15 June 2012

Green light to fuel MSG-3

Though the investigations related to Intelsat-19 solar array anomaly may continue, the fuelling of our co-passenger has effectively started on 15/06/2012 early morning at EPCU S5A.
This point was one of the prerequisites to close out the MSG-3 Pre-fuelling Review. As a consequence, authorisation has been given to fuel MSG-3. The fuelling preparation will start tomorrow, and the first drop of MON propellant should be in the tank as from Monday 18/06/2012.
This decision, expected for three weeks now, was very welcome by all teams here at CSG.
This date (15/06/2012) is an important milestone for both payloads and also a step forward in this campaign for a launch scheduled on 05/07/2012.
Here above, MSG-3 in EPCU S5B on the fuel stand as it looks since its transfer from S5C on 11/06/2012. On both sides, the "boas" blow air to cool the two batteries.
Last but not least, a warm welcome to all members of the Thales fuelling team who just reached Kourou!

14 June 2012

At the border again: Saint Georges-Oiapoque

Driving 200 kilometers southwards on the RN2 road from Cayenne will lead you to Saint Georges a border village with Brazil set on the Oyapock river. Note that the asphalted portion of the RN2 road between Regina and Saint Georges was completed in 2004.

Saint Georges is a quiet typical Guyenese small village where the connection with Oiapoque (Brazil) is made with pirogues commuting on both sides of the Oyapock river. In 2011 a huge cable-stayed bridge connecting the two cities was built. The road on the Brazilian side is not yet completed therefore the bridge is not open yet to traffic. This is planned in 2013 (?). Therefore, a kind of cathedral in the desert at the moment...
Before having a glance on Saint Georges, the short history of the border line between French Guiana and Brazil is worth to remind. This argued border was initially set by the Utrecht Treaty in 1713.
In the Contesté franco-brésilien, the following sentence of the 1713 treaty was the causing the issue:
"Que la navigation de l'Amazone, ainsi que les deux rives du fleuve, appartiendront au Portugal, et que la rivière de Japoc ou Vincent Pinson servira de limite aux deux colonies."
It took roughly 200 years to understand what the diplomats at the time meant with spelling of the word  "Japoc". For Brazilians (who became independent in 1822)  this word was clearly designating the Oiapoque river but for the French the Araguary river (part of the Japoc region?). A Swiss arbitration in 1900 gave right to Brazil on their interpretation of the treaty adding a surface corresponding to half the surface of France to the Northern part of their territory!
En passant, the history of the western border (between French Guiana and Suriname) is not more glorious for France. There is even still an area situated on the high Maroni river which is under argument...For further reading on the topic click here...
But let's come back to Saint Georges. The most active part of the city is organised around a large square sitting, on one edge, along the Oyapock river. On the opposite side of the river, a refreshed town hall can be observed, the rest of the perimeter being filled with small restaurants, a grocery and some usual houses. In the middle of this square, a memorial sadly reminds the names of the local citizens who lost there life in the first world war (1914-1918).
A closer view on it unveils the long list of people who were sent to remote european battle fields in 1914 somewhere between other borders: those of France Belgium and Germany. They likely had no clue where it was before leaving French Guyana and what were the reasons of this conflict. Considering the small size of the village and the amount of human losses, it easy to understand the importance of the 1914-1918 tragedy.
Today, it should be reminded all the time that the period of ca 70 years of peace and growth that benefited  Europe since 1945 was due to the development of the European Union process between the the old fighting nations. Contemplating this monument, it is easy to understand why this process should be pursued and consolidated today to face the challenges of the new surfacing world.
The town hall can be easily be identified by its blue and yellow colours on the facade. The city blazon with the bow in the left corner can be noticed. A slogan beneath the city blazon "M'arc boute  POC à POC" reflects an onomatopoeia, related to the noise of a bow when it is arched. The presence of a  Jaguar fighting with an indigenous man on the same blazon is peculiar enough to be mentioned as well.
On the right hand side of the square (when looking at the town hall) stands a small restaurant with the lovely name of "Chez Modestine". The restaurant terrace faces the square. From there, you can observe  taxis commuting on the river.
For literature lovers, Modestine refers to Robert Louis Stevenson, a famous Scottish (travel) writer. If everybody knows the Treasure Island, few people only knows Travels with a Donkey in the Cévennes. Modestine was the name of this unpredictable but lovely donkey who brought to Stevenson's trip some unexpected surprises... At the restaurant, no donkey, just a nice scarlett macaw on the signboard.
Before starting the river crossing to Brazil, don't miss the only "monument" of the village: the church. It is at this very place, that "donkey's ears" ago, deported prisoners discovered in the soil some Dutch coins representing Saint Georges while they were building the church. This may be the explanation of the village's name.
Eventually it's time to embark to Oiapoque (Portugese spelling) i.e. the Brazilian border city on the other side of the river. At Saint Georges pier, a "taxi"driver is almost waiting for you round the clock. The transfer will last 15 minutes and cost 5 euro for a single ticket per person. Click here to get the journey impressions.
On the other side, this is the Oiapoque "harbor" as you will discover it:
It is not sure that the vast majority of Rio de Janiero or other Brazilian citizens from large cities would recognise Brazil at this very place or even precisely locate this nice city on the map. Anyway, welcome to Brazil!
A warning notice plate written in Portuguese and something between French and Creole languages tells you about risks across the border. For sure this represents a promising discovery as important as the Rosetta Stone for  archaeologists of the next millennium :-)
In case you get homesick, you still have a chance to see the French Guyana bank from the Brazilian side. Then you will realise two things:
First, that the landscape on the Oyapock river and the Saint-Georges - Oiapoque bridge on the background is absolutely gorgeous. 
Secondly, that the river is not a real border but on the contrary a link between the peoples.

