Chandrayaan 1

Launch data: Designation  33405 / 08052A Launch date  22 Oct 2008 - 00:52 UT (6:22 am. local time) Launch site  Sriharikota, SLP Launch vehicle  PSLV Mission  Lunar probe Perigee / Apogee   km Eccentricity   Inclination   deg Period   min

Spacecraft data: Prime contractor   Platform   Operator  ISRO Mass at launch  1380 kg Mass at lunar orbit  675 kg Basic shape  cube Dimension (m)  appr. 1.5m side Solar array  one Stabilization  3-axis stabilized spacecraft using two star sensors, gyros and four reaction wheels. DC power  750 W Design lifetime

Photo of the Chandrayaan-1 spacecraft during integration (image credit: ISRO)

Artist's view of the S/C mission profile toward the moon (image credit: ISRO)

LEOP (Launch and Early Orbit Phase) orbit determination of Chandrayaan-1 (image credit: ISRO)

Description:

• Chandrayaan-1 is an Indian Space Research Organization (ISRO) mission designed to orbit the Moon over a two year period with the objectives of upgrading and testing India's technological capabilities in space and returning scientific information on the lunar surface. The spacecraft bus is roughly a 1.5 meter cube with a dry weight of 523 kg (Launch mass of the system, including its Lunar Apogee Motor, LAM, is 1380 kg). It is based on the Kalpansat meteorological satellite. Power is provided by a solar array which generates 750 W and charges lithium ion batteries. A bipropellant propulsion system is used to transfer Chandrayaan-1 into lunar orbit and maintain attitude. The spacecraft is 3-axis stabilized using attitude control thrusters and reaction wheels. Knowledge is provided by star sensors, accelerometers, and an inertial reference unit. Telecommand communications will be in S-band and science data transmission in X-band.
• The scientific payload has a mass of 55 kg and contains three Indian instruments. The Terrain Mapping Camera (TMC) has 5 meter resolution and a 40 km swath in the panchromatic band and 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 and a spatial resolution of 80 m. The Lunar Laser Ranging Instrument (LLRI) will determine the surface topography. A fourth instrument, an X-ray flourescence spectrometer, will have three components: an Imaging X-ray Spectrometer (CIXS) covering 1 - 10 keV with a ground resolution of 10 km, a High Energy X-ray/gamma ray spectromenter (HEX) for 10 - 200 keV measurements with ground resolution of about 20 km, and a Solar X-ray Monitor (SXM) to detect solar flux in the 2 - 10 keV range. CIXS will be used to map the abundance of Si, Al, Mg, Ca, Fe, and Ti at the surface, the HEX will measure U, Th, 210Pb, 222Rn degassing, and other radioactive elements, and the SXM will monitor the solar flux to normalize the results of CIXS and HEX. The Sub-keV Atom Reflecting Analyzer (SARA) will map composition using low energy neutral atoms sputtered from the surface. The Moon Mineralogy Mapper (M3) is an imaging spectrometer designed to map the surface mineral composition. A near-infrared spectrometer (SIR-2) will also map the mineral composition using an infrared grating spectrometer. The Miniature Synthetic Aperture Radar (Mini-SAR) will perform radar scattering and imaging investigations at the poles in a search for water ice. A Bulgarian instrument, the Radiation Dose Monitor (RADOM-7), will also fly on the mission to characterize the local radiation environment.
• Chandrayaan-1 will also carry a 35 kg Moon Impact Probe (MIP) designed to be released from the spacecraft and hit the lunar surface. The MIP carried a video camera, a radar altimeter, and a mass spectrometer. The side panels of the box-like probe were painted with the Indian flag.
• 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 750W 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 and 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) Onboard to record data from various payloads.
  • SSR-1 will store science payload data and has capability of storing 32Gb data.
  • SSR-2 will store science payload data along with spacecraft attitude information (gyro and star sensor), satellite house keeping and other auxiliary data. The storing capacity of SSR-2 is 8Gb.
  • M3 (Moon Mineralogy Mapper) payload has an independent SSR with 10Gb capacity.

Mission details:

• India's first lunar probe, Chandrayaan-1, was launched by PSLV flight C11 from Sriharikota on Oct 22, 2008. Launch was at 00:52 UTC into a 225 x 22817 km x 17.9 deg initial orbit; the craft will use its own engines to inject itself on a translunar trajectory. An initial burn has raised the orbit to 301 x 37830 km.
• On Oct 29, 2008 Chandraayan-1's orbit was raised to 465 x 267000 km, on its way to lunar orbit. On Nov 3, the apogee was increased further to 380000 km.
• Chandrayaan-1 entered lunar orbit on Nov 8, 2008. ISRO reported the initial orbit as 504 x 7502 km x 90.0 deg. By Nov 12 the orbit had been lowered to 100 x 100 km x 90.0 deg. On Nov 14 at 14:36 UTC it ejected a 29 kg Moon Impact Probe (MIP). The MIP fired a small deorbit motor to lower its orbit to around -200 x 100 km, and hit the moon at 15:01 UTC, near Shackleton Crater at the south pole. All three instruments returned data before the crash. The orbiter will return data for at least two years.

External links:

• EOportal.org Satellite description
• Satellite tracking: Real time satellite tracking