LIVE: Proton-M launch with Sirius FM-5 satellite - June 30, 2009

[William Graham]

Third and fourth burns have been completed.

[edkyle99]

Third and fourth burns have been completed.

Good 5th burn and satellite separation.  Mission success according to ILS mission blog.

 - Ed Kyle

[veryrelaxed]

Sirius is alive and talking

[Skyrocket]

Some questions on the further plans of Sirius:

Sirius FM6 (nearly identical to FM5) is planned to be launched next year to a Tundra HEO. I have heared somewhere, that it is to replace FM1 and(!) FM2. This would imply, that the HEO constellation would be reduced to two satellites with FM6 going into a new orbital plane. Can anyone confirm this?

ILS has another launch contract for a Sirius satellite. As until now no FM7 has been ordered, could this mean, that the 1st generation FM4 will be launched?

[vt_hokie]

Some questions on the further plans of Sirius:

Sirius FM6 (nearly identical to FM5) is planned to be launched next year to a Tundra HEO. I have heared somewhere, that it is to replace FM1 and(!) FM2. This would imply, that the HEO constellation would be reduced to two satellites with FM6 going into a new orbital plane. Can anyone confirm this?

That would be interesting...guess it would be 180 deg out of phase with FM-3.  It wouldn't allow them to have a satellite continuously over the northern hemisphere, so I don't know how well that would work.

[William Graham]

Some questions on the further plans of Sirius:

Sirius FM6 (nearly identical to FM5) is planned to be launched next year to a Tundra HEO. I have heared somewhere, that it is to replace FM1 and(!) FM2. This would imply, that the HEO constellation would be reduced to two satellites with FM6 going into a new orbital plane. Can anyone confirm this?

That would be interesting...guess it would be 180 deg out of phase with FM-3.  It wouldn't allow them to have a satellite continuously over the northern hemisphere, so I don't know how well that would work.

What are the advantages of tundra orbit over GEO anyway? Is it just coverage of higher lattitudes?

[Herb Schaltegger]

Some questions on the further plans of Sirius:

Sirius FM6 (nearly identical to FM5) is planned to be launched next year to a Tundra HEO. I have heared somewhere, that it is to replace FM1 and(!) FM2. This would imply, that the HEO constellation would be reduced to two satellites with FM6 going into a new orbital plane. Can anyone confirm this?

That would be interesting...guess it would be 180 deg out of phase with FM-3.  It wouldn't allow them to have a satellite continuously over the northern hemisphere, so I don't know how well that would work.

What are the advantages of tundra orbit over GEO anyway? Is it just coverage of higher lattitudes?

I was an XM customer before the merger so I never had to think about it, but I'm guessing it's to help look-angles to the satellite(s).  XM's constellation has issues in hilly or heavily forested terrain because you need to have a good view of the southern horizon.  They get around this in a lot of areas by using terrestrial repeaters (they have around 2,000 of them as I recall - so much for "satellite" radio, eh?  ) but I don't believe Sirius took that approach, choosing instead the tundra orbital scheme.

[anik]

Sirius FM6 (nearly identical to FM5) is planned to be launched next year to a Tundra HEO

Sirius FM-6 launch is planned in the fourth quarter of 2011.

[vt_hokie]

I was an XM customer before the merger so I never had to think about it, but I'm guessing it's to help look-angles to the satellite(s).

Yes, that's correct.

[Danderman]

Some questions on the further plans of Sirius:

Sirius FM6 (nearly identical to FM5) is planned to be launched next year to a Tundra HEO. I have heared somewhere, that it is to replace FM1 and(!) FM2. This would imply, that the HEO constellation would be reduced to two satellites with FM6 going into a new orbital plane. Can anyone confirm this?

That would be interesting...guess it would be 180 deg out of phase with FM-3.  It wouldn't allow them to have a satellite continuously over the northern hemisphere, so I don't know how well that would work.

What are the advantages of tundra orbit over GEO anyway? Is it just coverage of higher lattitudes?

I was an XM customer before the merger so I never had to think about it, but I'm guessing it's to help look-angles to the satellite(s).  XM's constellation has issues in hilly or heavily forested terrain because you need to have a good view of the southern horizon.  They get around this in a lot of areas by using terrestrial repeaters (they have around 2,000 of them as I recall - so much for "satellite" radio, eh?  ) but I don't believe Sirius took that approach, choosing instead the tundra orbital scheme.

The clear strategy for XM Radio/Sirius would be to merge the architectures so that a user would have access to both GEO and Tundra satellites. Since virtually all users today have boxes that can only access one set of satellites, how the company would transition to a single platform using both orbits remains a mystery.

[zaitcev]

I suspect that the orbital slots in GSO are precious these days, but I don't know exactly what political, organizational, and market mechanisms govern the access (except the broad division that ITU-T manages).

Beaming XM signal from Tundra orbit would be a neat trick. It is lower and so needs less power.

[Stan Black]

According to a comment on this
http://seekingalpha.com/article/237763-sirius-seeking-move-to-xm
they are abandoning the tundra HEO orbit