longitude) and were not adjusted as the rovers traveled. (The rovers traveled distances that could make a few seconds difference to local solar time.) The HLST of Spirit is AMT+11:00:04 whereas the LMST at its landing site is AMT+11:41:55. The HLST of Opportunity is AMT-01:01:06 whereas the LMST at its landing site is AMT-00:22:06. Neither rover was likely to ever reach the longitude at which its mission time scale matches local mean time. However, for atmospheric measurements and other science purposes, Local True Solar Time is recorded. Spirit and Opportunity both started their sol counts with Sol 1 on the day of landing, corresponding to MSD 46216 and MSD 46236, respectively. Phoenix The Phoenix lander project specified a mission clock that matched Local Mean Solar Time at the planned landing longitude of 126.65°W (233.35°E). This corresponds to a mission clock of AMT-08:26:36. The actual landing site was 0.900778° (19.8 km) east of that, corresponding to 3 minutes and 36 seconds later in local solar time. The date is kept using a mission clock sol count with the landing occurring on Sol 0, corresponding to MSD 47776 (mission time zone); the landing occurred around 16:35 LMST, which is MSD 47777 01:02 AMT. Curiosity The Curiosity rover project specified a mission clock that matched Local Mean Solar Time at its originally planned landing longitude of 137.42°E. This corresponds to a mission clock of AMT+09:09:40.8. The actual landing site was about 0.02° (1.3 km) east of that, a difference of about 5 seconds in solar time. The local mean solar time is also affected by the rover motion; at 4.6°S, this is about 1 second of time difference for every 246 meters of displacement along the east-west direction. The date is kept using a mission clock sol count with the landing occurring on Sol 0, corresponding to MSD 49269 (mission time zone); the landing occurred around 14:53 LMST (05:53 AMT). InSight The InSight lander project specified a mission clock that matched Local Mean Solar Time at its planned landing site of 135.97°E. This corresponds to a mission clock of AMT+09:03:53. The actual landing site was at 135.623447°E, or 0.346553° (20.5 km) west of the reference longitude, so the lander mission clock is 1 minute and 23 seconds ahead of the actual mean local solar time at the lander location. The date is kept using a mission clock sol count with the landing occurring