Agreed, we need those dish arrays for the DSN. But I'm wondering: would having the arrays actually help with this particular problem? I don't know much about radio -- wouldn't it still be a problem to have two transmitters on the same frequency in the same place in the sky broadcasting at the same time, even if you were trying to tune in with two different dishes?

--Emily

Hmm. Well, they wouldn't be exactly the same...there will be minor freq differences & other carrier offsets...so it should be possible to filter out the one you don't want to hear, plus any mutual harmonics. However, we are talking about really low received signal strength, so this might be harder to do than it sounds.

Oh - same freq, same patch of sky - that's always going to be a nightmare situation that no ammount of ground equip will fix - but I seem to remember the MGS issue causing some lost Cassini downlinks - if you had a big array, you could say "right, half to track MGS, and the half for Cassini" - you drop the data rate a bit, but some is better than none - it gives you options.

Doug

Should I resurrect my world-famous (though previously invented in the 1930s) idea about putting TDRS-style DSN relay sats at the Earth/Sun L4 & L5 points?

At the rate they're running out of spares, they'll end up recycling a Marconi spark-gap transmitter on some misison!

Then be sure to teach them how to use Morse code for communication

Not to mention that the NAVCAM CCD was a spare from Cassini!

So in essence, Cassini used a Voyager wide-angle spare camera and replaced the vidicon with a CCD and Stardust took all that and just mounted it on the spacecraft.

You gotta love reusability!

Imagine the kind of spares lying around from military reconnaissance satellites and what the planetary exploration community could do with them. Oh, those selfish, selfish generals!

Cassini also has a new filter wheel to accommodate 18 filters instead of the 8 that Voyager/Galileo/Stardust cameras had. Makes you wonder if the stardust filter wheel, a Voyager spare, got stuck due to age!

Not the same. There is a "production line" for reconsats. Not the same as one time only planetary spacecraft. They would probably use the hardware on the last bird in the series or even put together another vehicle (which had been done before)

that is correct

As I remember it they had a very hard time finding enough hardware left over at the end of the Corona program to cobble together a satellite for display purposes, and that was after 100+ launches. Essentailly all the test and development hardware had been upgraded to flyable status and launched.

http://www.spaceflightnow.com/news/n0708/26mro/

"Alfred McEwen of the University of Arizona, Tucson, principal investigator for the camera, said, "I'm happy to report that there has been no detectable degradation over the past five months." "

"McEwen said, "Given the stability we've seen and understanding the nature of the problem, we now expect HiRISE to return high-quality data for years to come." "

yay!