Roy E. Gladden

Jet Propulsion Laboratory

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Co-Authors

C. D. Edwards

Jet Propulsion Laboratory

Forest Fisher

California Institute of Technology

Daniel A. Allard

Jet Propulsion Laboratory

Michael N. Wallick

California Institute of Technology

Teerapat Khanampompan

California Institute of Technology

Teerapat Khanampornpan

California Institute of Technology

Franklin H. Hy

California Institute of Technology

Charles H. Lee

Jet Propulsion Laboratory

Daniel Wenkert

Jet Propulsion Laboratory

Neil F. Chamberlain

Jet Propulsion Laboratory

Cooperative Institutions

Jet Propulsion Laboratory

California Institute of Technology

Lockheed Martin (United States)

Planetary Science Institute

European Space Research and Technology Centre

European Space Operations Centre

European Space Agency

Stanford University

Johns Hopkins University Applied Physics Laboratory

Massachusetts Institute of Technology

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Enabling international data relay at Mars

2018 SpaceOps Conference (2016)

Daniel Wenkert Peter Schmitz Roy E. Gladden Michel Denis Alistair Winton

10.2514/6.2016-2355

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Citations (5)

Hydrogen On-Orbit Storage and Supply Spacecraft Custom Bus Design

J. N. Carlson Roy E. Gladden

Orbit (dynamics)

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Citations (0)

Mars Reconnaissance Orbiter Wrapper Script

Roy E. Gladden Forest Fisher Teerapat Khanampornpan

The MRO OLVM wrapper script software allows Mars Reconnaissance Orbiter (MRO) sequence and spacecraft engineers to rapidly simulate a spacecraft command product through a tool that simulates the onboard sequence management software (OLVM). This script parses sequence files to determine the appropriate time boundaries for the sequence, and constructs the script file to be executed by OLVM to span the entirety of the designated sequence. It then constructs script files to be executed by OLVM, constructs the appropriate file directories, populates these directories with needed input files, initiates OLVM to simulate the actual command product that will be sent to the spacecraft, and captures the results of the simulation run to an external file for later review. Additionally, the tool allows a user to manually construct the script, if desired, and then execute the script with a simple command line.

File format

Sequence (biology)

Orbiter

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Analyzing Spacecraft Telecommunication Systems

Mark Kordon David Hanks Roy E. Gladden Eric Wood

Multi-Mission Telecom Analysis Tool (MMTAT) is a C-language computer program for analyzing proposed spacecraft telecommunication systems. MMTAT utilizes parameterized input and computational models that can be run on standard desktop computers to perform fast and accurate analyses of telecommunication links. MMTAT is easy to use and can easily be integrated with other software applications and run as part of almost any computational simulation. It is distributed as either a stand-alone application program with a graphical user interface or a linkable library with a well-defined set of application programming interface (API) calls. As a stand-alone program, MMTAT provides both textual and graphical output. The graphs make it possible to understand, quickly and easily, how telecommunication performance varies with variations in input parameters. A delimited text file that can be read by any spreadsheet program is generated at the end of each run. The API in the linkable-library form of MMTAT enables the user to control simulation software and to change parameters during a simulation run. Results can be retrieved either at the end of a run or by use of a function call at any time step.

Interface (matter)

Graphical user interface

Call graph

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Relay Sequence Generation Software

Roy E. Gladden Teerapat Khanampompan

Due to thermal and electromagnetic interactivity between the UHF (ultrahigh frequency) radio onboard the Mars Reconnaissance Orbiter (MRO), which performs relay sessions with the Martian landers, and the remainder of the MRO payloads, it is required to integrate and de-conflict relay sessions with the MRO science plan. The MRO relay SASF/PTF (spacecraft activity sequence file/ payload target file) generation software facilitates this process by generating a PTF that is needed to integrate the periods of time during which MRO supports relay activities with the rest of the MRO science plans. The software also generates the needed command products that initiate the relay sessions, some features of which are provided by the lander team, some are managed by MRO internally, and some being derived.

Orbiter

Payload (computing)

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MaROS: Information Management Service

Daniel A. Allard Roy E. Gladden Jesse J. Wright Franklin H. Hy Gregg Rabideau

This software is provided by the Mars Relay Operations Service (MaROS) task to a variety of Mars projects for the purpose of coordinating communications sessions between landed spacecraft assets and orbiting spacecraft assets at Mars. The Information Management Service centralizes a set of functions previously distributed across multiple spacecraft operations teams, and as such, greatly improves visibility into the end-to-end strategic coordination process. Most of the process revolves around the scheduling of communications sessions between the spacecraft during periods of time when a landed asset on Mars is geometrically visible by an orbiting spacecraft. These relay sessions are used to transfer data both to and from the landed asset via the orbiting asset on behalf of Earth-based spacecraft operators. This software component is an application process running as a Java virtual machine. The component provides all service interfaces via a Representational State Transfer (REST) protocol over https to external clients. There are two general interaction modes with the service: upload and download of data. For data upload, the service must execute logic specific to the upload data type and trigger any applicable calculations including pass delivery latencies and overflight conflicts. For data download, the software must retrieve and correlate requested information and deliver to the requesting client. The provision of this service enables several key advancements over legacy processes and systems. For one, this service represents the first time that end-to-end relay information is correlated into a single shared repository. The software also provides the first multimission latency calculator; previous latency calculations had been performed on a mission-by-mission basis.

