Jason DavisJan 06, 2014

India keeps up the momentum, returning troubled GSLV to flight

It’s been an exciting two months for India’s space program. 

On Nov. 5, the country launched its first Mars-bound spacecraft, the Mars Orbiter Mission, into orbit. MOM took a few, long orbit-raising laps around the Earth before conducting a long engine burn to send it into interplanetary space. It is now speeding towards a Sept. 2014 Martian rendezvous. The mission puts India in a small, elite group of nations that have attempted a planetary spacecraft journey.

Two months later to the day on Sunday, the India Space Research Organisation watched with nervous excitement as their largest, most troubled rocket, the Geosynchronous Satellite Launch Vehicle, sat on the launch pad at Sriharikota. 

“We will have ignition of the four liquid strap-ons at minus 4.8 seconds,” said a launch commentator. “After confirming the performance of the liquid strap-ons, the command for the ignition of the S-139 solid motor will be at T-zero.”

Another voice began the final countdown: “Ten, nine, eight ...”

“L-40s have ignited,” said the commentator, as the boosters roared to life. The clock hit zero, the S-139 lit and GSLV-D5 leapt from the pad.

“Vehicle liftoff! Vehicle liftoff!” said the commentator. Hindi and English voices on the audio feed overlapped. Above the din, as the rocket rose, the commentator said the vehicle was “going majestically through the atmosphere.”

Liftoff was an important milestone, but the most critical part of the flight was yet to come. In five minutes, the GSLV’s second stage would separate and the third stage cryogenic engine would come to life. Built proudly in India, the engine failed during its first outing, and the GSLV had been plagued with setbacks ever since.  

GSLV-D5 lifts off
GSLV-D5 lifts off India's GSLV-D5 rocket lifts off on Jan. 5, 2014, carrying a communications satellite to geostationary transfer orbit. The mission marks the first successful flight of ISRO's Cryogenic Upper Stage.Image: ISRO

The GSLV can haul two-and-a-half tons to geosynchronous transfer orbit. That gives it double the payload capacity of the PSLV, the Polar Satellite Launch Vehicle, which sent MOM on its way to Mars in November. 

I wrote about the GSLV’s troubles back in July. The story goes like this: the rocket debuted in 2001. India initially wanted Russia to show them how to build a third stage cryogenic engine, but the West intervened. The official reason? Concern that India could use the technology for military purposes. There were also likely economic reasons—other countries, including Russia, had an incentive to keep the list of available satellite launchers small

Instead, Russia agreed to sell India some engines directly off-the-shelf. In the meantime, the ISRO pressed ahead with developing a third stage engine on their own, and debuted the result—the Cryogenic Upper Stage, or CUS—in April 2010. During the flight of GSLV-D3, the CUS came to life as planned, but the outing was short-lived. A turbopump failed, starving the engine of liquid hydrogen. The engine died after just two seconds, and the rocket tumbled to a watery demise in the Bay of Bengal. 

GSLV-D5 Indigenous Cryogenic Upper Stage
GSLV-D5 Indigenous Cryogenic Upper Stage The GSLV-D5's Cryogenic Upper Stage (CUS) is integrated with the rocket's second stage.Image: ISRO

As its engineers investigated the CUS failure, the ISRO pressed on with another GSLV launch eight months later using a Russian engine. The result was no better. A group of electrical pins snapped at the bottom of the third stage. The rocket lost control and sheared apart. India had back-to-back GSLV failures on its hands, and the rocket’s overall success rate was four out of seven. 

Many Indian media outlets lamented the failures as a blow to national pride. The question of pride, competition with China and the place of a space program in a nation with crushing poverty is interesting—Emily recently touched on this in a Mars Orbiter Mission article. Regardless, the ISRO made changes to their beleaguered rocket and homebrew upper stage, rolling GSLV-D5 out to the launch pad in July 2013. 

This time, it was the second stage that misbehaved. Three-quarters of a ton of fuel inexplicably leaked out onto the launch pad, scrubbing the launch. According to an ISRO statement, it took six days of around-the-clock cleanup before the rocket could be moved back to the Vehicle Assembly Building for de-stacking. The second stage was swapped out entirely. All four liquid boosters were replaced. And on the morning of Dec. 28, GSLV-D5 was rolled out to the launch pad once again—this time, for a Jan. 5 launch. 

As GSLV-D5 streaked upward with everything going to plan, the nail-biting moment of truth arrived. 

“Second stage has been separated,” called out a voice on the launch webcast. More Hindi and English voices overlapped, and in mission control, technicians and engineers were seen applauding—cautiously, at first. 

“Ignition sustained!” cried the launch commentator. “The vehicle is going through its altitude profile and the velocity profile as planned!” It was smooth sailing from there, with the Cryogenic Upper Stage burning for about 12 minutes. It released its payload, communications satellite GSAT-14, into geosynchronous transfer orbit. ISRO’s Master Control Facility at Hassan will command the satellite to conduct a series of burns to circularize its orbit, placing it into operation at 74 degrees East longitude. 

The events of the past two months have raised India’s space program’s stature. During that time, the ISRO increased its social media presence to match. After quelling some confusion about a handful of unofficial Facebook and Twitter fan pages, the space agency finally joined Twitter. After the launch of GSLV-D5, @ISROOFFICIAL posted a slew of charming tweets, calling the troubled rocket a “naughty boy” and hailing its flight as a “victory over gravitation.”

Prior to launch, the ISRO also released an eight-minute video montage of the GSLV-D5 being assembled. Not only does the video offer a nice look at how a launch vehicle is put together, it’s refreshingly candid, showing the expressions of dedicated ISRO workers as they prepare their “naughty boy” for flight. When the guy at 6:30 watching the solar array deployment test starts clapping, you may find yourself clapping with him.

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