indianexpress.com | Nov 30th -0001Amitabha Ghosh
: Tue Nov 05 2013, 10:40 hrs
ISRO should explore new frontiers, not replicate what's been done by others.
It's not always a great idea to ask questions during a countdown. More so when it's a mission to Mars by the Indian Space Research Organisation (ISRO) at a time when the dominant mood in the country is one of gloom. But ask we must, given how ISRO has been one of Indian science's few success stories. Despite and because of its recent string of failures.
Indeed, one of the biggest technology priorities for ISRO should be to complete the development of the Geosynchronous Satellite Launch Vehicle (GSLV). The GSLV, which has been under development for more than a decade, has held up ISRO's progress in earth science, space science and human spaceflight. Since the GSLV is not operational, ISRO is constrained to use the much less powerful Polar Satellite Launch Vehicle (PSLV) to further its ambitions in space. The PSLV can launch about 3,250 kilogrammes to low Earth orbit (LEO). To put this in the context of the capability of launch vehicles, this is less than 1/25 of the largest launch vehicle, the Saturn V, which launched astronauts to the moon. Launch vehicles used for planetary missions are significantly more powerful than the PSLV. The Atlas V, which was used to launch the Curiosity rover, can deliver three to six times the mass to LEO. ISRO has taken more than 15 years to develop the GSLV. Compare this to the time taken by other organisations to develop similar launch vehicles — a startup company called SpaceX started from scratch and operationalised the Falcon 9, which can deliver about two times the mass the GSLV can to LEO, in about seven years.
A possible priority for ISRO should have been to follow up Chandrayaan-1, with which it made significant progress in planetary exploration, with a more capable lunar mission. Contrary to popular perception, Chandrayaan-1 did not fulfil its design requirements. The spacecraft did not complete its nominal (planned) mission of two years — it ended in less than a year. A majority of orbiters meet or exceed the duration of their nominal mission. From the outset, there were thermal problems that caused the spacecraft to overheat. Raising its orbit towards the end of the mission did not prevent this. There were serious problems with the navigational system, which crippled the spacecraft's capability to determine its orientation in space. ISRO also lost contact with Chandrayaan, the reason for which could not be unambiguously established. An argument can be made that ISRO should have embarked on Chandrayaan-2, to address the shortcomings of Chandrayaan-1, before embarking on Mangalyaan, which inserts additional complexities like latency — the time taken for a radio signal from Mars to travel is tens of minutes, compared to the near-instantaneous signals from the moon. And deep space communication — the distance to Mars is twice the distance between Earth and the moon.
Another possible priority for ISRO should have been to further its aspirations in human spaceflight. In 2007, it had announced India's plans to launch humans in space by 2016. Little headway has been made in that direction. China, in comparison, has launched astronauts in space and is on track for launching its own space station in the next 10 years. There is also the question of whether a human spaceflight programme is even relevant in the 21st century, which has ushered in the era of cheaper robotic exploration of planets.
Instead of focusing on other priorities, ISRO has chosen to undertake a Mars Orbiter Mission. Mangalyaan will enable the organisation to develop its capability in deep space communication, though it's unclear to what extent NASA's deep space network would help ISRO and to what extent it will develop its own capability. Also, the mission will help ISRO learn how to operate a spacecraft under latency.
Since 1996, NASA and the European Space Agency (ESA) have launched four orbiters (Mars Global Surveyor, Mars Odyssey, Mars Reconnaissance Orbiter and Mars Express), four rovers (Pathfinder, Opportunity, Spirit and Curiosity) and one lander (Phoenix). Each of these has flown a variety of scientific instruments to Mars. Because of its limited instrument payload and mapping orbit, Mangalyaan is unlikely to add to the breadth or quality of data generated by other Mars missions. For example, Mangalyaan will strive to measure Martian topography. But the laser altimeter onboard the Mars Global Surveyor has already made 640 million elevation measurements and has produced a very detailed topographic map of Mars. It's unlikely that Mangalyaan will significantly add to our understanding of Martian topography.
To wait until the GSLV was operational, rather than use the PSLV, would have been better for a scientific mission to Mars. This would have allowed the use of more instruments for a comprehensive investigation. The science payload for Mangalyaan (15 kg) is significantly less than that for a comparable orbital mission like the Mars Express (116 kg).
Mangalyaan will strive to measure the methane abundance of Mars. In this context, it is significant that the Curiosity rover has not been able to find methane in the parts per million range on the surface of the planet — the upper limit for methane abundance is 1.3 parts per billion. This dims the hope that Mangalyaan will be able to detect it. Also, its detection does not amount to evidence of life on Mars. A scientific case needs to be made as to why the methane should be biogenic or related to life. The presence or absence of a methane signature from orbit is not definitive evidence for the presence or absence of Martian life.
The risk profile of Mangalyaan is of significant concern. Given that India is launching its first mission to Mars, the 15 months taken to develop the spacecraft is worrisome. To put this in context, NASA/ESA missions have 36-48 months of development time and a significant portion of their hardware has been validated on previous missions. The failure rate of missions to Mars is greater than 50 per cent. A long and thorough developmental schedule would have ensured the necessary engineering rigour to maximise the chance of a successful mission. It is possible that Mangalyaan has been in development for a much longer period than what is officially acknowledged. But if the development time was as announced, this might translate into serious technology risks and the threat of mission failure. Launch windows to Mars occur once every two years. If the developmental schedule was hastened to catch the launch window, it could be a severe misjudgement. It might have been worthwhile to extend the development schedule and wait for the next launch window in 2015. If ISRO pulls off a picture-perfect mission, it will be setting a new global standard in spacecraft development under schedule pressure.
If successful, Mangalyaan will replicate what NASA accomplished in the 1960s and 1970s. While this is admirable, given that very few nations have successfully orbited Mars, it would hardly be a novel accomplishment in the world of technology. ISRO need not recreate what has already been done. To be relevant, it should chart its own unique trajectory of frontline discoveries that will leave an imprint on space science and technology.
The indirect benefit of a successful mission would be a change in the perception of India in foreign policy, business, culture and beyond. In the 1990s, in the eyes of the world, India went from being a country known for its ancient traditions to a country of technology-literate people adept at programming. A successful Mangalyaan would change the way Indian are viewed — from technocrats to scientists, engineers who can successfully take on problems on the frontiers of technology.The writer is a science operations working group chair on the NASA Mars Exploration Rover Mission. Views are firstname.lastname@example.org