[X] My Assistant

[Bill Harris]

will be some form of active EM shielding, essentially a mini-magnetosphere

"Aye, Cap'tn Kirk, I canna make the shields hol out much longa..."

Sorry, I couldn't help this one.

I've heard of that as a magnetic field around a superconducting coil.

--Bill

[Guest_BruceMoomaw_*]

Galileo had no reaction wheels -- but its "dual-spin" design, which was supposed to be simple, ended up giving them cat-fits during the initial design period, and JPL has since sworn "never again". (They had particular trouble transferring electrical signals properly between the two sections of the craft, largely due to tiny bits of debris getting into the electrical brushes -- and indeed that problem caused resets periodically during the flight itself.)

[tasp]

I wonder how we are ever going to have probes explore the inner Galilean moons without their being fried by the radiation and not have to bring a ridiculously heavy amount of shielding with them?

Having a Galileo II craft travel in an inclined path around Jupiter would help. The radiation seems to increase in the equatorial plane.

Having a probe cross the equatorial plane in the 'radiation shadow' {of a major moon} would help too.

{IIRC, the shadow won't necessarily be where you think it is }


Edit: clarified where to find radiation shadows, sorry for omission.

[The Messenger]

Galileo had no reaction wheels -- but its "dual-spin" design, which was supposed to be simple, ended up giving them cat-fits during the initial design period, and JPL has since sworn "never again".  (They had particular trouble transferring electrical signals properly between the two sections of the craft, largely due to tiny bits of debris getting into the electrical brushes -- and indeed that problem caused resets periodically during the flight itself.)

Thanks, Bruce, this is a question I have been trying to get a reasonable answer to, for a very long time: Dirty brushes I can understand, cosmic rays that lurk near moons? - I don't think so.

[Guest_Sedna_*]

By the way, there are both talk and poster sessions of Genesis mission results planned for the 2005 Fall Meeting of the American Geophysical Union in San Francisco.

--Emily

Good to hear, we'll have then the chance to discuss and learn with that folks

[hendric]

Or Genesis. I seem to remember reading somewhere that the gravity sensor that would have told the parachute to deploy was put in upside down.

It wasn't that simple... You couldn't tell externally which way was down. You had to X-ray the sensor! Like, hadn't these guys heard the story of the Claymore mine? "THIS SIDE TO ENEMY"! They had two pairs of two sensors, I don't understand why they didn't have one of each pair flipped WRT the other, then this wouldn't even have been an issue. They did say Stardust won't have this issue, maybe that's what they did?

[hendric]

So,, any bets on the next time we'll see a deployable HGA on a probe? I think the Galileo idea was a good one, it just got screwed by Challenger. Looking at the amount of data we're getting back from Cassini, I'm both saddened and awed at what Galileo accomplished.

[djellison]

Well the TDRS sat's launch with deployable HGA's - but I'm not sure if their design would be applicable for deep space applications instead of GEO.

Doug

[Guest_BruceMoomaw_*]

Galileo's antenna WAS an exact copy of the TDRS ones, which is why everyone was so confident that it would work. No one ever dreamed of truck vibrations as a cause of trouble.

At the COMPLEX meeting the suggestion was made that Europa Orbiter could easily increase its bit rate with an unfolding antenna. Universal groans followed; "Been there, done that," somebody muttered. I think this is unfair -- you just have to design the damn thing with more excess unfolding power.

[The Messenger]

Good to hear, we'll have then the chance to discuss and learn with that folks

It is good to hear that most of the samples are/have been recovered. So what is the sun made out of, besides that light stuff we can see?

The Utah- Nevada Desert that Genesis crashed in, is a remarkable area for artifacts. Here is a great story:

A few years ago, my (former) wife was running a desert field survey near the Utah/Nevada boarder with a crew of archeological techs, and came across a crashed UFO.

No, really, an honest to God, saucer-like vessal about the size of a motor boat that had pancaked and broken into the sand. They were about a mile away (and spread out, because they were surveying), but she was closest, and her crew kept asking over the headphones what in the hell it was, and looking through the bonoculars the only thing that she could say is that 'It looks like nothing other than a crashed UFO'.

She promised the crew they would go back and check it out, after lunch, but that proved unnecessary: One of the marques on a local hotel said "Welcome: Crew of Independence Day." Nice prop. By the time they returned, the 'ship' had disappeared and returned to Hollywood...or hidden in Area 51, if you are into that kind of thing.

[mike]

Thank goodness for movies like 'Independence Day'.. There just aren't enough stories about aliens blowing up the planet.

[ljk4-1]

Galileo's antenna WAS an exact copy of the TDRS ones, which is why everyone was so confident that it would work.  No one ever dreamed of truck vibrations as a cause of trouble.

At the COMPLEX meeting the suggestion was made that Europa Orbiter could easily increase its bit rate with an unfolding antenna.  Universal groans followed; "Been there, done that," somebody muttered.  I think this is unfair -- you just have to design the damn thing with more excess unfolding power.

How about an inflatable antenna?

How goes it on the plans for an interplanetary communications network?

[ljk4-1]

It is good to hear that most of the samples are/have been recovered. So what is the sun made out of, besides that light stuff we can see?

The Utah- Nevada Desert that Genesis crashed in, is a remarkable area for artifacts. Here is a great story:

A few years ago, my (former) wife was running a desert field survey near the Utah/Nevada boarder with a crew of archeological techs, and came across a crashed UFO.

No, really, an honest to God, saucer-like vessal about the size of a motor boat  that had pancaked and broken into the sand. They were about a mile away (and spread out, because they were surveying), but she was closest, and her crew kept asking over the headphones what in the hell it was, and looking through the bonoculars the only thing that she could say is that 'It looks like nothing other than a crashed UFO'.

She promised the crew they would go back and check it out, after lunch, but that proved unnecessary: One of the marques on a local hotel said "Welcome: Crew of Independence Day." Nice prop. By the time they returned, the 'ship' had disappeared and returned to Hollywood...or hidden in Area 51, if you are into that kind of thing.

Some of the reasons given for the infamous Roswell saucer stories included the air drop tests of the Voyager and Viking Mars probe heat shields in the 1960s and 1970s, which looked an awful lot like a typical saucer-shaped UFO.

See the images at the end of this page:

http://www.af.mil/library/roswell/

The Roswell Air Force Base has one of the actual Voyager heat shields on display, or at least they did when I saw it in 1995.

[The Messenger]

How about an inflatable antenna?

We have experimented a lot with using low density foams to build space structures, and they work very well in low pressure, low G environments. This would be another good use for the ISS, experimenting with large-scale expanding Tinker Toys.

[Bob Shaw]

The Roswell Air Force Base has one of the actual Voyager heat shields on display, or at least they did when I saw it in 1995.

Now that's a helluva link - I didn't know *any* Voyager hardware was built, let alone flown (that's the *original* Voyager, chaps - the twin-payload Saturn V Mars mission!).

Bob Shaw