The first launches of SQUID: Spring and RID testing

Yesterday the rocket interface disc, RID, finally arrived. This is the piece that actually mounts the free-flying unit, FFU, to the rocket. The custom made wave spring that will eject the FFU arrived a couple of weeks ago, and now we could finally mate them together.

The rocket interface disc (RID) with the ejection spring

However it soon became apparent that the spring had a tighter fit in the spring gully than we had expected, and to determine whether this would affect the ejection or not me and Mikko carried out some spring testing.

Soon half of the team had gathered around to watch and help out as we covered a sturdy table down in the workshop with foam and devised a clever way of holding the bottom plate of the FFU down against the spring. An unlucky Mario was selected sit under the table and cut a rope going down through a hole in the bottom plate and rid, and down through the table where it was hooked up to a tightening mechanism. To document the ejection we borrowed a Casio high-speed camera from the department of mechanics.

We did two “launches” today, and while the launches weren’t as straight as they could have been the results seem positive, especially since the weighted-down bottom plate was not perfectly balanced. However, since the radius of the spring is slightly lower than expected the very top part of it easily gets jammed between the bottom plate of the FFU and the RID. More testing will be done soon, but until then enjoy the fancy high-speed videos! Sorry for not having turned them right way up, but this would decrease the video quality.

The flickering is due to the flourescent lighting in the room,  and the towel in the first video was an attempt at catching the falling plate. 🙂

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The SCALE system is spinning

During the past week we’ve finally done some real progress on the SCALE system . For those of you who are not totally up to date with that the SCALE system is please check out these posts. To make a long story short, the SCALE system is probably the most central part of the whole experiment, it’s a complex mechanical structure which has one task, to deploy and retract the spherical probes which are used to make the measurements of the electromagnetic field. Due to the drastic changes we had to perform on the landing system the SCALE system where somewhat overseen and tasks which should had been performed much earlier during the project still remained when the team gathered after the summer. However due to great efforts performed by mainly Malin and Mario the system is now finally running and we now focus on optimizing the functionality of it. Below are two videos which displays the system and how it works.

 

Parachute load test with an unexpected outcome

Last Thursday it was time to determine once and for all how much the parachutes we use in the landing system could handle. Having failed to break them in both the car towing test and the actual drop test, me and our supervisor Gunnar Tibert resorted to more brutal methods.

One of the 70″ parachutes was hung upside down from a hook in the Structures Lab at KTH, supported by a single line of paracord which was to brake the fall. This is the same type of cord that was successfully used in the drop tests above Esrange. The parachute was loaded with about 19 kg of extra load, and dropped with 1.5 m of slack paracord.

Sometimes it's best to use what you have closest at hand! 19 kg of old newspapers have just the right density to fill out the parachute nicely.

Much to our surprise, it turned out the paracord, which we thought was rated to the equivalent of a couple of hundred kilograms in force, was the weakest link:

View from the hook of the crane, filmed with the GoPro HD Hero.

420 FPS high speed footage shot using a Casio consumer camera. This doesn’t show the paracord breaking, but is cool nontheless!

Right now we’re trying to determine the speed right before and after the line broke so we can calculate the force in the cord. At any rate, it is likely we will switch this cord for the real system to be sure that the same won’t happen during our flight! However, the cord still needs to be flexible so the shock to the experiment isn’t too great.

busy, busy, busy

I just realized, it seems we were too busy to actually inform you about all our problems and the work that has happened on the structure and especially on the deployment system during the last couple of weeks.

When we started to put the SCALE-system together about six weeks ago we found out, that we actually had some pretty big problems with friction, and where not really able to feed out the cable at all. The main problem here was the feed through mechanism of the main cogwheel where the cable is supposed to glide through easily. Now after a lot of trial and error and some help the system is working and it’s amazing how much better the feed-through works now.  So much about summing up the biggest problem we had recently. However I hope Malin finds some time soon to fill you in on the more detailed progress on the SCALE.

Then more recently we thought about panicking on Friday, because the M-Beam

– Team from Austria called us in order to get some more space. There experiment is going to sit right below ours in the rocket and we had discussed how much space they need, but for some reason it got bigger anyway. After some discussion it seems to be the easiest if we just raise our experiment a bit. Still we got kind of shocked and M-Beam seemed to be pretty desperate at first. I just hope we don’t experience any more problems due to that issue.

Fortunately there is something going according to the plans  (at least almost) and the manufacturing of the flight versions of some different parts has started. The first flight frame is finished, David is working on the first set of walls, which seems to be difficult, but with some training I am sure he will manage to bend them in a way so the fit “perfectly”. Then for next week it is planned, that all parts for the RMU are finished, and with some luck we will even have the outer housing of the first FFU done and finished.