6 ms·
Get the location of the ISS using DNS
- jamesgill 1y agoOpenNotify is another (more limited, less fancy) resource: http://open-notify.org/ http://open-notify.org/
- TMEHpodcast 1y agoBrilliant! 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 1y agoNot 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.
- TMEHpodcast 1y agoYes, I realize not-having initially understood what LOC DNS actually is. As mentioned, this could of course be applied to Hubble.
- firesteelrain 1y agoAny MEO or LEO satellite Hubble operates in LEO so it’s eligible
- netsharc 1y ago> 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 https://in-the-sky.org/satmap_worldmap.php .
- firesteelrain 1y ago> 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
- echoangle 1y agoThat doesn't matter for the problem at hand though. You can calculate the current GPS coordinates from any TLE, even if they aren't derived from GPS measurements but from Satellite Laser Ranging or some other method.
- firesteelrain 1y agoYou can derive Lat and Lon and Altitude on Earth. Thats the one point of the TLEs. But they aren’t GPS derived coordinates.
- echoangle 1y agoYes, but you don't need GPS derived coordinates for the DNS LOC entry.
- echoangle 1y ago> 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 1y agoYou 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.
- echoangle 1y ago> You can use GPS to describe a point on Earth. No, you can describe any point in the universe using GPS coordinates. You just lose some resolution the further away from earth you are because it's basically spherical coordinates (like polar coordinates but for 3D). And the system isn't inertial but earth-fixed, of course, so you would have to give the coordinates together with a time. And if you're describing the location of the moon and the sun, you would probably pick their center of gravity.
- firesteelrain 1y agoI believe this isn’t true otherwise NASA would be doing this - Earth isn’t a universal reference - GPS uses WGS84 - GPS is bound to the Earth’s surface and center - It’s Geodetic - There's no universal “equator” or “prime meridian” beyond Earth - Space uses inertial frames or celestial coordinate systems (right ascension and declination, or galactic coordinates)
- 1y ago
- dotancohen 1y agoThat probably because GSO is right about at that altitude.
- IndrekR 1y agoConsidering the ISS orbits in ~90 minutes, the 15 minute TTL is quite a long time.
- kmm 1y agoI 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
- edent 1y agoYes. 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.
- Levitating 1y ago> 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 1y agoThis 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.
- edent 1y agoI couldn't be bothered to set up a DNS server for such an ephemeral joke. But I would love to read your blog post about setting one up and what you learned.
- iwontberude 1y agoCoredns is so simple to configure and is a barebones container deployment.
- harha_ 1y agoIt's just an API that utilizes DNS, not that interesting imo.
- deleted 1y ago[deleted]
- politelemon 1y agoLooking 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?
- edent 1y agoRFCs 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".
- teddyh 1y agoSNMP sysLocation already existed, with its free-form text content. Presumably, people wanted something both more precise and machine-readable.
- echoangle 1y ago> 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.
- fouziat87 1y ago[flagged]
- huslage 1y agoCould 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 1y agoIs 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.
- croes 1y agoDepends on the hops between you and the target
- Maxious 1y agoThere's quite a few amateur radio frequencies you can interact with https://issfanclub.eu/iss-frequencies/ https://issfanclub.eu/iss-frequencies/
- trothamel 1y agoIt's pretty likely there will be a slow-scan TV event in mid-July, where the station will be transmitting images you can pick up with a radio. These are nice because you don't neeed a license - anyone with a radio that can pick up the right frequencies can receive.
- crazygringo 1y agoThat'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...
- deleted 1y ago[deleted]
- theobeers 1y agoAnother 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: 111
- timzaman 1y ago"~instantly! (...) every 15 minutes" - omg
- verytrivial 1y agoI read the opening sentence as "I love DNS erotica" which indicates I've been inside too long and should go for a walk.
- byteknight 1y agoGives a whole new meaning to its always DNS.
- deleted 1y ago[deleted]
- messe 1y agoIs that not what this is? Maybe a cold shower too.
- edent 1y agoPlease don't make me sign up as an OnlyFans creator…!
- giancarlostoro 1y agoOnlyfans was never supposed to be for porn to be fair it just kind of became the profitable business for them
- aidenn0 1y agoAny media service that doesn't ban porn will become associated with it.
- mschuster91 1y agoMeh both Reddit and Twitter have copious amounts of porn, yet neither are commonly associated with porn.
- 6thbit 1y agoYou’d be surprised but I’m pretty sure many people would dig this.
- teddyh 1y agoMore about DNS LOC records: <https://www.ckdhr.com/dns-loc/ https://www.ckdhr.com/dns-loc/>
- knadh 1y agoThis is quite cool! I just added this to dns.toys [1] dig iss.sky +short @dns.toys [1] https://dns.toys https://dns.toys
- edent 1y agoThat's so nifty! Thanks :-) Do all the tools use TXT records? Or are there any which use LOC, NAPTR, etc?
- knadh 1y agoYep, all tools return formatted strings as TXT records.
- hronecviktor 1y agoBug report for the weather: bratislava is definitely not in sub-zero C in the middle of summer. Tallinn was also ~17C off
- xyst 1y agoGreat post, definitely something I can setup on my personal recursive DNS resolver. Yet another toy I can throw on to my rpi :)
- iluvfossilfuels 1y ago[flagged]
- xkcd1963 1y agoTLDR; use an API
- ritcgab 1y agoDNS is a federated, read-optimized, geo-replicated key-value store with eventual consistency.
- supportengineer 1y ago"dig" is the new "finger"
- pvtmert 1y agoBesides the hard-coded cache, shouldn't DNS infrastructure already help with the caching just by the TTL value itself? Given quite many & large public DNS resolvers out there, like Cloudflare's 1.1.1.1 and Google's 8.8.8.8 I overall like the DNS, it is a global database with eventual consistency. Possible to store transient data. Usually not blocked by firewalls just by the sheer innocent nature. (Although gets intercepted quite a lot...)
- selcuka 1y ago> RFC 1876 is an experimental standard. That has been a very long running experiment [1]: > University of Warwick, January 1996 [1] https://datatracker.ietf.org/doc/html/rfc1876 https://datatracker.ietf.org/doc/html/rfc1876
- pul 1y agoA 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.
- edent 1y agoThe point is, I don't want to run a server. There's a globally distributed system I can (ab)use instead.
- bortzmeyer 1y agoThat would be fully compliant with the DNS spec. (I run such a service, test 2+2.op.dyn.bortzmeyer.fr/TXT or paris.now.weather.dyn.bortzmeyer.fr/TXT.)
- ygritte 1y agoRemember, kids, you can only measure either the location, or the spin. If you do both, the ghost of Werner Heisenberg will come to haunt you.