Prof. Dr. Karl-Heinz Glaßmeier
Dr. Günter Musmann
Dr. Falko Kuhnke
Dr. Ingo Richter
Dipl. Phys. Carsten Othmer

Project Summary

DEEPSPACE 1 (DS1) is the first   satellite mission  of  the National Aeronautics and Space Administrations (NASA) New Millennium Programme. It is aimed to test and validate the   12 new  kinds of  space technology for the space science of the next millennium. The main features are:

Primary mission trajectoryDS1 was launched successfully on October 24th, 1998 at  Kennedy Space Flight Center, Cap Caneveral, Florida  aboard a  Delta 7326-9.5 Med-Lite  rocket (for the first time). DS1 has a mass of  486 kg and contains 81 kg  Xenon gas for the ion propulsion system. The primary mission objective was a rendezvous with the  asteroid 1992 KD (now called Braille)  on  July 29th, 1999. The closest approach took place in a distance of 1.3 AU from the sun.  This encounter was so close (about 25 km) to the asteroid  as never  ever reached  by a satellite before to any celestial body. At this encounter the complete navigation as well as the flight and attitude conrtrol was managed by the new developped  autonomous navigation system AutoNav. This system is based on  a camera (MICAS), which scans  and records the firmament, and a  reference star data base for a realtime onboard  evaluation of the  precise position and the orientation of the spaceraft. Up to two days prior to the rendezvous the
ion propulsion system was used for spacecraft control;  in the last 48 hours  before the closest approach to the asteroid, however, 8 conventional thrusters  (Hydrazin, 28 kg) were brought into action, to provide  the possibility of  quick direction corrections needed in certain cases.
During the complete cruise of DS1 our fluxgate magnetometer trnsmits precious magnetic field data. Within the scope of the DS1 Mission investigations take place, in how far it is possible to get scientic significant magnetic field data of the covered flight area, using an ion propulsion system equippped spacecraft. Special problems arise due to the ion current, which produces ist own magnetic field, and on the othe hand the movable ion beam focusing magnets , that show a temperature dependent magnetic disturbance field.
Magnetic field modells are created that contain all neccessary satellite parameteres to eliminate the disturbance components from the measured magentic field data.

The Ion Propulsion System

DS1 gets its thrust from a  solar-electrical ion  propulsion. The power for the propulsion is supplied by the two solar arrays. The inert gas Xenon, which is about 4.5 times heavier than  air, is used to produce the  repulsion.
The gas in ionized in the enigine through ionization  by collision . The ions are accellerated  to a maximum ejection  velocity of 110000 km/h  by running through a potential difference of up to 1280 V.  This process generates an effective thrust of about 90 mN. This corresponds to a pressure, that a piece of paper, lying on the hand, will apply to the hand .  This thrust is in deed very low and would never be sufficient to launch a spacecraft from the earth, but as it can be kept over months (there is enough Xe gas for a 6000 h operation endurance) and thus provides a continous accelleration
amazing velocities can be reached. After the consumption of all the fuel DS1 will have perveived a relative velocity increase of about 15000 km/h. It is quite remarkable and should be mentioned that the ion propulsion generates about ten times more thrust than a conventional fluid or solid fuel rocket using the same amount of fuel. The ion engine has a diameter of  40 cm, is 40 cm long and has a weight of about 8 kg.

For the characterization of the plasma dynamics in the vicinity of the ion enigine a  plasma simulation  is developed at the Institute for Geophysics and Meteorology in cooperation with the  Institute  for Theoretical Physics and the Computation Center of the Technical University Braunschweig.

Ionentriebwerk schematisch


The Magnetometer

A high sensitive subminiatur vector  fluxgate magnetometer was developed at the Institute for Geophysics and Meteorology. It has been designed for the extremely high requirements in space:

Magnetometer-Elektronik 1Magnetometer-Elektronik digital

After the successful test phase the magnetometers were calibrated in  Magnetsrode, the magnetic coil facility of our institute. The extensive test procedure of  such a calibration contains:

DS1 is equipped with two of these magnetometers. They are located outside the spacecraft on  an external boom.

More DEEPSPACE 1-Pages:

 IGM - Numerical Simulation of the Ion Engine
  NASA /JPL -DS1 Homepage
  NASA /JPL -Missions Status
  Institute for Space Research, GRAZ
Last Change: 21.01.2000.