This Mercury 1 figure is preliminary. That being said, it is probably the highest-time-resolution plot of the MVM/CPI data available currently, and it should be temporally accurate to ~0.6 seconds (this is in spacecraft time, S/C time). Please notice that there are spikes in the data (resulting from poor data quality transfer at times) which I will document and edit out sometime soon. When finished, I will provide an original copy and a despiked copy of this data file to the NASA archives. The full data file interval is: ~1859-2345 UT (S/C time), day 88 (March 29), 1974. This plot represents my first attempt to read and display the Mercury 1 encounter CPI raw summary tape data in well over 15 years. I started working with a Fortran program I originally wrote in the mid 1970's. But, because the data file I am now working with was restructured by Gordon Lentz sometime before he sent me a CD containing it in 1995 and because it differs somewhat from the original summary tape data files I worked with in the mid 1970's, I was not sure that I would even get this far. (Unfortunately, both Gordon Lentz, the Data Systems Manager, and John Simpson, the instrument P.I., are now deceased.) About a year ago I provided Ray Walker's Planetary Data System Particles and Fields group with a copy of the data file and the Fortran code, but they were not successful in converting it.
I am currently providing these data and the work needed to generate the converted data file out of a sense of duty to the data itself and to my respect for the scientific integrity of our small team of researchers at the University of Chicago's Laboratory for Astrophysics and Space Research (LASR) in the 1970's who investigated a poorly understood and very difficult to predictably reproduce instrumental problem (electron pileup) and its effect on these unique data. The LASR team was: John Simpson, Tony Tuzzolino, Gordon Lentz, Jim Eraker, Steve Daly, Jim Coates, Murry Perkins, Pete Walpole, and myself.
Mercury appears to possess the only other Earth-like magnetosphere in the solar system. Mercury's magnetosphere is smaller, but in most ways it seems comparable to Earth's magnetosphere, only magnetospheric processes, such as substorms, occur ~30 times more frequently than in Earth's magnetosphere (see e.g., Christon, S.P., A comparison of the Mercury and Earth magnetospheres: Electron measurements and substorm time scales, [Icarus, 71, 3, Sept. 1987, 448-471] and references therein).
My goal is to disseminate information about the energetic charged particle measurements obtained at Mercury by the University of Chicago (U of C) Charged Particle Instrument (CPI).
Recently I generated a hexadecimal dump of the data file and have worked from that listing, a recently found a handwritten description of the data format, and my memory of my earlier work on the code. I had regenerated the data in a similar manner about 18 years ago, but have not touched any of it since then. I thought I had lost all of the documentation needed to verify the Fortran code (the data format is explicitly defined in the Fortran code). Here are a few lines of the hexadecimal dump of the data file.
30 30 30 30 33 34 35 36 10 02 EB 21 A0 F1 06 A2 82 21 F0 18 D9 3C 15 22 50 00 30 41 C5 22 E0 F1 06 A2 82 23 30 18 D9 3C 15 23 90 00 30 41 C5 24 20 F1 06 A2 82 24 70 18 D9 3C 15 24 83 E0 00 00 01 24 D0 00 30 41 C5 25 60 F1 06 A2 82 25 B0 18 D9 3C 15 26 10 00 30 41 C5 26 41 6E 0E 49 04 26 A0 F1 06 A2 82 26 F0 18 D9 3C 15 27 50 00 30 41 C5 27 E0 F1 06 A2 82 28 30 18 D9 3C 15 28 90 00 30 41 C5 29 20 F1 06 A2 82 29 70 18 D9 3C 15 29 D0 00 30 41 C5 2A 60 F1 06 A2 82 2A B0 18 D9 3C
By the time I finish with these MVM-Mercury pages, you will understand the procedure I have used to reconstruct the data. A copy of the C language program I am using will be provided. The program is not listed yet because it is still being written. I am solely responsible for the quality of the end product and I am also solely responsible for any errors introduced. This effort is not supported by any federal or other funding source.
Last updated: November 2004