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Posted by: Doug M. Mar 15 2015, 06:44 PM

I've read in various places that Mariner 9 was supposed to remain in orbit until sometime in the 2020s or 2030s. However, I've never seen an authoritative quote for the exact end of its mission. (One may not exist, of course.) The http://en.wikipedia.org/wiki/Mariner_9#Present_location, with a footnote, but unfortunately the link (to a NASA page) is dead.

Does anyone know anything more? Also, would it be theoretically possible to image Mariner 9 (assuming we knew where it was) using any of the other orbiters?


Doug M.

Posted by: Habukaz Mar 15 2015, 08:43 PM

Retrieved a working link of the Wikipedia reference via the http://web.archive.org/web/20130514043808/http://www.nasa.gov/offices/oce/appel/ask-academy/issues/volume4/ata_4-9_mariner_9_prt.htm:

http://appel.nasa.gov/2011/11/27/ata_4-9_mariner_9-html/

Posted by: mcaplinger Mar 15 2015, 08:45 PM

http://starbrite.jpl.nasa.gov/pds/viewMissionProfile.jsp?MISSION_NAME=MARINER71



Since we don't have good tracking data from the end of mission and even if we did there are enough random factors in orbit lifetime, any prediction would be meaningless.

Since we don't know where it is, it's not really interesting to think about imaging it, though I'm sure it's "theoretically possible."

Posted by: djellison Mar 15 2015, 08:46 PM

Theoretically possible to image it? Yes. MGS imaged MODY and MEX. I'm sure MRO could manage a similar stunt.

But we don't know where it is - so it's out of the question.

Posted by: nprev Mar 16 2015, 12:23 PM

I'd actually be surprised if it is still in orbit. That 50-yr minimum estimate was made a long time before the dynamics of the martian atmosphere were well understood to say nothing of the detailed behavior of its upper portion. Plus it was, what, four solar cycles ago or so?

Tons of variables, but most of those would seem to act to decrease orbital longevity rather than prolong it. We'll never know, unfortunately.

Posted by: vikingmars Mar 16 2015, 02:27 PM

Dear Habukaz, thanks a lot for the link.
However, unlike that is said in the caption of this webpage ("Image of landslides in the Melas Chasma on Mars taken by Mariner 9. November 13, 1971 .../... "), the image inserted was not taken by Mariner 9, but by Mars Odyssey

Posted by: mcaplinger Mar 16 2015, 02:52 PM

On the other hand periapsis was about 1600 km so it's not like it gets deep into the atmosphere.

There might be some insight in http://adsabs.harvard.edu/full/1974CeMec...9..395B but I haven't read it yet.

Posted by: JohnVV Mar 26 2015, 11:21 PM

the naif kernel from 1999 has the 71 & 72 dates