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 rockets are used to carry instruments from above the surface of the
Earth, the altitude generally between
weather balloons and
satellites (the maximum altitude for
balloons is about and the minimum for
satellites is approximately ). Certain sounding rockets, such as the
Black Brant X and XII, have an
apogee between ; the maximum apogee of their class. Sounding rockets often use military surplus rocket motors.
NASA routinely flies the Terrier Mk 70 boosted
Improved Orion lifting payloads into the region between .