The flight segment of the SAOCOM 1A and SAOCOM 1B satellites was reviewed in San Carlos de Bariloche. This constellation of Argentine earth observation satellites was developed by the Argentine National Space Activities Commission (CONAE, in Spanish), dependent on the Ministry of Science, Technology and Productive Innovation, together with INVAP S.E. (an Argentine state-owned applied research company) as the main contractor.
The SAOCOM 1A and SAOCOM 1B are two identical satellites carrying a Synthetic Aperture Radar (SAR) as their main instrument for remote sensing through microwaves. The earth observation through radar involves complex technological elements which have been developed in the country for the first time in the context of the National Space Program of the CONAE. The aim has been to meet the space information requirements of several sectors, such as those working in the economic-productive, scientific, educational and emergency management fields, as well as for new health applications.
The SAOCOM series is comprised by two constellations, SAOCOM 1 and SAOCOM 2, made up of two satellites each: SAOCOM 1A and SAOCOM 1B, and SAOCOM 2A and SAOCOM 2B. The constellation 1 satellites, which will be the first to be put into orbit, are now under construction in our country by the national scientific and technological system together with Argentine technological companies. The SAOCOM 1A will be launched in 2017 and the SAOCOM 1B in 2018. Both have the same qualities as regards design, functionality and effectiveness, so that they are being built simultaneously in order to have two identical satellites working as part of the same constellation. In this way, the image supply capacity is increased, and the time needed to reobserve (revisit) the interest areas is reduced. The observational capacity of the SAOCOM satellites is a major contribution to monitor variable phenomena over time, such as the growth and evolution of agricultural crops, and to manage emergencies such as floods.
Review approved and praised
The new reviewing phase of the SAOCOM constellation development took place in San Carlos de Bariloche from March 30 to April 1 at INVAP’s facilities. The company is the main contractor in building the service platform. The Evaluation Board included experts from the European Space Agency (ESA), the NASA, the Canadian Space Agency (CSA) and the Italian Space Agency (ASI, in Italian) together with experienced professionals of the CONAE, who are leading representatives of other projects.
During three days, every aspect related to the evaluation and production of each satellite subsystem was reviewed. Attention was focused on the service platform and the SAR instrument, and particularly on the central electronics and the SAR antenna, as well as on the manufacturing plan and the task schedule. Besides, the tests results of all trials of the evaluating models (structural, engineering and thermal model of the SAR antenna) were displayed and reviewed. With this procedure, each model is tested under the real environmental conditions it will be exposed to during the launching and while in space. The testing process will finish with the SAOCOM 1A satellite environmental test, expected to be done by the end of the year.
The review was approved and the significant progress achieved was praised. Therefore, the process of starting the assemblage of both satellites, SAOCOM 1A and SAOCOM 1B, was given green light. Reviewers will present a report with their suggestions to benefit the mission. Getting through the reviewing phase means that the main elements of the satellite platform are adequate and suited to the final integration of all parts of the service platform to bring the satellite to completion, a task that will require a tight work schedule.
The Review Board of the ASI, CONAE, CSA, ESA and NASA visited the room where the SAOCOM 1A and SAOCOM 1B satellites were assembled in San Carlos de Bariloche.
Description of the SAOCOM mission, its capabilities and applications
Each SAOCOM satellite has as its main instrument a polarimetric Synthetic Aperture Radar (SAR), which operates in the range of the L-band microwaves, a band of particular interest to determine the environment biogeophysical parameters.
The radar sensors are able to capture data during daytime or nighttime, since they carry their own energy source on board to illuminate the earth’s surface. Thus, they do not depend on sunlight to capture the images. Radars have a remarkable capability to obtain images even through the clouds since the frequency used by the microwaves signal goes through them. Therefore, contrary to optical instruments, radars are able to capture data in any meteorological condition whatsoever.
The SAOCOM mission’s main goal is to support agriculture and hydrology through measurements determining soil moisture values. Another goal is to know better the topography of the earth. To achieve this, the satellite platform and the SAR must comply with the strictest requirements. As the mission aims to meet several space information demands in different areas, such as environmental issues, cartography, territorial organization, mining, geology, oceanography, health and, essentially, emergency management, it is a real technological challenge.
Apart from the soil moisture map and its derivatives, that are a great contribution to agriculture and hydrology, other products are also obtained, such as maps of water bodies, of deforestation and burned areas, crop classification, surface run off coefficients, urban sprawl, hydrocarbon spills, vessel detection, alternative routes facilitating navigation in ice-covered sea areas, dumping grounds and soil deformation.
As regards topography, the satellites will allow to measure ground displacements and landslides caused by earthquakes and even those produced as a result of human activity, such as oil extraction, excessive building construction, water extraction, subway construction and the generation of digital elevation models, among others.
