Sounding rockets

• A sounding rocket, sometimes called a research rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight.
• Sounding rockets are advantageous for some research due to their low cost and their ability to conduct research in areas inaccessible to either balloons or satellites.
• They are also used for measurements in the upper atmosphere and microgravity research
• Thumba Equatorial Launching Centre of ISRO near Thiruvanantpuram uses Sounding rockets for research. Thumba is located near Earths magnetic equator.
  
• Rockets launched from this site are helpful to probe phenomena associated with the magnetic Equator – such as the electrojet, a stream of electric current flowing in a narrow band of three degrees on either side of the magnetic Equator at a height of 100 kms.
• The sounding rockets were used by ISRO to develop and test several sub-systems for advanced rockets and evaluate more powerful propellants.