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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CM Siddaramaiah alleges ‘criminal conspiracy’ in Sringeri recount, vows legal action
Bengaluru (PTI): Alleging a “criminal conspiracy” by BJP candidate D N Jeevaraj in the Sringeri Assembly poll recounting, Karnataka CM Siddaramaiah on Tuesday said the outcome was manipulated after valid postal ballot votes in favour of Congress leader T D Raje Gowda were tampered with during the recounting process.
Following a Karnataka High Court order on an election petition filed by Jeevaraj, challenging Raje Gowda’s election, the reverification and recounting were conducted on Saturday.
After the reverification and recount of postal ballots for the Sringeri Assembly constituency, votes polled in favour of Raje Gowda were reduced by 255, the returning officer said.
A report on the matter has been submitted to the Election Commission of India for further action, the officer added.
Congress leader Raje Gowda had won the 2023 Assembly polls from Sringeri by 201 votes, defeating his nearest rival Jeevaraj.
Addressing a press conference in Bengaluru, Siddaramaiah said the High Court had directed the recounting of postal ballots and that irregularities were noticed during the exercise conducted on May 2.
“This is a clear case of criminal conspiracy,” Siddaramaiah said, alleging that valid votes cast in favour of Raje Gowda were altered after being accepted by counting agents of all parties, including Congress, BJP, and JD(S).
He claimed that during the recounting of postal ballots, 255 votes were initially accepted as valid by all agents but were later tampered with by subordinate officials.
“There is a second mark on the votes polled in favour of Raje Gowda. They had accepted these as valid votes. Subsequently, another mark was made by officials. This is a clear case of criminal conspiracy,” he said.
When asked who was behind the alleged conspiracy, the CM replied, “It was hatched by Jeevaraj and others. It is planned.”
Siddaramaiah further alleged that the returning officer acted improperly by declaring the result despite the presence of an Election Commission observer during the recounting.
“Immediately after the counting, the returning officer announced the result. He should not have done so; this is against the law,” he said.
He pointed out that Raje Gowda had originally won by 201 votes, but after the recounting, the BJP candidate was declared the winner by 52 votes.
“The BJP has committed a criminal act of conspiracy. This is not vote chori but vote dacoity,” he alleged.
The CM said a police complaint had already been filed by Raje Gowda’s election agent, Sudhir Kumar, and emphasised the need for electoral integrity.
“We want transparency and free and fair elections. That is what our Constitution mandates,” he added.
Stating that the government would pursue legal remedies, Siddaramaiah said, “We are preparing an appeal challenging the returning officer’s announcement in a court of law.”
Responding to a separate query on elections in other states, the CM said there appeared to be an anti-incumbency factor in West Bengal, while results in Tamil Nadu were “surprising,” adding that Vijay’s party was emerging as the largest there.
Following the victory of party candidates in Bagalkote and Davanagere South, Siddaramaiah expressed confidence about future electoral prospects in Karnataka.
“Even in 2028, we will win the Assembly elections. We will come back,” the CM said.
Siddaramaiah added that he would order a forensic examination into the alleged tampering of postal ballots.
