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Astra 1N - Any News ?


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Old 07-08-2011, 12:42
Analoguesat
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They said four orbits with burns at each apogee to circularise the GTO into GSO. So how long will each GTO orbit be? 24 hours? And what GSO orbital position will it start off in?

Also there did not seem to be any change in launcher characteristics for the change in 1N location and it seems to be up to the customer to move his satellite into the required orbital position, wherever that may be.
It doesnt really make much difference where the bird is eventually homed as they drift around the orbital arc anyway once they are are up on the orbital arc - the recently launched KazSat 2 can be seen to be moving slowly eastwards atm

http://www.lyngsat.com/asia.html

Where 1N will be tested still seems to be a secret - it wasnt mentioned during the broadcast. Ive asked SES on their fb page with the idea if you dont ask you dont get
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Old 07-08-2011, 12:46
Analoguesat
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What I want to know, and Analoguesat can probably tell us, is how long is it before 1N reaches it's GSO from GTO? I presume it's something like 5hrs (from snippits of info on Wikipedia)?
At least a week. - the solar panels wont be deployed until day 6. The first days of flight are involved in checking the satellite telemetry to see if she made it into orbit intact with no leaks (which is what killed Eutel W3B recently - she was abandoned the day after launch due to a major onboard propellant leak )
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Old 07-08-2011, 13:57
TelevisionUser
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For anyone who missed it, there's a clip of the launch here: http://www.youtube.com/watch?v=NXW89...layer_embedded
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Old 07-08-2011, 17:26
M60
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At least a week. - the solar panels wont be deployed until day 6. The first days of flight are involved in checking the satellite telemetry to see if she made it into orbit intact with no leaks (which is what killed Eutel W3B recently - she was abandoned the day after launch due to a major onboard propellant leak )
Interesting. So I presume they run a few GTO orbits before it's apogee reaches 36000km (i.e. GSO) and at that point, possibly in a few days, the on-board thrusters are fired to redirect her in to nominal GSO?

I remember the W3B incident, wasn't that built by Thales Alenia Space?
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Old 07-08-2011, 18:27
Analoguesat
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The orbital dynamics are complicated and Im not 100% certain of it all, but as i understand it

The launch vehicle puts the satellite into an elliptical orbit which has is apogee (furthest point) out near the 36000 km mark - eg on the orbital arc. The perigee (nearest point is a few hundred km up from the Earth directly after launch.

The onboard thruster on the bird are then used to raise the perigee over several days until the bird is in a circular orbit and on the Clarke Belt orbital plane.



Things are slightly different with the Proton launches from Baikonur - the part of mission where the bird is attached to the rocket are much longer (9 hours or so) as the Proton does much of the work of getting the bird up to geostationary orbit. They also have to reduce the inclination of the satellite as Baikonur is at 50N near enough.
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Old 07-08-2011, 18:36
grahamlthompson
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The orbital dynamics are complicated and Im not 100% certain of it all, but as i understand it

The launch vehicle puts the satellite into an elliptical orbit which has is apogee (furthest point) out near the 36000 km mark - eg on the orbital arc. The perigee (nearest point is a few hundred km up from the Earth directly after launch.

The onboard thruster on the bird are then used to raise the perigee over several days until the bird is in a circular orbit and on the Clarke Belt orbital plane.



Things are slightly different with the Proton launches from Baikonur - the part of mission where the bird is attached to the rocket are much longer (9 hours or so) as the Proton does much of the work of getting the bird up to geostationary orbit. They also have to reduce the inclination of the satellite as Baikonur is at 50N near enough.
Sounds right on the money to me

http://en.wikipedia.org/wiki/Geostat...transfer_orbit

As you say the maths is pretty complex
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Old 07-08-2011, 19:36
Analoguesat
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Sounds right on the money to me

http://en.wikipedia.org/wiki/Geostat...transfer_orbit

As you say the maths is pretty complex
I think my explanation is much simpler on the brain

I got lost after deltaV = 2V sin deltai/2
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Old 07-08-2011, 22:04
DaveCheltenham
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For anyone who missed it, there's a clip of the launch here: http://www.youtube.com/watch?v=NXW89...layer_embedded
or you can see the full replay from here.

Regards
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Old 08-08-2011, 10:27
Expat
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Astra 1N launch page pictures updated:
http://www.astra2d.com/astra1n_launch.html
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Old 08-08-2011, 10:47
Ace Grace
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So is this good news for us Freesat owners?
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Old 08-08-2011, 10:58
mersey70
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So is this good news for us Freesat owners?
I am no expert but what I have read suggests Astra 1N will be able to transmit certain channels with a tight UK beam, I guess with the intention of broadcasting free to air.

