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Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all,

Telecon tomorrow (June 20 in North America, June 21 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 23.00 European, 7 am Eastern Australia). Lots of updates on drop testing, on testing of the OSI and Hamamatsu photodiodes with the new amplifier boards, and on new updates on AIFCOMSS station-keeping prediction/simulation software. More discussion items for tomorrow's telecon include: flight/telescope plans and tests; construction and lab tests of the new gondola/payload; light sources and light source modelling; goniometric and pre- and post-flight calibration; propulsion work; nanosat bus and payload solid models; computing / website / TWiki forums and e-mails; grant applications; and recap of schedules. I'll send an update with a bunch of recent photos, etc, before the telecon tomorrow.

Here's how to connect:

1) Open Skype on your computer (note that of course, you should first install Skype, http://www.skype.com, on your machine if you haven't already).

2) In the "Contacts" menu, add me ( jalbertuvic ) as a contact, if you haven't already.

3) Just wait for me to Skype-call you at the usual time (5 pm Eastern, 2 pm Pacific, etc).

4) If there is any trouble, or if you don't get a Skype-call for some reason and would like to join, please just send me an e-mail (jalbert@uvicNOSPAMPLEASE.ca).

Here's the tentative agenda:

I) Flight & telescope plans, and upcoming tests

II) Construction, drop tests, and other tests of the new gondola and payload

III) Diffused light source and its modelling, pre- and post-flight calibration, and goniometric calibrations

IV) Solid modelling

V) Computing/website, including recent flight control and simulation progress

VI) Grant applications


Talk to you all tomorrow, thanks!!!


-- jalbert - 2019-06-19

Hi all!

Apologies for the delay! -- here's a quick update on ALTAIR balloon work over the past 3 weeks, minutes of the meeting 3 weeks ago (attendees Arnold Gaertner [NRC] and me), and a reminder of the telecon in 30 minutes(!) from now:

Andrew Macdonald in the phys & astro electronics shop here has been testing different photodiodes with the new precision photodiode amplifier boards. Here are the first two linearity plots he made a couple of weeks ago using a Thorlabs FDS100 with two different laser diode sources (a 780 nm one and a 650 nm one) and two different preamplifier transimpedence gain settings on the board (10k and 1M):

And below is his first linearity comparison between two different photodiodes (that he made last week): the Thorlabs FDS100 (same as in the above plots) in the first plot below, and one of our OSI Optoelectronics UV-015 photodiodes in the second plot below (both with and without reverse biasing):

As you can see, the FDS100 looks nice and linear (in the first of the two plots above), whereas the UV-015 (in the second of the two plots above), not so much... That might conceivably be because the UV-015 is sensitivity-enhanced for (and thus intended for) the blue and near-UV range of the spectrum, whereas the laser diode used for both of the above plots was a 780 nm near-IR one. In terms of bare laser diodes, that 780 nm and a 650 nm one are the only two we happen to have here, so I just purchased a 405 nm one: https://www.digikey.ca/product-detail/en/us-lasers-inc/D405-120/38-1035-ND/3438595 in order to see if the UV-015 might hopefully behave in a more linear way with 405 nm light. Andrew will do that test when he gets back next week. Following that test, Andrew will see if the UV-015 still works and behaves nominally after I knock out its window using the hammer-and-awl method I mentioned in the last minutes, and also he'll test our windowless Hamamatsu S2386-8K photodiodes. (He'll do those latter two tests in a clean room, in order to hopefully avoid damaging windowless photodiodes.)

As mentioned last week, we had our first successful dummy-payload drop test using the new outdoor drop testing pole setup last Wednesday (video at https://wiki.heprc.uvic.ca/twiki/pub/Forum/ForumGeneral0030/ALTAIR12jun19SuccessfulDummyOutdoorDropTest.MOV ). We're going to try another dummy-payload drop test this afternoon right after the telecon. (We want to do as many of these drop tests as possible, to see which configurations of the parafoil on the triangular rigging support consistently work in making the parafoil open as quickly as possible following cutdown, and which ones consistently fail. It has been quite windy here though this past week, so we haven't done any more since the one last Wednesday.) Eventually we'll of course do outdoor drop tests of the real payload (instead of this dummy one) with this outdoor drop testing pole setup, but first we'll need to install the new photodiode amplifier boards into the payload, and before doing that, Andrew needs to finish his tests (mentioned in the previous paragraph) of the different photodiodes with those new boards.

