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Advanced Exploration Systems Division

Logistics Reduction: RFID Enabled Autonomous Logistics Management (REALM) (LR-REALM)

Active Technology Project

Project Introduction

The Advanced Exploration Systems (AES) Logistics Reduction (LR) project Radio-frequency identification (RFID) Enabled Autonomous Logistics Management (REALM) task focuses on the subset of autonomous logistics management functions pertaining to automated localization and inventory of all physical assets pertaining to, or within, a vehicle utilizing RFID technologies. REALM technology can provide detailed data to enable autonomous operations such as automated crew procedure generation and robotic interaction with logistics and deep space habitats; this is especially of value where communication delays with Earth drive the need for self-reliance.  The REALM project will conduct a series of ISS technology demonstrations.  The first ISS demonstration, REALM-1, started in February 2017 and was completed at the end of FY19 when it was transitioned to the ISS program for sustaining operations.  The second ISS demonstration, REALM-2, started late 2019 and will continue for at least one year.

The problem of locating all mission items within and around a vehicle is complicated by many factors, including the desire to rely only on passive tags, restrictions on RF transmit power, layered storage of logistics, the challenging RF scattering environment of vehicles, and metallic storage enclosures. To address this complex problem, associated RFID technologies are partitioned into three classes:

Dense Zone technologies

Sparse Zone technologies

Complex Event Processing

Dense Zone technologies pertain to enclosures with conductive, or shielded, boundaries and an integrated RFID reader to interrogate the items contained therein. Sparse zone technologies address all areas exclusive of the dense zones, including the open areas of a habitat module in addition to crevices, for example, behind a rack. These technologies include fixed-zone readers, steered-beam antenna readers, and mobile readers such as robotic elements, crew-held readers, or crew-worn readers. With both dense and sparse zones, guaranteed real-time, on-demand reads are not possible, so “smart” applications, e.g., Complex Event Processing (CEP), are required to infer item locations based on context from the sparse and dense zone technologies.

Mission details might drive a different combination of these three technologies. Therefore, in addition to maturing these individual technology areas, the LR REALM team will learn which combinations of technologies are best suited for specific missions. For example, dense zone technologies can be made highly accurate but entail greater mass compared to sparse zone technologies. Sparse zone technologies typically cover greater volume per reader, but are more apt to miss tags because they cover a larger area. They still require readers, cables, and antennas to accomplish their function. The operational intelligence provided by CEP can likely be traded for the size, weight, and power associated with dense and sparse zone technologies, but the extent, and specific implementation, remain as knowledge gaps to be addressed by this effort.

The REALM task is divided into four sub-technology projects: REALM-1, -2, -3, -6DoF, and REALM-RFID Sensing


REALM-1 infrastructure will be developed and evaluated on ISS, with RFID hatch readers and antennas deployed in ISS Node 1, U.S. Laboratory, and Node 2. A ground-based CEP center will receive data from the ISS hatch readers and will provide operational intelligence that infers item locations. This effort is in collaboration with the ISS program payloads office and the ISS vehicle office, both of which provide cost sharing for development.  In FY15, manufacturing of the hatch readers, known as EMBER (EMBEdded RFID Reader), began, along with resident software development. In parallel, the CEP center was established, and the CEP team, including a university partner, began tailoring prior CEP work to NASA’s REALM goals. The REALM Test Bed was utilized for testing CEP concepts of operation prior to the processing of ISS REALM-1 data in succeeding years. In FY16, the hatch readers, antennas, and RF cables were developed. REALM-1 was launched December 2016. Testing, evaluation, and advancement of the CEP will continue using the REALM Test Bed in advance of REALM-1 data downlinked from ISS. FY17 through FY19 were devoted to the 24-month ISS technology demonstration of REALM-1.  Multiple cycles of visiting vehicles, and the subsequent loading, off-loading, and translation of cargo through ISS will provide for thorough REALM-1 assessment.  During this time, the CEP software will reside in a ground system and utilize the ISS REAM-1 data with crew activity data, inventory surveys, and imagery to improve the CEP location algorithms and evaluate the effectiveness of the hatch reader locations and ability to assess tagged item locations in non-REALM instrumented nodes.  The REALM-1 system was considered sufficiently matured in FY19 and was transitioned to an operational ISS system midway through FY19, so that ISS became responsible for sustaining engineering of flight and ground REALM-1 assets. 

AES is continuing CEP evolution.  Targets for CEP evolution include extensions to permit one-half-rack level localization (i.e., bay and quadrant – overhead, deck, port, starboard).  Conventional deterministic algorithms were initially the most promising in terms of location accuracy; however, late in FY19 two machine learning/artificial intelligence (AI) approaches began to show considerable promise. 


