Papers by Leigh Torgerson
SpaceOps 2006 Conference, Jun 19, 2006
NASA's demonstration of the successful transmission of relay data through the orbiting Mars Odyss... more NASA's demonstration of the successful transmission of relay data through the orbiting Mars Odyssey, Mars Global Surveyor, and Mars Express by the Mars Exploration Rovers has shown not only the benefit of using a relay satellite for multiple landed assets in a deep space environment but also the benefit of international standards for such an architecture. As NASA begins the quest defined in the Vision for Exploration with robotic and manned missions to the Moon, continues its study of Mars, and is joined in these endeavors by countries worldwide , landed assets transmitting data through relay satellites will be crucial for completing mission objectives. However, this method of data delivery will result in increased complexity in routing and prioritization of data transmission as the number of missions increases. Also, there is currently no standard method among organizations conducting such missions to return these data sets to Earth given a complex environment. One possibility for establishing such a standard is for mission designers to deploy protocols which fall under the umbrella of Delay Tolerant Networking (DTN). These developing standards include the Bundle Protocol (BP) which provides a standard, secure, store and forward mechanism designed for high latency and asymmetric communication links and the Licklider Transmission Protocol (LTP) which is used to provide a reliable deep space link transmission service.
This report covers the initial DARPA DTN Phase 3 activities as JPL provided Core Engineering Supp... more This report covers the initial DARPA DTN Phase 3 activities as JPL provided Core Engineering Support to the DARPA DTN Program, and then further details the culmination of the Phase 3 Program with a systematic development, integration and test of a disruption-tolerant C2 Situation Awareness (SA) system that may be transitioned to the USMC and deployed in the near future. The system developed and tested was a SPAWAR/JPL-Developed Common Operating Picture Fusion Tool called the Software Interoperability Environment (SIE), running over Disruption Tolerant Networking (DTN) protocols provided by BBN and MITRE, which effectively extends the operational range of SIE from normal fully-connected internet environments to the mobile tactical edges of the battlefield network.
SpaceOps 2010 Conference, Apr 25, 2010
The Interplanetary Overlay Network (ION) software at JPL is an implementation of Delay/Disruption... more The Interplanetary Overlay Network (ION) software at JPL is an implementation of Delay/Disruption Tolerant Networking (DTN) which has been proposed as an interplanetary protocol to support space communication. The JPL Deep Impact Network (DINET) is a technology development experiment intended to increase the technical readiness of the JPL implemented ION suite. The DINET Experiment Operations Center (EOC) developed by JPL's Protocol Technology Lab (PTL) was critical in accomplishing the experiment. EOC, containing all end nodes of simulated spaces and one administrative node, exercised publish and subscribe functions for payload data among all end nodes to verify the effectiveness of data exchange over ION protocol stacks. A Monitor and Control System was created and installed on the administrative node as a multi-tiered internetbased Web application to support the Deep Impact Network Experiment by allowing monitoring and analysis of the data delivery and statistics from ION. This Monitor and Control System includes the capability of receiving protocol status messages, classifying and storing status messages into a database from the ION simulation network, and providing web interfaces for viewing the live results in addition to interactive database queries.
For nearly a decade, NASA and many researchers in the international community have been developin... more For nearly a decade, NASA and many researchers in the international community have been developing Internet-like protocols that allow for automated network operations in networks where the individual links between nodes are only sporadically connected. A family of Disruption-Tolerant Networking (DTN) protocols has been developed, and many are reaching CCSDS Blue Book status. A NASA version of DTN known as the Interplanetary Overlay Network (ION) has been flight-tested on the EPOXI spacecraft and ION is currently being tested on the International Space Station. Experience has shown that in order for a DTN service-provider to set up a large scale multi-node network, a number of network monitor and control technologies need to be fielded as well as the basic DTN protocols. The NASA DTN program is developing a standardized means of querying a DTN node to ascertain its operational status, known as the DTN Management Protocol (DTNMP), and the program has developed some prototypes of DTNMP software. While DTNMP is a necessary component, it is not sufficient to accomplish Network Monitor and Control of a DTN network. JPL is developing a suite of tools that provide for network visualization, performance monitoring and ION node control software. This suite of network monitor and control tools complements the GSFC and APL-developed DTN MP software, and the combined package can form the basis for flight operations using DTN.
This software provides capabilities for autonomous cross-cueing and coordinated observations betw... more This software provides capabilities for autonomous cross-cueing and coordinated observations between multiple orbital and landed assets. Previous work has been done in re-tasking a single Earth orbiter or a Mars rover in response to that craft detecting a science event. This work enables multiple spacecraft to communicate (over a network designed for deep-space communications) and autonomously coordinate the characterization of such a science event. This work investigates a new paradigm of space science campaigns where opportunistic science observations are autonomously coordinated among multiple spacecraft. In this paradigm, opportunistic science detections can be cued by multiple assets where a second asset is requested to take additional observations characterizing the identified surface feature or event. To support this new paradigm, an autonomous science system for multiple spacecraft assets was integrated with the Interplanetary Network DTN (Delay Tolerant Network) to provide communication between spacecraft assets. This technology enables new mission concepts that are not feasible with current technology. The ability to rapidly coordinate activities across spacecraft without requiring ground in the loop enables rapid reaction to dynamic events across platforms, such as a survey instrument followed by a targeted highresolution instrument, as well as regular simultaneous observations.
