Radiation zone passages occur between the end of one orbit and the beginning of the next. During radiation zone passages, no Chandra observations are possible due to the high particle background and the need to protect ACIS. For observations which must be tightly constrained, observers may wish to check projected estimates of usable orbit intervals (and their unusable complement during the radiation zone).
The begin and end orbit times listed below are conservative guesses as to the actual radiation zone entry and exit times. They are found from the perigee times given in a predictive ephemeris in the following manner:
Actual useful segments of orbits are likely to be somewhat longer, but should not be shorter than the times listed here. However, the perigee times will be less accurate as time increases from the creation date. At one year after the creation date, the perigee times are expected to be about 10 minutes off from the actual perigee time.
The date/times are provided here in Calendar (UTC) format. To convert to other date formats, please see the Date Conversion Tool page.
Earlier orbital event times can be accessed on our archived orbits pages.
| Orbit | Begin Orbit | End Orbit |
|---|---|---|
| 2231 | 2015 Oct 01 00:58:02.53 | 2015 Oct 02 20:25:32.43 |
| 2232 | 2015 Oct 03 16:25:32.43 | 2015 Oct 05 11:52:57.29 |
| 2233 | 2015 Oct 06 07:52:57.29 | 2015 Oct 08 03:20:26.39 |
| 2234 | 2015 Oct 08 23:20:26.39 | 2015 Oct 10 18:48:22.52 |
| 2235 | 2015 Oct 11 14:48:22.52 | 2015 Oct 13 10:17:02.05 |
| 2236 | 2015 Oct 14 06:17:02.05 | 2015 Oct 16 01:46:12.57 |
| 2237 | 2015 Oct 16 21:46:12.57 | 2015 Oct 18 17:15:17.97 |
| 2238 | 2015 Oct 19 13:15:17.97 | 2015 Oct 21 08:43:40.25 |
| 2239 | 2015 Oct 22 04:43:40.25 | 2015 Oct 24 00:11:01.16 |
| 2240 | 2015 Oct 24 20:11:01.16 | 2015 Oct 26 15:37:59.55 |
| 2241 | 2015 Oct 27 11:37:59.55 | 2015 Oct 29 07:05:34.40 |
| 2242 | 2015 Oct 30 03:05:34.40 | 2015 Oct 31 22:33:13.10 |
| 2243 | 2015 Nov 01 18:33:13.10 | 2015 Nov 03 14:00:48.09 |
| 2244 | 2015 Nov 04 10:00:48.09 | 2015 Nov 06 05:28:51.55 |
| 2245 | 2015 Nov 07 01:28:51.55 | 2015 Nov 08 20:57:35.46 |
| 2246 | 2015 Nov 09 16:57:35.46 | 2015 Nov 11 12:26:52.60 |
| 2247 | 2015 Nov 12 08:26:52.60 | 2015 Nov 14 03:56:15.93 |
| 2248 | 2015 Nov 14 23:56:15.93 | 2015 Nov 16 19:25:09.06 |
