India Says Good Night To Chandrayaan-3

India’s Chandrayaan-3 lunar probe has completed its primary mission and is now in sleep mode. The solar-powered Vikram lander and Pragyan rover were not designed to survive the lunar night, but were fully charged when darkness fell and India’s space agency hopes they might awaken when sunlight returns on September 22.

The Indian Space Research Organisation (ISRO) proclaimed the end of at least this phase of the mission over the weekend. India is the first country to soft land a spacecraft near the Moon’s South Pole.

The South Pole is of great interest because U.S. instruments have detected water there, including NASA’s Moon Mineralogy Mapper on India’s first lunar probe, the 2008-2009 Chandrayaan-1 orbiter.

Chandrayaan-3 landed on August 23 about 600 kilometers (370 miles) from the Moon’s South Pole at 69.36° S, 32.34° E. Indian Prime Minister Narendra Modi said that now will be celebrated as National Space Day and announced the name of the landing site — Shiv Shakti.  India’s first lunar lander, Chandrayaan-2, in 2019 failed when it crashed into the surface, but he decided to give the crash site a name as well, Tiranga.

The Pragyan rover rolled off the Vikram lander and traversed a distance of “over 100 meters” (328 feet).

The rover was rotated in search of a safe route. The rotation was captured by a Lander Imager Camera.

It feels as though a child is playfully frolicking in the yards of Chandamama, while the mother watches affectionately.
Isn’t it?? pic.twitter.com/w5FwFZzDMp

— ISRO (@isro) August 31, 2023

Chandrayaan-3 Mission:

?Pragyan 100*

Meanwhile, over the Moon, Pragan Rover has traversed over 100 meters and continuing. pic.twitter.com/J1jR3rP6CZ

— ISRO (@isro) September 2, 2023

ISRO said Saturday that Pragyan now is safely parked with a full battery and they are “hoping for a successful awakening” when sunlight returns on September 22.  If not, “it will forever stay there as India’s lunar ambassador.”

Chandrayaan-3 Mission:
The Rover completed its assignments.

It is now safely parked and set into Sleep mode.
APXS and LIBS payloads are turned off.
Data from these payloads is transmitted to the Earth via the Lander.

Currently, the battery is fully charged.
The solar panel is…

— ISRO (@isro) September 2, 2023

The lander made a hop just before going into sleep mode itself yesterday, lifting itself up about 40 centimeters (16 inches) and landing 30-40 centimeters (12-16 inches) away.

Chandrayaan-3 Mission:
??Vikram soft-landed on ?, again!

Vikram Lander exceeded its mission objectives. It successfully underwent a hop experiment.

On command, it fired the engines, elevated itself by about 40 cm as expected and landed safely at a distance of 30 – 40 cm away.… pic.twitter.com/T63t3MVUvI

— ISRO (@isro) September 4, 2023

Chandrayaan-3 Mission:
Vikram Lander is set into sleep mode around 08:00 Hrs. IST today.

Prior to that, in-situ experiments by ChaSTE, RAMBHA-LP and ILSA payloads are performed at the new location. The data collected is received at the Earth.
Payloads are now switched off.… pic.twitter.com/vwOWLcbm6P

— ISRO (@isro) September 4, 2023

ISRO communicated Chandrayann-3’s progress and scientific findings over social media including many posts to X (formerly Twitter), including these.

Here are the first observations from the ChaSTE payload onboard Vikram Lander.

ChaSTE (Chandra’s Surface Thermophysical Experiment) measures the temperature profile of the lunar topsoil around the pole, to understand the thermal behaviour of the moon’s… pic.twitter.com/VZ1cjWHTnd

— ISRO (@isro) August 27, 2023

Chandrayaan-3 Mission:

In-situ scientific experiments continue …..

Laser-Induced Breakdown Spectroscope (LIBS) instrument onboard the Rover unambiguously confirms the presence of Sulphur (S) in the lunar surface near the south pole, through first-ever in-situ measurements.… pic.twitter.com/vDQmByWcSL

— ISRO (@isro) August 29, 2023

Chandrayaan-3 Mission:
In-situ Scientific Experiments

Radio Anatomy of Moon Bound Hypersensitive Ionosphere and Atmosphere – Langmuir Probe (RAMBHA-LP) payload onboard Chandrayaan-3 Lander has made first-ever measurements of the near-surface Lunar plasma environment over the… pic.twitter.com/n8ifIEr83h

— ISRO (@isro) August 31, 2023

In-situ Scientific Experiments

Instrument for the Lunar Seismic Activity (ILSA) payload on Chandrayaan 3 Lander
— the first Micro Electro Mechanical Systems (MEMS) technology-based instrument on the moon —
has recorded the movements of Rover and other… pic.twitter.com/Sjd5K14hPl

— ISRO (@isro) August 31, 2023

Chandrayaan-3 Mission:

Anaglyph is a simple visualization of the object or terrain in three dimensions from stereo or multi-view images.

The Anaglyph presented here is created using NavCam Stereo Images, which consist of both a left and right image captured onboard the Pragyan… pic.twitter.com/T8ksnvrovA

— ISRO (@isro) September 5, 2023

The lunar surface gets 14 Earth days of sunlight and 14 Earth days of night as the Moon rotates during its 28-day orbit of Earth. There is no “dark side” of the Moon, only the near side visible from Earth and the far side always pointed away because the Moon and Earth are tidally locked to each other.

We see the Moon as dark during a New Moon when the Sun fully illuminates the far side. The far side is completely dark when we see a Full Moon. Both sides experience the other phases.

For a probe on the lunar surface, surviving the lunar night means lasting 14 days in extremely cold temperatures. Landers and rovers that have endured that environment so far have been equipped with radioisotope heating units or power supplies. Whether Chandrayaan-3’s solar-charged battery can achieve that goal will be an interesting test.