Papers by Joshua Schoolcraft
14th International Conference on Space Operations, 2016
Space Operations: Innovations, Inventions, and Discoveries, 2015
Congestion control is an important feature that directly affects network performance. Network con... more Congestion control is an important feature that directly affects network performance. Network congestion may cause loss of data or long delays. Although this problem has been studied extensively in the Internet, the solutions for Internet congestion control do not apply readily to challenged network environments such as Delay Tolerant Networks (DTN) where end-to-end connectivity may not exist continuously and latency can be high. In DTN, end-toend rate control is not feasible. This calls for congestion control mechanisms where the decisions can be made autonomously with local information only. We use an economic pricing model and propose a rule-based congestion control mechanism where each router can autonomously decide on whether to accept a bundle (data) based on local information such as available storage and the value and risk of accepting the bundle (derived from historical statistics). Preliminary experimental results show that this congestion control mechanism can protect routers from resource depletion without loss of data.
In this work, we present sensing performance using an architecture for a reconfigurable protocol ... more In this work, we present sensing performance using an architecture for a reconfigurable protocol chip for space-based applications. Toward utilizing the IP packet architecture, utilizing data link layer framing structures for multiplexed data on a channel are the targeted application considered for demonstration purposes. Specifically, we examine three common framing standards and present the sensing performance of these standards and their relative de-correlation metrics. Some analysis is performed to investigate the impact of lossy links and on the number of packets required to perform a decision with some probability. Finally, we present results on a demonstration platform that integrated reconfigurable sensing technology into the Ground Station Interface Device (GRID) for End-to-End IP demonstrations in space.
In this work, we present sensing performance using an architecture for a reconfigurable protocol ... more In this work, we present sensing performance using an architecture for a reconfigurable protocol chip for space-based applications. Toward utilizing the IP packet architecture, utilizing data link layer framing structures for multiplexed data on a channel are the targeted application considered for demonstration purposes. Specifically, we examine three common framing standards and present the sensing performance of these standards and their relative de-correlation metrics. Some analysis is performed to investigate the impact of lossy links. Finally, we present results on a demonstration platform that integrated reconfigurable sensing technology into the Ground Station Interface Device (GRID) for End-to-End IP demonstrations in space.
2013 IEEE Aerospace Conference, 2013
The Robot Application Programmer Interface Delegate (RAPID) is a pipeline designed for teleroboti... more The Robot Application Programmer Interface Delegate (RAPID) is a pipeline designed for telerobotic operations in the Human Exploration Technology (HET) Program. As human spaceflight missions become more ambitious and far reaching (for example, long duration operations on board ISS or around near-Earth asteroids), traditional telerobotic technology becomes expensive, unwieldy and difficult to scale. We present a RAPID deployment architecture that leverages the advantages of COTS internetworking infrastructure while enjoying many of the benefits of space-optimized Delay/Disruption Tolerant Network (DTN) technology. DTNTAP is a multi-platform secondgeneration IP over DTN implementation with performance and usability improvements over its predecessor. Selected results from functional and performance tests are presented and new capabilities are described.
SpaceOps 2010 Conference<br> <b><i>Delivering on the Dream</b></i><br> <i>Hosted by NASA Marshall Space Flight Center and Organized by AIAA</i>, 2010
2011 International Conference on Space Optical Systems and Applications (ICSOS), 2011
SpaceOps 2006 Conference, 2006
SpaceOps 2006 Conference, 2006
... V. DTN Mars Network Experiments The team performed experiments in two different settings. ...... more ... V. DTN Mars Network Experiments The team performed experiments in two different settings. ... developed at NASA/JPL are built upon QualNet; these include the complete CCSDS protocol stack: Proximity-1, Packet Telemetry/Telecommand ... Each bundle is 1 Megabyte in size. ...
A lunar surface systems study explores the application of optical communications to support a hig... more A lunar surface systems study explores the application of optical communications to support a high bandwidth data link from a lunar relay satellite and from fixed lunar assets. The results show that existing 1-m ground stations could provide more than 99% coverage of the lunar terminal at 100Mb/s data rates from a lunar relay satellite and in excess of 200Mb/s from a fixed terminal on the lunar surface. We have looked at the effects of the lunar regolith and its removal on optical samples. Our results indicate that under repeated dust removal episodes sapphire rather than fused silica would be a more durable material for optical surfaces. Disruption tolerant network protocols can minimize the data loss due to link dropouts. We report on the preliminary results of the DTN protocol implemented over the optical carrier.
IEEE Intelligent Systems, 2000
Space missions have typically been designed to operate via direct point-to-point communications t... more Space missions have typically been designed to operate via direct point-to-point communications to and from Earth. Although this configuration is still the standard design, for some time this stand-alone approach has been changing because of a variety of factors. ...
American Institute of Aeronautics …, 2007
Congestion control is an important feature that directly affects network performance. Network con... more Congestion control is an important feature that directly affects network performance. Network congestion may cause loss of data or long delays. Although this problem has been studied extensively in the Internet, the solutions for Internet congestion control do not apply readily to ...
Proceedings of the Third Ieee International Conference on Space Mission Challenges For Information Technology Volume 00, Jul 19, 2009
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.
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Papers by Joshua Schoolcraft