7 Wonderful Things about Space Communications, You should Know
Thursday, October 8, 2020
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People like to watch many Live TV shows but do you know how does any live show communicate? To conduct Live TV show, we need to use satellites for communication. But this looks like easy process. Most probably it is easier communication process than the communications of astronauts on far off planets for doing video chat with loved ones on Earth.
NASA shared 7 things for space communication and you will understand, how difficult space communication can be...
1. The Basics
Space communications relies on two things: a transmitter and a receiver.
A transmitter encodes a message onto electromagnetic waves through
modulation, which changes properties of the wave to represent the data.
These waves flow through space toward the receiver. The receiver
collects the electromagnetic waves and demodulates them, decoding the
sender’s message. For example, the router, which transmits data from the internet at home.
2. Ground Networks
NASA has lots of extensive network of antennas around the world to receive transmission from spacecraft. Scientists carefully plan communications between
ground stations and missions and they ensure that all antennas are ready for receiving data when any spacecraft pass over our head.
A 230-foot antenna that can communicate with far-off missions like the Voyager spacecraft, over 11 billion miles away.
A 230-foot antenna that can communicate with far-off missions like the Voyager spacecraft, over 11 billion miles away.
3. Space Relays
For communications directly to earth, many NASA missions depend
on relay satellites in order to get their data to the ground. For
example, the space station communicates through Tracking and Data Relay Satellites (TDRS), which transmit data to ground stations. The recently launched Mars 2020 Perseverance rover will send data through orbiters around Mars, which forward the data to Earth.
Relays offer unique advantages in terms of communications availability. For example, the placement of TDRS at three different regions above Earth offers global coverage and near-continuous communications between low-Earth orbit missions and the ground. TDRS users can relay data 24 hours a day, seven days a week.
Relays offer unique advantages in terms of communications availability. For example, the placement of TDRS at three different regions above Earth offers global coverage and near-continuous communications between low-Earth orbit missions and the ground. TDRS users can relay data 24 hours a day, seven days a week.
4. Bandwidth
NASA encodes data on various bands of electromagnetic frequencies. These
bandwidths have different capabilities.
Higher bandwidths can carry more data per second, allowing spacecraft to
downlink data more quickly.
Currently, NASA relies primarily on radio waves for communications, but the agency is developing ways to communicate with infrared lasers. This type of transmission will offer missions higher data rates than ever before.
NASA’s Laser Communications Relay Demonstration (LCRD) will showcase the benefits of optical communications. The mission will relay data between ground stations over optical links, testing their capabilities. NASA will also furnish the space station with an optical terminal that can relay data to the ground via LCRD.
Currently, NASA relies primarily on radio waves for communications, but the agency is developing ways to communicate with infrared lasers. This type of transmission will offer missions higher data rates than ever before.
NASA’s Laser Communications Relay Demonstration (LCRD) will showcase the benefits of optical communications. The mission will relay data between ground stations over optical links, testing their capabilities. NASA will also furnish the space station with an optical terminal that can relay data to the ground via LCRD.
5. Data Rates
Higher bandwidths can mean higher data rates for missions. Apollo radios sent grainy black and white video from the Moon. An upcoming optical terminal on the Artemis II mission will send 4K, ultra-high definition video from lunar orbit. But bandwidth isn’t the only constraint on data rates.
Other factors
that can affect data rates include the distance between the transmitter
and receiver, the size of the antennas or optical terminals they use,
and the power available on either end. NASA communications experts must balance these variables in order to maximize data rates.
6. Latency
Communications don’t occur instantaneously. They’re bound by a universal
speed limit: the speed of light, about 186,000 miles per second.
However, farther from Earth, latency can become a challenge. At Mars’ closest approach, about 35 million miles away, the delay is about four minutes. When the planets are at their greatest distance,about 250 million miles away, the delay is around 24 minutes. This means that astronauts would need to wait between four and 24 minutes for their messages to reach mission control, and another four to 24 minutes to receive a response.
7. Interference
As communications transmissions travel over long distances or through
the atmosphere, the quality of their data can deteriorate with noisy messages. Radiation from other missions, the Sun, or other celestial
bodies can also interfere with the quality of transmissions.
To make sure that mission operations centers receive accurate data, NASA uses methods of error detection and correction. Methods of error correction include computer algorithms that can interpret noisy transmissions as usable data.
To make sure that mission operations centers receive accurate data, NASA uses methods of error detection and correction. Methods of error correction include computer algorithms that can interpret noisy transmissions as usable data.
For More-www.nasa.gov
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