Bangalore: In a likely indication of the eventual human spaceflight (Gaganyaan) mission profile, ISRO has finalised several aspects of mission planning for the first uncrewed mission or G1 — planned for next year — which will will see the launch vehicle inject the orbital module into a 170 X 408km orbit reports Times News Network.

The G1 mission will be followed by G2, the second uncrewed mission, both of which are precursors to the eventual human/crewed mission or H1 as named by ISRO. Just as H1, the G1 too will be launched by a Human-Rated GSLV-MK-III or the HRLV (Human-Rated Launch Vehicle).

As per ISRO: “The specification for injection parameters for HRLV during G1 has been revised from 170 X 395 to 170 X 408 kilometre in order to ensure adequate propellant margin in the service module propulsion system.”

Also, the circularisation manoeuvre — for moving from an inserted orbit to a more circular orbit — is planned in the third orbit apogee (farthest point) instead of the fourth, in order to reduce the residency period of the perigee (closest point) to a lower altitude of 170km.

ISRO said a mission interface committee is constituted to review and finalise all the data flow interfaces between participating entities or teams in the ground segment and added that different types of SNAP (separation) scenarios — various abort conditions — in the overall (including crewed) mission were identified for which different sequences of operations are worked out depending upon the separation scenario.

“Mission plans for touchdown under nominal and contingency scenarios have been worked out. The corresponding communication network availability for different options was also worked out. Mission sequence documents for the descent phase in G1 mission have been finalised for on-board implementation,” ISRO said.

The mission sequence documents for the descent phase in G1 will be similar to the TV-D1 — the special test vehicle’s (TV) first demonstration (D1) mission. After TV-D1, which is expected later this year, ISRO will also launch TV-D2 and G1 and G2 are only scheduled for 2023.

“Various touchdown locations for nominal descents, ascent phase aborts and on-orbit phase abortion have been worked out as per the latest mission plan and presented to the inter-agency committee for recovery operations (ICRO). The requirements for communication equipment on-board the recovery ships for ensuring real-time communication with the mission control centre have also been presented,” ISRO added.

With the objectives and configuration for G1 having been defined and design of the orbital module — consisting crew module and service module — complete with all fabrication drawings having been generated, ISRO has begun procurement of raw materials and realisation of sub-assemblies.

“Propulsion system configuration has been finalised and realisation is in progress. System demonstration tests for qualification of the propulsion system have been initiated and five ground tests have been completed for the module propulsion system,” ISRO said.

Also, HRLV design has been completed and hardware realisation is in the advanced stages both for stage systems and certain tests have been completed, while raw materials have been procured for a majority of the systems.

“The realisation of three sets of hardware namely for qualification tests, TV-D1 mission and G1 is taken up parallelly,” ISRO said, adding that qualification tests for the crew escape system (CES) solid motors have been initiated and static tests of two motors have been completed.