Erik, Fabio and Michiel just had a reunion dinner in Sogni del Sud, a great small restaurant in Amsterdam. Highly recommended when you pass by, in the real Amsterdam outside the tourist area. The owner treats you wonderfully with whatever food he can think of on the spot. :) CU!

We have been working on a small ESA contract to evaluate critically the YES2 mission. Goal is to understand the problems that occurred during YES2 in order to prepare better for a future mission. Next step is to provide a new conceptual mission design. So far we have analyzed the mission in detail (see earlier reports or request the relevant papers); developed a hypothesis for the OLD problem matching flight and test data and demonstrated it in a test set-up (see previous report); and now we did the same for the quite high initial deployment tension. Cause of the high tension seems to be not so much the suspected increase in stickiness of the tether, but stiffness and memory and a settling of the tether into the grooves of the spool.

We wish all former YES2 members a productive, healthy and happy 2009!

As described in my previous message, the YES2 legacy continues. A 5 km tether has been wound for an experiment on Progress around 2011 (Baumann institute in Moscow). We are also started a YES2 reflight preparatory study on a Shtil (with Makeev) or perhaps Bion (in co-operation with SSAU). The Acta Actronautica paper with first mission results will be published very soon. The Aerospace America featured a nice summary of the YES2 mission data analysis in its overview of defining moments of 2008 (with a picture of Dimitris working on the satellite).  We have in the mean time also rebuilt the YES2 electronics system and we could reproduce similar behavior as seen in flight, which means that we have identified the likely cause of the failure of OLD electronics  that stopped the deployment control some 2300 s before deployment completed (brace yourself for some technical detail).

Congratulations everybody! 

I find it unbelievable but true. It's been already one year since the YES2 deployment, perhaps the most ambitious student space project ever. Time raced by, as I was studying the data from many many angles. And as it turns out from my analysis performed over the last 12 months, it was a highly successful tether experiment. There are so many sources of complementary and highly detailed  data that analysis will continue for at least one more year. But many essential results have already been obtained, first rough ones early this year, then improved/detailed during the Summer months.

• The ESA Education Office
• ESA HME
• ESA Technical Support
• TsSKB Foton Team
• Centers of Expertise
• The Students

Because of many requests, please find the Thank You poster attached.

Prof Belokonov announces the 5-th Russian-Eurpean Samara Space Summer School from 20-30 August 2008:

The program reveals interesting topics from YES2 to Earth observation satellites: www.volgaspace.ru/school.

Prof Belokonov says:"Wellcome for all students. New projects are waiting them."

In the days to follow (2-5 September) there will be a conference in Samara (just keep hanging around). There is a call for papers-deadline May 15th and topics like YES2 and flight opportunities for next Bion missions should interest you: http://volgaspace.ru/SPEXP2008/en/index.html

This colorful picture shows a fit of YES2 rate date (dark blue, loops per second vs. deployment time in the second stage, peaking at 65 Hz at deployment completion), as derived previously, vs. a recent spectrograph from RedShift's DIMAC accelerometers (green, yellow, red). Amazingly, the rattling of the tether (with a mass density of only 0.2 gram per meter) as it unwinds inside FLOYD [those who have been at the deployment tests know the sound of it!] is visible as accelerations on the 7000 kg Foton spacecraft, and shows up as a curve of high intensity in this plot of frequency vs. time . The match of the two independently determined curves provides direct evidence of the correctness of the deployment reconstruction by the YES2 team, as the overlay is near perfect, and confirms once more the full deployment of 31.7 km tether.

The fate of Fotino is better understood today. Based on deployment simulations including the MASS/Fotino attitude behavior, matched to DIMAC data, it seems likely that Fotino went through a rather nominal release and re-entry, and there is no reason to believe it would not survive:

- At the end of deployment, the shock was small enough not to induce full rotation of MASS/Fotino so the Fotino was probably not entangled in the tether.

- At the time of Fotino release, the Fotino was properly oriented and tether forces were optimal for separating Fotino effectively from MASS (similar to best case parabolic flight tests)

YES2, the tallest vertical structure ever made by mankind... As tall as 100 Eiffeltowers or nearly 4 times Mount Everest.