Sounding rocket Rohini launched with new propellant

BANGALORE: The Indian Space Research Organisation (ISRO), earlier this month, launched Rohini Sounding Rocket (RH200) with a new propellant formulation based on Hydroxyl-terminated Polybutadiene (HTPB) from the Thumba Equatorial Rocket Launching Station (TERLS) at its Vikram Sarabhai Space Centre (VSSC).

“This was 180th successive successful flight of RH200 (meteorological) sounding rocket and the first flight with HTPB based propellant. The mission achieved an altitude of 62.7km against the predicted nominal 60.6km in 123 seconds and released the chaff payload successfully. Performance of the motor was normal,” ISRO said.

India started its space journey with the establishment of the TERLS on November 21, 1963 by launching the first sounding rocket from Indian soil. Subsequently on November 21, 1967 the first Indian made sounding rocket, RH75 was successfully launched.

“Over the years, ISRO has developed various sounding rockets for a variety of scientific experiments & meteorological studies. Currently, the RH200, RH300-MKII and RH560-MK-III rockets are operational which were developed during the early phase of our journey in rocketry,” ISRO added.

The first and second stages of the RH200 rocket are powered by solid motors. Since the inception of the RH200 rocket, both solid stages are processed using polyvinyl chloride (PVC) based propellant.

“...As compared to PVC based propellants, HTPB based propellant is more energetic with higher mechanical and interface properties and has less defects due to lower processing temperature,” ISRO said.

The space agency added that considering these advantages, efforts were made to replace PVC based propellant with HTPB based propellant for RH200 rocket and series of trials were carried out to achieve desired properties. In addition, composite paper tube based insulation has been implemented to enhance interface properties and rigidity with HTPB propellant.

“Prior to maiden flight, performance of the RH200 stages were validated by conducting four static tests for first stage and two static tests for second stage,” ISRO said.