Marco Langbroek responded to Allen Thomson: > > Lacrosse 5 is still doing its odd rapid "disappearance trick"... > > > > As has probably been mentioned, the only explanations that seem > > to make sense are that it has a large specular or very black > > surface that hides the main body at certain angles. The specular > > surface would hide the main body when it's oriented to show the > > observer a view of black space. What that surface might be is a > > planar radar antenna or maybe (I don't think so, but maybe) a > > solar panel. > > It has to be something like that, yes. Back in March I have > reported a number of timings for the "disappearance trick" > too so perhaps it is possible to correlate these to a certain > spacecraft attitude. There seems to be some consensus among analysts that Lacrosse's radar antenna was dish-shaped. Here is Charles Vick's conceptual drawing: http://www.globalsecurity.org/space/systems/lacrosse_onyx-schem.htm To replace the dish with a planar antenna, would be a fairly significant design change. Have the observers who take high-resolution images of spacecraft reached any firm conclusions on this? > Lacrosse 5 clearly is an odd bird compared to the earlier Lacrosses: > > * it is brighter (visually and photographically); > * instead of red-orange it is yellow in colour; > * the other Lacrosse-birds don't do the "disappearance-trick" > (instead, they show short flares) It is also the first not to employ a frozen orbit. Considering that the program must be about 25 years old, it is not surprising to see some changes. Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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