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Debate: MOM’s Low Science Output Reflects Inadequate Science Base, Not on ISRO

Debate: MOM’s Low Science Output Reflects Inadequate Science Base, Not on ISRO

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The Crisp Crater on Sirenum Fossae, Mars. Credit: NASA/JPL-Caltech/University of Arizona.

Recently there has been some criticism of India’s Mars Orbiter Mission (MOM), launched in 2013, particularly its low scientific output in spite of having been operational in Mars orbit for six years.

The Indian Space Research Organisation (ISRO) launched MOM around the same time NASA launched MAVEN, also to the red planet. But while MAVEN’s instruments have supported over 500 research papers thus far, MOM’s instruments have contributed only to 27.

Among many factors cited by the critic, the failure or non-functioning of vital equipment, ISRO’s reluctance to enter into international collaborations and with universities, and lack of long-term science vision have been held responsible for MOM’s unimpressive record. ISRO has also been accused of rushing the project for political considerations, thus restricting the total scientific payload weight to 15 kg.

However, the real reasons only five instruments, from ISRO centres, were approved to fly on MOM was lack of expertise in universities and institutes around India and the lack of options among launch vehicles.

The payload was restricted to 15 kg because ISRO’s Polar Satellite Launch Vehicle (PSLV) could carry 1.4 tonnes in all to the geostationary transfer orbit. More powerful rockets – the GSLV Mk II and Mk III – with a proven track record only became available later. If ISRO had waited for these vehicles, the Mars mission would have been delayed by eight years or so.

Next, let’s consider the Methane Sensor for Mars (MSM) instrument. It can measure trace quantities of methane – in the order of parts per billion (ppb) – and its fabrication was a big challenge. A team at ISRO’s Space Application Center (SAC) developed a novel interferometric design, and realised the instrument in record time. It did not fail; it is still working. The issue is that MSM is sensitive to both methane and carbon dioxide. And the SAC team has published a paper on a way to extract the methane signal along from the instrument’s data, subtracting the interference of other gases.

Likewise, Martian Exospheric Composition Explorer (MENCA) is a mass spectrometer capable of measuring a ppb or lower concentrations of the substances in Mars’s exosphere. However, MENCA can perform its measurements only within the exosphere itself. And this hasn’t been possible thus far thanks to MOM’s orbit, which takes it to within 400 km of the surface.

Deep-dip experiments or manoeuvres are designed to make measurements closer to the lower end of Mars’s upper atmosphere. During normal mapping, measurements are taken at higher altitude, from, say, 150-200 km to 6,200 km. But during deep-dip campaigns, the lowest altitude in the orbit is lowered further, to a point called the periapsis, allowing an instrument to make measurements throughout the entire upper atmosphere. MAVEN’s periapsis was at 125 km. But MOM could deep-dive only up to 265 km – while MENCA needs to be within 100 km of the surface or less.

This may become possible once MOM runs out of fuel and begins to spiral in towards the ground.

Long-term planning

ISRO has a time-tested methodology to select and execute a given project, evolved since the days of Vikram Sarabhai. After the first Satellite Launch Vehicle failed in 1979, ISRO has had external academic experts scrutinise the concept, design and development process.

During the development of the Moon impact probe of Chandrayaan 1, one of us (S.M. Ahmed) deeply interacted with a faculty member at the Tata Institute of Fundamental Research, an ISRO-approved subject expert, from drafting the conceptual design report to the science-planning stage.

In ISRO, the choice of what science is to be done is made by the Advisory Committee on Space Sciences (ADCOS), primarily comprising former directors of ISRO academic centres, like the Physical Research Laboratory (PRL) or the National Atmospheric Research Laboratory. ADCOS identifies experts for each proposed area of science (e.g. geology, atmospherics, etc.), with decadal plans.

At ISRO’s behest, PRL initiated the Planetary Science and Exploration (PLANEX) program in 2001. The idea was to motivate young researchers and provide planetary research facilities in the country, including for remote-sensing, astro-materials, payload development and laboratory/simulation studies of planetary analogues.

