Chandrayaan-1 (; from Sanskrit: , "Moon" and , "craft, vehicle") of the Chandrayaan programme, was the first Indian lunar probe. It was launched by ISRO in October 2008, and operated until August 2009. The mission consisted of an orbiter and an impactor. ISRO launched the spacecraft using a PSLV-XL (C-11) rocket on 22 October 2008 at 00:52 UTC from Satish Dhawan Space Centre (SDSC), at Sriharikota, Andhra Pradesh. The mission was a major boost to India's space program, as India researched and developed its own technology to explore the Moon. The vehicle was inserted into lunar orbit on 8 November 2008.
On 14 November 2008, the Moon Impact Probe separated from the Chandrayaan orbiter at 14:36 UTC and struck the south pole in a controlled manner. The probe hit near the crater Shackleton at 15:01 UTC. The location of the impact was named Jawahar Point. With this mission, ISRO became the fifth national space agency to reach the lunar surface. Other nations whose national space agencies achieved similar feats were the former Soviet Union in 1959, the United States in 1962, Japan in 1993, and European Space Agency member states in 2006.
The estimated cost for the project was . It was intended to survey the lunar surface for over two years, to produce a complete map of the chemical composition at the surface and its three-dimensional topography. The polar regions were of special interest as there was a high chance of finding water ice. One of its many achievements was the discovery of the widespread presence of water molecules in lunar soil.
After almost a year, the orbiter started experiencing several technical issues including failure of the star tracker and poor thermal shielding; Chandrayaan-1 stopped communicating at about 20:00 UTC on 28 August 2009, shortly after which the ISRO officially declared that the mission was over. Chandrayaan-1 operated for 312 days as opposed to the intended two years; however, the mission achieved most of its scientific objectives, including detecting the presence of Lunar water.
On 2 July 2016, NASA used ground-based radar systems to relocate Chandrayaan-1 in its lunar orbit, almost seven years after it shut down. Repeated observations over the next three months allowed a precise determination of its orbit which varies between in altitude every two years.
History Former Prime Minister of India, Atal Bihari Vajpayee, announced the Chandrayaan 1 project The mission was a major boost to India's space program. The idea of an Indian scientific mission to the Moon was first raised in 1999 during a meeting of the Indian Academy of Sciences. The Astronautical Society of India (ASI) began planning the implementation of such an idea in 2000. Soon after, the Indian Space Research Organisation (ISRO) set up the National Lunar Mission Task Force. The Task Force decided that the ISRO had the technical expertise to carry out an Indian mission to the Moon. In April 2003, over 100 Indian scientists spanning fields from planetary science, space sciences, Earth sciences, physics, chemistry, astronomy, astrophysics, engineering, and communication sciences discussed and approved the Task Force recommendation to launch an Indian probe to the Moon. Six months later, in November, the Vajpayee government formally approved the mission.
Objectives The mission had the following objectives:
To design, develop, launch, and orbit a spacecraft around the Moon using an Indian-made launch vehicle To conduct scientific experiments using instruments on the spacecraft which would yield data: for the preparation of a three-dimensional atlas (with high spatial and altitude resolution of ) of both the near and far sides of the Moon for chemical and mineralogical mapping of the entire lunar surface at a high spatial resolution, mapping particularly the chemical elements magnesium, aluminum, silicon, calcium, iron, titanium, radon, uranium, and thorium To increase scientific knowledge To test the impact of a sub-satellite (Moon Impact Probe – MIP) on the surface of the Moon as a forerunner for future soft-landing missions
Goals To reach its objective, the mission defined these goals:
High-resolution mineralogical and chemical imaging of the permanently shadowed north- and south-polar regions To search for surface or subsurface lunar water ice, especially at the lunar poles Identification of chemicals in lunar highland rocks Chemical stratigraphy of the lunar crust by remote sensing of the central uplands of large lunar craters, and of the South Pole Aitken Region (SPAR), an expected site of interior material Mapping the height variation of features of the lunar surface Observation of X-ray spectrum greater than 10 keV and stereographic coverage of most of the Moon's surface with resolution
Specifications
Mass at launch, at lunar orbit, and after releasing the impactor. Dimensions Cuboid in shape of approximately Communications X band, diameter dual gimballed parabolic antenna for payload data transmission. The Telemetry, Tracking & Command (TTC) communication operated in S band frequency. Power The spacecraft was mainly powered by its solar array, which included one solar panel covering a total area of generating 750 W of peak power, which was stored in a 36 Ampere-hour(A·h) lithium-ion battery for use during eclipses. Propulsion The spacecraft used a bipropellant integrated propulsion system to reach lunar orbit as well as orbit and altitude maintenance while orbiting the Moon. The power plant consisted of one 440 Newton(N) engine and eight 22 N thrusters. Fuel and oxidizer were stored in two tanks of each. Navigation and control The craft was 3-axis stabilized with two star sensors, gyros, and four reaction wheels. The spacecraft carried dual redundant bus management units for attitude control, sensor processing, antenna orientation, etc.
Payload The scientific payload had a mass of . The payload contained five Indian instruments and six instruments from other countries.
