PART 1: Find Jupiter in the night sky
PART 2: Planning for the "mission" mission
PART 3: Feeding cats and scientists
PART 4: Planning for a big data gathering flyby of Europa
PART 5: Following the journey of particles from Io
PART 6: Subscribing/Unsubscribing: How to do it

Sure, a super high-tech satellite can get you drop-dead closeup views of Jupiter, its moons, and its magnetosphere--but you can see Jupiter itself using just your eyes. If you can also find a pair of binoculars, you may even be able to see Jupiter's distinctive coloring and the four Galilean satellites. We'll tell you when and where to look in the sky to see the largest planet in the solar system, and then we'll have space for you to post your observation reports for comparison with other students around the country. This activity encourages students to find Jupiter in the sky, and describe the process they use as well as the experiences they have if they find it. The experiences, in whatever form, will be posted online for all to see.

Depending on your location, Jupiter will be either difficult or very difficult to find because of its closeness to the sun during the OFJ97 project. However you still should be able to find it, or at least document your experiences!

More information about this activity is online at:

http://quest.arc.nasa.gov/galileo/features/findit.html

[Editor's Note: Ed is with the Mission Planning and Outreach Coordination Office.]

Mission planning on Galileo, now that the spacecraft is deep within its orbital tour, has taken on a different flavor. In part, I am still involved in prime mission activities but this part is more geared toward supporting outreach activities and creating summaries of Galileo's activity during each encounter.

For example, I put together "Today on Galileo" and "This Week on Galileo," summaries of what the spacecraft is doing. These summaries go out all over the Internet. I can't claim that I am the sole writer of everything you see on those features of the Galileo web page. I borrow many ideas from many documents that describe Galileo's plans in more detail. And I have an excellent group of co-workers that reviews and suggests modifications to what I put together before it gets posted. It is truly the end result the work of many people, a true team effort.

It is quite fun to do, especially when you realize that the work you are doing is directly influencing how people view Galileo. We are presenting Galileo's achievements for the whole world to see! The most interesting part of this work, and most difficult, is being able to turn some highly technical mumbo-jumbo description into words that everyone can understand. When we do that, we have done our jobs well.

The other part of my job is helping to plan for the Galileo Europa Mission, the follow-on to the Galileo mission (which is scheduled to end in December of 1997). GEM, as we call the Galileo Europa Mission, will run for two years. All of its flybys will be of Europa, with a possible two flybys of Io at the very end. We are still waiting to find out if NASA will give us the final okay for GEM.

I am getting insight into an entirely different aspect of mission planning, namely, the trajectory and mission design. When I started working, on Galileo the spacecraft was already on its way to Jupiter. The orbital tour--Galileo's exact itinerary giving the distances and dates of the different satellite flybys-- had already been picked. Since the Galileo Europa Mission is essentially a new mission, a new orbital tour must be selected and the Project Science Group--the group of scientists who decide which science observations to make--must decide on a whole new set of observations and experiments.

At the same time, the tour designers and mission designers (that's me) begin to worry about what options are available for the Project Science Group to examine. This involves everything from available trajectories to spacecraft capabilities and resources (how much propellant do we have? how much radiation can we absorb before things start breaking down?) down to Deep Space Network antenna time (are there other spacecraft like Cassini or Mars Surveyer that will need DSN antenna time when we need it?). All of these areas (and many others) must be considered in designing a new mission.

One of the places these ideas are captured is in a document called a Mission Plan. And it is my job to put together the Galileo Europa Mission Mission Plan (it sounds funny, but both "Mission"s are supposed to be there). But much like the outreach and summary work that I do, I am only one of many contributors of the information that is placed in that document. Again, it is a team effort and it is part of my responsibility to make sure that all of the pieces fit together in a coherent manner.

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

For once I got up early before my husband. He actually slept in this morning while I fed our four cats. Four seems like a lot I know but the little monsters are all cute in their own way and they are distinctly different in their personalities. Osiris is a silver six year old tabby. She is hyper aggressive and acts like a tom cat or a small dog. She is the one that wakes you in the morning and is always into something. Charry is a six year old Russian blue with soft fur that feels like a rabbit's pelt. She is the dainty one. She is very lady like and a picky eater. In the morning she is always the last one to come to breakfast - in fact she has to have her own dish separate from the others. Yet she is the best hunter in the house and catches almost every bug that that comes in. The third indoor cat is Pookie. She is a neighborhood mongrel that was born on our doorstep three years ago. Her alternate name is TANK. This cat eats everything in sight and always comes back for more. All she does is eat and sleep! Our fourth cat is feral. She adopted us four years ago. She liked us so much that she had her kittens on our doorstep. (Yes, you guessed it. Pookie is her kitten.) We trapped the mama cat when we moved to our house. She did run away, but then three days later she was back hunting gophers in our yard, and has stayed ever since.