Agriculture and emergency management applications
In compliance with the aim of supporting agriculture and hydrology, the SAOCOM mission will provide soil moisture maps of a vast area comprising the provinces of Buenos Aires, Córdoba, Entre Ríos, La Pampa and Santa Fe. It will gradually include the rest of the provinces in its following stages.
To achieve this, three applications, which are considered strategic due to its great socio-economic impact, are being developed and implemented at operational level. Two of them are intended for agricultural purposes and have been developed by the CONAE together with the National Institute of Agricultural Technology (INTA, in Spanish). The third one is aimed at hydrology and has been developed by the CONAE and the National Institute of Water (INA, in Spanish).
The agricultural and hydrology developments will help agricultural producers in:
1. Making decisions on sowing, fertilization and irrigation of crops such as soybean, corn, wheat and sunflower, in order to optimize the use of fertilizers and the estimation of yields, among other results.
2. The use of agrochemicals (crop-dusting) to control crop diseases, particularly to prevent fusariosis in the ear of wheat.
3. Risk management and control of hydrological emergencies, improving the hydrological modeling and forecasting capability to minimize the economic losses caused by floods.
Besides, thanks to the information gathered under particular observational conditions, specially useful tools may be produced to measure, for instance, the topography and detect earth’s crust deformation caused by volcanic activity or earthquakes anywhere in the world.
This mission is a major contribution to emergency management since both SAOCOM 1 constellation satellites will be part of the Italian-Argentine System of Satellites for Emergency Management (SIASGE, in Spanish), the first system worldwide specifically designed to prevent, monitor, mitigate and assess natural disasters. The SIASGE includes the Argentine SAOCOM 1A and SAOCOM 1B satellites, and the COSMO-SkyMed (a constellation of four satellites) developed by the ASI. The SIASGE first started with the four satellites of the COSMO-SkyMed constellation, now in orbit and in operation, and it will be fully implemented with the arrival of the SAOCOM 1B.
The four Italian satellites of the COSMO-SkyMed constellation monitor the earth through X-band radars, while both SAOCOM satellites do it through L-band radars. Hence the combination of these two types of radars will allow to gather relevant and accurate information for a large number of uses. The dual information channel increases the individual capabilities of each constellation since it is collected from different layers of the surface depending on its characteristics. The X-band provides information about the surface exposed to the radar pulses, whereas the L-band penetrates through the surface down to 2 m deep (in barren land). Therefore, the integration of both bands (X+L) shows highly complex structures and situations, which are impossible to detect by using only one of them. Furthermore, the six satellites are able to capture from the space images anywhere on the planet every 12 hours, which is particularly useful in case of emergencies.
Main Application Areas of the SAOCOM Mission Agricultural, fishing and forestry activities:
It will provide information for several tasks, variables and processes, such as cultivated forests’ surveying and monitoring, forest species composition, land use and land cover changes over time, fishing resources and exploitation, control of agricultural areas, harvest assessment, soil fertility and moisture conditions prior to sowing, control of weeds, pests, insects and fungal infections, etc.
Weather, hydrology and oceanography: Follow-up of climatic and hydrological changes in the whole Argentine territory and oceanographic studies of the Southern Atlantic and the Antarctic Seas. Besides, it will be useful for the quantification and follow-up of related critical parameters, such as water supply and soil moisture, its use to support agricultural activities, and studies on seas and coasts for scientific purposes to support navigation, port traffic and transportation activities.
Emergency management: Practices to be implemented at all stages, such as early warning systems, forward planning, preparation and forecast, response and assistance, and recovery and reconstruction. All these stages demand large input of information. In areas such as telecommunications, earth observation, meteorology and global positioning, space technology plays an important role in the information input, which together with other relevant georeferenced data (Geographic Information Systems, SIG in Spanish) help to create hazard maps and identify disaster-affected areas.
Environmental and natural resources monitoring: It will provide information for surveying the release and concentration of greenhouse gases (GEI, in Spanish) and for studies on the ozone layer change at global regional and national levels. It also includes surveying environmental information useful for the surveillance and follow-up of land and sea resources exploitation, not only to scientific ends but also to guarantee sustainability and avoid devastation.
Cartography, geology and mining: It covers remote sensing and relevant information processing for geological studies and its use in mining explorations and oil and gas exploitations. It also covers studies on oil and gas pipeline building and other similar infrastructure works, such as laying high-voltage lines, road and railways outlining, and large hydraulic works to drain large masses of water. It will also provide useful information to cartography activities.
Health: There are three large areas in which space technology can help to solve human health-related problems: telemedicine and clinical health care at a distance, public health emergencies related to natural disasters or man-made accidents, and landscape epidemiology. In the latter case, the SAOCOM mission will provide information complemented by field data to create predictive models on human diseases related to the environment, such as dengue, Chagas disease (American trypanosomiasis), leishmaniasis and Argentine hemorrhagic fever (AHF), among others.