Nano that is a different case from what I am talking about, and certainly in the case of Astra 2D you could almost set your watch by the diurnal power fluctuations. When a satellite does the same thing day in day out, month in month out, and the satellite in the adjacent slot does the complete opposite it is unlikely to be anything to do with the time of day or atmospherics, and more likely to be down to how well the solar array is illuminated or the satellite's ability to maintain stable attitude control over the 24 hour period.nanochickin said:Actually Huevos on that bit your wrong. The atmosphere can play as huge role in how the signal is effected.
Huevos said:Nano that is a different case from what I am talking about, and certainly in the case of Astra 2D you could almost set your watch by the diurnal power fluctuations. When a satellite does the same thing day in day out, month in month out, and the satellite in the adjacent slot does the complete opposite it is unlikely to be anything to do with the time of day or atmospherics, and more likely to be down to how well the solar array is illuminated or the satellite's ability to maintain stable attitude control over the 24 hour period.
The 2D thing is not down to the satellite moving around in its box. The reason I say that is because the satellite not holding station does not follow a daily rhythm. It also is not down to the atmosphere or being night. Here's why. Where I am horizontal transponders are almost impossible on a 2.4m dish. 100km north of here (on the same size dish) horizontal transponders are lockable in the morning and continue through most of the afternoon and then drop below the receive threshold some time around 5 o'clock. On the other hand 100 km south of here the same transponders can't be received all day, but they appear about 6 o'clock and are receivable for most of the evening. This has been going on since the satellite arrived at 28ºE. To me this suggests there is a slight north/south shift of the satellite's footprint over each orbit. I've no idea what causes it but I can't come up with any other explanation for this phenomenon.M60 said:I suppose with the acceptance angle of a 2.4 or 3.1mtr dish being 0.5deg or less then any fluctuations in the satellites orbit within it's "box" as it were, are going to cause issues.
dvdfilm said:at this point are the tracking sites still reliable regarding Astra 1N position or would the orbit be already modified by the control station?
Analoguesat said:As soon as she starts decelerating to slot at 28E the tracking will become unreliable for a couple of days until its corrected. In the past Ive seen it take anything up to a week for a newly geostationary bird to be correctly identified on n2yo
It's not deceleration, it is acceleration. This is kind of contrary to rational thought because in its current orbit it is moving forward faster than geostationary, but to get it to geostationary it needs to be accelerated to a high speed. After the burn the satellite has more forward speed and this throws it further out, but by the time it arrives at the higher orbit that speed has been absorbed (by gravity) and it is then moving forward at a slower speed than its previous speed in the lower orbit. On the other hand, when a satellite is being drifted from east to west the opposite is true because an east to west drift requires the orbit to be raised above geostationary (so it goes slower than the sidereal period of the Earth).M60 said:Won't the deceleration only take place when the orbit raising burn is carried out so in effect the satellite will only slow down so it's in exact movement with the Earth and thus seen as 'stationary' from the Earth viewing perspective? The satellite won't in effect be slowed down, surely the orbit raising procedure will slow it's speed to that of the earth's rotation (being lowered somewhat it's currently in a faster Earth orbit so thus seen as 'moving' from our perspective being on the planet!).
Huevos said:It's not deceleration, it is acceleration. This is kind of contrary to rational thought because in its current orbit it is moving forward faster than geostationary, but to get it to geostationary it needs to be accelerated to a high speed. After the burn the satellite has more forward speed and this throws it further out, but by the time it arrives at the higher orbit that speed has been absorbed (by gravity) and it is then moving forward at a slower speed than its previous speed in the lower orbit. On the other hand, when a satellite is being drifted from east to west the opposite is true because an east to west drift requires the orbit to be raised above geostationary (so it goes slower than the sidereal period of the Earth).
Actually it is the opposite. The first burn speeds it up but once it reaches the higher orbit it has lost the extra speed used to overcome gravity and so it drops back down to the lower orbit. If left without any further burn it would oscillate between the lower altitude and GSO altitude over each successive orbit. What the second burn is for is to give it more energy to keep it at GSO, not to take speed out.M60 said:another slight opposite burn be required to, in effect, stop it where they want it?
Zorba said:Edit - No wishes for spacecraft destruction if you please - admin.
Huevos said:Actually it is the opposite. The first burn speeds it up but once it reaches the higher orbit it has lost the extra speed used to overcome gravity and so it drops back down to the lower orbit. If left without any further burn it would oscillate between the lower altitude and GSO altitude over each successive orbit. What the second burn is for is to give it more energy to keep it at GSO, not to take speed out.
Where did you get that solly? n2yo still has 1N at 27.5Esolly said:satellite now 27.90e