Author Topic: Galileo Deployment  (Read 83442 times)

Online eeergo

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Offline GWR64

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Re: Galileo Deployment
« Reply #141 on: 03/28/2023 06:28 pm »
Oh oh   :(
[...]
one of several

Testing testing...

https://mobile.twitter.com/GalileoSats/status/1640282783770636289

GSAT0210/E01 is still unusable and was unusable before this test.
The clock jumps on GSAT0210 have nothing to do with this test, I think.
« Last Edit: 03/28/2023 08:01 pm by GWR64 »

Offline GWR64

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Re: Galileo Deployment
« Reply #142 on: 04/02/2023 09:31 am »
Quote
NOTICE ADVISORY TO GALILEO USERS (NAGU) 2023023
DATE GENERATED (UTC): 2023-03-29 17:50

NAGU TYPE: USABLE
NAGU NUMBER: 2023023
NAGU SUBJECT: USABLE AS FROM 2023-03-29
NAGU REFERENCED TO: 2023019
START DATE EVENT (UTC): 2023-03-29 16:18
END DATE EVENT (UTC): N/A
SATELLITE AFFECTED: GSAT0210
SPACE VEHICLE ID: 01
SIGNAL(S) AFFECTED: ALL

EVENT DESCRIPTION: GALILEO SATELLITE GSAT0210 (ALL SIGNALS) IS USABLE SINCE/AS OF 2023-03-29 BEGINNING 16:18 UTC. PAYLOAD ON RAFS CLOCK. GALILEO SATELLITE GSAT0210 (ALL SIGNALS) WAS UNAVAILABLE FROM 2023-03-23 BEGINNING 17:37 UTC.

GSAT 0210 is usable again. As before the last break, with a rubidium atomic clock (RAFS).
It is not clear whether both rubidium clocks are still working.
It will probably be 2 years or more before a replacement will be usable. Long time.
« Last Edit: 04/02/2023 12:11 pm by GWR64 »

Offline jpo234

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Re: Galileo Deployment
« Reply #143 on: 04/18/2023 12:30 pm »
Politico article about Galileo launches on Falcon 9 and/or Vulcan: EU turns to Elon Musk to replace stalled French rocket
Quote
The Commission reckons only SpaceX's Falcon 9 heavy launcher and United Launch Alliance's Vulcan system are up to the job of sending the EU's new geo-navigation Galileo satellites — which weigh around 700 kilograms each — into orbit.
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Offline GWR64

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Re: Galileo Deployment
« Reply #144 on: 04/30/2023 10:22 am »
Damned! GSAT0210 off again

Quote
NOTICE ADVISORY TO GALILEO USERS (NAGU) 2023032
DATE GENERATED (UTC): 2023-04-30 08:30

NAGU TYPE: UNP_UNUFN
NAGU NUMBER: 2023032
NAGU SUBJECT: UNAVAILABLE FROM 2023-04-30 UNTIL FURTHER NOTICE
NAGU REFERENCED TO: N/A
START DATE EVENT (UTC): 2023-04-30 00:52
END DATE EVENT (UTC): N/A
SATELLITE AFFECTED: GSAT0210
SPACE VEHICLE ID: 01
SIGNAL(S) AFFECTED: ALL

EVENT DESCRIPTION: GALILEO SATELLITE GSAT0210 (ALL SIGNALS) IS UNAVAILABLE SINCE 2023-04-30 BEGINNING 00:52 UTC UNTIL FURTHER NOTICE.
https://www.gsc-europa.eu/system-service-status/constellation-information

Politico article about Galileo launches on Falcon 9 and/or Vulcan: EU turns to Elon Musk to replace stalled French rocket
Quote
The Commission reckons only SpaceX's Falcon 9 heavy launcher and United Launch Alliance's Vulcan system are up to the job of sending the EU's new geo-navigation Galileo satellites — which weigh around 700 kilograms each — into orbit.

