Jul 12, 2010

PSLV-C15/CARTOSAT-2B

PSLV-C15 is the seventeenth flight of ISRO's versatile Polar Satellite Launch Vehicle, PSLV. In this flight, PSLV placed the 694 kg CARTOSAT-2B in a 630 km polar Sun Synchronous Orbit (SSO). PSLV was initially designed for launching 900 kg Indian Remote Sensing Satellites into a 900 km polar SSO.

Since its first launch in 1993, the PSLV has been successively improved to attain its present capability of launching 1750 kg into an 630 km polar SSO. The major changes made in PSLV since its first launch include the increase in the propellant loading of the first stage solid propellant motor as well as the strap-ons and the second and fourth liquid propellant stages, improvement in the performance of the third stage motor by optimising motor case and enhanced propellant loading and employing a carbon composite payload adopter.

PSLV has also been made a more versatile vehicle for launching multiple satellites in polar SSOs as well as for launching satellites into Geosynchronous Transfer Orbit (GTO) and Low Earth Orbit (LEO). With fifteen consecutively successful launches, PSLV has emerged as a workhorse launch vehicle of ISRO and is offered for launching satellites of other space agencies also. Besides launching 17 Indian satellites, PSLV has launched 22 foreign satellites as well during 1994-2009 period into polar Sun Synchronous, Geosynchronous Transfer Highly Elliptical and Low Earth Orbits and has repeatedly proved its reliability and versatility.

For PSLV-C15 mission, the 'Core Alone' version of PSLV has been chosen based on the weight of the payload and the orbit to which it is to be placed. The 44 metre tall 'Core Alone' version of PSLV weighs 230 tonne at lift-off. Six solid 'strap-on motors', clustered around the first stage of PSLV 'standard version' to enhance its thrust, are absent in 'core alone' version. PSLV-C15 is the sixth flight of the 'Core Alone' version of PSLV.

PSLV- C15 Stages at a Glance
 
STAGE-1
STAGE-2
STAGE-3
STAGE-4
Nomenclature
Core (PSI)
PS2
PS3
PS4
Propellant
Solid
HTPB Based
Liquid
UH25+N2O4
Solid HTPB
based
Liquid MMH +
MON-3
Mass (Tonne)
138
41.0
7.6
2.5
Max Thrust (kN)
4817
799
238
7.3 x 2
Burn Time (Sec)
101
147
112
497
Stage Dia (m)
2.8
2.8
2.0
2.8
Stage Length  (m)

20

12.8
3.6
2.6
Control
SITVC for Pitch & Yaw, Reaction Control Thrusters for Roll Control
Engine Gimbal for Pitch & Yaw, Hot Gas Reaction Control Motor for Roll Control
Flex Nozzle for Pitch & Yaw, PS4 RCS for Roll Control
Engine Gimbal for Pitch, Yaw and Roll, On-off RCS for Coast Phase Control.