Orbit of Chandrayaan-2’s lander lowered, one step closer to Moon landing

Agencies
September 3, 2019

New Delhi, Sept 3: The orbit of Chandrayaan-2's landing module 'Vikram' was successfully lowered for the first time on Tuesday and one final manoeuvre remained for India to pull off a historic soft-landing on the moon in the early hours of Saturday.

The 4-second de-orbiting operation was undertaken a day after the indigenously developed lander was separated from Chandrayaan-2's orbiter in a major milestone pushing India's second lunar mission into its last and most crucial leg--a controlled, soft-landing on the Moon.

The propulsion system on-board the lander was fired for the first time to lower its orbit after it started orbiting the moon independently, said the Indian Space Research Organisation(ISRO).

So far, all operations in the journey to the moon were carried out by the main orbiter of the 3,840-kg Chandrayaan-2 spacecraft that was launched into the earth's orbit on July 22 by the country's Geosynchronous Satellite Launch Vehicle, GSLV MkIII-M1.

The ISRO will perform one more de-orbiting manoeuvre on Wednesday, before the powered descent of 'Vikram' on September 7 for its landing in the lunar south pole.

A successful landing will make India the fourth country after Russia, the US and China to achieve a soft landing on the moon. But it will be the first to launch a mission to the unexplored south pole of the Moon.

"The first de-orbiting manoeuvre for Chandrayaan-2 spacecraft was performed successfully today (September 03, 2019) beginning at 0850 hrs IST as planned, using the onboard propulsion system. The duration of the manoeuvre was 4 seconds," the ISRO said giving the latest update on the Rs 978 crore Chandrayaan-2 mission.

"The orbit of 'Vikram' Lander is 104 km x 128 km. Chandrayaan-2 Orbiter continues to orbit the Moon in the existing orbit and both the Orbiter and Lander are healthy," it said, adding that the second and final manoeuvre to further lower the orbit is scheduled on September 4 between 3.30 and 4.30 am IST.

'Vikram' (with rover 'Pragyan' housed inside) is expected to touch down on the surface of the moon on September 7, between 1.30 and 2.30 am.

ISRO Chairman K Sivan has said the proposed soft-landing on the Moon is going to be a "terrifying" moment as it is something the space agency has not done before while the Lunar Orbit Insertion(LOI)manoeuvre was successfully carried out during the previous Chandrayaan-1 mission.

Following the landing, the rover 'Pragyan' will roll out from the lander between 5.30 and 6.30 am on September 7, and carry out experiments on the lunar surface for a period of one lunar day, which is equal to 14 earth days.

The mission life of the lander is also one lunar day, while the orbiter will continue its mission for a year.

Chandrayaan-2 satellite had began its journey towards the moon leaving the earth's orbit in the dark hours on August 14, after a crucial manoeuvre called Trans Lunar Insertion (TLI) that was carried out by ISRO to place the spacecraft on "Lunar Transfer Trajectory." In a major milestone, the spacecraft had successfully entered the lunar orbit on August 20 by performing the LOI operation.

The health of the spacecraft is being continuously monitored from the Mission Operations Complex (MOX) at ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bengaluru with support from Indian Deep Space Network (IDSN) antennas at Bylalu, near Bengaluru, the space agency has said.

The orbiter carries eight scientific payloads for mapping the lunar surface and studying the exosphere (outer atmosphere) of the Moon while the lander carries three scientific payloads to conduct surface and subsurface science experiments.

The rover carries two payloads to enhance the understanding of the lunar surface.

According to the ISRO, the objective of the mission is to develop and demonstrate the key technologies for end-to-end lunar mission capability, including soft-landing and roving on the lunar surface.

On the science front, this mission aims to further expand knowledge about the moon through a detailed study of its topography, mineralogy, surface chemical composition, thermo-physical characteristics and atmosphere, leading to a better understanding of the origin and evolution of the moon, the space agency had said.

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Agencies
July 12,2020

Jaipur/New Delhi, Jul 12: The crisis in Rajasthan Congress has deepened with state Chief Minister Ashok Gehlot and his deputy Sachin Pilot at loggerheads.

While Gehlot is blaming BJP for trying to destabilise the state government by poaching MLAs, Pilot is camping in Delhi to speak to the party leadership regarding the political turmoil in the state.

According to sources, Pilot has sought an appointment with party's interim president Sonia Gandhi but time for the meeting has not yet been given by her. Although Pilot met another party leader to apprise him about the situation in the state and spelled out his grievance.

As of now, many MLAs, who are believed to be in the Pilot camp, are also in Delhi to meet the party leadership. According to sources, the deputy chief minister has the support of nearly 30 Congress MLAs along with many independent legislators.

It is important to note that the controversy broke out in Rajasthan after Special Operation Group (SOG) sent a notice to Sachin Pilot to record his statement in the case registered by SOG in the alleged poaching of Congress MLAs in the state. The clash between Gehlot and Pilot is also over the post of PCC Chief as Gehlot Camp wants that 'One Leader One Post' formula to be implemented in Rajasthan. Currently, Sachin Pilot is heading the PCC besides holding the Deputy CM post.

Sources close to Sachin Pilot have informed that the young leader is upset with the notice issued to him. He believes it is aimed to record his phone calls and keep him under surveillance. Many of Pilot's supporters feel indignation and told Pilot that they cannot work with Ashok Gehlot. Also, Pilot is unlikely to attend the meeting called by Gehlot today, according to sources.

While the top leadership of the party is keeping mum, sources say it is keeping a watch on the development. General Secretary KC Venugopal has taken up the matter of the rift with the party's top brass with them not happy about it.

Rajasthan AICC Incharge Avinash Pandey told media persons: "Everything is under control. Few MLAs had issues and after discussion, they have returned back to Jaipur and others are also in touch. BJP's attempt of destabilising the government will not be successful in Rajasthan and government is stable."

Gehlot also held a meeting with ministers last night in Jaipur.  According to Gehlot camp, the top leadership is apprised of the development of the poaching attempt in the state. Amid Political Crisis Rajasthan CM Ashok Gehlot called a meeting of Ministers and all Cong MLAs tonight at his residence.

The Rajasthan crisis has alerted the other senior leaders of the party who have opined that the Madhya Pradesh incident should not get repeated in Rajasthan.

Former Union Minister and Rajya Sabha MP Kapil Sibbal tweeted, "Worried for our party. Will we wake up only after the horses have bolted from our stables?"

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News Network
May 20,2020

London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.

Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.

In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.

"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.

According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.

They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.

These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.

In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.

The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.

Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.

The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.

"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.

However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.

They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.

This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.

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News Network
July 2,2020

Geneva, Jul 2: The World Health Organization (WHO) has estimated the overall number of coronavirus cases globally at 10,357,662, with 508,055 people having died from the disease.

The UN health agency said in the situation report published on late Wednesday that 163,939 new cases had been recorded in the past day, while further 4,188 patients had died.

Americas continue to lead the count with over 5.2 million cases, followed by Europe with more than 2.7 million.

The WHO declared the COVID-19 outbreak a pandemic on March 11.

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