The Polar Satellite Launch Vehicle (PSLV) is all set for its 25th mission and this time it is on a voyage to another planet – The Mars. The Vehicle will travel around 400 million kms carrying 1337 Kg of payload mass and Scientists says this journey will be more challenging for the PSLV, which concluded 23 successive successful missions accomplished, including to the Moon.
The 44.4 m long PSLV-C25, with Indian flag painted on the Nose, stands erect looking at the blue sky at the ISRO's Satish Dhawan Space Centre at Sriharikotta, some 100 kms from Chennai. The Vehicle, with payload, has went through over eight hours of test on Thursday and ISRO said it was successful.
This time, the Mission of PSLV
and 5th in the XL configuration, will carry the Mars
Orbiter Satellite (1337 kg) into a 250 km X 23500 km elliptical orbit. The Satellite will be further navigated to a hyperbolic departure technology and thereafter it traverses an interplanetary cruise trajectory before reaching the intended orbit around the Mars, according to ISRO.
The vehicle is expected to reach its destination sometime in September 2014.
Scientists are hopeful that the Vehicle will complete the journey successfully, just like the way it did in the past, including the one to Moon. List of a few successful missions of PSLV in the past.
This journey will have more challenges for PSLV, says ISRO, and the major technical challenges for the Launch Vehicle in accomplishing this Mission arise from the larger Argument of Perigee
(AOP) requirement ranging from 276.4 degree to 288.6 degree compared to 178 degree in earlier Missions.
This AOP minimises the energy required in transferring the satellite from the Earth to the Mars. In this regard, the Launch Flight regime is extended to 2657s, as against 1200s for regular PSLV missions, with a long coasting (1580-1800s) before the ignition of the PS4 stage.
ISRO stated that the long coasting necessitated specific modification and validation of the coast phase guidance algorithm, on-board battery capacity augmentation, assessment on the performance of inertial systems for extended flight duration and deployment of two ship-borne terminals to capture the crucial telemetry data during flight in the non-visbility zone.
ISRO said that additional provisions were made for the thermal management of Vehicle Equipment Bay, PS4 stage and also the Spacecraft elements considering the longer exposure to extreme cold space.
Another unique task associated with management of this Mission, according to ISRO, is the generation and Configuration Control of Multiple Initialisation files for the on-board computers corresponding to the different launch dates.
PSLV is the first operational launch vehicle of ISRO and it caters to the requirements of launching satellites into Sun-Synchoronous and Low Earth Orbits. PSLV is a four stage vehicle with alternate Solid and Liquid propulsion stages. The booster stage along with the strap-on motors and the third stage are solid motors while the second and fourth stages use liquid engines.
PSLV has the capability to launch 1750 kg class satellites into 600 km Sun-Synchronous Polar Orbit (SSPO) and 1425 kg satellites into Sub-Geosynchronous Transfer Orbit (Sub GTO) of 284 km X 21000 km. The vehicle has provision to launch multiple satellites.
PSLV has successfully accomplished two developmental and 21 operational Missions in a row and demonstrated reliability of 0.96. Currently two variants of PSLV are operational, namely PSLV-XL (with six extended strap-on motors attached to the first stage) and PSLV-Core Alone (without strap-on motors).
PSLV-C25/Mars Mission employs the PSLV-XL version which has already been used in four earlier missions.