Here are minutes of our meeting on Thursday, as well as a brief report on our flight on Wednesday (July 29) morning -- please just reply with (or let me know) any corrections -- thanks:
Attendees: Yorke Brown (Dartmouth) and Karun Thanjavur (UVic)
We'll start with the brief report on our flight and observations on the morning of July 29 (which we of course discussed at the telecon):
In the few days prior to this ALTAIR 14 flight, Yorke's HABHub-based flight prediction predicted a flight path from Thetford Academy in Vermont to just east of our very-commonly-used Robert Frost Lane science site with a 4:30 am (dawn) launch on July 29 (and a cutdown at approximately 4000 m), and thus we planned for this flight trajectory. Thus students Galen Brown (Dartmouth) and Asher Lantz (Middlebury), technician Bob Eccher, and Yorke and I assembled at the Wilder building at Dartmouth at 2:30 am on July 29 per plan. After conferring about the weather status at that point (the weather was iffy, with some low clouds at around 5000 ft -- although neither the clouds, nor the weather in general, turned out to be a significant problem in the end), we decided to go ahead with the flight, and packed the two BL150 helium tanks and launch boxes into Bob's truck, the ALTAIR gondola into my vehicle, and the science station and recovery equipment into Yorke's vehicle. Bob and I, together with Galen, headed to the launch site at Thetford Academy, and Yorke and Asher headed to the science/recovery site at Robert Frost Ln; we all ended up leaving the Wilder building at Dartmouth at 3:30 am. Bob, Galen, and I arrived at the Thetford Academy launch site just before 4 am and immediately started setting up. Filling the balloon, the new rigging procedure (with the "hat" on the gondola), setting up the launch site tracking computer and SPOT tracker, and properly folding the parafoil all take time; by the time we were nearing completion, it was 5 am and dawn was breaking. (An hour is just not enough time to reliably fully set up the launch site without rushing; two hours would be much more appropriate. Also, the current version of the launch procedures involves a lot of turning off and on of the gondola; at the last one of these, we lost telemetry connection with the tracking computer, and the resulting need to try cycling power to the laptop, etc, cost us a good 5 minutes, while dawn was breaking). We were able to launch at 5:03 am. Very fortunately, the science station at Robert Frost Lane was able to establish telemetry with ALTAIR just about a minute after launch, and the telemetry at the launch site also remained active; we all breathed a sigh of relief (given last year's fateful ALTAIR 13 flight) when that occurred. The flight itself was brief, as predicted -- just about a half hour. Yorke reports that telescope tracking worked well and images (naturally with a lot of sky background at that time) were recorded. Yorke commanded the payload cutdown at an altitude of about 4300 m. The payload initially descended according to plan; Yorke thought at first that the parafoil turn commands were not working, but Yorke's later analysis of the flight GPS telemetry indicates that the descent, and the commanded parafoil turns, worked exactly as they should have. However ... when the gondola had descended to an altitude of approximately 2000 m, the main board determined that descent had completed, and thus initiated the RF beacon, and removed the ability to command parafoil turns, at an altitude of ~2000 m, rather than when the payload actually finished its descent. Fortunately, this did not cause disaster, as the payload landed as usual in a tall tree, but very fortunately missed (landed about 300 m east of) Goose Pond in Canaan, NH. Following descent, Galen and I drove to meet Yorke and Asher (Bob Eccher had left for work while we were mid-flight) at the Robert Frost Lane location, and we began the search for the payload. Both the beacon and the SPOT locator worked well, and provided us identical information indicating that the gondola landed in the woods about 300 m east of Goose Pond. Yorke, Galen, and I drove over there to search, and Yorke spotted ALTAIR about 20 m up in a tall tree. The tree looked too unstable to climb, ALTAIR was out on a far limb, and anyway we did not bring sufficient equipment to climb, so we returned to our cars and went home to rest.
To recover ALTAIR, Yorke and I determined that the best course of action was for me to purchase a "line launcher": http://www.wesspur.com/throw-line/big-shot.html, as well as some launch line and a launch weight: http://www.wesspur.com/throw-line/throw-line-kits.html, and we would use those to shake down and recover ALTAIR. I purchased them on Thursday July 30 with free FedEx shipping, however their free FedEx Home Delivery service corresponded to FedEx Ground shipping, and the company is in Washington state, so it took a week to arrive. When the line launcher arrived mid-day on Thursday Aug. 6, Apurv (MITACS Globalink student who is now here working with us), Yorke, and I went to retrieve it, and within a couple of hours we (mainly Yorke) managed to get it out of the tree. The parafoil is, not unexpectedly, ripped due to the lengthy encounter with the tree, but otherwise ALTAIR looks on a first glance to be fairly unscathed. Diagnostics will be done on the payload this coming week.
