In its fourteenth
flight conducted from Satish Dhawan
Space Centre (SDSC) SHAR, Sriharikota this morning (October
22, 2008), the Indian Space Research Organisation’s (ISRO’s)
Polar Satellite Launch Vehicle, PSLV-C11, successfully launched the 1380 kg Chandrayaan-1
spacecraft into a transfer orbit with a perigee (nearest point to
Earth) of 255 km and an apogee (farthest point to Earth) of 22,860 km, inclined
at an angle of 17.9 deg to the equator.
After a 52 hour count
down, PSLV-C11 lifted off from the Second Launch Pad at SDSC SHAR at 06:22 Hrs Indian Standard Time (IST) with the ignition of the core
first stage. The important flight events included the separation of the first
stage, ignition of the second stage, separation of the payload fairing at about
116 km altitude after the vehicle had cleared the dense atmosphere, second
stage separation, third stage ignition, third stage separation, fourth stage
ignition and fourth stage cut-off.
PSLV-C11 is the uprated version of ISRO’s Polar
Satellite Launch Vehicle in its standard configuration. Weighing 320 tonnes at
lift-off, the vehicle uses larger strap-on motors (PSOM-XL) to achieve higher
payload capability. PSOM-XL uses 12 tonnes of solid propellants instead of 9
tonnes used in the earlier configuration of PSLV. PSLV is a four stage launch
vehicle employing both solid and liquid propulsion stages. PSLV is the trusted
workhorse launch Vehicle of ISRO. During 1993-2008 period, PSLV had fourteen
launches of which thirteen (including today’s launch) are consecutively
successful. PSLV has repeatedly proved its reliability and versatility by
launching 30 spacecraft (14 Indian and 16 for international customers) into a
variety of orbits so far.
Vikram Sarabhai
Space Centre (VSSC), Thiruvananthapuram, designed and
developed PSLV. ISRO Inertial Systems Unit (IISU) at Thiruvananthapuram
developed the inertial systems. The Liquid Propulsion Systems Centre (LPSC),
also at Thiruvananthapuram, developed the liquid
propulsion stages for the second and fourth stages of PSLV as well as reaction
control systems. SDSC SHAR processed the solid propellant motors and carried
out launch operations. ISRO Telemetry, Tracking and Command Network (ISTRAC)
provided telemetry, tracking and command support.
Chandrayaan-1 is India’s first spacecraft mission beyond Earth’s orbit. It aims to
further expand our knowledge about Earth’s only natural satellite – the moon.
With well-defined objectives, Chandrayaan-1 mission intends to put an unmanned
spacecraft into an orbit around the moon and to perform remote sensing of our
nearest celestial neighbour for about two years using eleven scientific
instruments built in India and five other countries.
The primary
objectives of Chandrayaan-1 are:
- To
place an unmanned spacecraft in an orbit around the moon
- To
conduct mineralogical and chemical mapping of the lunar surface
- To
upgrade the technological base in the country
Chandrayaan-1 aims to
achieve these well-defined objectives through high-resolution remote sensing of
moon in the visible, near infrared, microwave and X-ray regions of the
electromagnetic spectrum. With this, preparation of a 3-dimensional atlas of
the lunar surface and chemical and mineralogical mapping of entire lunar
surface is envisaged.
PSLV placed the
Chandrayaan-1 spacecraft into a highly elliptical Transfer Orbit (TO) around
the earth. Later, through a series of highly complex manoeuvres, the desired
trajectories will be achieved. After circling the Earth in its Transfer Orbit,
Chandrayaan-1 spacecraft will be taken into more elliptical ‘Extended Transfer
Orbits’ by repeatedly firing its Liquid Apogee Motor (LAM) in a pr-determined
sequence. Subsequently, the LAM is again fired to make the spacecraft to travel
to the vicinity of the moon.
When it reaches the
vicinity of the Moon and passes at a few hundred kilometers
from it, its LAM is fired again so that the spacecraft slows down sufficiently
to enable the gravity of the moon to capture it into an elliptical orbit.
Following this, the
height of the spacecraft’s orbit around the moon is reduced in steps. After a
careful and detailed observation of the orbit perturbations there, the orbital
height of Chandrayaan-1 will be finally lowered to its intended 100 km height
from the lunar surface. Moon Impact Probe will be ejected from Chandrayaan-1
spacecraft at the earliest opportunity to hit the lunar surface in a chosen
area.
Later, cameras and
other scientific instruments are turned ON and thoroughly tested. This leads to
the operational phase of the mission. This phase lasts for about two years
during which Chandrayaan-1 spacecraft explores the lunar surface with its array
of instruments that includes cameras, spectrometers and SAR.
The Payloads: There are 11 payloads (scientific instruments) through which
Chandrayaan-1 intends to achieve its scientific objectives.
They include five
instruments designed and developed in India, three instruments from European Space Agency (one of which is
developed jointly with India and the other with Indian contribution), one from Bulgaria and two from the United States.
The Indian payloads
of Chandrayaan-1 are:
Terrain Mapping
Camera (TMC), a CCD camera that maps the topography
of the moon, which helps in better understanding of the lunar evolution
process.
Hyperspectral Imager (HySI), another CCD camera, is designed
for mapping of the minerals on the lunar surface as well as for understanding
the mineralogical composition of Moon’s interior.
