November 2, 2020

AMA Celebrates the 20th Anniversary of the International Space Station

The International Space Station (ISS) has changed dramatically from its very earliest module—a functional cargo block originally named Zarya, in Russian meaning dawn for being first—and evolved through many iterations before becoming the ISS known today. Whereas the 42-foot Zarya served to provide electrical power and propulsion during initial assembly stages, today’s ISS is the largest structure ever built in space and, with its multiple modules for specialized functions, is now over two football fields long and shines second only to Earth’s Moon in the night sky.

From those storied beginnings, and through each decade as the technologies advanced right up to present-day undertakings, Analytical Mechanics Associates (AMA) has been there every step of the way. AMA’s walk with the cosmic stepping-stone includes contributions to those very first modules with engineering and simulation expertise, supporting payload missions and carrying experiments safely to and from since, and delivering important news about ISS activities on television and online today.

Integrating Algorithms First

AMA’s earliest intersection in the ISS journey began in the late 1980s, when Renji Kumar (now AMA CEO Emeritus) worked alongside other AMA colleagues at NASA’s Langley Research Center in the Space Station Freedom Office. The work entailed integrating ISS attitude control algorithms using control moment gyroscopes (CMGs) into the Langley ISS simulation environment IDEAS2, (Initial Design and Evaluation Analysis System) and simulating the attitude behavior of several ISS configurations under varying environmental conditions. What made this work interesting was the complex simulation environment and the time-varying aspect of the ISS configuration. For example, when a visiting vehicle like the space shuttle docks or berths to the ISS, the mass properties of the entire system changed and the attitude control algorithm had to be able to adapt and adjust to keep the ISS and the space shuttle stack oriented properly.

Additionally, the ISS would lose altitude over time due to atmospheric drag and the vehicle had to be reboosted periodically. These orbit maintenance maneuvers were performed by thrusters as part of the ISS reaction control system (RCS). While the ISS was being reboosted, the attitude control would transition from the CMGs to RCS attitude control thrusters. Moreover, the thrusters could cause plume impingement on the ISS solar arrays. All these scenarios were simulated, and the results were used periodically for “what-if” studies as well as for independent verification and validation (IV&V) for the primary ISS missions.

Moreover, given the lightweight nature of the solar arrays, we also performed control structure interaction studies to ensure proper dynamic behavior when the solar array “alpha” joint controller would turn the arrays for required pointing.

Simulation Software


AMA’s simulation capabilities continued to support the ISS beyond the ‘90s with the development of the Synergistic Engineering Environment (SEE) and then the Exploration Visualization Environment (EVE) software systems. These systems are cross-platform simulation, visualization, and analysis systems designed to integrate engineering data with a virtual environment in support of the design and planning of aerospace missions. The SEE was used at NASA’s Johnson Space Center, Langley, and by commercial groups for engineering analysis and mission planning.

Simulations have been used to support early configuration-build sequence planning, ISS operations visualizations, and payload instrumentation operations simulations.

SEE was used by the mission operations team at Johnson to visualize the 28-day planning cycle of ISS operations each week. The ISS team’s simulation would calculate what the station would be doing during for the next month (array movements, reorientations, thruster firings, etc.). The SEE would be used to import ISS data to visualize the planned ISS operations. This was then used by the ISS team to aid in analysis and situational awareness looking for any potential issues in resultant plans.

Snapshot of an ISS/orbiter docking scenario with thruster firings in the SEE.

Work was also done with the Vehicle Integrated Performance and Environmental Resources (VIPER) engineering team at Johnson and with engineering teams at Langley during early planning and contingency analysis efforts of the ISS. The SEE was used to visualize various configurations of the ISS and what-if scenarios of the ISS assembly sequence build up. The software was also used to help the engineering teams visualize and understand the various docking scenarios and robotic arm maneuvers needed during assembly buildup and payload operations. This type of analysis was used early on when NASA was looking at commercial launches.

SEE and EVE have been used to support various scientific instrument payloads of the ISS due to these software systems’ ability to combine ISS operations with anticipated payload operations. Once such instrument was the SAGE III, which makes measurements during solar and lunar occultation, looking at light from the Sun or the Moon while passing through Earth’s atmosphere at the edge, or limb, of the planet. SAGE I and II had been on satellites previously, so asking and answering how the operations and movements of different aspects of the station would impact the collection of data was essential. In the early planning phases of the SAGE III instrument, SEE software provided simulations of the ISS and how it might impact operations of the instrument. The orbital path of the space station helps provide repeated SAGE III observations, as well as creating some obstacles that AMA simulations could demonstrate for the SAGE III team. 

