Here are minutes of our telecon Thursday June 9, apologies for the delay -- please just reply with (or let me know) any corrections -- thanks!:
Attendees: Just Yorke and me this time.
Yorke and I tested out the Meade telescope (with its new mainboard) outdoors on the roof of Wilder on the evening of Wednesday June 15. (This was indeed after the last telecon, but I just want to be up-to-date. :) The first two times that Yorke attempted a star alignment, it failed, leading to temporary concerns that evening that there was still a firmware problem, or perhaps some hardware issue with finding magnetic North, etc. However it succeeded excellently on the third try! Thus ... Yorke then tried a fourth time, and there were difficulties in telling which star it was attempting to align to (as its second alignment star), and this fourth alignment failed (i.e., could not then find and point to Jupiter etc properly). So we tried a fifth time ... and again (like the 3rd time) it worked perfectly!
Thus ... Yorke's as well as my present theory is that the first 2 star alignment failures were most likely just because the the telescope (Meade 200LX GPS 12") had not fully obtained a proper GPS ephemeris yet (which like any portable telescope, it requires for star alignment -- the fact that the telescope certainly never said there was a GPS problem might just mean it had properly found 1 or more GPS satellites, but yet not the necessary 4 [or more] for correct ephemeris), and it only found sufficient satellites and correct ephemeris by the time of the third try. The failure on try #4 was perhaps most likely because of mis-guessing which star the telescope was attempting to align to (it can be very difficult to tell when the star is in a fairly bright star field, and especially when there is an even brighter planet nearby -- unfortunately the telescope software never tells one to which star the telescope is trying to align -- one must guess oneself!)
Assuming the above theory is correct, then ... we just need to give the telescope fully enough time to get a proper GPS ephemeris (which can be up to 15 mins or so), and _then_ make sure we correctly figure out to which star it is trying to align (despite the telescope software not telling us). Those can (especially together) both sometimes be tricky issues (as the telescope software is rather silent on them), but are certainly both solvable and do not require new hardware or firmware. However, this theory probably should be verified with at least one or two more telescope tests prior to the next flight (just to make sure we don't get stuck).
Hardware for the pre- and post-flight photometry cross-check device -- the 12" aluminum sphere (a photo of it is attached in a link at the bottom of this message, http://www.sharpeproducts.com/store/aluminum-12-dia-sphere) as well as the white "Avian-B" Lambertian reflective paint for its interior -- is currently back in the machine shop at UVic for machining and painting. This will be a field photometry check device to, in the field immediately before launch, and right after recovery, cross-check photometry information from the ALTAIR gondola (to an accuracy and precision of about 1% or so. Note that photometry checks which will be more precise than that will be done in the lab, most precisely at NRC, and/or NIST -- however we want to have the ability to do quick cross-checks in the field immediately before and after flight.) Some renderings (of the upcoming device) are also attached in the attachment links at the bottom of the message. UVic machinists say that they will have it ready in approximately a month or two.
We also now have the hardware for (a completely separate) survey-tripod-mounted device to cross-check yaw-pitch-roll information from the gondola (e.g., on days before/after flights) -- a photo of this hardware is in a link at the bottom. That hardware 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) and two adjustable angle mounts (http://www.thorlabs.com/thorproduct.cfm?partnumber=AP180). We'll make the fittings to attach the adjustable angle mounts to the tripod, and to the payload, in the next few weeks.
We're currently revising the draft initial contractual agreement from our colleagues at Globalstar Canada, per requirements from the UVic research services office, 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.
I'm working on completing the motorized, propelled version of the dummy payload for initial fight tests with drops from a tethered balloon -- a few photos of initial assembly are attached in the links at the bottom of this message.
