Context: The Indian Space Research Organisation (ISRO) will achieve the 200th successful launch of Rohini RH-200 sounding rocket in the near future.

Key Points

• Rohini RH-200 has completed 198 consecutive successful flights.

• RH-200 is 3.5-metres tall, two-stage rocket.

• It is capable of climbing to a height of 70 km bearing scientific payloads.

• The first and second stages of RH-200 are powered by solid motors.

• Rohini sounding rockets are used by the ISRO for Atmospheric studies.

• The ‘200’ in the name denotes the diameter of the rocket in mm.

• For years, RH-200 rocket had used a polyvinyl chloride (PVC)-based propellant.

• But, in 2020, the first RH-200 based on hydroxyl-terminated Polybutadiene (HTPB) propellant was flown.

• Other operational Rohini variants are RH-300 Mk-II and RH-560 Mk-III.

Sounding Rockets 

• Sounding rockets are one or two stage solid propellant rockets used for probing the upper atmospheric regions and for space research.

• These are also used for a variety of experiments, including those on phenomena related to eclipses.

• The first sounding rocket, American Nike-Apache, was launched from Thumba, Kerala, in 1963.

• After that, two-stage rockets from Russia (M-100) and France (Centaure) were flown.

• The ISRO launched its own version of sounding rocket, Rohini RH-75, in 1967.