A dart is a free flying top of a sounding rocket

Sounding rocket

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, where to sound is to throw a weighted line from a ship into...

, and contains the payload. Its form is very aerodynamically

Aerodynamics

Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...

 designed. After the launch stage burned out the dart is detached and continues to rise only with its own inertia

Inertia

Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...

.

Some sounding rockets are available both with or without dart. The version without dart is able to transport more payload, but reaches lesser height.

Applications

• Mohr Rocket
  Mohr Rocket
  The Mohr Rocket was a sounding rocket developed by Ernst Mohr in Wuppertal, Germany.It was a single stage solid fuel rocket with:*a length of 1.7 metres,*a total mass of 150 kg ,*a lift-off thrust of 76.5 kN and a diameter of 0.3 m....
  
  
• MMR06
  MMR06
  The MMR06 is a Russian rocket for meteorological experiments, with a length of 3.48 metres and a total weight of 130 kg. The MMR06 rocket was built in two versions: One version had a conical top, the second one, named MMR06-M, had a detachable free flying top, also called dart. The maximum flight...
  
  
• Loki-Dart
• Meteor
  Meteor (rocket)
  Meteor is a designation of a series of Polish sounding rockets.The Meteor rockets were built between 1963 and 1974.The Meteor 1 and Meteor 2H were single-stage rockets. The Meteor 2K was a two-stage rocket. The Meteor 3 was a two-stage rocket, compound from two Meteor 1 rockets.Meteor rockets...