It seems to be a season of anniversaries over the next year or so.
20 years since Voyager 2 at Neptune (see my posting there), 30 yrs since Voyager 1 at Io,
30 since Voyager 2 at Europa, 30 years since VEJUR at . . . . well never mind!
plus all the Galileo 400th commemorations (I will have more on that next week).

I thought it would be a good time to start a thread on this one, which occurred on a
tuesday morning in July 1979. Although the images had been taken on July 9, they were
recorded for playback the next day. I was a mere summer intern in those days and was attending
the morning briefing along with the rest of the Sci Support Team of which i was a member.
Linda Horn and Ellis Miner were my gurus that wonderful summer. Playback was scheduled for
sometime between 8 and 9, as i recall, and I can still remember looking up at the monitor
as the first high resolution images ever seen of Europa first appeared. Wonderful, even
tho only 2 kilometers in resolution. Little did I know where it would lead me . . .

Here is a restored version of one of the two mosaics returned that day. They hint at some of
the exotic things that Galileo later discovered.

cheers
paul

Those images never get old. I can't imagine what it must have been like to see the surfaces of the Galilean satellites for the first time. Keep the reminiscences coming, Paul.

--Emily

Beautiful! What did you use for color?

I dont remember! so many versions of this and that . . . probably global Galileo color mosaic.

Thank you that is a fantastic image I forgot some of the quality from then.

cool. Alas, this is as close as Voyager ever got. I think it is 1.7 km/pixel, not 2 as i said earlier. It left a lot of people
wondering what was going on inside, but it was more than enough to show Europa was very young indeed
and potentially active (a question still completely unanswered by the way!!). Galileo brought the house down, so to speak.
these are the images i used to show that there was plate tectonics on Europa, an idea that met with a lot of resistance.

paul

Indeed the scientific community had to wait for the "Millennium flyby" of Jupiter to get great images of Europa. Resolution in the Voyagers' images was too poor and no features were named on this icy moon. However, three new feature terms were adopted:

Flexus = cuspate linear features
Linea = straight lines
Macula = circular dark areas



Post Scriptum: shouldn't this be moved to the Pioneer/Voyager subforum
It fits in just fine here.

Actually, that would be Galileo. Not sure what on earth the millennium flyby has to do with it, since Cassini went nowhere near Europa and Galileo's Europa phrase was over.

Several dark bands and three craters got named by Voyager! (and a few other things too). 1.5 km is quite enough to
begin to understand a planet, but not do serious mapping. Voyager was constrained by its trajectory, and it got
500 m resolution on Io, Ganymede, Triton, and Rhea, and 250 meter on Miranda. It pales to Cassini, although Cassini get very little
area coverage at better than 100 meters

Ted, wasn't it about the "Millennium Flyby" that the first detailed maps came out of the Galilean moons. I remember something of not to worry about Io's map as a map made today would be obsolete tomorrow due to the volcanic eruptions.
Well, I guess that the Voyager images were good enough to make the first preliminary pictorial maps of the Galilean moons. However, NASA published a dedicated "Voyager 1 and Voyager 2 Atlas of Saturnian satellites" (NASA SP-474) in 1984 but didn't publish something similar after the 1979 Jupiter encounters?

The USGS published the preliminary Voyager and later updated Gal Sat maps as fold-out maps. they were never hardcopied.
my Atlas of the Gal Sats will be published by Cambridge late this fall. The Saturn satellite updated maps are being handled as on-line products.
paul

Indeed, the only Galilean moon maps I've found are in NASA SP-439 "Voyage to Jupiter" (1980) showing Mercator projections at scale 1:25000000 and Polar stereographic projections at scale 1:13980.
Thank You for the update Paul, and I'm certainly looking forward to Your upcoming book!

happy 30th Europa!!!
july 1979 we got our first good look and have been scratching our heads ever since. I remember that warm sunny july morning long ago when you first appeared on our monitors. true it was a distant view (having drawn the short stick in the Voyager satellite pool), but Galileo got a much better view 2 decades later. Still it doesnt quite match the thrill of that first look 30 years ago today.

Well, I'm officially an Old Dude...brings back so many pleasant memories that seem like just yesterday. 30 years...wow.

Thanks, Paul!

I would have written more but my connection this morning took 1 hour to write one sentence . . .

I was indeed an intern on the Voyager project but not on imaging. rather it was for Ellis Miner on the Science
Support Team, which was responsible for all the planning and execution of the plans. It gave me a healthy respect for those who did not get to appear on camera for the interviews. But also i got to see an encounter as it happened because the images went straight to the JPL TV monitors. Not like Galileo or Cassini which does not quite do that. Jupiter grew larger each day and then on the last day the satellites flashed by quickly. We even had access to quick printers that allowed us to make fast thermal prints. these prints turned black in the sunlight and although i kept some, I have since lost track of those historic photos. I landed in Pasadena a week before the encounter so they immediately put me to work . . . making xeroxes! but i was cool. it was the center of the universe for one week! I relished every minute of it. plus later that summer I was able to make prediction maps for the Saturn moon image due in 1980 and 1981.

paul

Coolness!

I uploaded a new post to my Io blog about this anniversary, and yes, I do talk about Europa with out saying anything derogatory:

http://gishbar.blogspot.com/

Second mosaic taken by Voyager 2. Its in lower resolution (2,23 km/pix) and monochrome, but it has slightly better coverage.

I posted a blog entry with my version of this mosaic.

Here are the two variants of the image, one with the color balance mixed between the actual data and an OGV overlay, the second weighing more heavily on the OGV overlay.

Click to view attachment

Click to view attachment