Back at UVic, Karun is working with a sample microcontroller board (with Microchip PIC18F87J50 microcontroller) from the UVic electronics shop, to use for testing motor control for an ALTAIR motor and propulsion control microcontroller board we will be designing this term. He has now gotten the pulse width modulation code for it up and running -- video at
https://particle.phys.uvic.ca/~jalbert/MotorAndPropTests/IMG_2136.MOV
and Karun has also solved the problem of simultaneous control of two propulsion motors, and of controlling a servo as well as propulsion motors. He's now working on monitoring the input from the on-chip A/D converters (which will be monitoring temperatures, motor RPM rates, and current flow). We just purchased a second little PIC microcontroller board: http://www.digikey.ca/product-search/en/programmers-development-systems/accessories/2621524?k=PIC18F97J94 with a more advanced version of the PIC18F87J50 -- the PIC18F97J94 -- so that we can test out that new one as well before we make our custom board with it. We also have the beginnings of a little mechanical test rig, the internals and externals of which can be found in the four attached photos, and in the following movie showing the lightweight but strong servo gearbox for rotation of the propulsion support axle:
https://particle.phys.uvic.ca/~jalbert/MotorAndPropTests/IMG_2145.MOV
and now the setup is all together, and just waiting for monitoring sensors (motor RPM, current, temperature) and microcontroller control:
https://particle.phys.uvic.ca/~jalbert/MotorAndPropTests/IMG_2198.MOV
As a backup / cross-check, we are simultaneously trying an Arduino-based control system (which uses an Atmel ATMega 2560 microcontroller). When within ALTAIR, the motor and propulsion control microcontroller board will logic interface with Yorke's main board (in a similar way to how the present cutdown-motor control board interfaces with the main board. Separate propulsion battery will of course be carried.) Screenshot of a propulsion system slow-control and monitoring program which I've been working on is attached.
Regarding simulation of the above, James Hartwick (senior undergrad here at UVic, who has done an enormous amount for ALTAIR, including much of the current projectaltair.org website, light source work, etc) has now written an ALTAIR flight propulsion control and simulation program, which includes GFS (global forecast system) file input, for both forecast and real-time information of winds at all points in Earth's atmosphere. We'll have plots, images, and data from his software coming up very soon. I am developing a visualization interface for this control and simulation program, which will be based on Google Earth, but display the real-time (as well as forecasted) winds within Google Earth in a way that is somewhat similar to this site:
https://earth.nullschool.net
I'm working on a streak-vector display of winds within Google Earth that is reminiscent of the above site, and you can see a first attempt (with a single streak) here:
https://particle.phys.uvic.ca/~jalbert/GoogleEarthWindMovie.mov
UVic undergraduate Tyler Makaro will be helping us with the above as well.
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.
Our next grant application will be a NATO "Science for Peace and Security" application, together with Australian colleague partners.
That's all I remember, please send things that I forgot. Next telecon *tomorrow* (June 23), tentatively at the new time of 6 pm Eastern time (if no objections to that new time).
cheers, thanks very much all! justin
On Thu, 09 Jun 2016 01:24:48 GMT, Justin Albert wrote:
> Hi! > > Telecon tomorrow (June 9) at the usual time: 4:00 pm Eastern (1:00 pm > Pacific, 10:00 am Hawaii, 22.00 European). Discussion items include: > Meade telescope status and tests; flight planning; light sources and > light source modelling; goniometric and pre- and post-flight > calibration; propulsion work; nanosat bus and payload solid models; > computing/website; 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 (4 pm Eastern, 1 pm Pacific). > 4) If there is any trouble, or if you don't get a Skype-call for some reason and would like to join, just send me an e-mail (jalbert@uvic.ca). > > Here's the tentative agenda: > > I) Telescope tests and current status > II) Flight planning > III) Diffused light source, and its modelling, pre- and post-flight calibration, and goniometric calibrations > IV) Propulsion & motor control work > V) Nanosat solid models & Houman's thesis > VI) Computing/website > VII) Grant applications > VIII)AOB > > Talk to you all tomorrow, thanks! > justin
Attachments:
http://projectaltair.org/HyperNews/get/AUX/2016/05/22/18.23-24702-12inAlSphere.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/04/06/16.53-58615-SideView.pdf
http://projectaltair.org/HyperNews/get/AUX/2016/04/06/16.53-48539-TopView.pdf
http://projectaltair.org/HyperNews/get/AUX/2016/05/22/18.23-93827-tch-roll_calibTripod2.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/05/22/18.23-52091-MountedMotorAndESC.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/06/08/18.04-17780-asseminternal3jun16.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/06/08/18.04-71442-assemexternal3jun16.jpg
http://projectaltair.org/HyperNews/get/AUX/2016/05/04/17.45-92797-opulsionMonitoringNew.jpg
