PSLV: centre of attention, Pg20

• On May 18, ISRO launched PSLV-C61 carrying EOS-09 satellite; the launch failed due to a third-stage malfunction.

• The PSLV (Polar Satellite Launch Vehicle) is a four-stage rocket, designed to deploy satellites into Sun-Synchronous Polar Orbits (SSPOs).

• This failure highlights the complexity and risks of space missions, even with a workhorse like PSLV.

Detailed Insights:

• PSLV Structure:

  • Stage 1: Hydroxyl-terminated polybutadiene (HTPB) propellant, peak thrust 4.8 MN, aided by six strap-on boosters in XL version.

  • Stage 2: Vikas engine using unsymmetrical dimethylhydrazine and nitrogen tetroxide (0.8 MN thrust).

  • Stage 3: HTPB solid motor (the stage that failed during C61).

  • Stage 4: Twin engines using monomethylhydrazine and mixed oxides of nitrogen.

  • The failure in the third stage occurred due to a suspected chamber pressure loss in the motor casing. ISRO is investigating the issue and will reattempt the EOS-09 launch soon.

Key Concepts:

• PSLV (Polar Satellite Launch Vehicle): A medium-lift launch vehicle developed by ISRO for placing satellites into low Earth orbits.

• Sun-Synchronous Polar Orbit (SSPO): Orbit that passes over the same part of Earth at the same local solar time.

• Thrust: Force used to propel the rocket; measured in meganewtons (MN).

• Solid vs Liquid Propellant: Solid stages offer reliability; liquid stages provide controllability and restart capability.

Significance:

• Despite being a reliable workhorse with 98.7% success rate, the PSLV’s recent failure underscores the need for constant quality control and monitoring.

• PSLV’s flexibility makes it a key component in India’s commercial and strategic space missions.

• The EOS-09 mission is crucial for Earth observation and surveillance, with implications for civilian and military applications.

Mains Mock Question:

Discuss the significance of the PSLV programme for India's space ambitions. In light of recent failures, analyze the challenges in space launch vehicle technology.