Rohini Sounding Rocket | 26 Sep 2022

Why in News?

The Indian Space Research Organisation (ISRO) is planning the 200^th successful launch of the Rohini RH-200 sounding rocket in a row.

• RH-200 of the Rohini sounding rocket family has completed 198 consecutive successful flights.
• The 199^th launch will happen in October 2022 during the World Space Week (4^th-10^th October) celebrations. The 200^th will take place either towards the end of October or the beginning of November 2022.

What are the Sounding Rockets?

• About:
  • Sounding rockets are one or two stage solid propellant rockets used for probing the upper atmospheric regions and for space research.
    • Sounding rockets take their name from the nautical term "to sound," which means to take measurements.
  • They also serve as easily affordable platforms to test or prove prototypes of new components or subsystems intended for use in launch vehicles and satellites.
• History:
  • The Thumba Equatorial Rocket Launching Station (TERLS) was established on 21^st November 1963. Its southern tip is close to earth's magnetic equator.
  • The launch of the first sounding rocket (American Nike-Apache) from Thumba in 1963, marked the beginning of the Indian Space Programme and was the bedrock of all the vehicles built.
  • ISRO began with the launch of indigenously built sounding rockets from 1965. The ISRO launched its own version - Rohini RH-75 - in 1967.
  • In 1975, all sounding rocket activities were cluttered under the Rohini Sounding Rocket (RSR) Programme.
  • The series of sounding rockets are called Rohini series with RH 200, RH 300 and RH 560 being the most important among them.
• RH-200:
  • RH-200 is a two-stage rocket 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.
  • For years, the RH-200 rocket had used a polyvinyl chloride (PVC)-based propellant.
  • The first RH-200 to use a new propellant based on hydroxyl-terminated Polybutadiene (HTPB) was successfully flown from the TERLS in September 2020.
    • As compared to PVC based propellants, HTPB based propellant is more energetic, higher mechanical & interface properties and has less defects due to lower processing temperature.
  • The ‘200’ in the name denotes the diameter of the rocket in mm. Other operational Rohini variants are RH-300 Mk-II and RH-560 Mk-III.

Source: TH