PART 1: Send in your questions to be answered by the Galileo team
PART 2: Sticking a radio in an oven for science
PART 3: Scientists do have a life away from work
PART 4: Planning ahead and catching up
PART 5: Working on software and ordering flowers
PART 6: Subscribing/Unsubscribing: How to do it

Just a reminder that the OFJ97 project is now accepting your questions to be answered by the Galileo experts. Questions will be accepted until April 6th. We've got experts lined up from different parts of the project to answer all of your Galileo-related questions. To see the questions and answers from the original OFJ project, check out:

http://quest.arc.nasa.gov/galileo/Galileo-QA

Questions can be submitted to question-jup@quest.arc.nasa.gov but please send only one question per message.

For further information and instructions on sending us your questions, please visit:

http://quest.arc.nasa.gov/galileo/ask-questions.html

[Editor's Note: Dave was in charge of the Doppler Wind Experiment on the probe.]

It's hard to believe that more than a year has passed since we arrived at Jupiter. At 3:15 P.M. on Saturday, December 7 I thought back over the excitement of one year ago, and the activities that have followed. After receiving the wind experiment data in bits and pieces following the arrival of the probe at Jupiter, the wind analysis was completed between press conferences, professional conferences, and writing papers. There was also a lot of travel. Right after the probe mission, I was going to a conference or meeting every month all over the world: San Jose, Houston, The Netherlands, England, to name a few.

For me, however, the best part has been sharing the thrill of going to Jupiter. In the past 15 months I have been to many, many elementary schools, astronomy clubs, high schools and colleges throughout Idaho, Washington, California, and Arizona. Since the whole purpose (and the most exciting part) of science is sharing what is learned, I am hoping to continue visiting schools and groups for a long time.

The culmination (although not the end) of these trips was in early January, more than a year after our arrival at Jupiter. A conference was held in Padova, Italy to celebrate Galileo the scientist, Galileo the spacecraft, and Galileo the Telescope (The Galileo National Telescope, which is being built in Italy). On the last day of "The Three Galileos" Conference, we all visited the Vatican where we had an audience with Pope John Paul II and a tour of the Vatican Observatory.

Throughout the year there have been many occasions where I have had to sit back, catch my breath, and think to myself that we made it to Jupiter! We were *really* there - tasted it, touched it, smelled it, saw it. It is sometimes difficult for me to completely comprehend what was accomplished in December, 1995, and what is still being accomplished now as the orbiter continues to study the planet and its moons.

So, in between being philosophical and sentimental, I have had some work to do. For several reasons it has been difficult to make sense of the wind measurements. First, to determine the speed at which the probe was drifting in the winds, I needed to know the speed at which the probe was falling on its parachute through the atmosphere. This is easy to calculate (sort of) if you know how fast the atmospheric pressures and temperatures are changing. Fortunately, these measurements were made by the Atmospheric Structure Instrument (ASI). Unfortunately, like the rest of the probe, the ASI got much, much hotter than it was supposed to. Imagine putting a radio into your oven and turning it to 300 degrees Farenheit (Kids - don't let your parents try this at home!). Your radio wouldn't last very long!

The inside of the probe is thought to have reached about this temperature (300 degrees) before it stopped working. So before we could completely understand the probe data, including the radio frequency of the probe signal used for the wind measurements as well as the ASI data, we had to go back and see how the instruments worked at very hot temperatures. During the spring, summer, and into the fall we took some spare instruments and put them into ovens at NASA Ames Research Center to see how well they worked as the temperatures got higher. It has only been in the past several months that we finally decided we understood how well the probe instruments were working and felt confident that the wind measurements were correct.

So - what are the winds? It looks like we have had a big surprise - the winds don't get weaker as we go further beneath the cloud tops. They get *stronger*. At the cloud tops the winds are about 100 m/s (this is a breeze of about 220 miles per hour). As we go down the winds start picking up, reaching some nice kite flying weather of about 175 m/s (about 385 miles per hour).

