PSLV C23: Civil Services Mentor Magazine - August 2014

PSLV C23

Primary Satellite (Free Available)
Co-passenger Satellites (Free Available)
HISTORY OF PSLV (Free Available)
Typical Parameters of PSLV (Only for Online Coaching Members)
PSLV Milestones (Only for Online Coaching Members)
PSLV “global endorsement of India’s space capability” (Only for Online Coaching Members)

India on 30th June, 2014, successfully launched five foreign satellites from four countries on board PSLV C 23 rocket which placed them in orbit, an achievement described by Prime Minister Narendra Modi as an ‘endorsement’ of the country’s space capabilities. After a perfect lift off from the First Launch Pad in Satish Dhawan Space Centre here at 9.52 AM, Indian Space Research Organisation’s workhorse Polar Satellite Launch Vehicle PSLV-C23 placed all five satellites into their intended orbits, one after the other between 17 and 19 minutes after liftoff, in textbook precision.

The PSLV-C23 carried a 714 kg French Earth Observation Satellite SPOT-7 as its main payload while a 14 kg satellite called AISAT of Germany, two 15 kg satellites from Canada CAN-X4 and CAN-X5 and seven kg Singapore satellite called VELOX-1 as piggy back payload on the flight.

Primary Satellite

SPOT-7: It is a French earth observation satellite and identical to SPOT-6 launched earlier on-board PSLV C21 during September 2012. It will be launched into a 655km Sun Synchronous Orbit (SSO) will be phased and placed diametrically opposite to SPOT-6 and will form part of the existing earth observation constellation. Satellite mass is 714 Kg with a mission life of 10 years, build by Airbus Defence & Space.

Co-passenger Satellites

AISAT: It is a global sea traffic monitoring satellite with special emphasis on high traffic zones using AIR signals. Satellite mass is 14 kg, build by DLR Germany.

NLS 7.1 & NLS 7.2: It is a two-spacecraft precision formation flying using different GPS with cm-level relative position and sub-metre level accurate position control system. Satellite mass is 15 kg each, build by UTIAS/SFL Canada.

VELOX-1: It is a technology demonstrator for in-house design of image sensor, MEMS-based attitude determination and control system, inter-satellite RF-link.

The five satellites were launched under commercial arrangements that ANTRIX (ISRO’s commercial arm) entered with the respective foreign agencies.

MON-3: Mixed Oxides of Nitrogen·

SITVC: Secondary Injection Thrust Vector Control

Till April 2014, there had been 25 consecutive successful flights of PSLV and this is the 26th such launch. Meanwhile, PSLV-C23 is the 10th flight of PSLV in ‘core-alone’ configuration, which means a configuration without the use of solid strap-on motors.

After an estimated time of 20 minutes, Isro’s workhorse PSLV separated all five satellites — one by one into their intended orbit. All the satellites were separated as planned, Isro said in a statement.

SPOT-7 is a French optical earth observation satellite identical to SPOT-6 launched earlier on-board PSLV-C21 in September 2012. SPOT-7, after its injection into the SSO, will be phased and placed diametrically opposite to SPOT-6 and will form part of the existing earth observation constellation.

The commercial launch comes nearly 16 months after ISRO launched six small foreign satellites on board the PSLV C-20 in February 2013. There had been 26 continuously successful flights of PSLV, till June 2014. PSLV has repeatedly proved its reliability and versatility by launching 70 satellites / spacecrafts (30 Indian and 40 Foreign Satellites) into a variety of orbits so far. Some notable payloads launched by PSLV include India’s Chandrayaan-1 lunar probe and the Mars Orbiter Mission.

Launch Vehicles are used to transport and put satellites or spacecrafts into space. In India, the launch vehicles development programme began in the early 1970s. The first experimental Satellite Launch Vehicle (SLV-3) was developed in 1980. An Augmented version of this, ASLV, was launched successfully in 1992. India has made tremendous strides in launch vehicle technology to achieve self-reliance in satellite launch vehicle programme with the operationalisation of Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV).

Vehicle description

The PSLV has four stages using solid and liquid propulsion systems alternately. The first stage is one of the largest solid-fuel rocket boosters in the world and carries 138 tonnes of Hydroxyl-terminated polybutadiene (HTPB) bound propellant with a diameter of 2.8 m. The motor case is made of maraging steel. The booster develops a maximum thrust of about 4,430 kN. Six strap-on motors, four of which are ignited on the ground, augment the first stage thrust. Each of these solid propellant strap-on motors carries nine tonnes of HTPB propellant and produces 677 kN thrust. Pitch and yaw control of the PSLV during the thrust phase of the solid motor is achieved by injection of an aqueous solution of strontium perchlorate in the nozzle to constitute Secondary Injection Thrust Vector Control System (SITVC). The injection is stored in two cylindrical aluminum tanks strapped to the solid rocket motor and pressurized with nitrogen. There are two additional small liquid engine control power plants in the first stage, the Roll Control Thrusters (RCT), fixed radially opposite one on each side, between the triplet set of strap-on boosters. RCT is used for roll control during the first stage and the SITVC in two strap-on motors is for roll control augmentation.

The second stage employs the Vikas engine and carries 41.5 tonnes (40 tonnes till C-5 mission) of liquid propellant– Unsymmetrical Di-Methyl Hydrazine (UDMH) as fuel and Nitrogen tetroxide (N2O4) as oxidizer. It generates a maximum thrust of 800 kN (724 till C-5 mission). Pitch & yaw control is obtained by hydraulically gimbaled engine (±4°) and two hot gas reaction control for roll.

The third stage uses 7 tonnes of HTPB-based solid propellant and produces a maximum thrust of 324 kN. It has a Kevlar-polyamide fiber case and a submerged nozzle equipped with a flex-bearing-seal gimbaled nozzle (±2°) thrust-vector engine for pitch & yaw control. For roll control it uses the RCS (Reaction Control System) fourth stage.

The fourth and the terminal stage of PSLV has a twin engine configuration using liquid propellant. With a propellant loading of 2 tonnes (Mono-Methyl Hydrazine as fuel + Mixed Oxides of Nitrogen as oxidiser), each of these engines generates a maximum thrust of 7.4 kN. Engine is gimbaled (±3°) for pitch, yaw & roll control and for control during the coast uses on-off RCS. PSLV-C4 used a new lightweight carbon composite payload adapter to enable a greater GTO payload capability

HISTORY OF PSLV

The Polar Satellite Launch Vehicle,usually known by its abbreviation PSLV is the first operational launch vehicle of ISRO. PSLV is capable of launching 1600 kg satellites in 620 km sun-synchronous polar orbit and 1050 kg satellite in geo-synchronous transfer orbit. In the standard configuration, it measures 44.4 m tall, with a lift off weight of 295 tonnes. PSLV has four stages using solid and liquid propulsion systems alternately. The first stage is one of the largest solid propellant boosters in the world and carries 139 tonnes of propellant. A cluster of six strap-ons attached to the first stage motor, four of which are ignited on the ground and two are air-lit.
The reliability rate of PSLV has been superb. There had been 26 continuously successful flights of PSLV, till June 2014. With its variant configurations, PSLV has proved its multi-payload, multi-mission capability in a single launch and its geosynchronous launch capability. In the Chandrayaan-mission, another variant of PSLV with an extended version of strap-on motors, PSOM-XL, the payload haul was enhanced to 1750 kg in 620 km SSPO. PSLV has rightfully earned the status of workhorse launch vehicle of ISRO. PSLV has repeatedly proved its reliability and versatility by launching 70 satellites / spacecrafts ( 30 Indian and 40 Foreign Satellites) into a variety of orbits so far.