- Technically , efficiency of propellants is indicated by specific impulse . Solid propellants have relatively lower specific impulse i.e. in the range of 230 seconds , liquid propellants 300 seconds and cyrogenic propellants around 450 seconds .
- The three - stage Saturn V rocket was 110m tall . It had three million parts .
- A rocket's brain does the difficult job of directing and controlling the vehicle from it's initial position on Earth to it's target location in the specified orbit .
- The brain of the rocket is known as the NGC i.e. navigation , guidance and control .
- Chandrayaan - 1 was India's first unmanned lunar probe . It was launched from Satish Dhawan Space Centre by the powerful version of PSLV , named PSLV C11 .
- There are approximately 3000 satellites currently in Earth's orbit . Some of them are very small ; some are dead ; some are discarded . The largest satellite now is the ISS i.e. International Space Station .
- AOCS i.e. Altitude and on Orbit Control System helps the satellites to stay in the desired orientation .
- Transponders are the satellite payloads for telecommunication satellites ; cameras are the payloads in Earth observation satellites .
- The diameter of the moon is 3476 km. .