First post flight analysis

After the successful launch of Rexus 10 we still have a lot of things to do. There is a lot of data stored on the FFU which will have to be analyzed in order to fully understand how the system has behaved and recover the scientific data gathered by the experiment. This data is stored in the memory inside the e-box and has not yet been extracted as the FFU was wet after landing in the snow, and as water and electronics dont like each other we decided to leave it drying.

But probably you have already seen the video we posted yesterday. The images are impressive, but the main objective of mounting the camera was to film the FFU in order to be able to check how the spheres were deployed. Unfortunately the experiment module was coning (it had a quite high precession angle) and the FFU was lost from the field of view of the camera after a few seconds. However, if one analyzes the movie carefully can extract some useful information. On the pictures you can see some snapshots taken from the camera shortly after ejection, when the FFU was still in the field of view. Of one checks the pictures from 2 to 7 can see the doors of the SCALE systems popping out gradually (all four of them) which means that the SCALE systems were in fact working, as the doors can only be released if the motor of the wire boom systems are working.

The FFU also appears later on in the video. It was however very far from the experiment module and details can hardly be identified. One can see it in the last pictures, on the bottom half of the photos close to the edge of the ejection spring (dont get confused by the brilliant thing appearing on the top of the photos, which is the nose cone of the rocket). We were unlucky enough to have the sun very close to the area on which the FFU was flying, so on the photos it usually appears as a shiny thing close to the spring. There is however a very interesting photo. If one checks the very last picture, one can see the FFU body very close to the edge of the spring and what seems to be two of the spheres close to it.

We do know that at least two of the spheres were deployed, as when we recovered the FFU two of the cables had been damaged during reentry, probably because the motors driving the wire boom systems could not overcome the centrifugal force during retraction and stalled, leaving the spheres on the free airstream, which ripped them off the cable. We will not know surely how they worked until we really process the data, specially from the sensor wheels on the SCALE systems and of the gyros and accelerometers of the FFU, but so far so good.

Mario

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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.

Model rocket launches at Barnens Ö

Jacob writes

Back in April, David and me from SQUID and Johan and Erik from LAPLander headed out to Barnens Ö with Nickolay. It’s an island some distance from Stockholm, and in the summer it hosts camps for kids from the city. This time however, it hosted a camp for kids interested in astronomy held by the Egna Vingar foundation. We went there to talk about our projects, while Nickolay talked a bit about space weather. We got a lot of appreciation, and were even asked if we could come present more in the future. We also met a fellow space-blogger, Frida. Visit her blog at Frida och Stjärnorna (in Swedish)!

Erik had built two model rockets for the event, and we saw it as a great opportunity to try out our little shock-proof HD-camera. I’ve had the video for a while, but I thought it was high time I uploaded it!

The second rocket has an absolutely huge motor, and it was a pity it was so foggy. Erik estimated it might’ve reached an altitude of a 1000 meters!

I wanted to do the launches in slow-motion, but Windows is woefully ill-equipped for video editing and I didn’t have time to hunt around for better programs.

LAPLander videobloggar från Esrange

English: The LAPLander team is presently at Esrange space centre preparing their experiment for the flight, which is still a week off. Here are some of their videos from there, the first one in Swedish but the two others are in English. The team finished assembling their experiment yesterday, and this morning they went to find out if the tanks have stayed sealed or if there was an accidental airbag inflation during the night… check out the last video for the answer!

Här kommer lite videohälsningar från LAPLander-teamet, som nu är uppe vid Esrange och förbereder sitt experiment för uppskjutningen om ungefär en vecka. Den sista är från i morse, då de tittar till sitt ihopmonterade experiment. Håller tankarna tätt eller har airbagarna lösts ut under natten? :O

Dear readers, we need you! Besök ofta de närmaste dagarna och tipsa vänner och kollegor

Det är nu det gäller! Första delen av tävlingen KTH på Insidan går mot sitt slut i början av denna vecka, och vi måste vara bland de tre mest lästa bloggarna för att vinna pengar till projektet och gå vidare i tävlingen!

Det är därför viktigt att ni som besökare till den här bloggen tittar tillbaka varje dag, och tipsar vänner och kollegor. Vi lovar att ha nya fräscha inlägg flera gånger om dagen!

English Summary: Please visit our blog frequently the coming days as the first stage of the KTH on the Inside Competition is drawing to a close and we need to be among the top 3 most read blogs to win money for our project and qualify for the next round!

MEFISTO Vibration test

One of the main objectives of the SQUID project is to deploy several wire booms. The system in charge of deploying these wire booms is called SCALE, and a very similar system called MEFISTO is being developed at KTH for the BepiColombo mission from ESA/JAXA, which will be launched to Mercury in 2014.

Last Thursday we performed a vibration test at Kista, where the instrument was subjected to a very severe vibration test in order to prove that it will survive to the launch. The instrument we tested was not the final design, and it was used mostly to validate the FEM model and detect possible problems on the design.

The test went really well, showing that the design was very robust and only some minor weak points where detected. The video posted below shows one of the hardest vibration tests the dummy had to withstand, and it is specially interesting to see how at the end of the test the door of the system (left side) starts bending and some “white things” start falling from the instrument. Those “white things” where actually pieces of adhesive that where used to attach one of the parts, which obviously wont be case in the final design, but due to some manufacturing problems it was not possible to screw the parts before the test, so a fast and improvised solution was made. The adhesive however, was not good enough to survive to the test:

As you can see, vibration is an important thing to consider when designing space hardware, and with SQUID we will also have to deal with it!

Att falla tillbaka till jorden är också jobbigt

Även fast sondraketerna inte har lika hög hastighet som t.ex. rymdfärjan när de faller tillbaka in i atmosfären, utsätts de för mycket större G-krafter. Detta är för att de faller nästan rakt ner i de tjockare luftlagren, medan rymdfärjan kommer in i en snäll vinkel.

Med båda fötterna på jorden utsätts man för 1g, sin vanliga tyngd. Astronauter i rymdfärjan utsätts för runt 3g vid uppskjutning och återfärd. Människor har överlevt över 100g under mycket korta stunder, t.ex. vid krasher under racerlopp, men vanliga bilkrasher som kan vara väl så farliga är ofta bara bråkdelen av det.

REXUS-raketen utsätts för nästan 19g när den skjuts upp, och 5-10g när den trillar tillbaka från 90 kilometers höjd; MAXUS-raketen, som färdas upp till 700 kilometers höjd, träffar å andra sidan atmosfären i drygt tiotusen kilometer i timmen och utsätts för 40g, under flera sekunder! Inget för astronauter med andra ord.

Hur kan då detta se ut från raketens synvinkel? I videon nedan ser man först hur motorn separeras från den delen av raketen som innehåller experimenten. När raketen bromsas upp som mest runt 4 minuter in klarar kameraglaset knappt av g-krafterna och trycket från luften… Mulningen i snön i slutet blir för mycket.

Ljuden i bakgrunden är nog vibrationer i raketens struktur från systemen ombord. Vid återinträdet verkar det extrema vindbruset blir för mycket för kamerans mikofon.

REXUS-uppskjutning – Så här kan det se ut

Schemat är späckat så just nu innan avslutningsmiddagen hinner inte riktigt göra en ordentlig uppdatering över veckans sista dagar. Vi lovar att fixa upp bilderna så snart som möjligt.

Istället bjuder vi på en cool informationsfilm om REXUS, som svenska Rymdstyrelsen, SNSB, har satt ihop. Den fokuserar på de sista frenetiska dagarna före uppskjutningen av REXUS 5/6 i Februari-Mars förra året.