Friday, August 31, 2012

Day 95, 8/31/2012 -- Break it down

Today Kyle and I opened up the cryostat and started the disassembly and shipping preparations for the cold stuff -- removing SQUID controller boards, SQUID mounting boards, the instrument insert, and the half-wave-plate system. Kyle spent most of the afternoon then disassembling the instrument RF-shielded wiring towers while I disassembled and packed the half-wave-plate system.

On the north side of the high bay, the Columbians were hard at work packing up all of their stuff to be packed into shipping containers. In the afternoon, Britt was able to piggyback on one of the CSBF Bemco tests and verify that the new power system isolation diodes were sufficiently-well heatsunk -- and they were, to the tune of a 60-degree safety margin!


Day 94, 8/30/2012 -- High cube packed

The high cube container with most of the gondola bits is packed and ready for fumigation (Friday) and shipping to Port Hueneme (Saturday) for its eventual date with a boat -- and it was done about 20 hours ahead of schedule!

The gondola team has started packing up their equipment and have made a fair amount of progress. We still have to wait until the cryostat is warmed and fully prepared for shipping, as we will likely need many of the tools and other supplies as we do that. Still, Kyle successfully manged to get our CANBus programs working on his laptop and we made some wiring, both of which will help facilitate our Bemco tests next week.


Wednesday, August 29, 2012

Day 93, 8/29/2012 -- Pack it up, pack it in, let me begin

Today we made a massive amount of progress in packing the experiment for shipping. We started early -- Britt and Michele at 6:30AM -- to get the gondola ready for the removal of the cryostat and the disassembly of the inner/outer frames. Kyle and I showed up at 7:30 to assist with cryostat removal, which went very smoothly.

After that, we then got the inner frame removed from atop the outer frame and set on the ground. At that point, Kyle and I went to attend to some matters with the cryostat (empyting its helium tank of liquid nitrogen to allow it to warm up further, backfilling with nitrogen gas, and wrapping the exterior with heater straps) while Britt and Michele proceeded to remove components from the gondola (flight computers, cables, sensors, etc).

Once Kyle and I finished the immediate cryostat work, I went back over to the gondola to assist in the disassembly whilst Kyle immersed himself in the vagaries of CANBus on Linux in preparation for our upcoming Bemco testing of various components.

Michele, Matt, and Kevin then left a little after 11AM; Britt and I then continued working on gondola disassembly and awaited the arrival of the riggers to assist us in loading the inner and outer frames into our large shipping container. They arrived around 12:45 and we had both large pieces plus the "triangle" spreader bar loaded into the container by 1:45, give or take a few minutes.

Britt and I continued to load things into the container for the remainder of the day. Kyle took a break from CANBus around 4PM to fill the helium tank with warm water to accelerate its warming, which causes it to reach 273K (ice water temperature) nearly instantly. The cryostat has been left to complete its warming overnight.


Tuesday, August 28, 2012

Day 92, 8/28/2012 -- Warm it up, Kris

Another busy day in the high bay as we prepare to pack up and ship the experiment to the ice. First Kevin and I took a little bit more data through our downlink system at various rates while scanning to get a handle on how to deal with our signals as we will see them. Then, I regripped the half-wave plate and boiled off the rest of the helium in the tank. In order to warm up the instrument as quickly as possible, we then refilled the tank with liquid nitrogen to bring it up to 77K nearly immediately. The internals of the system (the lenses and detectors, mostly) still have to warm up, so we left it at 77K for the rest of the night.

We then removed all of the detector readout electronics and associated hardware from the gondola in preparation for the removal of the cryostat tomorrow and the disassembly of the inner/outer frame.

No pictures today, and likely not many for the next few days -- we're facing a pretty tight shipping deadline for our large shipping container (Friday!) and it has to have ALL of the large gondola items in it before it leaves. I'll try, though!

Monday, August 27, 2012

Day 91, 8/27/2012 -- Get low

Today was a pretty busy day for us in the high bay. First thing in the morning, Jeff and I added a little bit of liquid helium to the cryostat so it didn't run out during the day. We then helped Michele remove the legs off the gondola to bring it down to a more manageable height to help facilitate the testing we were planning on doing during the day.

We then set up some hardware above the cryostat in order to repeat an experiment we did a few days back but hopefully get higher signal to noise -- and boy, did we ever. Our previous attempt used a small, millimeter-wave-absorptive chopper blade that alternately covered and uncovered a bit of bare aluminum, and gave us a small but measurable signal. This time, we had a big absorptive chopper blade that repeatedly eclipsed a large styrofoam cooler filled with absorber and liquid nitrogen. Instead of a few tens to a hundred counts of signal, we saw a thousand, and we clearly saw signals in every detector. So we set up our first experiment and then went to lunch.

