1. The main purpose is to provide an international lab for conducting experiments in space, as the space environment is nearly impossible to reproduce here on earth .
2. The micro gravity environment present in the ISS provides ideal conditions for doing many scientific researches especially in biology, human biology, physics, astronomy and meteorology.

According to Big - Bang theory all the matter in the universe was concentrated in a single point of hot dense matter. About 13.7 billion years ago, an explosion occured and ejected all the matter in all directions in the form of galaxies.

1. The earth is the only planet in the solar system which supports life .
2. Due to its right distance from the sun, it has the right temperature, the presence of water and suitable atmosphere and a blanket of ozone.
3. All these factors have made continuation of life possible on the Earth.

Kepler's three laws of planetary motion.
First Law: The Law of Ellipses
The path of the planets about the Sun is elliptical in shape, with the center of the Sun being located at one of the foci.
Second Law: The Law of Equal areas.
An imaginary line drawn from the center of the Sun to the center of the planet will sweep out equal areas in equal intervals of time.
Third Law: The Law of Harmonies
The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their semi major axis from the Sun.

1. The first four planets Mercury, Venus, Earth and Mars are relatively close together and close to the Sun. They form inner solar system and so they are called as inner planets .
2. They have a surface of solid rock crust and so are called terrestrial or rocky planets .
3. Their insides, surfaces and atmospheres are formed in a similar way and form similar pattern.

Supporting Water - Purification Efforts:
1. Using the technology developed for the ISS, areas having water scarcity can gain access to advanced water filtration and purification systems.
2. This could very well be a life - saving difference for the people in such hazardous locations.
3. The water recovery system (WRS) and the oxygen generation system (OGS) developed for the ISS have saved a village in Iraq from being deserted due to lack of clean water.
Eye tracking technology:
1. The Eye tracking device, built for a microgravity experiment has proved ideal to be used in many laser surgeries.
2. This device tracks the eyes position very accurately without interfering with the surgeon's work.
3.Eye tracking technology is helping disabled people with limited movement and speech.
Robotic arms and Surgeries:
1. Robotic arms developed for research in ISS are providing significant help to the surgeons in removing inoperable tumours and taking biopsies with great accuracies.
2. Robotic arms do heavy lifting in Cancer treatment in the form of surgical robots.
3. ISS technology are useful in the development of improved vaccines, breast cancer detection and treatment, ultrasound machines for remote regions etc.

The first four planets Mercury, Venus, Earth and Mars form inner solar system called as inner planets.
Other, four large planets Jupiter, Saturn, Uranus and Neptune spread out in solar system called as outer planets.
Mercury:
1. It is the first rocky planet nearest to the Sun. It is very hot during day time and very cold during night time.
2. One day is equal to 58.65 earth days and one year is 87.99 days.
3. It moves around the sun faster than any other planet.
4. It always appears in the eastern horizon or western horizon of the sky.
Venus:
1. It is the second brightest and hottest planet almost the same size as that of the earth.
2. A day of venus is longer than its year. Day is 243 earth days and year is 224.7 earth days
3. It spins in the opposite direction to all the other planets and so sun rises in the west and sets in the east here.
4. It appears in the horizon of eastern or western sky.
The Earth:
1. It is the third planet in the solar system which supports life.
2. Due to its right distance from the Sun, it has the right temperature, the presence of water and suitable atmosphere and a blanket of ozone.
3. It moves around the sun in 365.25 days and its rotation period is 24 hours.
4. It is slightly tilted on its own axis, due to that, seasons are possible on earth .
5. Earth appears bluish green due to the reflection of light from water and land mass on its surface
Mars:
1. It appears slightly reddish and so it is called as Red planet. It is the fourth planet in solar system.
2. It has two small moons called Deimos and Phobos.
3. One day on this planet is of 24 hours 37 minutes and one year is 687 earth days.
Jupiter:
1. It is the fifth planet and called as Giant planet
2. It is the largest and fastest planet having 3 rings and 65 moons.
3. Its moon Ganymede is the largest moon of our solar system.
4. One day is 9 hrs 55 min. One year in Jupiter equals earth's 11.86 years.
Saturn:
1. It is the sixth and yellowish planet having bright shiny rings.
2. It is the second biggest and giant gas planet in the outer solar system.
3. It rotates very fast, being 10.7 hours and revolution period 29.46 Earth years.
4. It has 60 moons, the largest one is Titan.
5. It is the only moon in the solar system which has clouds.
Uranus:
1. It is a cold gas giant and seventh planet of the solar system.
2. It has greatly tilted axis of rotation.
3. Its revolution period is 84 earth years and the rotation period is 17.2 hours.
4. Due to its peculiar tilt, It has the longest summers and winters each lasting 42 years.
Neptune:
1. It appears as greenish star. It is the eighth planet from the Sun and is the windiest planet.
2. Every 248 years, Pluto crosses its orbit.
3. It has 13 moons - Triton being the largest and it is the only moon moves in the opposite direction to the direction in which its planet spins.