After the Ariane 6 status update in October 2022 and the statement from Arianespace CEO Stéphane Israël
(in connection with the delay): "... no issue..." the EU should have reacted.
Even if it was about the lack of overlap between Ariane 5 and 6, it also concerns the replacement for the Soyuz.
« Last Edit: 04/30/2023 10:32 am by GWR64 »

Offline GWR64

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Re: Galileo Deployment
« Reply #145 on: 05/18/2023 08:25 am »
Politico article about Galileo launches on Falcon 9 and/or Vulcan: EU turns to Elon Musk to replace stalled French rocket
Quote
The Commission reckons only SpaceX's Falcon 9 heavy launcher and United Launch Alliance's Vulcan system are up to the job of sending the EU's new geo-navigation Galileo satellites — which weigh around 700 kilograms each — into orbit.

Checked this on the Nasa Launch Vehicle Performance website. However, I do not know exactly which C3 energy the
Galileo orbit corresponds. So I can only guess.
The Falcon Heavy (Recovery) and the Vulcan VC2 come into question for Galileo launches.
Both could probably lift 4 Galileo-satellites + dispenser (~3300 kg) into the intended orbit. In terms of performance, they are close to each other.
For Falcon-9 ASDS or expendable, I can't find data in this range.
Surprising to me, an Atlas V 401 could possibly have launched 2 satellites + dispenser, while a Vulcan VC0 certainly cannot.
Other alternatives: H-2A or H-3 obviously are not available.
The Ariane-5 ES was discontinued too early.
« Last Edit: 05/18/2023 09:27 am by GWR64 »

Online LouScheffer

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Re: Galileo Deployment
« Reply #146 on: 05/20/2023 10:53 pm »
Politico article about Galileo launches on Falcon 9 and/or Vulcan: EU turns to Elon Musk to replace stalled French rocket
Quote
The Commission reckons only SpaceX's Falcon 9 heavy launcher and United Launch Alliance's Vulcan system are up to the job of sending the EU's new geo-navigation Galileo satellites — which weigh around 700 kilograms each — into orbit.
Checked this on the Nasa Launch Vehicle Performance website. However, I do not know exactly which C3 energy the
Galileo orbit corresponds. So I can only guess.
The Falcon Heavy (Recovery) and the Vulcan VC2 come into question for Galileo launches.
Both could probably lift 4 Galileo-satellites + dispenser (~3300 kg) into the intended orbit. In terms of performance, they are close to each other.
For Falcon-9 ASDS or expendable, I can't find data in this range.
Wikipedia lists the orbit as circular at 23222 km altitude.  To reach this apogee from LEO, you need to add about 2185 m/s.  When you arive at the top, you are going 2212 m/s, and need to speed up to 3670 m/s, so need to add 1458 m/s.   So from LEO, you need to add about 2185+1458 m/s, or about 3643 m/s total.  This same total, all applied at LEO, would lead to escape at about C3 = 9 km^2/sec^2.

According the the NASA web site, the F9 can lift 2325 kg to this orbit.  (2-3 satellites).  They don't give a figure for fully expendable, but guesses make it look like about 3700 kg, so 4 satellites.  VC2 can lift 4865 kg (6 satellites) and FH recovery can lift  5275 kg (6-7 satellites).

EDIT:  This is not correct for Galileo orbits at 56 degrees.  For a generic C3=9 mission the inclination does not matter, as long as abs(DLA) <= launch latitude (which is true for almost all escape missions, when launching from USA sites).    But for a 56 degree, non-escape mission, it does matter.  Here's a guess how much:

To reach an orbit with an inclination of 56 degrees from the cape, you need to launch at 58.5 degrees from the equator (or a launch azimuth of 31.5 degrees).  At this azimuth, instead of the 408 m/s boost from earth rotation, you only get 408*cos(58.5) = 213 m/s, or 194 m/s less.  This 194 m/s must be made up elsewhere, so the total dv to 3837 m/s, which when applied from LEO corresponds to a C3 = 13.6.  This gives 4360 kg for VC-2, and 4650 for FH with recovery.

However, these will still be optimistic if launching from the Cape.  The cape allows azimuths from 35-120 degrees, but this orbit wants 31.5.  So a dogleg will be needed as well, further limiting performance.  These were also needed on the GPS mission with similar orbits.  I don't have a good estimate of how much performance this costs.