Some mornings we have visitors. This morning we had a troop of raccoons that helped themselves to Mama's food dish. They are really comical when they come knocking on the door in the mornings or early evening. We saw them as kits last year, and they are growing fast. I expect that they will go their separate ways soon instead of coming together all the time.

Tuesday, February 18, 1997
Even though the spacecraft is only flying its sixth orbit around Jupiter, we are now starting to get ready for the Callisto 9 (C9) orbit. It is a very complicated orbit and it will take a lot of planning. The teams will have a very strict schedule so that we will get the sequence finished in time to uplink to the spacecraft. We officially start our planning and file changing next Tuesday, so we are on our way to another sequence!

Part of my job for C9 is to get the files ready for the science coordinators. We do the initial planning for an orbit months in advance--and then we put it away "on the shelf." Not that there's really a shelf that we put things on; it's just that we don't look at it or think about it until we start getting near that orbit. It's now time for me to take those C9 plans off the shelf so that we can update them.

First, the commands get sorted so that each team only has to work with their set of information. There's no point in the solid state imaging people, for instance, looking at the commands that run the dust detector!

After everyone makes their changes, we will put all of the information and changes back together and see how the sequence looks. Usually, there are some new problems. For example, two instruments want to look at two different objects, but, because they are attached to the same platform, they need to look at the same place. Which target do you pick? This is the point where we closet ourselves in a meeting and hammer out any conflicts. It can take several days of intense bargaining before everything gets worked out.

Wednesday, February 19, 1997
Tomorrow is closest approach for the Europa 6 orbit. That means pizza party organization for me. For one party we had too many people who RSVP'd at the last minute, and we ran out of food. Not that food is the only attraction: several people are getting data down from the spacecraft so you get to know first hand how the encounter is going. A few times we have had our party during closest approach so we turn on the monitors and watch the Doppler data as the spacecraft passes the satellite.(I'll leave it to the Radio Science people to explain how Doppler works!)

Team webpages are becoming a constant in my life. It seems like there is always something to put on-line or update, like current information for our international scientists, and the final versions of the Europa 6 orbit planning products. There were over 220 science activities in this sequence!. Needless to say, getting that on the Web took up the rest of my day!

[Editor's Note: Duane is a Science Coordinator for the Dust Detector (DDS) and Magnetometer (MAG) instruments, two of the scientific instruments carried by Galileo.]

Tomorrow is the the E6 flyby of Europa. Galileo will whiz by Europa at less than 600 km above the surface. From my point of view as a coordinator for the magnetometer (MAG) and dust detector (DDS), it's the busiest day for us in the whole orbit. Here's what's going to happen:

At about 9:30 this morning (about 30 minutes from now) the dust detector (DDS) will be "reconfigured" (which means that certain settings on the instrument are changed). DDS is sensitive to certain kinds of radiation. This radiation becomes more intense the closer we get to Jupiter. At about 18 times the radius of Jupiter, the radiation is intense (strong) enough to cause problems for the DDS electronics. Basicially, it makes DDS think that it's measuring dust particle impacts when there is no dust around. It's like static on the radio interfering with your favorite song. Only in our case, the "music" is data about small dust particles around Jupiter. Reconfiguration helps to cut down on the static.

About 24 hours from now, at 8:00 tomorrow morning, the magnetometer (MAG) will also be reconfigured. Unlike DDS, it is not really bothered by the radiation. MAG is being reconfigured to account for changes in the strength of Jupiter's magnetic field. Like Earth, Jupiter has its own magnetic field. This field is generated deep inside Jupiter, and the closer Galileo gets to Jupiter, the stronger the magnetic field it feels.

MAG has several different sensitivity settings. It can measure small changes in magnetic fields, but only if the overall field strength is small. It also has a setting at which it can measure changes even if the field is very strong, close to the cloud tops of Jupiter. But in this setting, it can only detect relatively large changes in the magnetic field. And it has a third setting, somewhere between the other two.

You can think of the first setting as being like a small ruler, which you would use to measure things that are a few inches, or less than an inch across. The second setting is more like a long tape measure, which can measure the width of a room, or the distance between two houses on a block.

As we approach Europa, MAG will be set to its intermediate sensitivity.

