Countdown Begins For ISRO’s 101st Space Launch PSLV-C61 Mission

Photo of PSLV-C61 EOS-09 (ISRO's X)

The 12-hour countdown for the launch of Indian Space Research Organisation's (ISRO) earth imaging satellite Polar Satellite Launch Vehicle (PSLV) rocket commenced on Saturday, in Sriharikota, tweeted ISRO. 

The lift-off for the PSLV-C61, carrying Earth Observation Satellite (EOS-09) satellite for earth imaging, scheduled to take place at 5.59 a.m. from the First Launch Pad (FLP) at the Satish Dhawan Space Centre on May 18, will also mark the 101st mission for the agency. 

Taking to the X ISRO tweeted, "T-12 hours to ISRO’s 101st space launch PSLV-C61 is mission-ready..."

 T-12 hours to ISRO’s 101st space launch

PSLV-C61 is mission-ready

18 May 2025 | 5:59 AM IST |
FLP, SDSC SHAR

Live from 5:29 AMhttps://t.co/JTNzdc0QGP

More information: https://t.co/cIrVUJxcTZ#ISRO #Countdown #PSLVC61 pic.twitter.com/dnd5n0pFF6

— ISRO (@isro) May 17, 2025

PSLV-C61 marks the 63rd flight of the Polar Satellite Launch Vehicle and the 27th using the PSLV-XL configuration. This mission continues the PSLV's record of delivering reliable performance across a wide range of payloads and orbits, said ISRO. 

The agency further stated that after EOS-09 is deployed, Orbit Change Thrusters (OCT) will be used to reduce the altitude of the PS4 stage, followed by passivation to limit its orbital life — a step aligned with responsible space operations.

Weighing around 1,696.24 kg, the EOS-09 satellite has a mission life of 5 years and includes deorbiting fuel for safe post-mission disposal. The mission will place the Earth Observation Satellite into a Sun Synchronous Polar Orbit (SSPO). 

The EOS-09 (RISAT-1B) is a follow-on to the RISAT-1 satellite which is equipped with similar configuration. It complements and supplements data from the Resourcesat, Cartosat and RISAT-2B Series satellites.

The EOS-09 satellite is a cutting-edge Earth observation satellite designed to bolster India's space-based surveillance capabilities. Fitted with advanced C-band synthetic aperture radar technology, it can capture high-resolution images of the Earth's surface regardless of weather conditions or time of day. This capability enables effective monitoring and management across various sectors.

Earlier, Union Minister Jitendra Singh hailed this mission and tweeted "We’re now one step closer to liftoff on 18 May..."

Watch this incredible timelapse of PSLV-C61 / EOS-09 as it rolls from the Payload Integration Facility (PIF) to the Mobile Service Tower (MST) at SDSC-SHAR, Sriharikota — a crucial step in #ISRO’s 101st launch mission.

Each frame captures the precision, teamwork & engineering… pic.twitter.com/KjAm7ncVee

— Dr Jitendra Singh (@DrJitendraSingh) May 16, 2025

Meanwhile, ISRO Chairman V. Narayanan stressed the critical role of satellite technology in national security and governance, stating, "With the PSLV-C61/EOS-09 mission, ISRO continues to demonstrate its commitment to both technological excellence and the national interest."