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Mariner 9 -- still in orbit?
Doug M.
post Mar 15 2015, 06:44 PM
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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 wikipedia page gives a date of 2022, 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.
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Habukaz
post Mar 15 2015, 08:43 PM
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Retrieved a working link of the Wikipedia reference via the Wayback Machine:

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

QUOTE
Mariner 9 remains in orbit around Mars until 2022, when it is expected to burn up or crash on to the surface.


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mcaplinger
post Mar 15 2015, 08:45 PM
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QUOTE (Doug M. @ Mar 15 2015, 11:44 AM) *
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?

http://starbrite.jpl.nasa.gov/pds/viewMiss..._NAME=MARINER71

QUOTE
On October 27, 1972, telemetry data indicated that the spacecraft was no longer capable of holding the fixed attitude and, as the last battery power was being used, a final command was sent to stop transmitting. The slowly tumbling Mariner 9 will remain in orbit for a minimum of 50 years before it enters the atmosphere of Mars, disintegrates, and falls to the surface.


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."


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Disclaimer: This post is based on public information only. Any opinions are my own.
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djellison
post Mar 15 2015, 08:46 PM
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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.
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nprev
post Mar 16 2015, 12:23 PM
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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.


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vikingmars
post Mar 16 2015, 02:27 PM
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QUOTE (Habukaz @ Mar 15 2015, 09:43 PM) *
Retrieved a working link of the Wikipedia reference via the Wayback Machine:

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 wink.gif
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mcaplinger
post Mar 16 2015, 02:52 PM
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QUOTE (nprev @ Mar 16 2015, 05:23 AM) *
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...

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.


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JohnVV
post Mar 26 2015, 11:21 PM
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the naif kernel from 1999 has the 71 & 72 dates
CODE
BRIEF -- Version 4.0.0, September 8, 2010 -- Toolkit Version N0065

Summary for: m9.bsp

Body: -9 w.r.t. MARS BARYCENTER (4)
      Start of Interval (ET)              End of Interval (ET)
      -----------------------------       -----------------------------
      1971 NOV 14 01:30:00.000            1972 MAR 29 21:00:00.000
      1972 APR 01 20:00:00.000            1972 APR 14 06:30:00.000

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