Telecon tomorrow (Thursday) @ 5 pm Eastern time

Hi all!

Telecon tomorrow (Feb. 2 in North America, Feb. 3 in Australia) at the regular time: 5 pm Eastern (2 pm Pacific, 11 am Hawaii, 23.00 European, 9 am Eastern Australia). We have an initial image, taken on DECam at the Blanco-4m, of the ORCASat light source trail!!! -- a screenshot is attached! However, all is not perfect (yet?) in ORCASat-ville: the attitude determination and control system (ADCS) onboard ORCASat is still having trouble both determining (even to a precision of ~30deg -- the nominal precision of attitude detemination should be around 1deg) ORCASat's attitude, and also controlling the attitude so that the sphere output port is pointed either at nadir, or directly at the observing telescope itself, during observations (or at least pointed somewhere somewhat reasonably nearby -- even just anywhere within ~60deg). Some more on this issue will be in tomorrow's report.

And ALTAIR-wise, we have quite a bit of continued progress on 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 on the population and testing of the new ALTAIR photodiode 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 - 2023-02-01

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. 19 (attendees Arnold Gaertner [NRC], Liviu Ivanescu [Sherbrooke] and me), and a reminder of the telecon in 10 mins (!) from now :

As promised in the telecon announcement yesterday, a quick update on ORCASat: Using DECam on Blanco, we made 3 observation attempts of ORCASat overpasses there on Jan. 29 at approximately 05:31 UTC, on Jan. 31 at exactly 05:23 UTC, and on Feb. 1 at approximately 04:31 UTC -- the middle (Jan. 31) one of which was successful (in that we observed the trail on the image from the ORCASat 660 nm light source, as seen in the screenshot sent yesterday:

), but the other two of which (Jan. 29 and Feb. 1) were not (i.e., no ORCASat trail observed on those images). The reason for the two unsuccessful observation attempts -- and probably also the reason for the dimness of the ORCASat trail on the one successful one -- is that ORCASat's pointing, i.e. its attitude control, is still not functioning well. I will be discussing this, and how to (hopefully!!!) fix it, with our engineers / project managers Alex Doknjas and Levente Buzas, as well as Afzal Suleman, in 2 hours from now. Very hopefully we'll be able to successfully solve those ORCASat pointing issues, and soon!!! (And also if possible -- i.e. if we get to the point where we feel we know [a postiori] what ORCASat's pointing was during the successful Jan. 31 observation to a precision of around 20 degrees or better -- then we will analyze the photometry of that Jan. 31 ORCASat trail.)

Over to ALTAIR now: Now that Andrew Macdonald has finished populating the half of an ORCASat photodiode readout board (for the purpose of performance comparison with the two ALTAIR photodiode readout boards), he has begun populating the third and final ALTAIR photodiode readout board. (And additionally, Andrew has continued to make more progress with writing/debugging Arduino code to get the data from the ADCs.) After Andrew has finished populating that third ALTAIR board, 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.

Engineering student Hussain al-Hassani is continuing to work with the P3 solar panels and new electronics for daytime in-flight battery charging with them. We encountered a big oscillation from the step-down converter (https://www.digikey.ca/en/products/detail/flex-power-modules/PKU4116CSI/10287647) that he/we are trying to solve with a capacitive-inductive filter (before we can direct the output of the step-down converter into the battery charger IC -- https://www.mouser.ca/datasheet/2/609/LTC4162_L-2956032.pdf).

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 10 minutes from now! -- see below for Skype instructions.

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

justin

-- Justin Albert - 2023-02-02