The Vikram lander houses the six-wheeled Pragyaan rover. The lander module was released by the Chandrayaan-2 orbiter in early September (Illustration: Reuters)
- Isro lost contact with Vikram during its descent on to the Moon on September 7
- The Chandrayaan-2 orbiter is performing well and is in orbit around the Moon
- The orbiter will operate for around 7 years and conduct several operations
The silent Vikram lander of the Chandrayaan-2 mission is likely to remain silent forever. The lander lies on a part of the Moon where a cold night is descending fast. Temperatures in the area will plunge to less than minus 200 degrees Celsius. This means that even if Vikram survived its September 7 lunar descent during which it lost contact with Earth, the lander's instruments will be frozen out of operation during the cold lunar night.
The Indian Space Research Organisation has yet to confirm Vikram's current status. But, in the last few days, the space agency has dropped hints that hopes for re-establishing communication with the Vikram lander, which houses the six-wheeled Pragyaan rover, have ended.
On Tuesday, Isro put up a cryptic tweet in which it thanked everybody for "standing by" the space agency and promised to "continue to keep going forward". Then on Thursday, Isro offered an update on the Chandrayaan-2 orbiter, noting that the spacecraft was performing well in its orbit around the Moon and was carrying out its experiments.
The mission update had a mention of the Vikram lander: A national-level team of academicians and Isro scientists was looking into why contact with Chandrayaan-2 lander was lost. Curiously, Isro chose not to repeat its boilerplate statement that it was making all efforts to get in touch with the Vikram lander.
And now, with hours to go before night fully descends on the part of the Moon where Vikram is, it probably is time to bid the lander goodbye.
WHAT HAPPENED ON SEPTEMBER 7
The Vikram lander, which had separated from the Chandrayaan-2 orbiter early in September, began its descent in the early hours September 7.
- Initially, everything seemed to be going right according to plan. Scientists at the Isro control centre in Bengaluru were seen cheering and clapping as Vikram aced the various stages of its descent.
- Around 10 minutes into the 15-minute descent, pin-drop silence gripped the Isro control room. The scientists there looked visibly worried but there was no word on what had happened.
- Finally, at 2:18 am, around 40 minutes after Vikram began its descent, Isro chief K Sivan took to a microphone at the control centre and confirmed that contact with Vikram had been lost.
EFFORTS TO GET VIKRAM TALKING AGAIN
In the days since, Isro's focus remained on getting in contact with the Vikram lander. On September 8, Isro said the Chandrayaan-2 orbiter had located Vikram on the lunar surface. Contact with the lander, however, was elusive.
Meanwhile, the US space agency National Aeronautics and Space Administration lent help. Nasa activated its deep space network -- an array of worldwide space antennas -- and began sending signals to the Chandrayaan-2 orbiter and lander. However, while the lander sent signals back, Vikram remained silent.
On September 17, Nasa's Lunar Reconnaissance Orbiter flew over Vikram's landing site and took photos of the lunar surface. Nasa confirmed that orbiter managed to take photos, but indicated that the images were yet to definitively show Vikram.
What hampered the Nasa orbiter from taking sharp pictures was the fact that by the time it flew over Vikram's landing site, it was dusk in the area. Sunlight was steadily fading away, creating long, dark shadows in the crater-filled region and making it difficult to spot Vikram.
By September 21, the south polar region of the Moon where Vikram attempted landing will be enveloped by darkness as night falls in the area. The temperatures will drastically reduce to less than minus 200 degrees Celsius.
Unlike some of the Chinese rovers sent to the Moon, Vikram has no heating apparatus to survive the cold lunar nights. The night will last 14 Earth days by the end of which Vikram will not be in any state of communicate with Earth.
However, clues about its fate may still be forthcoming. The Chandrayaan-2 orbiter is likely to attempt taking more photos of Vikram's landing site once daylight returns to the south polar region. As will the Nasa orbiter that is expected to perform another fly by on October 14.
This, along with Isro's analysis back home may provide clues about what happened to Vikram. There, however, is some indication of what may have happened.
Data and findings collected by the India Today Magazine suggest that during its descent on the Moon, Vikram abruptly and inexplicably turned upside down for a brief moment. During that moment, Vikram's reverse thrust-producing engines located on its belly pointed skyward and pushed the probe down towards the Moon instead of slowing its speed down.
CHANDRAYAAN-2 MISSION CONTINUES
Meanwhile, the Chandrayaan-2 mission will continue with the help of the reinvigorated orbiter. The Chandrayaan-2 orbiter was originally supposed to function for a year. But fuel savings made on the trip to the Moon enabled Isro to extend the orbiter's mission life to seven years.
During these seven years, the Chandrayaan-2 orbiter will perform several experiments. Isro has confirmed that the oribter is functioning well and that all its payloads are powered on. The orbiter has already begun performing experiments.
One of the most crucial experiments the orbiter will perform will be one to carry the Chandrayaan legacy forward. In 2008, the Chandrayaan-1 mission made history by discovering evidence of iced water in the Moon's south polar region. Chandrayaan-2 will take that historic finding forward by trying to estimate the quantity of iced water in the region.
And Vikram? Well, the lander may have gone silent forever. But, it won't be forgotten.