Helios mission support
Activities of the network operations organization are reported in support of the Helios Project during December 1976 and January 1977.
Goodwin, P. S.↗
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Preliminary analysis of coronal electron content measurements from spacecraft Helios A around first solar occultation
Steady-state and dynamical features of the electron density distribution in the solar corona emerge from a preliminary analysis of Helios A electron content measurements. There are strong indications that correlations can be established with earth-bound K-coronagraph measurements.
Edenhofer, P.↗
Magnetic fields and flows between 1 AU and 0.3 AU during the primary mission of HELIOS 1
The recurrent flow and field patterns observed by HELIOS 1, and the relation between these patterns and coronal holes are discussed. Four types of recurrent patterns were observed: a large recurrent stream, a recurrent slow (quiet) flow, a rapidly evolving flow, and a recurrent compound stream. There recurrent streams were not stationary, for although the sources recurred at approximately the same longitudes on successive rotations, the shapes and latitudinal patterns changed from one rotation to the next. A type of magnetic field and plasma structure characterized by a low ion temperature and a high magnetic field intensity is described as well as the structures of stream boundaries between the sun at approximately 0.3 AU.
Burlaga, L. F.↗
Helios mission support
Activities of the Network Operations organization in support of the Helios Project from 15 August 1977 through 15 October 1977 are reported. Included in this article is information on the Mark 3 Data Subsystem update at the conjoint Deep Space Station 42/43 complex (Canberra, Australia), an update on Radio Science Activities, and other mission-oriented activities.
Goodwin, P. S.↗
Helios mission support
Activities of the Deep Space Network Operations organization in support of the Helios Project from 15 October 1977 through 15 December 1977 are described. Topics covered include: (1) Mark 3 data subsystem testing at the conjoint Deep Space Stations (DSS) 42/43 (Canberra, Australia); (2) MDS implementation at DSS 61/63 (Madrid, Spain); (3) Radio Science update, and (4) other mission-related activities.
Goodwin, P. S.↗
Helios mission support
Activities of the DSN network operations organization in support of the Helios Project from February 15, 1978 through April 15, 1978 are reported. Mark 3 data subsystems (MDS) testing at the Deep Space Station 2 (Goldstone, Calif.) is included.
Goodwin, P. S.↗
Radial dependence of solar wind properties deduced from Helios 1/2 and Pioneer 10/11 radio scattering observations
Radio scattering measurements at 2.3 GHz, conducted over the heliocentric distance range of 1.7 to 180 solar radii, provide data for a study of the radial dependence of the solar wind characteristics. The data are obtained from the Helios 1 and 2 and the Pioneer 10 and 11 spacecraft. Spectral broadening measurements, together with angular broadening data for the spacecraft signal, indicate a value of 24 km/sec for the solar wind velocity at 1.7 solar radii. A velocity profile of the solar wind in the acceleration range is developed. In addition, phase scintillation measurements obtained suggest that the solar wind is slightly converging in the equatorial region between approximately 20 and 180 solar radii.
Woo, R.↗
Characterization of solar cells for space applications. Volume 4: Electrical characteristics of Spectrolab BSF 200-micron Helios cells as a function of intensity and temperature
Electrical characteristics of Spectrolab BSF 200 micron Helios N/P silicon solar cells are presented in graphical and tabular format as a function of solar illumination intensity and temperature.
Downing, R. G.↗
Helios mission support
Activities of the DSN Network Operations Organization in support of the Helios Project from 15 August 1978 through 15 October 1978 are reported.
Goodwin, P. S.↗
Helios missile support
This article reports on activities of the DSN Network Operations Organization in support of the Helios Project from 15 October through 15 December 1978.
Jensen, W. N.↗
Helios-Voyager cooperation for the investigation of the interplanetary space
The planning of a joint mission involving the two Helios spacecraft and the two Voyager spacecraft is reported. During late fall 1977 the position of the four spacecraft facilitated correlation measurements as part of an investigation of interplanetary space in the vicinity of the earth. The spacecraft and their orbits are described, and the benefits that could result from future joint missions are considered.
