In October 2008, ISRO launched the Chandrayaan-1 mission on board a PSLV rocket. There were two payloads, a lunar orbiter and a lunar impactor. The impactor disturbed the surface at the landing site, and collected samples for analysis. The impactor also enabled India to become the fourth country to put its flag on the Moon, after the US, the former Soviet Union and Japan.
The orbiter encountered a series of technical problems, including malfunctions of its star sensors and the thermal shielding. ISRO lost contact to the spacecraft well before the planned mission duration of two years. However, the orbiter still managed to fulfill most of the goals of the mission and even managed to find Ice in the north pole of the Moon.
In March 2017, NASA used new and more precise ground-based radar to track down ISRO’s Chandrayaan-1 orbiter, still going in circles around the Moon. Madhavan Nair, former chairman of the Indian Space Research Organisation hailed NASA for finding the lost spacecraft.
Chandrayaan-2 Overview
India’s second mission to the moon is more advanced than the first. There are three components of the mission, an orbiter, a lander and a rover. The rocket ISRO is planning to use for Chandrayaan-2 is a GSLV MKII and will take off from the space agency’s launch facility at the Sriharikota High Altitude Range (SHAR) in the first few months of 2018.
The orbiter will be deployed at an altitude of 100 kilometers above the surface of the Moon. The lander will then separate from the orbiter, and execute a soft landing on the surface of the Moon, unlike the previous mission which crash landed near the lunar south pole.
ISRO is in the process of testing the actuators and sensors for the soft landing. A rover will then explore the surface. The lander, rover, and orbiter will perform mineralogical and elemental studies of the lunar surface.
The Chandrayaan-2 mission is being tested at an ISRO facility in Chitradurga, Karnataka. Artificial craters have been created for the Lander Sensors Performance Test. Drop tests for the lander and mobility tests for the rover are also being conducted at the facility. The six-wheeled rover is going to be semi-autonomous, and its movements will be partially controlled by ISRO stations on Earth.
The Orbiter
The Orbiter and the Lander will be stacked together and will be injected into an “Earth Parking Orbit”. After going around the Earth several times, the Orbiter will be inserted into an extremely elliptical Lunar orbit, which will be reduced to 100 km over the surface of the moon after a number of orbits.
The orbiter will carry the Lander, with the Rover on board, from Earth orbit to Moon orbit. The orbiter will survey the landing site before deploying the lander.
The primary structure of the orbiter has been constructed, and has been delivered to the integration team in 2015 itself. The integration teams adds in all the components, scientific payloads and sensors to the orbiter.
The actual payloads are an effort that involves many facilities across the nation, and are expected to be integrated in the first quarter of 2017. The interface between the orbiter and the launch vehicle has also been completed.
The Lander
The configuration of the Lander for a soft and safe landing on the Lunar surface has been completed. The payload configuration and the manner in which the Lander will be attached to the Orbiter has been finalised. The lander craft will have a propulsion system on board, which will de-boost the spacecraft during the surface landing.
The lander also has legs, which will deploy during the landing. The legs have been engineered, and drop tests on a single leg conducted. A facility has been established at the Lunar Test Facility in Chitradurga, just for further drop tests of the lander legs.
The lander will have on board a radio altimeter, a pattern detection camera and a laser inertial reference and accelerometer package (LIRAP). These three components have already been tested. A system demonstration module (SDM) for evaluation the propulsion system on the lander, the Lander Actuator Performance TEST (LSPT) and the electrical packages for the Lander are in the advanced stages of realization
The Rover
The Rover is a six wheeled vehicle that will have on board software that will allow it to roam the surface of the moon in a semi-autonomous manner. ISRO will be providing partial command and control instructions from the ground.
The rover has on board a navigation camera, an inclinometer, and a dedicated imager for capturing pictures of the lunar surface.
The three systems have been tested and integrated. The rover will transmit back data from the lunar surface, but there are no plans to actually collect samples of soil, rock or moondust.
The Rover is being tested at a special facility in Bengaluru, where ISRO has created the kind of soft soil with fine particles that is expected to be on the Moon. Tests are underway to evaluate the way in which the wheels of the rover interact with the soil.
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