The intelligent Mass Memory – A versatile memory module for future advanced space borne Mass Memories
- Paper number
IAC-09.B1.4.10
- Author
Prof. Harald Michalik, IDA TU Braunschweig, Germany
- Coauthor
Mr. Dietmar Walter, IDA TU Braunschweig, Germany
- Coauthor
Dr. Torsten Fichna, IDA TU Braunschweig, Germany
- Year
2009
- Abstract
The state of the art Solid State Mass Memory (SSMM) Systems onboard spacecrafts provide ample storage capacity for buffering sensor data onboard satellites and science probes. Today, their main function is this buffering of data in periods without ground contact. Typically no further intelligence is built in. The memory technology is volatile and based on standard synchronous dynamic RAMs (SDRAMs). For the design of future advanced SSMMs the fact of drastically increased sensor data rates (several Gbit/s up to some 10 Gbit/s) and only moderately increased downlink data rate (~1Gbit/s) has to be taken into account. This gap immediately calls for onboard data compression as a standard function of the SSMM. If the onboard sensor system comprises a heterogeneous set of detectors with varying data rates the compression has to be also adaptable. Furthermore, as the SSMM has to accommodate for storage of different data types and volumes (high vs. low data volume, compressed and uncompressed data) a file system is needed in the SSMM for reliable operation from ground. This allows classical file system tasks (like create file, write, read, delete, append etc.) and maintenance functions e.g. for defragmentation. In addition new storage technologies are emerging for implementation in future systems. One example is the use of NAND Flash memory devices. This non-volatile technology has been intensively investigated by us and others for its suitability in space. We have found that with some necessary radiation effects mitigation measures Flash based Memory Modules provide several unique features like huge capacity (several Terabit/module) and non-volatility, which can very favorably support future space missions. Also DDR-SDRAMs, the successor technology of the classical SDRAMs, which support very high data rate access at lower power consumption compared to SDRAMs, by optimized chip design and a double data rate interface are attractive for very high input data rate SSMMs. Here the space suitability of these devices still has to be proven, but this is an ongoing process with most probably positive results. In the paper we outline the architecture and the design of a new generation of intelligent mass memory modules, which integrate hardware support for the system intelligence in terms of compression function and file system support at high to very high access rates. In addition this module is capable to integrate various memory device technologies, i.e. classical SDRAM, NAND Flash and DDR-SDRAMs. We show how the storage requirements of future applications such as high end earth observation missions as well as interplanetary science probes and landers can be satisfied by our versatile and intelligent module design.
- Abstract document
- Manuscript document
(absent)