The main issue we've been dealing with here in these last few days of having an integrated experiment is making sure we can downlink data reliably through CSBF hardware. Obviously, while in flight, we can't have any cables connected to the gondola to carry our data down, so we rely on CSBF to provide various sorts of telemetry links (a line-of-sight high-rate 1Mbps transmitter, a 92 kbps TDRSS high-rate transmitter, a 6 kpbs TDRSS low-rate transmitter, and a very slow Iridium system). The challenge for our software is to be able to deal with these data streams whose data rates vary hugely along with a dynamic allocation of which data we want to see over these streams and their update rates, which we plan to vary during the course of the flight (for example, during fridge cycles we want to make sure to downlink all of the fridge-related data, but all of those data are not super important when we're taking science data. So we need to be able to choose which channels to downlink when in order to optimize getting the most relevant data at a given time over our limited data rate connection).
So...this is hard. And it mostly works! But not quite completely. So the order of business for the past few days has been to try and work with this system as much as possible to try and work out the kinks so we (meaning Seth, our resident expert on this software who has left Palestine and is now working remotely) can get working downlinks. Still a work in progress.
Simultaneously, the gondola is slowly being disassembled as much as possible in preparation for the full disassembly. Today, Britt and Michele removed the flight power system and we went back to a scaled-down system so they can take the gondola legs off tomorrow.
Jeff and I also made progress in preparing to repeat a calibration experiment we did a couple days ago. The previous test seems to provide meaningful results, but the signal-to-noise ratio is a little low. We've thought about the experiment a little more and have devised a way to increase the signal in the experiment and have laid the groundwork for making this happen tomorrow first thing.
No pictures today.
No
Sunday, August 26, 2012
Saturday, August 25, 2012
Day 89, 8/25/2012 -- Packing begins
Kind of another grab bag of things going on today -- we have started to do some packing in earnest today, loading some of the larger crates (mirrors, in particular) into the CSBF cubical sea shipping containers. Michele also completed the removal of the LCS from the gondola -- it's basically at the bare minimum in terms of the hardware needed to do a realistic flight simulation.
Speaking of flight simulations, the bolo crew attempted another "launch/ascent" simulation today after the fridge cycle ended. Today's was more successful, but was hindered by our downlink software crashing often. This turned out to have been a disk issue, and replacing the downlink relay computer's hard drive with a fast solid-state drive seems to have fixed the issue.
We found another issue, though, possibly caused by our poking around in the power crate yesterday to fix the heater problem, so we have to investigate a little more tomorrow.
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120825
Speaking of flight simulations, the bolo crew attempted another "launch/ascent" simulation today after the fridge cycle ended. Today's was more successful, but was hindered by our downlink software crashing often. This turned out to have been a disk issue, and replacing the downlink relay computer's hard drive with a fast solid-state drive seems to have fixed the issue.
We found another issue, though, possibly caused by our poking around in the power crate yesterday to fix the heater problem, so we have to investigate a little more tomorrow.
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120825
Friday, August 24, 2012
Day 88, 8/24/2012 -- Flight simulations, take 1
We started off today with a discussion of the procedure and goals for our flight simulations, which will take up a majority of the time we have upcoming before we disassemble the gondola. After a roughly 2.5 hour discussion, we came up with a plan -- which, as the best laid plans often do, went awry.
We were stymied by a peculiar failure of our fridge heater channels, which was that they wouldn't heat. After going through the likely culprits on the software and heater power distribution end, we determined the problem was localized to the DC/DC converters that generate the appropriate voltages for the heaters. So, Shaul and I removed the power crate containing said DC/DCs, poked around inside a little bit, pored over schematics, and finally found a solution that works despite it being specifically something that the schematics and what meager documentation exist say explicitly should NOT work. BUT...it actually works in the way that we had wanted it to work in the first place, so we're not complaining. Now at 11:30PM, we just started a fridge cycle so the detectors will be ready to go by the morning's attempt at another flight simulation.
In other news, Michele tested our other solar array, and now both arrays have been disassembled and the panels safely packed into their shipping crates. He and Britt, who arrived back in Palestine today, also swapped out our elevation actuator to our other actuator just to confirm that it works after degreasing with low-temp grease -- and it turns out it works better than the first de/regreased one! We also got some parts back from the powdercoater that we had done at the same time CSBF had some of their parts done.
Pictures from today (just a few powdercoated parts):
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120824
We were stymied by a peculiar failure of our fridge heater channels, which was that they wouldn't heat. After going through the likely culprits on the software and heater power distribution end, we determined the problem was localized to the DC/DC converters that generate the appropriate voltages for the heaters. So, Shaul and I removed the power crate containing said DC/DCs, poked around inside a little bit, pored over schematics, and finally found a solution that works despite it being specifically something that the schematics and what meager documentation exist say explicitly should NOT work. BUT...it actually works in the way that we had wanted it to work in the first place, so we're not complaining. Now at 11:30PM, we just started a fridge cycle so the detectors will be ready to go by the morning's attempt at another flight simulation.
