PSLV explores new heights

Journalists covering rocket launches at Sriharikota generally come with two story templates in hand — one on success and the other on failure. This is to meet the story deadline, whatever the outcome.

However, when it comes to the Polar Satellite Launch Vehicle (PSLV), the failure story always goes to the trash bin folder of their email, while the success always goes to print.

That’s how reliable the PSLV has been so far. In fact, the PSLV has rightfully earned the status of ‘workhorse’ launch vehicle of the Indian Space Research Organisation (ISRO).

PSLV’s mission is not complete. On or after October 21, its flight mission will be put to test on two things that will be critical in India’s space mission that started nearly five decades ago.

One is that PSLV will be on its silver jubilee flight, and secondly, it will carry the Mars Orbiter with it. By launching a mission to Mars, India will have joined an elite club that includes the US, Russia, Europe, Japan and China.

Referring to the launch of PSLV-C22 from Sriharikota during the night of July 1, ISRO’s Chairman, K. Radhakrishnan, said: “I am extremely happy to announce that we had another excellent flight of our PSLV vehicle. This is the 23rd successive successful flight of PSLV and the fourth successful flight of extended version of PSLV.”

“It was a precise launch,” he said. “This only proves that PSLV is an extremely reliable vehicle and with this flight, we are also entering into a new era of space application in the country — that is the beginning of satellite navigation programme.”.

Stepping stone to success

The success of the PSLV, in fact, started with a disaster. On October 20, 1993, the first PSLV-D1 launch failed due to a software guidance error. All the systems of PSLV-D1 had performed creditably.

However, the vehicle failed to inject the IRS-1E satellite into the intended polar orbit. The launch vehicle plunged into the Bay of Bengal, just 700 seconds after lift-off from Sriharikota.

And, here the two-template strategy of journalists did help. In fact, one journalist immediately after the lift-off flashed that the launch was a success, only to reverse the copy afterward.

Scientists at ISRO learnt from the mistakes and worked on the second developmental flight PSLV-D2, which flawlessly deployed the IRS-P2 into polar sun-synchronous orbit at a height of 825 km.

There was no looking back from the second mission and PSLV’s reliability so far has been superb. With its variant configurations, PSLV has proved its multi-pay load, multi-mission capability in a single launch and its geosynchronous launch capability, said an official of ISRO.

In the recent PSLV-C22 flight, which cost around Rs 135 crore, the XL version of PSLV was used. This version carries six large strap-on motors, each carrying 12 tonnes of solid propellants. Compared with this, the standard version has six strap-ons, each carrying 9 tonnes of solid propellants.

In fact, PSLV C-22 was the fourth flight of XL version of PSLV. Earlier, PSLV-XL had successfully launched Chandrayaan-1, GSAT-12 and RISAT-1 spacecraft into orbit.

Self-reliance

For long, India was relying on the erstwhile Soviet Union for space launches. However, the launch of PSLV-D1 marked the country’s march towards self-reliance in the complex launch vehicle technology.

Its development took nearly ten years in the three launch centres of ISRO — Vikram Sarabhai Space Centre and Liquid Propulsion System Centre (both in Thiruvananthapuram, Kerala) and Satish Dhawan Space Centre SHAR, Sriharikota, 90 km north off Chennai, in Andhra Pradesh.

The ‘workhorse’ was designed to place 1,000 kg class Indian Remote Sensing satellite into a 900 km orbit. After the successful flight in October 1994, its capability was significantly enhanced.

The improvement included increased propellant loading and strap-on motors, employing composite material for the satellite mounting structure and changing the sequence of firing of the strap-on motors.

Today, PSLV is capable of launching 1,600 kg satellites in 620 km sun-synchronous polar orbit and 1,050 kg satellite in geo-synchronous transfer orbit. PSLV’s success has prompted many countries to launch their satellites through ISRO’s ‘workhorse.’

In fact, PSLV has so far launched 35 satellites for international customers and has established ISRO as a major player in the satellite launching business.

PSLV-C21 launched French satellite SPOT- 6 and Japanese satellite PROTIERS on September 9, 2012.

In February, the PSLV-C20 launched six foreign satellites into orbit along with the Indo-French satellite SARAL.

Silver jubilee flight

The stage is now set for the PSLV’s silver jubilee flight with Mars Orbiter towards October end, as Mars is closest to Earth in November.

The mission’s technological objective is to design a spacecraft capable of reaching Mars (Martian Transfer Trajectory) and orbiting the planet (Mars Orbit Insertion). This will take around nine months.

Another technological challenge is to realise related deep space mission planning and communication management at a distance of nearly 400 million km.

The US space agency NASA will provide deep space navigation and tracking support services for this mission during the non-visible period of the Indian Deep Space Network. ISRO will start stacking the launch vehicle from July 29.

The Orbiter is getting ready at Bangalore and should be in Sriharikota by September.

It will be launched by the PSLV XL launch vehicle after which its apogee (the farthest point from earth) will be increased from 20,000 km to two lakh km before it begins its voyage to Mars around November 28 or 29, said Radhakrishnan, who seeks the blessings of Tirumala deity Balaji before every rocket launch.