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British Earth-observing satellites launched atop India’s PSLV booster

The PSLV-C42 mission launches from the Satish Dhawan Space Centre in Sriharikota on Sept. 16, 2018. Photo Credit: ISRO.

The PSLV-C42 mission launches from the Satish Dhawan Space Centre in Sriharikota on Sept. 16, 2018. Photo Credit: ISRO.

The Indian Space Research Organisation (ISRO) successfully launched its flagship Polar Satellite Launch Vehicle (PSLV) carrying SSTL S1-4 and NovaSAR-1—two British Earth observation satellites.

Designated PSLV-C42 in ISRO’s numbering system, the mission lifted off at 12:37 p.m. EDT (16:37 GMT) Sept. 16, 2018, from the First Launch Pad at the Satish Dhawan Space Centre in Sriharikota, India.

Preparations for the mission started in mid-July when engineers began assembling PSLV launch vehicle. The countdown campaign for the launch commenced about 33 hours before the planned liftoff. The PSLV rocket, in its core alone (CA) configuration, flew without its six strap-on motors. Shortly after launch, it began a short vertical ascent before heading in southeasterly.

The NovaSAR-1, left, and SSTL S1-4 satellites at the Satish Dhawan Space Centre. Photo Credit: ISRO/Antrix Corp.

The NovaSAR-1, left, and SSTL S1-4 satellites at the Satish Dhawan Space Centre. Photo Credit: ISRO/Antrix Corp.

Within the first two minutes of flight, the booster’s first stage finished its job and detached from the launch vehicle. Next, the rocket’s second stage assumed control over the mission, accelerating the vehicle for about 2.5 minutes until its separation some 4.5 minutes after leaving the ground.

During this phase of the mission, at about 3 minutes, 2 seconds after liftoff, the rocket’s protective payload fairing was jettisoned.

The third stage of the PSLV powered the launch vehicle for some 3 minutes, 45 seconds and was separated at 8 minutes, 9 seconds into the flight. Around 10 seconds later, the rocket’s fourth stage came to life, marking the start of the mission’s final phase.

The fourth stage continued the flight to deploy two satellites in a polar Sun-synchronous orbit (SSO) at an altitude of approximately 362 miles (583 kilometers), inclined 97.8 degrees. The separation of both spacecraft occurred 17 minutes, 44 seconds after launch.

“I am extremely happy that the PSLV-C42 precisely launched two of our customer satellites at 583 kilometer orbit,” ISRO Chairman K Sivan said during his post-launch speech. “This was unique night mission executed for the first time by us. The PSLV has proven yet again as a user-friendly vehicle in all aspects. The credit goes to the entire ISRO team and industries. This success will give added energy for industries to make PSLV by themselves. We are going to have 18 missions in the next six months, virtually one launch every two weeks.”

Built and operated by Surrey Satellite Technologies Limited (SSTL), SSTL S1-4 is a high-resolution optical Earth observation spacecraft. Weighting some 979 pounds (444 kilograms), the satellite is based on the SSTL-300S1 platform and is designed for surveying resources, environment monitoring, urban management and disaster monitoring.

NovaSAR-1, also manufactured by SSTL, is a high-resolution Earth observation satellite. It’s mission is to demonstrate the capabilities of a new low-cost S-Band Synthetic Aperture Radar (SAR) platform. With a mass of around 981 pounds (445 kilograms), the satellite is designed for forestry mapping, land use and ice cover monitoring, flood and disaster monitoring and maritime missions. The U.K. Space Agency has invested in the development of NovaSAR-1 and will benefit from access to data from the spacecraft.

“The PSLV-C42 marks the latest technology and commercial collaboration between India and the U.K. with the launch of the combination of high resolution optical and radar satellites from us,” said Martin Sweeting, Group Executive Chairman at SSTL.

The 144-foot (44-meter) tall PSLV is India’s flagship launcher. The booster is capable of lifting up to 3.25 metric tons to low-Earth orbit and about 1.42 metric tons to a geosynchronous transfer orbit (GTO). With a mass of about 230 metric tons, PSLV-CA is the lightest version of the launcher and has a capacity to launch only 1.1 metric tons to SSO. The maiden launch of PSLV-CA took place in April 2007.

Sunday’s mission marked India’s fourth launch in 2018, and the 12th flight of PSLV-CA overall. ISRO’s next two orbital missions, involving PSLV and GSLV rockets, are targeted for October, however the exact dates of the launches have yet to be announced.

Video courtesy of Space Videos



Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.

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