... Mars Observer Non-stored Commanding Process Robert N. Brooks Jr. ... Thus, the projeet began ... more ... Mars Observer Non-stored Commanding Process Robert N. Brooks Jr. ... Thus, the projeet began taking steps to enhance the capabilities of the flight team. Onc mechanism used by project management was a tool available from TOMI Quality Management (TQM). ...
IEEE Aerospace and Electronic Systems Magazine, Jul 1, 2020
This article is the second of a three-part series in which we present the results of a study expl... more This article is the second of a three-part series in which we present the results of a study exploring concepts for improving communications and tracking capabilities of deep space SmallSats. In Part I, we discussed SmallSat direct-to-earth links and SmallSat communications equipment, and provided recommendations for future work. In Part II, we focus on SmallSat navigation options, Disruption Tolerant Networking (DTN), proximity links, and the use of the communication link for science observations, and we provide recommendations for future work. We have examined both radio and optical navigation options, and considered autonomous and semiautonomous navigation to reduce operational costs for planetary SmallSats. We note that communication link resilience to delay and disruption enhances spacecraft autonomy; therefore, we have provided a discussion of DTN to indicate that using DTN allows for automated data transmission and recovery, therefore, reducing manual operations. SmallSats in deep space may utilize a relay spacecraft for communications with earth or function as a relay for landed and in-orbit assets. We present a detailed examination of relay proximity links and networks where we address both proximity hardware and networking scenarios. The proximity link features that we examine include the network architecture and its relationship to DTN, proximity radios and antennas, communications link performance, and proximity navigation. The use of the communication link for science has been practiced by primary missions in deep space scenarios. (Two examples of past planetary radio science experiments can be found in the following: https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/radio-science-subsystem/ and https://www.boulder.swri.edu/pkb/ssr/ssr-rex.pdf) Likewise, SmallSats can offer their radio links for radio science investigations. This article provides a brief introduction to radio science and presents the prerequisite features necessary for radio science observations by SmallSats. We conclude with nine recommendations based on the findings of the study. These recommendations are guidelines on the design, implementation, and operation of deep space SmallSat communication links. The adoption of some or all of the guidelines should result in an enhanced communication and tracking capability for the deep space SmallSat missions.
IEEE Communications Magazine, Jun 1, 2003
Increasingly, network applications must communicate with counterparts across disparate networking... more Increasingly, network applications must communicate with counterparts across disparate networking environments characterized by significantly different sets of physical and operational constraints; wide variations in transmission latency are particularly troublesome. The proposed Interplanetary Internet [1], which must encompass both terrestrial and interplanetary links, is an extreme case. An architecture based on a "least common denominator" protocol that can operate successfully and (where required) reliably in multiple disparate environments would simplify the development and deployment of such applications. The Internet protocols are ill suited for this purpose. We identify three fundamental principles that would underlie a delaytolerant networking (DTN) architecture and describe the main structural elements of that architecture, centered on a new end-to-end overlay network protocol called Bundling. We also examine Internet infrastructure adaptations that might yield comparable performance but conclude that the simplicity of the DTN architecture promises easier deployment and extension.
IEEE Communications Magazine, Jun 1, 2003
Increasingly, network applications must communicate with counterparts across disparate networking... more Increasingly, network applications must communicate with counterparts across disparate networking environments characterized by significantly different sets of physical and operational constraints; wide variations in transmission latency are particularly troublesome. The proposed Interplanetary Internet [1], which must encompass both terrestrial and interplanetary links, is an extreme case. An architecture based on a "least common denominator" protocol that can operate successfully and (where required) reliably in multiple disparate environments would simplify the development and deployment of such applications. The Internet protocols are ill suited for this purpose. We identify three fundamental principles that would underlie a delaytolerant networking (DTN) architecture and describe the main structural elements of that architecture, centered on a new end-to-end overlay network protocol called Bundling. We also examine Internet infrastructure adaptations that might yield comparable performance but conclude that the simplicity of the DTN architecture promises easier deployment and extension.
SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate,... more SEE PROFILE All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately.
Disruption-tolerant networking (DTN) is an approach to networks that can withstand drops in conne... more Disruption-tolerant networking (DTN) is an approach to networks that can withstand drops in connectivity and long transmit times. One important application of DTN is an interplanetary Internet among the numerous spacecraft in the Solar System. The Interplanetary Overlay Network (ION) is an implementation of DTN developed at JPL. To allow for network monitoring, ION nodes write status outputs to local files and stdout. Previously, ION network monitoring was done by remotely viewing each node’s status outputs in terminal windows, which quickly became cumbersome for large networks. In this project, we prototyped a more effective system for monitoring ION networks. First, each node sends its status outputs to a remote machine via TCP. Then, an application on the remote machine reads the status outputs from TCP, stores them in a database, and displays them in a flexible, user-friendly graphical user interface. The application was built using Logstash (log pipeline), Elasticsearch (databa...
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Papers by Leigh Torgerson