Summer students Afif and Logan are additionally working on AIFCOMSS flight path prediction at present.

The survey-tripod-mounted device to cross-check yaw-pitch-roll information from the gondola (e.g., on days before/after flights) is also constructed now, thanks to Mark Lenckowski -- photo at:

and all that remains to be done is to finish the small fitting between the device and the bottom of the payload. The purchased hardware in it includes both the survey tripod (http://www.cpotools.com/cst-berger-60-alwi20-o-aluminum-tripod-with-quick-release--orange-/cstn60-alwi20-o,default,pd.html), two adjustable angle mounts (http://www.thorlabs.com/thorproduct.cfm?partnumber=AP180), and a rotation mount (https://www.thorlabs.com/thorproduct.cfm?partnumber=RP01). That last fitting to attach (temporarily, pre- or post-flight) the upper adjustable angle mount to the payload landing gear has been started and will be completed here in the next couple weeks.

We're currently revising the draft initial contractual agreement from our colleagues at Globalstar Canada regarding 2 initial SPOT Trace devices (and their service plans) for the educational side-project for the upcoming NATO SPS application, in which classrooms in elementary and high schools could launch company-donated SPOT Traces using party balloons (or a more environmentally-friendly version thereof), and track them to learn more about winds at different levels in Earth's atmosphere.

Houman will send Cordell and/or us updated sections of his master's thesis soon -- that information will be extremely useful to us going forward. Also, Susana and Nathan, it would be very helpful for us all to get the JHU students' final writeup when you have a chance.

Next grant application will be a NATO "Science for Peace and Security" application, together with Australian colleague partners.

Our next telecon is in 30 minutes(!) from now (see below for Skype instructions).

Cheers, talk in a half hour! -- thanks all!


-- jalbert - 2019-06-20

Title Telecon tomorrow (Thursday) @ 5 pm Eastern time
Forum ForumGeneral
Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng OSIOptoelectronicsUV-015withPrecisionPDAmpBoard1kGainAnd780nmLaserDiodeSource.png r1 manage 43.6 K 2019-06-19 - 23:41 JustinAlbert Plot from Andrew Macdonald's photodiode comparison test on 14 Jun 2019. This plot is of an OSI Optoelectronics UV-015 and does not show good linearity (with a 780 nm laser diode source).
PNGpng ThorlabsFDS100withPrecisionPDAmpBoard10kGainAnd780nmLaserDiodeSource.png r1 manage 8.3 K 2019-06-19 - 23:34 JustinAlbert Plot from Andrew Macdonald's initial tests (on 6 Jun 2019) of a Thorlabs FDS100 photodiode with his precision photodiode amplifier board. This plot is with 10k gain on the board when using a 780 nm laser diode source.
PNGpng ThorlabsFDS100withPrecisionPDAmpBoard1MGainAnd650nmLaserDiodeSource.png r1 manage 10.0 K 2019-06-19 - 23:33 JustinAlbert Plot from Andrew Macdonald's initial tests (on 6 Jun 2019) of a Thorlabs FDS100 photodiode with his precision photodiode amplifier board. This plot is with 1M gain on the board when using a 650 nm laser diode source.
PNGpng ThorlabsFDS100withPrecisionPDAmpBoard1kGainAnd780nmLaserDiodeSource.png r1 manage 40.4 K 2019-06-19 - 23:40 JustinAlbert Plot from Andrew Macdonald's photodiode comparison test on 14 Jun 2019. This plot is of a Thorlabs FDS100 and shows good linearity (with a 780 nm laser diode source).
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Topic revision: r3 - 2019-06-20 - JustinAlbert
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