| 2249 | 2015 Nov 17 15:25:09.06 | 2015 Nov 19 10:53:01.93 |
| 2250 | 2015 Nov 20 06:53:01.93 | 2015 Nov 22 02:20:21.29 |
| 2251 | 2015 Nov 22 22:20:21.29 | 2015 Nov 24 17:47:55.07 |
| 2252 | 2015 Nov 25 13:47:55.07 | 2015 Nov 27 09:15:46.97 |
| 2253 | 2015 Nov 28 05:15:46.97 | 2015 Nov 30 00:43:26.26 |
| 2254 | 2015 Nov 30 20:43:26.26 | 2015 Dec 02 16:11:20.05 |
| 2255 | 2015 Dec 03 12:11:20.05 | 2015 Dec 05 07:39:54.04 |
| 2256 | 2015 Dec 06 03:39:54.04 | 2015 Dec 07 23:09:05.02 |
| 2257 | 2015 Dec 08 19:09:05.02 | 2015 Dec 10 14:38:32.58 |
| 2258 | 2015 Dec 11 10:38:32.58 | 2015 Dec 13 06:07:33.49 |
| 2259 | 2015 Dec 14 02:07:33.49 | 2015 Dec 15 21:35:40.10 |
| 2260 | 2015 Dec 16 17:35:40.10 | 2015 Dec 18 13:03:02.01 |
| 2261 | 2015 Dec 19 09:03:02.01 | 2015 Dec 21 04:30:23.66 |
| 2262 | 2015 Dec 22 00:30:23.66 | 2015 Dec 23 19:58:10.14 |
| 2263 | 2015 Dec 24 15:58:10.14 | 2015 Dec 26 11:25:44.40 |
| 2264 | 2015 Dec 27 07:25:44.40 | 2015 Dec 29 02:53:17.28 |
| 2265 | 2015 Dec 29 22:53:17.28 | 2015 Dec 31 18:21:26.85 |
| 2266 | 2016 Jan 01 14:21:26.85 | 2016 Jan 03 09:50:12.88 |
| 2267 | 2016 Jan 04 05:50:12.88 | 2016 Jan 06 01:19:21.15 |
| 2268 | 2016 Jan 06 21:19:21.15 | 2016 Jan 08 16:48:19.84 |
| 2269 | 2016 Jan 09 12:48:19.84 | 2016 Jan 11 08:16:26.48 |
| 2270 | 2016 Jan 12 04:16:26.48 | 2016 Jan 13 23:43:41.13 |
| 2271 | 2016 Jan 14 19:43:41.13 | 2016 Jan 16 15:10:42.88 |
| 2272 | 2016 Jan 17 11:10:42.88 | 2016 Jan 19 06:38:09.81 |
| 2273 | 2016 Jan 20 02:38:09.81 | 2016 Jan 21 22:05:39.50 |
| 2274 | 2016 Jan 22 18:05:39.50 | 2016 Jan 24 13:32:54.46 |
| 2275 | 2016 Jan 25 09:32:54.46 | 2016 Jan 27 05:00:32.97 |
| 2276 | 2016 Jan 28 01:00:32.97 | 2016 Jan 29 20:28:51.31 |
| 2277 | 2016 Jan 30 16:28:51.31 | 2016 Feb 01 11:57:37.93 |
| 2278 | 2016 Feb 02 07:57:37.93 | 2016 Feb 04 03:26:25.90 |
| 2279 | 2016 Feb 04 23:26:25.90 | 2016 Feb 06 18:54:37.48 |
| 2280 | 2016 Feb 07 14:54:37.48 | 2016 Feb 09 10:21:49.47 |
| 2281 | 2016 Feb 10 06:21:49.47 | 2016 Feb 12 01:48:30.94 |
| 2282 | 2016 Feb 12 21:48:30.94 | 2016 Feb 14 17:15:36.21 |
| 2283 | 2016 Feb 15 13:15:36.21 | 2016 Feb 17 08:42:56.86 |
| 2284 | 2016 Feb 18 04:42:56.86 | 2016 Feb 20 00:10:04.63 |
| 2285 | 2016 Feb 20 20:10:04.63 | 2016 Feb 22 15:37:27.25 |
| 2286 | 2016 Feb 23 11:37:27.25 | 2016 Feb 25 07:05:28.80 |
