It was on 15th August 2003, Independence Day speech, the NDA-1 government’s prime minister Shri. Atal Bihari Vajpayee declared in his typical chase Hindi that India will reach out to the Moon; via the mission called Chandrayaan; meaning an instrument (yaan) meant for Moon (Chandrama). The onus of developing the project fell into the kitty of ISRO (Indian Space Research Organization). As we look back in time; we could gauge the mammoth efforts taken up by ISRO of realizing a spacecraft which would ride on a specifically developed launch vehicle, (more thrust offering PSLV-XL) to travel deep into the space covering an average distance of about 3,84,000 km to the Moon which would take India to all together new platform. History was a mute spectator to similar human efforts when USA’s ranger mission during 1961-65 managed to reach Moon only thrice in its 9-attempts; India making in its maiden effort is commendable; we must appreciate that ISRO was beneficiary to the lessons learned in the past.
The toughest tasks ahead for realizing the project were (in the order difficulty, author’s choice) 1. Building an antenna to receive signals from Moon (greater than 4-lakh km). 2. Developing a special version of rocket to launch the Chandrayaan into lunar transfer orbit (PSLV-XL). 3. Last, but the most challenging part was to decide on what to do on Moon once you make it. While building a 32-m diameter antenna was a huge technological challenge and was accomplished by spending a sizable amount (around 20% of the total cost of Chandryaan project) of funds. A special team of engineers were given the charge to develop a large thrust capacity PSLV at ISROs Mahindragiri facility in Tamilnadu. For meeting the requirements of 3rd challenge; the higher officials of ISRO came up with an idea of calling Opportunity Payloads (OP) from the leading space agencies across the globe. ISRO invited the best players in the field of space exploration to join the Indian project for free lunar ride. This idea clicked so well that almost 50% of the science instruments of Chandrayaan project were of OP category. However, here ISRO, instead of treating the instruments as black boxes, had offered to collaborate with the respective space agencies. It indeed proved to be a boon to ISRO and to the country as a whole.
Since a sequel to this project was to follow; the present project was named, Chandrayaan-I. This project also had an interesting experiment called Moon Impact Probe (MIP) mission, weighing around 32 kg. It was a brainchild of President Kalam, the then president of country, played key role in motivating some of the group of scientists from VSSC (Vikram Sarabhai Space Center) to think about a messenger from our country which would touch the surface of the Moon. Indeed, it is due to this suggestion, India became the 4th country globally to have touched the Moon after USSR, USA, Japan (in order). It was an interesting experiment designed by VSSC-ISRO in the form of MIP; after getting separated from the mother space craft at the northern lunar pole to take around 22-min of descend journey to have an impact near the Malapert mountain in lunar south pole region.
The D-day eventually came on 22nd October 2008 as the PSLV (C-11) launched Chandrayaan-I successfully into initial earth orbit (EO) within few minutes of lift off from Sriharikota. Chandrayaan-I weighed 1380 kg at the time of lift off; which was reduced to 675 kg after burning the fuel contained in Liquid Apogee Motor (LAM). It took another few weeks as the spacecraft was inserted into lunar orbit on 8th November, 2008 and to achieve the successful completion of Moon Impact Probe mission of MIP having impacted on the lunar southern pole on 14th November 2008.
Following is the list of instruments both from India and abroad; detailing their usage.
Scientific Payloads (instruments) from India:
1) Terrain Mapping Camera (TMC); cartographic type, black and white camera
2) Hyper Spectral Imager (HySI); IR-mineral spectrograph
3) Lunar Laser Ranging Instrument (LLRI); Ranger to measure orbital heights precisely
4) High Energy X – ray Spectrometer (HEX)
5) Moon Impact Probe (MIP); an independent probe to have an impact at lunar southern pole
Opportunity Payloads from abroad:
6) Chandrayaan-I X-ray Spectrometer (CIXS): UK, X-ray mineral spectrograph
7) Near Infrared Spectrometer (SIR – 2): Germany, IR-mineral spectrograph
8) Sub keV Atom Reflecting Analyzer (SARA): Sweden, Monitor energetic neutral species
9) Miniature Synthetic Aperature Radar (Mini SAR): USA; Active Radar to probe sub-soil water/ice
10) Moon Mineralogy Mapper (M3): USA, IR-mineral spectrograph
11) Radiation Dose Monitor (RADOM): Bulgaria, X-ray dosimeter The Chandrayaan-I spacecraft settled in a 100-km polar orbit and had successfully worked for the next 10-months completing around 3,400 orbits around Moon successfully before the communication lost happened on 29th August, 2009; for the mission to declare ceased as against a planned 2-year life time around the Moon.
Bottom line:
Chandrayaan-I became the symbol of 1-billion people’s aspiration; it placed ISRO and India on launching pad to any adventurous planetary mission. India became not only a reliable source of space launch vehicle, but at par with the leaders of space-based exploration. As reported in the press, out of the total project cost of around Rs. 380-crores; each rupee spent was justified. Chandrayaan-I provided unprecedented detailed 5-m resolution images (Terrain Mapping Camera) of cartographic nature along with a vast treasure of mineral wealth via Hyper Spectral Images. Even though the mission lasted around 10-months as compared to the planned life span of 2-years; the rigorous observations in this duration had covered more than 90% of lunar surface both in terms of topography and mineralogy. It also brought a century class discovery of water on the Moon. Though the trace amount of lunar water discovery was published by NASA’s Moon Minerology Mapper instrument (remote sensing method); it was India’s own CHACE (Chandra’s Composition Explorer) instrument, part of Moon Impact Probe which observed the in-situ class of experimentation. Chandrayaan-I also brought a wealth of information on the interaction solar radiation with lunar ambiance, finer details on lunar gravitation and enriched awareness among the scientific world in X-ray region. Over all, it brought an unbelievable amount of data and enrichment in the scientific awareness of our next door neighbor in the space.
by Dr. S M Ahmed, Principal Scientific Officer at the University of Hyderabad
