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| Europe’s 11th and 12th Galileo satellites being unloaded from their Boeing 747 transporter after landing at French Guiana’s Cayenne-Félix Eboué Airport on 30 October 2015. |
Showing posts with label Galileo (GNSS). Show all posts
Showing posts with label Galileo (GNSS). Show all posts
Nov 4, 2015
Galileo's Initial Services Will Start 2016 (According to ESA)
The launch of the 11th and 12th satellite in the series on 17 December will mean that the total number of Galileo satellites in space will have doubled within a year, setting the Galileo program on track for the start of initial services during 2016. (See the time table.)
Jun 23, 2015
Galileo More Successful (March 27, 2015)
The previous two satellites Galileo #5 and #6 (FOC #1 and #2) launched in 2014 ended to wrong orbits due to problems in the launch vehicle (see this article). Now the orbit insertion for Galileo #7 and #8 (FOC #3 and #4) happened flawlessly and brought relief to Europe's GNSS program.
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| Galileo launch profile |
Nov 23, 2014
Galileo Started Badly (August 22, 2014)
Europe's satellite navigation system Galileo's full operational capability (FOC) phase started badly (22.8.2014) due to a design error in the Russian launch vehicle Soyuz-STB Fregat-MT. This is the first partial failure since 2011 for the Soyuz vehicle and about 20 successful launches since the 2011 failure. The problem left the pair of satellites (FOC-1 and FOC-2) in the wrong orbit, with higher apogee, lower perigee and an incorrect inclination compared to the planned circular orbit (see below).
[News update Jan. 5, 2015: After some maneuvers the FOC-1 orbit could be fixed to some degree and the same recovery maneuvers are planned for the sixth satellite (FOC-2), taking it into the same orbital plane but on the opposite side of Earth. The decision whether to use the two satellites for Navigation and SAR purposes as part of the Galileo constellation will be taken by the European Commission based on the test results later.]
“After launch, we quickly discovered that one of each satellite’s pair of solar wings had not deployed correctly,” says Liviu Stefanov, Spacecraft Operations Manager. “At the same time, difficulties in receiving radio signals – indicated by unusually low power and instability – alerted us to the fact that the orbits could be incorrect. Basically, the ground stations were pointing to where we expected the satellites to be, and they weren’t there, so we weren’t getting good signals.”
It took three days to release the trapped solar wing of the first satellite, and then two days later the second Galileo’s stuck array was also freed.
It was determined that the best course of action would be to dedicate most of the vehicle’s propellant to raising the perigee (lowest point) of the orbit from 13,713 to 17,339 Kilometers. Once in that orbit, the satellite would be out of the most intense areas of radiation. Although the two spacecraft will not reach their nominal working orbit, “the new orbit will fly over the same location every 20 days,” said Daniel Navarro-Reyes, ESA Galileo mission analyst. “The standard Galileo repeat pattern is every 10 days, so achieving this will synchronize the ground track with the rest of the Galileo satellites.”
Galileo FM01 is a 733-kg (660 kg dry) navigation satellite, one of the first two Full Operational Capability (FOC) satellites. These satellites carry two rubidium and two hydrogen maser atomic clocks and broadcast on L-band. They also carry the MEOSAR search and rescue transponder payload. They are built by OHB (Bremen) with navigation payloads by SSTL (Guildford). The earlier IOV test satellites were partly owned by ESA, but the FOC satellites are owned by the European Union's GSA (Global Navigation Satellite Systems Agency).
The spacecraft were placed in a wrong orbit. As planned, the Fregat upper stage made its first burn to put both satellites into in elliptical transfer orbit and then made a second burn intended to circularize the orbit at 23,500 km, inclined at 55.0 degrees. Unfortunately, the orbit was 13,700 km x 25,900 km, inclined at 49.7 degres, more elliptical than planned and with the wrong orbital inclination.
Russian officials report that the failure of the Fregat stage was caused when a cryogenic helium line installed too close to a hydrazine propellant supply line caused the hydrazine to freeze. The root cause was a design error, not a quality control error.
RESOURCES
/1/ http://galileognss.eu/first-galileo-foc-satellite-moving-to-new-orbit/
/2/ http://claudelafleur.qc.ca/Spacecrafts-2014.html#GalileoFOCFM1
/3/ http://claudelafleur.qc.ca/Spacecrafts-2014.html
/4/ http://en.wikipedia.org/wiki/Galileo_%28satellite_navigation%29#List_of_satellites
[News update Jan. 5, 2015: After some maneuvers the FOC-1 orbit could be fixed to some degree and the same recovery maneuvers are planned for the sixth satellite (FOC-2), taking it into the same orbital plane but on the opposite side of Earth. The decision whether to use the two satellites for Navigation and SAR purposes as part of the Galileo constellation will be taken by the European Commission based on the test results later.]
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| Galileo FOC-1 and FOC-2 orbit errors |
“After launch, we quickly discovered that one of each satellite’s pair of solar wings had not deployed correctly,” says Liviu Stefanov, Spacecraft Operations Manager. “At the same time, difficulties in receiving radio signals – indicated by unusually low power and instability – alerted us to the fact that the orbits could be incorrect. Basically, the ground stations were pointing to where we expected the satellites to be, and they weren’t there, so we weren’t getting good signals.”
