I find this kind of surprising. First off, I'd figure that NASA would set up a few UHF stations around the world in locations with decent internet access (friendly countries or military bases), and route comms via that. Maybe you don't have total coverage, but at least you don't have to wait an hour before it's back over the US.

Secondly, there many more options available than TDRSS or UHF. Amateur radio enthusiasts frequently make contact with astronauts (2 meter and 70cm bands, IIRC). While that doesn't really solve the blackout problem, I find it hard to imagine that there isn't a lower-frequency radio which could maintain voice contact with the ISS.

I believe NASA does have a few UHF stations elsewhere, or at least used to. As of a 1998 document about the shuttle program [1], they listed 6 UHF air-to-ground stations, 3 of them in other countries. The U.S.-based ones were in Guam, Hawaii, and Florida; and the others were in Ascension Island (a British dependency halfway between Africa and South America), Bermuda (a British dependency off the east coast of Canada), and Dakar, Senegal.

[1] http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/s...

Just a clarification: Bermuda is not really close to any major coastline, and certainly not the Canadian one.

https://www.google.com/maps/place/Bermuda/@31.2546129,-41.52...

850 miles (closest point is in North Carolina) isn't necessarily far.

When someone says "off the coast", I would not expect 850 miles of distance. And, even more, when they say "off the east coast", I would not expect it to be almost directly south of the east coast. Those were the points I was attempting to relay.

Other more obscure methods of communicating with the ISS include the Russian Lira and Regul systems as well as the Japanese Ka-band dish on the external lab.

Losing all communications with the ISS doesn't happen frequently though does it? Almost never from what I can tell.

http://www.nasa.gov/mission_pages/station/expeditions/expedi... Seems like the last time it happened and it was big news. I can't imagine how scary it would be to be in space without any way to communicate with earth. I guess the crew return vehicle would still be usable and the station would still operate as normal for a good while, but it would still be very scary.

Here are some links to the live status of those systems:

http://spacestationlive.nasa.gov/displays/cronusDisplay2.htm... UHF

http://spacestationlive.nasa.gov/displays/cronusDisplay3.htm... S-band

http://spacestationlive.nasa.gov/displays/cronusDisplay4.htm... Ku-band

Click "Show Table" in the bottom right corner of that page to see the raw data for each display.

It would be nice to see some data-rate stats on those connections. Also a better dashboard would be fun to build for the ISS, some interesting data points are available.

Also apparently the high-speed Ku-band is available about 50% of the time. http://www.reddit.com/r/IAmA/comments/18pik4/i_am_astronaut_...

Can't speak for S-band, but Ku-band data rates are 25 Mbps Earth-to-ISS and 300 Mbps ISS-to-Earth, which is the maximum supported by TDRSS Ku-band links. Data rates may drop a bit depending on the individual satellite involved, configuration, etc.

Pretty much - call that antenna gain, it's much cheaper to put bigger and better hardware on the ground. Recall though that the signal still goes through a TDRSS satellite, which also has a bigger dish.

unrelated to the ISS but might be interesting to some people http://eyes.nasa.gov/dsn/dsn.html

The fact that we can talk to something 15 billion km away is mind-blowing.

It makes light (at 1 billion km per hour) seem slow.

More mindblowing? I, Joe Sixpack, can see the current Deep Space Network status overview (your URL) from my bedroom whilst in my underwear. Science!

You can see when the ISS is in range by watching the live video stream. From what I have seen it's rarely out of contact and they obviously have bandwidth to spare for that.

Elaborating on TDRSS a little bit - the ISS has allotments on both S- and Ku-band transponders (there are several per satellite) and hands off between satellites (TDRSS is geostationary) as it orbits, it's rare that another TDRSS customer has something important enough going on that the ISS gets no allocation at all for more than an orbit.

IMHO, the real application for laser communications is for high bandwidth inter-satellite links.

> IMHO, the real application for laser communications is for high bandwidth inter-satellite links.

Iridium-esq constellations.

One of the side effects of the laser is that only the receiving station it is pointed to can receive it. That is both good and bad, if you're partners running the ISS don't trust you, they might worry about what you're sending on the communication channel that they cannot hear.