India's solar mission will study the Sun's outermost layers — the corona and the chromosphere — and collect data about coronal mass ejection
After a seven year long wait, Aditya, India’s first dedicated scientific
mission to study the sun is likely to get a go-ahead from the Prime
Minister’s Office (PMO) this week. The ambitious solar mission will
study the sun’s outer most layers, the corona and the chromosphere,
collect data about coronal mass ejection and more, which will also yield
information for space weather prediction.
The project costs approximately Rs 400 crores and is a joint venture
between ISRO and physicists from Indian Institute of Astrophysics,
Bengaluru; Inter University Centre for Astronomy and Astrophysics, Pune;
Tata Institute of Fundamental Research, Mumbai, and other institutes.
In a three-body problem such as this – with the earth and sun engaged in
an elliptical orbit and a relatively very light, call it massless in
comparison, satellite being placed in between – there are five so-called
lagrangian points in space where the light, third body — in our case,
the satellite — may be placed so that it can maintain its position with
respect to the two others. One of these is the L1 point, which is about
1.5 million km from the earth.
A halo orbit would be a circular orbit around the L1 point. The
satellite will have to use its own power (spend energy) to remain in
position within in this orbit without losing its way. Such orbits have
not been attempted too often.
Studying the corona
Among the suite of instruments in the payload would be a solar
coronagraph. “A combination of imaging and spectroscopy in
multi-wavelength will enhance our understanding of the solar atmosphere.
It will provide high time cadence sharp images of the solar
chromosphere and the corona in the emission lines. These images will be
used to study the highly dynamic nature of the solar corona including
the small-scale coronal loops and large-scale Coronal Mass Ejections,”
said Dipankar Banerjee, physicist from IIA, who is part of this project.
The corona is the outermost layer of the Sun and the chromosphere is
the second inner layer. Data such as this can help us understand the
corona and solar wind, which is a spewing of charged particles into
space, at speeds as high as 900 km/s and at about 1 million degrees
Celsius temperature, affecting the environment there.
Just like on earth, environment in space changes due to happenings in
the sun, such as solar storms (flares). This is known as space weather.
Dibyendu Nandi, Head of Center of Excellence in Space Sciences, IISER,
Kolkata, describes it so: “Solar storms and space weather affect
satellite operations. They may interfere with electronic circuitry of
satellites and also, through enhanced drag (friction effects), impact
satellite mission lifetimes. They also impact the positional accuracy of
satellites and thus impact GPS navigational networks. Space weather
also impacts telecommunications, satellite TV broadcasts which are
dependent on satellite-based transmission.”
Dr Nandi works in building models that can predict space weather.
Hopeful about Aditya’s contribution to this, he remarks “The data from
Aditya mission will be immensely helpful in discriminating between
different models for the origin of solar storms and also for
constraining how the storms evolve and what path they take through the
interplanetary space from the Sun to the Earth. The forecasting models
we are building will therefore be complemented by the Aditya
observations.”
At the moment, there are models and calculations made by NASA which
Indian scientists use to maintain their satellites. Now, there is a
possibility of Indians developing their own space weather prediction
models.
