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Helios
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Helios 1 and Helios 2 were a pair of deep space probes
developed by the Federal Republic of Germany (FRG) in a cooperative
program with NASA. Experiments were provided by scientists from both FRG
and the U.S. NASA supplied the Titan/Centaur launch vehicle. Each
spacecraft was equipped with two booms and a 32 m electric dipole.
The payload consisted of a fluxgate magnetometer; electric and magnetic
wave experiments, which covered various bands in the frequency range
6 Hz to 3 MHz; charged-particle experiments, which covered
various energy ranges starting with solar wind thermal energies and
extending to 1 GeV; a zodiacal-light experiment; and a
micrometeoroid experiment. The purpose of the mission was to make
pioneering measurements of the interplanetary medium from the vicinity
of the earth's orbit to 0.3 AU. The spin axis was normal to the
ecliptic, and the nominal spin rate was 1 rps. Instrument
descriptions written by the experimenters were published in Raumfahrtforschung 19/5 (1975).
The largest data base of
Helios data
available on the World Wide Web is provided by the National Space Science Data
Center (
NSSDC). Hourly Helios 1
& 2 plasma and magnetic field data are contained within the
COHOWeb interface. The value
of COHOWeb, besides its data subsetting and graphical display functionalities,
is that each of many deep space spacecraft (Ulysses, Voyagers 1&2,
Pioneers 10&11, etc.) have common data records (IMF vectors in a common
coordinate system, s/c position vectors in a common coordinate system, etc.).
This is an excellent starting point for multipoint studies of interplanetary
phenomena (spatial structures and evolutions of interplanetary shocks, CME's,
etc.).
Plots of the Helios mission
heliocentric trajectories.
Principal investigator: H. Rosenbauer
The plasma experiment aboard the Helios solar probes consists of four independent instruments designed to investigate the solar wind plasma. By measuring the velocity distribution functions of the different kinds of particles, all important hydrodynamic parameters of the solar wind plasma can be derived. Three instruments (I1a, I1b, and I3) analyze the positive components (protons and heavier ions with energy-per-charge values from 0.155 to 15.32 kV) of the solar wind. Two of them allow for an angular resolution in both directions of incidence. One instrument (I2) measures electrons in the energy range from 0.5 the 1660 eV with one-dimensional angular resolution.
Principal investigator: F. B. Neubauer
The flux-gate magnetometer experiments use triaxial, orthogonal flux-gate sensors of the Forster type mounted on a boom of about 2 m from the spacecraft. The bandwidth is 4 Hz. Two measuring ranges are used with automatic switching. The sensitivity range extends from -100 nT to +100 nT.
The complete merged data set for the plasma experiment E1 and magnetometer experiment E2 for both Helios 1 and Helios 2 is available for local use at MPS on 19 MODs. The E2 data is averaged to match the time resolution of the E1 data. (Highest time resolution: 40.5 s/spectrum.)
Selected parameters of the complete data set (19 MODs) have been
compressed to fit on one CD. Documentation
Principal investigator: D. A. Gurnett
The University of Iowa
plasma
wave experiment (E5a) utilized the 32 m tip-to-tip dipole antenna to
detect the electric component of plasma waves.
Principal investigator: H. Kunow
The cosmic ray
particle
experiment E6 (University of Kiel) consists of a detector telescope
containing five semiconductor detectors of increasing thickness, a sapphire
Cerenkov deteector surrounded by an anticoincidence scintillation detector,
and an on-board handling system. The instrument is capable of measuring
protons and heavier nuclei from 1.7 to more than 400 MeV/n and MeV
electrons.
Principal investigator: E. Keppler
The spectrometer utilizes an inhomogenous magnetic field for separation of charged particles. Protons (and heavier particles) traverse the magnetic field almost unaffected and are detected in a telescope arrangement consisting of two semiconductor detectors. Electrons are focused and detected by four semiconductor detectors. Positrons (if present) are deflected in the opposite direction and detected in another detector.
© 2006, Max-Planck-Institut für Sonnensystemforschung, Lindau |
Kevin Ivory 22-02-1999 |