Kayser Italia announces that the Portable Power Supply mkII is now ready for utilization on the ISS. The launch occurred on 4th of May 2019 on board of SpaceX CRS-17 and with the Falcon 9 rocket.
PPS mkII has been developed by Kayser Italia as subcontractor of AIRBUS DS within a European Space Agency funded project.
The Portable PWR Supply is an autonomous converter unit to distribute 28VDC and USB 5V to one or more payloads (up to four) and taking the upstream power from 120VDC provided by ISS Columbus Module Standard Unit Panel (SUP). The PPS mkII is the extended version of the Portable Power Supply (PPS; previously named KuPS) which have already flown on the ISS since 2011. Maintaining the full compatibility with PPS, the PPS MkII extends the capabilities by a LAN connection to send to Ground data reporting the status of the power supply, using a Web GUI, and two USB connection for chargeable devices or small payloads, increasing the portable power supply versatility. The main goal of PPS and PPS mkII is to simplify the power interface for small payloads to be operated on-board the ISS maintaining the required safety level.
PPS MkII is composed by a metal box containing all the required electronic parts and provided of interface connectors, on/off manual switches and autonomous cooling system (forced air convection). In addition, PPS MkII provides its own input cables necessary to connect it to SUP outlet connectors (120VDC) and to Hirschmann Octopus LAN switch for the LAN connection.
PPS mkII core is a DC\DC converter for main power conversion from 120V to 28V. The input of the converter is managed by an input board which implements all filtering and safety functions on the power line coming from the ISS SUP. One of these functions is the interruption of power, through thermal switches, in case the temperature of the device become too high and can create problem for astronauts touching PPS during nominal operations on-board.
The Output line of the DC\DC converter is managed by an output board which convert the power for the 5V lines and implements all the protections and safety functions on power outlet (i.e.: interruption of power in case of overcurrent).
The PPS mkII microcontroller software has the scope to implement a data exchange interface between PPS mkII and ground via an Ethernet link through a web-based interface. The scope of the link is to receive the status of the power supply visualizing some parameters (currents, voltages, temperatures).
PPS mkII interface for status visualization