe my eyesight is not so good anymore but I doubt it’s doable within few hundred miles of any major population center today.
They're working on four additional radar installations for tracking space debris. Their current installations can track objects down to about a 10 cm diameter, but with their new installations they'll theoretically be able to track objects as small as 2 cm. In general, current radar systems tend to be limited on the lower end to objects in the 5-10 cm range. Systems like LeoLabs’ and the US Air Force’s upcoming Marshall Islands-based Space Fence will improve coverage, but still won’t see the 128 million objects from 1 mm to 1 cm. For perspective, a collision with a 10 cm object will likely completely destroy a satellite, a 1 cm object will likely disable it, and a 1 mm object may disable a subsystem. At closing velocities around 10 km/s, the kinetic energy of even an untrackable chip of paint is greater than the destructive power of an equivalent mass of stationary TNT. Whipple shields around the ISS’s crewed areas are built to absorb impacts with objects of up to around 1 cm. For anything bigger, an avoidance maneuver is used (if we see it coming).
Wow 2cm is still huge if it rams into the ISS at 10km/s. It's like a 20mm bullet with at least 5 times the speed of a gun round (not sure how fast guns are actually :) What are those 'whipple shields'? Are those the foil sheets that basically vaporise the object (and part of the shield) so it won't penetrate the inner hull?
I assume they have better tracking than 2cm for the orbit the ISS is in? Does the ISS have its own radar warning? Though I guess if it sees it coming it's already too late for avoidance.
This is so amazingly cool. Wow. You can even see 3D models (probably from a list of standard ones) and how they tumble (I wonder how accurate that is?)
Thanks vortex_ape. I love the way random cool stuff pops up on HN like this.
PS: It does look a lot more crowded in space in this view than it actually is, because the objects are shown at like a million times their actual size :) And it doesn't show vertical separation graphically.
I wonder is there a way to "make it scale" in the sense where the planet stays the same size but the satellites become like a pixel... so you can more accurately see how far apart things are... seems like "omg Kessler syndrome" whenever I see these things.
I don't follow the space industry as closely as I used to so I don't know how true this is, but some folks have accused Leolabs of being a bit alarmist with their conjunction alerts. They have sent out alerts for collisions that the DoD said had essentially 0 chance of happening (and they didn't).
If you were cynical, you might say that those sorts of false alarms are a marketing/PR stunt. If that's the case, it's in their best interest to not offer to-scale visualizations, making LEO look as crowded as possible.
I've been meaning to implement SGP4 from scratch as a learning exercise. What I found really interesting is how the USAF/NORAD tracks and reports objects in LEO: they publish Two-line Element Sets (TLEs), which are a fixed-width ASCII format derived from punch cards.[1] The format is pretty easy to parse.[2]
Just want to give props to the skyfield python library. I have no idea what any of the numbers in the TLE mean but just by following some examples have been able to plot the location of Starlink satellites vs time very easily.
Pretty incredible. I would like to see the assets to scale though, otherwise it seems crowded up there when it clearly isn't. It reminds me of all those graphics a year ago of the Australian bushfires where the fires were represented by huge graphics that were completely out of scale to the actual fire and folk actually believed that Australia was just charcoal!
This just made me realize, if cars are to satellites, we don't really have a bus to xyz equivalent. Cars are great and all, it gave a generation flexibility to go where they like but they don't scale. There are denser forms of transport for urban areas like rail or bus. And as the sky gets more debris filled it's going to be like the urban area analogy where we need a public transport for space where we co-locate payloads on one object at scale. Some places host a 3rd party payload on one satellite, but nobody hosts 50 on one structure.
One of the harder parts about that is setting up the attitude of the SV so that each payload gets time pointed at the earth (if that's what it cares about). A while back I worked on https://en.wikipedia.org/wiki/CASSIOPE, which had multiple payloads, and giving each of them appropriate earth-facing time at specific parts of the orbit was... a delicate scheduling problem.
