http://www.samspace.ru/News/foto.htm for more!

With the data from OLD, OBC and MASS combined, we can now understand what happened during the first 5.4 km of deployment that went rather nominal and very promising for the remainder of deployment (had not some OBC or OLD related problem decreased the OLD interrupt performance heavily at about 6300 s). Deployment speed during this nominal part of deployment is shown above, as registered by OLDs (until 6300 using OBC data, from there using integrated OLD rate data). After initial high tension phase due to excessive braking, the deployment speed is a bit too low. In order to correct, the brake turns to zero at t=70 s. The deployment friction is however a bit higher than expected. At zero turns it is identical to that of the nominal deployment friction at the nominal brake position (0.8 turn), so the deployment speed cannot catch up and remain slightly slower than nominal. In order to make up for the lost length, the deployment is allowed to accelerate until 2200 s by the controller. Then the controller continues to make corrections abruptly to keep the deployment on its path (2200-4000 s). We can be lucky that the deployment did not get stuck in this period, and it shows the winding proceeded to deploy smoothly. First stage completes with perfect length and an oscillation of 10 degrees, which is still acceptable for an accurate re-entry of Fotino.

Quentin and Marcel with their YES2 mock-up, made by Quentin with help of the rapid-prototyping machine of the ESTEC workshop. Don't be fooled, it was a few months of hard work, designing, manufacturing, polishing, coating and painting. Super job, Q! You may see more of those (smaller ones) at your Center of Expertise soon!

This is chapter 2 on the MASS post-eject attitude:

Above plot shows the magnetometer data, so the cosines of the angle with respect to the local magnetic field line of the Earth, for 3 orthogonal axes, in still arbitrary scale.

It can be seen that the data quality is good and the noise level small and identical for each of the channels (except some spurious data on Channel 2). At first glance the data seems to confirm the following things:

The above plot show the deployment tension in the first critical minute after ejection, as measured by the MASS tensiometer. The scale is TBD, but approximately in mN.

The braking of the cotton knots in the Kevlar that held the tether together during launch (tie downs) can be observed in the off-scale peaks at the expected times (0.3 and 2.5 seconds). The low average during this period suggest that the tie downs broke cleanly (also indicated by the nominal deployment speed after ejection). A clear rise in tension to about 0.2 N is then observed for several seconds (t=4.5 to t=6.5), as can be thought to be associated with the deployment of the 6 m long triple-thickness ripstitching section, expected to deploy at about this time interval. Then the tension level sinks down to a level of about 5 cN at t=8 s, which is very high compared to the expected level of about ~2 cN. The brake just started to increase at this point (in order to stabilize any oscillation of the MASS/Fotino). 

With Casi and Aage we are looking at the MASS data now. This system was added as a bonus in a 2 week crash effort before satellite completion to get some science out of the MASS subsatellite (its main purpose was to secure and release Fotino). So we cannot be very demanding on its results. We thus far are only able to decode data for the first 150 meters or so. Nevertheless, being the event just after the Grand Ejection of MASS/Fotino from FLOYD, this is significant information. It is a bit like the observable horizon of the Big Bang. With this data we have captured the following events that like in the Big Bang can be propagated according to better understood laws ;)

Hi everybody, I hope you are ok with this: I was noticing this email exchange in my gmail box started by Mihalis on Sept. 26, and thought it suitable to paste it onto this blog. It is amazing what we have achieved, and there should definitely be a drink organized where we get together at least once more... But when and where... What about the Delta-Utec office next month? Michiel

Good morning people!

First of all congratulations to all of you that contributed to YES2 and made a dream come true!
I feel very happy about the result of the mission, although the things didn't work out as expected...
but the result is not the point in this project...
the point is what we got from YES2...experience, knowledge, opportunities, hand's on job, patience, self control...
...and above all friendship!!!

Over the last week, we have been closely studying the data retrieved from the TSU, including detailed data from the length sensors (OLDs) and also some MASS data. The MASS data will tell us mostly about the initial conditions after ejection, so far it seems pretty nominal. More interesting however at this point is the raw data of the length sensors. We are hoping it can tell us why the deployment stopped or seemed to have stopped at 8.5 km. This data has to be combined with information from NORAD (who did not spot MASS nor Fotino in orbit after the mission) and with information from Foton and the DIMAC (accelerometers/magnetometers) payload.

Above graph plots the temperature of the XBOX and the OLD (tether core) vs. time and the various mission events. Initial temperatures are around freezing point. Self-heating takes care of almost all temperature change. The additional 6W heater inside the XBOX shuts off by thermostat after about one hour. Little effect of mission phase or even MASS/Fotino ejection (YTK2) can be seen, nor is there much effect of eclipse (approximately indicated with grey zones), as YES2 is pointed towards the Earth at this stage and MLI insulates the satellite. The change in temperature trend near the end of the mission (after YTK3) may be related to the reorientation of the Foton spacecraft along the velocity vector.

The YES2 project gave rise to many adventures. Marcin, Greg, Anton and Denis, a joint Polish-Russian team, was in place inside the nominal landing region in Kazakhstan, to catch a radio signal from Fotino, including re-entry data and homing beacon, and with plans for recovery based on ARGOS data. For this a mobile ground station was developed and of course agreed frequency of 437 MHz. Worries about transportation difficulties and harsh conditions were only partly true and were easily overcome by the pragmatic, resolvent crew. Astana is an ultra modern vibrant city and the roads are plentiful and good. But it was cold and rainy, and these conditions had to be endured for many hours, as Fotino was expected to descend from space on its northeastward trajectory over Kazakhstan.