Chandrayaan-3 propulsion module is returned to Earth orbit by India

In an effort to showcase technology that will aid an upcoming Indian lunar sample return mission, the spacecraft that carried the Chandrayaan-3 lander back to Earth orbit has returned.

After a series of maneuvers since October that brought the spacecraft back from a low lunar orbit, the Indian space agency ISRO announced on December 4 that the propulsion module for the Chandrayaan-3 mission is now in a high orbit around the Earth. Earlier, ISRO had not mentioned that it was attempting to bring the propulsion module back into Earth orbit.

For the Chandrayaan-3 lander, the 2,145-kg propulsion module’s primary function was to move it from an initial elliptical Earth orbit to a low lunar orbit. A day after launch on July 14, the module—a modified version of ISRO’s I-3K satellite bus—performed a series of maneuvers to raise the orbit’s apogee, which was followed by a translunar injection burn and induction into the lunar orbit. Next, on August 17, the lander separated from the module, which had entered a nearly circular orbit 150 kilometers above the lunar surface.

On August 23, the lander made a successful landing on the moon. Spectro-polarimetry of Habitable Planet Earth, or SHAPE, is the name of the single instrument that the propulsion module used to observe Earth while it was in orbit. After the lander separated, ISRO gave limited information about the propulsion module.

Declaring in a statement that it was left with over 100 kilograms of propellant on the spacecraft due to the accuracy of the launch and previous maneuvers, ISRO said it made the decision to try to return the propulsion module to Earth orbit. Oct. 9 marked the first maneuver in that plan, which involved increasing the apolune, or high point, from 150 to 5,112 kilometers in its orbit around the moon.

The module executed a transearth injection maneuver on October 13, setting off a course that saw it make four near-misses with the moon before departing its orbit on November 10. Nov. 22, at a height of 154,000 kilometers, marked the spacecraft’s first perigee as it entered a high orbit around the planet.

SHAPE was able to continue its observations nearer to Earth thanks to the maneuver, according to ISRO. But it went on to say that the purpose of the maneuvers was “to demonstrate the mission operation strategies for a sample return mission and derive additional information for future lunar missions.”

A lunar sample return mission has not yet received official announcements from ISRO. Lunar Polar Exploration Mission (LUPEX), a collaborative project with Japan’s Space Agency JAXA, is the company’s next moon mission. Occasionally referred to as Chandrayaan-4, the mission aimed to investigate the south polar region of the moon using an Indian lander and a Japanese rover. At most, 2026 is the anticipated launch date.

Nonetheless, ISRO representatives have talked about the possibility of a sample return mission in the near future. “The government of India has given us a very tight timetable for exploration in space. We need to have a sample return from the moon within about four years,” 24 at the AIAA’s ASCEND conference in Las Vegas, the director of ISRO’s U R Rao Satellite Center, Shri M. Sankaran, stated

He seemed to be referring to the October 17 ISRO leadership meeting, which was presided over by Indian Prime Minister Narendra Modi. The prime minister’s office released a statement that included the following objectives: an Indian space station by 2035; a crewed Indian lunar landing by 2040; however, lunar sample return was not included.

He mentioned, but did not elaborate on, that ISRO had developed a concept for a sample return mission in a later presentation at the conference. “Maybe this sample return and LUPEX mission with JAXA may happen more or less concurrently,”  he said.

Not all of the technologies required for the return of lunar samples on Chandrayaan-3 were demonstrated by the propulsion module’s return to Earth orbit. During the last few days of its mission in September, the lander fired up its engines one last time, soaring 40 centimeters above the moon and landing 30 to 40 centimeters from where it had originally landed. “This ‘kick-start’ motivates sample return and human missions in the future!” ISRO shared content on social media.