A first-of-its-kind satellite is about to perform an unprecedented study, following the effect of climate change on different environments, using Israeli technology. The first Israeli satellite for environmental studies, Venμs, which was built as part of a collaboration between the Israeli and French space agencies, is equipped with an extremely advanced camera. It will image the same areas from the same angle for a long period of time, which will allow the researchers to follow changes in vegetation, precipitation, state of the soil, pollution of water resources and more.
Colors of change
Venus is the Roman mythology equivalent of the Greek Aphrodite, goddess of beauty, love and procreation. In earlier versions of Roman mythology, she was the goddess reigning over gardens, vineyards and orchards. Therefore, it was only suiting to name a satellite on an ecological and agricultural mission after her. Officially, Venμs is an acronym for "Vegetation and Environment monitoring on a New Micro Satellite", with the letter M replaced by the Greek letter μ, which signifies "micro" in scientific formulas.
The central instrument of the satellite is a hyperspectral camera, i.e., a multicolored camera made by Elbit's Elop. It is comprised of twelve detectors, each imaging a different wavelength, i.e., a different color, including wavelengths outside of the visible light spectrum. Accurate analysis of the images using computerized algorithms will allow rapid detection of changes in color of the vegetation, soil or water, which will lead to very early identification of processes, such as vegetation drying out, cold damage, shortage in fertilizer, soil oxidation, water pollution and more. This accurate analysis will allow real-time intervention, and prevention of further damage. For instance, the amount of irrigation or fertilization can be accommodated to the state of the vegetation, pesticide can be applied before an outbreak occurs, or pollution can be identified and controlled before it leads to extensive damage.
Imaging at different wavelengths allows the researchers to also eliminate clouds and other atmospheric interferences from the image, and thus acquire a clear image of the Earth's surface under almost any weather condition.
For efficient follow up, the satellite will image the same exact area every other day. It will complete 29 orbits around the Earth every 48 hours, and on the 30th orbit it will return to the first. The imaging will take place at the same time and angle, with every image covering an area of 760 km2. The images will be sent to a ground station in Lapland in northern Sweden and from there to a laboratory in France that will be performing the analysis. Then, the laboratory will send the information to research facilities in Europe, America, Asia and Africa.
The images of locations in Israel will be sent to the research center at the Sde Boker Campus of Ben-Gurion University, led by Prof. Arnon Karnieli. The areas that will be imaged in Israel include most of the agricultural land in the country, nature reserves, national parks and areas of natural forest.
In order to maintain the constant orbit with high accuracy, the satellite is equipped with an innovative propulsion system, made by Rafael Advanced Defense Systems. The system includes two electrical motors that, by using a magnetic field, turn xenon into plasma, which is a state of matter in which the electrons leave their atoms. The emission of the plasma generates greater thrust than a regular chemical motor, so that the satellite can perform the same maneuvers using less fuel, or perform more maneuvers and track corrections using the same amount of fuel. The electricity for producing the plasma will be generated using solar panels, which the satellite will spread out as it enters into its orbit.
The satellite will orbit the Earth at a height of 720 km, and after two years, will gradually descend into a lower orbit, of about 410 km. During both orbits, it will have to correct its direction and angle every once in a while, due to changes in the gravitational field, solar wind or drag force generated by atmospheric particles. This will be done using an autonomous track control system, which is independent from the instructions and calculations of the operators in the ground control station. Successful function of the novel satellite motor and the track control system may open new markets for using these technologies.
On the way to space
The satellite is 1.70 m tall and 1.20 m wide. With the solar panels spread out, its total width will reach 4.20 m. It weighs 265 kg, including fuel. Despite these impressive dimensions, it is considered a "micro-satellite", since it is small compared to communication and other types of satellites.
The satellite will be launched on top of a Vega rocket from the European Space Agency's launch site in French Guiana, South America. The 30 m-high rocket will also be carrying an Italian observation satellite, which was also manufactured by Israel Aerospace Industries. The launch is scheduled for 10:58pm (local time) on August 1st. In Israel it will be 4:58am on Wednesday, August 2nd. 42 minutes after the launch, the rocket is set to release the Italian satellite into orbit, and 55 minutes later, it will release Venμs. At 10:30am (Israel time), the first dispatch from the satellite should be received in Israel.
During its mission, the satellite is planned to consistently image 110 sites all over the world, which were all chosen for specific experiments out of hundreds of requests that were submitted to the French Space Agency. The data received from the satellite will be utilized for studying the influences of global warming, greenhouse gas emission, afforestation, agriculture and more. In Israel, this project also has educational value, as the data collected will be analyzed as part of high school projects of students in Rishon LeZion and Rehovot, with the financial support of the Israel Space Agency.
The Israel Space Agency in the Ministry of Science invested millions of shekels in development of the satellite and in the research stemming from the data collected by it. In Israel, there is high hope that the investment will be fruitful, not just in generating useful ecological research, but also as a demonstration of the abilities of the civilian Israeli space industry. The success of the mission may serve as an advertisement for the Israeli companies involved in the manufacture and development of the satellite, resulting in a flow of millions of dollars to Israel through signing of additional contracts of satellite and space system manufacture and development.