Heliocentric Potential

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The heliocentric potential enables the program to adjust for changes in galactic radiation levels that occur with changes in solar activity. The program employs the user-entered flight date to select the appropriate heliocentric potential from its database. The program will prompt the user in entering heliocentric potentials for dates not already in the database. There may be a lag of up to one month in availability of heliocentric potential data on our Web site.

To estimate flight doses during the current month, use the most recent heliocentric potential available. Do not use a heliocentric potential more than two months removed from the month of interest. Flight doses for specific flight profiles normally change very little in a couple of months. To compare CARI-6 or CARI-6M dose estimates with instrument measurements, we recommend using heliocentric potentials appropriate for the days or hours of the measurements. We will provide these heliocentric potentials on request.

Please email us if you would like additional information about Heliocentric Potentials.

Also, please see our Office of Aerospace Medicine technical report entitled Ionizing Radiation in Earth's Atmosphere and in Space Near Earth (PDF)

The values in the table shown below are available in this MS Excel file (MS Excel).

Recent and Historic Heliocentric Potentials (shown in megavolts)

Month of Flight	2013	2012	2011	2010	2009	2008	2007	2006	2005	2004
January	505	466	362	244	256	298	374	458	723	895
February	485	508	357	296	252	312	379	431	596	755
March	517	593	392	303	238	321	340	380	566	654
April		466	460	335	224	312	314	389	536	617
May		460	420	337	226	321	305	379	631	585
June		517	517	349	228	323	300	392	557	592
July		635	485	357	236	319	319	405	594	651
August		612	477	372	238	305	312	405	626	617
September		555	483	364	228	276	300	397	727	587
October		546	497	379	220	285	291	357	537	503
November		540	463	367	244	270	307	374	489	605
December		505	423	377	234	266	287	436	494	583
For the year		531	444	337	234	298	316	397	586	628

Heliocentric potentials for recent months (last 12 months) are preliminary. The data above is based on ground level neutron measurements provided by Dr. Eduard Vashenyuk of the Apatity Cosmic Ray Station of the Polar Geophysical Institute, Russia.