PART 1: Galileo fact of the day
PART 2: Status of Online from Jupiter: good-bye for now
PART 3: Miles per gallon clarification
PART 4: The Final Push: On to Jupiter! (Part II)
PART 5: An engineer turns media star

Batteries only get you so far in outer space. The Galileo orbiter
carries two radioisotope thermoelectric generators (RTGs), which
are used to generate electrical power on board the spacecraft. There
are 7.8 kilograms (17.2 pounds) of Plutonium-238 in each RTG.

For now, this will be the last regular message of Online from 
Jupiter. We will continue to email a status report about the progress 
of the Galileo mission and science results. You can expect this 
message about once every six weeks. Also, as the Analyze Probe Data 
activity becomes available, it will be distributed here and on the 
Web. Finally, if we are able to bring you another round of Field 
Journals later in the mission when a rich variety of science data 
streams in, such an announcement will first be made on the 
updates-jup maillist. So please stay tuned.

We have received a large number of project evaluations. Thank you 
for your support in this regard. For those that haven't yet chimed in 
with your thoughts, please do. See JUP #28 for a copy of the 
evaluation form; the bottom of this message details how to get to 
the archive of older messages. Or please send email if you cannot 
access this survey form. 

Although we haven't yet thoroughly analyzed all surveys, it is clear 
that the respondents valued the unique perspective that Online from 
Jupiter delivered. It is also clear that folks had many good ideas for 
improvement. We particularly value that input, and will try to use as 
much as possible in the future. By far the most common suggestion 
was to reduce the delay between journal authoring and distribution. 
That is a toughie, but we'll do our best on it. This journal won't
reflect that recent input, as the stories herein are from December.

Throughout, this project has been a lot of fun to develop and deliver.
Thanks for your strong interest and support.

Dr. Jo Pitesky                     Marc Siegel
Galileo Mission Planning Office    NASA K-12 Internet Initiative

In the last message, we reported:
> In its journey from Earth to Jupiter, Galileo traveled 2.4 billion
> miles. Along the way, about 67 gallons of fuel from the propulsion
>system were used. 

Henry Awaya of JPL's Thermal and Propulsion Section responded:

I think it is misleading to infer that the Galileo propulsion system 
fuel has analogy to a car's gas tank. Much of the energy required to 
reach Jupiter had been provided by the launch vehicles. Venus and 
Earth provided additional impetus to allow Galileo to reach Jupiter.
The propulsion system acts more as a navigational, course 
corrective subsystem.

An illustrative analogy would be that the Galileo's propulsion 
subsystem provides a similar function as the steering system in a 
car. The propellant is like the food that the driver ate in order for 
his(her) muscles to turn the steering wheel. If I stretch this 
analogy further, I could say that it only takes the food energy value 
of a candy bar in order for the car to go a couple of hundred 
miles (say 3.5 hours).

So it is important to remember the difference between the course 
corrective system (steering subsystem) and the main drive system 
(engine/gas tank/transmission etc.). 

Thanks to Henry for keeping us honest

[Editor's note: this continues a story started in the previous 
updates-jup message about observing Jupiter from the ground
during Probe entry on December 7]

December 5
By this point, I'm really dragging, but things are OK. The quality of 
the observations is MUCH better, but we're still not quite up to last 
year's level of sensitivity. We got clobbered by clouds a couple of 
times for maybe 1-1/2 to 2 hours today. Also (panic!) one of the 
computers that controls our instrument crashed a couple of times, 
leaving us dead in the water (but since clouds appeared at the same 
time, it wasn't a total loss of observing time).

Bob Joseph, the Infrared Telescope Facility (IRTF) Director, asked us 
for images of Jupiter to show off in Washington. I tell him that 
we're not sure that we can process the data fast enough for him to 
show off by Arrival Day, but we'll try! However, I can send him stuff 
Actually it's dawned on us that the IRTF is THE LAST OBSERVATORY 
to see Jupiter (weather permitting) before Probe entry ... actually 
DURING entry!!!! Our observations are going to give the best possible 
view of the Probe Entry Site!!! This is because the spacecraft's orbit 
insertion burn was scheduled to occur over the Deep Space Network 
(DSN) tracking station in Canberra, Australia. The long-term weather 
forecast is good, but I wish the air were drier so we could avoid 
these awful oddly-timed clouds. Like clockwork, they've appeared at 
1 PM, but they started earlier today and ended earlier, too (aaguh!)

