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How to Ride a Comet

Treacherous Challenges Ahead for Rosetta's Mission Control Team
8/11/2014 01:01 PM EDT
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Max The Magnificent
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flatulent frat boy
Max The Magnificent   8/11/2014 1:58:14 PM
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@Karen: ...the comet, like a flatulent frat boy, might suddenly belch out a flume of gasses...

What can I say -- your words transported me out into space -- it's like I was there LOL

kfield
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Re: flatulent frat boy
kfield   8/11/2014 2:43:25 PM
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@maxmaxfield: What can I say -- your words transported me out into space -- it's like I was there LOL

I'm so pleased that my very prose struck such a chord with you, and I'm sure it was a trip down memory lane to your own, uhm, frat boy antics of the day!

David Ashton
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Re: flatulent frat boy
David Ashton   8/11/2014 6:20:53 PM
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Yep, nice turn of phrase Karen!   Brought to mind an old movie - "King Frat"  the highlight of which was a farting competition...which was won by a girl.  A bit like National Lampoon, but worse..... (You weren't an actress in a past life were you?? :-)

kfield
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Re: flatulent frat boy
kfield   8/11/2014 9:46:28 PM
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@DavidAshton "Yep, nice turn of phrase Karen!   Brought to mind an old movie - "King Frat"  the highlight of which was a farting competition...which was won by a girl.  A bit like National Lampoon, but worse..... (You weren't an actress in a past life were you?? :-)"

A girl won the competition, eh? How unladylike!  I was an aspiring actress in like second grade or so, but I couldn't stop giggling uncontrollably when I read my lines, so they put me to work behind stage. :-)

Max The Magnificent
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Re: flatulent frat boy
Max The Magnificent   8/12/2014 10:08:47 AM
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@kfield: ...so they put me to work behind stage...

I've been told that I have the face to be a radio anouncer (wait a minute... :-)

kfield
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Re: flatulent frat boy
kfield   8/14/2014 3:44:57 PM
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@maxmaxfield "I've been told that I have the face to be a radio anouncer (wait a minute... :-)"

I may have suggested that to you once in the past, but I was only joking. :-)

Max The Magnificent
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Re: flatulent frat boy
Max The Magnificent   8/12/2014 10:07:11 AM
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@David: You weren't an actress in a past life were you?

Oooh -- just you wait till she get's her hands on you at EE Live 2015

David Ashton
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Re: flatulent frat boy
David Ashton   8/12/2014 6:26:20 PM
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@Max.... I didn't tell you I was into BDSM, did I?? :-)

Max The Magnificent
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My memory isn't what it used to be...
Max The Magnificent   8/11/2014 2:00:50 PM
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@Karen: ...though the 10-year-old Rosetta was designed in the 1990s and only has 2 MB of RAM, of which only half can be accessed by the operating system due to CPU budget constraints...

So if they'd had a larger budget, the operating system would have been allowed to access the other half of the RAM?


It really makes you realize what you can do with very little if very little is all you've got...

 

David Ashton
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Re: My memory isn't what it used to be...
David Ashton   8/11/2014 6:22:04 PM
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@Max....one wonders why they did not leave the other 1MB out to save weight & power??

kfield
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Re: My memory isn't what it used to be...
kfield   8/14/2014 3:43:47 PM
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@maxmaxfield :So if they'd had a larger budget, the operating system would have been allowed to access the other half of the RAM?"

I emailed Andrea Accomazzo of ESA to shed some light on your question and here is his answer:

"Yes, we could use part of the RAM extension but the CPU budget would decrease i.e. we would have the risk that the computer would not be able to run all the actions it has to run within the allocated time i.e. activities on-board would start being delayed which would be catastrophic for the mission. 

Proper timing of orbital and attitude manoeuvres is essential for mission success. If the spacecraft can not execute them then we could not manoeuvre properly around the comet. 

In reality the on-board computer has a protection against over-run but it would re-boot thus entering a safe status where all programmed activities would be de-scheduled i.e. the mission would be temporarily interrupted with an obvious disruption of science production and delays."

Max The Magnificent
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Re: My memory isn't what it used to be...
Max The Magnificent   8/14/2014 3:45:56 PM
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@kfield: I emailed Andrea Accomazzo of ESA to shed some light on your question and here is his answer...

Ah ha -- I thought you meant a financial budget, not a CPU-cycle budget ... now all becomes clear -- thanks for following up on this

eetcowie
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comet entrails
eetcowie   8/12/2014 1:29:52 PM
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the comet has a heavenly body...

David Ashton
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Re: comet entrails
David Ashton   8/12/2014 6:28:03 PM
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@EETCowie....Ivan, the caption competition is on another page (but I see you've been busy there as well :-)

DrQuine
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CEO
In orbit around a small comet
DrQuine   8/17/2014 5:50:48 PM
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The fact that Rosetta has traveled billions of miles to find and orbit a comet that is only 2.5 miles by 2.2 miles is extraordinary. As I understand, escape velocity from the comet is about 1 mph so if we walked on the surface, we'd "launch" off the surface, leave the comet's gravitational field, and be floating in space. It is hard to imagine the fine adjustments that must be made by Rosetta to remain in the vicinity.

ScRamjet
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Too Bad
ScRamjet   8/19/2014 8:30:38 AM
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 They can't beam a modern CPU / Ram set to Rosetta. Technology has inproved by orders of magnitude in 10 years.

Now for the same weight and less power, they could be using an onboard Computation to have Rosetta calculate it's own corrections.

This would require a rangefinder (pulse LASER?) and very sensitive accelerometers to determine proximity / orbit deflection and then adjust accordingly.

I notice they don't mention the onboard fuel for corrections, this is also limited, but hopefully they have plenty for now.

All in all, a very interesting problem.

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