Earth Calling Spaceship: How Does Space Communication Work

“Saturn V…Saturn V..do you read..come back to the Earth '' the spaceship Saturn V, hears what the mission control wants, and starts to make its way to the landing site.

But, what if Saturn V was unable to hear what its commanders on the Earth had to say?

How does space communication even work?

Space communication is not as easy as movies and TV shows make it to be.

Astronauts cannot video call their loved ones so easily and with amazing video quality.

Space communication requires a lot of work and planning.  

But how does space communication work?

What is NASA’s Sauce Communication and Navigation program that allows data to be exchanged? 

DSN Antennas 

Spaceships and spacecraft send images and other such information from space to big antennas.

These antennas are also called DSN antennas.

They receive the details about how the spaceship is doing, or where it is.

NASA also uses the DSN to send instructions to the spaceship.

This way communication from space can work. 

The Basics

Space communications, mainly rely on two things: a receiver and a transmitter.

A transmitter encodes the message into electromagnetic waves through modulations. 

This changes the properties of the wave. This wave then flows through space to go to the receiver.

The receiver then accumulates the electromagnetic wave and deciphers it, and thus, decodes the message of the sender. 

To break it down further, let's think of a Wi-Fi router.

Each device that the Wi-Fi is connected to receives signals.

This then transmits the data from the internet. If you can imagine this, then think of space communication in the same way, but much much bigger. 

The Ground Networks

Space communications do not end there. It involves more than just pointing a spaceship’s antenna at the Earth.

NASA has worked extensively on space communication to ensure it receives all the outputs and inputs that it needs. 

a. NASA has an extensive and detailed network of antennas that are present all across the world- on all seven continents. All of these antennas receive signals from the space shuttle. However, space communications can only happen when the space shuttles pass the antennas on the ground. 

b. Space engineers or network engineers need to precisely plan communication that needs to take place between ground stations and missions. All the antennas across the globe need to be ready to receive and send data to the space shuttles. 

c. The ground station antennas have small to high-frequency ranges. There are also 230-foot antennas that help in communicating with long missions like the Voyager Spacecraft, which is 11 billion miles away. 

What Are Space Relays?

On top of direct Earth comminations, several NASA missions asap focus on relying to relay satellites to get their data to the ground.

Space stations sometimes communicate through Tracking and Data Relay Satellites (TDRS).

TDRS are satellites that are located right above the earth.

They get data from the space ships and relay it to the ground.

These transmit data to the ground stations in New Mexico and Guam. 

a. The Mars 2020 Perseverance rove will send data from Mars through the orbiters around it. 

b. Relays also provide unique advantages in regard to space communications. TDRS is placed at three different regions above the earth. This gives global coverage and continuous opportunities for space communications between Low Earth orbit missions and the ground stations. 

c. TDRS can relay data for 24 hours, and seven days a week. One doesn’t have to wait for a spaceship to pass over a ground station to receive or send data. 

Bandwidths

NASA encodes their data with different electromagnetic frequencies.

These ranges of frequencies have different capabilities.

Some are higher bandwidths.

These can carry more data to the spacecraft.

This helps the space shuttle to download the data faster. 

As of now, NASA does space communications through radio waves.

However, it is now developing different ways to communicate.

One such way could be through infrared lasers.

If they are successful, then space communication will become faster and more efficient. 

How Do Higher Data Rates Help? 

The higher the bandwidth the greater the data rates for the space missions.

Apollo radios will usually send blurry black and white video from the moon.

However, the Artemis II has a newer optical terminal that allows it to send ultra HD video from the moon or the lunar orbit. 

However, other factors can restrict the data rates. Distance is one such factor.

Distance between the transmitter and the receiver, the size of the antennas used, and also how much power is available. 

The NASA engineers need to work with all these variables to ensure that they get the best data rates possible. 

What Is Latency

Space is a huge huge area. The human mind cannot even phantom the size of space.

Thus, communications in space cannot happen immediately or instantaneously.

There is latency or delay in space communications due to the sheer distance between space ships and the ground. 

As one goes farther from Earth, latency becomes more and more evident.

If there is a spaceship near Mars, then astronauts will have to wait four minutes for their message to reach the mission control and another four minutes for them to receive the response. 

Interference

The other challenge that space communication encounters is the long distances that the message has to travel.

It also has to pass through the atmosphere.

This can cause the quality of the data to deteriorate. In some cases, the message can become garbled also. 

Radiation from celestial objects, the moon, planets, or even from other missions. This can hamper the message as well. 

To ensure that the mission control receives proper data, NASA tries to detect errors and corrects them. 

After all of this, a spaceship can communicate.

This is how space communication works, and every step has to work properly for the communication to be perfect.