Chandrayaan and Mangalyaan: India's Moon and Mars Missions

India's planetary missions are among the most heavily asked rows in Science and Technology, because each one comes with a date, a rocket, a payload list and a record. The Indian Space Research Organisation, founded in 1969 and headquartered at Bengaluru, launches all of them from the Satish Dhawan Space Centre at Sriharikota in Andhra Pradesh, and tracks them through its Deep Space Network at Byalalu near Bengaluru. Four missions matter for an exam: three to the Moon and one to Mars.

Chandrayaan 1, the first Indian mission to the Moon

Chandrayaan 1 was launched on 22 October 2008 on a PSLV C11 rocket and reached lunar orbit in November of the same year. It carried eleven scientific payloads, five of them Indian and six from other space agencies, among them the Moon Mineralogy Mapper supplied by the United States space agency. On 14 November 2008 the spacecraft released the Moon Impact Probe, which carried a painting of the Indian tricolour and struck the surface near the lunar south pole, making India the fourth country to place its flag on the Moon. The greatest result of the mission was the detection of water molecules and hydroxyl on the lunar surface, announced in 2009 from data of the Moon Mineralogy Mapper. Contact with the orbiter was lost in August 2009, after about ten months of the planned two years, but most of its scientific objectives had already been met.

Chandrayaan 2, the first attempt at a landing

Chandrayaan 2 was launched on 22 July 2019 on the GSLV Mark Three, the heavy rocket now called the LVM3. It was a composite of three craft: an orbiter, a lander named Vikram after Vikram Sarabhai, and a small six wheeled rover named Pragyan, meaning wisdom. On 7 September 2019 the lander lost contact during its descent and the soft landing did not succeed. The orbiter, however, was placed correctly and continued to work, and it carries the Orbiter High Resolution Camera, among the sharpest cameras ever sent to lunar orbit. Chandrayaan 2 was the first mission of any country to attempt a landing near the lunar south pole.

Chandrayaan 3, the successful landing

Chandrayaan 3 was launched on 14 July 2023 on the LVM3 M4 rocket. It carried a propulsion module, the lander Vikram and the rover Pragyan, and did not carry a fresh orbiter, because the orbiter of Chandrayaan 2 was already in place. On 23 August 2023 the lander made a soft landing in the high latitude region near the lunar south pole. With that, India became the fourth country to land softly on the Moon, after the Soviet Union, the United States and China, and the first country of any to land in the south polar region. The landing point was named Shiv Shakti Point, and 23 August is now observed as National Space Day. The lander carried instruments for surface temperature, for seismic activity and for the plasma near the surface, along with a laser reflector from the United States space agency. The rover carried two spectrometers, which confirmed the presence of sulphur in the soil and detected aluminium, calcium, iron, chromium, titanium, manganese, silicon and oxygen.

Mangalyaan, the Mars Orbiter Mission

The Mars Orbiter Mission, popularly called Mangalyaan, was launched on 5 November 2013 on a PSLV C25 rocket. Because that rocket could not send the spacecraft to Mars directly, it was first placed in an elliptical orbit around the Earth and raised step by step with repeated engine burns before being flung towards Mars, a method that saved both fuel and cost. The spacecraft entered Mars orbit on 24 September 2014. India thereby became the first country in the world to reach Mars orbit at its very first attempt, the first Asian country to reach Mars, and the Indian Space Research Organisation the fourth space agency to do so. Built for a life of six months, it kept working for about eight years. Its cost of roughly four hundred and fifty crore rupees made it one of the least expensive interplanetary missions ever flown, and the mission was depicted on the reverse of the two thousand rupee banknote.

The payloads of the Mars Orbiter Mission

• Mars Colour Camera, which sent the full disc images of the planet.
• Thermal Infrared Imaging Spectrometer, for surface temperature and composition.
• Methane Sensor for Mars, to look for methane in the atmosphere.
• Mars Exospheric Neutral Composition Analyser, for the thin upper atmosphere.
• Lyman Alpha Photometer, to measure hydrogen and deuterium and study the loss of water.

Why the lunar south pole

The south polar region of the Moon has craters whose floors never see sunlight. Water ice can survive in such permanently shadowed places, and ice would give a future base both drinking water and, when split, hydrogen for fuel and oxygen to breathe. The region also carries very old rock that has not been churned by later lava flows, so it records the early history of the Moon. That is why Chandrayaan 2 and Chandrayaan 3 both aimed for it, and why the successful landing of 2023 mattered beyond the flag.

The names to keep straight

Vikram is the lander, named after Vikram Sarabhai, who is called the father of the Indian space programme. Pragyan is the rover. The Moon Impact Probe belongs to Chandrayaan 1 alone. The propulsion module belongs to Chandrayaan 3 and takes the place of an orbiter. Aditya L1, launched on 2 September 2023 on a PSLV, is a solar mission and not a lunar one, and it was placed in a halo orbit around the first Lagrange point of the Sun and the Earth in January 2024.