Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all!

Telecon tomorrow (Jan. 19 in North America, Jan. 20 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 22.00 European, 9 am Eastern Australia). I'll send the update on ORCASat within the progress report tomorrow (I'm actually presently waiting on an update on ORCASat nadir-pointing status from project managers Alex Doknjas and Levente Buzas myself!) -- but there are also a lot of ALTAIR updates too!: we now have the very-beginnings of a system for in-flight daytime battery charging using the three 30W P3solar solar panels that will go on the very top of the balloon, and new electrical engineering student Hussain al-Hassani will be testing that out on Friday and designing a little PC board for it; and also Andrew Macdonald has now completed the population of new readout boards! 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; ALTAIR gondola and payload solid models; computing / website / TWiki forums and e-mails; grant applications; and recap of schedules.

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

-- Justin Albert - 2023-01-19

Hi all!

My apologies for the delay! -- here's the update on recent ALTAIR balloon work, minutes of the telecon 2 weeks ago on Jan. 5 (attendees Liviu Ivanescu [Sherbrooke] and me -- Arnold Gaertner [NRC] was away but should be back today! :), and a reminder of the telecon in one hour and 20 mins (~80 mins) from now :

As promised in the telecon announcement yesterday, a quick update on ORCASat: project managers Alex Doknjas and Levente Buzas have been working for the past week on an issue involving the ADCS (attitude determination and control system) usage of the onboard magnetometer data. Alex and Levente successfully detumbled ORCASat and then got ORCASat into a Y-Thomson spin without usage of the magnetometer -- in fact the magnetometer was only deployed (i.e. the little arm with the magnetometer on the end of it was only extended) just about 10 days ago. (Detumbling was on Jan. 1 and transition to a Y-Thomson spin occurred over Jan. 1 - 4.) The magnetometer data is and has been looking perfectly good since it was deployed ~10 days ago, but the ADCS (which is the one complex purchased component aboard ORCASat -- it was manufactured by CubeSpace [a company based in South Africa]) does not presently appear to be using the magnetometer information correctly. Alex and Leve are working with CubeSpace to solve this -- it will hopefully be solved in the next few days, so that ORCASat can get into nadir-pointing mode.

We do, however, now have a decent TLE for ORCASat's orbit -- it is:

1 55126U 98067UT 23019.28365134 .00061239 00000+0 97523-3 0 9995
2 55126 51.6427 345.8790 0002398 335.2724 24.8151 15.52672048 3318

(per https://db.satnogs.org/satellite/LENB-9037-9456-1559-8946#data ). This is rather different than the orbit I had been expecting based on the ISS orbit TLE from Nov. 30 (that has been available since that date on https://evdc.esa.int/orbit/ ) and the relatively small ejection velocity of ~1.7 m/s of ORCASat from its deployment -- I had been expecting ORCASat to be much closer to the ISS (and also the ISS to be in an orbit that is closer to the one that it was in on Nov. 30) than the above new TLE indicates! In particular, we were expecting the first 3 observable nighttime overpasses of the Blanco telescope in Chile to be on:

> 1) Jan. 27 at approximately 3:46 am local time in Chile
> 2) Jan. 28 at approximately 2:58 am local time in Chile
> 3) Jan. 31 at approximately 2:11 am local time in Chile

but now it appears that they will instead be at:

> 1') Jan. 28 at approximately 3:20 am local time in Chile
> 2') Jan. 29 at approximately 2:28 am local time in Chile
> 3') Jan. 31 at approximately 2:20 am local time in Chile

Note that overpass 1') is "fairly similar" to old estimate in 2); and overpass 3') is "fairly similar" to 3) .... However, overpass 1) has gone away (there is no good overpass on Jan. 27 now!) and been effectively replaced by an overpass on Jan. 29 (which I don't know if we'll be able to observe at Blanco -- it will of course depend on the observing schedule then). I just got the above TLE this morning, so Karun and I will need to interface this afternoon with CTIO to see if the above changes can hopefully be accommodated...!!!

Anyway ... over to ALTAIR now: Andrew Macdonald has continued to make excellent progress on the half of an ORCASat photodiode readout board for the purpose of performance comparison with the two ALTAIR photodiode readout boards: he's completed that population, and here's the latest photo from Andrew:

as compared with the photo of the board from 2 weeks ago:

And additionally, Andrew has made more progress with writing/debugging Arduino code to get the data from the ADCs. Thus, after the third ALTAIR board is also populated, we'll be able to re-make Adithi Balaji's nice plots of transimpedance amplifier linearity:

in order to fix the problems with the reverse-bias plots in the above, as well as make new versions of the plots for the newer boards.

New electrical engineering student Hussain al-Hassani is currently working with the following DC step-down converter that we just received from Digi-Key!:

https://www.digikey.ca/en/products/detail/flex-power-modules/PKU4116CSI/10287647

to solder some temporary leads on each of its 6 contacts, so that tomorrow (Friday) we can test it with our 3 P3Solar 30 watt solar panels in series:

https://p3solar.com/portfolio/p3-30w-portable-solar-charger-clone/

to see if it steps the ~75 V from our 3 solar panels in series down to ~32V that would be suitable for input into a battery charger IC such as:

https://www.mouser.ca/datasheet/2/609/LTC4162_L-2956032.pdf

at a decent power efficiency (around 93%, per the specs of the step-down converter). Hopefully we'll have some decent sun outdoors here tomorrow so that we can do that outdoor solar panel circuit test.

Over these next two weeks, I'll finally get a chance to make additional updates to the AIFCOMSS code that I committed approximately three months ago ( https://github.com/ProjectALTAIR/AIFCOMSSwithCUPredictorTest ) in order to start adding station-keeping algorithms to AIFCOMSS. (Teaching plus organizing local events for the ORCASat launch, etc, had been swamping me!!! But I should finally have a respite which allows me to get this task done by late next week.)

The two 144 MHz Raveon M8S data modem transceivers are still here in my office (together with the LiPoly batteries that power them). I got a chance to do some initial tests of Colton Broughton's most recent code updates for them, which can be found in:

https://particle.phys.uvic.ca/~jalbert/ALTAIR_M8S_Colton8dec21/

(as compared with his older code within https://particle.phys.uvic.ca/~jalbert/ALTAIR_M8S_Colton17nov21/ ), and there were some issues -- I'll also be working on those over the next weeks.

Regarding the latest news on our four Radiometrix SHX1 144 MHz transceiver modules that were returned to us from Radiometrix (following their firmware update to fix the BUSY output):

and the problems that Colton found with them (i.e., that of the 12 radio TX to radio RX permutations between those 4 boards, only 3 of the 12 permutations work, 3 of the other permutations give spotty connections -- e.g. only around 1 out of every 5 characters gets successfully transmitted -- as if one is transmitting and the other is receiving on neighbouring channels, but not the same channel..., and the remaining 6 permutations do not successfully receive any transmitted characters) -- we sent an e-mail to Radiometrix to ask about this about a year ago. They then sent back an e-mail a week later asking for more information, and Colton replied to them the next day providing the info (just a query about what logic voltages we were using -- we've being using 5V TTL from our Arduino Megas). Radiometrix has not replied to us since that e-mail reply sent to them about a year ago, and thus I pinged them 11 months ago to follow up, and again 10 months ago -- and Radiometrix hasn't replied to those yet either. I will be pinging Radiometrix on this yet again next week.

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:

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 one hour and 20 minutes from now! -- see below for Skype instructions.

Cheers, talk in 80 mins (!) from now -- thanks all!

justin

-- Justin Albert - 2023-01-19