| 2287 | 2016 Feb 26 03:05:28.80 | 2016 Feb 27 22:34:03.69 |
| 2288 | 2016 Feb 28 18:34:03.69 | 2016 Mar 01 14:02:51.88 |
| 2289 | 2016 Mar 02 10:02:51.88 | 2016 Mar 04 05:31:16.33 |
| 2290 | 2016 Mar 05 01:31:16.33 | 2016 Mar 06 20:58:45.19 |
| 2291 | 2016 Mar 07 16:58:45.19 | 2016 Mar 09 12:25:31.14 |
| 2292 | 2016 Mar 10 08:25:31.14 | 2016 Mar 12 03:52:24.51 |
| 2293 | 2016 Mar 12 23:52:24.51 | 2016 Mar 14 19:19:43.76 |
| 2294 | 2016 Mar 15 15:19:43.76 | 2016 Mar 17 10:46:60.00 |
| 2295 | 2016 Mar 18 06:46:60.00 | 2016 Mar 20 02:14:24.02 |
| 2296 | 2016 Mar 20 22:14:24.02 | 2016 Mar 22 17:42:26.61 |
| 2297 | 2016 Mar 23 13:42:26.61 | 2016 Mar 25 09:11:04.99 |
| 2298 | 2016 Mar 26 05:11:04.99 | 2016 Mar 28 00:40:02.69 |
| 2299 | 2016 Mar 28 20:40:02.69 | 2016 Mar 30 16:08:46.88 |
| 2300 | 2016 Mar 31 12:08:46.88 | 2016 Apr 02 07:36:52.35 |
| 2301 | 2016 Apr 03 03:36:52.35 | 2016 Apr 04 23:04:03.67 |
| 2302 | 2016 Apr 05 19:04:03.67 | 2016 Apr 07 14:30:57.96 |
| 2303 | 2016 Apr 08 10:30:57.96 | 2016 Apr 10 05:58:19.83 |
| 2304 | 2016 Apr 11 01:58:19.83 | 2016 Apr 12 21:25:43.99 |
| 2305 | 2016 Apr 13 17:25:43.99 | 2016 Apr 15 12:53:14.33 |
| 2306 | 2016 Apr 16 08:53:14.33 | 2016 Apr 18 04:21:20.11 |
| 2307 | 2016 Apr 19 00:21:20.11 | 2016 Apr 20 19:50:02.33 |
| 2308 | 2016 Apr 21 15:50:02.33 | 2016 Apr 23 11:19:09.41 |
| 2309 | 2016 Apr 24 07:19:09.41 | 2016 Apr 26 02:48:13.21 |
| 2310 | 2016 Apr 26 22:48:13.21 | 2016 Apr 28 18:16:43.86 |
| 2311 | 2016 Apr 29 14:16:43.86 | 2016 May 01 09:44:29.81 |
| 2312 | 2016 May 02 05:44:29.81 | 2016 May 04 01:11:40.15 |
| 2313 | 2016 May 04 21:11:40.15 | 2016 May 06 16:39:03.86 |
| 2314 | 2016 May 07 12:39:03.86 | 2016 May 09 08:06:37.30 |
| 2315 | 2016 May 10 04:06:37.30 | 2016 May 11 23:34:06.34 |
| 2316 | 2016 May 12 19:34:06.34 | 2016 May 14 15:02:05.85 |
| 2317 | 2016 May 15 11:02:05.85 | 2016 May 17 06:30:45.02 |
| 2318 | 2016 May 18 02:30:45.02 | 2016 May 19 21:56:15.00 |
| 2319 | 2016 May 20 17:56:15.00 | 2016 May 22 13:29:05.77 |
| 2320 | 2016 May 23 09:29:05.77 | 2016 May 25 04:57:53.40 |
| 2321 | 2016 May 26 00:57:53.40 | 2016 May 27 20:25:55.67 |
| 2322 | 2016 May 28 16:25:55.67 | 2016 May 30 11:53:20.01 |
| 2323 | 2016 May 31 07:53:20.01 | 2016 Jun 02 03:20:41.10 |
| 2324 | 2016 Jun 02 23:20:41.10 | 2016 Jun 04 18:48:16.44 |
