1 What is space junk - how is this a hazard to space flight?

2. NASA and other space agencies track space junk - how many individual objects do they track? Are there objects they cannot track?

3. Have there been any debilitating collisions with space junk- if so identify these incidents

4. What is the process is known as collisional cascading, or the Kessler effect ?

5. Private companies are currently the largest supplier of rockets and satellites - do they have any legal responsibility to limit space junk?

In 1987 the World Commission on Environment and Development defined sustainable development as meeting the needs of the present generation without compromising the ability of future generations to meet their needs.

6. Is our access to space becoming more or less sustainable? Does it matter?

7. What would change in our world without the ability to use satellites and the ability to put them or ourselves into space?