Chandrayaan-3: landing module does not wake up after lunar mission – 09/25/2023 – Science

As the sun rose Friday over the lunar plateau where the Vikram lander and India’s Pragyan rover sit, the robotic explorers remained silent.

ISRO (Indian Space Research Organization), equivalent to India’s NASA, said last Friday (22) that mission controllers on the ground sent a wake-up message to Vikram.

As expected, the lander did not respond. Efforts will continue in the coming days, but this could very well be the conclusion of Chandrayaan-3, India’s first successful space mission to the lunar surface.

India is only the fourth country to achieve an intact landing on the Moon, after the United States, Russia and China. Vikram, which arrived a month ago, was also the first spacecraft to land in the Moon’s south polar region, which has become an area of ​​intense scientific curiosity in recent years.

Shortly after landing in August, the small Pragyan rover rolled down a ramp and began moving. Over the next week and a half, as the sun moved across the sky, the two solar-powered spacecraft studied their surroundings, measuring underground temperatures, identifying elements in the lunar soil and listening for lunar tremors.

As the sun began to set, ISRO (Indian space agency) officials sent commands to put Vikram and Pragyan to sleep. His batteries were fully charged, and Pragyan’s solar panels were pointed toward where the sun would rise again.

The hope was that when sunlight heated the solar panels again, the spacecraft would recharge and revive. But that was optimistic thinking. Neither Vikram nor Pragyan were designed to survive a long, cold lunar night, when temperatures drop to more than 100 degrees below zero, far colder than the electronics were designed to withstand. The spacecraft’s designers could have added heaters or used sturdier components, but this would have increased cost, weight and complexity.

Even if the spacecraft are not revived, the mission, called Chandrayaan-3, was a success for ISRO, alleviating the disappointment of four years ago when its first attempt to land on the Moon ended in an accident during the Chandrayaan-2 mission.

Undeterred, ISRO built a copy of the failed landing module — correcting deficiencies in the original design — and tried again. This time, on August 23, the landing went smoothly. With Prime Minister Narendra Modi watching via video conferencing, the control room erupted in applause when Vikram’s safe arrival was confirmed.

“The triumph of Chandrayaan-3 mirrors the aspirations and capabilities of 1.4 billion Indians,” Modi said afterwards, describing the event as “the moment for a new and developing India.”

The mission’s scientific observations included a temperature probe deployed from Vikram that penetrated the lunar soil. The probe recorded a sharp drop, from about 120 degrees Fahrenheit (about 49 ºC) at the surface to 10 degrees ºF (-12.2 ºC) at just 7.6 cm deep. Lunar soil is a poor conductor of heat.

Poor heat conduction could be an advantage for future astronauts; an underground outpost would be well insulated from the huge temperature variations on the surface.

Another instrument on Vikram, a seismometer, detected on August 26 last what appeared to be a lunar tremor.

Pragyan covered more than 300 feet (91 meters) in total. As he drove, he fired laser pulses at rocks and soil, allowing him to identify elements based on the colors of light emitted by the vaporized material. The instrument confirmed the presence of elements such as aluminum, calcium, iron and titanium. Somewhat surprisingly, he also found sulfur.

Traces of sulfur were measured in lunar soil and rock samples brought back to Earth by NASA’s Apollo astronauts and Soviet robotic spacecraft decades ago. Pragyan’s measurement suggests that sulfur concentrations may be higher in polar regions. Sulfur is a useful element in technologies including solar cells and batteries, as well as being used to make fertilizers and concrete.

Before going into hibernation this month, Vikram made one final small move, firing its engines to rise about 41cm above the surface before gently landing again. The jump changed Vikram’s position by 30 to 40 cm, ISRO said.

“Waiting for a successful awakening to another set of tasks!” ISRO posted on X, formerly known as Twitter, on September 2. “Otherwise, he will remain there forever as India’s lunar ambassador.”