6) What are the total(estimated) satellites that have been launched since 1954? How many are defunct and how many functional?

7) Inter-satellite handover is not very common in satellites.

8) The electricity for a space shuttle orbiter is generated by that combine stored ...and oxygen.

9) Discuss and describe characteristics and different part of a space station such as International Space station.

10) What is space debris and how this issue will affect our space utilization in the near future?