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Chandrayaan-1

Chandrayaan-1 is the first Indian experimental satellite launched in October, 2008 by Indian Space Research Organisation (ISRO) from Satish Dhawan Space Centre, Sriharikota, Andhra Pradesh, India. In Sanskrit, “Chandrayaan” means Moon Vehicle.

India added itself in the list of select group of nations which undertook lunar missions by sending up its first ever unmanned satellite into the realm of moon. The basic aim of Chandrayaan was to conduct chemical and mineralogical reconnaissance of the entire lunar surface for occurrence of chemical elements such as Magnesium, Aluminium, Silicon, Calcium, Iron and Titanium including high atomic number elements like Radon, Uranium and Thorium with high spatial resolution.

The satellite was successfully launched by the Polar Satellite Launch Vehicle, technically referred to as PSLV-C11 which weighed 1380 kg at the time of launch and 675 kg in the lunar orbit. It was deployed into a transfer orbit with a perigee of 255 km and an apogee of 22,860 km inclined at an angle of 17.9 degrees to the lunar equator.

In addition to its own five payloads, India had rendered free-of-cost service by launching six other payloads pertaining to National Aeronautics and Space Administration (NASA) United States Of America, European Space Agency (ESA) and Bulgarian Aerospace Agency as a magnanimous gesture of extending friendly hand to scientific fraternity. Although the date of launch of Chandrayaan-1 was noted as October 22, 2008 the entire process of actual deployment of the satellite in the intended orbits took 21 days as against the launching it on a direct trajectory.

ISRO had conducted a series of operations for placing Chandrayaan-1 into the final slot of the lunar orbit. Initially, the attempts were to increase in different bouts the size of its elliptical orbits around the earth and subsequently on reaching the proximity range of moon, the size of its elliptical orbits around the moon was to be decreased gradually till the spacecraft reached its intended final slot.  With every increase in apogee and perigee of the orbit around the earth, the revolution period of the satellite went on increasing to 11 hours on October 23; 25 ½ hours on Oct 25; 73 hours on Oct26; and finally 6 days on Oct 29 of 2008. When the apogee was increased to 3,80,000 km the space craft began leaving the elliptical path around the earth and subsequently joined in the elliptical path around the moon with a maximum aposelene (lunar equivalent of apogee) of 7502km and periselene (lunar equivalent of perigee) of 504 km, with a rotating period of 10 ½ hours around the moon. In the next phase of operation, with the gradual decrease in aposelenes and periselenes, the period of spacecraft rotation around moon too decreased accordingly from 10 ½ hours to 2 hours 16 min, 2 hours 9 min, and finally to 2 hours when both the aposelene and periselene were equalised at 100 km.

  • “Mechanical Landing At The Crater SHACKLETON On The Moon”
  • “NASA Appreciated, For Maximum Number Of Clear Images Captured In A Pretty Short Period”

Impact of Moon Impact Probe (MIP) on lunar surface:

At an altitude of 100 km from the lunar surface, the Moon Impact Probe, one of the 11 payloads on board, got separated from Chandrayan-1 and began plummeting on a free fall for 30 minutes.  As it was approaching the moon, the MIP was sending signals to the mother satellite which in turn transmitted to the earth. On 14.11.2008, the Moon Impact Probe touched down on the moon near the crater “Shackleton” at the lunar South Pole. The altimeter which is an instrument to measure altitudes began recording measurements enabling the scientists to prepare for sending the rover to land on lunar surface on their second mission. On successful placement of the MIP, other scientific equipments were switched on to begin for the next phase of the mission.

Chandrayaan-1

Increase In The Temperature Of Spacecraft:

On 25.11.2008, the temperature of Chandrayaan-1 went up beyond the normal level to 50 °C due to upheavals in lunar orbit temperatures caused by solar radiation and lunar reflection of Infra Red radiation. The temperature was deliberately decreased by 10° C by rotating the spacecraft about 20 degrees and turning off some of the instruments. On 27.11.2008, ISRO reported that the spacecraft was functioning under reasonable temperature conditions. However, it was later noticed that the spacecraft was still working under higher temperatures and ISRO stated that the inner machines would be functioning only one at a time till January 2009 when the lunar climatic conditions were expected to get conducive to the spacecraft.

Achievements Of Chandrayaan-1:

  • One of the six non-Indian payloads Moon Mineralogy Mapper (M3) of NASA emphatically upheld the presence of iron bearing minerals such as pyroxene.

