Jugnu
Uncategorized February 18th, 2009
The following is an article written a while ago, although it was intended to be published elsewhere. Since that didn´t really happen, and most of this information has since been released, I figured I may as well post it here. Its not really up-to-date, the most notable difference being that the team size went up from 30 to about 60 and the meetings now happen throughout the week between much smaller groups.
In a not so nondescript lab in the Northern Laboratories at IIT Kanpur, every Saturday night about 30 students come together for the weekly updates meeting. These students are drawn from 9 departments and range from 2nd year undergraduates to final year M.Tech. students. Guided by about 12 faculty from across the institute and experts from the ISRO Satellite Centre of the Indian Space Research Organization, we are trying to design, fabricate, test, and fly a 3500 cubic centimeter cube made mostly of aluminum alloy and electronics, weighing less than 3 kilograms at an altitude of about 800 km above the Earth´s surface.
The Nanosatellite, named Jugnu, will be IIT Kanpur´s first foray into building complete spacecraft. Scheduled for launch during the first half of the institute´s Golden Jubilee year, Jugnu will first and foremost be a technology demonstrator and a test platform. The typical satellite built by ISRO and other space agencies around the world weighs about 800 kilograms and costs about two orders of magnitude more than what Jugnu will cost. Due to this, flying unproven hardware on such an expensive mission is generally avoided. The trend of construction of nanosatellites to bring space technology to the level of industrial technology is a relatively recent one. Generally spearheaded by universities, about 80 nanosatellites have been launched or are in the process of being built across the world. Jugnu, along with Pratham(IIT Bombay’s satellite),VITSAT( VIT´ Satellite), and StudSat (built by about 8 different colleges) is in the first generation of Indian nanosats. All these 4 satellites are in more or less the same stage of development, give or take a month, and we’re all is waiting to see which one will be the first Indian nanosatellite to be launched into space.
In addition to just proving the nanosatellite platform, Jugnu will study vegetation patters using a Near-IR camera at a resolution of about 280 meters. It will test an indigenous designed and developed Inertial Measurement Unit based on commercial MEMS sensors, as well as the application of GPS in spacecraft navigation. Predominantly indigenous, almost every component on the satellite will have to be designed and tested for its ability to withstand the harshness of the space environment. The vibrations during launch alone will be enough to tear apart a poorly designed system, and that is even before we get to space. In the vast emptiness of space, the satellite´s systems will be exposed to a hard vacuum that can cause plastic materials to evaporate over time. In the absence of convective media such as air, heat dissipation is limited to that by radiation and conduction. The satellite and its systems will be subjected to wide thermal excursions as it revolves around the Earth in its 100 minute orbit, enough to cause commercial grade electronics to degrade over time. The satellite will also be exposed to doses of ionizing radiation, including high energy protons, electrons, and Bremsstrahlung emissions that can potentially cause the satellite´s electronics to get locked up or its memory corrupted.
The satellite is controlled by two independent processors, one a low power 16 bit MCU from Texas Instruments and the other a more powerful ARM7TDMI based controller from Atmel. Even with high efficiency(28%) triple junction solar cells, power is at a premium in space, where every milliWatt of it is to be accounted for. A high fps imaging system will take snapshots of the Earth while the satellite´s orientation is held steady by the Attitude Determination and Control System. Jugnu is designed to be error tolerant by design, with critical systems having redundancies and fail safes to keep the satellite going in case of single point failure. A 12-channel GPS receiver helps determine the satellites position and the Inertial Measurement Unit measures the satellite vibrations. Thermistor temperature sensors measure the temperature of different parts of the satellite and control it by spinning the hot sides away from the sun. Temperature is passively maintained within tolerable limits using Optical Solar Reflectors and Multi-layer Insulation. Tantalum sheets protect sensitive electronics from radiation damage.
We work odd hours and over weekends, attempting to balance our already heavy academic load as well as the work on Jugnu. In addition to finding time to work, we also need to find time to make trips to ISRO at Bangalore, Trivandrum, Ahmedabad, and Lucknow. In the last trip to Bangalore around the 9th of January, about 10 student members and 7 faculty visited ISAC, Bangalore and ISRO headquarters, also home to the Antrix Corporation. There, after Jugnu´s Project Design Review, India´s Secretary for Space and IIT Kanpur´s DORD signed a Memorandum of Understanding between ISRO and IIT Kanpur. In a previous trip in the first week of December, a part of the team not only visited ISAC but also exhibited the project at CII´s SpaceExpo.
Over the next few months, our diverse group of people will put together one of India´s first nanosatellites, learning as we go. Each new week brings new problems with new solutions. Every bump along the way calls for more innovation and improvisation. When Jugnu succeeds, IIT Kanpur would have a tested space platform to push the envelope even further. It would allow us to help miniaturize the electronics in more complex space vehicles and would give us an adaptable vehicle for carrying experiments into orbit.
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