Get the location of the ISS using DNS
63 comments
·July 6, 2025kmm
edent
Yes. As I say in the post, you shouldn't use this for docking operations.
If you know of a DNS update which allows for per-minute updates for free, I'll happily move to it.
dahsameer
> As I say in the post, you shouldn't use this for docking operations
Remember people, DNS stands for "Definitely Not for Space-docking"
Levitating
> If you know of a DNS update which allows for per-minute updates for free, I'll happily move to it.
Why not setup your own name server?
zdw
This is the correct way - dynamic DNS servers frequently have very low TTLs set.
Serving DNS yourself is such an incredibly small bandwidth impact - most of the packets are in the 10's to 100's of bytes - and authoritative DNS servers do not do a lot of processing, just send back RR's from zones which are read at boot time, or updated in an in-memory database.
AdieuToLogic
> As I say in the post, you shouldn't use this for docking operations.
Brilliant. :-D
fouronnes3
You totally could use it for docking. A real ISS docking manoeuvre takes several hours. Orbits are very predictable and I'm quite confident that the error you'd get projecting your orbit 15min into the future would be good enough to get within close radar range for the final approach. In fact you probably could do it, even if your spavecraft doesnt have DNS at all, and you have to do the DNS resolve from a ground laptop before you board it. Soyez can dock within 3 hours of lauch. Orbits are very predictable in this timeframe.
Abekkus
Cloudflare does this with an API. If you have any money, I'd suggest dnsimple.com instead.
metafunctor
It’s quite easy to run your own DNS server — I've found it a worthwhile exercise. Of course, you’ll need a server to run it on.
echoangle
> If you know of a DNS update which allows for per-minute updates for free, I'll happily move to it.
Does Cloudflare not allow this?
Abekkus
I'd say the API can take up to half a minute to propagate, so API updates every minute is running up against their own performance. If you're a free customer, they may block you after a while, but first they'd have to notice you, and I doubt one update per minute would bother them.
verytrivial
I read the opening sentence as "I love DNS erotica" which indicates I've been inside too long and should go for a walk.
6thbit
You’d be surprised but I’m pretty sure many people would dig this.
cmehdy
The numbers would definitely be setting A record in that domain!
theobreuerweil
If that’s a pun, it’s next level
null
messe
Is that not what this is?
Maybe a cold shower too.
edent
Please don't make me sign up as an OnlyFans creator…!
giancarlostoro
Onlyfans was never supposed to be for porn to be fair it just kind of became the profitable business for them
aidenn0
Any media service that doesn't ban porn will become associated with it.
byteknight
Gives a whole new meaning to its always DNS.
theobeers
Another record, Name Authority Pointer (NAPTR), has the telephone number of the Johnson Space Center in Houston:
> dig where-is-the-iss.dedyn.io NAPTR
; <<>> DiG 9.10.6 <<>> where-is-the-iss.dedyn.io NAPTR
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31786
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;where-is-the-iss.dedyn.io. IN NAPTR
;; ANSWER SECTION:
where-is-the-iss.dedyn.io. 3600 IN NAPTR 100 100 "u" "E2U+voice:tel" "!^.*$!tel:+12814830123!" .
;; Query time: 84 msec
;; SERVER: 100.100.100.100#53(100.100.100.100)
;; WHEN: Sun Jul 06 10:53:39 EDT 2025
;; MSG SIZE rcvd: 111knadh
This is quite cool! I just added this to dns.toys [1]
dig iss.sky +short @dns.toys
TMEHpodcast
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?
firesteelrain
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.
echoangle
> It would be like asking for the GPS coordinates of the moon
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.
firesteelrain
You can use GPS to describe a point on Earth. To use the moon or sun is kind of weird because of their size to use GPS coordinates for this
I was referring to finding your position on the moon using Earth referenced GPS signals.
netsharc
> 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?".
Nowadays it's all online of course: https://in-the-sky.org/satmap_worldmap.php .
firesteelrain
> 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.
Yes, this is how the referenced site knows the approximate position of the ISS via TLEs. TLEs are updated regularly for space objects
TMEHpodcast
Yes, I realize not-having initially understood what LOC DNS actually is. As mentioned, this could of course be applied to Hubble.
firesteelrain
Any MEO or LEO satellite
Hubble operates in LEO so it’s eligible
teddyh
More about DNS LOC records: <https://www.ckdhr.com/dns-loc/>
politelemon
Looking at the RFC it's never explained why this is needed. Or was needed back in 1996, perhaps something to go with universities and data center logistics back then?
echoangle
> Looking at the RFC it's never explained why this is needed.
Chapter 5.1 (Suggested Uses) has at least some vague suggestions:
> Some uses for the LOC RR have already been suggested, including the
> USENET backbone flow maps, a "visual traceroute" application showing
> the geographical path of an IP packet, and network management
> applications that could use LOC RRs to generate a map of hosts and
> routers being managed.
edent
RFCs are, in my experience, vague about the problem they're attempting to solve.
There's no reason this couldn't be a human-readable string like "42 Wallaby Way, Sidney".
null
timzaman
"~instantly! (...) every 15 minutes" - omg
huslage
Could you calculate the position from the Ephemeris data in realtime instead of using an API? This would allow you to return the current location on every request potentially.
lordnacho
Is there any service on the ISS that the public can interact with? Maybe you could use response times to figure out where it is that way.
crazygringo
That's what I thought this was going to be from the title -- some kind of DNS response time triangulation from a device on the ISS itself, because DNS was allowed past a firewall or something...
It's still a fun little project, but definitely feeling a little disappointed in comparison to what the title felt like it suggested to me...
Maxious
There's quite a few amateur radio frequencies you can interact with https://issfanclub.eu/iss-frequencies/
croes
Depends on the hops between you and the target
null
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