It took three days to release the trapped solar wing of the first satellite, and then two days later the second Galileo’s stuck array was also freed.
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| Galileo FOC Satellites |
It was determined that the best course of action would be to dedicate most of the vehicle’s propellant to raising the perigee (lowest point) of the orbit from 13,713 to 17,339 Kilometers. Once in that orbit, the satellite would be out of the most intense areas of radiation. Although the two spacecraft will not reach their nominal working orbit, “the new orbit will fly over the same location every 20 days,” said Daniel Navarro-Reyes, ESA Galileo mission analyst. “The standard Galileo repeat pattern is every 10 days, so achieving this will synchronize the ground track with the rest of the Galileo satellites.”
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| Soyuz 2-1B, Galileo FOC-1 and 2 Launch, August 22, 2014 |
Galileo FM01 is a 733-kg (660 kg dry) navigation satellite, one of the first two Full Operational Capability (FOC) satellites. These satellites carry two rubidium and two hydrogen maser atomic clocks and broadcast on L-band. They also carry the MEOSAR search and rescue transponder payload. They are built by OHB (Bremen) with navigation payloads by SSTL (Guildford). The earlier IOV test satellites were partly owned by ESA, but the FOC satellites are owned by the European Union's GSA (Global Navigation Satellite Systems Agency).
The spacecraft were placed in a wrong orbit. As planned, the Fregat upper stage made its first burn to put both satellites into in elliptical transfer orbit and then made a second burn intended to circularize the orbit at 23,500 km, inclined at 55.0 degrees. Unfortunately, the orbit was 13,700 km x 25,900 km, inclined at 49.7 degres, more elliptical than planned and with the wrong orbital inclination.
Russian officials report that the failure of the Fregat stage was caused when a cryogenic helium line installed too close to a hydrazine propellant supply line caused the hydrazine to freeze. The root cause was a design error, not a quality control error.
On 22 August, at 12:27 GMT/14:27 CEST, a Soyuz rocket launched Europe’s fifth and six Galileo satellites from Europe's Spaceport in Kourou, French Guiana. Rewatch the moment of launch here.
RESOURCES
/1/ http://galileognss.eu/first-galileo-foc-satellite-moving-to-new-orbit/
/2/ http://claudelafleur.qc.ca/Spacecrafts-2014.html#GalileoFOCFM1
/3/ http://claudelafleur.qc.ca/Spacecrafts-2014.html
/4/ http://en.wikipedia.org/wiki/Galileo_%28satellite_navigation%29#List_of_satellites
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Oct 20, 2011
Launch Date Today; Galileo IOV 2 First Satellites
Galileo IOV (In Orbit Validation) 2 first satellites should be launched today or tomorrow in Guiana Space Centre, French Guiana using Russian Soyuz ST-B launcher with Fregat-MT upper stage. /1/
These 2 satellites are the first two satellites of the actual Galileo system consisting of 30 satellites. Until now different tests have been going on with preliminary type Galileo satellites.
Soyuz - Galileo IOV launch delayed
At the moment: 20 October 2011, following an anomaly detected during fueling of the Soyuz launcher’s third stage, the final countdown has been interrupted. Soyuz and its two Galileo IOV satellites, along with the launch facility, have been placed in a safe mode. A new launch date will be announced later today. /2/
And here it goes
Here is more about the Galileo and factors affecting its accuracy.
RESOURCES
/1/ http://www.esa.int/SPECIALS/Galileo_IOV/SEM7DEITPQG_0.html
/2/ http://www.esa.int/SPECIALS/Galileo_IOV/
Galileo IOV Satellite
These 2 satellites are the first two satellites of the actual Galileo system consisting of 30 satellites. Until now different tests have been going on with preliminary type Galileo satellites.
Satellites waiting on a Soyuz launch vehicle to be launched
Soyuz - Galileo IOV launch delayed
At the moment: 20 October 2011, following an anomaly detected during fueling of the Soyuz launcher’s third stage, the final countdown has been interrupted. Soyuz and its two Galileo IOV satellites, along with the launch facility, have been placed in a safe mode. A new launch date will be announced later today. /2/
And here it goes
Here is more about the Galileo and factors affecting its accuracy.
RESOURCES
/1/ http://www.esa.int/SPECIALS/Galileo_IOV/SEM7DEITPQG_0.html
/2/ http://www.esa.int/SPECIALS/Galileo_IOV/
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May 1, 2009
SPOT Messenger and Galileo GNSS
With the SPOT Satellite Messenger help is always within reach. Check the following video for more details.
http://international.findmespot.com/
Galileo GNSS (Global Navigation Satellite System) is now publicly-funded by EU and it's testing is advancing. The next video has more details.
http://international.findmespot.com/
Galileo GNSS (Global Navigation Satellite System) is now publicly-funded by EU and it's testing is advancing. The next video has more details.
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