On this day in space! Oct. 21, 2008: India launches its 1st mission to the moon with Chandrayaan-1

Chandrayaan-1 was India’s first deep-space mission and first mission to the Moon. It had two main parts: an orbiter and the Moon Impact Probe. Together, they allowed ISRO to study the Moon from space and examine its surface directly.

The orbiter remained around the Moon after arrival. It carried 11 scientific instruments, collected lunar measurements, and transmitted data to Earth for about a year. The Moon Impact Probe had a different job. It separated from the spacecraft and crashed into the Moon on Nov. 14, 2008.

This combination made the mission especially useful. The orbiter could repeatedly observe broad areas from above, while the probe performed a controlled impact. Chandrayaan-1 helped demonstrate India’s ability to conduct lunar exploration and contributed evidence of water-related molecules near the Moon’s polar regions.

Chandrayaan-1 began its journey from the Satish Dhawan Space Center aboard India’s Polar Satellite Launch Vehicle, or PSLV-XL. The launch occurred on Oct. 21, 2008, at 8:52 p.m. EDT, which was already about 6:22 a.m. on Oct. 22 at the Indian launch site.

The spacecraft entered lunar orbit on Nov. 8, about three weeks after launch. From there, it released the Moon Impact Probe. The probe struck the lunar surface on Nov. 14, while the main spacecraft stayed in orbit.

The orbiter then observed the Moon with its 11 instruments and sent scientific information back to Earth. It remained in lunar orbit until contact was lost in August 2009. Although the mission ended early, ISRO said it had completed at least 95% of its objectives.

Chandrayaan-1 carried 11 scientific instruments to investigate the Moon. Five were built by the Indian Space Research Organisation, or ISRO. The remaining instruments came through experiments involving other space agencies and research partners.

The article names five countries besides India that contributed scientific equipment: the United States, the United Kingdom, Germany, Sweden, and Bulgaria. Counting India, that means six countries contributed equipment. The mission therefore combined Indian spacecraft development with international scientific participation.

This partnership increased the mission’s scientific reach. Instruments from different contributors could examine lunar features and materials in complementary ways. One American instrument, M3, produced data that later revealed absorption features near the lunar poles. Those findings supported evidence for hydroxyl- and water-bearing molecules on the Moon.

Chandrayaan-1 helped produce evidence that water-related material exists on the Moon. In September 2009, scientists published results from the American M3 instrument carried by the spacecraft. The data showed absorption features in the Moon’s polar regions.

These features are usually associated with hydroxyl- and water-bearing molecules. That interpretation connected Chandrayaan-1’s observations with evidence of water ice on the lunar surface. The spacecraft therefore did more than demonstrate India’s ability to reach the Moon; it also delivered an important scientific result.

The discovery changed the picture of the Moon as a completely dry world. Water-related material became part of the evidence scientists could study when examining lunar poles. The finding also made Chandrayaan-1 a major scientific success, even though the spacecraft stopped communicating before its planned two-year lifetime ended.

Chandrayaan-1 stopped operating before completing its planned two-year mission. Contact with the spacecraft was lost in August 2009, about 14 months earlier than planned. The mission therefore ended abruptly rather than finishing its full schedule.

NASA’s mission overview said the most likely cause was a power-supply failure caused by overheating. Once contact was lost, scientists could no longer receive data or command the spacecraft. This ended the orbiter’s ability to continue its lunar observations.

The early failure did not erase the mission’s achievements. ISRO noted that at least 95% of Chandrayaan-1’s mission objectives had already been accomplished. Before contact disappeared, the spacecraft had entered lunar orbit, deployed the Moon Impact Probe, gathered scientific data, and contributed evidence of water-related molecules near the lunar poles.

Chandrayaan-1 gave India’s space program its first deep-space and lunar mission. It showed that ISRO could launch a spacecraft to the Moon, operate it in lunar orbit, and return important scientific results. That achievement provided a foundation for India’s continued lunar exploration.

India followed with Chandrayaan-2 in 2019. Its orbiter successfully reached lunar orbit, but its Vikram lander failed during landing. The mission still continued the country’s lunar exploration effort through the orbiter.

Chandrayaan-3 followed in 2023 and successfully landed a new Vikram lander and Pragyan rover near the Moon’s south pole. The sequence shows progress from India’s first lunar mission to a successful landing. The article also says India plans Chandrayaan-4 for 2028, with the goal of returning Moon samples to Earth.

A spacecraft stays around the Moon by balancing forward motion with lunar gravity. Its engine places it on a carefully chosen path, called an orbit. Gravity continually pulls the spacecraft toward the Moon, but its sideways motion carries it forward, causing it to keep falling around the Moon instead of hitting the surface.

As it circles, the spacecraft points cameras, spectrometers, and other instruments toward the lunar ground. These instruments measure features such as surface materials and polar regions. Chandrayaan-1 used 11 scientific instruments for this kind of research while remaining in lunar orbit.

The spacecraft then sends measurements to Earth through radio communication. Ground stations receive the signals, process the data, and help control the mission. The source article describes Chandrayaan-1 collecting and transmitting lunar data, but it does not explain the orbital or communication mechanics in detail.