SiDS now open

How hard can it be? I mean, creating an SiDS server and making it available to anyone wishing to send frames in real time? That’s just about parsing an HTTP request, and saving stuff in the database. Piece of cake, really. After all, SiDS just means “Simple Downlink Share”, doesn’t it?

And yet… Bad request forwarding, slow server response time, access right issues, database collisions, we got them all! So, no, it wasn’t easy. And I can’t guarantee that there won’t be a few bugs left out here and there. But so far it seems to be working well enough.

I am glad to announce that the SiDS server for PicSat is now open and ready to process your telemetry frames!

In order to use it, you will need to go under your “profile” tab (don’t have an account on this website? Create one here!), and open your SiDS access by clicking on the button. You can also find the “source” that you should use when sending data. This should be your callsign if you have one, or your user name if not.

More info here:

A big thank to Mike DK3WN and Viljo ES5PC for their help in debugging that stuff!

P.S.: Sylvain F4GKR’s PicSat decoder PicTalk now allows for automatic forwarding of the data frames to the SiDS server!

P.P.S.: Telemetry forwarder also added to D3KWN’s PicSat Telemetry Decoder and Forwarder.


PicSat en français !

Nous y voilà ! Le site PicSat est désormais disponible en français, pour ceux qui préfèrent la langue de Molière à celle de Shakespeare !

Les News, quant à elles, seront tantôt en Anglais, tantôt en Français, selon l’humeur de l’auteur… Au pire, il y a toujours Google traduction !

Pour accéder à cette version, il suffit de cliquer sur le drapeau tricolore situé en haut à droite de la page.

Back online!

After a short appearance during the week-end of December 2 – December 3, 2017, our brand new PicSat website is finally coming back online !

This website describes the mission and its objective, and it will be used throughout the mission to provide a way for all radioamateurs listening to the satellite to upload the data they received, and collaborate to our mission.

Retrieving all the the photometry of Beta Pictoris 24/7 to detect an exoplanet or some exocomets passing in front of it will be hard. And we know that. But we hope that with the support of the community, we will be able to do just that!

We are in the final stage of our pre-launch activities in Meudon. PicSat is still on the ground, but it will soon fly to India and start its journey to space. In the meantime, we will connect this website to our “engineering model” (a spare copy of the satellite that we keep on ground), so that you can have an idea of what our data look like. Some maintenance has to be expected during the next few days.

But we promise: as soon as PicSat is in space, this website will show the true uncorrected raw data coming directly from it! We hope you’ll enjoy this opportunity to see how a space mission is operated, and to get an idea of the sparsity of data we have to deal with on a day-to-day basis…

Don’t forget to check our Twitter account IamPicSat for the latest news!

Space is hard: PSLV-C39 launch failure

Building and testing a satellite is an Herculean task. Making reliable software is exceptionally time-consuming and requires a lot of hard work. Building a working ground station and making sure that it can track a satellite moving at  8km/s above our head is tough. Making sure that the science instrument can reach the level of precision required for detecting the transit of Beta Pic b, and creating a database reliable and efficient enough to store all the data is a challenge all by itself. And today, we are recalled that launching a satellite into orbit — the only thing we were taking for granted so far — is also terribly complex and difficult…

The Indian rocket PSLV-C39, which lifted-off on schedule from Sriharikota, suffered from some sort of malfunction (apparently, the fairing did not separate), leading to the failure of the mission. More can be read on Space News or the Times of India.

PicSat is supposed to be launched on the next PSLV (codenamed PSLV-C40). At that time, we have no real info on what will happen to C40. But it would not really be a surprise if it suffers some delay due to the failure of C39…

Yeah, space IS hard.

Underperformance of the PSLV in late phase of the launch (upper plot is velocity relative to Earth vs time, and lower plot is altitude vs time; nominal expected curves and real data are shown). Credits: DD national.


In the vacuum chamber, no one can hear you scream

PicSat is back in the thermal vacuum chamber SimEnOm! After having cycled the payload electronic board v1.00, the payload electronic board v1.10, and the full engineering model, we are now cycling the flight model of PicSat! We have just removed the telescope so that our very talented optical team can continue working on the alignment. But there is no star in SimEnOm anyway, so that’s fine.

We are cycling the satellite from -20°C to +30°C. These are not extreme temperatures, but they are representative of the range we expect to have in space.

Installing PicSat in the chamber took quite a bit a time, as we had to be extremely careful not to damage anything, or deploy the solar panels by mistake. Oh, and yeah, we somehow found a way to forgot to put the latest version of the code on the payload board when integrating it into the satellite, so we also had to unscrew one side of the satellite to plug in the JTAG connector and (unsuccessfully) try to update it…

(management banned the picture here)

Uh? But wait a minute, haven’t we developed, wrote and tested a bootloader for this board, allowing updates to be performed remotely by radio? Yeah, but we kinda messed up with the versions here too…

ANYWAY, the main computer receives and replies to all our TCs (aka telecommands) smoothly; it tirelessly emits its beacon every 10 s; and we see all those sweet TM (telemetry) packets with our constantly changing, ever-evolving ground segment software! Plus, the faulty payload bootloader still accept/reply to some commands, so evreything is fine. There is even a beacon on the old payload app! So, really, what more could we ask for? Better version control / software quality management, maybe? Meh! Who needs that?

The main objective was to check the full communication chain at different temperatures, and thus the test campaign was unanimously considered a SUCCESS.

Next: vibrations!

Sylvestre is installing PicSat into the testPOD. Worry not: he was very well supervized during this operation.


Let there be light

And there was light.

It took us about a week of a very tedious and boring work, but we finally managed to get it done: all of the optical elements (that is: the two mirrors) of the payload are now aligned (well, sort of…). The springs used to  adjust the secondary mirror have been removed, and replaced with peelable washers (I’ll dedicate a specific post to those ones, they deserve it…). Everything is now hold in place by three brand new FHC M3x8 screws, coming straight from the observatory warehouse. By the way, I wonder how many PhD student at LESIA know this place…

With all the optics properly aligned, it it time to get the first serious image of the Point Spread Function (aka PSF) of the PicSat instrument. According to the theory, the PSF should be very close to a 2d gaussian of about 5 or 6 microns (Full Width at Half Maximum).

Starting scan:

[====================] 0%  (the piezo actuators are now purring)

[====================] 50%

[====================] 100%


Annnnd… here it is! Oh, wait a minute, is it really an 8×12 micron spot that I see here? And is that a secondary lobe over there?

I knew we should have gone for a Cassegrain!

The image of a point source (a single star), as seen by the fiber in the focal plane of the PicSat telescope.

A bootloader for our payload!

The photo only poorly renders the magnificence of what is happening here: the left diode of this STM32 based development board is actually BLINKING!

… What? A LED blinking software? Is that REALLY what we have been working on during these past few days? Don’t we have better than that to do?

Well, what you don’t know is that in the present case, this simple piece of software was not on the FLASH memory at first, and the LED was not blinking when the STM32 booted. Where did this new code come from, then? From these two orange and yellow wires, connecting the STM32 UART interface to a laptop. Yes, the program was transferred through this exact same interface that will connect the payload to the main computer of the satellite!

What this all means is that we will be able to update and/or reprogram the payload while in-flight! This will be used to correct the bugs to add some exciting new functionalities that we have yet to imagine!

Uh-oh. Did I just lose the perfect excuse to actually go up there with my JTAG connector?

A blinking LED on our STM32 dev board.