India on Sunday morning successfully placed into orbit 19 satellites including Brazil's earth observation satellite Amazonia-1-the primary passenger-in a text book style.
The multiple satellite launch space mission that lasted just under two hours was one of the longest for PSLV.
Congratulating Team ISRO for the successful mission K. Sivan, Chairman, Indian Space Research Organisation (ISRO) said, "The five Indian satellites are the result of the reform measures announced by the government earlier."
Looking forward, Sivan said, "Team ISRO's hands are full as there will be 14 space missions during 2021 that includes six satellite missions, seven launch missions and one unmanned mission -- part of India's human space mission Gaganyaan -- by the end of this year."
At 10.24 a.m. on a bright Sunday morning the 44.4 metre tall PSLV-C51 rocket blasted off from the first launch pad here laden with 14 foreign and five Indian satellites slowly rose-up towards the skies with thick orange flame at its tail.
The rocket slowly gained speed as it went up while emitting a rolling thunder sound.
Seventeen minutes into its flight the rocket first slung its primary passenger, the Brazil's Amazonia-1 into its intended Sun Synchronous Orbit (SSO).
Amazonia-1 is the optical earth observation satellite of National Institute for Space Research (INPE).
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.
India's first space mission for 2021 is one of the longest for a PSLV rocket. It took about 1 hour and 55 minutes to complete the mission.
With this successful mission India has slung a total of 342 foreign satellites into orbit, all for a fee.
The rocketing is a fully commercial one of NewSpace India Ltd (NSIL).
The 18 co-passenger satellites include four from India's 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 Satish Dhawan Sat from Space Kidz India) with an engraved picture of Prime Minister Narendra Modi as well as Bhagavad Gita in a flash.
The remaining 14 satellites are Sindhu Netra, an Indian technology demonstration satellite from Defence Research Development Organisation's (DRDO) research centre Imarat, Hyderabad to identify suspicious ships and 13 satellites from the US 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 used the PSLV rocket's DL variant that had two strap-on booster motors.
In normal configuration the PSLV is a four stage/engine expendable rocket powered by solid and liquid fuels alternatively. Six booster motors were also strapped on to the first stage to give higher thrust during the initial flight moments.
But the PSLV rocket that flew on Sunday was the DL variant having only two strap-booster motors.
This rocket variant was used the first time to put the Microsat R satellite into orbit on January 24, 2019.
The Indian space agency has PSLV variants with two and four strap-on motors, larger PSLV-XL and the Core Alone variant without any strap-on motors.
The choice of the rocket to be used for a mission depends on the weight of the satellite and the orbit where the satellite has to be orbited.
Be that as it may, the PSLV-C51 mission is one of longest one for ISRO as the satellites were placed in different altitudes.
During its flight, the rocket's fourth stage engine was cut off and restarted a couple of times, the first one was at 16 minutes into its flight.
Just over one hour into its flight the rocket's engine was restarted for about nine seconds and was shut down again.
After 1 hour, 49 minutes and 52 seconds the rocket's engine was reignited for eight seconds after which the 18 piggy back satellites were ejected into their intended orbit.