Tuesday, March 25, 2008

Soli Deo Gloria 9 mission over

Other than post-analysis of the Annapolis pass, the mission is over. Even if the balloon is still flying (this particular balloon has a theoretical lifespan of around 21 days), the transmitter should be silent by now. The image at right shows the final trajectory prediction, this time going far beyond the life of the batteries.

Many thanks to all who have contributed to this flight. Please stay tuned for Soli Deo Gloria 10 in the coming days!

Robert KC8UCH

SDG-9 - any signal reports?

We have this from SV1KU:

from wl KM17UX
AT 080324 1430Z QRG 29.498.84 QSA 1
AT 080324 1830Z QRG 29.497.00 QSA 1
AT 080314 1930Z QRG 29.496.87 QSA 1
AT 080325 0830Z QRG 29.497.88 QSA 1/0
Engine of Logger 32. gb de sv1ku.

Other than that, only a couple of "nothing heard" reports. Anyone else logging last night? If so - and you see something of interest - please let us know. Otherwise, we're about to pull the plug on SDG-9, as the batteries should be just about exhausted by now.

Thanks and 73,

Monday, March 24, 2008

SDG-9 final prediction

The image to the right is the latest - and most likely last - HYSPLIT prediction for the SDG-9 flight. The end of the red line (north of Scotland) indicates where the transmitter's battery will likely die, all of this assuming that the balloon is still aloft.

Note the time scale at the bottom of the image - the end of the line is at 1200UTC today, 25 March. Will the balloon be within range for someone to hear it by this time? I simply do not know.

I have written to several amateur operators in Greenland and Iceland but, as yet, have received no replies. Will it be close enough to the UK to be heard? I have no idea - but I encourage amateurs in the UK to listen closely over the next ten hours and see if you can hear anything.

Thanks again to everyone who has taken the time to listen or drop us a line - and please check back for further updates, including details on the balloon design used in this mission.



SDG-9 update

It is now nearly 1800z on the 24th and the possibilities are narrowing - either SDG-9 is down, or it is flying at around 8km.

The latter is entirely possible and fits well with the temperature data that was received by WB2YDS early in the flight. This lower altitude also greatly increases the chance of frost downing the balloon, but it could still be flying. Were it at the design altitude of 9-10km, then it should already be over Spain at this point (extremely unlikely, unless the transmitter has somehow failed).

If it is still flying and at 8km, then it should be over Greenland right now and about 12 hours away from the UK. Keep listening, folks - it isn't over quite yet!

73 and thanks to all for your help,
Robert KC8UCH

Europe still possible - and many thanks to SNOX!

First, although there have been no reports of the beacon in England or other parts of Europe yet, it is still possible that the balloon is flying at a lower than predicted altitude and thus could be delayed by as much as 20 hours over earlier estimates.

One station, M0XAP in Essex, reported hearing an "S" and a "G" in CW whilst monitoring 29.495 on USB at around 11:45 today - this could be nothing or, perhaps, this was the beacon (the "S" might have been part of a number in the telemetry string). England, please keep listening!

If we still have nothing in another day, then we can assume that the balloon probably met a cold, icy end... If the original float was closer to 8km than 9km, then it might have picked up significant frost over northern Canada or even Greenland. This would have forced the balloon to the ground, ending the mission.

I want to reiterate, though, that we simply don't know at this point and it is still entirely likely that the balloon will be heard in Europe. So please, keep monitoring 29.499 (and lower after sunset, possibly down by as much as 3khz).

Many, many thanks to Dan Bowen and the SNOX team for passing along our information to their listening network in Europe!

Sunday, March 23, 2008

SDG-9 European alert

Assuming that SDG-9 is still flying at this time, it is possible that stations in England may be within listening range at any time in the next 24 to 36 hours.

That is, given the ambiguity about the balloon's exact altitude and thus trajectory, it could be within range of England now or it might not arrive for another day or so. Once it is within range of a given station, it will probably be readable for four to six hours at most. So if you have the ability to set up Spectran or some other recording software, now would be the time to do it. A gap of four hours could cause you to miss the balloon entirely.

Assuming that we make it to England, the next passover would be Spain. Please see the image in the previous post for more information on possible trajectories.

NB: After a long night at -45C, the frequency of the transmitter will most likely have been shifted significantly downward (WB2YDS noted a drop from 29.499 to 29.496 Mhz as the payload temperature dropped from -9C to -40C after sunset on the first day of the flight).

If you hear it at all, please drop me a line at rochte@gmail.com!

Thanks and 73,

SDG-9 update and European timeline

So far, I have only heard back from one individual in Newfoundland and, as noted in my previous entry, he did not hear the beacon. It seems we've come up with a twist to the old "tree falls" riddle: "If a beacon flies on a balloon and no one is around to hear it, does it make any sound?"

There are three distinct possibilities as to what has happened to SDG-9:

1. It had pinholes or other defects and subsequently lost gas, causing it to descend.

2. Radiative losses during the night cooled the gas sufficiently to offset the initial superpressure and decrease the balloon's volume, causing it to descend.

3. It is still flying.

The first alternative is certainly possible, but earlier SDG flights have demonstrated that our three-layer film is capable of holding gas under pressure for at least 32 hours (our previous flight record). It could have lost gas due to a mechanical defect, but I doubt it.

The second alternative is what most likely cut many of our earlier flights short. In particular, SDG-6, the 32 hour flight, almost certainly suffered from radiative losses and subsequent contraction of the gas (and loss of lift) when it descended the first night. I believe that we have corrected this problem, however, by almost doubling our initial superpressure compared to our earlier balloons (from 5% to 10%).

The third possibility - that it is still flying - is certainly my fondest hope and it is entirely likely. If so, then, save any possible listeners in Greenland (are there amateur radio ops in Greenland?), the next place where it might be heard is Iceland and, thereafter, Scotland.

Assuming that the balloon reached stable float at 9km, it should pass Iceland between 1800z today and 0000z on the 24th. It should then reach Scotland about four hours later, at 0400z on 24 March.

If stable float was indeed at 10km - which I doubt - then it will be a bit behind that schedule, nearing Iceland at 0400z on the 24th and Scotland several hours later.

The accompanying HYSPLIT projection (click it to see a larger image) shows trajectories for 8, 9 and 10km altitudes to battery exhaustion, about 96 hours after launch. Note that the 8km trajectory still leads to Europe, but quite a bit later. (Note the time scale along the bottom of the image.)

Please, if you can spare any time at all this Easter to monitor 29.499 Mhz for our CW signal, please do so! Without listeners, the balloon could easily fly over continental Europe and no one would even know! Note that the frequency tends to drop a bit after local sunset for the balloon, so keep this in mind when listening.

We gratefully acknowledge the NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT transport and dispersion model and/or READY website (http://www.arl.noaa.gov/ready.html) used in the accompanying trajectory projection.