ISRO scores a 100, PSLV takes the cake with most trips to space

Sriharikota (Andhra Pradesh): The Indian Space Research Organisation (ISRO) on Wednesday achieved a historic milestone with its 100th mission and revealed an ambitious future plan of crossing the next 100 launches in five years.

Starting off with the SLV in 1979, the space agency crossed the 100-mission mark after 46 years, but what stands out is the PSLV's dominance through the years with 62 missions.

The Polar Satellite Launch Vehicle (PSLV) has turned out to be ISRO's most trusted rocket, thanks to its unmatched reliability.

While PSLV has been used for 62 missions, GSLV with indigenous cryogenic upper stage comes next with 17. LVM3 (Geosynchronous Satellite Launch Vehicle MkIII--the heaviest rocket) with 7 and SSLV (Small Satellite Launch Vehicle) 3, follow suit.

The others are Reusable Launch Vehicle, TV (Test Vehicle) and PAT (Pad Abort Test).

PSLV, often dubbed as the "trusted workhorse of ISRO" by scientists, has been used consistently to inject various satellites into precise Low Earth Orbits. The vehicle which is 44.4 metre tall is equipped to take payloads of up to 1,750 kg to Sun-Synchronous Polar Orbits of 600 km altitude.

However, on account of its unmatched reliability, ISRO said PSLV was also used to launch various satellites into Geosynchronous and Geostationary orbits, like satellites from the IRNSS constellation.

The PSLV comes in four variants -- PSLV-CA, PSLV-DL, PSLV-QL, PSLV-XL.

The first launch of PSLV was PSLV-D1 launched on September 20, 1993. It was an unsuccessful attempt. However, the rocket made its first successful launch in October 1994 and later emerged as the most reliable and versatile launch vehicle of ISRO.

Some of the significant missions that were successfully launched by PSLV include the ambitious Chandrayaan-1 in 2008 and Mars Orbiter Spacecraft in 2013. Scientists describe the Chandrayaan-1 and Mars Orbiter Mission as the 'feathers in the hat' of PSLV.

The Sriharikota spaceport situated about 135 km east of Chennai has two launch pads and incidentally the first launch pad came into service from September 1993 by launching a PSLV/IRS-P1 mission. The second launch pad also commenced operations, from May 2005 with the launch of PSLV-Cartosat-1, ISRO officials said.

GSLV, has given ISRO a run for its money, thanks to the challenging technology behind the rocket.

So much so, some repeated failures prompted GSLV to be called 'naughty boy,' but things have since changed.

However, the flawless weather observation satellite INSAT-3DS mission last year prompted the ISRO to virtually heave a sigh of relief over the challenging GSLV rocket technology, with one of the scientists quipping the "naughty boy has matured into an obedient, disciplined boy."