In other news, Michele tested our other solar array, and now both arrays have been disassembled and the panels safely packed into their shipping crates. He and Britt, who arrived back in Palestine today, also swapped out our elevation actuator to our other actuator just to confirm that it works after degreasing with low-temp grease -- and it turns out it works better than the first de/regreased one! We also got some parts back from the powdercoater that we had done at the same time CSBF had some of their parts done.
Pictures from today (just a few powdercoated parts):
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120824
Thursday, August 23, 2012
Day 87, 8/23/2012 -- Odds and Ends, part 2
This morning I drove Kyle to Dallas so he could go home for a weekend trip he had planned for some time. While I was gone, Jeff managed to get the BTS completely disassembled while Michele did a test of one of our two solar arrays (the second will happen tomorrow).
After I returned from Dallas in the afternoon, Jeff did a "quick" test that will help us be confident of the optics and polarization alignment in Antarctica where we won't be able to do scans of a polarized source on a water tower. When I say "quick", I mean, of course, it took 4 hours, but that's not bad for a test whose barest idea was the only thing that existed before today -- we worked out all the details, did the entire setup, and took all the data in those 4 hours. A nice productive way to end the day.
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120823
After I returned from Dallas in the afternoon, Jeff did a "quick" test that will help us be confident of the optics and polarization alignment in Antarctica where we won't be able to do scans of a polarized source on a water tower. When I say "quick", I mean, of course, it took 4 hours, but that's not bad for a test whose barest idea was the only thing that existed before today -- we worked out all the details, did the entire setup, and took all the data in those 4 hours. A nice productive way to end the day.
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120823
Wednesday, August 22, 2012
Day 86, 8/22/2012 -- Odds and ends
We continue to check items off our list and prepare the experiment for shipping to Antarctica. In the morning, our SIP was removed from the gondola, so now we are operating through the SIP simulator. This afternoon, Michele, Kyle, Jeff, and I removed the two mirrors from the gondola as they are no longer needed for any of the tests we plan to do. Shaul, Michele, and I then did a full and thorough test of our lock pin system after Shaul and Joy spent some time in the morning figuring out some of the preliminaries.
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120822
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120822
Tuesday, August 21, 2012
Day 85, 8/21/2012 -- EBEX, now with 100% less BTS!
Today we ticked a few of the miscellaneous items off our pre-disassembly to-do list. Jeff and Kyle tested some HWP system commands, Shaul and I did measurements of our mirror positions at different elevation angles, and Kevin and Kate took more detector noise data. Kyle also started setting up the SIP simulator, which we will use once CSBF removes the SIP from the gondola for thermal vac testing.
On the disassembly front, we started removing some more of the major sub-assemblies of the experiment. I forgot to mention that yesterday we removed the radiator panels for our detector electronics liquid cooling system. Today, we removed the Baffle/Triangle Support (BTS), the tubular frame that surrounds the whole experiment and provides a structure which we will cover with aluminized mylar in Antarctica. Once the antennae from the top of the BTS are disconnected and removed by CSBF, we can disassemble the BTS and start packing our large shipping container.
On a slightly different note, I was able to fix the BLAST group's helium leak checker with help from a gentleman at Laco Technologies -- we were video chatting via Skype and he was able to diagnose the problem immediately, within seconds of the leak checker turning on. He guided me through the repair process and a half hour later we had a working leak checker. Good thing too, because otherwise we would have had to rent one at considerable expense.
Pictures from today:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120821
On the disassembly front, we started removing some more of the major sub-assemblies of the experiment. I forgot to mention that yesterday we removed the radiator panels for our detector electronics liquid cooling system. Today, we removed the Baffle/Triangle Support (BTS), the tubular frame that surrounds the whole experiment and provides a structure which we will cover with aluminized mylar in Antarctica. Once the antennae from the top of the BTS are disconnected and removed by CSBF, we can disassemble the BTS and start packing our large shipping container.
On a slightly different note, I was able to fix the BLAST group's helium leak checker with help from a gentleman at Laco Technologies -- we were video chatting via Skype and he was able to diagnose the problem immediately, within seconds of the leak checker turning on. He guided me through the repair process and a half hour later we had a working leak checker. Good thing too, because otherwise we would have had to rent one at considerable expense.
Pictures from today:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120821
Monday, August 20, 2012
Day 84, 8/20/2012 -- Gold, Frankincense, and MRR
We finished our compatibility test just in time for the Antarctic LDB Mission Readiness Review, or MRR, this morning. As part of this review, the science payloads going to the ice have presentations on their status and various other issues (personnel, schedules, etc) pertinent to their campaigns. EBEX's review went well, and we fully expect to have no problems once we get to McMurdo (hey, we can dream, right?).
After the MRR, we had a discussion about the remaining outstanding items to test before we disassemble and start packing up the experiment to ship. There is a range of pointing (and especially star camera) related stuff as well as a few smaller receiver/telescope items on the list along with further analysis of our detector array's performance.
