So, imagine that you urgently need to contact the rover located on Mars. How can this be done? In order for humanity to have the opportunity to even visit Mars virtually, the signal sent from the Earth must pass at least fifty-five million kilometers! Even with such a distance, which is considered the smallest and happens once every 15-17 years during the Great Confrontation, the delay in the received signal will be about 3 minutes. So how then can you get through to Mars and preferably without interference?
How are Mars rovers driven from Earth?
Despite the fact that the planet Mars is very far from us, rovers created by man are already plowing its rusty surface. These small devices not only take full-color images, but also transmit a huge amount of scientific data to Earth.
In order for us to enjoy panoramic photographs of the Martian landscape, scientists have created a real system that allows us to track the entire process of transmitting data received on the Red Planet.
So, most often in the process of transmitting data from Mars, 3 main figures are involved – the center of space communications located on Earth, the satellite located in the orbit of Mars and the rover itself.
Due to the fact that the planet Earth rotates very quickly around its axis, to ensure a continuous signal from Mars, we need to have several points for receiving and transmitting data. These points are called DSNs. The stations are located in the USA, Spain and Australia, and when our planet turns in the opposite direction, the signal is simply transferred from one station to another, allowing it to control the spacecraft 24 hours a day.
The most commonly used station for communication with rovers is the DSN station, located near the capital of Australia, Canberra. This complex has three active antennas of different sizes: DSS-34 and DSS-45, whose diameters are 34 meters, and DSS-43, whose size exceeds 70 meters.
In general, the station performs 4 different functions. So, in order to receive a clear signal coming from Mars, the Canberra station should not only receive encrypted data, but also monitor the possibility of communication between the two planets, process the data, transfer control commands of scientists to the rover and monitor the systems of the DSN station itself.
All information that must be received on the rover is sent to the DSN station, from where it is sent on a space trip to the distant "Red Planet". The signal goes to the planet in about 5-10 minutes, provided that Mars is at a relatively close distance from Earth, after which it is caught by an orbiting Martian satellite, which sends the encoded signal to the receiver of the rover.
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All rovers are equipped with special antennas, each of which is used to receive and transmit data. So, the Curiosity rover is equipped with three antennas at once, each of which has its own functions. The LGA antenna is responsible for receiving information, the UHF antenna is most often used for data transmission, and the HGA equipment is responsible for receiving commands for controlling the rover.
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Sometimes the rover generates so much information that it is not always possible to send all the useful data to Earth. In order to solve this problem, NASA experts set priorities of importance, because of which part of the data is simply deleted before reaching our planet.
Do you need satellites to contact Mars?
As we found out earlier, for communication with rovers we need to use satellites in the orbit of the "Red Planet". Each of these satellites communicates with the rover through special communication windows, which usually last only a few minutes. Despite the short interaction time, this time is enough to transfer all the necessary amount of information.
If until 2006 the Odyssey satellite performed the signaling work, then at present the new Mars Reconnaissance Orbiter or MRO satellite is working with it. In addition to having a very impressive arsenal of state-of-the-art scientific instruments, MRO is equipped with the latest HiRISE camera, which allows you to take high-resolution images.
DSN stations are in communication with the MRO for about 16 hours a day, since the rest of the time the satellite is on the back of Mars and is closed from signal transmission by the thickness of the planet.
Despite the apparent simplicity of the process, the cost of one hour call is currently approximately $ 10,000. So, if one day you suddenly want to make a call to a future Martian colony, then first you have to collect a decent amount. Well, after reading this article, you will at least know why your call will cost such a lot of money.
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