The Indian Space Programme has the primary goal of promoting and establishing a vibrant space science, applications and technology programme to assist in the overall development of the nation. Right from its inception, pursuit of space research is one of the important objectives of the Indian Space Programme. The Thumba Equatorial Rocket Launching Station (TERLS) was established near Thiruvananthapuram in 1963 for studying the ionospheric electrojet and related phenomena, which opened up a new chapter in space research activities in the country.

Also, the first Indian satellite, Aryabhata, launched in 1975, carried scientific experiments to investigate X-ray astronomy, solar neutrons and supra-thermal electron density. Since then, several instruments for scientific research have been flown on board high altitude balloons, sounding rockets and satellites. Several ground based facilities have also been set up for conducting research by scientists from universities and research institutions as part of astrophysical, solar and atmospheric research programmes.

India has a vast experience in developing and launching operational spacecraft systems for survey and management of natural resources, meteorological services and satellite communication. Technologies developed for those spacecraft systems, which are readily available now at ISRO, can be fully exploited for embarking on planetary missions with well thought out scientific objectives. The Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV) of ISRO are capable of undertaking missions to the Moon and other nearby planets. The technical capabilities acquired by India and the enthusiasm of modern Indian scientists in exploring the Moon, prompted ISRO to undertake - Chandrayaan-1, India’s first mission to the Moon. The primary objectives  of the mission are to expand knowledge about the origin and evolution of the Moon, further upgrade India’s technological capabilities and provide challenging opportunities to the young scientists working in planetary sciences.

The idea of an Indian mission to the Moon was initially mooted in a meeting of the Indian Academy of Sciences in 1999 that was followed up by discussions in the Astronautical Society of India in 2000. Based on the recommendations made by the learned members of these forums, a National Lunar Mission Task Force was constituted by the Indian Space Research Organisation (ISRO) with leading scientists and  technologists from all over the country for considering and making an assessment of the possible configuration and feasibility of taking up an Indian Mission to the Moon.

A peer group of more than hundred eminent Indian scientists representing various fields of planetary and space sciences, earth sciences, physics, chemistry, astronomy, astrophysics, engineering and communication sciences deliberated on the Study Report of the Task Team in 2003 and unanimously recommended that India should undertake the Mission to the Moon, particularly, in view of the renewed international interest with several exciting lunar missions planned for the new millennium. In addition, such a mission will provide the needed thrust to basic science and engineering research in the country, including new challenges to ISRO to go beyond the geostationary orbit.

The Chandrayaan-1 mission will be an important catalyst for the youngsters to pursue fundamental research. The academia, in particular, the university scientists would find participation in such a project like Chandrayaan-1 intellectually rewarding. Government of India approved ISRO’s proposal for the first Indian Moon Mission, called Chandrayaan-1, in November 2003. 

“MOON”, our closest celestial neighbour, has aroused curiosity much more than any other object in the sky. Moon has been worshipped as deity in different mythologies, called as Chandra / Soma in Indian, Luna in Roman, Selene in Greek and Chang’e in Chinese civilization. One of the oldest Indian scriptures ‘Àgveda’ which originated in Indus valley civilization states.

O Moon! We should be able to know you through our intellect,

You enlighten us through the right path.

Rugveda Part – I/91/1

(About 2000 years B.C)

The Moon with the early history of the solar system etched on it, challenges mankind from time immemorial to discover its secrets and admire its marvels. Understanding the Moon provides a pathway to unravel the early evolution of the solar system and that of planet Earth.

The Moon

The Moon is the brightest object in the night sky, fifth largest satellite of the solar system and only second in brightness to that of the Sun. The Moon orbits the earth at a distance of about 384,400 km, has a diameter of 3,476 km and a mass of 7.35×1022 kg with a mean density of only 13.35 gcm-3 as compared to 5.52 gcm-3 of that of the Earth. It has no atmosphere and outgassing from the surface is negligible. The gravitational force on the Moon is only one sixth of that of the Earth, and not capable of retaining an atmosphere. The absence of any atmosphere causes the Moon to undergo extremes in temperature. The side of the Moon receiving sunlight becomes scorching hot reaching 130 °C. the night side of the Moon reaches freezing cold temperature of -180 °C. The Moon does not have a substantial core of molten iron like Earth and hence, has no intrinsic magnetic field; but it has weak, scattered, localized magnetic anomalies.

An interesting fact is that the Moon always has the same side facing the Earth. This is because Earth’s gravity has slowed the Moon’s rotation in such a way that the rotation time just matches the time it takes to go around the Earth. The Moon’s rotation period around its axis and revolution period around the Earth are same and is about 27? days. Therefore the Moon’s day is equal to its year. The time taken from one new Moon to another new Moon (synodic period) is about 29½ days.

 India’s unmanned lunar spacecraft Chandrayaan-1 on Wednesday successfully entered the operational lunar orbit after ISRO scientists carried out final orbit reduction manoeuvre, lasting one minute.

The craft is now at a circular orbit of 102 km above the moon’s surface, ISRO spokesperson S Satish said.

It is expected to be trimmed to 100 km — the final circular orbit of Chandrayaan-1 — tomorrow, he said.

On November 9, India became the fifth member of the global moon club with Chandrayaan-1 entering the lunar orbit at 5.04 pm (IST). The other four members are the US, Russia (former Soviet Union), Japan, China and members of European Space Agency (ESA).

According to Isro officials, Chandrayaan’s liquid engine was fired for 817 seconds when the spacecraft passed at a distance of about 500 km from the moon to reduce its velocity to enable the lunar gravity to capture it around the moon. Chandrayaan’s speed was reduced to 366 metres per second when it flew into the moon’s orbit.

Experts said it was a significant feat because India’s moonshot was successful in the very first attempt — something that even major space powers like the US and Russia could not achieve. The man who launched the Indian moon mission, Krishnaswamy Kasturirangan, had said, “It’s undoubtedly a great moment for India because nearly 50% of the moon missions of other countries have not been successful.”

Chandrayaan-1, the two-year Rs 386 crore Indian moon mission launched from Sriharikota on October 22, will draw a three-dimensional map of the moon, carrying out its chemical mapping and hunting for water or ice.

Kasturirangan said the lunar orbit insertion (LOI) was a nail-biting moment because two objects — the moon and Chandrayaan — moving at a high speed had to have a successful rendezvous. At a certain point, the gravity of moon and that of earth cancel each other out, making LOI very challenging.