INDIAN
MARS ORBITER OUT OF EARTH'S INFLUENCE
The Indian Orbiter to Mars zoomed out of
the earth's sphere of influence on Wednesday while cruising in the sun orbit on
its 10-month long voyage to the red planet.
"The Mars Orbiter has traversed beyond the
earth's sphere of influence, which extends up to 925,000 km in the
interplanetary space at 1.14 a.m.," the Indian space agency said .
Exiting from the earth's sphere of influence means the spacecraft is out of its
gravitational pull and free to cruise in the 680-million km solar orbit to
reach Mars in mid-September 2014.
"Though sun's gravity dominates the solar system owing to its massive
size, only very near to planets, the planetary gravity becomes stronger than
that of sun and is referred as the sphere of influence," the state-run
Indian Space Research Organisation (ISRO) said.
Orbits of moon and artificial satellites around fall inside the earth's sphere
of influence.
A day after escaping from earth early Sunday, the spacecraft crossed early
Monday the moon's orbit, which is 385,000km away and became the farthest object
of India in the interplanetary space.
Scientists at the Indian telemetry, tracking and command network (Istrac) here
and the Indian Deep Space Network at Bylalu, about 40km from Bangalore, are
monitoring the spacecraft's movement in the sun-synchronous orbit and checking
its subsystems.
The deep space network will conduct the first of the four mid-course corrections
Dec 11 to ensure the Orbiter stays on course in the sun orbit.
After 290 days, the spacecraft will enter in mid-Sept the Mars sphere of
influence, which is around 573,473 km from its surface, in a hyperbolic
trajectory.
When the spacecraft is closest to Mars, it will be captured into the Martian
orbit through a crucial manoeuvre, which involves slowing its velocity (speed).
Transition from the earth's final orbit to solar orbit was programmed in line
with sun's gravity and laws of the universe to ensure Orbiter reaches precisely
on time to sling into the Martian orbit in mid-Sept.
The 1,337 kg Orbiter was launched Nov 5 from Sriharikota spaceport off the Bay
of Bengal, about 80km north east of Chennai, onboard a 350-tonne rocket with
five scientific instruments -- Mars Colour Camera, Methane Sensor, Thermal
Infrared Imaging Spectrometer, Lyman Alpha Photometer, and Mars exospheric
Netural Composition Analyser.
India became the first Asian country and fourth nation in the world to leap
into the interplanetary space with its Rs.450-crore exploratory mission to
Mars, about 400 million km from earth.
So far, only Russia, US and the European Space Agency (ESA) have undertaken
such missions.
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