12 June 2012

The Oyapock connection

The Oyapock river is the border between Brazil (Amapá state) and French Guiana. This rivers which penetrates deeply through the Amazon rain forest is also the unique natural route used daily by river taxis to connect indigenous populations together over a distance longer than hundreds miles. The snag is that the Oyapock river is not flat all along the trip...
Few miles after Saint Georges or Oiapoque cities, large rocks surface, creating rapids and water stream. This place, called Saut Maripa (litterally Maripa Jump), is extremely picturesque but not a real "path" that can be easily crossed by a pirogue.
Whatever your plans are, to make an excursion from the bank to observe this unique site, or to travel upstream to Camopi, you do need to disembark and leave your pirogue on the bottom side of  the falls.
Few meters higher, an unexpected show can be observed. Roughly hundred meters further upstream, a group of people are just waiting with their wrapped luggage standing on a rock in the middle of the river. 
Not very much later, a new pirogue arrives from the other side of the river, making some large curves to avoid dangerous rocks, in order to finally reach this isolated group of travellers....
Crew and freight are carefully transferred from the bank to the pirogue for the next leg of the trip.
Once everything is safely loaded, this heavy carriage slowly leaves upstream  this splendid location up to the next "jump".
How many time this sequence is repeated along the trip on the Oyapock river? How long does it take to reach Camopi?  Four hours or more? May be this is not the right question to ask because there is no other alternative. What is sure is that these river taxis are extremely skilled to maneuver in this unfriendly area and, on the top of that, quite well organised considering the number of necessary connections to get a smooth trip all along the Oyapock river.

11 June 2012

MSG-3 new launch date

According to a recent Arianespace press release, MSG-3 launch date is now rescheduled* for the night of 5th to 6th of July 2012.
Launch window starting
  • from 06:36 pm to 7:05 pm (Kourou time), Thursday 5th July
  • from 11:36 pm to 12:05 am in Paris, Darmstadt, Noordwijk, on the night of Thursday 5th to Friday 6th July. 
Click here for the full press release.

* Initially the VA 207 launch was scheduled on 19th of June 2012. Mid May, due to MSG-3 co-passenger need for additional testing, a first rescheduling date was planned on 29/06. The additional Intelsat-19 Solar array investigations as from 31/05 killed this option.

Updates:
  • 12/06/2012: Click here to read the ESA announcement of the launch date reset.
  • 12/06/2012: Click here to read the EUMETSAT announcement of the launch date reset

