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instead defined touchdown as "Sol 1". Generally speaking, the choice between counting from Sol 0 or Sol 1 has been made so that Sol 1 would be the first sol with "meaningful" or "useful" lander operations. Thus, landers that touched down late in the
Martian day have begun their sol count at 0, while
261:
Mission of 2003. It was eventually picked up and used by the press. Other neologisms include "tosol" (for "today" on Mars), as well as one of three Mars versions of "tomorrow": "nextersol", "morrowsol", or "solmorrow". NASA planners coined the term "soliday" at least as far back as 2012 to refer to
171:
168:
169:
256:
The word "yestersol" was coined by the NASA Mars operations team early during the MER mission to refer to the previous sol (the Mars version of "yesterday"), and came into fairly wide use within that organization during the
170:
315:
mission, a small watchmaker's store created mechanical watches for the mission crew that kept Mars time with no more than 10 seconds difference per Earth-day. In 2022, it was reported that the watchmaker
151:
of Mars—its rotation compared to the fixed stars—is 24 hours, 37 minutes and 22.66 seconds. The solar day lasts longer because Mars's rotation is the same direction as its orbital motion.
105:. A sol is the apparent interval between two successive returns of the Sun to the same meridian (sundial time) as seen by an observer on Mars. It is one of several units for
236:
lander missions to Mars have twice occurred in pairs, no effort was made to synchronize the sol counts of the two landers within each pair. Thus, for example, although
167:
402:
478:
248:
were sent to operate simultaneously on Mars, each counted its landing date as "Sol 1", putting their calendars approximately 21 sols out of sync.
980:
1119:
1104:
835:
1333:
920:
397:
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spacecraft lander begins operations on Mars, the passing
Martian days (sols) have been tracked using a simple numerical count. The two
1578:
1573:
523:
1202:
855:
895:
732:
689:
428:"Accurate analytic representations of solar time and seasons on Mars with applications to the Pathfinder/Surveyor missions"
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540:
1308:
432:
296:" which compensates for the time difference between a Sol and an Earth day. This follows the method previously given by
293:
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1538:
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805:
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51:
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1303:
1174:
1060:
947:
183:
148:
65:
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1500:
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747:
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258:
225:
337:
112:
A sol is slightly longer than an Earth day. It is approximately 24 hours, 39 minutes, 35 seconds long. A
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1328:
1139:
1087:
1082:
1065:
942:
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31:
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113:
106:
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for 39 minutes and 40 seconds before resuming their timekeeping. This creates something like a "
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is approximately 668.6 sols, equivalent to approximately 687 Earth days or 1.88 Earth years.
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1109:
1020:
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449:
368:
1632:
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274:, one question that arose was "how does one convert a Sol to standard Earth time?" In the
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147:— is 24 hours, 39 minutes and 35.244 seconds, equivalent to 1.02749125 Earth days. The
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715:
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1553:
1187:
1050:
372:
94:
516:
The Mighty Mars Rovers: The
Incredible Adventures of Spirit and Opportunity
17:
1339:
1320:
1192:
317:
289:
1149:
830:
288:, the Mars settlers use traditional Earth watches that stop ticking at
211:
78:
454:
427:
393:"Technical Notes on Mars Solar Time as Adopted by the Mars24 Sunclock"
143:
The average duration of the day-night cycle on Mars — i.e., a
Martian
875:
262:
days off due to time phasing or the syncing of planetary schedules.
1700:
647:"New Omega Marstimer watch keeps time on Earth and the Red Planet"
164:
90:
698:
233:
191:
128:
98:
671:
320:
had begun to sell digital-analog hybrid watches to the public.
229:
those that touch down early in the day began their count at 1.
144:
38:
351:
Snyder, Conway W. (1979). "The extended mission of Viking".
220:
rover projects all counted the sol of touchdown as "Sol 0".
493:"Phoenix Mars Mission - Mission - Mission Phases - On Mars"
667:
574:[Mars: 'yestersol', 'tosol', and 'solmorrow'].
1677:
1566:
1517:
1499:
1443:
1434:
1414:
1398:
1319:
1271:
1224:
1215:
1173:
961:
854:
756:
723:
714:
391:Allison, Michael; Schmunk, Robert (30 June 2015).