Porsche, H.↗
The large-scale structure of the interplanetary magnetic field between 1 and 0.3 AU during the primary mission of Helios 1
The macroscale and mesoscale structure of the interplanetary magnetic field during the primary mission of Helios 1 is discussed. The radial field component behaves essentially in agreement with Parker's theory. The transverse component shows a larger variability than the radial component; its radial variation is in good agreement with Parker's theory for high speeds, but some deviation is found for low speeds. The radial variation of the field variance is also studied. Its dependence upon the heliocentric distance r is expressed by the law 1/r cubed, which is necessary but not sufficient for Alfven waves. The available data do not allow a unique interpretation of the 1/r cubed dependence. No big differences are observed between low (less than or equal to 500 km/s) and high (greater than or equal to 600 km/s) solar wind velocity regimes.
Mariani, F.↗
Magnetic fields and flows between 1 and 0.3 AU during the primary mission of Helios 1
Magnetic phenomena and coronal holes observed by Helios 1 during nearly four rotations of the sun are discussed. It is estimated that the magnetic field intensity of open field lines in some of the coronal holes (which changed in shape and latitude from one rotation to the next) was of the order of 10-20 G during the studied period, December 1974 to March 1975. Magnetic field polarity, cold magnetic enhancements, and longitudinal widths of the stream are described. It is concluded that between the sun and 0.3 AU there was a diverging stream surrounded by a thin boundary layer in which there was large velocity shear. There is evidence for compression of the magnetic field in the western boundary layer.
Burlaga, L. F.↗
Problems of extremely long-duration missions in the inner solar system - Example Helios
The paper deals with the exploration of the region between the earth and the sun by means of the Helios I and II spacecraft, launched in December 1974 and January 1976, respectively. Initially intended for quiet-sun observations over a period of 18 months, the mission has been extended to cover the twenty first solar cycle for which an intense sun spot maximum is predicted. The spacecraft configuration, the onboard systems, the requirements of the scientific experiments, and the operational aspects of the mission are discussed.
Kehr, J.↗
The Helios solar probes science summaries
The principal results of the Helios investigations through the first five years of the missions are presented.
Trainor, J. H.↗
An extended investigation of Helios 1 and 2 observations - The interplanetary magnetic field between 0.3 and 1 AU
Helios 1 and 2 spacecraft allowed a detailed investigation of the radial dependence of the interplanetary magnetic field components between 0.3 and 1 AU. The behavior of the radial component is in a very good agreement with Parker's model (approximately equal to the inverse square of the heliocentric distance) and the azimuthal component also shows a radial dependence which is close to theoretical predictions (approximately equal to the inverse of the heliocentric distance). Experimental results for the normal component and for the field magnitude are consistent with those from previous investigations. The relative amplitude of the directional fluctuations with periods less than 12 hr is essentially independent of heliocentric distance, while their power decreases approximately as the inverse cube of the heliocentric distance without any appreciable difference between higher and lower velocity regimes.
Mariani, F.↗
Interplanetary particles and fields, November 22 to December 6, 1977 - Helios, Voyager and Imp observations between 0.6 and 1.6 AU
The paper presents a wealth of data obtained at approximately 0.6, 1, and 1.6 AU by Helios 1 and 2, Voyager 1 and 2, and Imp 7 and 8, describing the evolution and interactions of particles, flows, and fields in the period 22 November to 6 December 1977. Three flow systems were observed in the period under consideration: (1) a corotating stream and a stream interface associated with a coronal hole; (2) a shock wave and an energetic particle event associated with a 2B flare; and (3) an isolated shock wave of uncertain origin. These phenomena are discussed in some detail.
Burlaga, L.↗
Interplanetary pitch angle scattering and coronal transport of solar energetic particles - New information from Helios
In the present paper, solar particle data from the Kiel experiment on Helios 2 at 0.5 AU are compared with the predictions of a model describing the coherent interplanetary transport of neutral particles. Good agreement is established for an event in March 1978 involving 0.5 MeV electrons and 5 MeV protons.
Bieber, J. W.↗