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Heliocentric Potential

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). Values formatted for use in CAR-6 and CARI-7 for the period 1958 to present are available in this zip file (Zip).

Recent and Historic Heliocentric Potentials (shown in megavolts)
Month of Flight 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011
January 325 275 339 326 349 465 667 579 505 466 362
February 375 254 310 350 319 428 668 628 485 508 357
March 253 255 339 294 418 683 590 517 593 392
April 261 267 286 310 417 647 578 511 466 460
May 253 284 301 306 411 596 545 622 460 420
June 268 274 284 303 409 617 612 642 517 517
July 272 288 293 339 424 572 586 618 635 485
August 276 292 289 375 402 570 499 599 612 477
September 271 274 278 398 392 568 585 577 555 483
October 272 267 263 354 368 536 565 546 546 497
November 276 290 278 319 352 525 604 577 540 463
December 305 296 289 329 346 530 689 622 505 423
For the year 270 286 297 332 402 596 587 565 531 444

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.

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This page was originally published at: https://www.faa.gov/data_research/research/med_humanfacs/aeromedical/radiobiology/heliocentric/