Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all,

Telecon tomorrow (Dec. 3 in North America, Dec. 4 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, noon Hawaii, 23.00 European, 9 am Eastern Australia). Evan is presently populating and testing our new boards (i.e., the transimpedance amps and motherboards). I've started doing a little bit of work on Monte Carlo simulation, and we've ordered a Keithley 2450 and are consiering getting a secondard air standard resistor or two as metrological standards for electronics testing. We additionally have recent updates on AIFCOMSS, and on the 144 MHz transceivers (Raveon and Radiometrix). 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 - 2020-12-04

Hi all,

My apologies for the delay! -- here's an update on recent ALTAIR balloon work, minutes of the meeting three weeks ago (attendees Arnold Gaertner [NRC], Liviu Ivanescu [Sherbrooke], and me), and a reminder of the telecon in 10 minutes(!!!) from now:

Our electrical engineer Evan Moore is presently populating and testing the new updated transimpedance amplifier (TIA) boards that we have from the fabricator (OSH Park). As a reminder, the schematic is here:

and here are some of Evan's new renderings of the board mounted together with the sphere (when within the structure of the ORCASat cubesat):

Evan is testing carefully for any current leakage etc -- his carefully-designed guard trace and guard plane around and below the photodiode anode signal trace should definitely prevent that! -- and also measure linearity of the photocurrent amplification etc. In order to make upcoming testing of small current signals easier, we have ordered a Keithley 2450 source-measure unit (https://www.tek.com/keithley-source-measure-units/keithley-smu-2400-series-sourcemeter). That will arrive here around the end of this month (the supplier -- Test Equity in Moorpark CA -- will have more back in stock to send out at that point).

That Keithley 2450 should arrive here reasonably well-calibrated, since it will be new -- but in order to assist in our making calibrated measurements of small currents, and for cross-comparisons of such measurements, I've been thinking of also getting a calibrated resistor or two from Guildline:

http://www.guildline.com/new-products/released/9333-precision-secondary-air-resistance-standards

or Measurements International:

https://mintl.com/products/9331-series/

However, those metrological resistors (even though they are the lowest-cost, and some of the least precise, that Measurements International and Guildline sell!) are very expensive (~ $1500 per resistor), so maybe instead just getting a few plain high-precision 0.01% resistors, e.g.:

10kohm:
https://www.digikey.ca/en/products/detail/vishay-foil-resistors-division-of-vishay-precision-group/Y070610K0000T9L/2609885

100kohm:
https://www.digikey.ca/en/products/detail/caddock-electronics-inc/USF340-100K-0-01-5PPM/2138997
or
https://www.digikey.ca/en/products/detail/vishay-dale/MR106100K00TAE66/957484
or
https://www.digikey.ca/en/products/detail/riedon/101-100KX/4832933

1Mohm:
https://www.digikey.ca/en/products/detail/caddock-electronics-inc/USF340-1-00M-0-01-5PPM/2138998

10Mohm:
https://www.digikey.ca/en/products/detail/caddock-electronics-inc/USF340-10-0M-0-01-5PPM/2138999

via Digikey or Mouser might be nearly as good (since such resistors have nearly as good specs as the Guideline or Mintl encased metrological ones, and are only around $10 - $30 instead of around $1500! -- about 50x cheaper).

I've also been starting to do a little bit of work on Monte Carlo simulation, and have some simple ray tracing toy Monte Carlo plots that can be seen here:

which I'll discuss briefly in the telecon.

Radiometrix still has our four SHX1-144 transceiver modules (they arrived there on Apr. 6) and is doing their firmware update that solves the BUSY output issue. They'll then test them out and send them back to us. Due to the COVID-19 situation in the UK, they've been taking a long time; the UK is enduring its second wave of COVID, and the country is still under a lot of restrictions as a result. In the meantime, we've also been 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 those 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 10 minutes (!!!) from now -- see below for Skype instructions.

Cheers, talk in 10 mins (!) from now -- thanks all!

justin

-- jalbert - 2020-12-04