Part 1: Webchat with NASA Galileo experts Wednesday, 3/26 at 2PM EST
Part 2: Testing software on a simulator before Galileo
Part 3: A bit of a celebration
Part 4: Subscribing/Unsubscribing: How to do it

A Webchat has been scheduled for this Wednesday, March 26th at 2PM EST. The chat will feature two experts from the Galileo team: Glenn Orton and Marcia Segura. These experts will be online for one hour to answer questions about looking at and interpreting scientific data.

The Webchat technology allows for an interactive chat online - - in real-time - - between the experts and the participants. The chat happens right in your browser window where you will be able to send in questions and get responses within a few seconds from an expert. All that is required to participate is a web browser that supports forms.

About the Experts:

Glenn Orton is a Co-Investigator for the Photopolarimeter-Radiometer, Net Flux Radiometer, and Nephelometer Experiments and Acting Chair, Atmospheres Working Group for remote sensing.

Marcia Segura is a science coordinator on the Galileo Near Infrared Mapping Spectrometer science team.

Marcia and Glenn both have bios and field journals online at
http://quest.arc.nasa.gov/galileo/bios/people.html

You should check out the bios and journals before the chat and prepare some questions for the experts. Topics for discussion/questions might include: looking at data, drawing conclusions, and the recent Europa 6 encounter.

The URL for Wednesday's chat is:
http://quest.arc.nasa.gov/galileo/webchat/galileo.html

The Europa encounter seems to be going OK so far, at least no problems yet. Of course, it's too early for me to see any realtime data results.

New "Phase-3" software test results, however, I *can* see (this is the software that would be used on the spacecraft if the tape recorder should break down). I made a really dumb mistake and kept the old memory write protection settings in the new software. Of course the new software caused write protect errors as soon as it started and would not run. I keep forgetting that the simulator that the development team used doesn't use the write protect settings and so doesn't show this mistake. Fortunately, it only took about a hour for me to figure out what was wrong, but the test will have to be restarted tomorrow. It's too long to finish today.

2-19-97
No one has called me about any problems on the spacecraft so things must still be running OK for the encounter. The schedule looks like more Jupiter science today then some Io science tonight. Europa science and closest approach is tomorrow morning. I'll take a look at the Web pages tomorrow morning and see what's up.

They restarted the Phase-3A testing on the testbed this morning and now the software seems to be running correctly. This test should answer the questions from last week about the CDS and the Solid State Imaging instrument working together properly , so I hope it runs to completion without crashing. I'm pretty sure that we will have to make some changes to the flight software based on these results and I want us to get started on them as soon as we can.

Meanwhile, we can start running the final acceptance tests that must be complete for the formal delivery of Phase-3A software in about three weeks. Formal delivery is a delivery of the software and its documentation to the Spacecraft Operations Team and the JPL Software Library. This cannot be done until a rigidly defined set of flight software tests and re-tests have been successfully completed by the development team and on the development team simulation tools. These acceptance tests essentially demonstrate that the delivered flight software will work properly when run on the spacecraft's Control and Data Subsystem (CDS).

We have also made Informal Deliveries to the system testbed in order to allow early testing of the CDS flight software's interaction with the other components (mostly the science instruments) of the spacecraft and their flight software. The "testbed," is basically a spacecraft hardware model consisting of developmental versions of the Control and DataSubsystem, the Attitude and Articulation Control Subsystem (AACS -- the Navigation computer), and the science instrument hardware connected together in the same manner as they are on the real spacecraft. Since the hardware is the closest available to the actual flight hardware (in some cases an identical spare) and the software is the same as that used on the spacecraft, the testbed gives us the best possible model of the way the things we are testing will behave on the Galileo Spacecraft. The testbed is complicated to run and can only run tests slowly, so we only test the way that the CDS flight software works with the hardware and software of the other spacecraft components on the testbed.