578:(in Spanish). Madrid, Spain: Unidad Editorial S.A
541:"MSL? EDL? A guide to NASA's Mars rover lingo"
683:
403:National Aeronautics and Space Administration
8:
386:
384:
382:
182:on sol 1037 of its mission (20 January 2024
572:"Marte: 'yestersol', 'tosol' y 'solmorrow'"
570:MartĂnez-FrĂas, JesĂşs (28 September 2002).
495:. Phoenix.lpl.arizona.edu. 29 February 2008
131:when, for example, scheduling the use of a
1440:
1221:
720:
690:
676:
668:
469:Belloni, Mario; Timberlake, Todd (2014).
453:
421:
419:
479:American Association of Physics Teachers
1684:
329:
119:The sol was adopted in 1976 during the
7:
600:. an.rsl.wustl.edu. 31 October 2012
426:Allison, Michael (15 August 1997).
398:Goddard Institute for Space Studies
25:
471:"Sidereal and Solar Day JS Model"
1735:
1723:
1711:
1699:
1687:
1660:
1649:
1648:
598:"MSL abbreviations and acronyms"
178:, as captured by the Mars rover
155:Usage in Mars lander timekeeping
64:
50:
558:Yesterday on Mars is yestersol.
539:Chang, Alicia (3 August 2012).
353:Journal of Geophysical Research
27:Solar day: unit of time on Mars
620:"Watchmaker With Time to Lose"
1:
546:The Christian Science Monitor
1105:Recurring slope lineae (RSL)
645:Pearlman, Robert Z. (2022).
433:Geophysical Research Letters
1539:Inspiration Mars Foundation
624:JPL Mars Exploration Rovers
176:Transit of Deimos from Mars
1794:
1574:Artificial objects on Mars
158:
149:sidereal rotational period
36:
29:
1643:
1591:List of films set on Mars
1406:C/2013 A1 (Siding Spring)
1203:Classical albedo features
705:
514:Rusch, Elizabeth (2012).
1509:List of missions to Mars
37:Not to be confused with
1667:Solar System portal
373:10.1029/JB084iB14p07917
270:Considering a possible
226:Mars Exploration Rovers
204:Mars Science Laboratory
1281:Solar eclipses on Mars
1140:"Swiss cheese" feature
996:Concentric crater fill
259:Mars Exploration Rover
187:
121:Viking Lander missions
174:
1481:Permanent settlement
286:Kim Stanley Robinson
272:colonization of Mars
30:For other uses, see
1623:Timekeeping on Mars
1300:Planetary transits
1285:Satellite transits
1198:Observation history
1046:Lobate debris apron
446:1997GeoRL..24.1967A
365:1979JGR....84.7917S
161:Timekeeping on Mars
107:timekeeping on Mars
93:word for sun) is a
89:(borrowed from the
77:Images captured by
1778:1976 introductions
359:(B14): 7917–7933.
300:in his 1964 novel
188:
1675:
1674:
1628:Sol (day on Mars)
1596:Martian scientist
1579:Memorials on Mars
1562:
1561:
1533:The Case for Mars
1430:
1429:
1211:
1210:
1145:Terrain softening
1110:Ring mold craters
1078:North Polar Basin
1001:Dark slope streak
846:Vastitas Borealis
743:Dust devil tracks
455:10.1029/97GL01950
440:(16): 1967–1970.
