Rafael enters the “New Space” with micro-satellites/
Satellite Motor Plant
To this day, Rafael has been involved in space propulsion and provided lateral solutions, from propulsion elements to the supply of complete propulsion systems for prompt integration in satellites, including support for satellite refueling at the launch site. Rafael’s space propulsion activity is concentrated by the company’s Manor Division. As part of their propulsion solutions, Rafael develops and supplies electrical propulsion systems and components for use in space. Electrical propulsion is regarded as a “green” space propulsion technology, as it uses Xenon gas – a noble, non-toxic, non-polluting gas.
Rafael’s electrical propulsion systems are low and medium power units designed for both maintaining and changing orbit in different satellite types, including constellations of low-level communication satellites and GPS satellites. Rafael’s space propulsion kits are already used on numerous satellites in Israel and around the world, including the Ofek satellites and international satellite projects worldwide, which include constellations of communication and surveillance satellites such as the GlobalStar-2 constellation, the O3B constellation, Sentinel-1 satellites and others.
Another example of Rafael’s cooperative alliances is Project Venus – an Israeli-French cooperative alliance that uses both a chemical propulsion system (based on hydrazine) and an electrical propulsion system by Rafael. In the context of another cooperation agreement between the Israel Space Agency at the Ministry of Science, Technology & Space and the European Space Agency (ESA), an agreement for the development of low power (100-250 watts) electrical space propulsion systems was kicked off in 2014. Rafael and the ALTA Company of Italy will develop those systems. Electrical propulsion systems of this type are intended for integration in micro-satellites and will be integrated as a separate satellite propulsion module designed to operate at very low electrical power rates of 100 to 250 watts.
“During the 1980s, Rafael was encouraged to build a launching vehicle and a propulsion system in order to support the space activity of IAI,” says Zvi Z, marketing manager at the Space Administration of Rafael’s Manor Division. “Most of our revenue in the international space market is generated by propulsion systems. We sell complete modules or individual elements like motors and fuel tanks. Propulsion is the primary element of the satellite, and to this day our record has shown 100% reliability. There are more than 66 satellites out there in space that contain products by Rafael.
“An interesting fact: Israel does not belong to the European Space Agency, so we are not entitled to participate in their tenders. Nevertheless, we participate in those programs as Europe purchases hardware from Israel. Over the last decade and a half we entered the field of electrical motors. Electrical propulsion was originally invented by the Russians and applied in missions involving deep space probes and keeping communication satellites in orbit. The Amos-6 satellite will have the same system.
“Rafael is a pioneer in the field of low-power electrical propulsion. The Venus satellite will use electrical propulsion by Rafael. The entire system. It will be the first demonstrator of this system in space. It will be a motor in the range of 100-250 watts. In comparison, communication satellites have a 1.5 kilowatt motor. This system is intended for satellites weighing 150 kg to 1 ton.
“Electrical propulsion provides an advantage to a small surveillance satellite because of another aspect – resolution. With a micro-satellite, resolution can be improved if you descend to a low level, and at these levels there are small molecules of air that create drag. As electrical propulsion is 5-6 times more effective than chemical propulsion, it can maintain the satellite at the appropriate altitude for a longer period of time. Chemical propulsion cannot be used on small satellites owing to the weight of the fuel. For every 10 kg of electrical propulsion you will need 60 kg of chemical propulsion.
“With electrical propulsion I take one sixth with me, and receive the rest of the energy from the sun. For 200 watts of power, you need one square meter of solar panels, or even less. As the world is heading toward constellations of hundreds or thousands of small satellites, the future is in electrical propulsion. We are in contact with One Space, Google and other companies in this field.”
The new system developed by Rafael and ALTA of Italy will weigh about 15 kg only, and it will be highly fuel-efficient. Its light weight will enable satellites to carry larger payloads than those used to this day and extend the satellites’ life expectancy in earth orbiting missions.
“Seven years ago we decided to become involved in the development of complete satellites in the mini, micro or nanosatellite categories,” says Jacob S, marketing manager at Rafael’s Air & Intelligence Division. “These satellites weigh 10-15 kg or 100-120 kg. The objective is to manufacture a constellation that will circle the earth every hour. We developed two applications. One – a 100 kg micro-satellite for earth surveillance with a resolution of 50 cm, in color, which includes electrical propulsion. This satellite will operate for 7 years at a level of 300 km.
“The other application is a 10-15 kg nanosatellite. Owing to the technological development of lightweight, wide bandwidth radio transceivers, it is now possible, using a constellation of 12-24 satellites, to provide communication relaying almost anywhere around the world using ad-hoc systems for tactical units. We are talking about a delay of 20 milliseconds. The rate depends on the terminal. When the terminal is mounted on a vehicle with an adjustable antenna that follows the beam, you can reach rates of up to 8 Mbit/sec. At these rates you can transmit several live video channels and operational quality still images, including voice and data. The solution provides communication relaying for an area with a radius of 300-400 km, between all of the elements involved, including communication with a command post located 1,000 km away from the forces on the ground.”
Along with the development of satellites, Rafael also develops missiles, so, in theory, it can provide both the satellite and the launch. However, the people at Rafael say that this option is not on the agenda at the moment. Additionally, Rafael has not launched such a constellation into space yet. “We are considering the possibility of launching a demonstration constellation,” says S. “Regarding the launch, we are not currently entering the development of ground launching capabilities. These systems are designed to be launched from an extensive range of launching platforms, including the IAI Shavit launcher. One of the advantages of nanosatellites is that you launch all of them from the same launching vehicle, into the same orbit. Otherwise, the satellite would have lost fuel when switching between different orbits. As far as the launch is concerned, there are broker companies that specialize in launch coordination.
“Our solution is intended for intelligence and military purposes primarily. We focus on selling such constellations to countries that aspire for independence in space. A constellation of 12 satellites can photograph a given point at one-hour intervals. This is intermittent, rather than continuous tracking. In the future, we will not deny ourselves the option of entering the field of services as well.”