So, is the work finished? No - there is still more to do. When the effect of the wind is subtracted away from the probe signal frequency, we are left with the "left-over" frequency (the frequency residuals). This is due to probe motion caused by something other than the winds. In the frequency residuals I think I can see the effect of the probe spinning, and the swing of the probe under the parachute. There is some turbulence causing the probe to bounce and this is probably in the frequency residuals as well. So I now get to start analyzing the residuals, and, once I am finished, I should know exactly how it would have felt to sit on the probe as it plunged deeper into Jupiter's atmosphere. Every swing, sway, bump, and turn the probe made during its final hour will be discovered.

What now? Of course, Galileo still takes much of my time. I am currently on a research sabbatical from my university in Idaho and spending a warm winter at the Lunar and Planetary Laboratory in Tucson, Arizona. My work now is concentrating more and more on the next great exploration - the Cassini mission to Saturn and its largest moon Titan. I am once again involved in measuring winds, this time on Titan. My guess is that the exploration of Titan and the discovery of what lies beneath its atmospheric haze - mountains and glaciers? Seas and lakes? - will be one of the most exciting chapters in the history of solar system exploration. Mark your calendars - we leave for Saturn next October (1997) and arrive in July, 2004.

[Editor's Note: Laura Barnard is an Engineering Aide for the Science Planning and Operations Team.]

This last weekend I worked at spring cleaning my house. My husband is sick with this nasty flu that is going around, and I wanted to do something. We have a large garden as well, so I did weeding and dormant care of my roses and fruit trees. My apple trees are already in bloom. They are very beautiful despite being only two year old twigs. My neighbors are gone for the week enjoying Mardi Gras in New Orleans, so I put their garbage and recyclables out for them as well as our own. Weekends are usually spent doing chores, unfortunately. My house is in good condition, so there isn't heavy maintained to do, however like I said there is a large yard that requires care. I love gardening anyway, so it is not such an arduous chore. Sometimes we'll go see a movie or go out to lunch, but the majority of my weekend is spent outside in the garden, cooking, and reading while we listen to the radio. Exciting huh?! Relaxing I say.

Monday, it was back to work, starting with web page maintenance. I usually look at all of the sequences that we are putting together or getting data for, and put all of the important deadlines on one page that is kept as current as possible. I still didn't have the navigation trajectories from last week's project science meeting so I sent email to the navigation team asking for their presentations. They were sent in less than an hour, so I put them on once I was done converting them to portable document format (PDF). This format allows anyone on the web, despite different platforms to read the document if they have the free Adobe Reader.

After I finished the web information I worked on the sequence G7 (Ganymede - 7th orbit). I loaded the pieces of the sequence that we have done into MIRAGE (Mission Integration, Real-time Analysis and Graphical Editor Software) [Please note - this software is so common to me that I will refer to it as MIRAGE from now on]. I then executed models so that the software would look at the instrument and spacecraft resources. As I was doing this one of the team members came in and asked user questions about MIRAGE. I went to his office to see exactly what he was doing, and I found that he had problems with his files, and the resource file that he was using. Once I determined that (after an hour!) it was fairly easy to fix the sequence so that didn't crash the software. When I returned to my own work I found a bug in the software that made my reports inaccurate. I told the programmer, and notified the team of the bug. It was a simple bug that only took our programmer a couple of hours to fix.

For lunch another team member came to my desk with a personal request. Sometimes I can be bribed! I actually needed a product from this person that was late, so I told him that I would do it only if I got my product! It worked. I got my sequence product and he got his color graphics! After lunch I continued to work on the G7 sequence and testing the new MIRAGE that had the bug fixed.

[Editor's Note: Laura Barnard is an Engineering Aide for the Science Planning and Operations Team.]

