Mission Debrief for Loki Lego Launcher 2.0

Our mission was successful!  We met all of our primary goals:

  1. Reach a height of 27,500 meters (90,200 feet); we made it to 30,880 meters (101, 325 feet).
  2. Complete the launch and descent in less than four hours; our mission length this time was 3 hours and 23 minutes.
  3. See the curvature of the earth on our video footage; see picture above!
  4. Compare data with our first launch and see if we observe the same temperature changes at the same heights; our temperature/altitude graph looks very similar to our last launch.

However, we might have failed on one of our secondary parameters: Parachute not opening.  Our cord between our balloon and parachute was too long and the balloon got twisted around the parachute lines.  When we found the Loki Lego Launcher, it was totally twisted up.

By the Numbers

Height at highest point (apogee): 30,884 meters (101,325 feet)

Total flight time: 3:23:30; launch to apogee: 2:30:30; apogee to landing: 53:00

Temperature range during flight: -55C to 31C (-67F to 87.8F)

Fastest speed during flight: 127 km/h (78.9mph)

Distance between launch and landing sites: 126.8 km (78.9 miles)

Data is Everything

Our APRS Radio Bug that we added as a second tracker to our spacecraft was awesome.  It was so fun to see where it was in real-time, and we were able to be close to our landing site before it actually landed.  (Chasing the spacecraft in the car while it was coming down was super exciting).  It gave us really interesting data that can be analyzed in several ways.

Raw Data from flight computer:   EAGLEB01.LLL2.0 – Copy

PDF charts: Loki Lego Launcher 2.0 Data

APRS track
From APRS.fi, using the latitude and longitude coordinates
LLL2.0 path 1
Using the KML data in Google Maps for a 3D view showing altitude

Plus, our data from our new VI sensor was really interesting.  There is a lot more to analyze, but we think there are going to be lots of other ways to use use this sensor.  We have a lot more data analysis to do over the next few days and weeks.

Our Solar Experiment Hypothesis was Correct

Our solar panel experiment that was on board was based on the hypothesis that as our spacecraft got higher, then there would be less particles in the air that would block the sun’s rays, so the solar panel would produce more current.  Well, according to our data, this may be true!

Alt-m vs M A
Altitude (meters) vs Current (mA)

As can be seen in the chart (that Dad did for us), as the altitude increases, the trend line showing the current data also increases.  The other cool thing is that all those tests that we did while we were trying to figure out this solar experiment were useful, because this data shows that at least our circuitry wiring was correct!


Lessons Learned

Like last time, we talked about what we learned from our launch on the car ride back home from the recovery site.  A few lessons we learned were new, and a few were similar to our first launch.  We referred to our first set of lessons several times during Launch Day.





Launch Day: Play by Play

Online Tracking: APRS or SPOT


2:32pm Successful retrieval of Loki Lego Launcher 2.0!!  We are so excited and happy and thrilled!  We are now going for a cold ice cream, and will take some time to look at the data and the footage.  Thank you so much for coming along with our launch today, we loved having you with us!


2:22pm. It has landed! We’ve parked and are walking through a tall grass field looking for it…

1:41pm It’s on the way down, and it exceeded 100,000 feet!  We’re NE of Ritzville, and are trying to intercept it.  Super giddy group of stratospheric explorers right here.  SPOT signal re-acquired.

12:37pm We’re now back in the car; the hunt is afoot!  Loki Lego Launcher 2.0 just broke through 80,000ft, thus exceeding our previous max height. Go Loki Go!!  The chase is on.

11:31am We’re taking a short pit stop in Moses Lake. Can’t believe how fast the balloon craft is moving.  The APRS data is phenomenal. Our predictor indicated that the balloon will double back, head west, and after bursting, it will turn back east again. Hard to say how high it will go, but it’s fascinating to get this data in real time.  We hope the solar experiment is collecting good data! Back to the chase soon.

10:49am Now the chase begins. Follow along using the links above. The APRS data will also include altitude and temperature.  We’re heading east!

10:42am APRS and SPOT tracking active. Heading in the right direction.

Kimberly celebrates successful launch

10:34am LIFTOFF!!

10:20am Balloon inflated, attaching to parachute and spacecraft now.

9:47am This seems like a nice place to launch a spacecraft.  Launch will likely be closer to 10:30am.

8:47am Launch Directors have (groggily) confirmed weather and wind conditions. We are Go for Launch.  Heading to launch site now.

7:15am – Both Launch Directors still sleeping, hmm… (Dad)
6:13am – Weather at launch time calling for sunny skies around 84F (29C)  with 10-12mph winds from the WSW.  It will warm up to 93F by anticipated recovery time, so it’s going to be a hot day! (Dad)

Online Tracking Links

Click here for Launch Day: Play by Play

We have two online tracking system on Loki Lego Launcher 2.0.  One of the lessons we learned from the first launch was to “have a redundant system.”  We’ll be a lot less anxious now that we have two trackers on board.