On the move again

If you had popped up today at the EPCU you would have got the impression that something has changed. In contrast with the last two weeks of stand-by, everything was active as in the first days of the campaign. First, at the usual daily meeting you would have noticed few colleagues back from Cannes and Noordwijk (welcome to all of them) and second a glance towards the S5C clean room from the visitor gallery would have shown you that MSG-3 had disappeared! What happened?  this deserves at least few words of explanations.
So after two weeks of baby sitting, there is now enough information from our co-passenger to decide  moving step by step MSG-3 to the fuelling phase of the campaign. This also means that an official launch date is being consolidated and should be released by the official authorities, Arianespace, Eumetsat and ESA pretty soon.
In line with this approach, it was decided to move on 11/06 the spacecraft from its initial S5C location since the campaign started  to the "gas station" place known here as S5B. For a better understanding of this activity and the following text and pictures, we recommend, for those of our dear readers who wish to refresh their mind, to read the two past messages: Working at EPCU (dated 20/04) and Introducing S5B (dated 12/05).
Therefore, no big surprise that MSG-3 disappeared from S5C, it stands now safely as from today on the fuelling stand in S5B.
Pictures below reflect the various steps of this sequence remarkably performed by Thales with the support of the CSG staff.

07 June 2012

BAF Acceptance successful

Despite few remaining uncertainties, MSG-3 launch campaign carries on with enthusiasm. Today, another successful milestone was achieved: the BAF (Batiment d’Assemblage final/Final Assembly building) acceptance.
This blind tower is somehow mysterious as already explained in the last part of the message (from BIL to BAF). No pictures from inside can be published, and one will have unfortunately to read further this message for getting the details of what happened today. As a compensation, a cropped picture of the acceptance team was authorised to be released.
From left to right: Alina (Arianespace), Francois (ESA), Jean (Thales), Jean-Claude (Eumetsat) and Cyril (ESA)
It is always impressive to visit the BAF due to the close presence of the Ariane 5 rocket inside. Getting to the upper platforms with the lift gives an impressive view on the solid rocket boosters and the main tank. Seen so closely from the windows of the moving lift, the rocket seems to take off: fortunately this is just a visual illusion :-)
For memory, the Ariane 5 VA207 will be a double launch where Echostar-17 will get the top position and MSG-3 the lower one inside the fairing. Mating and encapsulation of these two spacecrafts will take place in this dedicated building. Most of the tasks are made by the Ariane space personnel. However, a limited number of MSG-3 team members will have to be present for specific operations.
The purpose of today acceptance was to check in advance that areas to be used by MSG-3 inside the BAF facility are ready and all specifications announced by Arianespace are properly implemented.
MSG-3 team inspected three specific areas: 
  • The airlock on the groung floor, i.e. the area where MSG-3 will arrive at BAF
  • The two platforms situated on the top of the rocket where MSG-3 will be mated on the launcher: i.e. PFEI and PFES located in the upper part of the BAF
  • The COTE room at the bottom of the Launch table where the equipment will be connected on one side with the Spacecraft and on the other to the control room at EPCU S5C  (COTE stands for Check Out Test Equipment)
Just for curiosity, a bird cage was found in a corner close to one of the elevated platforms (at the upper of the tower): what was it used for?
The purpose is very simple: it is a trap. There is in fact always a risk to have birds entering the building between opening and closing of the external doors. This cage, full of food, will just permit to catch them before, trapped inside the fairing, they can get a free ticket to space and/or create some other incidents. For the same reasons, insects are not welcome in this area. Several fly catchers (with UV lamps) were placed around and proved to be rather efficient. For rodents, we did not find any visible counter measures. Do mice simply suffer from vertigo and therefore give up adventuring on the top of the rocket?
Whatever the answer is, the acceptance was concluded fully successful for all other technical aspects. This event was felt by the team as a positive achievement and a good sign for the steps to come.

06 June 2012

MSG for dummies :-)

Note: This message is published as a living list of naive questions. It is of course not exhaustive of the MSG design.
A special thanks to Jean-Claude, Rolf and Francois for their support.
I - MSG PLATFORM DESIGN
What does "platform" means?
A spacecraft is normally made of two main elements; The platform which comprises all the support subsystems and the payload (SEVIRI and GERB for MSG) that will provide the mission data.
The MSG platform design comprises the following subsystems:
  • Data Handling Subsystem (DHSS) + Software (SW)
  • Electrical power Subsystem (EPS): 8 Solar Arrays, 2 Batteries, Power conditioning and distribution Units (PCU and PDU), and Pyrothechnic Release Unit (PRU)
  • Attitude and Orbit Control Subsystem (AOCS). This comprises Control Electronic units (AOCE), Sun and Earth Sensor Units (SSU and ESU) and the passive nutation Dampers. The AOCS directly commands the UPS.
  • Unified propulsion System (UPS). The UPS is a Bi-propellant system including the Liquid Apogee Motors (LAMs), the Reaction Control thrusters (RCTs), the pressurant and propellant tanks, all necessary valves, filters, pressure regulators and transducers and the Ultrasonic Gauge sensors (UGS)
  • The Telemetry, Tracking and Command Subsystem (TT & C). This is supported by the Mission Communication Package (MCP) with all antennas and electronic units.
  • The Thermal Control Subsystem (TCS), mainly insulation blanket (MLI) and optical sun reflectors (OSR). 
  • The Structure Subsystem, mechanisms and Pyrotechnic devices
Where can I find a good description of the MSG-3 spacecraft platform functions?
About propulsion: to be filled later

