The T-Minus CanSat launcher is a 3.17 meter tall rocket, capable of launching and deploying 6 CanSats simultaneously at an altitude in excess of one kilometre. The rocket itself has a diameter of 0.2 meters. The rocket has an "ogive-shaped" nosecone and a conical tail cone for good aerodynamic performance after motor burnout. The mass of the rocket, including 6 CanSats, parachute and rocket motor, is approximately 23 kg.
The rocket is equipped with a parachute in order to safely recover the vehicle. When landing correctly, the vehicle could be re-used after a refurbishment and check-out. The vehicle is aerodynamically stabilized and has no active stabilisation controls. The rocket motor produces 4300 Ns of impulse, and has a burn time of 4.2 seconds. The propellant formulation is chosen such that the environmental impact is as low as possible.
In order to speed up the actual launching operations, the vehicle is divided into two sections:
- A fin section, which contains the rocket motor and other pyrotechnical equipment. This section is stored away from the students.
- The CanSat bay, which houses the six CanSats, is completely non-pyrotechnical. It is the only part with which the students interact.
The bay is designed such that the loading time of the CanSats in the bay is minimized. The operations during the campaign and the design of the T-Minus CanSat Launcher are such that the time between CanSat switch-on and launch is less than 30 minutes. The CanSats will leave the rocket in radial direction. This is done so that the ejected CanSat will not collide with the rocket itself during flight. The rocket does not use pyrotechnics to eject the CanSats, so that the deployment shock on the CanSat is reduced dramatically. The CanSats are pushed out of the rocket via a small spring, minimizing the chance of a CanSat “being trapped” in the CanSat bay itself. The hatches which secure the CanSat’s in the bay will be lost after each flight. The Cansat is held in a small dispensable cardboard holder in the bay in order to secure a good and smooth deployment of the CanSat.
The rocket is powered by a simple solid rocket motor with 6.5 kg loaded mass, of which 4.2 kg is rocket propellant. The propellant is considered a green propellant and is made in such way that almost all exhaust products are biodegradable. The rocket motor and all other components which contain pyrotechnics are in a separate part of the launch-field and do not need to be in contact with the CanSat participants of the CanSat launch day. The motor is designed such that it produces smoke after motor burnout, this reduces drag and increases visibility for the CanSat participants, so they are able to track the rocket and point the antenna’s to the proper position in the sky.
The T-Minus CanSat Carrier
Since not every launchfield is suitable for launching CanSats via rockets, T-Minus is currently working on a CanSat Carrier, a remotely piloted aircraft, with computer guidance, to launch CanSats from lower altitude, but with a higher precision. The launchfield on where the CanSat activities are done can be smaller and the systems doesn’t need any complex permits for the rocket motor. The aircraft is completely electrically powered and can drop 2 CanSats per sortie. Since the battery is easily swappable, a lot of sorties can be done per day. Therefore it should be possible to do a complete CanSat competition of 20 teams in one day. It is also possible to drop the CanSats at a specified point in the sky, thereby lowering the dispersion of the CanSats due to wind. T-Minus is currently in the developing stage of the aircraft. Actual droppings of CanSats are expected in the next months.