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You may have heard of freeze-dried sweets.

In fact, some of you may have seen or even tasted some.

With a huge rise on social media platforms, many shopping experts say it's one of the biggest new sweet trends in recent times.

But what are freeze-dried sweets and what have they got in common with astronauts?

Keep reading to find out more and let us know in the comments if you've tried them.

Freeze-drying food isn't a new process.

The most popular food items that can be freeze-dried are fruits and vegetables. In fact, most of the fruit that you find in your breakfast cereal has been freeze-dried.

However, other products like meat and dairy can also be dehydrated using the same process.

As the name suggests, it's a way of preserving food by freezing and then drying it in order to get rid of the moisture.

In order to do so, food is usually frozen quickly and then placed into a vacuum chamber, where any water still in the item can be removed quickly in order to dry it out.

Freeze drying allows food to last for much longer, without losing flavour or nutritional value.

In the early days of the space program, one of the many problems for experts was working out how to feed astronauts during their time away from Earth.

As missions could often last many months, food needed to be long lasting, and it needed to be light and easy to pack and prepare.

US space agency Nasa decided to look into a number of different possible food preservation techniques to find out which one would be best.

One of the techniques they developed was freeze drying.

This meant that nutritious food could be sent to space, which astronauts could then easily rehydrate by adding water.

According to Nasa, these days, the International Space Station is equipped with lots of appliances such as freezer, an oven, a microwave.

There are also plenty of other tools on board to help store and prepare fresh food - however freeze-drying continues to play an important role.