The majority of the CDS flight software testing is done on the CDS fast simulation system. This test system simulates the spacecraft hardware using software on a very fast computer. It is much faster and easier to run tests on this test system, but it does not have the real CDS, AACS or instrument hardware and does not have the real instrument software either. Only the CDS software and the AACS software are the same as what is on the spacecraft. Since the hardware is simulated in software, the tests do not have quite the same results as they would on the spacecraft. For example, as I mentioned above, the simulated hardware does not have write protected memory like the real hardware and so a simulator test does not show a write protection setting problem. For this reason, although most of the flight software functions can be tested on the simulator, some functions can only be tested on the testbed. We try to eliminate bugs before sending software to the testbed, but we can't always avoid the problems that crop up when our CDS software has to work with the software that runs other parts of the spacecraft.

Testing the software on the simulator is called subsystem or software integration testing because we are putting together all of the software parts of the Control and Data 'Subsystem' and testing them. Testing the software on the testbed is called testbed testing or system integration testing because we are putting together all the software and hardware on the testbed 'System' and testing how well it all works together. CDS Acceptance testing is normally done after subsystem integration testing and before system integration testing. For the Phase 3 software delivery we informally delivered the flight software before we completed the subsystem integration and the acceptance testing.

Since we did not complete as many of the pre-delivery imaging subsystem integration tests as we expected to, both the acceptance testing and the subsystem integration may also uncover more problems than we would normally expect. I think we'll probably need to make at least one more version of the flight software and test it before the formal delivery.

Same ol', Same ol'. You would think that I would change my routine at least a little bit! Read the mail, listen to voicemail and write journals.

Only five more orbits to go until we are done with the "nominal" (meaning planned) mission. Unfortunately an upcoming orbit will make us all want to quit early! Callisto 9 (C9, the ninth orbit, with a close encounter with Callisto) is going to be a development nightmare. This is because C9 is such a long orbit- -just about twice as long as the others. That means there are conflicts with other projects wanting to use the DSN (Deep Space Network), and problems with allocating spacecraft resources. Plus, we are planning to do something new when we play the data back. With C9 we are planning on having our recorded encounter, then play part of it back, then record AGAIN after we have cleared that part of the tape. It would almost be easier to start from scratch if we had the time. We have already started to "slip" the schedules (that is, push all our deadlines later) to accommodate delays, and we are cutting a fine line in getting commands to the spacecraft in time for the encounter on June 25th. It seems like such a long time away, yet we are already planning how to distribute the spacecraft's resources and timing during the encounter.

In addition, we are working on the two orbits before C9, Ganymede 7 and 8, but they seem almost simple because they are shorter and have been relatively free of conflicts. The rest of the day I worked on the Playback Rules document. I mentioned this once before in my journal for February 6th and look at how many things interrupted me before I got it pulled together!

Friday, February 21, 1997

Today we started out by having a meeting with our section group supervisor. This is considered our line management (which is different from our project management) and we don't actually see these individuals except during group meetings, evaluations, etc. They also sign our paychecks so it is worth being nice to them! :-) Our manager tries to bring in speakers from other projects on lab so that we can see what others are doing and where there may be jobs in the future after Galileo is finished. It is a unique perspective that most people never see. They either don't have group meetings, or they don't have a line management supervisor (because they charge directly to a task)

For lunch we had the Europa 6 Pizza party. There was over 35 people that came for pizza and we polished off 15 pizzas! Several people forgot so I had to comb the floors looking for them in their offices. (They were busy drooling over their data...) If you are late to one of these events you miss out on all of the food!

For the rest of the afternoon I worked on a new homepage design for the real-time science instruments. These are the fields and particles instruments that examine magnetic fields, dust, plasma, charged particles, etc etc.

Saturday, February 22, 1997
Sunday, February 23, 1997

This is the last weekend with my husband before he goes on a long over-seas trip for his company, so we did last minute shopping and planning for his trip. I fixed his favorite meals so that he could think of home when he was forced to eat airline food, and I baked him cookies to eat as snacks. He is a regular cookie monster and could easily finish all of the cookies in the house even if I baked every weekend. I also did my spring seed planting for my herb garden. I love fresh herbs when I cook so I planted all of the herbs that I use and some annual flowers as well to fill in the garden. It was a beautiful weekend to be outside. It was 70 to 80 degrees with a light breeze coming off the ridge. It felt great!