February 28, 2021: The Polar Satellite Launch Vehicle (PSLV) rocket carrying 19 satellites lifted off successfully from ISRO's spaceport at Sriharikota.

At 10.24 am the rocket lifted off from the first launch pad at Satish Dhawan Space Centre (SDSC) in Sriharikota in Andhra Pradesh on Sunday. Countdown started at 8.54 am on February 27. The PSLV-C51 mission is one of the longest ones carried out by ISRO.

India's first space mission for 2021 is one of the longest for a PSLV rocket and is expected to conclude 1 hour, 55 minutes and 7 seconds into its flight.

The rocket numbered PSLV-C51 is carrying the 637-kg Brazilian satellite Amazonia-1 and 18 other satellites (including 13 from USA).

With the latest mission, India has so far slung a total of 342 foreign satellites.

The rocketing is a fully commercial one of NewSpace India Ltd (NSIL) with the primary passenger being the Amazonia-1 satellite.

Amazonia-1 is the optical earth observation satellite of National Institute for Space Research (INPE).

Amazonia-1, the primary satellite, is expected to be injected into orbit about 18 minutes after lift-off while the18 co-passenger payloads, including one from Chennai-based Space Kidz India (SKI), also engraved with a picture of Prime Minister Narendra Modi, would be launched over the next two hours.

This satellite would further strengthen the existing structure by providing remote sensing data to users for monitoring deforestation in the Amazon region and analysis of diversified agriculture across the Brazilian territory, ISRO said.

"In this mission, India and ISRO, feel extremely proud to launch the first satellite designed, integrated by Brazil. The satellite is in very good health. I congratulate the Brazilian team," said ISRO Chief K. Sivan after the lift-off.

The 18 co-passenger satellites include four from IN-SPACe (three UNITYsats from consortium of three Indian academic institutes (Jeppiaar Institute of Technology, Sriperumbudur, G.H.Raisoni College of Engineering, Nagpur and Sri Shakthi Institute of Engineering and Technology, Coimbatore) and One Satish Dhawan Sat from Space Kidz India and 14 from NSIL.

The other 14 satellites ferried on commercial basis are SindhuNetra, an Indian technology demonstration satellite and 13 satellites from the USA viz., SAI-1 NanoConnect-2, a technology demonstration satellite and 12 SpaceBees satellites for two way satellite communications and data relay.

For the third time ISRO will be using the PSLV rocket's DL variant that will have two strap-on booster motors.

This rocket variant was used the first time to put into orbit the Microsat R satellite on January 24, 2019.

The PSLV is a four stage/engine rocket powered by solid and liquid fuels alternatively with six booster motors strapped on to the first stage to give higher thrust during the initial flight moments.

The PSLV-C51 mission is one of longest ones.

The 19 satellites will be put into Sun Synchronous Orbit over duration of 1 hour, 55 minutes and 7 seconds.

During its flight, the rocket’s fourth stage engine will be cut off and restarted a couple of times, the first one will be at 16 minutes into its flight.

Just over one hour into its flight, the rocket’s engine will be restarted for about nine seconds before it is shut down again.

After 1 hour, 49 minutes and 52 seconds the rocket’s engine will be reignited for eight seconds after which the 18 piggy back satellites will be put into orbit.