The space station is 400 KM away but the signals travel 35 thousand KM to reach us… This is how astronauts communicate with Earth

New Delhi: American Space Agency National Aeronautics and Space Administration astronaut and Indian-origin woman Sunita Williams has returned to Earth. Her landing on Earth took place at 3:30 am Indian time.

With this landing of Sunita Williams, a historic space mission was completed. Now the question arises that Sunita Williams was on the International Space Station for about 9 months, which is located at an altitude of about 400 kilometers from the surface of the Earth, so how does NASA and ISS communicate?

Today we are going to tell you about NASA’s communications system and the way to contact ISS.

Nasa has many ground stations
NASA has many ground stations, which it uses for communications. It has a special communication system called Tracking and Data Relay Satellite System and its main stations on earth are in New Mexico and Guam.

Signals are sent to TDRS satellites 35 thousand km away
These ground stations send signals to TDRS satellites, which are present at a height of about 35,786 km from the earth. After that, these satellites send signals to ISS. During this, the signals work at the speed of light, whose speed is 3 lakh kilometers per second, so it takes only 1.4 milliseconds to transmit the signal from earth to ISS and it takes a total of 2.8 milliseconds for the signals to come and go from both sides.

ISS’s Communications System
TDRS Satellites (Relay System): These satellites receive signals from the ground stations and transmit them to ISS. These satellites revolve around the earth and maintain constant contact despite the changing position of ISS.

ISS communication system
The ISS has many antennas and communication devices, such as band systems and they include voice, telemetry, etc. Ku-band system is used for high-rate data, video and scientists.

VHF radio for spacewalk
Apart from this, there is VHF radio, which is used for direct voice contact with astronauts during spacewalk.

Return to Earth
Signals from the ISS are sent back to Earth through the same TDRS satellite system. After this, astronauts communicate with the NASA station.