Does the ISS have a phone number? Do ISS astronauts have smartphones or handsets? And does anything in the space station “ring” when an audio call is set up? We spoke to the communications experts who help the world talk to astronauts on the orbiting International Space Station
Two years ago, New Scientist invited European Space Agency astronaut Paolo Nespoli to speak to the audience at our science festival, live from the International Space Station. A handful of people at New Scientist Live in London got to put their questions to him directly, with some asking how the view of Earth has changed since he first went into space, and what advances in space exploration he anticipates in the next 20 years. Watch the video to see a recap.
As New Scientist Live 2019 kicks off next week, we were wondering how the process of setting up the video link worked. Do the ISS astronauts have smartphones or handsets? Does it “ring” when the call is set up? And does the space station have a phone number? To find out, we spoke to Chris Courtenay Taylor, a TV producer for World Wide Group who has worked for the European Space Agency for the past 20 years.
Can you call the International Space Station?
Unfortunately, it isn’t possible to call, Skype or WhatsApp the ISS. It has no phone number in the traditional sense, and astronauts have to leave their smartphones at home. For private calls, the space station has an internet-connected phone system that works through a computer, which astronauts can use to call any number on Earth. Phones on the ground cannot call them back, however.
Astronauts also have tablet computers that they can use to send emails, and although some do send tweets from orbit, these are normally emailed to their communications teams on the ground, who do the posting.
If someone does need to “call” the ISS, operators at mission control centres simply relay the audio through a telephone line to Houston into the very high frequency space-to-ground radio network. The phone number at NASA Johnson Space Center is +1 281-483-0123, but your chances of getting through to the ISS are slim.
When NASA sets up a video link to Earth like at New Scientist Live, astronauts only get to hear the audio side of the call. They don’t get to see pictures from the event. But setting up the video link and broadcasting live pictures from low Earth orbit is no easy feat.
How does the International Space Station communicate with Earth?
Since the space station crosses the horizon every 4 minutes, it is impossible to track using ground stations. To maintain the data link, NASA has a small constellation of satellites, known as Tracking and Data Relay Satellites (TDRS), which enable near constant communication between the ground and orbiting satellites. These have data rates similar to a home fibre internet connection.
Signals from TDRS are received at two NASA facilities on Earth: one at White Sands, New Mexico, and one on Guam in the Pacific. Both are connected by fibre to the main NASA communications hub.
For events in Europe, NASA’s TV desk sends the pictures via a domestic satellite to Toronto, then via a transatlantic satellite to the venue.
The lag on the pictures at such events is around 5 to 6 seconds, as a result of three sets of satellite transmissions and a conversion between video standards between the US and Europe. “That’s fine – everybody expects there to be a delay,” says Courtenay Taylor. “Five seconds is not unmanageable.”
Remarkably, it is rare for the connection to fail. Courtenay Taylor can recall only one such mishap in the past 10 years.
Communication and outreach is an important duty for astronauts, says Marco Trovatello at the European Astronaut Centre, but making time for link-ups like these is challenging. “Our ESA astronauts’ schedules are packed with science and technology experiments, ISS operations such as extravehicular activities and maintenance, so finding the slots is difficult,” he says.
It is an exceptionally busy period for the ISS right now, with three new arrivals on 25 September bringing the head count up to nine. The hectic schedule, featuring many vehicle arrivals and complex spacewalks, unfortunately made it impossible to arrange another link-up with this year’s New Scientist Live on 10-13 October.
However, we will have a talk by Ralph “Dinz” Dinsley as he explores the growth of space debris. If the growth of this space junk continues unhindered, we risk losing the most useful and economically vital orbital pathways around Earth which are used by satellites like the International Space Station.
Read more: https://www.newscientist.com/article/2218359-how-to-call-the-international-space-station/#ixzz62Oey301r