Over lunch, Michele, Jeff, and I talked with a member of the SuperTIGER team about his experience recovering another payload, BESS, that had a similarly large and unwieldy main element -- in our case, the cryostat; in theirs, their magnet. It was an enlightening experience -- especially the part where he said they camped on the ice for 13 days while they disassembled the experiment!

Of course, having such a huge signal-to-noise can be a blessing and a curse, because then you can imagine many other experiments to do with more or less the same setup -- so what we had planned to be a 2-3 hour experiment ended up lasting the whole day as we did various incarnations of the experiments.

Matt was kind enough to organize a grillin' out on the patio area at CSBF and took it upon himself to cook and otherwise prepare a nice little social gathering before many people leave tomorrow.


Bonus video (albeit overexposed and with jerky zooming and focusing) of the big chopper blade spinning:

Sunday, August 26, 2012

Day 90, 8/26/2012 -- Downlink demons

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.


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.


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. 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):

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.


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.


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:

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.

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:

Pictures from today:

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.

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 :)


Day 79, 8/15/2012 -- Compatibility, ongoing

Short update today: We're currently in the middle of our compatibility checkout (at nearly 6AM after having started at 9PM or so). I'll give details and post lots of pictures later...presumably after I will have gotten some sleep sometime today.

Tuesday, August 14, 2012

Day 78, 8/14/2012 -- Weigh Day

Today was another productive day in the EBEX universe. We did some more noise tests, we got the battery commanding system working (our batteries are a little different than normal batteries, and have some internal circuitry that we can interface to), and we weighed the experiment for the first time in who knows how long. Right now it's looking like we'll be about 100 lbs under our weight limit -- not bad!

Tonight will be the last (hopefully) of our water tower scans. We attempt compatibility (weather permitting) starting tomorrow night.

No pictures today.

Monday, August 13, 2012

Day 77, 8/13/2012 -- The only constant is change

Today, I didn't have to climb anything once! Kate spent some time climbing on the gondola to debug some DfMUX board issues while I bounced around doing various things and talking to people about our upcoming compatibility test and some issues for our Antarctic campaign. Toward the end of the day, we took some more time constant test data with our chopped source.

Andrei was a veritable one-man beehive of activity today as he tried to finish the mounting of the liquid cooling system radiators before he left today to catch a red-eye back to Rhode Island. And he succeeded, I might add!

I have uploaded some pictures from yesterday and put the link in yesterday's post -- go there if you want to see 'em!

Pictures from today:

Day 76, 8/12/2012 -- Up and down

Up and down in the very literal sense, for me anyway. I spent most of today climbing up into and down from the gondola to help Kevin and Kate with some measurements they were doing, and then at the end of the day had the joy of climbing the water tower with Jeff with a 30-lb power supply in my backpack and then hanging out up there for the next 3 hours. It was a productive, but very long (10:30AM to 3AM) day at the base. In fact, I should be asleep, but I needed to write this post first!

Elsewhere in the high, Michele spent a lot of time making a power cable for us to use while we are hanging from the launch vehicle, and Andrei made a lot of progress in the mechanical mounting for the liquid cooling system radiators.

I have pictures, but I'm too tired to deal with them right now so I'll post them tomorrow (later today, actually).

EDIT: Pictures!

Saturday, August 11, 2012

Day 75, 8/11/2012 -- Like lotto, you got to be in it to win it

I don't know why that line came into my head -- perhaps it's because I'm quite sleep-deprived, having woken up at about 4:30AM in order to catch my early flight from Minnesota down to Texas. Of course, this means I'm back in Palestine!

A lot has happened in the nearly 3 weeks I've been gone. Many many scans have been made of the source on the water tower, whose data are helping us understand the EBEX optics. The big push right now is to do our "compatibility test" with CSBF to ensure their and our systems play nice with each other. There has been a ton of activity over the past few weeks that I've missed out on, but the gondola itself hasn't changed too much -- the solar panels are now wired up and installed, some components for the liquid cooling system have been mounted, and basically all hardware is in place for compatibility. We're going to try and take some more data in the next couple days and then switch over completely to doing our compatibility test.

Elsewhere, the BLAST team has done their compatibility test and have basically disassembled and packed up their entire experiment. They did, however, implement a fix in their cryostat and are now checking to see if it worked, but it's likely they won't be here for more than about a week.