| 2325 | 2016 Jun 05 14:48:16.44 | 2016 Jun 07 10:15:37.66 |
| 2326 | 2016 Jun 08 06:15:37.66 | 2016 Jun 10 01:43:18.64 |
| 2327 | 2016 Jun 10 21:43:18.64 | 2016 Jun 12 17:11:41.15 |
| 2328 | 2016 Jun 13 13:11:41.15 | 2016 Jun 15 08:40:36.28 |
| 2329 | 2016 Jun 16 04:40:36.28 | 2016 Jun 18 00:09:42.55 |
| 2330 | 2016 Jun 18 20:09:42.55 | 2016 Jun 20 15:38:29.45 |
| 2331 | 2016 Jun 21 11:38:29.45 | 2016 Jun 23 07:06:31.74 |
| 2332 | 2016 Jun 24 03:06:31.74 | 2016 Jun 25 22:33:58.09 |
| 2333 | 2016 Jun 26 18:33:58.09 | 2016 Jun 28 14:01:10.57 |
| 2334 | 2016 Jun 29 10:01:10.57 | 2016 Jul 01 05:28:37.82 |
| 2335 | 2016 Jul 02 01:28:37.82 | 2016 Jul 03 20:55:57.79 |
| 2336 | 2016 Jul 04 16:55:57.79 | 2016 Jul 06 12:23:16.75 |
| 2337 | 2016 Jul 07 08:23:16.75 | 2016 Jul 09 03:51:12.08 |
| 2338 | 2016 Jul 09 23:51:12.08 | 2016 Jul 11 19:19:48.38 |
| 2339 | 2016 Jul 12 15:19:48.38 | 2016 Jul 14 10:48:41.30 |
| 2340 | 2016 Jul 15 06:48:41.30 | 2016 Jul 17 02:17:22.84 |
| 2341 | 2016 Jul 17 22:17:22.84 | 2016 Jul 19 17:45:29.41 |
| 2342 | 2016 Jul 20 13:45:29.41 | 2016 Jul 22 09:12:50.63 |
| 2343 | 2016 Jul 23 05:12:50.63 | 2016 Jul 25 00:39:51.31 |
| 2344 | 2016 Jul 25 20:39:51.31 | 2016 Jul 27 16:07:06.85 |
| 2345 | 2016 Jul 28 12:07:06.85 | 2016 Jul 30 07:34:21.57 |
| 2346 | 2016 Jul 31 03:34:21.57 | 2016 Aug 01 23:01:31.74 |
| 2347 | 2016 Aug 02 19:01:31.74 | 2016 Aug 04 14:29:03.54 |
| 2348 | 2016 Aug 05 10:29:03.54 | 2016 Aug 07 05:57:18.65 |
| 2349 | 2016 Aug 08 01:57:18.65 | 2016 Aug 09 21:26:00.10 |
| 2350 | 2016 Aug 10 17:26:00.10 | 2016 Aug 12 12:54:38.84 |
| 2351 | 2016 Aug 13 08:54:38.84 | 2016 Aug 15 04:22:50.75 |
| 2352 | 2016 Aug 16 00:22:50.75 | 2016 Aug 17 19:50:14.89 |
| 2353 | 2016 Aug 18 15:50:14.89 | 2016 Aug 20 11:17:11.29 |
| 2354 | 2016 Aug 21 07:17:11.29 | 2016 Aug 23 02:44:13.53 |
| 2355 | 2016 Aug 23 22:44:13.53 | 2016 Aug 25 18:11:26.36 |
| 2356 | 2016 Aug 26 14:11:26.36 | 2016 Aug 28 09:38:34.81 |
| 2357 | 2016 Aug 29 05:38:34.81 | 2016 Aug 31 01:05:57.51 |
| 2358 | 2016 Aug 31 21:05:57.51 | 2016 Sep 02 16:34:04.08 |
| 2359 | 2016 Sep 03 12:34:04.08 | 2016 Sep 05 08:02:43.94 |
| 2360 | 2016 Sep 06 04:02:43.94 | 2016 Sep 07 23:31:25.02 |
| 2361 | 2016 Sep 08 19:31:25.02 | 2016 Sep 10 14:59:51.85 |
| 2362 | 2016 Sep 11 10:59:51.85 | 2016 Sep 13 06:27:36.94 |
