PROBLEM IN SPACE DEVELOPMENT
With the rapid development of private space companies, and the miniaturization of space satellites, ridesharing to space - i.e. launching multiple satellites into the same orbit using a single rocket - has become the most common way to send satellites into space. Ridesharing has the advantages of increased launch opportunities and reduced launch costs, however, there are no safe and high thrust propulsion systems that rideshare satellite can use to travel the “last mile” to more desirable orbits. Most small satellites remain stuck in the rideshare orbit, and space developers are limited to a narrow range of orbits.
Propulsion Devices(Kick Motor)
Image of Satellites Ridesharing
Trade-offs in Propulsion Systems
While these propulsion systems are relatively safe, they take a much longer time to travel, because they produce only about 1/100,000 of the propulsive power of liquid fuel. Also, their slow speeds lead to other challenges, such as prolonged exposure to Earth's radiation belts, which damage the satellite's solar cells, integrated circuits, electronic components, and sensors, and/or the need to constantly power the propulsion system.
Liquid fuels can provide high propulsive force; however, they lead to large safety management costs for fuel handling, and system redundancy. The smaller the size of liquid fuel propulsion systems, the larger the proportion of safety management and risk reduction costs become. Therefore, using liquid fuels as propulsion systems for small satellites is not suitable for private companies which need to keep the costs of production as low as possible.
Comparison of Thrust Levels
・Ions Propulsion : 0.001 N
・Water Vapor Propulsion : 0.002 N
・Gas Propulsion : 1.000 N
・Liquid Fuel Propulsion: 100.000 N
HYBRID PROPULSION SYSTEM
In 2017, the Hokkaido University Laboratory of Space Systems was selected to become a JAXA Institute of Space and Astronautical Science (ISAS) Joint University Collaboration Center, or "University Space Hub," with the aim to accelerate research and development of hybrid propulsion to enable rideshare-based deep space exploration missions.
Hybrid propulsion is the subcategory of chemical propulsion that utilizes the combustion of a solid (state) fuel, and liquid (or gaseous state) oxidizer for creating a propulsive force. Since solid fuels are inherently non-toxic, non-flammable, and non-explosive, hybrid propulsion is the safest type of chemical propulsion.
Letara is working on research and development of this hybrid propulsion technology for small spacecraft to provide safe and fast “last-mile delivery” in space, and to be the driving force of a logistics network covering the entire solar system.
A high thrust on the order of 100 N is produced for the rapid orbital transfer of small satellites - note that this is no less than the thrust of liquid fuel systems.
*100 N = 10kg on the ground
*40,000 N (and various thrust levels in between) have been demonstrated in experiments of Hokkaido University.
Since it is made from common plastic, the fuel can be handled with bare hands.
*NFPA 704 Fire Diamond standard (4 is the most dangerous, 0 is completely safe), established by the National Fire Protection Association to indicate chemical hazards
Letara's systems have a Toxicity of 2 - Flammability of 0 - and Explosiveness of 0 So there is are no special requirements for storing or handling our systems.
Recycled plastics can be used, and also any other types of solid hydrocarbons can be used as a fuel. The raw material costs are low, the size and shape can be customized with COTS 3D printers, manufacturing costs are low, the system is highly scalable, long-term storage is simply, and we can help put plastic waste on the ground to good use!
Notoriously difficult to combust, yet safe and high-density oxidizers can be used reliable for the first time.
*Patent pending technology
Performance Simulation Program
The leading edge analysis program enables nozzle erosion prediction and more accurate performance evaluation
Proprietary low-voltage , low power solid fuel (re-)ignition system to expand the range of applications in space
*Patent pending technology
Optimum Design Program
This program allows for maximum propulsive performance while placing the necessary components in a limited space for ridesharing.
Japan's only vacuum combustion test facility for small-scale space propulsion enables rapid development and testing on the ground.
Ground Testing Expertise
Highly accurate performance prediction based on >20 years of experimental research experience and proprietary algorithms