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The Spacecraft - Description. Spacecraft for lunar mission is : Cuboid in shape of approximately 1.50 m side. Weighing 1304 kg at launch & 590 kg at lunar orbit. Accommodates eleven science payloads. 3-axis stabilized spacecraft using two star sensors, gyros & four reaction wheels. The power generation would be through a canted single-sided solar array to provide required power during all phases of the mission. This deployable solar array consisting of a single panel generates 700W of peak power. Solar array along with yoke would be stowed on the south deck of the spacecraft in the launch phase. During eclipse spacecraft will be powered by Lithium ion (Li-Ion) batteries. After deployment the solar panel plane is canted by 30º to the spacecraft pitch axis. The spacecraft employs a X-band, 0.7m diameter parabolic antenna for payload data transmission. The antenna employs a dual gimbal mechanism to track the earth station when the spacecraft is in lunar orbit. The spacecraft uses a bipropellant integrated propulsion system to reach lunar orbit as well as orbit & attitude maintenance while orbiting the moon. The propulsion system carries required propellant for a mission life of 2 years, with adequate margin. The Telemetry, Tracking & Command (TTC) communication is in S-band frequency. The scientific payload data transmission is in X-band frequency. The spacecraft has three Solid State Recorders (SSRs) on board to record data from various payloads. SSR-1 will store science payload data & has capability of storing 32Gb data. SSR-2 will store science payload data along with spacecraft attitude information (gyro & star sensor), satellite house keeping & other auxiliary data. The storing capacity of SSR-2 is 8Gb. M3 (Moon Mineralogy Mapper) payload has an independent SSR with 10Gb capacity.

GROUND SEGMENT FOR CHANDRAYAAN-1 MISSION

Ground Segment for Chandrayaan-1 comprises three major elements viz. Deep Space Station (DSN), Spacecraft Control Center (SCC) & Indian Space Science Data Center (ISSDC). This trio of ground facility ensures the success of the mission by providing to & fro conduit of communication, securing good health of the spacecraft, maintaining the orbit & attitude to the requirements of the mission & conducting payload operations.The ground segment is also responsible for making the science data available for the Technologists / Scientists along with auxiliary information, in addition to storage of payload & spacecraft data.

Ground Segment for Chandrayaan-1

• The Terrain Mapping Camera (TMC) has 5 m resolution & a 40 km swath in the panchromatic band & will be used to produce a high-resolution map of the Moon.

• The Hyper Spectral Imager (HySI) will perform mineralogical mapping in the 400-900 nm band with a spectral resolution of 15 nm & a spatial resolution of 80 m.

• The Lunar Laser Ranging Instrument (LLRI) will determine the surface topography.

• An X-ray fluorescence spectrometer C1XS covering 1- 10 keV with a ground resolution of 25 km & a Solar X-ray Monitor (XSM) to detect solar flux in the 1–10 keV range. C1XS will be used to map the abundance of Mg, Al, Si, Ca, Ti, & Fe at the surface, & will monitor the solar flux. This payload is a collaboration between Rutherford Appleton laboratory, U.K, ESA & ISRO.

• A High Energy X-ray/gamma ray spectrometer (HEX) for 30- 200 keV measurements with ground resolution of 40 km, the HEX will measure U, Th, ²¹⁰Pb, ²²²Rn degassing, & other radioactive elements
• Moon Impact probe(MIP) developed by ISRO is in turn a small satellite that will be carried by Chandrayaan-1 & will be ejected once it reaches 100 km orbit around moon, to impact on the moon. MIP carries three more instruments namely, a high resolution mass spectrometer, an S-Band altimeter & a video camera. The MIP also carries with it a picture of the Indian flag, it's presence marking as only the fourth nation to place a flag on the moon after Russia, United States & Japan.

• Among foreign payloads, The Sub-keV Atom Reflecting Analyzer (SARA) from ESA will map composition using low energy neutral atoms sputtered from the surface.

• The Moon Mineralogy Mapper (M3) from Brown University & JPL (funded by NASA) is an imaging spectrometer designed to map the surface mineral composition.

• A near infrared spectrometer (SIR-2) from ESA, built at the Max Planck Institute for Solar System Research, Polish Academy of Science & University of Bergen, will also map the mineral composition using an infrared grating spectrometer. The instrument will be similar to that of the Smart-1 SIR.

• S-band miniSAR from the APL at the Johns Hopkins University (funded by NASA) is the active SAR system to map lunar polar ice. The instrument will transmit right polarized radiation with a frequency of 2.5 GHz & will monitor the scattered left & right polarized radiation. The Fresnel reflectivity & the cicular polarization ratio (CPR) are the key parameters deduced from this measurments. Ice shows the Coherent Backscatter Opposition Effect which results in an enhancement of refelections & CPR. With the data the water content of the moon polar region can estimated.

• Radiation Dose Monitor (RADOM-7) from Bulgaria is to map the radiation environment around the moon.