Indian instruments TMC or the Terrain Mapping Camera was a CMOS camera with resolution and a swath in the panchromatic band and was used to produce a high-resolution map of the Moon. This instrument aimed to completely map the topography of the Moon. The camera works in the visible region of the electromagnetic spectrum and captures black-and-white stereo images. When used in conjunction with data from the Lunar Laser Ranging Instrument (LLRI), it can help in a better understanding of the lunar gravitational field as well. TMC was built by the ISRO's Space Applications Centre (SAC) at Ahmedabad. The TMC was tested on 29 October 2008 through a set of commands issued from ISTRAC. HySI or Hyper Spectral Imager is a CMOS camera, that performs mineralogical mapping in the 400–900 nm band with a spectral resolution of 15 nm and a spatial resolution of . LLRI or Lunar Laser Ranging Instrument determines the height of the surface topography by sending pulses of infrared laser light toward the lunar surface and detecting the reflected portion of that light. It operated continuously and collected 10 measurements per second on both the day and night sides of the Moon. LLRI was developed by the Laboratory for Electro-Optics Systems of ISRO, Bangalore. It was tested on 16 November 2008. HEX is a High Energy aj/gamma x-ray spectrometer for 30–200 keV measurements with a ground resolution of , the HEX measured Uranium, Thorium, Lead-210, Radon-222 degassing, and other radioactive elements. MIP was developed by the ISRO is an impact probe that consists of a C-band Radar altimeter for measurement of the altitude of the probe, a video imaging system for acquiring images of the lunar surface, and a mass spectrometer for measuring the constituents of the lunar atmosphere. It was ejected at 14:30 UTC on 14 November 2008. As planned, the Moon Impact Probe impacted the lunar south pole at 15:01 UTC on 14 November 2008. ISRO was the fifth national space agency to reach the surface of the Moon. Other national space agencies to have done so prior were the former Soviet Union in 1959, the United States in 1962, Japan in 1993, and ESA in 2006.
Instruments from other countries
These international contributions were vital to the mission’s success and overall achievements of Chandrayaan 1. C1XS or X-ray fluorescence spectrometer covering 1–10 keV, mapped the abundance of Magnesium, Aluminium, Silicon, Calcium, Titanium, and Iron at the surface with a ground resolution of , and monitored solar flux. This payload results from the collaboration between the Rutherford Appleton Laboratory, United Kingdom, European Space Agency (ESA) and ISRO. It was activated on 23 November 2008. SARA, the Sub-keV Atom Reflecting Analyser from the ESA mapped mineral composition using low energy neutral atoms emitted from the surface. M3, the Moon Mineralogy Mapper from Brown University and Jet Propulsion Laboratory (JPL, funded by NASA) was an imaging spectrometer designed to map the surface mineral composition. It was activated on 17 December 2008. SIR-2, a near-infrared spectrometer from ESA, was built at the Max Planck Institute for Solar System Research, Polish Academy of Sciences, and University of Bergen. SIR-2 mapped the mineral composition using an infrared grating spectrometer. The instrument is similar to that of the Smart-1 SIR. It was activated on 19 November 2008 and scientific observations were started on 20 November 2008. Mini-SAR, designed, built, and tested for NASA by a large team that includes the Naval Air Warfare Center, Johns Hopkins University Applied Physics Laboratory, Sandia National Laboratories, Raytheon, and Northrop Grumman, with outer support from ISRO. Mini-SAR is the active Synthetic Aperture Radar system to search for lunar polar ice and water ice. The instrument transmitted right polarised radiation with a frequency of 2.5 GHz and monitored scattered left and right polarised radiation. The Fresnel reflectivity and the circular polarisation ratio (CPR) are the key parameters deduced from these measurements. Ice shows the Coherent Backscatter Opposition Effect, which results in an enhancement of reflections and CPR so that the water content of the Moon's polar regions can be estimated. RADOM-7, Radiation Dose Monitor Experiment from the Bulgarian Academy of Sciences mapped the radiation environment around the Moon. It was tested on 16 November 2008.
Mission timeline
During the tenure of Prime Minister Manmohan Singh, the Chandrayaan project got a boost and finally Chandrayaan-1 was launched on 22 October 2008 at 00:52 UTC from Satish Dhawan Space Centre using the ISRO's tall, four-stage PSLV C11 launch vehicle. Chandrayaan-1 was sent to the Moon in a series of orbit-increasing manoeuvres around the Earth over a period of 21 days as opposed to launching the craft on a direct trajectory to the Moon. At launch the spacecraft was inserted into geostationary transfer orbit (GTO) with an apogee of and a perigee of . The apogee was increased with a series of five orbit burns conducted over a period of 13 days after launch.
For the duration of the mission, ISRO's telemetry, tracking and command network (ISTRAC) at Peenya in Bangalore, tracked and controlled Chandrayaan-1. Scientists from India, Europe, and the U.S. conducted a high-level review of Chandrayaan-1 on 29 January 2009 after the spacecraft completed its first 100 days in space.
Earth orbit burns + Earth orbit burns Date (UTC) Burn time(minutes) Resulting apogee 22 OctoberLaunch 18.2in four stages 22,860 km 23 October 18 37,900 km 25 October 16 74,715 km 26 October 9.5 164,600 km 29 October 3 267,000 km 4 November 2.5 380,000 km First orbit burn