Filter for starlink in the top left and set the speed at 200 or so.
Very interesting and entertaining. I’ve not been excited for a piece of tech in years but starlink has me on the edge of my seat. I can’t wait to get my equipment.
Feel that initially when you load this page, it looks crowded. Which for visualization sake makes sense, but it definitely doesn’t do space justice. It’s just so vast, and there’s so much more space that all these satellites would practically be invisible.
The way they're laid out on the map looks like there should be thousands of collisions every second. True size of each object is not perceptible on this and the distance between each object. Is there a log of collisions in real time?
I'd also like to know if there are non-artificial objects orbiting earth what their ratio is compared to man-made objects. Are there an equal amount or perhaps more comet/astroid-type objects that we simply don't track?
Is it fair game if a space company developed a craft that gathered and collected the non-working objects or somehow brought them back to earth and mined their precious metals or otherwise take their technology etc?
Works well on my wee i5 laptop, and certainly a LOT better than ye olde NASA World Wind with all the satellite plugins added on, which regularly crashed my machine when I used to play with it back in 2005 or so!
[+] [-] modeless|5 years ago|reply
[+] [-] daveslash|5 years ago|reply
Twice in my life I have seen what I believed to be a satellite make a sudden and abrupt (near instantaneous) 90-degree turn. I realize this is impossible [probably?], which is why I ask. Once was in 1992 - and I spent nearly 30 years telling myself I mis-remembered. And the second time was in 2018 while backpacking with my wife - she was a second witness and confirmed that we saw the same thing. Both times the turn occurred when directly over-head.
When casually stargazing, I don't spot the satellites when they first pop up on the horizon. I usually spot them around 30-45 degrees above the horizon. One way to differentiate between an aircraft and a satellite is the blinking, but that's not always reliable - so a more reliable way is to note how quickly the "perceived" speed changes as it moves from 30-degrees towards the azimuth. The larger the change in perceived speed, the lower the altitude, while constant speed indicates orbit.
In both cases, I was casually looking at the sky - I had no measurement or recording tools. In both cases I took mental note of the speed when I first spotted it and how it changed (or didn't) as it moved. I mentally noted that that both appeared to be a satellite. Obviously, a 90 degree turn is impossible (?), which leads me to guess that I may have seen an extremely high altitude, high speed, aircraft make a near 90 degree turn while reflecting sunlight shortly after sunset. This also seems to be a stretch.
I hate to ask such far-fetched "I saw..." questions here, but it's been driving me nuts since 1992. All attempts at research have been fruitless. I thought maybe someone here could help?
[+] [-] tobmlt|5 years ago|reply
I take my two-year-old out satellite hunting a few times a week. He’s a big fan of Pluto but understands we can’t see it like we can some satellites, plus Venus, Saturn, Sirius, etc. Of course he’d still rather see a truck!
[+] [-] walrus01|5 years ago|reply
[+] [-] neolog|5 years ago|reply
[+] [-] nbar|5 years ago|reply
[+] [-] bloopernova|5 years ago|reply
[+] [-] poopsmithe|5 years ago|reply
[+] [-] rkagerer|5 years ago|reply
[+] [-] dilyevsky|5 years ago|reply
[+] [-] greypowerOz|5 years ago|reply
ps i didn't see a way to manually set a location, maybe just my old android tablet...
[+] [-] dmitryminkovsky|5 years ago|reply
[+] [-] tectonic|5 years ago|reply
They're working on four additional radar installations for tracking space debris. Their current installations can track objects down to about a 10 cm diameter, but with their new installations they'll theoretically be able to track objects as small as 2 cm. In general, current radar systems tend to be limited on the lower end to objects in the 5-10 cm range. Systems like LeoLabs’ and the US Air Force’s upcoming Marshall Islands-based Space Fence will improve coverage, but still won’t see the 128 million objects from 1 mm to 1 cm. For perspective, a collision with a 10 cm object will likely completely destroy a satellite, a 1 cm object will likely disable it, and a 1 mm object may disable a subsystem. At closing velocities around 10 km/s, the kinetic energy of even an untrackable chip of paint is greater than the destructive power of an equivalent mass of stationary TNT. Whipple shields around the ISS’s crewed areas are built to absorb impacts with objects of up to around 1 cm. For anything bigger, an avoidance maneuver is used (if we see it coming).