303:Martian Time-Slip
172:
16:(Redirected from
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1526:The Mars Project
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1083:Ocean hypothesis
933:Outflow channels
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338:"Mars' Calendar"
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1633:Darian calendar
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1315:
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1261:Voltaire crater
1239:Stickney crater
1207:
1169:
1011:Fretted terrain
957:
857:
850:
811:Sinus Meridiani
796:Planum Australe
771:Cerberus (Mars)
752:
710:
708:Outline of Mars
701:
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276:science fiction
268:
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222:Mars Pathfinder
165:
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127:mainly used by
125:measure of time
84:
83:
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81:
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73:
72:
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60:
59:
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57:Sunrise on Mars
55:
42:
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22:
15:
12:
11:
5:
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1544:Mars Institute
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1120:Seasonal flows
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1115:Rootless cones
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943:Valley network
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928:Observed rocks
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841:Ultimi Scopuli
838:
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821:Terra Cimmeria
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525:978-0547822808
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298:Philip K. Dick
267:
264:
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196:Viking landers
159:Main article:
156:
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140:
137:
76:
75:
71:Sunset on Mars
70:
63:
62:
61:
56:
49:
48:
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26:
24:
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6:
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2:
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1763:Units of time
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1506:
1504:
1502:
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1477:
1476:Human mission
1474:
1472:
1471:Sample return
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1334:Mars-crossers
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1150:Tharsis bulge
1148:
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1088:Ore resources
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987:
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981:Chaos terrain
979:
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971:Brain terrain
969:
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886:Chaos terrain
884:
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832:
829:
827:
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817:
814:
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809:
807:
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802:
801:Planum Boreum
799:
797:
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791:Olympia Undae
789:
787:
784:
782:
781:Eridania Lake
779:
777:
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294:witching hour
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101:; that is, a
100:
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88:
80:
67:
53:
44:
40:
33:
19:
1627:
1613:Life on Mars
1608:Flag of Mars
1549:Mars Society
1531:
1524:
1491:Terraforming
1486:Colonization
1256:Swift crater
1098:polar wander
826:Terra Sabaea
766:Arabia Terra
654:. Retrieved
650:
640:
628:. Retrieved
623:
614:
602:. Retrieved
592:
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575:
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557:
550:. Retrieved
544:
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487:
475:compadre.org
474:
464:
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406:. Retrieved
396:
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352:
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332:
310:
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281:Mars trilogy
279:
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231:
224:and the two
217:Perseverance
215:
207:
200:Mars Phoenix
189:
180:Perseverance
142:
118:
114:Martian year
111:
102:
86:
85:
43:
1730:Outer space
1718:Spaceflight
1436:Exploration
1358:5261 Eureka
1026:Groundwater
991:Composition
816:Tempe Terra
806:Quadrangles
733:Circulation
604:19 December
252:Terminology
245:Opportunity
18:Martian day
1752:Categories
1093:Polar caps
1073:Mud cracks
1056:Meteorites
1041:Lava tubes
976:Carbonates
911:Labyrinthi
786:Iani Chaos
725:Atmosphere
630:22 January
324:References
266:Conversion
133:Mars rover
1694:Astronomy
1618:Sub-Earth
1601:Mythology
1554:Mars race
1321:Asteroids
1217:Astronomy
1188:Hesperian
1183:Amazonian
1155:Volcanism
1130:Spherules
1051:Marsquake
1006:Dichotomy
921:by height
916:Mountains
716:Geography
656:3 October
651:Space.com
232:Although
208:Curiosity
123:and is a
95:solar day
1654:Category
1518:Advocacy
1501:Missions
1444:Concepts
1273:Transits
1244:Monolith
1193:Noachian
1165:Yardangs
1061:on Earth
1021:Glaciers
866:"Canals"
858:features
856:Physical
582:23 April
576:El Mundo
309:For the
290:midnight
103:Mars-day
1742:Science
1680:Portals
1586:Fiction
1567:Related
1461:Landing
1456:Orbiter
1415:General
1384:2007 NS
1374:1999 UJ
1364:1998 VF
1353:Trojans
1340:2007 WD
1329:Impacts
1309:Mercury
1175:History
1135:Surface
1066:on Mars
1031:Gullies
1016:Geysers
963:Geology
953:Gravity
948:Valleys
901:Gullies
891:Craters
881:Catenae
876:Canyons
831:Tharsis
776:Cydonia
758:Regions
748:Methane
738:Climate
552:19 June
499:13 July
442:Bibcode
408:13 June
361:Bibcode
278:series
212:InSight
190:When a
79:InSight
1658:
1647:
1399:Comets
1294:Deimos
1289:Phobos
1251:Deimos
1234:Phobos
938:Plains
906:Mensae
896:Fossae
626:. 2014
522:
312:Spirit
239:Spirit
214:, and
206:rover
139:Length
1706:Stars
1466:Rover
1451:Flyby
1422:Orbit
1304:Earth
1226:Moons
1160:Water
1036:Lakes
986:Color
836:Undae
318:Omega
91:Latin
1773:Time
1768:Days
1758:Mars
1125:Soil
870:list
699:Mars
658:2022
632:2015
606:2015
584:2014
554:2020
520:ISBN
501:2012
410:2018
242:and
234:NASA
192:NASA
129:NASA
99:Mars
450:doi
369:doi
284:by
184:UTC
145:day
97:on
87:Sol
39:Sun
32:Sol
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