SRIHARIKOTA: INDIA’S workhorse Polar Satellite Launch Vehicle (PSLV) regained its ‘sky’ worthiness on Friday successfully placing 31 satellites in two different orbits in one mission. This was one of the keenly followed missions in the aftermath of an expected failure experienced in August last year.
Blasting off from the first launch pad of Satish Dhawan Space Centre in Sriharikota, about 100 km from Chennai, the 44.4-metre-tall PSLV-C40 roared into upper atmosphere with a lift-off mass of 320 tonnes as majestically as ever.
There was a loud applause in the control room when PSLV was 2 minutes and 31 seconds into the flight as the payload fairing or heat shield separation was declared successful. The previous launch had failed primarily because heat shield separation did not take place and as a result, the satellite got trapped inside the heat shield. The launch was a litmus test for the PSLV in terms of reliability and robustness. Though the PSLV has seamlessly carried out 39 consecutive successfully launches, the last failure has thrown up several questions over the technology being used. In this context, the Indian Space Research Organisation (ISRO) has taken a four-month interval to revisit some of the core areas.
Around 17 minutes into the flight, the PSLV injected its main payload 710-kg Cartosat-2, the seventh satellite in the series, into a polar sun-synchronous orbit at an altitude of about 510 km. In seven minutes, the rocket lobbed 29 satellites in a predefined sequence. Cartosat-2, which is a remote sensing satellite, is intended to augment data services to the users.
Mission director R Hutton confirmed that the satellite was brought to operational configuration, following which it began providing regular remote sensing services using its panchromatic and multi-spectral cameras. “It’s an excellent mission and a good start for 2018. Cartosat-2 is our new year gift to the nation. Cartosat’s performance has been so far satisfactory,” said retiring ISRO chairman A S Kiran Kumar.
The imagery sent by the Cartosat-2 series satellite will be useful for cartographic applications, urban and rural applications, coastal land use and regulation, utility management like road network monitoring, water distribution, creation of land use maps, change detection to bring out geographical and manmade features and various other Land Information System as well as Geographical Information System applications.
P Kunhikrishnan, director, Satish Dhawan Space Centre, said the mission was an excellent and befitting tribute to Kiran Kumar and a welcome to chairman-designate K Sivan under whose leadership the agency looks to scale new heights.
Multi-burn tech mastered
The ISRO has mastered the ‘money-spinning’ multi-burn technology with this launch.
After the ejection of the 30th satellite, the fourth stage of the rocket was re-ignited twice to bring down the altitude from 510 km to 359 km. The engine was first re-started 58 minutes into the flight and shut down after five seconds and again restarted 1 hour 44 minutes into the flight. The last satellite Microsat, which weighs 130 kg, was ejected a minute later. In total, the mission continued for two hours, 21 minutes and 62 seconds, making it one of the longest.
“This shows PSLV can deliver multiple satellites into single orbit and satellites into multiple orbits providing distinctive advantage over other commercial launches vehicles... We are very quick and receptive towards our customer needs. For example, in February last year, we never thought we would launch 104 satellites in one go. The plan was for 80 satellites, but we did quick analysis and accommodated 104. For small satellites customers, such opportunities don’t come easy and they have to wait for months,” Kiran Kumar said.
Hutton said all vehicle systems performed remarkably. This shows the problems encountered in previous launch have been identified and fixed. ISRO officials said a robust review process had been carried out, based on the data obtained from telemetry. “Teams have identified what exactly has happened and analysed how it would have happened and carry out simulations to recreate the scenarios and overcome the challenges. Design, flight readiness and mission readiness have been reviewed,” Kiran Kumar said, without specifying the exact modifications made to the rocketry. “If you don’t fail, that means you are not pushing yourself to do greater things. The rocket technology is the most complex, which is why it is seen as a risky business,” he said.
Busy 2018 ahead
Chairman-designate K Sivan said the success of PSLV-C40 meant green flag for all high-profile launches in 2018 calendar year, which includes Chandrayaan-2. “We plan to have one launch each month,” he said.
P Kunhikrishnan, director, Satish Dhawan Space Centre, said the launch campaign for GSLV Mk2, which will carry one of the communication satellites, has begun in the second launch pad. The launch is scheduled for next month. “We are planning three consecutive launches from second launch pad.”
Besides, there are several big ticket infrastructure project nearly completion at Sriharikota that would propel the ISRO capabilities.
Mission followed an expected failure suffered in Aug last year
Foreign customer satellites
Republic of Korea: 5
ISRO recovers cost
ISRO has recovered 60% of cost incurred on the launch by foreign customers
The combined weight of 28 foreign satellites is 470 kg and the Indian payload weighed about 900 kg
Foray into small satellites segment
The launch marked the ISRO’s foray into small satellite market. For the first time, the ISRO has built a microsatellite in the 100-kg class that derives its heritage from IMS-1 bus and has flown in as co-passenger. An Indian Nano Satellite-1C, weighing just 11 kg, was also built by ISRO as a technology demonstrator. Tapan Misra, director, Space Applications Centre, told Express that his team had taken up the challenge to indigenise and miniaturise the systems