Report about day 4 (presentations of the mission results)

Today all the teams had held a 8 minute long presentation about their mission results. We might also upload our presentation on our YouTube channel.

At the moment we all are waiting for the jury verdict. Thus additional information will follow soon.

Report about day 3 (launch day)

Yesterday we launched the CanSats. The weather conditions were less than optimal. It rained the whole day and it was foggy. This was a problem for all the teams, especially for us because our secondary mission is based on pictures taken by the CanSat during its fall.
But this was not our only problem. At launch, we suddenly lost connection to the BMP280, which task it is to measure air pressure and temperature. Coincidentally, we took the following picture.

We assume that the BMP was positioned directly over the marked screw, which we think hit the BMP quite hard at the launch of the rocket. Thus we could not create a complete temperature and a pressure profile nor calculate the derived values for barometric height and descent speed.

This is quite a problem for us, because our CanSat is programmed to only start taking pictures at a certain height, which was not possible.

Fortunatly, we wanted to isolate the components from each other in case one of them fails and thus we added a button to our ground station to trigger the flight mode manually.

The next problem we faced was that we could not find our CanSat even after two long periods of searching despite having GPS data. Thus we could not recover all the data (in-flight taken pictures and the complete logs).

One of our lessons learned from this is that it would be worthwhile to have a redundant set of sensors, which work independently, to measure the data required for the primary mission. This would come at comparably low costs and effort, but would secure us against such misshapen. Further, we could have provided some sort of mechanical shield or cage for the sensor that would have protected it.

In conclusion the launch was very disappointing.

Report about day 1 and 2

Yesterday evening we met the other teams from all over Europe for the first time during the opening ceremony and the social dinner. Afterwards, we finished our work on the parachute and created the 5 minute-presentation for today.

Today we drove at 8:00 am to the airfield Rotenburg Wümme for the technical inspection of the CanSats, the drop test, and the short presentation.

view of the runway

After we held our presentation, we passed the technical inspection and the drop test. At the drop test our CanSat was dropped off by a drone at a height of 50 meter. It was required that the parachute would not slow down the fall too much. A maximum fall time of 7 seconds was allowed for. Our drop took 6 seconds, so we have permission to fly tomorrow! Our CanSat also survived the drop-test unscathed, only the batteries moved slightly.

The certificate of the technical inspection and the drop-test

RIP CanSat No. 2

Today we made a routine inspection and found a hardware fault at the Pi 3 from our second CanSat. We assume that a part of a chip of the camera interface was broken off.

here we circled the broken element

So we will only be able to use our first CanSat at the competition. Now we plan to use the second CanSat as a dummy during the competition. 

A dummy for our CanSat

Today we finished our dummy required for the drop test. This test is part of the inspection that our CanSat has to go through on the 2 launch day.

here the sideview

The drop test is made to check whether our CanSats meet the specified sink rate. For this test it is important that the dimensions and the weight, as well as the parachute fastening, are exactly the same.
Therefore the satellite will be brought to a height of 50 m by a drone and from there it will be dropped.
Our sink rate should be around 8 m/s (for the competition is a sink rate between 8 m/s  and 11 m/s recommend) sothat we should take good pictures.

Closing competition

The "hot phase" of competition is getting closer and closer. Wednesday is the day when we will get to know the other teams personally, and already on Friday our satellites will start if they pass the inspection on the day before.

The latest preparations are currently under way. Both CanSats are ready to go and meet the guidelines of the competition. The radio path is also stable and the ground station has been programmed.

We will always keep you up-to-date with daily reports. So it is worthwhile to visit our blog more often.

And of course we wish all teams a good flight and nice days!

Revision of the additional weight

Today we optimized our lead plates being used as additional weight. We added recesses for the cables.

first version of the lead plate...

and here the second version of the lead plate

Now it is easier to insert the CanSat into the outer casing. Now the plates weigh 8 g less (~82g).

Brief report about our four radio tests:

We have done four radio tests. Our communication works via WiFi and therefore we need a WiFi adapter for the ground station. The CanSat has an already integrated WiFi module.

The results we got from these tests were interestingly varied.

Finished outer casings

Today we finished our work on the outer casings. It should protect our CanSat against rain and other meterological effects and of course it should give the CanSat a cool look.
In all we made three outer casings, so we should be prepared if one of them fails.

Interested in how those were manufactured?

Twins

Today we finished our work on the second CanSat. It is a replica of the first one. This means we now have a replacement should one of the CanSats not work.

Additional weight for our CanSat

The guidelines require the CanSat to weigh between 300 and 350 grams. Because our CanSat only weighs 220 grams we needed to add at least additional 80 grams of extra weight to reach the minium weight.

We choose to use lead as extra weight again because of its high density and softness, but this time, instead of strapping strips of lead to the batteries with cable ties we choose to melt the lead in the same form our circuit boards are.

By doing so we are able to simply bolt the lead plate onto our CanSat like our circuit boards. The plate will be fixed to the bottom part of our CanSat in order to help stabilize the fall so our CanSat can take some steadier pictures.

mold drying

the materials we used

Further progress of our work on the CanSat

Till now we managed to produce a new and a much better version of our CanSat. And this is how it now looks like:

First progress

The meetings of Jan Philipp and Damian were in order to continue working on a new and a much better version of their CanSat without a radio module. And the results of their work from the 17th to the 20th of May are :

• They were able to save some space for other elements of the CanSat, in which they desoldered some unnecessary or unneeded elements of the Raspberry Pi 3.

These unneeded elements are one of two USB interfaces, the ethernet Interface and some Pins.

•  They also built the orientation module and the camera/sensor module all over again, but the sensors of the camera/sensor module were left the same. However the camera/sensor module has gotten a new PiCam and a new order of its elements (see here).

• The connection between the sensors is now more intelligible, because colored cables were added and the harness cables (wire harnesses )were knotted. 

Finally, no more chaos!

That is it till now, but it is not over yet.

We are back!

Finally, we have finished our exams so we can start working on our CanSat again! 

 

Our present plan foresees that we will keep our secondary mission, but we will improve it! Thus, individual technical components will be replaced. The Pi 2 B will be replaced by a Raspberry Pi 3, so more power is available for our software. As well, the current version (V1.3) of the PiCam will be replaced by the more recent one (V2).
Our basic concept of construction (boards with elements held together by 3mm threaded rods) has proven itself and will be therefore unchanged adopted.
As an innovation, we are currently testing whether we can replace the radio connection by a WLAN connection so that we can save the T-Minus radio module. To capture the signals we want to use a WLAN directional antenna. consequently, we are looking for a non-metallic shell for our CanSat, because our existing aluminum sheath would shield the WLAN.
The recovery unit should also be optimized. So we want to extend the joint between CanSat and the parachute (from 15 cm to> 50 cm) to counteract the pendulum movements during the fall.

That the current competition will take place internationally, so we will continue this blog in English.

More details / information will follow soon.