This morning our team chief wanted to double check the Europa 6 (E6) sequence before it is sent to the spacecraft later tonight. The problem is the tape recorder. It has four "tracks" (the tapes that you are used to have two tracks: one going forward, one going backward. Galileo's tape recorder has two going forward, and two backward). Whenever the tape is switching direction, it can't record any data. Our software lets us check when the tape will turn around. Usually we tend to trust our models, but with the differences between the command software and our planning software we get concerned about WHEN the tape will change to the next track. If the tape turns too early or too late we will lose our timed observations that we are recording during the encounter. Europa has so much good stuff that we don't want to lose anything if we can help it! So once again I loaded up the current sequence and ran it through our planning software MIRAGE. Do you see a trend here? Everyday I am working with my computer and different pieces of software modeling different things. Small wonder I don't use my computer at home!

With the completion of one sequence (E6, the one that's currently running on the spacecraft), it means that we need to start working on the next. We are constantly rolling off one sequence and starting another. In actual fact the entire science team is actually working on four plus sequences at any one time (or more if you are behind schedule!). For instance: Right now, the spacecraft is in the Europa 6 (E6) sequence. We just finished getting back the data on the tape from the Europa 4 (E4) orbit. We also have plans in place for Ganymede 7 (G7) that are now going to the sequence team for iteration and final checks. The science teams are also working on the Ganymede 8 (G8) sequence. Whew! If you are someone like me that also does archiving for the team as well, you are working on so many sequences that you have to ask what sequence they want to look at!

For the rest of the afternoon I looked at the predictions of the tape movement for the next (G7) sequence. I found some disturbing things that will have to fixed. Near the beginning of the G7 sequence, the tape is supposed to slew (kind of a fast forward). However, my model shows that it will stick (which was exactly what caused our big problems with the tape recorder before), so we have to make sure we make that slew earlier. There isn't much time to make that change, so everyone has to hurry a little to make sure that the commands get rearranged properly.

[Editor's Note: Tal Brady designs and programs the flight software for the Control and Data Subsystem (CDS) computer.]

The imaging team sent the results of their tests of the new Solid State Imaging (SSI) camera software for Phase-3. This is the software that runs the camera if the tape recorder breaks down, forcing us to use the contingency flight software. SSI has worked out a way to run their software under Phase-3 conditions (and in the latest delivery, the 2 pixel by 2 pixel summation mode of imaging can now be read from the camera one line at a time). Unfortunately, our Phase-3 CDS flight software, which is due for delivery on Monday (2-17), will need changes in order to work correctly with the new SSI flight software. Looks like the next three days will be busy, but at least this should be the last big change needed for the Phase-3 software.

2-14-97
Valentine's Day -- ordered flowers for Mom over the web. The picture looked nice. She called and said she really liked them, so that worked.

Looked at the Operations schedule, which lists what's going on with the spacecraft. Playback of the taped data from the E4 orbit ends this weekend and the E6 encounter starts. Wow, seems like things are moving fast.

Delivery of Phase-3A flight software is still scheduled for Monday (2-17) afternoon. Still working on problem fixes for the imaging support. Looks like some weekend work will be needed to check out some of the new software being written today. We could use some more time to test it, but we need to do the post delivery system tests (which will look at *all* of the software running together--the flight software, the instrument software, and so forth) as early as possible to see if we can get images from the camera correctly.

2-17-97
E6 encounter has started. Everything seems to be working well. It looks like we start with some Jupiter and some Io science before we do Europa closest approach Thursday (2-20).

Delivered the new Phase-3A flight software this afternoon. The test team will start running the post delivery system tests tomorrow. The software still needs more testing by the development team then it's getting. More problems are likely to show up in the systems test, which is time consuming and annoying. Fortunately, all of the Phase-3 software except the new imaging software is stable and tested. Of course we all hope we never have to use the Phase-3 software, and as long as the tape recorder continues to work well we won't. It's a good idea though to have backup software, just in case. Developing this Phase-3 backup software took months, and each orbit is about a month. We wouldn't want to lose 4 or 5 orbits of data developing the software after a recorder failure, if one does happen.