Upload

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MRO relay telecom support of Mars Science Laboratory surface operations

IEEE Aerospace Conference (2014)

David M. Bell S. L. Allen Neil F. Chamberlain Monika Danos Chad Edwards

The Mars Science Laboratory (MSL) mission landed the Curiosity Rover on the surface of Mars on August 6, 2012, beginning a one Martian year primary science mission. The UHF relay link from Curiosity to the Mars Reconnaissance Orbiter (MRO) incorporates new features enabled by the Electra and Electra-Lite software-defined radios on MRO and Curiosity, respectively. Specifically, the Curiosity-MRO link has for the first time utilized frequency-agile operations, increased data rates from 256 kbps up to 2048 kbps, employed suppressed carrier modulation and a new Adaptive Data Rate algorithm in which the return-link data rate is varied to match the observed channel condition. During the first 200 sols, the telecom operations team has been able to tune the radio and protocol parameters to maximize return-link data volume, which is now averaging roughly 500 Mbits per sol or twice the design requirement of 250 Mbits per sol. The telecom team has also derived new predict models that reduce data volume prediction errors and that quantify the impact of operational modes and link parameters, providing further planning insight for MSL mission operations team.

Orbiter

Data link

Curiosity

Mars landing

10.1109/aero.2014.6836170

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Citations (15)

Spacecraft Position Determination with the Electra UHF Transceiver: A Comparison of One-Way and Two-Way Doppler Observations

IEEE Aerospace Conference (2024)

Harvey Elliott Todd Ely Austin Lazaro Eric Gustafson Ricardo Mendoza

In June 2022, the Electra Relay Operations team began conducting radiometric phase and power data collection during relay overflights of the InSight Lander by the ExoMars Trace Gas Orbiter (TGO). This mode of the Electra radio has potential applications for both navigation and radio science, but is relatively untested in flight. Here, we present both one-way (non-coherent) and two-way (coherent) Doppler observations conducted during 32 TGO relay overflights. Then we explore the ability to find the surface position of the lander with each data set and compare this against other methods.Looking forward to Mars Sample Return, the capability to do one-way Doppler tracking would be essential for monitoring the launch performance of the Mars Ascent Vehicle and determining the final trajectory of the Orbiting Sample container. Testing these positioning capabilities now will help us to prepare for that anticipated need.

Orbiter

Position (finance)

10.1109/aero58975.2024.10521197

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Mars 2020 Entry, Descent, and Landing as Observed by Radio Science Techniques at UHF and X-band Frequencies

2022 IEEE Aerospace Conference (AERO) (2022)

Dustin Buccino Kamal Oudrhiri Daniel Kahan Clement Lee E. Barbinis

On February 18, 2021, NASA's Mars 2020 Rover "Perseverance" conducted the Entry, Descent, and Landing (EDL) sequence to land safely on the surface of Mars at Jezero Crater. Due to the criticality of the EDL sequence, redundant telecommunications strategies were utilized to observe the event. The rover transmitted an X-band (8.4 GHz) signal encoded with Multiple Frequency Shift Keying tones direct-to-Earth and a UHF (401.5 MHz) signal with 8 kbps encoded telemetry to orbiters, which relayed the signal back to Earth at X-band. NASA's Deep Space Network complexes at Goldstone, California and Madrid, Spain received the direct-to-Earth X-band signal. Two of the largest steerable radio telescopes in the world, the 100-meter Green Bank Telescope in West Virginia and the Effelsberg 100-meter Radio Telescope in Germany also received the UHF carrier signal on Earth. During the EDL event, full spectrum recordings of the UHF and X-band signals were captured at these observatories using open-loop receivers. Real-time and post-processing signal analysis to determine power level, received frequency, and Doppler shift allowed determination of the spacecraft's health and safety state during critical sequences, including event detection such as atmospheric entry, plasma blackouts, and parachute deployment. Simultaneous observations of the UHF and X-band radio links allow for redundancy in the event of a fault and greatly improve confidence in Doppler event detection.

Descent (aeronautics)

Radio Science

10.1109/aero53065.2022.9843781

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Citations (1)

Sequence History Update Tool

Teerapat Khanampompan Roy E. Gladden Forest Fisher Chris DelGuercio

The Sequence History Update Tool performs Web-based sequence statistics archiving for Mars Reconnaissance Orbiter (MRO). Using a single UNIX command, the software takes advantage of sequencing conventions to automatically extract the needed statistics from multiple files. This information is then used to populate a PHP database, which is then seamlessly formatted into a dynamic Web page. This tool replaces a previous tedious and error-prone process of manually editing HTML code to construct a Web-based table. Because the tool manages all of the statistics gathering and file delivery to and from multiple data sources spread across multiple servers, there is also a considerable time and effort savings. With the use of The Sequence History Update Tool what previously took minutes is now done in less than 30 seconds, and now provides a more accurate archival record of the sequence commanding for MRO.

Sequence (biology)

File format

Table (database)

Sequence diagram

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