Knowing About Chandrayaan 2

Credit: ISRO

Chandryaan 2, India's second lunar mission, has been finally launched successfully by ISRO on July 22 with a great hope for scientists and planners and big plethora of questions to common people. India hopes to soft-land a probe on Moon, while also put a satellite around its orbit as endeavours of Chandryaan 2. People are at one hand appreciating the efforts and caliber of Indian scientist specially ISRO and also congratulating the central government for such an endeavor but also question the applicability of such missions except to be in top five or six nations in the space race.  What people of country are going to get out of it is a big question being asked along what another science and technological development will be coming out of this adventure is also a point of discussions.  From a common readers’ point view this article tries to bring some facts and figures about Chandryaan 2 to their knowledge along with some insight into different parts of the device, scientific adventures, its role or expected scientific and technological output etc.

Objectives

  • Chandrayaan 2 attempts to foster a new age of discovery, increase our understanding of space, stimulate the advancement of technology, promote global alliances, and inspire a future generation of explorers and scientists.
  • Chandrayaan 2 is an Indian lunar mission that will boldly go where no country has ever gone before - the Moon's south polar region. Through this effort, the aim is to improve our understanding of the Moon - discoveries that will benefit India and humanity as a whole.
  • Chandrayaan-2 will attempt to soft land the lander -Vikram and rover- Pragyan in a high plain between two craters, Manzinus C and Simpelius N, at a latitude of about 70° south.
  • Evidence for water molecules discovered by Chandrayaan-1, requires further studies on the extent of water molecule distribution on the surface, below the surface and in the tenuous lunar exosphere to address the origin of water on Moon.
  • Extensive mapping of lunar surface to study variations in lunar surface composition is essential to trace back the origin and evolution of the Moon.
  • In addition, South Pole region has craters that are cold traps and contain a fossil record of the early Solar System.
  • Scientific goals include studies of lunar topography, mineralogy, elemental abundance, the lunar exosphere, and signatures of hydroxy land water ice. 
  • The lunar South Pole is especially interesting because of the lunar surface area here that remains in shadow are much larger than that at the North Pole. There is a possibility of the presence of water in permanently shadowed areas around it.
  • The onboard 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.
  • The orbiter will map the lunar surface and help to prepare 3D maps of it.
  • 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.
  • These insights and experiences aim at a paradigm shift in how lunar expeditions are approached for years to come - propelling further voyages into the farthest frontiers.

Design facts about Chandryaan 2

  • A Rs 978-crore project (which includes â‚¹603 crore for space segment and â‚¹375 crore as launch costs)
  • Launch mass -Combined (wet): 3,850 kg; Combined (dry): 1,308kg
  •  Payload mass- Orbiter (wet): 2,379kg , Orbiter (dry): 682kg, Vikram lander (wet): 1,471kg, Vikram lander (dry): 626 kg; Pragyan rover: 27kg.

Different parts of Chandryaan

Along with launching pay loads and vehicles, Chandryaan has three other important parts i.e., Orbiter, Vikram lander and Pragyan rover which have their own significant role in the mission.

Orbiter: The orbiter will orbit the Moon at an altitude of 100 km. The orbiter carries five scientific instruments. Three of them are new, while two others are improved versions of those flown onChandrayaan-1. The approximate launch mass was 2,379kg. 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.  

Dimensions: 3.2 × 5.8 × 2.2 m

Gross lift-off mass: 2,379 kg

Propellant mass: 1,697kg

 Dry mass: 682kg

Power generation capacity: 1000 W

Mission duration: 1 year in lunar orbit, which may be extended to 2 years

Vikram lander: The mission's lander is called Vikram named after Vikram Sarabhai who is widely regarded as the father of the Indian space programme. The Vikram lander will detach from the orbiter and descend to a low lunar orbit of 30 km × 100km using its 800N 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 1,471kg. 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 thrusters for attitude control and five 800 N liquid main engines derived from ISRO's 440 N Liquid Apogee Motor. Initially, the lander design employed four main liquid engines, but a centrallymounted 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 up to 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 tests in late October 2016.

Dimensions: 2.54 × 2 × 1.2 m

Gross lift-off mass: 1,471kg

Propellant mass: 845kg

 Dry mass: 626kg

Power generation capability: 650 W

Mission duration: ≤14 days (one lunar day) 

Pragyan rover: The rover is a 6-wheeled, AI-powered vehicle named Pragyan, which translates to 'wisdom' in Sanskrit. The rover's mass is about 27 kg 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 per second, performing on-site chemical analysis and sending the data to the lander, which will relay it to the Earth station. The expected operating time of Pragyan rover is one lunar day or around 14 Earth days as its electronics are not expected to endure implemented, which could result in longer service time than planned. For navigation the rover uses, the frigid lunar night. However, its power system has a solar-powered 

sleep/wake-up cycle Stereoscopic camera-based 3D vision: two 1 megapixel, monochromatic NAVCAMs in front of the rover will provide the ground control team a 3D view of the surrounding terrain, and help in path-planning by generating a digital elevation model of the terrain.  IIT Kanpur contributed to the development of the subsystems for light-based map generation and motion planning for the rover. Control and motor dynamics: the rover has a rocker-bogie suspension system and six wheels, each driven by independent brushless DC electric motors. Steering is accomplished by differential speed of the wheels or skid steering. Dimensions: 0.9 × 0.75 × 0.85 m

Power: 50 W

Travel speed: 1 cm/sec.

Mission duration: ≤14 days (one lunar day)

Some interesting facts of journey

  • Chandrayaan-2 stack was initially put in an Earth parking orbit of 170 km perigee and 40,400 km apogee by the launch vehicle.
  •  It is currently performing orbit-raising operations followed by trans-lunar injection using its own power.
  • The next orbit-raising manoeuvre is planned on August 6 
  • The landing is expected to happen on September 7 
  • The orbiter will perform mapping from an altitude of 100 kilometers (62 miles), while the lander will make a soft landing on the surface and send out the rover.

Achievements so far

  • All post-launch activities have been successful 
  • ISRO has released first images on August 3 taken by the LI4 camera on Vikram, the lander on Chandrayaan-2

 

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