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ISS Testbed for Analog Research Communication Delay Preparation (I-STAR Comm Delay Preparation) (I-STAR_Comm_Delay_Preparation)


Overview | Description | Applications | Operations | Results | Publications | Imagery

Experiment Overview

This content was provided by David Korth, and is maintained in a database by the ISS Program Science Office.

Brief Summary

The ISS Testbed for Analog Research Communication Delay Preparation (ISTAR Comm Delay Preparation) investigation, an Exploration Detailed Test Objective (xDTO), examines how mission operations can be optimized in the presence of speed-of-light communication delays of up to tens of minutes. Present human space missions rely upon fast and almost continuous voice, data, command, and telemetry transmissions between crew and ground, a model that cannot succeed for exploration missions to Mars, near-Earth asteroids, or other targets in deep space. This investigation explores two ways to lessen the impact of delayed communication: first, providing the crew with revised written work instructions ("procedures") that give them extra information they need to complete a job--and solve any problems that may arise while they do it, without having to call Mission Control as they do today; and second, supplementing voice calls between the crew and Mission Control with text messaging, a popular and intuitive method of communicating with variable delay which has proved its value in ground-based exploration mission simulations employing delayed communication and which is ready to be tested in space.

Principal Investigator(s)

  • David Korth, Johnson Space Center , Houston, TX, United States
  • Co-Investigator(s)/Collaborator(s)

    Information Pending

    Information Pending

    Sponsoring Space Agency

    National Aeronautics and Space Administration (NASA)

    Sponsoring Organization

    Human Exploration and Operations Mission Directorate (HEOMD)

    ISS Expedition Duration

    May 2012 - September 2012

    Expeditions Assigned


    Previous ISS Missions

    Information Pending

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    Experiment Description

    Research Overview

    • ISTAR Comm Delay Preparation is the first in a series of investigations exploring delayed voice communication and modified flight and ground operational procedures in preparation for the future human exploration of deep space.

    • The initial International Space Station (ISS) tests, planned for Increments 31 through 34, include a United States On-orbit Segment (USOS) crewmember and the Houston Flight Control Team.

    • Aim 1: To make and evaluate changes to current operational procedures, which rely on significant interaction between the crew and the Flight Control Team, to allow the crew to work more autonomously.

    • Aim 2: To develop operational protocols for text messaging between the ISS crew and Mission Control Center (MCC), and to evaluate text messaging as a supplement to delayed voice communication. This work is done in parallel with continued exploration of communication delay in ground-based space exploration analogs such as Desert Research and Technology Studies (DRATS) and NASA Extreme Environment Mission Operations (NEEMO).

    • Aim 3: To prepare crews and flight control teams with skills and operational techniques needed for future deep space exploration missions with reduced communication and increased crew autonomy.

    • Aim 4: To test, refine, and formally adopt the procedural and communication tools that are needed for future tests with formally delayed voice, data, or both, removing variables that could potentially confound an evaluation of the effects of the communication delay itself.


    To facilitate a planned full clinical study of communication delay (JSC-HRP-076) in the Increment 35 and 36 timeframe, ISTAR Comm Delay Preparation enlists crews and flight controllers to identify, modify, and evaluate a selection of crew procedures for increased crew autonomy, and to investigate text messaging as a supplement for restricted voice communication. This activity eliminates those two factors as potentially confounding variables in future evaluations of the effects of delayed communication. This investigation also provides valuable tests of the modified procedures and the messaging concept themselves.

    a. Autonomous Crew Procedure Development and Execution: Delayed communication forces mission crews and their vehicles to be more autonomous. Crews must learn to do their work without the (often instantaneous) outside assistance currently available from Mission Control. Procedure owners also bear part of the burden of autonomous operations: they must learn how to write procedures that do not require calls to Mission Control and that contain enough extra information so that crews can perform them with no outside help. The procedure owners must also develop methods to train crewmembers to operate autonomously. Crews and flight controllers involved in this investigation gain valuable insight into how communication delay drives the design, construction, and operation of hardware and software for future deep-space systems.

    b. Text Messaging Evaluation: Past and present ground-based simulated deep-space exploration missions such as DRATS and NEEMO include delayed voice and data communication. Operators in those tests report that text messaging is an effective supplement for delayed or restricted voice communication. The objective of this investigation is to evaluate text messaging in a real space-flight operational environment with restricted voice communication. The results, in combination with past and ongoing work in DRATS, NEEMO, and other space flight analogs, inform future operational use of text messaging when voice is ineffective.

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    Space Applications

    This xDTO is the first of several investigations to learn how crews on the way to Mars or a near-Earth asteroid can best conduct mission operations in the presence of significant speed-of-light communications delays. The operational techniques that crews and flight controllers use in human spaceflight today depend on prompt and responsive radio communication. New operational tools and techniques to be investigated in this and future related studies are crucial to the success of future human exploration of deep space.

    Earth Applications


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    Operational Requirements

    The crew performs the autonomous crew procedure test while completing routine work they do on ISS as part of normal operations. On average, each USOS crewmember performs one autonomous procedure per month. The day's schedule includes time for procedure review before the task begins, and time for a debrief with MCC after the procedure is complete. The schedule also allows some extra time in case the crew runs into a problem and has to read more background information or perform extra procedure steps. In addition to the crew debrief, ground operators complete a debrief form after each autonomous procedure.

    The text messaging test enlists each USOS crewmember for an average of one working afternoon per month and includes normally scheduled tasks that require at least moderate interaction between crew and ground. Operations planners schedule the test period so that it does not include tasks of a critical nature or tasks that need direct voice communication for crew or vehicle safety. The crew participants do not call MCC on the radio during the test. Instead, they use a text messaging application. In MCC, the Capcom uses the same application to reply to the crew, and the Flight Director and other flight controllers are able to read the messages to and from the crew just as they listen to space-to-ground voice communications today. As with the autonomous procedure tests, the schedule reserves time for a debrief after the work period. It also includes extra time for the crew to type and read text, which may take longer than speaking and listening on the radio. Ground operators involved in the test also complete debrief forms afterward.

    Operational Protocols

    For autonomous crew procedure tests, the crew performs procedures that the responsible flight control teams have specifically modified for crew autonomy. For text messaging tests, participating crewmembers conduct their nominal ISS tasks during each xDTO test day, using text instead of voice to communicate with MCC. The ISTAR team has established test wave-off criteria in case an emergency occurs on ISS, a higher-priority activity must replace the scheduled test, the crew falls far behind the timeline, the crew becomes concerned about damaging Station hardware, or there is another valid reason to terminate the test.

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    Results/More Information

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    Related Websites
  • Analog Missions and Field Testing
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    Information provided by the investigation team to the ISS Program Scientist's Office.
    If updates are needed to the summary please contact JSC-ISS-Program-Science-Group. For other general questions regarding space station research and technology, please feel free to call our help line at 281-244-6187 or e-mail at JSC-ISS-Payloads-Helpline.