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Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all,

Last ALTAIR telecon of 2020 tomorrow (Dec. 17 in North America, Dec. 18 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, noon Hawaii, 23.00 European, 9 am Eastern Australia)! Evan is still very hard at work on testing our new boards (i.e., the transimpedance amps and motherboards). I've done a little bit more work on Monte Carlo simulation, and also some calculations of AB magnitudes of blackbody sources and their reflections (which I'll send around tomorrow). 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

Talk to you all tomorrow, thanks!!!

-- jalbert - 2020-12-17

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 20 minutes(!) from now:

Our electrical engineer Evan Moore is still working very hard on testing the new updated transimpedance amplifier (TIA) boards that we have from the fabricator (OSH Park). The Keithley 2450 source-measure unit that we ordered, which will aid us in the precision testing of the boards, hasn't arrived quite yet (it is supposed to arrive at the end of the month); however there is a lot that Evan can test, and presently is testing, before that arrives. He 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 measuring the linearity of the photocurrent amplification etc. (I've asked Evan to send me a few cell phone photos of the boards, and of his present testing setup, but he hasn't sent me those quite yet. I'll post them when he does.) We also intend to get a 1 MOhm calibrated resistor (also to aid in testing and cross-checks) right at the beginning of the new year.

Entirely separately, I wrote up the following brief document:

in regard to some questions I got -- which are not directly related to ALTAIR (nor to ORCASat), but nevertheless may be of interest to both of those -- from an engineer at Thales-Alenia in France in regard to the expected apparent magnitudes of solar reflections from satellites. So, I collected some formulae that are relevant for determining AB magnitudes of blackbody sources (including, of course, the Sun) and their reflections, and put them in the above document. This may be of interest for determining the effective apparent magnitude of solar reflections, if/when present, off of the ALTAIR balloon and payload (and/or reflections off the ORCASat surface, or of the surface of other satellites, or balloons).

I've also been starting to do a little more work on ray tracing Monte Carlo simulation, and have started using the ROBAST (https://robast.github.io) open source ray tracing package. So far, I've just been doing some of the examples in the documentation, to start out, after having locally installed it -- and it appears to work very well for me so far. Here are some screenshots from my laptop of those examples:

My next tasks for that are 1) to make a hole (i.e., an output port!) in the sphere shown in the last of the 3 screenshots above; then 2) to turn its interior surface from a mirror into a Lambertian surface; and then 3) to generate a lot more rays.

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. Our department electrical engineer Nick Braam has sent them (this Monday, Dec. 14) an e-mail to check up on when they will (finally) be sending the firmware-updated SHX1 modules back to us. 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 20 minutes (!) from now -- see below for Skype instructions.

Cheers, talk in 20 mins (!) from now -- thanks all!


-- jalbert - 2020-12-17

Title Telecon tomorrow (Thursday) @ 5 pm Eastern time
Forum ForumGeneral
Topic attachments
I Attachment History Action Size Date Who Comment
PDFpdf ABMagnitudesOfBlackbodiesAndOfTheirReflections_v17dec20.pdf r1 manage 442.7 K 2020-12-17 - 22:03 JustinAlbert brief document on calculation of AB magnitudes of blackbody sources and their reflections
PNGpng ROBASTSphereWithRayScreenshot15Dec20.png r1 manage 567.6 K 2020-12-17 - 05:52 JustinAlbert screenshot of a (getting a bit closer to being more relevant for our purposes) ROBAST ray tracing example of a ray within a sphere with a mirror interior surface
PNGpng ROBAST_HESSExample1stScreenshot15Dec20.png r1 manage 731.1 K 2020-12-17 - 05:49 JustinAlbert screenshot 1 of a ROBAST ray tracing example (of the HESS telescope)
PNGpng ROBAST_HESSExample2ndScreenshot15Dec20.png r1 manage 755.9 K 2020-12-17 - 05:50 JustinAlbert screenshot 2 of a ROBAST ray tracing example (of the HESS telescope)
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Topic revision: r2 - 2020-12-17 - JustinAlbert
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