I understand there are API limitations, but isn't 15 minutes a lot for an object that orbits around the entire Earth in 90 minutes? On average you're going to be off by about a twelfth of the circumference of the Earth, or roughly the distance between Lisbon and Istanbul
At orbital speed of ~7.66 km/s, the ISS travels approximately 6,900 km during a 15-minute interval, which is indeed significant for precise location tracking.
Brilliant! This is both clever and educational. I immediately wondered if it would be possible to do something similar for JWST.
Unfortunately LOC DNS records top out at ~42 million meters (42,000 km altitude) and JWST is 38x further out (~1.5 million km away). So you can’t represent its location with a LOC altitude field. Maybe Hubble?
Not sure how that will work since JWST orbits the second Lagrange point.
It would be like asking for the GPS coordinates of the moon. NASA did test receiving weak GPS signals on the moon with LRO in 2023. It wouldn’t be useful for navigation though (not yet unless someone has like a way to do reverse GPS on the moon but not sure how that would work)
Reason this works for the ISS is because of the subsatellite point. It can receive GPS signals regardless of altitude above the Earth’s surface.
Also TLEs apply to the ISS because it’s earth orbiting.
TLEs are designed for satellites in Earth orbit, where they define position and velocity using orbital elements interpreted by models like SGP4.
> NASA did test receiving weak GPS signals on the moon with LRO in 2023.
I doubt very much that the position of the ISS in the article is being sent from the ISS at real time. It's more likely calculated using NORAD / Celestrak orbital elements plus orbital calculations.
I remember having a Windows desktop app to show the satellites locations, I'd have to download those text files to keep the information accurate. For the information beyond the snapshot, the app has to calculate distance and trajectory to estimate "If NORAD said it was here at this point in time, and heading that way with that speed, then right now it should be around here.". A bit like "If a train left Chicago 5 hours ago going 60 mph, where is it now?".
A slightly more complex, but much more responsive way would be to set an NS record of `where-is-the-iss.shkspr.mobi` that points to the IP of your VPS.
Then run a program that listens to UDP/53 and TCP/53. Have it respond with a DNS packet that's only dynamic in the LOC record and message ID. Not fully compliant with the DNS spec, but good enough for this use case.
You could cache API response to combat rate limiting.
Readit News
If you know of a DNS update which allows for per-minute updates for free, I'll happily move to it.
Remember people, DNS stands for "Definitely Not for Space-docking"
Why not setup your own name server?
Brilliant. :-D
Does Cloudflare not allow this?
I'm going to take a walk now...
Deleted Comment
Maybe a cold shower too.
Do all the tools use TXT records? Or are there any which use LOC, NAPTR, etc?
Unfortunately LOC DNS records top out at ~42 million meters (42,000 km altitude) and JWST is 38x further out (~1.5 million km away). So you can’t represent its location with a LOC altitude field. Maybe Hubble?
It would be like asking for the GPS coordinates of the moon. NASA did test receiving weak GPS signals on the moon with LRO in 2023. It wouldn’t be useful for navigation though (not yet unless someone has like a way to do reverse GPS on the moon but not sure how that would work)
Reason this works for the ISS is because of the subsatellite point. It can receive GPS signals regardless of altitude above the Earth’s surface.
Also TLEs apply to the ISS because it’s earth orbiting.
TLEs are designed for satellites in Earth orbit, where they define position and velocity using orbital elements interpreted by models like SGP4.
No problem at all, just give the location where the moon is at the Zenith and use the distance as the altitude.
> Reason this works for the ISS is because of the subsatellite point. It can receive GPS signals regardless of altitude above the Earth’s surface.
No, wether the object can actually receive GPS signals is completely irrelevant to wether its location can be described in the GPS coordinate system.
You could describe the location of the Sun in GPS coordinates too, the altitude value would just be very large.
I doubt very much that the position of the ISS in the article is being sent from the ISS at real time. It's more likely calculated using NORAD / Celestrak orbital elements plus orbital calculations.
I remember having a Windows desktop app to show the satellites locations, I'd have to download those text files to keep the information accurate. For the information beyond the snapshot, the app has to calculate distance and trajectory to estimate "If NORAD said it was here at this point in time, and heading that way with that speed, then right now it should be around here.". A bit like "If a train left Chicago 5 hours ago going 60 mph, where is it now?".
Nowadays it's all online of course: https://in-the-sky.org/satmap_worldmap.php .
That has been a very long running experiment [1]:
> University of Warwick, January 1996
[1] https://datatracker.ietf.org/doc/html/rfc1876
Then run a program that listens to UDP/53 and TCP/53. Have it respond with a DNS packet that's only dynamic in the LOC record and message ID. Not fully compliant with the DNS spec, but good enough for this use case.
You could cache API response to combat rate limiting.