Space enthusiasts are getting excited about the supermoon eclipse at the weekend but it is causing Nasa some concern.

They are worried the lack of sun will mean one of its most important spacecraft could run out of power.

Nasa's Lunar Reconnaissance Orbiter (LRO) monitors the moon.

"There are two things that happen during the eclipse; it gets very cold and there's no sun to charge the batteries," says Nasa.

What is a supermoon eclipse? A supermoon is when the moon's orbit is at its closest point to the Earth, appearing 14% larger and 30% brighter



A lunar eclipse is when the Earth comes between the moon and the sun, casting a shadow over the moon



A supermoon eclipse is when both of these things happen at the same time



The last supermoon/lunar eclipse combination occurred in 1982 and the next won't happen until 2033

The full eclipse of the moon will last more than an hour and be visible, weather permitting, at 03:11 on Monday morning.

Nasa insists it's all under control.

Noah Petro is a deputy project scientist at Nasa and has been chatting to Newsbeat from his base in America.

"With the eclipse the spacecraft will be out of direct sunlight for just about three hours," he says.

"Normally LRO recharges batteries in the sunlight so when we go into eclipse we are very cautious with the spacecraft.

"We have been through a number of eclipses over the years and know how to take care of the spacecraft."

Noah told us that they are keeping a close eye on LRO.

"We preheat the spacecraft and we turn off instruments bar one to keep the spacecraft safe.

"It's like on your phone, whenever I get the alert that I am at 20% I can turn off the wi-fi or certain applications running in the background.

"We anticipate a very smooth ride during the eclipse and a smooth recovery. We will be really prepared for it and will be ready to tackle it.

"We will be watching the battery levels and will be ready to react if something doesn't go according to plan. We will make sure it comes out of the eclipse in fine shape."

There won't be another total lunar eclipse until 2018 and there won't be a supermoon and lunar eclipse at the same time until 2033.

"It's not like the difference between an ordinary man and Superman,'' said Alan MacRobert, a senior editor at Sky & Telescope magazine.

"It really ought to be called a tiny, slightly little bit bigger moon, rather than the supermoon.''

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