The heaviness of rockets, why it matters in space flight

Last Updated29/10/2022

ISRO recently crossed an important milestone with the successful launch of the LVM3 M2/OneWeb India-1 mission.
LVM3 rocket carried ~ 6 tonnes of payload into LEO, the most that any ISRO mission has delivered into space till date.

Re-validated viability of LVM3 rocket for major missions like Gaganyaan.
Affirmed ISRO’s claim as a serious player in heavy satellite launch market.
Very few countries have capability to launch satellites weighing > 2 tonnes.
Ended ISRO’s dependence on Ariane rockets of Europe to launch its heavy satellites.

This is image title

India currently has 3 operational launch vehicles:
Polar Satellite Launch Vehicle or PSLV
- Most commonly used
- Carried as many as 53 successful missions since 1993.
- Only two flights have failed.
Geosynchronous Satellite Launch Vehicle or GSLV Mk-II
- Used in 14 missions
- 4 ended in failures
Launch Vehicle Mark-3 or LVM3
- 5 missions, including the Chandrayaan 2 mission
- Never failed.
ISRO has also been working on a reusable launch vehicle (RLV).
Can be brought back & refurbished for use multiple times.

Size of a launch vehicle decided by:
Its destination in space
kind of fuel — solid, liquid, cryogenic, mix
size of the payload
Choice of any two of these variables places severe restrictions on flexibility of the third.
Most of a rocket’s energy is burnt in travelling to the lower earth orbit.
Reason: Force of gravity is the strongest here.
If a space mission is headed towards any celestial body, the gravity of the destination also matters.
More energy would be expended in reaching such a destination.