Why MSG has a cylindrical shape?
Because the spacecraft is designed to rotate around its vertical axis during its mission at an angular speed of 100 rounds per minutes. The spinning increases the moment of inertia and therefore the gyroscopic stabilisation. It simplifies the the design of the attitude control sub-system compared to a 3 axis stabilised spacecrafts.

Why MSG is spinning and what are the general benefits of spinning satellites?
MSG rotation is 100 round per minute around its vertical inertial axis. It belongs then to the spin-stabilised satellite family. The main benefit is the attitude stabilisation by mean of the gyroscopic effect which makes the design of the attitude control much more simpler than a 3 axis stabilised spacecraft. The attitude stability is an essential parameter to get a sharp image by a “camera” at 36.000kms distance from Earth. At the time MSG programme was started in the seventies, the 3 axis technology was not able to meet the mission requirements. This new technology will appear on the third generation of Meteosat spacecraft (MTG) by end of the decade.

Why the SEVIRI solar array is slightly longer than the other ones?
There are eight solar panels mounted on MSG: one SEVIRI and seven "normal" panels. It is true that the SEVIRI Solar array (see above) is slightly bigger in size but the solar array surface covered by solar cells is the same for each panel. This oversize is made to compensate, with additional solar cells, the large SEVIRI aperture. As MSG is spinning the electrical current to be generated by the solar array in space should be the same for each solar array to prevent variations during the rotation.


What is the use of Earth and Sun Sensor Units  (ESU and SSU)  mounted on MSG?
 The Earth and Sun sensor units allow:
  1. to determine the spacecraft attitude when  S/C, sun and earth  are not to close from  alignment (i.e. angle  between S/C earth direction and S/C sun direction  is above ca  15 deg and below ca  165 deg) 
  2.   to measure the spacecraft spin rate (function done by the sun sensor unit only) 
  3.   to elaborate a reference pulse used  a)  for synchronising the image taking by SEVIRI and GERB with the S/C rotation (ie to determine when the instrument is exactly facing the Earth), b) for synchronising the radial thrusters in order to deliver a radial force in a given direction (as the S/C is permanently spun) 
  4. to synchronise the electronically despun antenna  (which counteract the S/C spin in order to ensure permanent pointing of this antenna towards the earth.
What is a despun antenna?
An Electronically Despun Antenna (EDA) is mounted on the top of the cylindrical MSG-3 spacecraft. The EDA purpose is to have the antenna continuously pointing at Earth whilst the spacecraft is rotating.

How MSG communicates with Earth?
This function is performed by the Mission Communication Package.
to be filled later

What are the propellants used on board MSG-3?
MSG propulsion is achieved by a classical bi-propellant system, i.e. the combustion of two components: a liquid fuel with a liquid oxidizer.
MSG system uses Monomethylhydrazine (MMH) as liquid fuel and Mixed Oxides of Nitrogen (MON) as liquid oxidizer.

02 June 2012

Breaking news

A press article dated Saturday June 2nd, reports a possible Solar Array deployment issue on a telecom satellite launched on 31/05/2012. This spacecraft is manufactured by the same company as the MSG-3 co-passenger for the next Ariane 5 flight.

Click here to get the full article.

Updates
  • 5/6/2102: It is confirmed that the on-going failure investigations will impact the MSG-3 launch campaign schedule.
  • 6/6/2012: MSG-3 keeps in stand-by till fuelling date of MSG-3 co-passenger is confirmed. 
  • 7/6/2012: a new press article provides some additional information on the failure investigation. 
  • 8/6/2012: Good news; green light has been given to fuel. Exact date to break stand-by has now to be determined in an overall updated schedule.