[X] My Assistant

[Tom O'Reilly]

Does anyone know where I can access a daily ephemeris for the Curiosity landing site? E.g. Sun rise/set, Earth rise/set, MRO/Odyssey/Mars Express transits, etc?

Thanks,
Tom

[elakdawalla]

Marvelous. Thank you!

[jmknapp]

Marvelous. Thank you!

I should point out that that table reckons the start of each sol from midnight LTST (local true solar time), i.e., when the sun actually crosses the meridian. I since gather that the landed missions use LMST (local mean solar time).

From Technical Notes on Mars Solar Time

The Mars Science Laboratory rover project also defined Sol 0 as the solar day on which the lander would touch down. Mission controllers originally specified a mission clock based on the Local Mean Solar Time for a landing site at 137.42°E. Thus, official mission time specified the Sol 0 epoch would start at local mean midnight at 137.42°E prior to landing. However, as the landing site coordinates were later refined, after course corrections were made while MSL Curiosity was in-flight to Mars, and as the rover touched down somewhat "long" of the final target coordinates, the landing site turned out to be at 137.441635°E. Following the example of Phoenix, there was no re-definition of the MSL mission clock to match the actual landing coordinates, and so a difference of a several seconds between LMST at the landing site and mission clock resulted.

LMST diverges from LTST over the year as Mars speeds up and slows down in its eccentric orbit. The difference can be as much as 51 minutes.

Also, as I understand the practice, the local time reference is not adjusted as the rover moves, but is fixed at some "time zone" so to speak, e.g., AMT+11:00:04 for Spirit.

Maybe that table needs to be redone, as soon as I can find out for sure how JPL defines the start of each MSL sol. At least, the sunrise and sunset UTC times are accurate

[mcaplinger]

as soon as I can find out for sure how JPL defines the start of each MSL sol.

See ftp://naif.jpl.nasa.gov/pub/naif/MSL/kern...gc120806_v3.tsc

[jmknapp]

See ftp://naif.jpl.nasa.gov/pub/naif/MSL/kern...gc120806_v3.tsc

Thanks!--didn't know that file existed.

So here's the MSL sol ephemeris recomputed using LMST:

 msl_sundataV2.zip ( 33.04K ) Number of downloads: 784