Monday, 5 August 2019

CHANDRAYAAN - 2


 INTRODUCTION:

Chandrayaan 2 is India’s second lunar exploration mission after Chandrayaan 1. Developed by the Indian space research organisation (ISRO), the mission was launched from the second launch pad at Satish Dhawan Space Centre on 22nd July 2019 at 2:43 P.M.  IST (09:13 UTC) to the moon by Geosynchronous Satellite Launch Vehicle Mark III (GSLV Mk-III). The planned  orbit has a very perigee of 169.7 km and an apogee of 45475 km. It consists of a lunar orbiter, lander and rover, all developed in India. The main scientific objective is to map the location and abundance of lunar water.

The lander and the rover will land near lunar south pole in a high plane between two craters, Manzinus C and Simpelius N, at a latitude of about 70 degree south on 7th September, 2019 . The wheeled rover will move on the lunar surface and will perform on – site chemical analyses for a period of 14 days (1 Lunar Day). It can relay data to earth through the chandrayaan -2 orbiter and  lander, which will fly on the same lauch. The orbiter will keep working on its mission  for  1 year in a circularized lunar polar orbit of 100*100 km.

Launch of Chandrayaan 2 was originally scheduled for 14 July 2019 at 21:21 UTC (15 July 2019 2:51 IST) but was called off due to technical snag notice around 56 minutes before launch. It was launched on 22 July 2019 14:43 IST (09:13 UTC) from the Salish Dawan Space Centre at Sriharikota in Nellore district of Andhra Pradesh.

A successful landing would make India the 4th country to achieve a soft landing on the moon after the space agency of the USSR, US and CHINA. If successful, chandrayaan 2 will be the southernmost lunar landing, aiming to land at 67 degree South or 70 degree south latitude.

HISTORY:
On 12th November 2007, representatives of the Russian Federal Space Agency (Roscomos) and ISRO signed an agreement for the two agencies to work together on the Chandrayaan-2 projects. ISRO would have the prime responsibility for the orbiter and rover, while Roscosmos was to provide the lander. The Indian government approved the mission in a meeting of the Union Cabinet, held on 18 September 2008 and chaired by Prime Minister Manmohan Singh. The design of the spacecraft was completed in August 2009, with scientists of both countries conducting a joint review.

Although ISRO finalised the payload for Chandrayaan-2 per schedule, the mission was postponed in January 2013 and rescheduled to 2016 because Russia was unable to develop the lander on time. Roscosmos later withdrew in wake of the failure of the Fobos-Grunt mission to Mars, since the technical aspects connected with the Fobos-Grunt mission were also used in the lunar projects, which needed to be reviewed. When Russia cited its inability to provide the Lander even by 2015, India decided to develop the lunar mission independently.

The spacecraft’s launched had been scheduled for March 2018, but was first delayed to April and then to October to conduct further tests on the vehicle. On 19 June 2018, after the program’s fourth Comprehensive Technical Review meeting, a number of changes in configuration and landing sequence were planned for implementation, pushing the launch to the first half of 2019. Two of the lander’s legs got minor damage during one of the tests in February 2019.

Chandrayaan-2 launch was initially schedule for 14 July 2019, 21:21 UTC (15 July 2019 at  02:51 IST local time),with the landing expected on 6 September 2019. However, the launch was aborted due to a technical glitch and rescheduled to 22 July 2019.

The technical glitch was later clarified to be a leak in the 'nipple joint' of the helium gas bottle. The leak was not serious enough to impair the mission, however "abundant caution" was exercised due to the importance of the mission. It is speculated that the leak might have been caused due to the micro-shrinkage of the joint which could occur at low temperature. The proximity of the 'nipple joint' to the oxidiser tank, which contains liquid oxygen at -183°C, could have induced such a low temperature. Chandrayaan-2 was successfully launched on board by the GSLVMk-III M1 launch vehicle on 22 July 2019 at 09:13 UTC (14:43IST).
  
