Capital’s skies to sport spectacular hues today

On Friday, the skies above the city will sport a trail of white and blue light as a sounding rocket takes off from the Thumba Equatorial Rocket Launching Station (TERLS) here. Caused by a phenomenon known as chemi-luminescence, the display will be triggered by a sounding rocket experiment by the Vikram Sarabhai Space Centre (VSSC) to study the equatorial and lower ionosphere regions of the earth’s atmosphere. The study is aimed at enriching the available atmospheric data and refining the models used for tropical weather prediction

The programme utilises the RH-300 Mk2 rocket developed by the VSSC to measure neutral wind in the dynamo region (80-120 km) of the equatorial ionosphere and perform cross-validation using a technique known as independent Tri Methyl Aluminium (TMA) release.

Atmospheric studies with the TMA were conducted in the 1960s utilising sounding rockets of foreign make and the first launch on May 2, 1965 used a Centaure rocket.

The experiment is being attempted after a long gap with indigenously developed payload and rocket. TMA is a pyrophoric liquid that burns on contact with oxygen, the reaction producing a long-lasting chemi-luminescence that can be observed from the ground with the naked eye for a few minutes.

In twilight conditions, it produces both the white light associated with the chemi-luminescence and a strong blue light associated with an aluminium resonance emission line.

The 21st launch of the RH 300 sounding rocket is at 7.15 p.m.

The VSSC will capture photographic images of the trail from Thiruvananthapuram, Kollam, Kanyakumari and Tirunelveli.