GNSS Satellite (GIOVE-A)


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Wednesday, 26 August 2009

GLONASS Launch Schedule Update

As in 2008 the GLONASS schedule promises again two triplet launches this year. The first one to take place on September 25, just like in 2008. The second is planned for the meanwhile "traditional" Christmas launch around the end of December. The first satellite for the September launch has been shipped to the Baikonur spacedrome and launch pad in Uzbekhistan. The two other satellites will follow in late August and early September.

Currently there are 18 healthy dual frequency GLONASS satellites. With the two triplet launches of this year the constellation should reach the "magical" number of 24 satellites which is the amount of satellites needed to reach to so-called "full orbit constellation" (FOC). However, for FOC each of the three orbital planes of the GLONASS system will need 8 satellites. Currently the planes have 5, 5, and 8 respecitively. So most likely the launch in September will be used to populated plane I which has the oldest satellites. The December launch will then repopulate plane II.

Plane I has two rather old satellites, by GLONASS standards, one from 2003 (SVN-701 in slot 6) and one form 2004 (SVN-712 in slot 7). These might die before the end of this year. The offical planned FOC data is by the end of 2010. In 2010 two more triplet launches are planned again in September and December.

The really exiting part of that will be the launch of the the new platform, the GLONASS-K satellite. One of the 3 satellites to be launched in December 2010 will be a GLONASS-K satellite. The most important features of this new GLONASS satellite generation are:
  • Longer life time, design life time of 10 years
  • Much lighter satellites reducing launch costs and enabling launches with Soyus rather then with the huge and costly Proton launcher
  • Addition of GPS-like CDMA signals.

The addition of CDMA, in paralel to the GLONASS original FDMA signals, will make GLONASS interoperable with GPS (and Galileo). This will enhance the interest and usage of GLONASS even further then its already rapidly spreading usage.

The GNSS future looks very interesting and very bright!

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Monday, 10 August 2009

Last launch of GPS Block IIR Satellite

On August 17 the last GPS Block IIR satellite will be launched. It will be named SVN50/PRN21. This launch is the end of the aera of the Block IIR, "replenishment", satelites. The next satellite generation to be launched will be the Block IIF, "future", satellites. Of course the lifetime of 10 years will mean that we will use GPS Block IIR satellites for the next decade.

SVN50 will be placed into orbital plane/slot E3, replacing SVN40, a Block IIA satellite launched in July 1996 that is past its design life but still working well. SVN40 will be moved a little further along the orbital path. Successful launch and activation of the new satellite will bring the constellation to 31 operational satellites, not counting SVN49 which is still set unhealthy due to its signal anomaly.

Here it is important to note that SVN50 will not have any payload connected to the J2 auxiliary payload port that proved problematical with the L5 demonstration payload on SVN49, and possibly on other Block IIR/IIRMs.

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