We've agreed to run late, but still allow time to get the PES (Probe 
Entry Site) near the middle of Jupiter's disk. We have to make room 
in time for the day crew to install the next nighttime instrument. I 
want to maintain more than cordial relations with the next observer, 
so I'm going to make sure he has time.

Jose Luis Ortiz, back at JPL, has manipulated the data so that now 
we can see much finer detail. It appears, based on these high-
resolution November data (which the polypropylene will prevent us 
or right on the southern border of, one of the hottest appearing areas 
on the planet - a region most devoid of clouds and probably one of 
the driest places on the planet. I ask Jose Luis, PLEASE, to double-
check the geometric calibration of the image - its "navigation" - so 
we know exactly how certain or uncertain this prediction is going to 
be.

December 6
I head home on a daytime flight, leaving my colleagues to continue 
the effort. It's time to become a Probe Interdisciplinary Scientist.

You can do a lot of traveling when you're doing lots of observing. I've 
accumulated enough United Airlines frequent flyer miles, that they 
reward me every so often with gratuitous upgrades, so I actually fly 
back with a first-class seat (and a first-class meal!). I watch 
cloudless skies and low cumulus from the morning. Like a mother 
hen, I guess, I can't help but make not one but TWO calls to the group 
in the morning from the Honolulu airport where I'm waiting for the 
Los Angeles-bound flight to board.

At home and reading my email, it sounds like the people back in 
Hawaii had a good day of observing and quit "early," giving Bill 
Golisch a break before the next day, arrival day, December 7 - most 
assuredly a very very long day.


Demember 7.
Back at JPL, I need to find the Probe Flight Operations area where 
Probe investigators and Interdisciplinary Scientists will meet to 
watch the day's events unfold. I need to become a father again, too, 
so I drive kids to school.

I decide NOT to gather the images from the telescope while they are 
being collected. While there is a low, low probability of crashing the 
system, I'm getting a little spooked by those systems crashes on my 
last day. Some of the other telescopes start reporting in; 
Pic-du-Midi says they are getting nice images (and since the images 
are on their World Wide Web site, I can see them). They are 
pinpointing the location of the entry site a little further east than 
we are.

I pick up tickets for the family to come on lab to view the Jupiter 
Orbit Insertion (JOI) at a special friends and family viewing site. 
But a call from Linda, my wife, tell me that her knee is hurting (she 
injured it several weeks ago) again, and that she's unlikely to be 
able to bring the kids in.

I grab something to keep from going completely hungry, and head for 
the Probe Flight Operations room. I find that Marcie Smith, the 
Galileo Probe project manager, has not put my name on the list of 
the people authorized to enter (afterward I find out that she thought 
that everyone at JPL would have access!). However, the guard knows 
me, and I guess I have an honest face, so I manage to get in. 

It's close to the time where the Orbiter might signal that it achieved 
a communications lockup with the Probe radio beacon. Being a cool, 
professional scientist, I brought my video camera to document the 
moment. While it's a little embarrassing and touristy, I start to use 
it. (Later someone asks, did anyone take videos?)

A big rush! Probe data signal lockup has been confirmed! It's 
confirmed twice - first at 8 minutes, and then 20 minutes after 
entry, when models predict that the probe is at the 1-bar and at the 
5-bar (5 times Earth atmospheric pressure) levels. So we got a clear 
signal pretty far down into the atmosphere! I call the IRTF in Hawaii 
and let them know that all this work hasn't been for nothing, and 
that's how I showed up on NASA TV. Cake and (technically illegal) 
champagne are broken out, along with little cookies made in the 
shape of the Galileo Probe, courtesy of Probe deputy manager Charlie 
Sobeck (Hey, how did he have the time!!)  :-)

The world gets the news that the probe signal was received! JPL is, 
indeed, a real zoo! The Probe scientists go off to get interviewed by 
the press near JPL's big auditorium, named after Theodore Von 
Kaarman who started rocket testing up here 4 decades ago. I wonder 
what he would think about rocket propulsion near Jupiter today...and 
later on tonight when the JOI burn is supposed to be taking place.

