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Compartimos un artículo publicado en el sitio NASASpaceFlight.com sobre la empresa estatal argentina ARSAT
September 21, 2015 by Alejandro G. Belluscio
When Ariane 5 flight VA226 launches on September 30, the orbital slot for the 81 West geostationary position will finally get its long-term dweller that it has been promised for over 17 years. Riding along with the Sky Muster satellite, ARSAT-2 is the second geostationary satellite designed and manufactured in Argentina (and all of Latin America).
The birth of a program:
ARSAT-2 is the younger twin of ARSAT-1. It is a near copy of the first Argentinean geosynchronous orbit satellite, with the only difference being the payload and associated structures.
The story begins with the separation of the Argentine military forces from the national space program in the early 1990s.
It was a requirement to occupy the single geostationary slot that was assigned by ITU to the country – the 71.8 West position – before the rights lapsed. Additionally, the ground station, as well as all operators, were to be Argentine.Given the dire economic situation of the country and the general disarray of the space program that was struggling to organize itself, the government auctioned the exclusive use of satellite Ku-band in the country.
The winning consortium formed Nahuelsat S.A., which leased the required satellites to keep hold of the orbital rights until it successfully launched the Nahuel 1A to the orbital position by early 1997.
By 1998, DirecTV wanted to enter the local market, since it was the country with the highest per capital cable television penetration in the world.
In exchange for that, Argentina gained the rights to a prime orbital real estate: the 81 West orbital slot.
Not only did it include both Ku and C band right, but instead of just allowing signals to Argentina and neighbors, it included all of the Americas from Alaska to Patagonia.
C band is usually used to distribute television channels among broadcasters, and Ku band small antennas are usually used for direct-to-home television like DirectTV.
Since Argentina is the biggest exporter of Spanish media content in the continent, it was a particularly attractive position for the country.
Also given that the slot goes right through the center of the continental USA – and it was acquired as a trade for allowing DirecTV to enter the television market in Argentina – it could potentially enable to tap the direct-to-home TV market of the USA.
Regrettably, Nahuelsat not only failed to launch the promised Nahuel 2 to the 81 West slot but also failed to order a replacement for the aging Nahuel 1A.
With the imminent failure of the only orbital asset, and without any actual willingness to invest in a replacement, after some negotiations the Nahuelsat stockholders accepted to transfer all assets and obligations to the newly created and government owned ARSAT.
The Geostationary Argentine Communications Satellite System:
Instead of ordering a couple of satellites from the international market – and thanks to the successful experience of the SAC-C and SAC-D – country executive powers decided that ARSAT should acquire the satellites from local companies.
The only real choice was INVAP S.E., a technology company that belongs to the Rio Negro Province and has craved a niche in the research nuclear reactor market and had also been building the national LEO satellites.
With the SAC-D, they had shown that they could work to the stringent NASA engineering standards.
The contract for the ARSAT-1 was thus signed by 2008. While INVAP was the prime contractor, the design rights would belong to ARSAT.
From its very conception by top executive officials, the ARSAT program was supposed to bring the country industrial base to the front of satellite development. This meant that ARSAT and INVAP funded CEATSA an environmental test center that could handle the stringent simulations and size requirements of GEO platforms.
While they did rely on foreign suppliers for some commodity elements, like propulsion engines, solar panels and on board computer hardware, over 50 percent of parts, and all design, qualification and testing was done locally.
Also, every single piece of software was written from scratch by Argentine industry, as was the ground control segment.
With this development, the country could control the specification, design, manufacturing, testing and operations of GEO satellites.
The ARSAT-2:
As the previous satellite based on the ARSAT-3K bus, it is a three ton spacecraft, weighting 2985kg at launch, with a bi-propellant capacity of 1,520 liters.
It has an Astrium S400 main engine, and sixteen S10 thrusters. The bare bus measures 1.8m x 2m x 2.9m and its final dimensions are 2.2m x 2.4m x 4.4m when fully equipped and stowed for launch. Its solar panels span 16.4m when deployed and generate 4.2kW at the end of life, of which 3.5kW are available to the payload.
The platform is three-axis stabilized and uses four reaction wheels, dual inertial measurement units, a fine sun sensor, a Selex star tracker and an infrared earth sensor for orbital maneuvering and determination.
While some commodity components like the thrusters, main composite cylinder or the main computer board were supplied by foreign contractors, over 50 percent of parts were manufactured in Argentina, as well as the whole design, integration and software.
Sophisticated modules like the ACE (the Attitude Control Electronics) and TCE (Thruster Control Electronics), the whole structures, and all software and algorithms were done by INVAP.
This was no small feat since it is the critical part of design that usually more heavily covered by dual-use technology transfer laws -like the American ITAR- and geosynchronous orbital maneuvering is just a small step from interplanetary.
Even the ground control station software and satellite control and telemetry system was built by Argentinean contractors.
This enables control of the whole technology stack of the satellite from production to control without foreign help. A critical step from a national security point of view.
This was also no small feat, with the ARSAT-1 requiring more then 1.3 million man-hours, more than 10km of cable, 1,031m² of carbon fiber composite and generating more than 11,500 design documents.
ARSAT-2’s communication payload was supplied by Thales of France. It consists of 20 Ku-Band transponders, sixteen of 36 Mhz and four of 72Mhz for total bandwidth 864Mhz (or 24 36Mhz equivalent transponders) with one 2m deployable and one 1.3m fixed Gregorian antenna.
The C-Band payload is composed of six transponders, four of 72Mhz and two of 88Mhz, for a total bandwidth of 464Mhz (practically thirteen 36Mhz equivalent transponders) using a single 1.6m deployable antenna.
It will cover all the Americas offering data services as well as television content distribution. This is a strategic asset since Argentina is the leader on broadcast content production for Latin America and ARSAT-2 will enable it to distribute it directly through all the continent.
While the payload was supplied as a whole subsystem by Thales Alenia, the integration even to the physical mating and integration with the bus, was done entirely by INVAP with the contractor just overseeing the procedure.
The ARSAT family future:
While originally the idea was to initially build and launch three satellite, ARSAT-1/2/3, the excellent technical results of the ARSAT-1/2 combo meant that there was no need to launch ARSAT-3 right behind the ARSAT-2.
Originally envisioned as a Ku-band and C-band satellite co-located with ARSAT-2 in the 81 West slot, later strategic consideration switched its mission to a Ka-band multi-spot satellite. Since this would require new slot rights negotiations within the ITU, the project was delayed a while.
Never to lose the chance of converting a delay in an opportunity, ARSAT has signed an agreement with the Ministry of Science and Technology to help to evolve the bus to the most modern technologies.
They are currently trading the ARSAT-3H and ARSAT-3E platforms for the satellites that will come after ARSAT-3 and ARSAT-4. The ARSAT-3H would be a new hybrid platform, that would use chemical propulsion for orbit rising, and electrical propulsion for station keeping. While still weighting around 3 tones, it would have 8.4kW of power at the end of its 15 years expected life, with 6.8kW available to the payload. It would offer a 60% increase in power at the same weight and with an extra cost of just 30%.
The ARSAT-3E would be a purely electrical design that would use the higher efficiency electric propulsion both for orbital maneuvering and station keeping. Purely solar electric satellites, like the Boeing 702SP platform, can usually halve the weight for a given payload power envelope when compared to a purely chemical propulsion system. The increased efficiency would be applied to weight and cost reduction while staying in the ARSAT-3H power envelope.
Being the clear leader in satellite design and manufacturing in Latin America was a huge national effort, and Argentina clearly believes in pushing it forward to the bleeding edge of the world technology.
