Roisin,
space junk is a very real issue, and ESA are working to reduce space junk. They recently created a resource around it, which can be found with an inquiry framework at esero.ie
https://esero.ie/upcoming-workshop/engineers-week-2024-space-debris/
https://esero.ie/wp-content/uploads/2024/03/SpaceDebris.pdf
With a 1st/2nd class I would structure this inquiry as a design and make, and once the children have researched (by watching videos
such as
https://youtu.be/vU8ZwsHjvi0?si=BZ4n9fu1Kj3CUnst
or
https://www.pbs.org/video/its-okay-be-smart-space-junk/
(for a slightly older class: BBC Learning English: Junk in Space: https://youtu.be/74JqU9MNclc?si=RAMmAjcs3Ya9dhxU)
or reading)
They can carry out some simulations to check their understanding.