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. The origin of the term comes from nautical vocabulary, it refers to to sound, which means to throw a weighted line off of a ship to gauge the water's depth. It is intended here as taking a measurement.
The rockets are commonly used to take readings or carry instruments from 50 to 1,500 kilometers (30–932 mi) above the surface of the Earth, the altitude generally between weather balloons and satellites; the region above the maximum altitude for balloons is about 40 km (25 miles) and the minimum for satellites is approximately 120 kilometers (75 mi). Certain sounding rockets, such as the Black Brant X and XII, have an apogee between 1,000 and 1,500 kilometers (621–932 mi); the maximum apogee of their class. Sounding rockets often use military surplus rocket motors. NASA routinely flies the Terrier Mk 70 boosted Improved Orion lofting 270–450 kilogram (600–1000 lb) payloads into the exoatmospheric region between 100 and 200 kilometers (62–124 mi).
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
allowing the payload to appear to hover near its apogee
. The average flight time is less than 40 minutes, usually between five and 20 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
Sounding rockets are advantageous for some research due to their low cost, short lead time (sometimes less than six months) and their ability (as mentioned above) to conduct research in areas inaccessible to either balloons or satellites. They are also used as test beds for equipment that will be used in more expensive and risky orbital spaceflight
missions. The smaller size of a sounding rocket also makes launching from temporary sites possible allowing for field studies at remote locations, even in the middle of the ocean, if fired from a ship.
- The British Skylark (rocket) was designed in 1955 and had over four hundred launches before ceasing use in 2005.
- Rocket Lab Develops and launches the highly adaptable Atea series of sounding rockets to carry payloads between 10 and 70 kg to altitudes in excess of 250 km.
- The Australian Space Research Institute (ASRI) operates a Small Sounding Rocket Program (SSRP) for launching payloads (mostly educational) to altitudes of about 7 km.
- Iranian Space Agency operated its first sounding rocket in February 2007.
- UP Aerospace operates the UP Aerospace SpaceLoftXL sounding rockets that can reach altitudes of 225 km.
- The German TEXUS and MINITEXUS Programmes.
- The Swedish Space Corporation's MASER Programme, for payloads up to 395kg and/or 320km.
- The EADS-ST and Swedish Space Corporation MAXUS Programme.
- The NASA Sounding Rocket Program
- The JAXA operate the sounding rockets S-310/S-520/SS-520
- Beyond-Earth Enterprises
- REXUS Program of the Swedish Space Corporation