The Indian Space Research Organisation (ISRO) is steering towards a significant achievement with the 200th successful launch of the Rohini RH-200 sounding rocket. The Rohini RH-200, a part of the well-known family of sounding rockets, has accomplished 198 back-to-back triumphant flights. The organisation has planned the 199th and 200th launches to take place consecutively in October and November 2022, with the former coinciding with World Space Week celebrations running from 4th to 10th October.
An Overview of Sounding Rockets
Sounding rockets, typically one or two stage solid propellant rockets, are key instruments for exploring the upper atmospheric regions and performing space research. They derive their name from the nautical term “to sound,” meaning to take measurements. Besides their primary role, sounding rockets serve as cost-effective platforms for testing and validating prototypes of novel components or subsystems designed for usage in launch vehicles and satellites.
The Journey of Sounding Rockets in India
The historical journey of Indian Space Programme took off with the launch of the first sounding rocket, an American Nike-Apache, from the Thumba Equatorial Rocket Launching Station (TERLS) in 1963. Located near Earth’s magnetic equator, TERLS was officially established on 21st November 1963 and has since been a crucial launch pad for sounding rockets. Starting in 1965, ISRO began launching indigenously built sounding rockets, kick-starting with its own Rohini RH-75 in 1967. By 1975, all activities related to sounding rockets were consolidated under the Rohini Sounding Rocket (RSR) Programme.
Introducing the Rohini Series
Named the Rohini series, this range of sounding rockets has made a significant contribution to space research in India, with RH-200, RH-300, and RH-560 being the key players. The Rohini RH-200, a two-stage rocket, is capable of reaching an altitude of 70 km carrying scientific payloads. The first and second stages are empowered by solid motors. Initially, the RH-200 rocket utilised a polyvinyl chloride (PVC)-based propellant; however, it shifted to a new propellant based on hydroxyl-terminated Polybutadiene (HTPB) in September 2020. This HTPB based propellant, exhibiting higher energy, superior mechanical & interface properties, and fewer defects due to lower processing temperature, replaced the PVC based propellants. The ‘200’ in RH-200 denotes the diameter of the rocket in millimeters.
The Diverse Fleet of Operational Rohini Rockets
Beyond RH-200, the Rohini series features other operational variants like the RH-300 Mk-II and RH-560 Mk-III. Here’s a quick glance at some details of these sounding rockets:
1. RH-200:
– Payload: 10 Kg
– Altitude: 80 Km
– Purpose: Meteorology
– Launch Pad: Thumba
2. RH-300-Mk-II:
– Payload: 60 Kg
– Altitude: 160 Km
– Purpose: Aeronomy
– Launch Pad: Balasore
3. RH-560-MK-II:
– Payload: 100 Kg
– Altitude: 470 Km
– Purpose: Aeronomy
– Launch Pad: SDSC-SHAR
Conclusion
The ISRO’s journey towards its 200th successful launch of the Rohini RH-200 sounding rocket underscores India’s advancement in space research and development. The Rohini series, the backbone of this progress, continues to contribute significantly to improved understanding of our upper atmosphere and space.