[+] [-] tectonic|5 years ago|reply
(Some of the paragraph I posted was excerpted from a recent issue.)
[+] [-] GekkePrutser|5 years ago|reply
I assume they have better tracking than 2cm for the orbit the ISS is in? Does the ISS have its own radar warning? Though I guess if it sees it coming it's already too late for avoidance.
[+] [-] objectivetruth|5 years ago|reply
[+] [-] GekkePrutser|5 years ago|reply
Thanks vortex_ape. I love the way random cool stuff pops up on HN like this.
PS: It does look a lot more crowded in space in this view than it actually is, because the objects are shown at like a million times their actual size :) And it doesn't show vertical separation graphically.
[+] [-] jcun4128|5 years ago|reply
Man this thing is nuts the zoom is neat
[+] [-] Rebelgecko|5 years ago|reply
If you were cynical, you might say that those sorts of false alarms are a marketing/PR stunt. If that's the case, it's in their best interest to not offer to-scale visualizations, making LEO look as crowded as possible.
[+] [-] devbug|5 years ago|reply
I've been meaning to implement SGP4 from scratch as a learning exercise. What I found really interesting is how the USAF/NORAD tracks and reports objects in LEO: they publish Two-line Element Sets (TLEs), which are a fixed-width ASCII format derived from punch cards.[1] The format is pretty easy to parse.[2]
[1]: https://en.wikipedia.org/wiki/Two-line_element_set [2]: https://www.celestrak.com/NORAD/documentation/tle-fmt.php [3]: https://www.celestrak.com/NORAD/documentation/checksum.php
[+] [-] jcims|5 years ago|reply
https://rhodesmill.org/skyfield/
I’m feeding it into Graphana to help visualize how satellite coverage impacts the signal strength and network performance of my dish. It’s pretty fun.
[+] [-] altitudinous|5 years ago|reply
[+] [-] Fordec|5 years ago|reply
[+] [-] tonyarkles|5 years ago|reply
[+] [-] King-Aaron|5 years ago|reply
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[+] [-] leolabs_eng|5 years ago|reply
[+] [-] unknown|5 years ago|reply
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[+] [-] leetrout|5 years ago|reply
Very interesting and entertaining. I’ve not been excited for a piece of tech in years but starlink has me on the edge of my seat. I can’t wait to get my equipment.
[+] [-] mrep|5 years ago|reply
[+] [-] zuhayeer|5 years ago|reply
[+] [-] unknown|5 years ago|reply
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[+] [-] soheil|5 years ago|reply
[+] [-] modeless|5 years ago|reply
[+] [-] soheil|5 years ago|reply
[+] [-] soheil|5 years ago|reply
[+] [-] oraphalous|5 years ago|reply
[+] [-] AlphaGeekZulu|5 years ago|reply
[+] [-] winrid|5 years ago|reply
By the way, look for the starlink sats. Very cool. Wonder how many conjunctions they've had :)
[+] [-] Karawebnetwork|5 years ago|reply
[+] [-] danielyaa5|5 years ago|reply
[+] [-] leolabs_eng|5 years ago|reply
Should work on phones, tablets, and others.
What're your specs?
[+] [-] detritus|5 years ago|reply
[+] [-] poopsmithe|5 years ago|reply
It was running nice and smooth for me on the following system
Linux
Brave browser
GTX 1070 (mobile version)
i7-8700K CPU
16GB RAM
[+] [-] meepmorp|5 years ago|reply
[+] [-] soheil|5 years ago|reply
[+] [-] donclark|5 years ago|reply