The telescope images that Yorke took of the light source mid-flight were very unfortunately entirely saturated due to daylight, so are not scientifically useful. We most definitely need to start earlier (and set up quicker, but most definitely start at very least an hour and a half earlier) at night when we do future flights. So very fortunately no losses from this flight, and a lot of very important operational lessons learned, but very unfortunately no scientific gains.
Thus, some of the primary operational lessons learned (so far) from this flight -- in order of importance:
1) Must start earlier: must assemble at staging area no later than 1 am, and must leave for the launch and science sites no later than 2 am -- otherwise we will end up launching after dawn breaks and getting no good telescope images like we did this time. 2) Science site should definitely observe stellar standards prior to launch. 3) Must figure out why the main board determined that descent had completed, and thus initiated the RF beacon, and removed the ability to command parafoil turns, at an altitude of ~2000 m, rather than when the payload actually finished its descent. 4) Science site must check the functionality of the SPOT tracking device, via the web on a capable cell phone, prior to launch. 5) We should mount at least two, not just one, onboard video cameras, with one of the cameras observing upwards to view parafoil deployment.
In terms of planning for upcoming flights, we need to either get a new parafoil ASAP, and/or find a way of mending the tears in the parafoil we have and have used, or temporarily use the standard parachute that we also have (and, thus, we would not steer on descent on the next flight). We also now need to run checks on the payload to ensure its continued functionality, and also answer the question in lesson 3 above. There is some faint hope that this could be done before both Apurv and I leave back for Victoria on Aug. 17 and 18, but that would mean a lot of work from Yorke as well as us this coming week. I am hopeful that we will be up for that, as the weather is good and there is no reason we couldn't get science images with a standard parachute descent.
Cordell has mentioned that Houman will send the latest design for the baffle and LED mounting, and his master's thesis itself, as soon as he gets a chance. Houman, sending that would be very helpful to us.
Also, Susana and Nathan, it would be very helpful for us to get the JHU students' final writeup. Thus we need:
1) From Houman: Your most recent design for the baffle and LED mounting, and your master's thesis itself. 2) From Nathan and/or Susana: Your JHU students' final writeup (from the end of this past semester).
Thanks very much to Houman, Nathan, and Susana in advance!
Apurv has made a very great deal of progress in testing motor and propeller setups for future gondola propulsion here, new movies of which you can see at:
https://particle.phys.uvic.ca/~jalbert/MotorAndPropTests/IMG_2101.MOV and https://particle.phys.uvic.ca/~jalbert/MotorAndPropTests/VID-20150803-WA0020.mp4
and images of the new thrust testing setup that he and Yorke made, as well as the old rattly one that I made, are in the attachment links at the bottom of this message. We will now work on making, and testing the thrust of, a two-counter-rotating-propellers-and-motors setup, on electronics for monitoring the rotation speed of the propellers as well as the current draw of the motors, and on control electronics and firmware.
That's all I remember, please send things that I forgot. Next telecon this coming week, on Thursday, Aug. 13 at 1:30 pm Eastern time.
cheers, thanks all! justin
On Thu, 30 Jul 2015 01:51:35 GMT, Justin Albert wrote:
> Hi! > > Telecon tomorrow (July 30) -- and we can report on our basically > successful flight today, with launch just after 5 am this morning, and > telescope imagery obtained by Yorke (which will be posted within the > next few days) with assistance from student Asher Lantz -- at our usual > time: 1:30 pm Eastern (10:30 am Pacific, 19.30 European). Discussion > items include: today's (July 29) flight, flight planning, calibration > and observation tests, light sources and light source modelling, > goniometric and pre- and post-flight calibration, communications tests, > new nanosat bus and payload solid models, computing/website, grant > applications, and recap of schedules. A reminder of the CSA project > timeline is attached. Yorke is driving to New York tomorrow for a > weekend family reunion so it's unlikely that he'll be able to join, so > it may be a short meeting tomorrow sadly with just me to report on this > morning's adventures. > > 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 (1:30 pm Eastern, 10:30 am Pacific). > 4) If there is any trouble, or if you don't get a call for some reason and would like to join, just send me an e-mail (jalbert@uvic.ca). > > Here's the tentative agenda: > > I) Flight plans > II) Recent calibration and observation tests > III) Diffused light source and its modelling, pre- and post-flight calibration, and goniometric calibrations > IV) Nanosat solid models, and Houman's thesis > V) Computing/website > VI) Grant applications > VII) AOB > > Talk to you all tomorrow, thanks! > justin >
Attachments: http://projectaltair.org/HyperNews/get/AUX/2015/08/08/20.01-64254-ndPropTestingSetupOld.png http://projectaltair.org/HyperNews/get/AUX/2015/08/08/20.01-55788-ndPropTestingSetupNew.jpg
