Vikram undergoes de-orbit manoeuvre
- Vikram now goes around in a slightly shorter orbit at a distance of 104 km x 128 km from the moon.
- On 2 September 2019 afternoon, Vikram, carrying a rover within, broke free as planned from atop the main Chandrayaan-2 spacecraft (which continues to orbit the moon on its own.)
- The first de-orbiting manoeuvre was performed successfully on September 03 beginning at 0850 hrs IST as planned using the on board propulsion system. Both the orbiter and the lander are healthy.
- The next orbit-cutting manoeuvre is marked for September 4 between 3.30 and 4.30 a.m.
- ISRO has already decided on the landing zone for Vikram on the 7th September landing. Vikram is expected to land between two craters called Manzinus C and Simpelius N at a latitude of around 70.9 degrees South and 22.7 degrees East.
- Just in case, if Vikram finds it difficult to make an approach to this landing site, then it can look for an alternative site which is 67.7 degrees South and 18.4 degrees West.
- However, one of the most important sensor on-board of Orbiter from the Vikram’s point of view is the Orbiter High-Resolution Camera (OHRC).
- This sensor would be providing high-resolution images of the landing site for ensuring the Vikram’s safe touchdown. Already Vikram must have got some inputs about the possibility of any craters or boulders around the landing site.
- A Digital Elevation Model (DEM) of the landing site would be generated based on the OHRC data. This would assist Vikram for landing on the D-day.
- OHRC’s images will be captured over the course of two orbits, covering an area of 12 km x 3 km. The ground resolution of the OHRC’s imagery is 0.32 m.
- The travel-time for Chandrayaan-2 from the launch date to the soft landing is going to be 48 days in total. It is a very long journey and by 02 September Chandrayaan-2 has successfully completed 42 to 43 days of journey.
- For Vikram and Pragyan, this journey was not a major challenge (in a relative sense) because they were safely placed inside the womb of the orbiter.
- The Orbiter was required to take care of its own health because it’s travel towards the Moon was full of atmospheric resistance which was a worry for aerodynamics.
- The spacecraft must have experienced various external forces including gravitational force (since everything with a mass exerts this force), forces brought in by solar winds and forces occurring due to the change in the velocity of the spacecraft.