Eclipse Mission Debrief: Loki Lego Launcher 3.0

Our Goals

When we were planning this launch, we had two goals:

1. To capture footage of the moon’s shadow on the earth.

2. To capture and analyze data from our flight computer and solar panel as they pass through the solar eclipse.

Well, for Goal 1, here are some images Dad pulled from the two GoPro cameras:

eclipse totality 2eclipse totality 3eclipse totality 4

Based on these images, we can conclude that we got footage of the moon’s shadow on the earth. Check for goal one!

However, for goal two, when we retrieved our launcher, we found that there was a wire that had come loose on our solar panel. Fortunately, we had wired it in parallel and not serial, so our flight computer data was still good, but we didn’t get any solar panel data. Consequently it is incomplete for goal two.

Therefore, our overall mission results: partially successful.


By the Numbers

Height at highest point (apogee): 29,374 meters (96,371 feet) This wasn’t one of our goals but it was still really cool.

Total flight time: 1:35:42; launch to apogee: 1:10:30; apogee to landing: 25:12. These are our shortest times ever!

Temperature range during flight: -63C to 26C (-81F to 79F). It got pretty cold.

Distance between launch and landing sites:  46.7km (29 miles). It ended up landing in Nebraska!

Distance to hike between car and landing site: 1.5 miles (through ravines and thorny cow pastures) it took an two hours to hike there and back!

The shadow of the moon on the Earth!


Our flight computer data was good.  Our launcher made it up to over 96,000 feet, which is more than triple the height of Mt. Everest!

Our APRS data was incomplete because we had somebody else on the same radio frequency as ours.  We will want to think about this for future balloon launches when there are multiple launches in the area.

Our GPS data was as solid as ever, thanks to our SPOT Trace.  We wouldn’t have been able to find our launcher without the SPOT.

SPOT Trace

Our solar panel data was disappointing.  We didn’t capture any, due to the loose wire. We were unable to measure the impact of the eclipse on the solar power generated, which was a real bummer.

Alt-m vs Temp C
Altitude vs Temperature

Our Altitude vs Temperature graph showed the curve we have expected, where the temperature drops until the reaching the tropopause, and then it goes up until the balloon bursts. It also reached the coldest temperature on any of our launches at -63 degrees C. (-81 degrees F)

Alt-m vs Kmh
Altitude vs Speed

Our Altitude vs Speed graph is very similar to our previous launches, showing the lack of air resistance in the tropopause.

Alt-m vs Pa
Altitude vs Pressure

Our Altitude vs Pressure graph is really strange.  It should be a smooth curve as the pressure approaches zero, but it starts to go really weird at about 11:51am.  It could be a problem with the TP sensor. We may have to try a different sensor for any subsequent launch.

Our GoPro data had some issues too: When we look at the GoPro footage, one camera lasted only 34 minutes and 53 seconds (11:46:53 MT), and the other camera last only 30 minutes 10 seconds.  We had fully charged the batteries in both, but after looking at the data both stopped at our coldest point.  In addition, we had a mechanical failure of some sort, likely due to the impact of an additional spot that we had rigged above the launcher that collided with one of the GoPro’s at 32:09 (11:44:09 MT) into launch.


One of the first lessons we ever learned from the Loki Lego Launcher is to not speculate, and rely on data. We have learned a lot from the data on this launch. Some of it, we don’t understand (the Temperature/Pressure sensor).  Some of it tells us that we didn’t fully check out our wiring (no solar panel data).

Other data confirms that we were able to see the shadow of the moon (visual GoPro data), yay! It also confirms we had a mechanical problem at 32 minutes into launch and our camera batteries don’t work in cold temperatures. However, the good news here is that we were delayed in our launch by almost half an hour. We had originally planned on launching around 10:45am, and we didn’t get the balloon off until 11:12am. Because of that, we were able to get at least a few images of the shadow of the eclipse moving across the earth, hurray!

There are many lessons that we learned, and we are continuing to talk about them as we continue our long drive home (our car ride home always seems to be our mission debrief session).  Stay tuned for more lessons learned, and more thoughts on how awesome it is to be part of a scientific team!





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