Today, a large number of projects are being run in universities and institutes around India that are supported by PLANEX. So saying ISRO isn’t as open as it can be to collaborations with academic institutions may not be entirely fair. For MOM, ISRO centres and academic institutes and universities across the country proposed more than 20 experiments.


While it’s good to compare the quantity and quality of science across nations for the sake of benchmarking, one must not forget the underlying socio-economic differences when doing so.

In almost all scientific endeavours in the West, or even in modern China, universities have played an important role. For example, scientists at universities have been responsible for studying the sedimentary record of ancient rivers, isotopes of hydrogen in the Martian atmosphere and the presence of organic molecules in data from NASA’s Curiosity rover.

The University of Colorado (UC) in particular has been a major space research centre, starting with the Pioneer 1 mission in 1958 and including MAVEN. The twin Voyager spacecrafts that studied the atmospheres of various planets, were all possible due to the UV spectrometers built by a group at UC. MAVEN’s UV Imaging Spectrometer (UVIS) was built by one of the disciples of this group’s leader. (And UVIS alone has ‘generated’ 30-40 scientific papers.)

ISRO knew this, and decided to take a simpler path. It’s very difficult to build a UV experiment, more so one that can work in space. Instead, ISRO scientists decided to study the amount of deuterium in Mars’s atmosphere relative to the quantity of hydrogen. This ratio is used to estimate the rate at which the planet is losing water.

Decades of experience and work are necessary to build any space-worthy instrument. Normally, a research group first develops an engineering model and flies it in a balloon or a rocket into Earth’s lower atmosphere, then to closer destinations like the Moon, and ultimately to farther ones like Mars. A direct ticket to Mars is just absurd and unheard of.

Regarding the number of scientific publications – this is not a straightforward consideration. Data from MENCA has supported a couple of papers in Geophysical Research Letters, a highly respected journal in space sciences. The Mars Colour Camera (MCC) has produced hundreds of stunning images of Mars and has drawn praise for them. The deeper question to ask here is what can be considered useful.

We need to hear from ISRO on the outcomes of the Lyman alpha photometer and the thermal imaging spectrometer payloads. A failure in space can be a great learning experience for the designer. ISRO’s claim that over 1,500 people downloaded over 400 GB of MOM’s one-year data, when it was released in 2016, was impressive – even if it’s also true that these numbers could have been much higher given India’s size.

However, blame for this disappointment doesn’t deserve to be laid at ISRO’s feet. Instead, the issue lies with the sorry state of research in Indian universities. Many of these institutions are neither ready to undertake cutting-edge research in space science nor do their curricula include space science as a subject of study. In fact, more broadly, most universities have been too financially starved to be able to do research of any reasonable quality.

Bigger picture

The lack of university-centric research in India has a historical root. In 1954, Homi Bhaba, then the newly appointed chairman of the Atomic Energy Commission, wrote in a letter to Meghnad Saha: “The role of universities is to do research which extends the frontiers of knowledge or opens up new avenues, while work of a technological nature … which incidentally is far more expensive, should be done in laboratories especially established for the purpose”. This gap has not been bridged to this day.

A cursory look at the allocation on education in India provides further evidence. The government’s total expenditure on education dropped from an already dismal 0.53% of the GDP in 2014 to 0.45% in 2019. As for R&D, the government’s funding has stagnated at about 0.7% of the GDP for several years; and significant chunks of this sliver go to ISRO, the Department of Atomic Energy and CSIR labs.

India has only around 200 researchers per million people, which is lower than the same ratios in China and the US, and even in much-smaller Italy. Together with its lower per capita expenditure on R&D, it’s unfair to compare India’s MOM with the US’s MAVEN. India’s new education policy intends to ramp education expenditure up to 6% of GDP.

This sounds utopian – but until it happens, complaints that our space science missions are not as productive as those created in the west are bound to fall flat.

S.M. Ahmed was formerly a member of Chandrayaan 1’s Moon Impact Probe. He is currently principal scientific officer at the Central Instrumentation Facility, University of Hyderabad. Anindya Sarkar is a professor of geology and head of the National Mass Spectrometry facility at IIT Kharagpur.

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