Lunar Laser Ranging
Instrument (LLRI) provides necessary data for accurately
determining the height of lunar surface features.
High Energy X-ray
Spectrometer (HEX) is designed to help explore the
possibility of identifying Polar Regions covered by thick water-ice deposits as well as in identifying
regions of high Uranium and Thorium concentrations.
Moon Impact Probe
(MIP) demonstrates the technologies required for landing a probe
at the desired location on the moon. It is also intended to qualify some of the
technologies related to future soft landing missions.
The six international
payloads of Chandrayaan-1 are:
Chandrayaan-1 Imaging
X ray Spectrometer (C1XS), an ESA payload and jointly
developed by Rutherford Appleton Laboratory of England and ISRO Satellite
Centre, Bangalore, intends is to carry out high quality mapping of the moon
using X-ray fluorescence technique for finding the presnce
of Magnesium, Aluminium, Silicon, Iron and Titanium distributed over the
surface of the Moon.
Smart Near Infrared
Spectrometer (SIR-2), another ESA payload, developed by Max
Plank Institute of Germany, aims to study the lunar surface to explore the
mineral resources and the formation of its surface features.
Sub kiloelectronvolt Atom Reflecting Analyser (SAR), the third payload from ESA, is built by Swedish Institute of
Space Physics and Space Physics Laboratory of Vikram Sarabhai Space Centre, Tiruvananthapuram.
The aim of this instrument is to study the surface composition of the moon and
the magnetic anomalies associated with the surface of the moon.
Radiation Dose
Monitor (RADOM), a payload developed by Bulgarian Academy of Sciences, aims to characterise the radiation environment in a
region of space surrounding the moon.
Mini Synthetic
Aperture Radar (MiniSAR) is one of the two scientific instruments from the USA and is from Johns Hopkins University’s Applied Physics Laboratory and Naval Air Warfare Centre, USA through NASA. MiniSAR is mainly
intended for detecting water ice in the permanently shadowed regions of the
lunar poles up to a depth of a few meters.
Moon Mineralogy Mapper (M3) is an imaging spectrometer
from Brown University and Jet Propulsion Laboratory of the US through NASA, is intended to assess and
map lunar mineral resources at high spatial and spectral resolution.
The Spacecraft: Chandrayaan-1 spacecraft weighed about 1380 kg at the time of its
launch and is a 1.5 m cuboid with a solar panel
projecting from one of its sides. The spacecraft is powered by a single solar
panel generating electrical power of 700 W. A Lithium ion battery supplies
power when the solar panel is not illuminated by the sun. To make Chandrayaan-1
spacecraft to travel towards the Moon, its Liquid Apogee Motor (LAM) is used.
Liquid propellants needed for LAM as well as thrusters are stored onboard the
spacecraft. Chandrayaan-1 spacecraft’s Dual Gimballed Antenna transmits the
scientific data gathered by its eleven scientific instruments to Earth.
Chandrayaan-1
spacecraft was built at ISRO Satellite Centre, Bangalore with
contributions from Vikram Sarabhai
Space Centre (VSSC), Liquid Propulsion Systems Centre (LPSC) and ISRO Inertial
Systems Unit (IISU) at Tiruvananthapuram, Space
Applications Centre (SAC) and Physical Research Laboratory (PRL), Ahmedabad and Laboratory for Electro-optic Systems (LEOS), Bangalore.
The Ground Segment: The Ground facilities of Chandrayaan-1 perform the important task
of receiving the health information as well as the scientific data from the
spacecraft. It also transmits the radio commands to be sent to the spacecraft
during all the phases of its mission. Besides, it processes and stores the
scientific data sent by Chandrayaan-1 spacecraft.
ISRO Telemetry,
Tracking and Command Network (ISTRAC) had a lead role in establishing the
Ground Segment of Chandrayaan-1 with contributions from ISAC and SAC. The
Ground Segment of Chandrayaan-1 consists of:
- Indian
Deep Space Network (IDSN)
- Spacecraft
Control Centre (SCC)
- Indian
Space Science Data Centre (ISSDC)
The Indian Deep Space
Network receives the data sent by the Chandrayaan-1 spacecraft.
Besides, it sends commands to the spacecraft at a power level of upto 20 kilowatts. IDSN consists of two large parabolic
antennas – one with 18 m diameter and the other 32 m diameter – at Byalalu, situated at a distance of about 35 km from Bangalore. Of these the
32 m antenna with its ‘seven mirror beam waveguide system’, was indigenously
designed, developed, built, installed, tested and qualified. The 18 m antenna
can support Chandrayaan-1 mission, but the 32m antenna can support spacecraft
missions well beyond Moon.
The Spacecraft
Control Centre, located near the ISTRAC campus at Peenya, North of Bangalore, is the focal point of all the
operational activities of Chandrayaan-1 during all the phases of the mission.
The Indian Space
Science Data Centre forms the third element of
Chandrayaan-1 ground segment. Also located at Byalalu,
ISSDC receives data from IDSN as well as other external stations that support
Chandrayaan-1, stores, processes, archives, retrieves and distributes
scientific data sent by Chandrayaan-1 payloads to the user agencies.
RJ/PRA/SKK
(Release ID :44429)