REALM-2 is an AES LR RFID interrogator payload on the Space Technology Mission Directorate (STMD) Next Generation Free-Flyer (NGFF), aka Astrobee, located inside the ISS, that will take RFID "snapshots" during cargo movement and refine item localization. In FY15, REALM-2 and Astrobee project teams initiated discussions and identified a preliminary payload architecture and preliminary interfaces. In FY16, the REALM-2 activity initiated formal interface development with the Astrobee project.  The REALM-2 task also initiated development of flight software that will reside in the mobile reader.  In FY17 and FY18, REALM-2 matured portions of the flight hardware design and software.  The REALM-2 flight hardware was fabricated in FY19.  Ground testing with an integrated flight-like Astrobee configuration was completed. In FY19, all REALM-2 flight hardware and safety certification were completed.  The REALM-2 flight system was delivered for a November FY20 launch.  End-to-end Astrobee ground integration tests occurred in October with the REALM-2 team at JSC controlling the Astrobee certification unit/REALM-2 reader on the granite table at ARC.  Crew installation of REALM-2 is expected to occur in late January or February 2021, with commissioning and early experiments occurring by May. 

Significant early benefits of the Astrobee and REALM-2 systems are anticipated in the provision of new training data for REALM-1, as well as new vantage points provided by the REALM-2 system for the CEP location engines.  Although early commissioning and experiments will occur in the ISS Japanese Pressurized Module (JPM) module, REALM-2 experiments in other modules, including Node3, will occur as Astrobee commissioning extends to those modules.  Node3 is of particular importance as it is not currently instrumented by REALM-1, and the adjoining Permanent Multi-Purpose Module (PMM) is the primary ISS logistics module. 


REALM-3 will provide a smart cargo transfer bag (CTB) or rack drawer that can provide immediate feedback to the crew regarding items required for work or experiments. In FY15, REALM-3 was a small task and used the RFID Multipurpose Cargo Transfer Bag (MCTB) prototypes to test various configurations.  These tests supported REALM-1/CEP development and supported inquiries from potential future collaborators. In FY16 through FY18, REALM-3 was limited in scope.  The REALM team determined concepts of operation and benefits of the RFID-enabled CTB in coordination with stakeholders. In FY19, REALM-3 was developed and in FY20, planning for an ISS flight demonstration activity is underway for FY21. 

REALM-6DoF (6 degrees of freedom)

The REALM team is collaborating with Advanced Systems and Technologies (AS&T) to advance an ultra-precise WHISPER (Wireless Hybrid Identification and Sensing Platform for Equipment Recovery) RFID tracking system that will be compatible with the REALM-1 infrastructure.  The AS&T WHISPER technology is being developed under a Small Business Innovative Research (SBIR) award.  Their new tag and tracking system enhancement permits theoretical tracking accuracies at or below the 10-centimeter level and also permits orientation tracking. In FY20, the REALM team and AS&T will assess flight readiness and advance towards flight designs of the key hardware components.  AS&T will develop the second version projector, the IWPv2, which will be the final flight form factor.  Select components will be evaluated for space thermal and ionizing radiation environments.  Specific con-ops for an ISS TD will be developed, reader synchronization plan will developed, and a crew-assisted calibration process will be developed.  In addition, hardware prototypes will be delivered by AS&T to the REALM team to permit performance evaluation and begin system software integration.


The REALM team is leveraging RFID integrated circuits (ICs) that offer serial interfaces in addition to the more conventional over-the-air radiated interface to an RFID tag.  The serial interface permits attachment of a microcontroller and low-power sensors such that the resulting tag is capable of returning sensor data in addition to the typical code that uniquely identifies the tag.  In FY20, the REALM team is applying this technology in the form of RFID tags that monitor drawer state; i.e., “open” or “closed.”  These drawer sensor tags will be read by the REALM-1 readers.  In addition, the REALM-1 system will read tagged items until they are placed inside of a drawer and cease to be “seen.”  Data pulled from the drawer sensor tags will relay changes in drawer state and the time of those events.  The CEP system will use that sensor data, in addition to the data read from the sought tag, and infer whether the tag has been moved into a drawer.

Also, in 2018, the REALM-1 software was modified in the REALM ground analog to retrieve data from the tag user memory banks, in preparation for WHISPER tags and wearable CO2 sensing tags.  New tag antennas were conceived and modeled for support of WHISPER and RFID-sensing functions.  AES LR awarded a SBIR phase IIX to AS&T to advance the technology toward flight

In FY19, the REALM team worked with AS&T to formulate a flight experiment plan, and with potential robotic partners to formulate applications relating to robotic precursor missions in which the 6DoF tag system enables robotic grappling and deployment of logistics.

In FY20, due to the potential benefits for ISS and Gateway, Hyper-Distributed RFID Antenna system (HYDRA) has been an early focal point. 

In FY20, the team will develop and certify flight versions of the drawer tags for subsequent delivery for launch and ISS technology demonstration in FY21.  In parallel, the team will advance other sensor types for the RFID tag platform, such as carbon dioxide.

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