India and Space

India and Space

India and Space : History and Future

This post was written by Kushagra Srivastav, Pranav R Iyengar and Ravi Suthar for the second SpaceWalk by STAC IIT Mandi.

SpaceWalks is a series of talks by speakers from the STAC community, on various topics in the fields of Space Technology and Astronomy.

Humanity is curious about the cosmos and wants to know all about it. The scientific urge to know the unknown led to the exploration of every element of space by numerous agencies such as ISRO and NASA. As long as there has been an imperceptible desire to explore and examine what we know and where we have been, our society has benefited from this. This desire was born from the efforts of our ancestors, from the ones who liked to be in the company of stars. Indians are believed to be the pioneers of astronomy in the world.


Astronomers, our predecessors were fascinated by the things they observed in the night sky. They expressed their curiosity by by writing texts which are now recognized as greatest contributions in astronomy. We will take a quick peek into some of those great works:

Surya Siddhanth

It’s the earliest of the Siddhantas, or traditions, in Vedic archaeo-astronomy. Because it portrays Earth as a sphere, not a flat surface, and gravity as the cause of things falling to Earth, it is the oldest book in the world to do so. Last revised in 580 AD, it is believed to have been composed around 12000 BCE. It was written in ancient Indian poetic style.

Surya Siddhanth has details on trigonometry, Kepler’s 2nd law, sidereal period of every planet with high accuracy, time dilation and many more astronomical topics.

Vedang jyotishya

It was Written in 1400BCE, Written by Lagadha it has details of the seasons, solstice solar year itch. As we all Indians were stalwarts in astronomy, let us look at some of our genius ancestors who laid the foundation of curiosity and instill the spirit of discovery in us.

Aryabhata (476AD-550AD)

Statue of Aryabhatta

Aryabhata wrote many treatises on astronomy and mathematics, some of which are lost. He is most known for his famous compilation, Aryabhatiya. This work has been frequently cited in Indian mathematical literature and has lasted to the present day.

There are different types of trigonometry in the Aryabhatiya: plane trigonometry and spherical trigonometry.

Continuing fractions, quadratic equations, sum-of-power series, and a sine table are all included in the book.

Bhaskaracharya (1114AD-1185AD)


In many ways Bhaskaracharya represents the peak of Mathematical knowledge in the 12th century. He reached an understanding of the number systems and solving equations which was not to be achieved in Europe for several centuries. As far as astronomical works go, Bhaskaracharya’s “Siddhanta Shiromani” is the best. It’s rightly referred to as the “essence of ancient Indian Astronomy and Mathematics.”


We all now know how the foundation was laid, But the concepts developed at that time were also brought into use. This is evident from the calendars that were developed, that had astronomical calculations and positions of stars at their core. Ever wondered how those were created?

Ancient writings

Because the passage of the sun and the moon are the most visible natural, regularly occurring phenomena helpful for timekeeping, global lunation and the year were most often employed as time units in pre-modern cultures. Nonetheless, the Roman calendar included vestiges of a pre-Etruscan 10-month solar year. The Bronze Age Egyptian and Sumerian calendars were the earliest recorded tangible calendars, owing to the emergence of writing in the Ancient Near East.

Vedic India created a complex timekeeping system as well as calendars for Vedic ceremonies.

  • Sidereal day:
    A sidereal day determines the rotation of the Earth with respect to the stars rather than the sun. It enables astronomers to keep time and aim their telescopes without having to worry about the Earth’s orbit.
    The Earth spins around its axis once every 23 hours, 56 minutes, and 4 seconds, which is referred to by astronomers as a Sidereal Day.
  • Solar day:
    The apparent solar day is the period between two successive Sun transits over the same meridian. Because the Earth’s orbital motion causes the Sun to appear to move slightly eastward relative to the stars each day, the solar day is about four minutes longer than the sidereal day; i.e., the mean solar day is 24 hours 3 minutes 56.555 seconds of mean sidereal time; the sidereal day is more commonly expressed in terms of solar time, being 23 hours 56 minutes 4 seconds of mean solar time.

Lunisolar calendar

By definition, a lunisolar calendar is based on the orbital motion of the Sun and the Moon as observed from the Earth (i.e. in a geocentric model).

The solar months (Rashis) are nothing but the familiar signs of the Zodiac, labeled in a different language (Sanskrit). A solar day is defined based on the axial rotation of the Earth.

