Rev 49 - Aug 9-Sep 14, 2007 - Iapetus I1, The only close flyby of Iapetus Options

[Bjorn Jonsson]

On one hand, it's a bummer. On the other hand, it gives us another chunk of "Here there be tygers" terrain in the solar system to look forward to discovering in the futue.

I get the impression that poorly imaged terrain isn't going to be any bigger than would have been the case had nothing gone wrong. Seems to be global multispectral coverage that was lost.

[belleraphon1]

"Some see the glass as half full,
some see the glass half empty,
and some see it as time for another round."
-Mike

Remember Voyager 2? We lost all the high res on Tethys and Enceladus when the scan platform seized up.
Plus all the post close encounter flyby science except for a long distance Phoebe image. Amend that, we did get particles and fields data.

The glass is definitely more than half full, and this just means we go for another round (extended mission).

Craig

[scalbers]

??? We will fill that gap, don't worry! Just not tonight...

It certainly has not been a disaster. Aggravating, but not a disaster. We will get nearly all the high-resolution science we planned on.

By the way, the REGMAPTRL001 images are just fine! Most of that just won't get played back until tomorrow.

That sounds very encouraging - thanks for the report. We would then see the global mosaic of the receding lit side. It will just be slightly more challenging to map without the best quality global context view (except we might later get something from roughly 700000km distance). There'll be plenty of time though for that!

[JRehling]

[...]

[Ian R]

Ian - what? Solid state power switch trips occur several times a year, each time safing the s/c. We don't always hear about them, they're mostly mentioned in Cassini weekly reports.

Gordan - I was referring to the article on the Cassini website that stated: "The last time Cassini was in safe mode was over four years ago."

[OWW]

I thought REGMAPTRL001 was after the fateful downlink? Shouldn't it be lost?

[Roby72]

??? We will fill that gap, don't worry! Just not tonight...

It certainly has not been a disaster. Aggravating, but not a disaster. We will get nearly all the high-resolution science we planned on.

By the way, the REGMAPTRL001 images are just fine! Most of that just won't get played back until tomorrow.

A few CIRS global maps should also be gone. And outbound RADAR data...

BTW, I m happy that the REGMAPTRL001 sequence is ok

Robert

[monitorlizard]

I don't think we can count on another Iapetus flyby to be added to the extended mission. After all, they worked on designing the extended tour for a couple of years, so it's pretty much set in stone. But there is predicted to be approx. 125 m/sec delta-V left for Cassini at the end of the extended mission, making an extended extended mission possible. Another Iapetus flyby should get some consideration for that, though I would have wished for a reason other than data loss in this flyby.

Fortunately, an extended extended Cassini mission fits in perfectly with Alan Stern's "squeeze every drop of science out of every spacecraft" philosophy.

[Rob Pinnegar]

It'd be nice to see another flyby, but with the science objectives from this one having apparently been fulfilled, that just doesn't seem too likely. Yeah, it'd be nice to see the Moat in sunlight, but that's probably not worth the trouble of setting up another flyby in three or four years' time.

On the lighter side, I just checked out the Front Page list of all the members currently browsing Unmanned Spacecraft. About 25 right now, almost all of whom are fairly obviously here for the Iapetus flyby.

[volcanopele]

I thought REGMAPTRL001 was after the fateful downlink? Shouldn't it be lost?

The REGMAPTRL001 sequence occurred on September 10 at 22:40 UTC and ran through September 11 at 00:40 UTC. The first downlink started on September 11 at 05:30 UTC. We got most of the first frame and expect the rest during tomorrow's downlink.

[OWW]

I keep staring and staring at the timeline:

http://planetary.org/news/2007/0906_Cassin...ns_YinYang.html

But I don't see any REGMAPTRL001 before the +6h mark. I really can't see how REGMAPTRL001 could have survived. Am I missing something?

EDIT: thanks VP.

[OWW]

From Emily's blog:

If you read my timeline, the safing event happened right about 6 hours after closest approach, after all the highest-res observations. Nothing after the 20:05 mark of the timeline was executed, which is too bad, but all the good stuff is there.

Maybe a small error? Should it read 14 hours and 05:10? That would be a small relief.

[Rob Pinnegar]

Umm. So if I'm correctly reading the information from Jason, and from the mission timeline:

(1) There was a very brief downlink 6 hours after C/A.

(2) A much longer downlink had been planned for 15 hours after C/A. However, a cosmic ray hit occurred just after this downlink started, delaying its completion by a couple of days, but not leading to any loss of data.

There seems to be some confusion regarding which of (1) and (2) constitutes the "first post-flyby data downlink". Number (2) would have been the first MAJOR post-flyby data downlink.

Maybe the fact that the cosmic ray hit happened to occur around 6:00 UTC contributed to this?

[Phil Stooke]

Here's another of the saturnshine images - a composite of three frames. Not very pretty...

Phil

[elakdawalla]

You're quite right, Rob, my error I've now fixed my blog entry.

Very, very sorry to have scared you all, folks.

Can't imagine why the data hasn't hit the raw page yet. I now won't be able to work on these pictures anymore until the baby goes to bed. It may be an early bedtime tonight...

--Emily