 OBJECTIVES:

The primary objectives of Chandrayaan-2 are to demonstrate the ability to soft-land on the lunar surface and operate a robotic rover on the surface. Scientific goals include studies of lunar topography, mineralogy, elemental abundance, the lunar exosphere, and signatures of hydroxyl and water ice. The orbiter will map the lunar surface and help to prepare 3D maps of it. The on board radar will also map the surface while studying the water ice in the south polar region and thickness of the lunar regolith on the surface. Chandrayaan-2 will in form the location and Abundance of lunar water for exploitation by the future lunar base proposed by the Artemis program.




DESIGN:

The mission is planned to fly on a Geosynchronous Satellite Launch Vehicle MarkIII (GSLVMk III) with an approximate lift-off mass of 3,850 kg (8,490 lb) from Satish Dhawan Space Centre on Sriharikota Island. As of June 2019, the mission has an allocated cost of Rs 978 crore (approximately US $141 million) which includes 603 crore for space segment and 375 crore as launch costs on GSLVMk-III. Chandrayaan-2 stack would be initially put in an Earth parking orbit of 170 km perigee and 40,400 km apogee by the launch vehicle. It will then perform orbit-raising operations followed by trans-lunar injection using it's own power.

 ORBITER:


The orbiter will orbit the Moon at an altitude of 100 km (62 mi). The orbiter carries five scientific instruments. Three of them are new, while two others are improved versions of those flown on Chandrayaan-1. The approximate launch mass will be 2,379 kg (5,245 lb). The Orbiter High Resolution Camera (OHRC) will conduct high-resolution observations of the landing site prior to separation of the lander from the orbiter. The orbiter's structure was manufactured by Hindustan Aeronautics Limited and delivered to ISRO Satellite Centre on 22 June 2015.  

VIKRAM LANDER:

The mission's lander is called Vikram named after Vikram Sarabhai (1919–1971), who is widely regarded as the father of the Indian space programme.

The Vikram lander will detach from the orbiter and descend to a lunar orbit of 30 km×100 km (19 mi×62 mi) using its 800 N (180 lbf) liquid main engines. It will then perform a comprehensive check of all its on-board systems before attempting a soft landing, deploy the rover, and perform scientific activities for approximately 14 days. The approximate combined  mass of the lander and rover is 1,471 kg (3,243 lb).

The preliminary configuration study of the lander was completed in 2013 by the Space Applications Centre (SAC) in Ahmedabad. The lander's propulsion system consists of eight 50 N (11 lbf) thrusters for attitude control and five 800 N (180 lbf) liquid main engines derived from ISRO's 440 N (99 lbf) Liquid Apogee Motor. Initially, the lander design employed four main liquid engines, but a centrally mounted engine was added to handle new requirements of having to orbit the Moon before landing. The additional engine is expected to mitigate upward draft of lunar dust during the soft landing. Vikram can safely land on slopes upto 12°.

Some associated technologies include a high resolution camera, Lander Hazard Detection Avoidance Camera (LHDAC), Lander Position Detection Camera (LPDC), an 800 N throttleable liquid main engine, attitude thrusters, Ka band radio altimeter (KaRA), Laser Inertial Reference & Accelerometer Package (LIRAP), and the software needed to run these components. Engineering models of the lander began undergoing ground and aerial test’s in late October 2016, in Challakere in the Chitradurga district of Karnataka. ISRO created roughly 10 craters on the surface to help assess the ability of the lander's sensors to select a landing site.

Dimensions: 2.54×2×1.2m
Gross lift-off mass: 1,471 kg (3,243 lb)
Propellant mass: 845 kg (1,863 lb)
Drymass: 626 kg(1,380 lb)
Power generation capability: 650 W

PRAGYAN ROVER: 

The mission's rover is called PragyanThe rover's mass is about 27 kg (60 lb) and will operate on solar power. The rover will move on 6 wheels traversing 500 meters on the lunar surface at the rate of 1 cm\sec, performing on-site chemical analysis and sending the data to the lander, which will relay it to the Earth station.
     

SUBMITTED BY:

SHYAMA DINESHAN
SUSHMITHA  K
SUSHMITHA M
VEEKSHITH P
YOGISHA K 
TEJA


Reference: Journal
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