The lunar days and months are defined based on the position of the Moon relative to the Earth-Sun axis (i.e. its synodic position).

Indian Calendar

One kind of our traditional calendars is based on sidereal year. The year begins when sun at a fixed point (opposite to star Chitra) Aries begins from here and each 30 degree another zodiac comes, this used to be vernal equinox(Visuva) in 285 BCE.

It contains 12 masses (months, having unequal length) theses are determined by the phases of moons since lunar and solar both months are there and 6 Ritus (seasons). These are named after the zodiac occupied by the sun.

Mithuna is the longest, and Dhanu is the shortest month. In Indian calendars, start and ends of months are according to a model of solar system called as Surya-Siddhanta.


Yuga in Hinduism is an epoch or era within a four age cycle. There are four Yugas in one cycle:

  • Satya Yuga ~ Golden age: a time of truth and righteousness
  • Treta Yuga ~ Silver age
  • Dwapara Yuga ~ Bronze age
  • Kali Yuga ~ Dark age: a time of darkness

A binary system

A binary star is a star system consisting of two stars orbiting around their common barycenter (i.e., center of mass of two or more bodies that are orbiting each other). This is a theory from ancient times about stars and the Yugas - Binary stars

Astronomical observations indicate that Earth’s Sun’s System and another Star system are traveling around the Galaxy as a unit, as a “sector”. We slowly revolve around one another as we both revolve around the Galactic Center. There is a “gravitational attraction” between both stars. This movement of the solar system occurs because the Sun has a companion star; both stars orbit a common center of gravity, as is typical of most double star systems. The grand cycle–the time it takes to complete one orbit––is called a “Great Year,” a term coined by Plato.

Just as the spinning motion of the earth causes the cycle of day and night, and just as the orbital motion of the earth around the sun causes the cycle of the seasons, so too does the binary motion cause a cycle of rising and falling ages over long periods of time, due to increasing and decreasing electromagnet effects generated by our sun and other nearby stars.

Binary stars

Whenever our sun’s solar system come close to the other star system, it is known as Satya yuga (Golden age), all the creatures living in our system rise to greater possibilities. Whenever our sun’s solar system moves away from the other star system it is know as Kali yuga(Iron age), all the creature living in our system come to lowest possibilities.

Modern India in space

An ISRO rocket

The end of colonial authority was a significant milestone worth commemorating, but what lay ahead was a lengthy road to the creation of modern India. The stories of institutions that helped shape India as we know it now would be insufficient to complete the story of modern India.

The Indian Space Research Organisation, established in 1969, succeeded the previous INCOSPAR. Vikram Sarabhai, having recognised the significance and relevance of space technology in the development of a nation, gave ISRO the essential direction to act as a development agent. ISRO subsequently set out on its objective to deliver space-based services to the nation while also developing the technology to do so independently.

As a service to the nation ISRO has developed and launched various projects - we will take quick tour of some of them :

  1. Aryabhatta satellite
    Originally named after the great Indian astronomer, Aryabhata was India’s first satellite. Kapustin Yar, a Soviet rocket launch facility in Astrakhan Oblast, launched it on 19 April 1975 using the Kosmos-3M launch vehicle. Built by ISRO, it was launched under the Soviet Inter-kosmos programme, which gave friendly governments access to the space programme.
  2. Mars Orbiter Mission
    MOM, or Mangalyaan, is a space probe launched on November 5, 2013 by the Indian Space Research Organization (ISRO).

    India’s first interplanetary mission was Mangalyaan. The space probe has been orbiting Mars since September 24, 2014. The spacecraft was manufactured in the United States. As a result of the expedition, India is now the first Asian country and fourth in the world to reach Pluto, after Ros cosmos, NASA and the European Space Agency Chinese media called India’s Mangalyaan the “Pride of Asia.”

    On September 24, 2018, MOM completed four years in its orbit around Mars, although the designed mission life was only six months. ISRO now plans to develop and launch a follow-up mission called Mars Orbiter Mission 2 (MOM-2 or Mangalyaan-2) in 2024.

There is a natural interest in space, defence, aeronautics, and satellites in India. Several space missions have been carried out with the help of Indian astronauts, who are among the greatest in the world. Private firms can now participate in satellites, launches, and space- based services as a result of a government policy issued earlier this year.

The future of India in space looks as bright as the sun !

ISRO rocket taking off

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