SEE (precursor to EVE) software simulating the environmental operations of the SAGE instrument on ISS before ISS was built.

SAGE III was successfully added to the ISS in 2017 and the first set of atmospheric data collected was released publicly in 2018. EVE continues to be used by various engineering teams to analyze and visualize payload operations that are proposed for use on the ISS.

Payload Operations and Configuration Management

The ISS has continually proven to be a place to help us understand the effects of microgravity on humans, and a home for world class scientific experiments. AMA also supported ISS payload operations

AMA configuration management team and astronaut Shane Kimbrough (third from left) stand below mission plaques inside the Payload Operations Integration Center at NASA’s Marshall Space Flight Center.

From 2012 to 2018, the AMA team in Huntsville worked with the Huntsville Operation Support Center providing integration and evaluation for Certificates of Flight Readiness. Supporting the payload operations director, AMA enabled science experiments to reach the space station as well as planning for and scheduling crew entry and exits. In recognition of outstanding work supporting the ISS mission operations and integration contract, the AMA configuration management team was honored with a request to participate in the traditional plaque-hanging ceremony upon the close of the 50th expedition in 2017.

Currently, AMA is working with payloads that leave the station…and burn up! Spacecraft Fire Safety (Saffire) experiments via NASA’s Glenn Research Center are carried in the Cygnus spacecraft. 

Cygnus is launched to the space station primarily to resupply consumables (food, etc.) for the astronauts. After unloading the consumables, the astronauts pack Cygnus with trash and release it to burn up in the atmosphere. Where the Saffire experiments come into play is after release, but before Cygnus is destroyed in the atmosphere. A set of fire experiments are run in low gravity to see how various materials burn in space.

Live Television, Multimedia, and Communications

The live television team chronicles every dynamic event involving the space station, including expedition crew rotations entailing launches from Russia, docking, hatch opening, VIP welcoming ceremonies, undocking, and landing in Kazakhstan. Producers support from Russia all the crew

preflight activities, producing videos and working logistics necessary to stream those videos back to Johnson for inclusion into NASA TV Video File productions. In October 2020, AMA’s live television crew broadcasted the most recent docking of the Cygnus supply ship, which coincidentally was carrying Saffire experiments. The live team also supports multiple media and education client interviews with the in-orbit crew every week, including celebrity engagement events like Dwayne “The Rock” Johnson for Instagram Live, and various VIPs such as the office of the President of the United States,

Television coverage provided by AMA at JSC of Cygnus payload craft docking with ISS on October 5, 2020. Credit: NASA Video.

Vice President of the United States, and other international heads of state from partnered countries to the ISS.

Producer Beth Weissinger supporting the Expedition 56/57 Crew Pre-Launch Crew Activities Video File feed from Russia – Oct. 2020.

The multimedia team supports the ISS program by producing video shoots interviewing astronauts, scientists, engineers, and program managers from ISS, as well as field shoots capturing crew training, and crew return. A variety of videos are produced to tell the story of ISS: educational explainer videos, weekly ISS update videos (Space to Ground), weekly video highlight reels (Space Cast Weekly), EVA Overview videos, crew profiles, educational demonstration videos (“STEMonstrations”), and more. The communication strategy team works with the NASA customer to develop communication plans and campaigns, and to effectively promote the external messaging and outreach goals of the ISS.

Working with museums across the country to develop partnerships, the team provides outreach multimedia resources to increase awareness of the ISS mission. Through the Destination Station program, the team travels with NASA astronauts, engineers, and scientists to locations across the country to engage with the public.

Webinars are produced for students that provide opportunities to learn about the science being conducted on board the station as well as some of the challenges of living for long periods in low-Earth orbit.

AMA continues to look forward to what the ISS will teach everyone in the years to come, and wishes the thousands of people who have contributed to this amazing feat of human innovation and cooperation a happy 20th anniversary!

Inflight event with PBS SciGirls program. Credit: NASA Video.

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