At 8:37 am, data from MAG, DDS, and the other fields and particles instruments will begin to be recorded onto the tape recorder. Most of the time, these instruments send data to Earth, but at a low transmission rate. The instruments can make measurements at a much greater rate than Galileo can send the data back to Earth. So most of the time, they collect data, and then compress and edit it before sending it on to Earth. But now, for 45 minutes, all these instruments will collect their data and write it to Galileo's tape recorder at the highest possible resolution. In that 45 minutes, as we pass above the surface of Europa, we will collect as much data as we normally do in a week!

MAG will measure the changes in magnetic field strength and direction, and DDS will collect information on very small dust particles in the vicinity of icy Europa. It will take less than an hour to collect this data, but we will have to wait almost one month before we can play it back off the tape recorder and send it down to Earth. And it will take several days to play back data that took 45 minutes to record. I wonder what we'll find.

[Editor's Note: Duane is a Science Coordinator for the Dust Detector (DDS) and Magnetometer (MAG) instruments, two of the scientific instruments carried by Galileo.]

Yesterday, I wrote about Galileo's flyby of Europa, and the measurements that the magnetometer (MAG) and dust detector (DDS) will make as they fly by. Those measurements will be recorded onto Galileo's tape recorder starting about an hour from now. As I'm writing this, and throughout the day, Galileo's remote sensing instruments (e.g. the cameras) will be looking at Europa, at Jupiter's atmosphere, and at the other Galilean satellites.

But the magnetometer and the other fields and particles instruments are not quite finished for the day after Galileo has flown by Europa. These instruments will make another recorded observation, also for 45 minutes, starting at about 1 pm this afternoon.

Just a few minutes after our recorded flyby of Europa, MAG will need to be "reconfigured" (I talked about this process in my journal for yesterday, 3/19). This is because Galileo is venturing into the inner region of Jupiter's magnetosphere, where the magnetic field is very strong. The sensitivity of the magnetometer must be adjusted so that it can make accurate measurements.

Then, early this afternoon, Galileo will arrive at the point in its orbit where it is closest to Jupiter. In this orbit, we'll be about 580,000 km (360,000 miles) from the cloud tops of Jupiter. That's about one and a half times the distance from the Earth to the Moon. This may not seem "close" to Jupiter, but it is for Galileo.

"Why is that?" you might ask. Well, the complete explanation is a little bit complicated, but let me try anyway (if you get too confused, you can skip to the next to last paragraph in this journal to read the short answer). As you might know already, Jupiter has a very strong magnetic field. Jupiter's "magnetosphere" is the region of space. Inside this space, Jupiter's magnetic field is strong enough to deflect charged (ionized) particles that move outward from the Sun (these particles make up the "solar wind"). Earth also has a magnetosphere, which protects us from many of the effects of the solar wind. If the Earth didn't have a magnetosphere, we would probably not be here at all!

All of the Galilean satellites (Io, Europa, Ganymede, and Callisto) are found deep inside Jupiter's magnetosphere. This is important because of the constant volcanic eruptions on Io. These eruptions eject tons of material from Io into space. Once in space, Jupiter's radiation "ionizes" these small particles. When a particle is "ionized," it means that it now has an electric charge, either a positive charge or a negative charge. Magnetic fields can only affect charged particles, so now these particles from Io can be influenced by Jupiter's magnetic field.

Jupiter's magnetic field now tries to "grab" these particles. But the magnetic field and the particles are moving at different speeds. The particles are moving along with Io in its orbit, going once around Jupiter every 42 hours. Jupiter's magnetic field is rotating with Jupiter, so it spins completely around once every 10 hours. That means that Jupiter's magnetic field is moving about 20,000 miles per hour, or 5 miles per second faster than the particles ejected from Io! The result is a lot of interesting scientific phenomena which we would like to study.

Of course, it's not just the magnetic field and the slow particles that are involved. There are also particles that were picked up earlier, and that are moving along with Jupiter's magnetic field. The particles and their interactions form a doughnut-shaped region surrounding Io's orbit called the Io Torus. We would also like to study the Torus.

So what does all of this have to do with Galileo (which is still well over 100,000 miles away from Io) or with MAG? The interactions between the magnetic fields and the Io particles create radiation belts and a host of other phenomena that are unique to Jupiter. That radiation, which gets stronger as you get nearer to Jupiter, is a source of danger to Galileo. Too much of it can destroy electronic components, and render Galileo deaf and blind. Flying a mere 360,000 miles from Jupiter's cloud tops is therefore close enough!

At the same time, MAG and the other fields and particles instruments want to make measurements so that we can understand how Jupiter's magnetic field and Io's particles interact. So at 1 pm today, just as Galileo nears perijove (the point in its orbit that is closest to Jupiter), these instruments will record at their highest resolution for about 45 minutes. Although still far from Io, we will measure some of Io's effect on Jupiter's magnetosphere, and add to our understanding of the Io Torus.