I also think that MGS was a fine spacecraft and wish it was around for another Martian year or two. But I was wondering: in what way will our presence at Mars be different without MGS? Are there some capabilities which are not overlapping with MRO and Odyssey?

Well - if you take MARCI, HiRISE, CRISM and MCS on MRO, you have basically covered or exceeded all of MGS's abilities with MOC2 NA, MOC2 WA and TES. MOLA was working passively having had a failure of the circuitry that 'pinged' the laser. We've also lost the MAG, but I don't know what, if any capacity to get similar data SHARAD and MARSIS have.

What we have really lost is repeatability and overlap. One of the key things that the most recent extension was being talked about as usefull for was revisiting site previously imaged by MOC to identify changes. Technically possible with HiRISE, but there is something to be said for doing repeat obs with the same instrument at the same local time. Also - one could do a 'scout' observation with MOC before turning on HiRISE to grab an image. Also - it would have been usefull to have MOC WA global coverage to overlap with the MARCI coverage as a 'transition' phase, and also to offer two daily sets of observations a couple of hours apart to identify motion etc.

Doug

If MGS is OOC, we've lost a high quality, reliable and proven instrument able to image surface features at 1.5m resolution. It's an incredibly valuable asset. Amateurs like us have lost the most as the public targeting program, an effort many of us have participated in, would be at an end. There's still a lot unseen on Mars and MOC is in a perfect position to turn up interesting features that would be missed altogether by HiRISE. It's a tangible loss, but with a sell-by date that has long since passed, we got out moneys worth.

Let's put down the shovels until the doctor signs the death certificate.

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