Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all,

Telecon tomorrow (Apr. 29 in North America, Apr. 30 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 23.00 European, 7 am Eastern Australia). We now have our 4 SHX1 144 MHz transceiver modules returned to us from Radiometrix in England, and Nick Braam in the electronics shop will be soldering them back on the transceiver boards and testing them out first thing next week. Progress also continues to be made on the new ALTAIR form-factor version of the ORCASat transimpedance amp board, and on electrical characteristics of the photodiode readout -- also some more work done on optical simulation. We additionally have recent updates on AIFCOMSS, etc. More discussion items for tomorrow's telecon include: flight/telescope plans and tests; construction and lab tests of the new gondolas/payloads; 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 a progress report 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
VII) AOB

Talk to you all tomorrow, thanks!!!
justin

-- jalbert - 2021-04-28

Hi all,

My apologies for the delay! -- here's an update on recent ALTAIR balloon work, minutes of the last meeting on Apr. 8 (attendees Arnold Gaertner [NRC], Liviu Ivanescu [Sherbrooke], and me), and a reminder of the telecon in 15 minutes(!) from now:

As mentioned in the e-mail sent yesterday, the Radiometrix SHX1 144 MHz transceiver modules are finally (after a year abroad in England) now back with us in Victoria -- here they are:

and they'll be soldered back onto our transceiver boards

by Nick Braam first thing next week. As you may remember, these transceiver boards can either work with an RS-232 connection directly to a computer's serial port -- or (as either in flight on ALTAIR, or in the ALTAIR ground stations) via the UART serial connection through the "expansion header" on the boards. In order to do the latter, one has always had to un-solder the little surface-mount MAX3232 chip that one sees next to the RS-232 connector on the boards in the photo above (also seen in the old schematic for the boards shown here:

). Since we have had to solder and unsolder those little MAX3232 chips from the board a lot over the past 5 years, Nick will be adding (at the same time he solders on the SHX1 modules) a little slider switch to the boards, so we no longer will need to solder and unsolder those MAX3232 chips in order to switch from RS-232 interface to serial UART interface -- we'll just be able to slide that little switch. That will be a very welcome update/fix!

Nick will then also test out the functionality of the boards after the SHX1 modules are soldered back on and the switch is added, and then hand them back over to me.

Regarding the (entirely separate, of course) TIA board, Andrew Macdonald is still working hard on the ALTAIR form-factor version of the ORCASat transimpedance amp boards (his spec sheet here:

) and he should have schematics + Gerber files by next week, and will send them out for fabrication the week after. (The department electronics shop has been moving its lab space, which explains why his schematics + Gerber files have been slower than I thought they would be.)

We now have a 1/1000 voltage divider for our new PDVS2mini calibrated voltage source (https://www.ianjohnston.com/index.php/onlineshop/handheld-precision-digital-voltage-source-2-mini-detail), using one of these precision matched combined resistors: https://www.digikey.ca/en/products/detail/caddock-electronics-inc/1776-C6815/4360753?s=N4IgTCBcDaIIwHYEDYC0BhZAOOBWVAcgCIgC6AvkA and an ultra-low-offset-voltage op-amp: https://www.digikey.ca/en/products/detail/texas-instruments/TLC2652AIP/277463?s=N4IgTCBcDa4JwDYC0BGAHOpBWJA5AIiALoC%2BQA , so that we can reliably and very precisely put 1 uV (or even 500 nV) through our Guildline 1MOhm resistor (when it arrives within the next week or so) to have a very precise 1 pA (and/or even 500 fA) current source for calibrating the TIA boards.

I've begun to look some more at MEEP (https://meep.readthedocs.io/en/latest/) for finite-difference time domain (FDTD) simulation of integrating sphere output, but I haven't yet had time to make any significant progress there -- I'm hoping to do that in the next couple of weeks. It will be interesting to compare that with ray tracing simulations, when I can get a chance to do that!

We also will be doing more connecting up and testing out of our two new 144 MHz Raveon M8S data modem transceivers here in Victoria:

After checking them out with Raveon's Windows-based Radio Manager software, I've started to connect the radios up to Arduino Megas -- in the next few weeks I'm planning to get them talking to one another, and then I'll check out their effective ranges.

Once we get our 144 MHz transceivers settled and back into the ALTAIR gondola, we'll do some outdoor drop testing of the actual gondola. (We've done all the outdoor drop tests I can think of doing with our dummy gondola.)

And we also still need to test out our new DFRobot SEN0177 payload aerosol monitors that we have here:

Engineering students Josh Gage and Evan Moore found that the "wings" that Josh had found in the laser diode light output distributions:

were due to how the diode was mounted in the heat sink. When the diode is mounted properly and carefully, the wings go away.

We also have our 10 Hamamatsu S12698-01 photodiodes and 3 Thorlabs FDS100-NOCAN photodiodes (those Thorlabs ones have their windows removed) here in Victoria:

I've given them to Evan to try out -- he's taking a few weeks to ramp up, and will produce some linearity, etc., plots from them soon.

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 15 minutes from now -- see below for Skype instructions.

Cheers, talk in 15 mins (!) from now -- thanks all!

justin

-- jalbert - 2021-05-04