ISRO moves Chandrayaan-3 propulsion module to orbit around Earth in unique experiment
Bengaluru (PTI): The Propulsion Module (PM) of Chandrayaan-3 has been moved from an orbit around the Moon to an orbit around Earth, ISRO has said, terming the operation a unique experiment.
The primary objective of the Chandrayaan-3 mission was to demonstrate a soft landing near the lunar south polar region and perform experiments using the instruments on the 'Vikram' lander and the 'Pragyan' rover.
The spacecraft was launched on July 14, 2023, on board the LVM3-M4 vehicle from the Satish Dhawan Space Centre (SDSC-SHAR).
On August 23, the Vikram lander made its historic touchdown on the Moon and subsequently, the Pragyan rover was deployed.
The scientific instruments in the lander and rover were operated continuously for one lunar day as per the defined mission life.
"The mission objectives of Chandrayaan-3 have been completely met," the Indian Space Research Organisation (ISRO) said in a statement.
For the Propulsion Module, the main objective was to ferry the lander module from the Geostationary Transfer Orbit (GTO) to the final lunar polar circular orbit and separate the lander, it said.
After the separation, the Spectro-polarimetry of HAbitable Planet Earth (SHAPE) payload in the PM was also operated, the space agency said.
The initial plan was to operate this payload for about three months during the mission life of the PM. The precise orbit injection by LVM3 and optimal earth or lunar burn manoeuvres resulted in the availability of over 100 kg of fuel in the PM after over one month of operations in the lunar orbit, it added.
ISRO said that it was decided to use the available fuel in the PM to derive additional information for future lunar missions and demonstrate the mission operation strategies for a sample return mission.
To continue the SHAPE payload for earth observation, it was decided to re-orbit the PM to a suitable earth orbit. This mission plan was worked out considering collision avoidance such as preventing the PM from crashing onto the Moon's surface or entering into the Earth's Geosynchronous Equatorial Orbit (GEO) belt at 36,000 km and orbits below that, the statement said.
Considering the estimated fuel availability and the safety of the GEO spacecraft, the optimal earth return trajectory was designed for October 2023.
The first maneuver was performed on October 9, 2023, to raise apolune altitude to 5,112 km from 150 km thus increasing the period of orbit from 2.1 hours to 7.2 hours. Later, considering the estimate of available propellant, the second manoeuvre plan was revised to target an Earth orbit of 1.8 lakh x 3.8 lakh km.
The Trans-Earthinjection (TEI) maneuver was performed on October 13, 2023. In the post-TEI manoeuvre realised orbit, the PM made four Moon fly-bys before departing the sphere of influence (SOI) of the Moon on November 10.
Currently, the PM is orbiting Earth and crossed its first perigee on November 22 with an altitude of 1.54 lakh km. The orbit period is nearly 13 days with a 27-degree inclination. The perigee and apogee altitude vary during its trajectory and the predicted minimum perigee altitude is 1.15 lakh km, ISRO said.
"Hence as per current orbit prediction, there is no threat of close approach with any operational Earth-orbiting satellites," it said.
As per the plan, the SHAPE payload is being operated whenever Earth is in its field of view. Also, a special operation of the SHAPE payload was carried out on October 28, 2023, during a solar eclipse. The SHAPE payload operations will continue further, the statement added.
"UR Rao Satellite Centre/ISRO's flight dynamics team has developed an analysis tool from first principles for this operation which is being validated through the return maneuvers carried out for the Chandrayaan-3 PM," ISRO said.
According to ISRO, the following are the main outcomes of the return manoeuvres carried out on the PM related to future missions: Planning and execution of trajectory and manoeuvres to return from the Moon to Earth; development of a software module to plan such a manoeuvre and its preliminary validation; planning and execution of a gravity-assisted fly-by across a planet or celestial body; and avoiding uncontrolled crashing of the PM onto the Moon's surface at the end of life of the PM thus meeting the requirements of no debris creation.
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Kangana Ranaut shown black flags in Himachal's Lahaul and Spiti, BJP files complaint with CEO
Shimla, May 20: Actor Kangana Ranaut, BJP candidate from the Mandi parliamentary constituency, was shown black flags by local people and Congress workers at Kaza in Lahaul and Spiti on Monday.
The Himachal Pradesh BJP filed a complaint with the state chief electoral officer (CEO) demanding transfer of election officials and an investigation into the incident as both the BJP and the Congress were given permission to hold rallies adjacent to each other.
The Congress workers raised anti-Kangana slogans - "Kangana, go back, Kangana Vangana nahi chalegi". They were apparently enraged over her remarks on Tibetan spiritual leader Dalai Lama in April last year.
Ranaut had tweeted a meme featuring the Dalai Lama that said, "The Dalai Lama receives a warm welcome at the White house". The photoshopped picture in the tweet showed the Dalai Lama sticking his tongue out with US President Joe Biden with a comment - Both of them have the same illness, definitely they could be friends.
Following this, a group of Buddhists staged a dharna outside her office in Mumbai.
Later she apologised saying she didn't mean to hurt anyone, and it was a harmless joke about Biden being friends with the Dalai Lama.
Leader of the Opposition in the Himachal Pradesh Assembly Jai Ram Thakur, who had accompanied Ranaut to Kaza to campaign for the BJP, on Monday alleged that the Congress workers tried to disturb the meeting of the BJP and pelted stones on their carcade while they were returning.
Talking to reporters, he said, "It is unfortunate that for the first time, permission was given to hold a parallel rally at the venue to the Congress where prior permission was already granted to the BJP to hold the rally.
Efforts were made to disturb our rally and the Congress workers raised shameful slogans, stopped our carcade and pelted stones, injuring one person."
Thakur added that they go for campaigning all over the state but such things have happened for the first time, which shows "frustration" of the Congress and they would take up the issue with the Election Commission.
Later, in a complaint filed with the Himachal Pradesh CEO, BJP state office secretary Parmod Kumar Thakur said the Congress workers allegedly tried to illegally restrain the political procession and even pelted stones and demanded an investigation into the incident.
"The district administration granted permission for organising a political meeting to the Congress adjacent to the place already scheduled to hold a political meeting of the BJP at Kaza under undue influence of the state government in utter violation of the Model Code of Conduct (MCC)", he said.
In the complaint, the BJP demanded the immediate transfer of election officials from Lahaul and Spiti and said giving permission to both the parties at the same location at the same time was a "big lapse" on the part of the Election Commission "in spite of the fact that permission to the BJP was provided first and the officers involved in this act are biased against the BJP, and free and fair elections are doubtful under the circumstances."
Lahaul and Spiti SP Mayank Chowdhary told PTI that workers of both the BJP and the ruling Congress came face to face but there was no clash and no person was injured. However, one worker sprained his leg, he added.
Bhishan Shashni, Congress election coordinator for Lahaul and Spiti claimed that the Congress workers were peacefully protesting but a large number of people, who were hurt by Ranaut's remarks about the Tibetan spiritual leader, joined the protest.
Earlier, Congress candidate from the Mandi Lok Sabha seat Vikramaditya Singh had asked why Ranaut did not visit Spiti and returned from Reckong Peo alleging that she was afraid she would be shown black flags for her remarks against the Dalai Lama.
