The importance of prime numbers in space exploration Few days ago I've known (but since it is a difficult topic I don't know how  explain it) the importance of some prime numbers in the so-called Antikythera mechanism. See in the OEIS this A240136. There are a lot of information about this mechanism from books, journals or Internet.
I was wondering if currently prime numbers have special importance in space exploration, or the knowledge of cosmos from some relevant viewpoint.

Question. Today, currently, do prime numbers have a special importance in space exploration or the knowledge of cosmos? Are there some mechanism, technology, algorithm ... based in prime numbers essential in space exploration? Explain your answer from an informative viewpoint, and refer the literature it you need it. Many thanks.

 A: Prime numbers are used in the creation of coded masks for space telescopes.
The need for coded masks arises in telescopes that detect the gamma ray part of the spectrum, such as ESA's INTEGRAL telescope. Gamma rays cannot be focused by a lens because glass does not diffract high frequency light by a large enough angle. So instead these telescopes are pinhole cameras. The light passes through a small hole in a plate at the front of the telescope and projects onto an array of detectors at the back of the telescope. The problem is that the pinhole is very small and so does not let enough light through to form a good image. 
So instead several pinholes are used. The plate at the front of the telescope has several small holes though which the light passes, projecting several overlapping images onto the detector array. This allows more light to pass through the plate, but now the overlapping copies must be combined into a single image. It can be quite difficult to do this because each point of the detector array is exposed to light from multiple pinholes, but there are mathematical techniques for working out which light came from which pinhole and producing the single image. These techniques work better or worse depending on where the pinholes have been made in the plate. This pattern of holes across the plate is known as a coded mask. Some of the best coded masks (such as MURAs) place the holes by using prime numbers and other techniques from the field of mathematics known as number theory. The special properties of prime numbers allow the images to overlap in such a way that the overlapping images are easy to unscramble.

Prime numbers are also used in the creation of error correcting codes for transmitting information to earth from space probes.
When space probes take pictures or collect other information about space, this information must be transmitted back to earth. Because spacecraft have to have a low weight they often carry only weak energy sources. This means that the signals that they send out are very weak. The signals are then affected by interference as they travel back to earth. This means that the information we receive will be slightly different from the information that was sent. For example the binary data

11110101

might arrive as

01110101

where the first bit has changed from a $1$ to a $0$. This change is know as an error.
The solution to this problem is error correcting codes. The space probe sends its information in a redundant way so that errors can be spotted and corrected. A simple example would be the code that simply repeats every bit three times. So $01$ would be sent as $000111$. Then if an error occurs in $000$ we would instead receive $001$, $010$ or $100$. Since two of these bits are still zero we can correct the third bit back to a zero. This means that any single error will not change what we receive.
There are two important factors determining how good an error correcting code is. One factor is the rate: how much of the original data is transmitted for each bit of coded data. For example the above code made our data three times as long, so its rate is $1/3$. We want the rate to be as high as possible so that the space probe needs less time and energy to transmit its data. The other factor is how many errors can occur and still be corrected.  Our above code can only correct one error. If two errors occurred then $000$ might be received as $110$, which we would incorrectly think should be $111$. We want the code to be able to correct as many errors as possible.
The codes which space probes use have very good rates and can correct many errors. They are made using prime numbers and other bits of number theory. For example the Voyager 2 probe used the Reed-Solomon code which is based on the mathematics of finite fields. The size of a finite field is always a prime-power: a number of the form $p^n$ where $p$ is prime.
