Monday, August 7, 2017

More Photos from Integration





My throne. 


Working on BABI at the Off Site Durham Scientific Ballooning Facility


Dan inspects BABI


Dan with a good looking GOAT


We realized, at the worst possible time, that one of our cables was wired incorrectly and had to rewire it so that we could test our payload.


Excited to actually attempt integration. Finally.


It's the North Cack, baby we're the boss. Carolina BBQ sauce with the slaw.


A very early morning after a very late night.


Kapton tape and a flat head screwdriver...the two items that are the toughest to find when you need them.


Dan and I visiting our friend Rosemary.



After so much time watching CSBF on the computer and so much effort spent trying to earn a trip to visit it, it was surreal to actually BE there.




Munir's photo face <3 


Jimmy giving pump down commands so that our SPEC sensors don't sploosh their guts all over the place. 


SPACE PUP!!! Heart eyes emoji.



A new look for Munir.


HASP and the BEMCO


One of my favorite parts of the trip was this badge. I could use it to get on base after hours and beep open doors.


A hang test in action.


Jimmy putting the finishing touches on GOAT for shipment to Fort Sumner.


Totally knackered student team lead.




Before


After!


Eat at Shep's.


A Jimmy's Eye View





On our way home!

Friday, August 4, 2017

Cleared for flight.

We have been (provisionally) cleared for flight. 

Whew.

The 'provisional' bit is due to our don't-use-the-pump "fix". We're content, even though we might be able to fix it with another heroic effort. We're a bit burned out, have neglected spouses etc. to tend to, and have school starting in a week, so we're buttoning the GOAT up for shipment to New Mexico for flight in a month.

-Jimmy

No one ever says "It's just like using an oscilloscope."

It has been quite a week.

We have spent two full days trying to figure out why our payload kept tripping the fuse. Startup current for our pump was popping the HASP fuse, so we've been trying a bunch of mitigation strategies: reservoir capacitors, a "slow start" to ease into our full current draw, installing our own fuse, and at one point we even considered flying a battery to even things out. None of them worked.

At this point in the project, the necessity of looking at our electrical profile under an oscilloscope became increasingly apparent to us. It seems obvious in retrospect, but given that none of us have ever done this before we can't be too hard on ourselves. To add a bit of insult to injury, the physics student and electrical engineering majors both needed to re-learn how to use one. ("There's a reason that the expression is 'just like riding a bicycle' and not 'just like using an oscilloscope'." -Julie) The LSU faculty were very accommodating. Actually, everyone's been amazingly accommodating. We've been swapping spare parts with the other teams in post-midnight hotel-room liaisons. The faculty advisor for UB spent hours going over our circuit diagrams for us and gave freely (thanks, Larry!) from his impressive stock of circuit components and gubbins.

Anyway, we discovered, once we re-learned how to use basic lab equipment, that our little pump is just noisy. as. hell.


This waveform isn't even from the initial surge required to get the pump going; this is what it looks like during regular operation. That little spike in the middle (it's kinda hard to see, but the darker line above the 'M' at the bottom) represents a few nanoseconds' worth of ~1.75 A draw. You may recall that we are fused to never exceed our current allotment of 0.5A. Our pump is blowing that out of the water, for very small time intervals, multiple times per second. We never noticed it through all our testing because we've been using standard multimeters, which don't register data at anything close to that level of fine resolution. We tried evening this out with some more circuitry magic, but weren't having any luck.

The upshot of all of this is that we decided to just leave our pump off permanently. We're not going to use it. Our payload is now chugging along happily without its centerpiece. The Bernoulli Air Bath Intensifier (BABI) will be as quiet and low-pressure as the rest of the payload. This is sad and disappointing, but vastly better than flying a brick of non-functional electronics, which in turn is worlds better than not flying at all. We passed pre-integration and integration again, GOAT is hanging out in the vacuum chamber now, and we're about to start chilling for the first part of the thermal test.

It's going to be a wonderfully slow day compared to the shrieking half-blind anxiety of the last few. We're updating our documentation, reading, and chatting with the other teams. If this goes well, then we will truly have reached the end of the work for this project. That's quite a feeling.

In celebration, permit me to share with you a picture of our electrical/software lead airing his feet out after a long day in the high-bay:



-Jimmy

Wednesday, August 2, 2017

Integration, Day 3

Monday we spent all day trying to re-factor the payload. (ALL. DAY.)

Tuesday we fixed things, scraped it together, and got integrated onto the gondola with only a couple hours left in the window.

Today we watched them load the gondola into the vacuum chamber (the 'Bemco') with a forklift. They then pumped it down, chilled it with liquid nitrogen, and pumped down again. Once we pumped below 100 millibar (a tenth of usual sea level atmospheric pressure) our 15 minute pump timer started ticking. 14 minutes and 30 seconds went by with good data coming down the pipe.



Then we died.

Current working theory is that we blew a fuse when the pump turned on. We're preparing some mitigation strategies but we don't get our hands back on the hardware for at least 2 more hours. Then, even when we fix the issue, we're gonna have to start all over again with pre-integration. We get one more shot at this on Friday. If we fail that then we can still fly, but we'd have to do some kind of tests on our own to prove to them that things aren't going to fail horribly. This is undesirable for many reasons, one of which is that this involves a lot more work.

The team is running out for food and then we'll see where we stand. For now, enjoy some pretty plots.
-Jimmy



Tuesday, August 1, 2017

We

Integrated!!!

Here we go

Everything is together

Aaaaaaaaaaaaa

oh sweet spacecat we're almost there aaaaaaaa we're almost there

DanK figured out a software issue that was making our sensors all wacky. We've put the GOAT together and... it's alive. We're reading out data. Our wiring is an embarrassment and we're exhausted, but it works. Holy wow. We're closing up and are minutes away from pre-integration.

For those of you not familiar with ballooning protocols, pre-integration is the checklist we go through before integration. Post any questions you may have about this in the comments section and I'll try to explain it.

Please keep sending good thoughts, Tootsie Rolls, and benevolent spells. I love you all.

It's always darkest before the...noon

Last night was a doozie. The rewire took longer than expected...longer than pi even...and the boys to men were awake until about 7 AM. After a few hours of sleep and a few hot showers they were back in action. We had a glum "weather briefing" and made the choice to sweat for another hour and then pack up to go CSBF and update Guzik. And theeeeennnn DanK solved the problem!! And we loaded up the van moved to Beverly. The drive was raucous. Now we're at CSBF assembling the GOAT. Spacecatspeed Space GOAT.

Having issues.

07:09 local time. Been wiring and debugging since 08:00. Need a couple hours of sleep before trying again. Not looking great right now.

It's 3 AM somewhere

Not here. Wrong time zone.