| 2363 | 2016 Sep 14 02:27:36.94 | 2016 Sep 15 21:54:42.81 |
| 2364 | 2016 Sep 16 17:54:42.81 | 2016 Sep 18 13:21:42.70 |
| 2365 | 2016 Sep 19 09:21:42.70 | 2016 Sep 21 04:48:56.85 |
| 2366 | 2016 Sep 22 00:48:56.85 | 2016 Sep 23 20:16:08.41 |
| 2367 | 2016 Sep 24 16:16:08.41 | 2016 Sep 26 11:43:36.95 |
| 2368 | 2016 Sep 27 07:43:36.95 | 2016 Sep 29 03:11:40.83 |
| 2369 | 2016 Sep 29 23:11:40.83 | 2016 Oct 01 18:40:17.27 |
| 2370 | 2016 Oct 02 14:40:17.27 | 2016 Oct 04 10:09:13.82 |
| 2371 | 2016 Oct 05 06:09:13.82 | 2016 Oct 07 01:37:53.74 |
| 2372 | 2016 Oct 07 21:37:53.74 | 2016 Oct 09 17:06:01.50 |
| 2373 | 2016 Oct 10 13:06:01.50 | 2016 Oct 12 08:33:33.26 |
| 2374 | 2016 Oct 13 04:33:33.26 | 2016 Oct 15 00:00:40.57 |
| 2375 | 2016 Oct 15 20:00:40.57 | 2016 Oct 17 15:27:57.26 |
| 2376 | 2016 Oct 18 11:27:57.26 | 2016 Oct 20 06:55:12.81 |
| 2377 | 2016 Oct 21 02:55:12.81 | 2016 Oct 22 22:22:37.72 |
| 2378 | 2016 Oct 23 18:22:37.72 | 2016 Oct 25 13:50:38.04 |
| 2379 | 2016 Oct 26 09:50:38.04 | 2016 Oct 28 05:19:19.27 |
| 2380 | 2016 Oct 29 01:19:19.27 | 2016 Oct 30 20:48:19.80 |
| 2381 | 2016 Oct 31 16:48:19.80 | 2016 Nov 02 12:17:11.39 |
| 2382 | 2016 Nov 03 08:17:11.39 | 2016 Nov 05 03:45:39.41 |
| 2383 | 2016 Nov 05 23:45:39.41 | 2016 Nov 07 19:13:31.79 |
| 2384 | 2016 Nov 08 15:13:31.79 | 2016 Nov 10 10:40:51.63 |
| 2385 | 2016 Nov 11 06:40:51.63 | 2016 Nov 13 02:08:10.83 |
| 2386 | 2016 Nov 13 22:08:10.83 | 2016 Nov 15 17:35:29.46 |
| 2387 | 2016 Nov 16 13:35:29.46 | 2016 Nov 18 09:02:43.89 |
| 2388 | 2016 Nov 19 05:02:43.89 | 2016 Nov 21 00:30:31.56 |
| 2389 | 2016 Nov 21 20:30:31.56 | 2016 Nov 23 15:59:01.79 |
| 2390 | 2016 Nov 24 11:59:01.79 | 2016 Nov 26 07:27:57.67 |
| 2391 | 2016 Nov 27 03:27:57.67 | 2016 Nov 28 22:56:52.49 |
| 2392 | 2016 Nov 29 18:56:52.49 | 2016 Dec 01 14:25:24.22 |
| 2393 | 2016 Dec 02 10:25:24.22 | 2016 Dec 04 05:53:20.32 |
| 2394 | 2016 Dec 05 01:53:20.32 | 2016 Dec 06 21:20:50.48 |
| 2395 | 2016 Dec 07 17:20:50.48 | 2016 Dec 09 12:48:06.45 |
| 2396 | 2016 Dec 10 08:48:06.45 | 2016 Dec 12 04:15:21.30 |
| 2397 | 2016 Dec 13 00:15:21.30 | 2016 Dec 14 19:42:28.98 |
| 2398 | 2016 Dec 15 15:42:28.98 | 2016 Dec 17 11:09:44.59 |
| 2399 | 2016 Dec 18 07:09:44.59 | 2016 Dec 20 02:37:52.89 |
| 2400 | 2016 Dec 20 22:37:52.89 | 2016 Dec 22 18:06:34.81 |