The kids decided that they DID want to see things at JPL, so Linda 
dropped them off. The place is jammed (we're in a not so nearby 
cafeteria in the middle of the JPL campus). There is a little punch 
left but anything solid to eat has long since disappeared. The kids 
instantly are bored. About 30 seconds after we arrive, there is a 
whoop and applause; the main engines have burned successfully and 
the spacecraft is obviously slowing down - something evident from 
the shift in the "pitch" of the radio signal, which is being displayed 
on a graph on the video screen. 

The entertainment continues with the "Not-Ready for Real Time" 
players, a Galileo singing group that creates little self-effacing and 
in-joke songs. I enjoy it and video tape a bit, but the kids are now 
uniformly whining, and everyone else is standing so they can't even 
see the TV monitors even if they could understand what was being 
said...even if they could HEAR what was being said! So we trek off to 
the nearest Burger King (I said not another McDonalds), grab supper, 
and head for home. I catch a bit more news about Galileo (the end of 
the JOI burn went well) before heading back to JPL for several more 
hours to start working on reduction of the data from the IRTF for 
that day. I arrive home at 2 AM.

The telescope support observations are also pretty good news. On the 
island of La Palma in the Canary Island group off the west coast of 
Africa, astronomers at the Swedish Solar Telescope have had a run 
of bad weather, and the Mount Wilson people didn't have much luck. 
But other observatories got good data, and up on Mauna Kea, the IRTF 
folk are reporting nearly perfect weather. 

December 8
I start to take a look at the data used for calibrating our 
observations, but it's no use - I'm dead tired from the preceding 
several days. Galileo's navigators have also helped me avoid a family 
scheduling problem. The closer than expected distance to Jupiter's 
moon Io at closest approach means that if nothing is done, the 
spacecraft will arrive at its next encounter - with the moon 
Ganymede - a week early. It saves propellant, so the Project decides 
that this is a good thing to do. It's also a good thing for me, because 
the original encounter date was for the same date as a conference in 
Paris (which my family had informed me that WE WERE ALL going to 
go to!)...so a fortuitous flyby means that the conflict is removed.

December 9, Saturday
Finally I get to play with the kids, help with housework, and help my 
son distribute his See's candy order to benefit his Cub Scout Pack. 
Still, I check in on everyone at the IRTF, where the observing is still 
going quite well. There'll be a great deal of data to sort through 
before the upcoming press conference.

January 31, 1996 (reporting events from December 7, 1995)
Having given my first interview of the day, I wandered back to Von 
Karman Auditorium. It was now about 9:30 AM. 800 million 
kilometers away, the Galileo Orbiter and Probe were sailing through 
Jupiter's radiation belt, absorbing doses stressful even to its 
heavily shielded electronics. By mid-afternoon, the Probe would 
plunge into Jupiter's clouds, leaving a meteoric streak in its wake. 
Later, it would open a parachute, release its charred heat shield, and 
begin sending atmospheric data to the Orbiter above. After 3 PM, we 
should hear a short message from the Orbiter, telling us the Probe 
data had be received. 
 
That is, if everything worked.

On stage, NASA Administrator Dan Goldin was delivering a pep talk. 
Banks of TV cameras and microphones captured every word. Across 
the Lab, I knew that a far more modest amount of TV equipment was 
set up in Galileo Mission Support Area (our version of Mission 
Control). These cameras watched a handful of engineers looking at 
telemetry from the Galileo Orbiter. They would know before anyone 
else how December seventh, 1995 would be remembered.

I couldn't listen long. A reporter for AP Radio had asked for a 
telephone interview. Unlike the previous one, it was not a live 
broadcast, so it became more of a friendly chat. "What is the mood 
like?" "What's going to happen to the Probe?" Finally, the inevitable 
question -- "What if something goes wrong"? I mumbled vague 
reassurances about how we had great confidence in our equipment.

