GRAIL-A and GRAIL-B will fly across the moon’s surface in tandem, making high-quality maps of the moon’s gravitational field.

The way that the moon’s gravity causes tides on the Earth inspired the pupils at Emily Dickinson Elementary School in the US. They wrote an essay saying that the two probes should be called Ebb and Flow, which are the names given to the falling and rising tides.

The competition was open to anyone aged 5-18 who was studying at a US school, and NASA received hundreds of entries.

The two probes are unique because this is the first NASA mission which has instruments fully dedicated to education. Ebb and Flow both carry a small camera called MoonKam, which stands for Moon Knowledge Acquired by Middle school students. Pupils across America will be able to select areas on the moon’s surface for the cameras to study.

It is hoped that Ebb and Flow will answer questions about what the inside of the moon is like, and what its temperature has been in the past.