The countdown for the launch of Isro’s advanced weather satellite INSAT-3DR onboard GSLV-F05 began on Wednesday at 11.10 am.
"The 29-hr countdown operation of GSLV-F05/INSAT-3DR Mission has started at 11.10 hrs on 7 September," Isro said.
GSLV is a three-stage launch vehicle
According to a report in The Times of India, GSLV is a three-stage launch vehicle and a cryogenic engine is used in the third or upper stage. INSAT-3DR is an advanced weather satellite which weighs around 2,211 kg.
The cryogenic engines use liquid hydrogen as fuel and liquid oxygen as oxidiser to burn the fuel. It can produce 1.5 times the thrust compared to liquid rocket engines.
Launch to take place from Sriharikota
The rocket will be launched on 8 September at 4.10 pm from the second launchpad at Satish Dhawan Space Centre SHAR (SDSC SHAR), in Sriharikota, PTI reported. The launch was earlier scheduled on 28 August.
Thursday’s launch will be the first time an indigenous cryogenic engine will be used on an operational flight.
Operational flight is one when components are not tested
According to a report in The Wire, an "operational flight means Isro will not be testing any components, flight parameters or flight routes. The launch will solely be about the mission: delivering the payload." This launch will be a "litmus test" for India's home-made cryogenic technology.
Speaking to The Times of India, a Isro scientist said, "When we build a new rocket, we do a developmental flight to ascertain if it will work properly. Once we are confident, we call it an operational flight which will be considered a routine launch. GSLV-F05 will place the satellite in the geostationary transfer orbit from where the satellite with its propellant will raise to its final geostationary orbit."
The need to develop indigenous cryogenic engines arose because these engines are necessary to put satellites in geostationary orbit and all Russia-supplied engines were already used. Isro, therefore, had to develop a material which could withstand high temperature and pressure.
Indigenous engine had three development flights
Before declaring Thursday’s launch, the indigenous engine had three development flights. Thursday will be the first operational flight.
Earlier with similar configurations, GSLV flight successfully launched D5 and D6 missions in January 2014 and August 2015, putting GSAT-14 and GSAT-6 satellites in the intended GTOs 'very accurately'.
However, reports said that the maiden developmental flight of the indigenous engine conducted on 15 April, 2010 did not succeed.
Mission life of INSAT-3DR is 10 years
The mission life of INSAT-3DR is 10 years and it is expected to join the operational search and rescue service provided by INSAT-3D to various users, including Coast Guard, Airport Authority of India, Shipping and Defence Services.
It will also provide a variety of meteorological services to the country. According to The Wire, it is also expected to continue the mission of the INSAT-3D satellite, which was launched in 2013.
Launch will be the tenth GSLV flight
GSLV-F05 would be the tenth GSLV flight. "GSLV-F05 is the flight in which the indigenously developed Cryogenic Upper Stage is being carried on-board for the fourth time during a GSLV flight," reported The Business Standard.
GSLV is of three kinds
GSLV is of three kinds: Mk-I, Mk-II and Mk-III. The MK-I uses Russian engines for the third stage. "The Mk-II uses four liquid-fuel strap-on boosters in addition to the first stage and the CE-7.5 indigenous cryogenic engine for the third. The Mk-III will use two solid-fuel boosters for the first stage and the CE-20 indigenous cryogenic engine for the third."
The first development flight of Mk-III is expected to happen in December 2016, according to reports. Once the launch on Thursday is successful, Isro will be more hopeful about the launch of CE-20.
With inputs from PTI