A sounding rocket is an instrument carrying suborbital rocket designed to take measurements and perform scientific experiments during its flight.

The rockets are commonly used to take readings or carry instruments from 50 to 200 km above the surface, the region above the maximum altitude for balloons and below the minimum for satellites. The term 'sounding' is taken from the maritime expression. Certain sounding rockets, such as the Black Brant X and XII, have an apogee between 1,000 and 1,500 km, well above Low Earth Orbit.

A common sounding rocket consists of a solid-fuel rocket motor and a payload. The freefall part of the flight is an elliptic trajectory with vertical major axis and the average flight time is less than forty minutes. The rocket consumes its fuel on the first stage of the rising part of the flight, then separates and falls away, leaving the payload to complete the arc and return to the ground with a parachute.

External links

• NASA Sounding Rockets Program Office (http://www.wff.nasa.gov/~code810/)
• NASA Sounding Rocket Operations Contract (http://www.nsroc.com/front/mainmenu/mmframe.html)
• NASA Sounding Rockets, 1958-1968: A Historical Summary (NASA SP-4401, 1971) (http://history.nasa.gov/SP-4401/sp4401.htm)