Engineering topics

Niedner, M. B.

Publications and source records attributed to Niedner, M. B..

5 records

NASA NTRS1992

The digital archive of the International Halley Watch

The International Halley Watch was established to coordinate, collect, archive, and distribute the scientific data from Comet P/Halley that would be obtained from both the ground and space. This paper describes one of the end products of that effort, namely the IHW Digital Archive. The IHW Digital Archive consists of 26 CD-ROM's containing over 32 gigabytes of data from the 9 IHW disciplines as well as data from the 5 spacecraft missions flown to comet P/Haley and P/Giacobini-Zinner. The total archive contains over 50,000 observations by 1,500 observers from at least 40 countries. The first 24 CD's, which are currently available, contain data from the 9 IHW disciplines. The two remaining CD's will have the spacecraft data and should be available within the next year. A test CD-ROM of these data has been created and is currently under review.

Klinglesmith, D. A., III↗

NASA NTRS1987

The cause of two plasma-tail disconnection events in comet P/Haley during the ICE-Halley radial period

The causes of two plasma-tail disconnection events (DEs), which occurred in Halley's comet on March 20-22 and April 11-12, 1986, during the ICE-Halley radial period, are analyzed using the ICE magnetometer and electron plasma data. It is concluded that the DE of March 20-22 was most likely caused by an IMF polarity reversal. The DE of April 11-12 on the other hand, is attributed to either a compression region in the solar wind, an IMF polarity reversal, or a combination of the two. Assuming that the two DEs are due to frontside reconnection after an IMF reversal, it was estimated that the time period between the onset of reconnection and the final disconnection of the tail is between 0.1 and 0.6 day, suggesting that the average speed at which reconnection proceeds through the cometary magnetic field pile-up region is between 1 and 6 km/sec, or several tenths of the local Alfven speed.

Brosius, J. W.↗

NASA NTRS1986

The Astro-1 mission

The Astro-1 mission was to be launched in March 1986 for an effective duration of 7 days, chosen to overlap spacecraft encounters with Halley's Comet, i.e., Vega-2 (on 9 March) and Giotto (on 13/14 March). The ultraviolet instrument complement while not designed with cometary research as the prime objective, was well suited to the study of comets. The opportunity of an extended mission during the time of the spacecraft encounters of Halley's Comet offered an extraordinary opportunity for a synergistic interaction between the intercept spacecraft, the Earth-orbital Astro-1 mission, and ground-based observations. The addition of visual-wavelength, wide-field cameras would enhance the scientific return of the mission. Loss of Challenger cancelled the mission.

Brandt, J. C.↗

NASA NTRS1986

Observations of Halley's Comet by the Solar Maximum Mission (SMM)

Solar Maximum Mission coronagraph/polarimeter observations of large scale phenomena in Halley's Comet are discussed. Observations of the hydrogen coma with the UV spectrometer are considered. It is concluded that coronograph/polarimeter observations of the disconnection event, in which the entire plasma tail uproots itself from the head of the comet, is convected away in the solar wind at speeds in the 50 to 100 km/sec range (relative to the head), and is replaced by a plasma tail constructed from folding ion-tail rays, are the most interesting.

Niedner, M. B.↗

NASA NTRS1985

The International Cometary Explorer (ICE) mission to comet Giacobini-Zinner (G/Z)

The primary objectives of the International Cometary Explorer (ICE) mission is to provide in situ data on the interaction between solar wind and the atmosphere of the P/Giacobini-Zinner comet (G/Z), making measurements of particles, fields, and waves while passing through the cometary tail of G/Z on September 11, 1985. Following the G/Z tail intercept, the ICE measurements will complement the later upstream measurements obtained by the Comet Halley probe. The major ICE payload includes a vector helium magnetometer, the plasma-wave experiment, the radio-wave experiment, the plasma-electron experiment, and the plasma ion experiment. Other experiments are intended to measure energetic protons, X-rays, low energy to high energy cosmic rays, cosmic ray electrons, and gamma-ray bursts. The ICE measurements of G/Z will be supplemented with ground-based measurements. Schematic diagrams are included.

Brandt, J. C.↗