PART 1: Send your questions to be answered by Galileo experts
PART 2: Catching a mistake with the Galileo "Post Office"
PART 3: Documenting those who download the data
PART 4: Galileo returns to Europa for another close look
PART 5: Receiving news direct from NASA JPL about Galileo
PART 6: Subscribing/Unsubscribing: How to do it

The opportunity to send email questions to the men and women of the Galileo team is available now until early-April, 1997. In most cases, you will receive a direct reply within 10 days to two weeks.

We are grateful to the Galileo people for generously volunteering their time to support this service.

The sections below will describe some guidelines and procedures for the process.

K-12 students and teachers can email questions to researchers, engineers and support staff. This interaction will be supported by a "Smart Filter" which protects the professional from Internet overload by acting as a buffer. The actual email addresses of these experts will remain unlisted. Also, repetitive questions will be answered from an accumulating database of replies; thus the valued interaction with the experts will be saved for original questions. (More information about how you can directly search this database will follow later.)

TIPS FOR ASKING GOOD QUESTIONS

We recognize that this creates a gray area about whether or not a question is appropriate. Simply use your best judgment. Since the main idea is to excite students about the wonders of science and research, please err on the side of having the students participate. If you are not sure whether or not to send a question, send it!

Some teachers have used a group dynamic to refine the questions that they email to experts. For example, after first studying OFJ97 material, students divide into groups and create a few questions per group. All of the questions are then shared, and students are given an opportunity to find answers to their classmates' questions. Those that remain unanswered are sent to the OFJ97 team.

Ideally, the act of sending questions will further engage the students in their learning. It may help to think back to an early stage of development when the 3-year-old learns that repeating the word "why" can get parents to do most of the work in a conversation. The wise parent will try to get child involvement by asking, "Why do you want to know?" The same is true in the classroom. Teachers might want to help students to learn to ask good questions. Here are three questions the students might ask themselves as they submit their questions:

	What do I want to know?

	Is this information to be found in a resource I could
	easily check (such as a school encyclopedia)?

	Why do I want to know it? (What will I do with the
	information? or How will I use what I learn?)

The last question is the most interesting. Student reflection on why they want to know something is a very valuable learning experience.

LOGISTICS OF SENDING IN QUESTIONS (ADDRESS AND FORMAT)

question-jup@quest.arc.nasa.gov

We will acknowledge all questions immediately and answer as quickly as possible. In most cases we should be able to provide an answer within ten days to two weeks.

In the subject field, please put the letters "QA:" before a descriptive subject. Also, provide a sentence of background information to help the experts understand the grade level of your students. The following example should illustrate this idea.

TO:             question-jup@quest.arc.nasa.gov
FROM:           your email address
SUBJECT:        QA: People in control room
Hello,
I am an 8th grader from Mt.View, California. How many people normally
work in the control room monitoring the Galileo mission?

Thanks, Ferd Berferd

ONE QUESTION PER MESSAGE

TWENTY QUESTION LIMIT

THE QUESTION ARCHIVE

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

as the starting point.

[Editor's Note: Leo is a Sequence Integration Engineer and is responsible for integrating the commands for all the science instruments as well as the general spacecraft-related commands.]

Today was one of those days. Yesterday, I had released what was supposed to be the final version of the sequence of computer commands for the E6 (E for Europa, 6 for the sixth orbit) Encounter . It's been over two months since we started the development of the command sequence (the set of instructions that operate Galileo). And now at the end of the finish line, we've found a problem...yikes! Well, better catching the problem late than never.

I have a very challenging job on Galileo. I am the Sequence Integration Engineer or SIE on the E6 Encounter command sequence (or just "sequence" for short). I lead a group of 20-30 people to create a sequence which will collect the best data on Europa so far.

I also have the "birds eye" view of everything that happens on Galileo. I need that view, because I am responsible for piecing together hundreds of commands. Instead of a jigsaw puzzle, my end product is a command sequence that will maximize our mission objectives...ummm...without breaking anything. :-)

To do this, I first plan activities on the spacecraft that keep Galileo healthy. Then, I "integrate" or put together my commands with the commands that collect the science data. What we get is a listing, in time order, of all the commands that will be loaded into Galileo. This listing is then distributed to all of the members of the flight team. This includes the subsystem engineers (who are concerned with just one small part of the spacecraft, like power), the science representatives, and the navigators. All of us review the sequence, looking for mistakes.

The mistakes could be an isolated one, like commanding the camera to use a green filter instead of a red filter. Those are usually easy to fix. The mistake that we found involves more than one system. These are more complex. In our case, it involved two science instruments: the Extreme Ultraviolet Spectrometer (EUV) and the Heavy Ion Counter (HIC).

The EUV and HIC share a common data buffer. A data buffer is computer memory used to temporarily store data collected from an instrument. It's like using one mailbox, and one address, to store mail from two families. But in the case of EUV and HIC, only one "family" can use the mailbox at a time. You would have to tell the post office to deliver mail for the EUV family at say 10 am, and the HIC family to deliver at 2 pm.

In our mistake, HIC had told the central computer (our "post office") to deliver data (our "mail") before EUV was done (at "10 am" instead of "2 pm"). We wouldn't have broken anything on the spacecraft, but HIC would have lost some data.

Did we fix it? Yes, we did. It delayed our schedule a little, but it was still before we "uplink" or send the commands up to Galileo. The final step before we uplink the command sequence is to generate the the actual computer code that Galileo's central computer understands. Just like loading a program on your desktop computer, we load this into Galileo's central computer. Unlike your desktop computer, we do this with radio signals, hundreds of millions of miles away.

No one said flying a spacecraft at Jupiter is easy.