All this was true, but it certainly wasn't the whole story. For years 
every member of the Galileo team had made the possibility of failure 
an obsession. Any flaw imaginable was considered somewhere in the 
planning -- all so we could be confident today. The catch is, no many 
how many fault cases we talked about, designed against, and tested 
for, the only ones that really mattered would be the ones that 
actually happened today. Would there be one we overlooked? These 
thoughts I left unspoken.

Later that morning, I met a reporter from the Boston Globe. After a 
few minutes conversation, it became clear that interviews are best 
done face-to-face. When asked a question, you can search the 
reporter's face for some sense of what he's really after and know if 
he's gotten it. For example, comparing Galileo's tape recorder 
problems with getting a car stuck in a rut on a snowy road produced 
a look of recognition from the New Englander. Over my shoulder, a 
_Newsweek_ reporter from New York, hearing a new metaphor, began 
to write also.

My next interview was a phone-in to a Toledo, Ohio radio station. My 
few minutes on the air, I learned from the station's producer, would 
be spent chatting with the local DJ between traffic reports. He was 
a computer enthusiast and keen to know the latest from JPL. 
Realizing that afternoon DJs try to be humorous, would I find myself 
struggling for a witty rejoinder? "Oh, yeah!", probably wouldn't do.

Over the telephone, I could hear the radio station report traffic 
conditions and announce a sale at the local hardware store. A few 
minutes later, they spoke of big events in Pasadena and gave a short 
introduction of the Galileo mission. I was on.

It began with friendly banter. What were things like here? Was I 
feeling any tension? These questions were getting familiar, but I 
tried to answer as though I had never considered them before. 
Finally, there was a new one.

"So much has changed since the 1970's and 80's when Galileo was 
designed. Isn't working on Galileo now like taking care of an old 
Buick?"

A moment of panic set in. Handle this wrong, and thousands of Ohio 
commuters would forever picture NASA's prime planetary spacecraft 
as a rusty wreck left unsold in a used car lot.

"Well," I said pleasantly, "there's nothing wrong with old Buicks. 
Sometimes the old things work best. Remember, using the very 
newest equipment available doesn't do much good if the 
manufacturer issues a recall half-way to Jupiter."

"You can't exactly phone the Auto Club from space, can you?", he 
added.

"No, you can't", I chuckled. (WHEW!) 

Around 1 PM, the Probe was only a few hours from entry. Whatever 
would happen to it and the Orbiter was now long past our ability to 
change. We could only watch. The people doing most of the watching 
were locked away in the Mission Support Area, closed off from 
anyone who wasn't required -- including me. While I couldn't 
personally wish that crew good luck, there were plenty of people 
near my old office, all of whom had contributed something to 
programming and operating Galileo, who were available for 
handshakes. Everyone was upbeat.

On my way back at Von Karman Auditorium, I was taken aside for 
another telephone interview. It was BBC Television again, wanting 
more live commentary on today's events. As I spoke, the Probe hit 
the outer layers of Jupiter's atmosphere at over 170,000 kilometers 
per hour. Unfortunately, the distance from Jupiter and the speed of 
light would keep us from knowing the outcome for another 50 
minutes.

Leaving the office, there was one more request, an on-camera 
interview for a local TV station. The interviewer was a different 
sort from the rest. Where others wanted a few facts and a general 
description of "what things are like over there", this fellow was 
interested in my feelings. He wanted to hear my deepest inner 
anxieties and fears. Could I give him my basic human emotions at 
this momentous occasion? "From the gut", was the way he phrased it. 

Well, I thought, there really wasn't any feeling going on inside 
except for a strong desire to go back into the auditorium and check 
up on Galileo. That probably wasn't what he wanted to hear. Better 
answer a different question.

"At this moment, I'm remembering that I've devoted almost one third 
of my life to this one project and I want it all to work."

That seemed to give him what he needed.

Back inside, I was shown to a set of special seats alongside 20 to 30 
members of the Galileo flight team. For some reason, we were all 
grouped together.

The answer became clear as several dozen photographers and TV 
cameramen assembled into a firing line before us. They would 
capture our spontaneous reactions as we anxiously watched the 
minutes tick away. Of course, we were anxious. However, adrenaline 
has many strange and unexpected properties. Now that everything 
possible had been done, we wanted to savor every possible moment 
together. Mostly we laughed and joked and tried to see if there was 
any disappointment on the photographer's faces.

