EVOL.reverse

Seems one of the developers that was working on one of the modules asked what icons should be shipped with the software and the client said it wasn’t important so he ended up choosing some icons according to his own taste.. which is kinda cool because now I’m working on the software and have these funny icons on the desktop:

The guy didn’t use the default gray icon, he wanted something better and funny and not the minimum that can be gotten away with. By the way, the icon on the right is Frank Zappa.

We cycled to Ludwigshöhe Tower and then to Roßdorf via Ober-Ramstadt.

We cycled through Griesheim, Wolfskehlen, and Leeheim, which is basically where the road goes. From Leeheim, we carried on straight to the Rhine through Sonnenhof and on to Kornsand, whereas the road goes north a bit through Geinsheim. It took about an hour to get there.

This map shows it quite well… click here.

There is this thing called “Time Correlation” and questions about it pop up in work every now and then. I’m just now beginning to scratch the surface of what this thing is and thought that writing something down here and explaining it might help organize my thoughts and give a small glimpse of what this is.

Timestamping the things that happen on the spacecraft (e.g. execution of commands, transmission of data, instrument measurements, etc) is very important as one can imagine. It is not so simple as putting a normal (or even a very good quality) clock on-board because it is known that clocks drift from actual time every once in a while. This led someone to come up with a very simple scheme to determine more accurately the time on-board.

This scheme begins by having a simple counter on-board. We can think of this counter as a simple integer sequential counter that counts 1,2,3,4, etc. incrementally. This counter is sampled every N frames (think sequence of bytes if nothing else) that are sent by the spacecraft and a packet is created with the counter value.

At the ground, the reception time of the frame is recorded and associated with the counter value in a pair. By looking at several of these pairs and performing a correlation it becomes possible to convert the integers into actual UTC time.

Here’s the funny thing, the counter value is sampled at the exact moment one of this frames begins being transmitted. It is not possible to sample the counter and transmit at the same time (maybe because of the backlog queue of frames?). This means the sample value will be delivered later on a separated packet, one that is not included in the frame just transmitted. So what do we do? Since the counter is sampled every N frames we look into the previous Nth frame and its reception time on earth * and save it until we get the next sample value. Once we do, we are sure that, if we subtract the transmission time from the value we had saved, we will get the time of last sample of the counter value

This is a bit tricky at first but extremely easy once you get it. I’m happy to try to answer some questions on it if anyone’s interested.

And this was the whiteboard after some drawings on time correlation..

* Since the orbit of the spacecraft is modeled on earth we know at each point how long it will take for such a transmission to get to earth. This can go from seconds to hours as you can imagine (depending on the distance, etc). This transmission time is called One-Way-Light-Time (OWLT).

Most people work in their home country and go on holidays abroad. This year we decided to do it the other way around, to work abroad and go on holidays to Portugal. Well, actually its more complicated than that but what matters is that we now have bought our tickets to Portugal for our vacations. We’re going on the 25th of July and returning on the 10th of August. After all, Portugal is one the best holiday locations I know of (if not the best attention I’m biased).  I hope to get together with my friends, catch some sun and bath on the ocean again.

A couple of weekends ago I went to Oppenheim I found this formula in several doors around the village. I was so intrigued I had to ask what it was all about. It seems it’s a catholic custom. The “Sternsinger” (star singers) are kids dressed up as the kings from the east (http://en.wikipedia.org/wiki/Biblical_Magi) roaming the towns and villages collecting sweets for themselves and donations (money) for the church.

When those kids visit a house they leave that strange formula written on it. Thanks to Joerg for the explanation

I don’t smoke but couldn’t resist taking this photo. It features a box of cigars just bought from a vending machine on the street. The funny thing is that you normally get 22 cigars for 4 euros in Germany but since from these machines you can only get 17 cigars, the refund is packed with the box illustrated by this curious picture.

Today as we were leaving the floor a user came rushing after us to show us this image of the Phoenix spacecraft landing on Mars (from 2 days ago). I was quite surprised and found it to be a very nice gesture. Thanks.

While it may seem as this picture reflects a drug apprehension, in fact, its only a photo of all the pieces that we had to put together to install our wardrobe. If you fancy puzzles you might as well go to Ikea instead of a puzzle shop