CanSat
CanSat (English for cans satellite) is a radio sonde, which is brought into the air either by rocket or via weather balloon but only low levels and thus does not reach a satellite orbit. The construction and launch of a CanSats students demonstrated the overall operations of a real space mission. Due to their low cost, more and more schools and students can also participate in extracurricular CanSat competitions.
For CanSat competitions it is necessary for the payloads that fit into a beverage can size 66 mm diameter and 115 mm in height and have a weight of less than 350 g. Antenna technology, for example, for Automatic Packet Reporting System ( APRS ) can be mounted outside. However, the diameter must not be larger until the CanSat is released itself. The applied landing and retrieval system varies with the height of which can vary depending on the competition. CanSats are generally equipped with a parachute, to limit damage to the landing phase, so that the CanSats can be reused.
- 2.2.1 Barometer
- 2.2.2 thermometer
- 2.2.3 GPS receiver
- 2.2.4 camera
- 2.2.5 Accelerometer
- 2.2.6 Electronic Compass
- 3.1 CanSat to learn the telemetry
- 3.2 Comeback ( recurring ) CanSat 3.2.1 CanSat with parachutes or paragliders
- 3.2.2 CanSat with wings or rotors
Background
In 1998, 50 students came from 12 universities and faculties from the United States and Japan at a symposium in Hawaii. It was the first " University Space Systems Symposium ", which was initiated under the " CanSat Leader Training Program". Here, Bob Twiggs, professor emeritus at Stanford University, co-author of the CubeSat standard and generation radio amateur who proposed the idea, from the later of the nano-satellites standard has developed. The idea to bring a payload volume of a soda can in the atmosphere was formulated. Its volume should be about 350 ml and include the mass should be up to about 500 g. This led to the project ARLISS, which began in 1999, at which involved mainly American and Japanese universities. The implementation of the first start on 11 September of the same year and since then annually. The standard is accepted worldwide and open. The original idea, which is becoming more wide spread, was to launch up to three payloads with 350 ml or a CanSat larger volume. The missile can carry up to 1.8 kg and reach a height of 4000 m. This allows transport flights for about 400 euros. More and more start-ups are funded by public or sponsored contests.
In 2000, the targets of CanSat projects were very different: for example, the calculation of the timing of the opening of the parachute system using barometer data, or the use of a differential GPS system. The conditions for this project became more complex in the year 2001, when the recirculation criterion was come. In the landing phase CanSat to be aligned with a target. This mission was very successful and in 2002, pupils reached the Space Robotics Lab at Tohoku University target an approximation of 45 m and in 2006 by 6 m.
CanSat components
Main parts
Some components can be found in each CanSat:
Battery
It is essential for the operation of all systems is the network-independent supply of energy. The most commonly used due to their performance and power -to-weight ratio Lithium Polymer batteries (LiPo ). The LiPo batteries have a voltage of 3.5 and 3.8V and are often used for mobile phones, cameras or laptops.
Microcontroller
The microcontroller processes the signals from external sensors, such as accelerometers or the altimeter, and controls the transmitter. Most microcontrollers have an internal memory for the determined flight data.
Other instruments
Apart from the above-mentioned components more can be added as part of the competition.
Barometer
It consists of a pressure measuring cell which is connected to the microcontroller, and sends a signal having a voltage value corresponding to the measured air pressure. The microcontroller uses the normal atmospheric pressure differential to calculate the amount.
Thermometer
The operation is similar to that of the barometer, except that the voltage signal for the microprocessor is dependent on the measured temperature. The microprocessor processes this signal by assigning a temperature value.
GPS receiver
The Global Positioning System is the US-based satellite navigation system. From these data the receiver triangulates its position with at least four satellites to achieve higher accuracy. This information is sent to the microcontroller through a serial port.
The GPS receiver should be located at a point in CanSat, are from the from the GPS satellites as possible in the viewing direction.
Camera
A mini camera can be integrated in CanSat housing to film during the flight time or take pictures. Since a CanSat usually can not receive, the microcontroller should trigger signals to operate the camera.