« Last Edit: 05/21/2023 05:58 pm by LouScheffer »

Offline GWR64

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Re: Galileo Deployment
« Reply #147 on: 05/21/2023 03:36 am »
Politico article about Galileo launches on Falcon 9 and/or Vulcan: EU turns to Elon Musk to replace stalled French rocket
Quote
The Commission reckons only SpaceX's Falcon 9 heavy launcher and United Launch Alliance's Vulcan system are up to the job of sending the EU's new geo-navigation Galileo satellites — which weigh around 700 kilograms each — into orbit.
Checked this on the Nasa Launch Vehicle Performance website. However, I do not know exactly which C3 energy the
Galileo orbit corresponds. So I can only guess.
The Falcon Heavy (Recovery) and the Vulcan VC2 come into question for Galileo launches.
Both could probably lift 4 Galileo-satellites + dispenser (~3300 kg) into the intended orbit. In terms of performance, they are close to each other.
For Falcon-9 ASDS or expendable, I can't find data in this range.
Wikipedia lists the orbit as circular at 23222 km altitude.  To reach this apogee from LEO, you need to add about 2185 m/s.  When you arive at the top, you are going 2212 m/s, and need to speed up to 3670 m/s, so need to add 1458 m/s.   So from LEO, you need to add about 2185+1458 m/s, or about 3643 m/s total.  This same total, all applied at LEO, would lead to escape at about C3 = 9 km^2/sec^2.

According the the NASA web site, the F9 can lift 2325 kg to this orbit.  (2-3 satellites).  They don't give a figure for fully expendable, but guesses make it look like about 3700 kg, so 4 satellites.  VC2 can lift 4865 kg (6 satellites) and FH recovery can lift  5275 kg (6-7 satellites).

The ULA states 3900 kg for VC2 for MEO (Medium Earth Orbit) = 20,368 km circular at 55 deg (GPS)
So I assumed the C3 value is higher.
https://www.ulalaunch.com/rockets/vulcan-centaur

Online LouScheffer

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Re: Galileo Deployment
« Reply #148 on: 05/21/2023 05:39 pm »
The ULA states 3900 kg for VC2 for MEO (Medium Earth Orbit) = 20,368 km circular at 55 deg (GPS)
So I assumed the C3 value is higher.
https://www.ulalaunch.com/rockets/vulcan-centaur
Oops - the calculation I did was to raise from an LEO orbit to a Galileo orbit of the same inclination.  For a generic C3=9 mission the inclination does not matter, as long as abs(DLA) <= launch latitude (which is true for almost all escape missions, when launching from USA sites).    But for a 56 degree, non-escape mission, it does matter.  That means my estimates above will be optimistic.  I'm adjusting them.

EDIT: revised estimate is C3 = 13.6 (see above).  But this is still somewhat optimistic if launched from the Cape, as a dogleg trajectory will be needed to hit this inclination.
« Last Edit: 05/21/2023 05:56 pm by LouScheffer »

Offline GWR64

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Re: Galileo Deployment
« Reply #149 on: 06/09/2023 10:16 am »
GSAT0210 has been out of service for over a month now, I'm afraid that's it.
After GSAT0204, that would be the second FOC satellite that obviously no longer has an exact atomic clock.
This is where the hardware error in the rubidium clocks on the FOC satellites GSAT0201 to GSAT0214 (worst case) takes revenge.
The IOV satellites had problems early on with the hydrogen maser, but 3 of them still work with rubidium atomic clocks. The failure of GSAT0104 had another reason.
So one satellite each is missing in plane A and C.
The progress on Ariane 6 is very slow. If the first launch takes place in H1 2024,
there are probably max 1-2 more launches in 2024. So at most one for Galileo.
A Falcon 9 ASDS launch with 2 satellites is tight. Expendable it works, I think.
Whether a launch with 4 satellites is desired, I don't know. Maybe in plane C. More than 4 makes no sense.
The two options are above.
Many thanks to @LouScheffer for the excellent analysis.

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