| 2401 | 2016 Dec 23 14:06:34.81 | 2016 Dec 25 09:35:17.92 |
| 2402 | 2016 Dec 26 05:35:17.92 | 2016 Dec 28 01:03:44.74 |
| 2403 | 2016 Dec 28 21:03:44.74 | 2016 Dec 30 16:31:39.31 |
| 2404 | 2016 Dec 31 12:31:39.31 | 2017 Jan 02 07:59:04.39 |
| 2405 | 2017 Jan 03 03:59:04.39 | 2017 Jan 04 23:26:16.70 |
| 2406 | 2017 Jan 05 19:26:16.70 | 2017 Jan 07 14:53:27.65 |
| 2407 | 2017 Jan 08 10:53:27.65 | 2017 Jan 10 06:20:30.66 |
| 2408 | 2017 Jan 11 02:20:30.66 | 2017 Jan 12 21:47:32.56 |
| 2409 | 2017 Jan 13 17:47:32.56 | 2017 Jan 15 13:15:13.90 |
| 2410 | 2017 Jan 16 09:15:13.90 | 2017 Jan 18 04:43:33.47 |
| 2411 | 2017 Jan 19 00:43:33.47 | 2017 Jan 20 20:12:10.87 |
| 2412 | 2017 Jan 21 16:12:10.87 | 2017 Jan 23 11:40:34.61 |
| 2413 | 2017 Jan 24 07:40:34.61 | 2017 Jan 26 03:08:27.71 |
| 2414 | 2017 Jan 26 23:08:27.71 | 2017 Jan 28 18:35:51.75 |
| 2415 | 2017 Jan 29 14:35:51.75 | 2017 Jan 31 10:03:00.69 |
| 2416 | 2017 Feb 01 06:03:00.69 | 2017 Feb 03 01:30:04.42 |
| 2417 | 2017 Feb 03 21:30:04.42 | 2017 Feb 05 16:57:11.15 |
| 2418 | 2017 Feb 06 12:57:11.15 | 2017 Feb 08 08:24:11.11 |
| 2419 | 2017 Feb 09 04:24:11.11 | 2017 Feb 10 23:51:34.37 |
| 2420 | 2017 Feb 11 19:51:34.37 | 2017 Feb 13 15:19:45.60 |
| 2421 | 2017 Feb 14 11:19:45.60 | 2017 Feb 16 06:48:19.84 |
| 2422 | 2017 Feb 17 02:48:19.84 | 2017 Feb 18 22:16:46.44 |
| 2423 | 2017 Feb 19 18:16:46.44 | 2017 Feb 21 13:44:53.27 |
| 2424 | 2017 Feb 22 09:44:53.27 | 2017 Feb 24 05:12:24.35 |
| 2425 | 2017 Feb 25 01:12:24.35 | 2017 Feb 26 20:39:36.86 |
| 2426 | 2017 Feb 27 16:39:36.86 | 2017 Mar 01 12:06:46.39 |
| 2427 | 2017 Mar 02 08:06:46.39 | 2017 Mar 04 03:33:55.58 |
| 2428 | 2017 Mar 04 23:33:55.58 | 2017 Mar 06 19:01:04.27 |
| 2429 | 2017 Mar 07 15:01:04.27 | 2017 Mar 09 10:28:29.63 |
| 2430 | 2017 Mar 10 06:28:29.63 | 2017 Mar 12 01:56:35.33 |
| 2431 | 2017 Mar 12 21:56:35.33 | 2017 Mar 14 17:25:14.35 |
| 2432 | 2017 Mar 15 13:25:14.35 | 2017 Mar 17 08:53:56.29 |
| 2433 | 2017 Mar 18 04:53:56.29 | 2017 Mar 20 00:22:18.51 |
| 2434 | 2017 Mar 20 20:22:18.51 | 2017 Mar 22 15:50:11.17 |
| 2435 | 2017 Mar 23 11:50:11.17 | 2017 Mar 25 07:17:39.13 |
| 2436 | 2017 Mar 26 03:17:39.13 | 2017 Mar 27 22:44:50.86 |
| 2437 | 2017 Mar 28 18:44:50.86 | 2017 Mar 30 14:12:06.28 |
| 2438 | 2017 Mar 31 10:12:06.28 | 2017 Apr 02 05:39:18.10 |
Last modified: 12/14/16