One of the items on the list was more time constant measurements -- during our previous measurements, we only took data in our lowest frequency band, so we wanted to extend that up into the higher bands. Also, our previous measurements showed some weirdness so we changed the source modulation to try and figure out the source of the problem. It turns out that changing the modulation from an electrical chop of our narrowband source to a mechanical chop of the source with an interrupter wheel made it so we could make measurements at all three bands simultaneously! The data from this test look promising.
As part of this test, I had to climb up and down the gondola quite a bit, and at this point I'm getting pretty good at it.
No pictures today.
After the MRR, we had a discussion about the remaining outstanding items to test before we disassemble and start packing up the experiment to ship. There is a range of pointing (and especially star camera) related stuff as well as a few smaller receiver/telescope items on the list along with further analysis of our detector array's performance.
One of the items on the list was more time constant measurements -- during our previous measurements, we only took data in our lowest frequency band, so we wanted to extend that up into the higher bands. Also, our previous measurements showed some weirdness so we changed the source modulation to try and figure out the source of the problem. It turns out that changing the modulation from an electrical chop of our narrowband source to a mechanical chop of the source with an interrupter wheel made it so we could make measurements at all three bands simultaneously! The data from this test look promising.
As part of this test, I had to climb up and down the gondola quite a bit, and at this point I'm getting pretty good at it.
No pictures today.
Sunday, August 19, 2012
Day 83, 8/19/2012 -- Compatible Now
After many days of testing, EBEX has finally passed its compatibility testing. Yesterday we gambled with the weather, trying to squeeze in whatever testing we could in between breaks in the weather. We got most things done yesterday, but since we didn't finish we left EBEX in the "Tim Shed", the large open building where the launch vehicle parks. Conveniently, we still had line-of-sight uplink/downlink, so the pointing crew was able to do some things overnight (though not actually point the gondola).
We awoke this morning to an absolutely beautiful summer day, with clear blue skies and quite moderate temperatures. Since the gondola was already hanging from the launch vehicle, it was quick business to disconnect from wall power and get the gondola moving. We parked outside the high bay and we finished with the "compatibility" part of the day by about 10 or 10:30AM. We then continued to hang while Chappy and Joy did some pointing test, we took some sun sensor calibration data, and Matt and Michele tried to diagnose an odd problem with the liquid cooling system pump motors. Still, we were back in the high bay by 2 PM, at which point we refilled all the cryogens in the cryostat and began a fridge cycle.
Pictures from yesterday:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120818
Pictures from today:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120819
We awoke this morning to an absolutely beautiful summer day, with clear blue skies and quite moderate temperatures. Since the gondola was already hanging from the launch vehicle, it was quick business to disconnect from wall power and get the gondola moving. We parked outside the high bay and we finished with the "compatibility" part of the day by about 10 or 10:30AM. We then continued to hang while Chappy and Joy did some pointing test, we took some sun sensor calibration data, and Matt and Michele tried to diagnose an odd problem with the liquid cooling system pump motors. Still, we were back in the high bay by 2 PM, at which point we refilled all the cryogens in the cryostat and began a fridge cycle.
Pictures from yesterday:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120818
Pictures from today:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120819
Saturday, August 18, 2012
Day 81, 8/17/2012 -- Compatibility, soon?
Sorry for the late update...CSBF got their SIP issues worked out and told us they were ready to try again for compatibility Saturday morning. During the day we managed to keep ourselves occupied.
Now it's Saturday morning and it's raining and thundering all over the place. We're waiting for a break in the weather, perhaps in a few hours, where we'll get a window to roll out.
No pictures this update.
Now it's Saturday morning and it's raining and thundering all over the place. We're waiting for a break in the weather, perhaps in a few hours, where we'll get a window to roll out.
No pictures this update.
Thursday, August 16, 2012
Day 80, 8/16/2012 -- Compatibility, brought to you by goldfish crackers, big marshmallows, and Coca Cola
Wow, what a long day. As of now I've been up for about 35 of the last 38 hours trying to help facilitate our compatibility test. In the end, we ran out of time due to some nagging issues with the CSBF hardware, but we made a lot of good progress and hopefully will be able to complete our compatibility testing in a few days once the hardware is ready and the weather cooperates.
I'm not going to post a detailed run-down, but I do have a lot of pictures ranging from our 10AM to solar panel tests to our pickup at 10PM to various parts of our rollout to being set out on the pad at about 5AM the next day (today). I don't have any pictures from after that, but it looked pretty much the same the whole time, and the night-time shots are more dramatic anyway :)
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120815
I'm not going to post a detailed run-down, but I do have a lot of pictures ranging from our 10AM to solar panel tests to our pickup at 10PM to various parts of our rollout to being set out on the pad at about 5AM the next day (today). I don't have any pictures from after that, but it looked pretty much the same the whole time, and the night-time shots are more dramatic anyway :)
Pictures:
https://picasaweb.google.com/104253244018605213307/EBEXInPalestine20120815
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