As interplanetary navigation is positioning and continuous tracking of interplanetary space probes and their direction or position control referred. All four tasks are the prerequisite for the precise control of flight paths in the solar system and also in its outer space.
The speed and location are determined by special observation stations on earth, sometimes also on earth satellites. The orbit of the probes can be determined in two coordinate systems, depending on the objective of the mission:
- geocentric (with respect to the earth, especially during moon flights ), or
- barycentric (with respect to the center of gravity of the solar system ), what else
- the topocentric system of the probe comes. The latter is important for various methods of on-board autonomous navigation of the spacecraft.
In contrast to the two - or three-dimensional navigation in nautical and aviation in which space the time as the fourth dimension crucial because the are to be achieved in rapid motion. In addition, the missile's drive is only active for a short time, which means that even the smallest errors lead to large deviations from the path.
Location methods from the earth
- with radio waves:
- Direction measurement with large radio telescopes , e.g. B. the Deep Space Network . A very high level of accuracy can be achieved with the Delta-DOR method .
- Interferometry analogous to the VLBI method
- Distance measurement based on the radar principle
- Speed by means of Doppler effect and
- Distance differences from its integration (analogous to hyperbola navigation ).
On-board autonomous methods
- Spatial orientation through sun and star sensors , v. a. for position control
- Infrared homing (control of celestial bodies with an infrared sensor)
- Gyro stabilization and inertial navigation (acceleration measurement )
- Direction measurement to planets, especially when flying past (e.g. at Cassini-Huygens )
- Satellite-to-Satellite Tracking (only near the earth)
- Analysis of gravity gradients and magnetic fields
- Comparison of the arrival times of pulsar signals
- Transition lanes , flyby (space travel)
- astronomical navigation
- Stabilization (space travel) , steering nozzle
- Richard Gliese : Space Research Volume I (p.181, 191ff), Bibl.Inst. Heidelberg 1966
- Udo Renner et al .: Satellite technology - an introduction . Springer-Verlag Berlin-Heidelberg 1988
- Ernst Messerschmid , Stefanos Fasoulas: Space systems. An introduction with exercises and solutions . Springer, Berlin 2005, ISBN 3-540-21037-7