Perhaps sensing that some gesture appropriate, someone near me 
raised both hands to show his crossed fingers. He was answered by a 
volley of camera flashes and TV lights. Some of us shouted 
disapproval at an open display of concern, even a self-mocking one. A 
few discreetly rubbed their hands together in private acts of 
anticipation. Meanwhile, on the TV screens above us, the engineers in 
the Mission Support Area showed they had no time for any of this -- 
they were busy with their work.

Soon, we were told, a message from the Orbiter would tell us that 
Probe data had been collected. The time for that message came -- 
and went. We watched the engineers on the TV screen stare all the 
more intently at the their computer monitors, as though willing 
their displays to change. Like Mission Control in Apollo 13, they 
were wondering if, perhaps, the delayed signal meant there would be 
no signal at all.

As the seconds turned into minutes, I tried to remember all the ways 
Galileo's message could be delayed. I understand how the spacecraft 
works, but the maze of amplifiers and computers that collect and 
process signals from the tracking stations has never been 
completely clear to me. Could some innocuous glitch on the ground be 
causing the delay?

The TV camera lights seemed to grow brighter. Much longer and 
perspiration would bead on our foreheads. This would not be the 
image of calm and self-assurance we hoped for.

Our first sign of hope appeared when the face of one of the televised 
engineers broke out in a broad smile. Around her, people began to 
cheer and shake hands. While we could see her lips move to give an 
announcement, we could not hear her. The entire auditorium had 
erupted in shouts of joy and relief. All around, in a scene repeated in 
dozens of conference rooms and offices, the people of JPL, NASA - 
Ames, and Hughes Electronics saluted each other with cheers, 
handshakes, and "high-fives". Remembering the years of hard work 
and frequent disappointment, a few were even moved to tears.

The Probe had survived and a record of its journey was safely stored 
in the Orbiter. There was still much to do before the Probe data 
would be in the scientists hands, but the most difficult steps were 
behind us.

It was in this euphoric state that I was approached, one final time, 
for an interview. A cable TV reporter asked me to say a few words 
for her and her cameraman. She was articulate and consummately 
professional. Also, she was quite attractive. :-)

The auditorium was still crowded and we must, she explained, stand 
close together for a good picture. Overcoming my shyness, I 
described for her and her cameraman all the pleasure and 
satisfaction the Galileo team felt at this historic moment. It 
seemed to go well, but the cameraman said that the sound wasn't 
very clear. Adjusting his microphone, he asked us to repeat the 
question and answer one more time. Also, could we stand just a 
little bit closer together?

Once more, she asked what it was like here in the auditorium just a 
few minutes earlier. I raised my enthusiasm up one notch and 
answered with the fervor of a sports reporter describing the final 
seconds of a close game. She seemed happy, but the cameraman 
looked back at us sheepishly. He had hit the wrong switch and missed 
some of my comments. Could we do it once again? And this time, 
could we stand side-by-side? 

By now, I could hardly have been more ready. Her questions were 
answered with passion and conviction. Today's accomplishments 
were not merely great, but heroic. If my responses seemed a bit 
lavish, it was because I wanted everyone to know just what it meant 
to the Galileo team that we successfully completed the most 
important, most complex, and riskiest part of the mission. In spite 
of great obstacles, we made it work. When the interview ended, it 
took several minutes for my emotions to carry me gently back to the 
ground.

Meanwhile, on the other side of the solar system, the Galileo Orbiter 
had collected the last of the Probe data and was preparing for 
orbital insertion. The radiation was still intense and might yet 
affect its electronics. If the rocket engine didn't work, Galileo 
would fly on past Jupiter, unable to explore it further. If something 
went catastrophically wrong, there might be no further contact with 
Galileo ever, its precious cargo of scientific data lost.

It was time to start waiting again.

If this is your first message from the updates-jup list, welcome!

To catch up on back issues, please visit the following Internet URL:
http://quest.arc.nasa.gov/galileo/journals/index.html

Note:  As this project has officially ended, these and other inactive mailing lists have been shut down