Less than the size of a small car and weighing just 1,350 kg, India’s Mars spacecraft set another milestone today: Mangalyaan began its 100th orbit around Mars. The spacecraft had already completed its prime mission in March, but is still in good health and orbiting around the Martian atmosphere. The cameras and system were found functional till May after it reached ‘blackout phase’ with its orbit taking behind the sun.

Officially called the Mars Orbital Mission (MoM), Mangalyaan is relatively the cheapest successful interplanetary mission by any country in the world. India spent less on the mission than what it cost to make the Hollywood film Gravity. The film’s budget was $100m, whereas MoM cost $74m.

But it wasn’t an easy job for ISRO to successfully send Mangalyan into Mars orbit. Scientists had to make sure the Orbiter left the Earth in a tangential direction when Mars was in the right position and the angle between the Earth, Sun and Mars needed to be approximately 44 degrees, an occurrence which only happens at the interval of 780 days. If ISRO had failed to launch the probe in November 2013, the next window to launch it might not have come for several years. But Mangalyan successfully blasted off in November 2013 on its first attempt and set out, successfully, for Mars. This video by The Curious Engineer explains the basic concept of India’s first ever Mars Orbital Mission with interesting stop-motion animation.