Launch Vehicle - Polar Satellite Launch Vehicle The Indian Space Research Organisation (ISRO) built its Polar Satellite Launch Vehicle (PSLV) in the early 90s. The 45 m tall PSLV with a lift-off mass of 295 tonne, had its maiden success on October 15, 1994 when it launched India's IRS-P2 remote sensing satellite into a Polar Sun Synchronous Orbit (SSO) of 820 km. Between 1996 & 2005, it has launched six more Indian Remote Sensing satellites as well as HAMSAT, a micro satellite built by ISRO for amateur radio communications into polar SSOs, one Indian meteorological satellite into Geosynchronous Transfer Orbit (GTO). During this period, PSLV has also launched four satellites from abroad (TUBSAT & DLR-Bird from Germany, Proba from Belgium & KITSAT from Republic of Korea) as piggyback payloads into polar SSOs. Thus, PSLV has emerged as ISRO's workhorse launch vehicle & proved its reliability & versatility by scoring eight consecutive successes between 1994-2005 periods in launching multiple payloads to both SSO as well as GTO. The first Indian moon mission is proposed to be a lunar polar orbiter at an altitude of about 100 km from the lunar surface. Considering the maturity of Polar Satellite Launch Vehicle (PSLV) demonstrated through PSLV-C4/KALPANA-1 mission, PSLV is chosen for the first lunar mission. The upgraded version of PSLV viz., PSLV-C11 which has a liftoff weight of 316 tonnes, will be used to inject 1304 kg mass spacecraft at 240 x 24,000 km orbit & the corresponding spacecraft mass is 590kg when the target lunar orbit of 100 km is achieved. Participating Groups The following ISRO Centres are participating in the Chandrayaan Mission -1 1. ISRO Headquarters, Bangalore, India 2. ISRO Satellite Centre (ISAC), Bangalore, India 3. Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, India 4. Space Application Centre (SAC), Ahmedabad, India 5. ISRO Telemetry , Tracking & Command Network (ISTRAC), Bangalore, India 6. Laboratory for Electro Optic Systems (LEOS), Bangalore, India 7. Physical Research Laboratory (PRL), Ahmedabad, India 8. Space Physics Laboratory (SPL), VSSC, Thiruvananthapuram, India 9. National Remote Sensing Agency (NRSA), Hyderabad, India 10. Liquid Propulsion Systems Center (LPSC) Bangalore & Mahendragiri, India 11. ISRO Inertial Systems Unit (IISU),Thiruvananthapuram, India International Groups participating in Chandrayaan Mission -1 are 12. Rutherford Appleton Laboratory, UK 13. Max Planck Institute for Aeronomy, Lindau,Germany 14. Swedish Institute of Space Physics, Kiruna, Sweden 15. Solar-Terrestrial Influences Laboratory, Bulgarian Academy of Sciences, Sofia, Bulgaria 16. Institute for Radiological Protection & Nuclear Safety, France 17. Nuclear Physics Institute, Czech Academy of Sciences, Czechoslovakia 18. Applied Physics Lab, Johns Hopkins University, MD, USA 19. Naval Air Warfare Centre, Chinalake, CA, USA 20. Brown University, USA 21. Jet Propulsion Laboratory, USA 22. Centre d'Etude Spatiale des Rayonnements, Toulouse, France 23. University of Helsinki, Finland

ISRO is also planning a second version of Chandrayaan named: Chandrayaan II. According to ISRO Chairman G. Madhavan Nair, "The Indian Space Research Organisation (ISRO) hopes to land a motorised rover on the moon in 2010 or 2011, as a part of its second Chandrayaan mission. The rover will be designed to move on wheels on the lunar surface, pick up samples of soil or rocks, do in situ chemical analysis & send the data to the mother-spacecraft Chandrayaan II, which will be orbiting above. Chandrayaan II will transmit the data to the ground. We are trying to conceive an experiment in which the system will land on the lunar surface, move around & pick up samples, do their chemical analysis & transmit the data back to the ground."

On 12-11-2007 representatives of the Russian Federal Space Agency & ISRO signed an agreement for the two agencies to work together on the Chandrayaan II project.

Chandrayaan II will consist of the spacecraft itself & a landing platform with the moon rover. The platform with the rover will detach from the orbiter after the spacecraft reaches its orbit above the moon, & land on lunar soil. Then the rover will roll out of the platform. Mylswamy Annadurai, Project Director, Chandrayaan I, said: "Chandrayaan II will carry a semi-hard or soft-landing system. A motorised rover will be released on the moon's surface from the lander. The location for the lander will be identified using Chandrayaan I data."

The rover will weigh between 30 kg & 100 kg, depending on whether it is to do a semi-hard landing or soft landing. The rover will have an operating life-span of a month. It will run predominantly on solar power. Launch Date - 2010/2011

According to Ben Bussey, senior staff scientist at The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, Chandrayaan's imagery will be used to decide the future Moon Base that NASA has recently announced. Bussey told SPACE.com, "India's Chandrayaan-1 lunar orbiter has a good shot at further identifying possible water ice-laden spots with a U.S.-provided low-power imaging radar, Bussey advised--one of two U.S. experiments on the Indian Moon probe. The idea is that we find regions of interest with Chandrayaan-1 radar. We would investigate those using all the capabilities of the radar on NASA's Lunar Reconnaissance Orbiter, Bussey added, a Moon probe to be launched late in 2008." The launch date for the LRO has since been delayed to February 2009.