PSLV-C11 Successfully Launches Chandrayaan-1          October 22, 2008  
	

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.