APRShttp://aprs.fi/#!call=a%2FKI7CSK-11&timerange=86400&tail=21600 (map refreshes automatically)

SPOT Tracehttp://share.findmespot.com/shared/faces/viewspots.jsp?glId=01LPm5td7Ba6NoyxmiEAaDQvXpGSjeciO


The Automatic Packet Reporting System (APRS) is an amateur radio based system used for real-time communications. We are using the APRS radio transmitter in conjunction with our flight computer to transmit latitude, longitude and altitude to an iGate, or Internet Gate, which allows us to track our spacecraft in near real-time (one minute intervals) on a website like aprs.fi.  The APRS does not work as well as the SPOT Trace on the ground, but it is the only way we can transmit altitude data while in flight. Thanks to Dad, we are officially allowed to use the APRS system because he got an Amateur Radio License (his call sign: KI7CSK).

SPOT Trace

The SPOT Trace is a GPS tracking device that can be used for a variety of applications. It is generally used for tracking things that may be lost or hard to find, like the Loki Lego Launcher. The SPOT uses GPS to transmit its lat/long coordinates to a web page or app approximately once every five minutes and can be attached to practically anything.  One of the drawbacks of the SPOT is that it doesn’t work at high altitudes, as the satellite cannot track it when it is too high. It also does not transmit altitude, which was a problem for us in our first launch. It will be our main source for retrieval of the Loki Lego Launcher because it works best on ground.


Join Us on Launch Day: Saturday July 30

Our testing is complete, we have our new tank of helium, and if the wind and weather cooperate, we are planning on launching Loki Lego Launcher 2.0 on the morning of Saturday July 30th.  Launch location is TBD, probably somewhere in Central Washington again.

We’ll keep our blog updated, and will share a link that should allow anyone to track our spacecraft online in near real-time.  We’d be happy to have you along for the ride! (by Dad)

Our Solar Experiment: Testing, Testing, and More Testing

As mentioned earlier, our second launch is going to have a few differences, including a bigger balloon, a redundant tracking system (APRS), and a different Lego minifigure.

However, the biggest difference is this time, we are going to conduct a solar experiment on board the Loki Lego Launcher.  We are using a solar panel from a solar experiment kit, and we are beta testing a voltage/current sensor from High Altitude Science.

Here is our hypothesis:  as our spacecraft rises higher through the atmosphere, the output produced by the solar panel will increase, as there are fewer particles that will block the sun.  To test this, we will measure the output of the solar panel on the ground by using the voltage/current sensor, and then, when we launch the Loki Lego Launcher 2.0, the flight computer will continue to track the output as it rises.  If our hypothesis is correct, when we analyze our data, we will see that the current increases the higher the spacecraft goes.

Our sensor is also wired to measure the computer’s current consumption. We will have to subtract the amount of current that our computer uses from our total amount of current to get the amount of current that our solar panel absorbed.

On Sunday, we tried to figure out how to wire our solar panel to the voltage/current sensor, and how to position it on our spacecraft.  We tried many different configurations and did test after test after test.  We think we did at least nine different tests that day, trying to figure out the best way to measure an increase in output of the solar panel.  We were doing all the circuitry and wiring ourselves from scratch, which is tricky since we’ve only done some basic stuff at school.

At first we thought we should connect our circuit in parallel, but we wanted to measure voltage, so we connected it in series. But the way the wiring works, connecting in series means that we would need to have the solar panel in complete sunlight for the circuit to be completed and for the entire flight computer to work at all. It wouldn’t track any data. We thought we could use a jumper cable to override the circuit, and it did. A little bit too well.

Current will always follow the path of least resistance and it completely bypassed the solar panel, not getting any energy from it at all. After we figured that out, we went back to connecting the circuit in parallel and measuring current instead of voltage. That way the whole computer would still work without the solar energy, and we could still continue our experiment.

When we tested this configuration and then checked our data, we saw that the current and power increased when we put the solar panels in sunlight, and then decreased when it was in the shade.  Yay, finally!

test data
The highlighted numbers show when we put the solar panel into the sun and the amount of current increased.  Data!

We’ll keep you updated on information. Stay tuned!

Preparing for Loki Lego Launcher 2.0 (again)

Today we are getting ready for Loki Lego Launcher 2.0, which is on track to launch soon. Our project plan has been created and we are reusing our spacecraft just like we said in our earlier post: “Planning for Loki Lego Launcher 2.0“. Our mission goals and changes from Loki Lego Launcher 1 can be viewed there.

2016-07-23 11.10.30

We attached our newly updated flight computer from High Altitude Science, which, in addition to our temperature/pressure sensor, now has a voltage and current sensor. We also added a redundant tracking system called the APRS Radio Bug which relies on radio waves to communicate data to a web page. We will be posting links to track our GPS device and our radio tracking device on launch day.

2016-07-23 11.41.27

Today we also field tested our two tracking devices while driving around town, and have found that both tests were successful. The GPS device can be tracked on our phone with an app and we stopped along the way to track the APRS device with the computer. We’ll post updates on the upcoming launch as the date approaches. Stay tuned!

2016-07-23 13.54.15 (1)