“Previous Landing Sites Of NASA Apollo Satellites Were Captured”

  • In January 2009, ISRO declared that as many as six landing sites of Apollo Moon Missions (including the landing sites of Apollo 15 & Apollo 17) were identified using multiple payloads.

  • The orbiter revolved 3000 laps around the moon, clicking 70,000 images of lunar surface so far. The performance of Chandrayaan-1 of sending 40,000 images in 75 days which works out to about 535 images per day is no mean achievement and is quite better than that of any spacecraft sent by other nations, according to ISRO.

  • The excellence of Chandrayaan-1 does not end there. The clarity of the images sent by it is much superior to those sent by other spacecrafts. Some of the images had a resolution down to 5 metres while the images sent by other crafts had a 100 metre resolution.

  • The scientists at ISRO were surprised to find that the lunar surface consisted more craters than peaks as disclosed by the indigenous Terrain Mapping Camera.

  • The X-ray fluorescence phenomenon during an X-ray solar flare showed signals of Aluminium, Magnesium and Silicon.

  • Chandrayaan-1 sent the first images of earth in its totality on 25.3.2009.  

Increase In The Lunar Orbit Of The Spacecraft:

On successful completion of the main objectives, the orbit of the spacecraft was raised from 100 km to 200 km from the lunar surface on 19.5.2009 to study the atmospheric orbit disturbances at higher altitudes, variations in lunar gravitational field and for more integral views of moon surface from greater altitudes.

Presence Of Water:

ISRO tried to detect the presence of water and ice on the moon by performing a bistatic radar experiment using the mini-SAR radars. The attempted resulted in a fiasco as the Chandrayaan-1 radar was not pointed at the moon during the experiment.

On the basis of images showing several permanently shadowed regions existing at both the poles of moon, it was hypothesized by ISRO that more than 40 craters of the moon were filled with water amounting to 6 billion metric tonnes of water ice. However, there were a lot of mutual inconsistencies in the findings of the spacecraft. As of now, the observation by NASA concluded that the presence of small discrete pieces of ice cannot be totally ignored.

End Of The Mission:

The duration of the mission was expected to be two years since its launch on 22.10.2008. Unfortunately, the communication with Chandrayaan-1 was suddenly lost on 28.8.2009 for reasons specifically not fully determined till today making its actual term of performance for 312 days. The mission was expected to last for another 1000 days and the craft was supposed to crash land on the moon surface in late 2012. Although the exact whereabouts of the spacecraft were not known for many days, it was suddenly found to be in its orbit by NASA in 2016.

Awards For Chandrayaan-1 Mission:

In spite of the premature obsolescence of Chandrayaan-1 the following awards have been conferred in view of its numerous achievements and laudable contributions to space science and technology:

  1. International Cooperation Award in 2008 by International Lunar Exploration Working Group for carrying a good number of payloads (both indigenous and others) and conducting fruitful tests in space.

  2. AIAA SPACE award for 2009 by American Institute of Aeronautics and Astronauts.

  3. Space Pioneer Award by US-based National Space Society for the year 2009.

Notwithstanding its premature end of the mission of Chandrayaan-1 taking into consideration its commendable achievements the scientists of ISRO announced that 95% of the main objectives were surprisingly accomplished within the very short time of 312 days during which the satellite was ebulliently responsive to the earth.

Chandrayaan-1

Fillip To Chandrayaan-2:

Greatly encouraged by the performance of Chandrayaan-1, Indian is planning to embark on Chandrayaan-2 mission in the first four months of 2018. As per earlier plans, Russia was to prepare Lander for Chandrayaan-2. Since Roscosmos (Russian Space Federation Agency) was unable to meet the deadline and expressed its inability to make ready the Lander even before the rescheduled date, Indian has decided to make its own Lander and Rover to be launched by Chandrayaan-2.  Lander is intended to detach itself from Chandrayaan-2 in lunar atmosphere (about 100 km from the moon surface just like Chandrayaan-1) for a much smoother landing on moon as against the crash landing of Moon Impact Probe of Chandrayaan-1 and for subsequent release of the wheeled-rover which will make onsite chemical analysis of the soil at different places on the surface.

It is heartening to note that India will be launching Chandrayaan-2 with redoubled enthusiasm into lunar atmosphere for advanced scientific space research with more sophisticated equipment since India has already learnt a lot about the practical difficulties encountered by Chandrayaan-1 in atmospheric thermal upheavals in lunar orbits.

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