Accelerometer
This sensor consists of one or more accelerometers that are in different axes from one another. An accelerometer can be used to gather data or to determine the position ( by integration). The best accelerometer to determine positions, the inertial navigation system ( INS), respectively. These are used on some CanSat models. The accuracy of the accelerometer is dependent on the calibration of the sensor. Proponents of this sensor will appreciate the fact that GPS is not needed and thus immunity against magnetic interference can be achieved. This allows a free choice of placement within the CanSat housing.
Electronic compass
Sometimes it is necessary to use a compass to determine the direction of flight of CanSats perform, for example, a controlled landing. In this case, the compass sensor is a very small sensor that measures how a traditional compass the angle between the direction and the north. This angle is transmitted to the microprocessor via a potential difference. The microcontroller interprets the incoming signals and acts accordingly. When it is intended to leave the CanSat arrive at a destination without the use of a GPS receiver, this sensor plays a key role.
Types of CanSat
There are essentially two types of CanSat models, as well as an open class:
CanSat to learn the telemetry
Their primary goal is the collection and transmission of data from the flight in real time, called telemetry, which are processed by a ground station. CanSats in this category do not have a control system, since it is not the goal, to land at a certain point, but data during the flight or the case, which is not usually controlled to collect. Of the instruments mentioned in the previous sections are used most frequently: barometer, thermometer, GPS and camera.
Comeback ( recurring ) CanSat
In this type of CanSat the main task is to make this land as close as possible in a controlled manner at a marked by GPS coordinates target. These devices can be navigated by GPS and / or INS. This position is transmitted to the microcontroller which computes the position of the target with the analysis of these data. In turn, the angle is calculated that it must take to reach the target and corresponding instructions are sent to the position control, and navigation electronics ( = control system ). This process is repeated continuously in order to make corrections. Such a returning CanSat also collects data from the flight. But since the number of sensors that can transport the CanSat is smaller, the data obtained are closer than in the previous type. A comeback CanSat always has a control system in order to maneuver to a specific destination.
A distinction is made between comeback CanSat with a parachute or paraglider and / or a rotor and wing.
CanSat with parachutes or paragliders
This CanSat models are, inter alia, equipped with a simple position control mechanism, to produce a change in the longitudinal axis in flight. Thus, the CanSat turns in the one direction or another. This type of control is not very effective with respect to the accuracy of the location, because the landing phase is slow and can make it difficult to control by the large surface of the parachutes weather influences.
CanSat with wings or rotors
Mechanically more complex, but less susceptible to weather conditions as CanSats with parachute or glides. This type of CanSat is due to the higher rate of fall is very difficult to control and requires on board the payload an electronic position control system that corrects several times per second, the tilt and rotation of the rotating CanSats. Shortly before landing, the parachute or paraglider is opened to allow the payload to the landing is usually here.
Open class
In this category, any flying robot, which was not classified in one of the previous two categories of CanSat standards, are presented. Most CanSats in this category are robots to test new systems and new designs that have not been tested yet. (Technology demonstrations ).
Educational objectives:
The low cost of implementation, short preparation time and simplicity of design compared to space projects, make CanSat a popular education project. Since aerospace research is interdisciplinary, offering the use of space technology in the classroom a wide range of attractive themes.
A CanSat project is a learning process, which is known as problem-based learning. One approach that will be provided by successive challenges before open problems in the student. Starting from CanSat design, component integration over, the correct operation, programming, calibration and testing of the components and check up to the launch preparations and the subsequent data analysis, the young scientists are challenged by the distribution of the tasks collaborate in a team. CanSat projects have much to do with research and development of their own skills.
Competitions
The European Space Agency (ESA) initiated a year CanSat competitions for high school students. The competition will serve to attract young people to science and technology in general, and space in particular.
In addition to international and European competitions, there are national competitions. The idea of ESA is that in each ESA member country held a national CanSat Competition and the respective winners of the national competitions then take part in the international and European competition. Currently, the first CanSat Competition in Germany is being prepared. It is planned that the CanSat Competition will be held during the World Space Week 2014.