It sounds good. It still amazes me watching launches like this, very impressive (to me anyway).
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Old 08-08-2011, 12:37
M60
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So is this good news for us Freesat owners?
Yep, it sure is as, like mersey70 mentions below, it will allow channels currently encrypted on wide beams to go spot-beam and remove encryption. Channel 5's transponder is likely to do this, allowing 5* and 5USA to both go FTA and join Freesat, also ITV are to take three extra transponders (presumably for HD capacity) and likely to move their remaining encrypted sub-regions over to 1N too.

As has been pointed out by Analoguesat on the satellites.co.uk forum, 1N's TP's are much more powerful at 130w EiRP than 2D which is around 29w, according to SES data. As 2D gets away with using a fairly low FEC (Forward Error Correction), it may be that with 1N's power being much stronger then even lower FEC's could be implemented which will allow for more 'baseband' bandwidth out of each transponder than the current 33.79MB using DVB-S (S2 would give much more).

It's also been rumoured that the BBC may be about to move their remaining 2A TP's over to 1N too which carry BBC News, Parliament, interactive and all their radio services. This will please my relatives in the Canary Isles when I tell them!
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Old 08-08-2011, 17:16
belson
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the sky news also move to 1n ?
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Old 08-08-2011, 17:57
M60
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the sky news also move to 1n ?
I doubt it very much as Sky News would want to keep their widebeam transponder thus to cover the expats living in other parts of Europe. I guess they'll possibly gain something from this if the BBC do switch their remaining 2A TP's to 1N?
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Old 08-08-2011, 23:48
M60
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SES have now updated their site with 1N listed amongst their fleet. Going off the text below and on their 1N section of the site, it would suggest testing is to be done at 28.2E but we'll have to wait and find out:
http://www.ses-astra.com/business/en...ra1n/index.php

Following successful launch, the satellite is currently being moved to 28.2° East and will undergo testing before being made operational. ASTRA 1N will provide DTH broadcast services, notably digital and HD television. The satellite will offer coverage over Europe and will ultimately serve the German, French and Spanish markets. The satellite will first provide interim capacity at 28.2° East for the UK and Ireland before being re-located to 19.2° East.
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Old 09-08-2011, 06:49
Archvale
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interim capacity??????
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Old 09-08-2011, 08:41
Muzer
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interim capacity??????
In other words, it'll be at the Astra 2 position (28.2°E) until another satellite (Astra 2F, to be precise) can replace it. 1N's main mission isn't for 28.2°E, it's supposed to be at the Astra 1 position (19.2°E), which is why it's called 1N rather than 2E or something - it will just be at 28.2°E until 2F arrives.
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Old 09-08-2011, 08:47
madanglian
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Is 1N up then?



Went away for a couple of days, and missed it.

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Old 09-08-2011, 08:53
derek500
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It's also been rumoured that the BBC may be about to move their remaining 2A TP's over to 1N too which carry BBC News, Parliament, interactive and all their radio services. This will please my relatives in the Canary Isles when I tell them!
I would think it's highly unlikely the BBC would move its news channel or key radio stations from a widebeam.

I remember when 2d was launched and Radio Two was 'lost' to expats without large dishes. After complaints, It wasn't long before it moved back.

BBC News give hundreds of thousands of expats an alternative to Sky News. I'm sure the BBC will want this to remain available.
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Old 09-08-2011, 09:29
davesull
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Is 1N up then?



Went away for a couple of days, and missed it.

Yes, just before midnight on Saturday. You can watch a replay of the launch on Youtube if you're interested.
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Old 09-08-2011, 12:11
davesull
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I would think it's highly unlikely the BBC would move its news channel or key radio stations from a widebeam.

I remember when 2d was launched and Radio Two was 'lost' to expats without large dishes. After complaints, It wasn't long before it moved back.

BBC News give hundreds of thousands of expats an alternative to Sky News. I'm sure the BBC will want this to remain available.
Totally agree.
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Old 09-08-2011, 12:19
BKM
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BBC News give hundreds of thousands of expats an alternative to Sky News. I'm sure the BBC will want this to remain available.
I agree about the radio stations but, certainly in the case of hotels around even Europe, they invariably have BBC World rather than BBC News.
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Old 09-08-2011, 12:45
derek500
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I agree about the radio stations but, certainly in the case of hotels around even Europe, they invariably have BBC World rather than BBC News.
Expats don't live in hotels. They have their dishes pointed at 28.2 and many have a Sky sub with small dishes and do not get the BBC channels, except those on 2a.
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Old 09-08-2011, 12:46
Ray Cathode
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It's not the case for R5L & R5SX which are on 2D. Sports rights I believe.
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Old 09-08-2011, 15:19
kerry
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It's not the case for R5L & R5SX which are on 2D. Sports rights I believe.
All down to PL live transmissions. Most of the time 5 Live is available on line, but when live football is on air it goes to a recorded message if your IP address is out side the UK. Same reasoning applies to the narrow beam policy for 5 Live on satellite.
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