GSLV Vehicle Stages

GSLV-D6/GSAT-6 MISSION

The third developmental fl ight of GSLV (GSLV-D6) with indigenous Cryogenic stage will place GSAT-6 Satellite into a Geosynchronous Transfer Orbit. The launch vehicle confi guration is similar to GSLV-D5.

Vehicle Height 49.1 m

Lift-off mass 415.712 t

Stages 3

First Stage (GS1) 4L40H+S139

Second Stage (GS2) L37.5H

Third Stage (GS3) CUS 12 (Indigenous)

GSLV-D6 Vehicle Characteristics

VEHICLE CONFIGURATION(4L40H+S139)+L37.5+

CUS12+3.4 m PLF

• Aerodynamic jet on data is used for mission design which resulted in modifi cations in DAP design to improve stability margin.

• CUS engine uprating to 11% (9.5% in GSLV-D5).

• ITT region modifi cation to reduce aerody-namic projection and mass.

• Improvements are made in Stage Processing Systems (SPS) of Lower stage & CUS.

• Two RGPD (Digital RGP) located in the same plane of RGP in IS 1/2 M to evaluate the performance in GSLV fl ight environment for introduction in the func-tional chain in future fl ights as done for PSLV.

• SCUBI (Bus Based Serial Checkout Interface) is introduced as in PSLV, in place of SCOUT for command redundancy.

Improvements/Modifications in GSLV-D6

Indigenous Cryogenic Upper Stage (CUS 12) of GSLV-D6

Indigenously developed and realized Cryogenic Upper Stage (CUS 12), designated as CUS-06, is the third stage of GSLV-D6. It is dimensionally and functionally identical to the CUS-05 stage fl own in GSLV-D5. However certain improve-ments are incorporated in CUS-06 fl ight stage and all the changes are validated. Flight systems are realized and acceptance tested.

Stage Parameters

Overall length 8.72 mOverall diameter 2.8 mStage dry mass 2490.8 kgStage mass at Lift-off 15324 kg

• Stage re-engineering in Inter Tank Truss (ITT) region:

The area between LH2 tank Aft End dome and LOX tank Fore End dome called as ITT region is re-engineered resulting in mass saving of ~ 8 kg.

• Heat shield coating material changed from PMC-30 to SSF-P70.

• Stage antistatic coating material changed from BCC-50 to GCC-50.

Design improvements in CUS-06 flight stage systems

Inter Tank Truss (ITT)

GSAT-6 is the twenty fi fth geostationary communication satellite of India built by ISRO. This satellite is intended to serve high power S-band communication applications within the Indian mainland for strategic purpose through multi beam coverage facility. This satellite is confi gured around the standard I-2K platform with minor modifi ca-tions to meet the project re-quirements with a power gen-eration capability of around 3.1 kW.

GSAT-6 payload is confi gured to provide C x S and S x C transponders.

GSAT-6

Orbital Position 83º E LongitudeSatellite Coverage Area Indian Mainland Dry Mass : 985 kg Lift-off Mass : 2117 kgPower generation Around 3.1 kWMission Life 9 yearsAntennae 6 m S-band Unfurlable antenna; 0.8 m C-band Prime-focal fi xed antennae

GSAT-6 Stowed configuration

Satellite Overview

Mass

One of the advance features of the GSAT-6 satellite is its S-Band Unfurlable Antenna of 6 m aperture diameter. This is the largest satellite antenna realised by ISRO. This antenna is utilized for fi ve spot beams over the Indian mainland. The spot beams exploit the frequency reuse scheme to increase frequency spectrum utilization effi ciency. The other advance feature of the satellite is the 70V bus, which is fl ying fi rst time in an Indian Communication Satellite.

GSAT-6 Unfurlable Antenna

GSLV-D6 Flight Sequence

Flight EventsEvents Time Altitude Relative Inertial

(s) (km) velocity velocity (m/s) (m/s)

4L40H Ignition -4.8 0.03 0 451.9

S139 Ignition 0.0 0.03 0 451.9

4L40H Shut off 148.98 70.72 2392.3 2815.9

GS2 Ignition 149.58 71.17 2393.1 2817.0

GS1 Separation 151.18 72.37 2391.6 2816.1

IS 1/2M Separation 156.98 76.58 2444.9 2871.8

PLF Separation 230.16 115.46 3448.8 3891.8

GS2 Shut off 289.28 131.75 4908.6 5354.1

GS2 Separation 292.80 132.41 4926.1 5371.7

CUS Ignition 293.80 132.58 4925.8 5371.3

CUS Shut off 1010.44 204.39 9779.0 10227.9

CUS Burn out 1012.80 206.02 9787.0 10235.9

GSAT-6 Separation 1025.44 215.35 9778.3 10227.5

For complete coverage of fl ight, Ground stations located at SHAR, Port Blair, Brunei, Biak and Singapore are used.

Vehicle Tracking and Ground Stations

SHAR

PORT BLAIR

Countdown

Operations Countdown Time (Hrs) T-Minus

Countdown starts at T-29:00:00 Hrs.

N2O4 Loading in GS2 T-28:30:00

UH25 Loading in GS2 T-24:00:00

UH25 Loading in L40s T-21:00:00

N2O4 Loading in L40s T-16:00:00

RESINS ‘ON’ T-8:30:00

Chilling and Filling of LOX in Cryostage T-4:36:00

RGPD Performance checks T-4:00:00

Vehicle internal checks T-3:00:00

Charging of CUS bottles T-2:28:00

Chilling and fi lling of LH2 in Cryostage T-2:19:00

RESINS FR Update T-1:45:00

CUS engine Chilling T-1:15:00

RESINS ground alignment T-0:27:00

VED’s Authorization for start of ALS T-0:14:00

Initiation of ALS Programme T-0:12:00

OBC fl ight reset T-0:03:30

L40s Ignition command T-0:00:4.8

Ignition of S139; LIFT-OFF T0

Glimpses of Launch Campaign

NES+CBS Stacking GS1 Segment Assembly

L40 StageAssembly

IS 1/2 V Assembly

CUS Assembly Satellite TestingGS2 Assembly

Encapsulated Assembly Vehicle Movementto UT

Fully AssembledVehicle at VAB

Published by: Documentation and Information Services-LV ProjectsVSSC, Thiruvananthapuram

Printed at : St. Joseph’s Press, Tvpm, sjptvm@gmail.com