3. What is space junk? Give two examples and describe why these materials pose hazards to
an astronaut or spacecraft.

disused satellites and other man-made debris in orbit around the earth.

"windows on the space shuttle are replaced regularly because of chipping caused by collisions with small pieces of space junk", Space debris is defunct artificial objects in space—principally in Earth orbit—which no longer serve a useful function

Explanation:

Human activities leave too many dead satellites and fragments of machinery discarded in Earth orbit

Explanation:

Example of space junks

2,000 active satellites in Earth's orbit

One in 10,000: risk of collision that will require debris avoidance manoeuvres

Disadvantage

Collision : might hit other major satellite in space

Junks in 'graveyard orbit' coming back to haunt

Space junk can hang around for centuries