Chandrayaan-3 soft landing: What are the different kinds of moon missions?

The eagerly anticipated Chandrayaan-3 mission by ISRO is poised to achieve a historic lunar landing following a 40-day voyage. Expected to occur on August 23, approximately at 6:04 pm, the Lander Module of Chandrayaan 3 is anticipated to make a soft touchdown on the lunar surface. This composite module includes both the Vikram lander and the Pragyan rover, both of which carry a suite of experimental payloads aimed at advancing lunar research.

Over the past fifteen years, there has been a revitalized interest in lunar exploration. Following the conclusion of the last Apollo mission in the early 1970s, there was a prolonged period of minimal activity directed towards lunar exploration due to having exhausted the technological capabilities of that era. While there were some initiatives in the 1990s, the true resurgence occurred after Chandrayaan-1's mission in 2008, which made the groundbreaking discovery of water's presence on the lunar surface. This discovery fueled a fresh wave of enthusiasm for lunar exploration.

Here is a categorization of the diverse types of moon missions launched thus far:

Flyby missions entail spacecraft passing in close proximity to the Moon without establishing an orbit. These endeavors serve to examine the Moon remotely or as a means to reach other celestial bodies or venture into deep space. Early instances encompass the US Pioneer 3 and 4, along with the USSR's Luna 3.

Orbiter missions encompass spacecraft designed to enter lunar orbits, enabling sustained investigations of the Moon's atmosphere and surface. Noteworthy among these is India's Chandrayaan-1, along with 46 other lunar missions from diverse nations. Orbiters constitute a prevalent approach to scrutinizing planetary bodies. The Chandrayaan-2 mission also comprised an operational orbiter, which continues to circle the Moon at an altitude of roughly 100 km.

Impact missions, an extension of orbiter endeavors, involve the main spacecraft maintaining its lunar orbit, while one or more instruments from it perform an uncontrolled landing on the Moon's surface. These instruments transmit valuable information during their descent despite their ultimate destruction upon impact. An example of this is the Moon Impact Probe (MIP) from Chandrayaan-1, which similarly crash-landed and supplied data that supported the notion of water presence on the Moon.

Lander missions necessitate the gentle touchdown of spacecraft on the Moon's surface. These missions are more intricate than orbiter projects, with the initial 11 lander attempts ending in failure. The USSR's Luna 9 achieved the first successful Moon landing on January 31, 1966, and also transmitted the inaugural image from the lunar surface.

Rovers are specialized wheeled payloads transported by landers, capable of detaching and exploring the Moon's surface. They collect invaluable data beyond the capacity of instruments within the lander. An example is the Pragyaan rover, part of the Vikram lander in the Chandrayaan-2 mission.

Human missions involve astronauts landing on the Moon's surface. Currently, NASA of the United States stands as the sole entity to have achieved this feat.

Flyby missions involve spacecraft passing near the Moon without entering its orbit. These missions are either aimed at distant observation of the Moon or en route to other celestial bodies.

Early instances include Pioneer 3 and 4 by the United States and Luna 3 by the USSR.

Orbiter missions encompass spacecraft designed to enter lunar orbit for extended studies of the Moon's surface and atmosphere.

India's Chandrayaan-1 was an Orbiter, as were 46 other missions from various nations. Orbiter missions are a prevalent approach for planetary exploration. Chandrayaan-2 also featured an operational orbiter circling the Moon at an altitude of around 100 km.

Impact missions extend the capabilities of Orbiters. While the primary spacecraft continues orbiting, certain instruments aboard perform uncontrolled landings on the Moon. Despite destruction upon impact, they transmit valuable data during descent.

Chandrayaan-1's Moon Impact Probe (MIP) similarly crash-landed, contributing evidence of lunar water presence.

Lander missions entail safely landing spacecraft on the Moon. These are more intricate than Orbiter missions. Initial attempts faced failures, but the USSR's Luna 9 succeeded in the first lunar landing on January 31, 1966, transmitting the inaugural picture from the lunar surface.

Rovers are specialized wheeled payloads carried by landers. They detach and explore the Moon's surface, collecting distinct information unattainable by lander instruments. Chandrayaan-2's Vikram lander featured the Pragyaan rover.

Human missions comprise astronauts landing on the Moon. NASA, the United States' space agency, remains the sole entity to achieve this feat thus far.