For documentation, the below is a brief summary of the ALTAIR flight that Yorke and I did in the early morning hours last Sunday (Aug. 11, 2013), and the recovery of the payload from a tall tree by Todd Anderson, assisted by Yorke (with me observing), the following day (Mon., Aug. 12).
Please do just follow up with anything I happen to miss, or get wrong, Yorke and Todd -- since I'm posting this without checking first to make sure we have the story straight!
Yorke and I began to set up at just before 2 am on Aug. 11 for a launch from Garipay Field in Hanover, NH. Yorke had determined, for a launch at around 4 am, the winds would carry ALTAIR approximately to the location of Robert Frost Lane in Etna, NH (approximately 5 km away from the launch site) if we cut the payload down when it reached 3000 m altitude. The purpose of the flight was to attempt to observe and get image(s) of the payload in flight via the Harvard Meade LX200 portable telescope and SBIG camera (using the green LED beacon rather than the full laser diode and integrating sphere payload, to get experience with getting telescope images without risking the full payload). The telescope+camera and recovery tracking station were set up by Yorke at the Robert Frost Lane location.
The weather was fairly good: clear skies, and predicted and actual winds low enough so that we could at least get up to 3000 m without the payload ending up in deep forests outside the region. There was quite a bit of early morning dew at the launch site.
The setup for the launch went well: we were set up, balloon filled and ready for launch at around 3:20 am. Yorke then proceeded to the Robert Frost Lane location to setup the telescope and recovery tracking station, and I remained at Garipay Field to pull the cord to launch and to man the launch tracking station.
Yorke had set up the telescope and recovery station, and called me by about 4:20 am. He noted that there was some difficulty with the telescope star alignment (needed to track and take images of the payload in flight), and he wanted to try aligning again.
Yorke called again at around 4:35 am, and said that the alignment was likely as good as it would get during the launch window before sunrise (and before sky background would start to increase dramatically) and that we should thus proceed with launch. I thus turned the payload and LED beacon on and, after countdown, launched the balloon and payload at approximately 4:45 am.
The LED beacon was easily visible by eye throughout the entire flight, by both Yorke and myself. Other than the moon, it was the brightest object in the sky throughout essentially all of its flight -- even at apogee it was approximately 1st magnitude. When Yorke performed the cutdown at 3000 m altitude via the recovery station, I could easily see its effects from the launch site a few kilometres both away and below, via the LED beacon and payload shaking, and thus the green light blinking in and out of view. A few cell phone pictures of the green LED beacon during its flight are attached.
Unfortunately, the star alignment of the telescope was not sufficient to get telescope images of the payload in flight. The pre-alignment automatically performed by the Meade LX200 using its level sensors and compass is sufficiently off such that the stars that it then selects for the user's star alignment are actually outside the field of view of the telescope. Yorke and I later (on Wednesday night) diagnosed and (hopefully) solved this issue, but it prevented us from obtaining telescope images of the payload in flight on Sunday.
After Yorke performed the cutdown, he then actively controlled the parafoil in order to attempt to have the payload land as close as possible to the recovery station. Yorke noted that the parafoil did not appear to be responding to commands as much as it should have been. Yorke and I both lost contact with the payload at about 2000 m altitude, and the payload landed approximately 1 km beyond (i.e. east of) the recovery site.
After packing up our respective sites, Yorke and I went driving around, Yorke with an antenna and receiver, to attempt to get a signal and thus GPS location of the payload. At first we were unsuccessful, but after Yorke briefly went home to obtain an improved flight-path prediction of where the payload might be, we then drove to an area that looked like the best possibility, and Yorke fortunately obtained a signal and GPS info. The GPS location of the payload was on land behind the Morton Farm, which is land on the outskirts of Hanover owned by Dartmouth and is the Dartmouth Equestrian Center.
We then proceeded to the Morton Farm to see where the payload had ended up. Behind the Morton Farm there are trails in the woods, one of which took us to approximately 300 m from the GPS location of the payload. We then went off the trail through the woods to the GPS location. The payload was found to be at the GPS location, very high in an oak tree, hanging from the parafoil approximately 60 ft above the ground, with green LED beacon still on. A technical climb, with climbing equipment which we would have to bring later, would be required to retrieve the payload. Location noted, we returned to our vehicles. From our vehicles, Yorke used the antenna to obtain a connection with the payload and turn the LED beacon off, to save the battery from running completely to zero. We then went back to our respective homes to get some rest (at that time it was about 10 am on Sunday morning).
Yorke realized that the dew that collected on the parafoil prior to launch had likely frozen during flight and prevented the parafoil from steering and performing nearly as well as it should have. This definitely seems like the most likely explanation for that.
Todd returned on Sunday evening from a trip to Utah, and is an experienced climber, so he very kindly volunteered to be the tree climber on Monday to retrieve the payload. This is a very hazardous technical climbing task, especially with the payload in a very dangerously high location, so Yorke and I both owe a very great deal to Todd for successfully getting the payload, and more importantly himself, as well as all the ropes, carabiners, and climbing equipment, down from over 60 ft up in a very tall forest tree. Yorke is also an experienced climber, with his own equipment, so he performed the extremely critical tasks of both belaying Todd, and also getting the top-rope started on a branch about 20 feet off the ground. Todd successfully retrieved the payload, and got it and himself down, belayed by Yorke, at about 3:30 pm on Monday afternoon. This was extremely fortunate because early the following morning (Tuesday), starting at about 4 am, heavy rain began, and fell steadily throughout Tuesday.
On Wednesday the skies began to clear, and on Wednesday evening Yorke and I got the telescope out to see if we could understand the alignment. Yorke set it up, and after doing the automatic pre-alignment, he determined the stars which it was then suggesting for the star alignment were both a few degrees outside the two fields of view. Yorke aligned to those stars, and then found that the telescope was then in good alignment, demonstrated by it then being able to accurately and precisely enough (i.e. within no more than a couple arcminutes, which is definitely good enough) being able to find Saturn, Vega, Altair (the star, not the payload), Deneb, etc.
Early the following (Thursday) morning, I had to fly out to go back to the west coast.
Please follow up with what I have missed and got wrong!
thanks, justin
Attachment:
http://projectaltair.org/HyperNews/get/AUX/2013/08/18/20.23-87912-light_CellphoneImage1.JPG
http://projectaltair.org/HyperNews/get/AUX/2013/08/18/20.23-29230-light_CellPhoneImage2.JPG
http://projectaltair.org/HyperNews/get/AUX/2013/08/18/20.23-73793-PayloadInTree.JPG
http://projectaltair.org/HyperNews/get/AUX/2013/08/18/20.23-40301-ToddRecoveredPayload.JPG
