ISRO’s PSLV mission: Lone survivor KID capsule explained

The Indian Space Research Organisation's (ISRO) time‑tested PSLV rocket suffered a midflight malfunction during its latest mission, but Spanish spaceflight company Orbital Paradigm’s Kestrel Initial Demonstrator (KID) capsule was the lone survivor.

Hours after ISRO declared an anomaly, Orbital Paradigm posted on social media that its KID capsule had survived miraculously.

"Our KID capsule, against all odds, separated from PSLV C62, switched on, and transmitted data. We're reconstructing trajectory. Full report will come," Orbital Paradigm posted on X.

KID was one of the 16 payloads of the PSLV C62 mission and survived the mishap long enough to separate from the launch vehicle and transmit data before crash-landing on Earth.

An experimental space capsule developed by Orbital Paradigm, the KID capsule is a small-scale demonstrator for the company's future reusable space capsule dubbed Kestrel.

As an experiment, KID did not come with fully fleshed out features. It had no propulsion system of its own, nor parachutes, and it was not designed for recovery after landing.

Instead, KID's role was to separate after the PSLV rocket's fourth stage de-orbit manoeuvre and attempt to survive re-entry while transmitting data.

The KID capsule transmitted about 190 seconds of data before contact was lost, and Orbital Paradigm was able to glean several insights from it.

The Spanish company told Payload that KID separated from the PSLV rocket around 18 minutes after liftoff, likely as a result of the anomaly.

The demo craft survived peak forces of around 28Gs, while KID's thermal protection material was able to maintain a comfortable payload temperature of around 30°C, with the back, payload-facing side of the thermal protection material showing 85°C.

Speaking to the publication, Orbital Paradigm CEO Francesco Cacciatore said, "To transmit the data, it means KID had to separate undamaged from the launcher, switch on, and connect to the RF link."

"The working theory we have is that KID fell back to Earth coupled to PSLV stage 4, and the thermal conditions triggered separation," he explained.

The survival of the KID capsule and its success in transmitting data in many ways spell a success for Orbital Paradigm's first re-entry flight. That said, experiments slated to be conducted in microgravity could not be carried out due to the PSLV's failure and the premature loss of the satellite.

Although liftoff went according to plan from the space port in Andhra Pradesh's Sriharikota, ISRO soon reported an anomaly with the third stage of the vehicle.

"The PSLV is a four-stage vehicle with two solid stages and two liquid stages. The performance of the vehicle up to the end of the third stage was expected. Close to the end of the third stage, we are seeing more disturbance in the vehicle, and subsequently, there was a deviation observed in the flight path," ISRO chief V Narayanan said, while the agency said it had started a detailed analysis of the mission data.

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