Thread by @Chethan_Dash

Here We Go: #Update #Thread

As #GSLVMk3 or #LVM3 prepares for its second commercial launch, @isro efforts on enhancing its weight-lifting capacity is gaining pace. I hear that the qualification tests for semi-cryo (SC120) are expected to be completed in a couple of months. 1/n

https://twitter.com/Chethan_Dash/status/1586948636054650880

#GSLVMk3 is India’s heaviest rocket yet. Here’s some perspective: Between May 26, 1999 and Oct 22, 2022, @isro launched 345 foreign satellites, all on #PSLV, which together weigh 9,326.4kg. On Oct 23, 2022, in its first commercial mission, #LVM3 launched 5,796kg. 2/n

Of course, these missions are incomparable given that most of the foreign satellites launched by PSLV were ride-sharing payloads and include tens of small, micro and nano satellites… 3/n

…But there’s no doubt that the Mk3 clearly enhances India’s prospects. In fact, Isro chairman S Somanath said last week: “The GSLV-Mk3 is India’s best commercial bet.” 4/n

At present, #GSLVMk3 can carry around 4 tonnes to a GTO and at least 6 tonnes to LEO. Induction of the high propulsive SC120, along with increased propellant loading of the cryogenic upper stage (CUS) can enhance this to 6 tonnes (GTO) and 10 tonnes (LEO). 5/n

Isro spokesperson Sudheer Kumar said: “GSLVMk3 prog was envisaged to eventually carry at least 10 tonnes to LEO & 6 tonnes to GTO. We’ll achieve this with an upgrade of CUS with additional propellant loading & induction of semi-cryo stage that will replace L110…” 6/n

“...Work on semi-cryo engine is almost nearing completion. Qualification tests are in progress. Stage & engine devp phase is complete, and the test stand is getting ready... Sub-system level tests are going on at facilities in Mahendragiri & LPSC,” he added. 7/n

#GSLVMk3 is a three-stage vehicle with two solid strap-on motors (S200), one liquid core stage (L110) and a high-thrust cryogenic upper stage (C25). While the S200 will remain the same, the SC120 will replace L110 and C25 will be upgraded. 8/n

“...We are expecting qualification to be completed in a couple of months unless some anomalies are found which may call for repeated tests, which are not unusual during the evolution stage,” Kumar said. 9/n

He added that aside from increasing the payload carrying capability, the new configuration would also make the vehicle safer as it will use non-toxic elements compared to L110. 10/n

“It'll use refined kerosene, which is like aviation fuel. This means stage handling will be very safe, there'll be an increased capacity, ground systems handling becomes much simpler, storage leakages & human aspect concerns get reduced while handling the stage,” Kumar said. 11/n

The #GSLVMk3 project was first approved in 2002, with a mandate of achieving the capability to launch a four-tonne class satellite to Geosynchronous orbit (GEO), which Isro achieved through three demonstration missions. 12/n

Then, the phase-1 of the GSLV-Mk3 continuation programme was approved in June 2018 to build 10 launch vehicles to meet the programmatic requirements to launch communication satellites up to the year 2023. 13/n

A year after this approval, the rocket, in its maiden operational flight successfully launched #Chandrayaan2 on July 22, 2019 and had its first commercial mission on October 23, 2022. It is now scheduled to launch 36 more satellites for UK-based @OneWeb in early 2023. n/n