ISRO’s 101st Mission: When Ambition Met Reality
On May 18, 2025, ISRO’s PSLV-C61 rocket lifted off from Sriharikota, carrying the EOS-09 satellite—a cutting-edge Earth observer designed to revolutionize disaster management and agriculture. But a third-stage malfunction shattered hopes, marking ISRO’s third PSLV failure. Here’s a detailed breakdown of what went wrong and why it matters.
The PSLV-C61 Mission: By the Numbers
A quick glance at the mission’s critical stats:
| Parameter | Details |
|---|---|
| Mission Number | ISRO’s 101st launch |
| Rocket Configuration | PSLV-XL (27th flight) |
| Height & Mass | 44.5 meters tall |
| Payload | EOS-09 satellite (1,696 kg) |
| Target Orbit | Sun Synchronous Polar Orbit (597 km altitude, 97.51° inclination) |
| Cost of Failure | Lost SAR imaging capabilities for agriculture, disaster response & security |
EOS-09: The Satellite That Never Reached Its Home
The EOS-09 wasn’t just another satellite—it was India’s high-tech “Earth Guardian.” Here’s what made it special:
| Feature | Specification |
|---|---|
| Core Technology | C-band Synthetic Aperture Radar (SAR) |
| Key Capabilities | All-weather, day-night imaging |
| Design Heritage | Built on RISAT-1 satellite bus |
| Mission Lifespan | 5 years (with deorbiting fuel reserved) |
| Unique Selling Point | 3x better image frequency than predecessors |
The 8-Minute Flight That Ended in Despair
A minute-by-minute timeline of the mission’s critical phases:
| Time Since Launch | Event | Outcome |
|---|---|---|
| 0:00 | Liftoff | Nominal |
| 1:51 | First stage separation | Successful |
| 2:44 | Second stage ignition (Vikas engine) | Nominal |
| 4:36 | Third stage ignition | ANOMALY DETECTED: Chamber pressure drop |
| 8:23 | Fourth stage ignition (planned) | Never activated |
| ~15:00 | Mission declared unsuccessful | Satellite lost in wrong orbit |
The Culprit: Third-Stage Motor Pressure Drop
The mission’s fatal flaw occurred 4.5 minutes into the flight. The third-stage solid motor’s chamber pressure fell abruptly, starving the rocket of thrust. This stage was critical for achieving orbital velocity. Without it, EOS-09 couldn’t reach its designated altitude, rendering it useless for Earth observation.
Space Debris Mitigation: The Unsung Hero
Despite the failure, ISRO’s responsible design choices stood out:
- Fourth Stage Deorbiting Plan: Fuel reserved to lower PS4 stage orbit for faster atmospheric reentry.
- EOS-09’s Built-in Safety: Satellite carried extra fuel to deorbit itself within 2 years of mission completion.
- Global Impact: Aligns with UN’s 2030 Space Debris Mitigation Guidelines.
3 Lessons from ISRO’s 3rd PSLV Failure
- Solid Motors Need Scrutiny: Previous PSLV failures (1993, 2017) also involved solid-stage issues.
- Testing Over Success Rate: ISRO’s 94% success rate is stellar, but 100% is non-negotiable for national security payloads.
- Transparency Wins Trust: Immediate anomaly acknowledgment builds public confidence.
Read in Depth: The Technical Details of the Mission from ISRO.
What’s Next for ISRO?
- Failure Analysis Committee: Engineers will reverse-engineer telemetry data to pinpoint the pressure drop cause.
- PSLV-XL Redesign: Possible reinforcements to third-stage motor casing.
- EOS-09 Replacement: A new satellite could launch by late 2026.
Conclusion: Failure Is the Stepping Stone
While the ₹365 crore mission’s loss stings, ISRO’s legacy of resilience remains intact. As Chairman S. Somnath stated: “Every anomaly teaches us how to protect tomorrow’s missions.” For a nation eyeing Venus and Mars, this stumble is but a comma—not a full stop.
Also Read: World Hypertension Day 2025: 10 Life-Saving Strategies to Conquer the Silent Killer