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

I don't know if you had a chance to read my biography yet, but my job is one that covers several tasks for the science and sequencing part of the Galileo project. I work with all of the science team, operators, and sequence products. In addition to that I also test software, archive materials for the team, and do some system engineering. At any one time I could be working on several diverse things that seem incongruous when put together in a journal! I think that my job is the one that crosses team organization and fills the gaps to help everyone out.

Today I started working on documenting the data playback rules and regulations. Basically the spacecraft is taking pictures, and science data and puts most of it on a tape recorder. Then after we are past our target (say a Jupiter moon), we play back the data that is on the tape. It sounds easy (especially if you have your own tape recorder or camcorder--how hard can it be to use one, even on a spacecraft?), but it is actually very complicated and we have people (known as coordinators) that make sure that the process is working correctly. They are constantly working on the next upcoming sequence or on data that is coming down so they don't have time to write down exactly what they are doing. That is where I come in. I am in the process of documenting what they do and how they do it so that others in the project know what to do if there is a new person or if there is a situation where we need to know what the spacecraft is doing. If someone gets sick, or moves to another project, the people left behind will then know exactly what to do.

After starting to work on the document, our project software programmer came in and said that he had two pieces of software ready for testing. This part of my job always takes precedence over other things because it will save the team time and energy to have software that is accurate and bug free. The testing of software is fairly easy. I take the software and pretend that I am a user and I run it through its paces. I do everything possible including running all of its printouts and reports, trying to get the software to "crash." After I am done testing the software I then compare the output from the new software to an error-free master copy of the output that I keep. This is a good check to make sure that no new bugs have been introduced with the changes. I then document all of the changes and write release notes for the team so that they know about the changes such as new commands or bug fixes that help them do their job. This is tedious yet necessary so that we have documentation of all of the changes that occur.

Another part of my job that I like is that of party organizer! When I was the project secretary I thought that it would be fun if we got together for potlucks or lunches at work. It has since grown! Now we have HUGE lunches to celebrate orbit encounters, because everyone on the team comes (even the project managers!). It is a celebration because we have done all of the work to command the spacecraft, and we are actually collecting data. Right now I am organizing a pizza party for our Europa 6 encounter which is Feb. 20th. There are 100 people on our team and that is a LOT of pizza!

NASA's Galileo spacecraft will make an encore appearance at Jupiter's icy moon, Europa, on Thursday, Feb. 20, marking the closest planned Europa flyby of the initial two-year mission.

The encounter will be Galileo's closest flyby yet of Europa. The craft will swoop past the Jovian moon at an altitude of 580 kilometers (360 miles) on Thursday, Feb. 20, at 9:06 a.m. Pacific time (12:06 p.m. Eastern time).

Galileo made its first pass of Europa in December 1996, revealing remarkable detail of that moon's terrain. This week's flyby will look at other areas of Europa's surface, which is covered by ice and a series of criss-crossed, dark lines. Europa holds great fascination for scientists because of the possibility that liquid oceans may be hidden underneath the icy surface. The presence of liquid water would boost the odds that Europa could host some form of life.

"I think this flyby may provide additional clues regarding the prospect of liquid water oceans on Europa," said Galileo Mission Director Bob Mitchell.

With its diameter of 3,138 kilometers (1,946 miles), Europa is just slightly smaller than Earth's moon. Because the geometry of the upcoming flyby will be somewhat different from the path taken by Galileo's previous Europa encounter, it will yield data and images of different portions of the moon.

"This position will allow for high resolution of different terrain," said Mitchell. "It will help us learn more about Europa's structure and surface and how the surface was formed."

The current Europa encounter phase began on Sunday, Feb. 16, and will continue through Saturday, Feb. 22. The spacecraft has already begun returning real-time encounter data, with recorded data scheduled to be transmitted to Earth beginning on the evening of Saturday, Feb. 22 (Pacific time).

This encounter will include the return of magnetospheric measurements from Europa's vicinity. Other science highlights will include the study of surface features of Europa's lineated regions, images of two other, smaller Jovian moons, Thebe and Amalthea, and studies of such Jovian atmospheric features as the south equatorial belt-zone boundary and the aurora borealis.

This flyby provides a period of radio occultation, when Europa crosses between Earth and Galileo, temporarily cutting off the spacecraft's radio signal. This affords a prime opportunity for Galileo to study atmospheric data just before and after radio contact is lost, when the signal passes through the Europa's atmosphere.

"As the fifth encounter in Galileo's series of 10 flybys, this marks the approximate halfway point for this series, which began in June 1996," said Galileo Project Manager Bill O'Neil. "It's been eight months since then, and it will be another eight months before the series' final encounter."

A third Europa flyby is planned for Nov. 6, 1997, and JPL has asked NASA to extend the Galileo mission by two years to include eight more Europa flybys and ultimately a flyby of Io. The proposed extended mission might be shortened if the spacecraft's operations were to deteriorate as a result of its continuous exposure to Jupiter's extreme radiation environment.

"NASA has assured us that the extended mission will be funded," said O'Neil. "The $30 million needed for the extension will come from within the existing NASA budget, enabled by cost savings due to improved efficiencies in JPL's spacecraft tracking and mission operations."

The 2,223-kilogram (2-1/2 ton) Galileo orbiter spacecraft was launched aboard Space Shuttle Atlantis on October 18, 1989. JPL manages the Galileo Project for NASA's Office of Space Science, Washington, D.C.

NASA's Jet Propulsion Laboratory maintains a mailing list for the Galileo project. The purpose of this list is to disseminate the latest status reports and press releases from the mission to Jupiter.

To subscribe to the galileo mailing list, send a note to:

majordomo@sender.jpl.nasa.gov

and place the following line in the body of your note:

subscribe galileo your-email-address

For example:

subscribe galileo jdoe@anyhost.edu