Image: Pallava Bagla / Corbis
For the first time, Isro has built its Mars spacecraft with autonomy, so that it can operate on its own when instructions from the ground station reach it late
From the feasibility study of June 2011, which said that Isro’s most tested launch vehicle, the Polar Satellite Launch Vehicle (PSLV), could be used for a mission to Mars, to the early hours of December 1, when the spacecraft was injected into its Mars transfer orbit, it’s been an exciting journey.
If the mission could be broken into three steps, then I’d say we’ve passed the first two—getting it into earth orbit, then the injection into a planned orbit around the Sun—and are now ready for the third, on September 24, 2014: Reducing the orbiter’s velocity significantly for its entry into the Mars orbit.
With the remote sensing and geostationary missions which Isro has been performing for the past two decades, if you missed an operation you could do it in the next orbit. The Mars mission, however, is unique: Miss one operation and the spacecraft could drift off anywhere.
We have tried many new things in this mission. We use a liquid fuel engine. After the initial use of the engine—enhancing the apogee, the farthest point in the satellite’s orbit from the centre of the earth—it hibernates for nearly 300 days and is then reactivated; the fluid and pressurisations system have to survive 300 days in outer space.
Then, this mission poses a new challenge: Communication delay. Chandrayaan travelled a distance of 400,000 km; Mangalyaan will travel 1700 times that, all of 680 million km. As it gets further from earth, the one-way communication delay grows to 20 minutes. We’ve built autonomy into the spacecraft; it is able to do operations during that lag. This is the first time we’ve built a spacecraft with autonomy and if it works well, we could use in it our regular satellites, converting them into ‘smart’ satellites. That could mean a future remote-sensing satellite that could look for hot spots and steer itself to take more observations of any object of interest.
We plan for every possible contingency and build in redundancies. In other missions, these systems and components were activated by ground commands. Mangalyaan’s new fault detection and reconfiguration systems can do it on their own.
If problems come up in a near-earth spacecraft, we send it into ‘safe’ mode from our ground stations. But Mangalyaan can get into safe mode by itself, turning its antennae towards the earth, to receive commands, and its solar panels towards the sun, for energy.
A series of commands are stored in the craft’s tele-command processor which activate its five instruments or payloads. But in case we require a new sequence of operations, there’s scope for that as well. During the orbit-raising period, we have tested all these technologies and systems. So far the mission is going as per our plan. The issue is not the fuel or the three planned trajectory-correction manoeuvres—in April, August, September 2014—but the health of the satellite and of the electronics onboard. Anything can happen anytime.
We’ve taken instruments that were made in India; no instrument was left behind for want of space. Can these instruments be tweaked to get more or varied information, as ongoing missions, like Nasa’s Curiosity Rover, can? No, the capabilities are fixed. But what can certainly be tweaked is where they make observations and how many more of those they make.
That doesn’t mean we have compromised anything on scientific measurements. A Mars mission opportunity comes only every 26 months. We chose 2013 as we did not want to wait for 2016 or 2018. With our learning from this, we can always send a larger mission next time.
This has been a good year for us and we are already seeing the benefits, including in India’s private sector participation. For the first time, the Shipping Corporation of India participated, almost in mission mode. This will boost the morale of industry, which will see value addition by participating in India’s space programmes. The commercial market has shown confidence in PSLV, which can do versatile launches. We have a French and a German satellite launch commissioned on PSLV and three UK satellites of 350-kg each will be launched using this rocket.
After the successful completion of the mission in September 2014, the deep space network at Bylalu, near Bangalore, which has been enhanced for this mission, will also find its place in the global deep space network facilities (where Nasa dominates today with three networks in Goldstone, Canberra and Madrid).
We did not take this mission to win any global race—though it’s true that with the spacecraft leaving earth orbit, the world now believes that there can be a low-cost way of doing things—we wanted to compete with ourselves.
I think such missions also inspire the younger generation. In 2006, Isro received 24,000 applications for 268 positions. In 2009, post Chandrayaan-1, we received 140,000 applications for 371 seats. In 2012, we received 120,000 applications for just 22 posts!
(As told to Seema Singh)
Illustration: Sameer Pawar
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(This story appears in the 10 January, 2014 issue of Forbes India. To visit our Archives, click here.)