There are two primary objectives for project ICEYE are:
The following secondary objective for project ICEYE is:
Apart from the ion emitter itself, the module including housing, reservoir, heater and electrodes was required to be miniaturized. This is particularly challenging since high voltage of up to -10 kV / +10 kV is being used.
The PPU being able to generate high voltage for emitter and extractor, drive the heater and neutralizers, and measuring the reservoir contactless, has been developed from the scratch with COTS components only.
Compared to existing ion sources, the large amount of propellant (up to 250 g) is challenging in terms of heating, surface tension and spilling.
The IFM Nano Thruster addresses the urgent need of a propulsion system for micro- and nano-satellites: its wide range of thrust (1μN to 1mN), the excellent throttability, and a high specific impulse (Isp up to 5000 s), allow to significantly increase the mission range of such satellites. The high Isp on the other hand allows for very high delta-v manoeuvres at a high propellant mass utilization efficiency (80%). The modularity and the small volume (less than 1 dm³ including propellant and electronics) and its light mass (0.8 kg), make the thruster suitable for all small satellites from 1 to 500 kg.
There are major components of the cluster which are essential for proper operation:
The cluster for project ICEYE consists of seven individual and individually controllable IFM nano thruster modules embedded into a common housing.
A common power bus is shared between the seven individual modules but mechanical relays can selectively remove modules therefrom. Two RS-485 communication busses are implemented (one branch with three, another with four modules attached to) which allow communication with the OBC.
The RS-485 transceivers are rad-hard and guarantee unblocking the bus once the supply voltage is removed. This allows the OBC to decide which IFM nano thrusters shall be active.
The project started after the PDR. Before that, prior work was performed to estimate the major risks of the project. All work before kick-off has been reviewed in a PWR. After the design of the housing and the mechanical and thermal simulation, a CDR is planned. Then the thrusters and the housing can be manufactured. The performance of the IFM nano thruster modules is determined individually. After integration into the common housing and a successful operation of the entire cluster, a FRR is scheduled.
After delivery, the cluster is integrated and the spacecraft is launched by the operator. The customer will provide telemetry of the cluster during commissioning phase.
After the CDR the customer requests changes regarding the supply voltage of the power bus (28V instead of 12V) and the communication interface (instead of seven individual RS-422 interfaces, two RS-485 interfaces). This resulted in additional efforts to adapt the PPU and the firmware. In addition, already performed tests regarding performance and thermal management had to be done again. The additional work was done within a CCN. The change of the communication interface is already done; the changes due to the different supply voltage are still being evaluated. Manufacturing of the PPUs is scheduled for November 2017.