Incident: Kepler Space Observatory Reactor Wheel Failure Incident.

Published Date: 2013-05-16

Postmortem Analysis
Timeline 1. The software failure incident with the Kepler space observatory's reaction wheels failing happened as of the article's publication on May 16, 2013. [Article 18853]
System 1. Reaction wheels of the Kepler space observatory [18853].
Responsible Organization 1. Structural failure of the wheel bearing was responsible for causing the software failure incident on the Kepler space observatory [18853].
Impacted Organization 1. Kepler space observatory (NASA) [Article 18853]
Software Causes 1. Unknown
Non-software Causes 1. Structural failure of the wheel bearing [18853]
Impacts 1. The software failure incident resulted in the failure of two out of four reaction wheels on the Kepler space observatory, leading to the spacecraft being unable to be controlled and directed as before [Article 18853]. 2. As a consequence of the software failure, Kepler has been put in a resting state to minimize fuel use while NASA attempts to correct the problem, potentially halting its extended mission [Article 18853].
Preventions 1. Implementing more robust testing procedures during the development phase to catch any potential issues with the reaction wheels' software control [18853]. 2. Regularly monitoring and maintaining the software controlling the reaction wheels to detect any anomalies or potential failures before they escalate [18853].
Fixes 1. NASA is looking to gain back wheel functionality or determine if the observatory's thrusters could be used in conjunction with the working wheels to once again orient the spacecraft [18853].
References 1. NASA [Article 18853]

Software Taxonomy of Faults

Category Option Rationale
Recurring unknown Unknown
Phase (Design/Operation) design, operation (a) The software failure incident related to the design phase is evident in the article as it mentions serious technical issues affecting the Kepler space observatory. Specifically, the article highlights that two out of four reaction wheels used to point the spacecraft have failed, with NASA attributing this to a structural failure of the wheel bearing. This design flaw has led to Kepler being unable to be controlled and directed as before, impacting its functionality [Article 18853]. (b) The software failure incident related to the operation phase is also apparent in the article. NASA has put Kepler in a resting state to minimize fuel use while attempting to correct the problem caused by the failed reaction wheels. This operational response indicates that the failure is being managed through operational procedures to mitigate the impact on the spacecraft's functionality [Article 18853].
Boundary (Internal/External) within_system (a) The software failure incident related to the Kepler space observatory's technical issues, specifically the failure of two out of four reaction wheels, is within_system. The failure is attributed to a structural failure of the wheel bearing, which is an internal component of the spacecraft's system [18853]. NASA is working on correcting the problem internally by attempting to regain wheel functionality or exploring the use of thrusters in conjunction with the working wheels to orient the spacecraft [18853].
Nature (Human/Non-human) non-human_actions, unknown (a) The software failure incident related to non-human actions in this case is the failure of two out of four reaction wheels on the Kepler space observatory. NASA attributed this failure to a structural failure of the wheel bearing, which ultimately led to the spacecraft not being able to be controlled and directed as before [18853]. (b) The software failure incident related to human actions is not explicitly mentioned in the provided article.
Dimension (Hardware/Software) hardware (a) The software failure incident in the Kepler space observatory was attributed to a hardware issue, specifically a structural failure of the wheel bearing in the reaction wheels used to point the spacecraft [Article 18853]. This hardware failure led to the loss of control and direction of the spacecraft, impacting its ability to function as intended. (b) There is no mention in the article of the software failure incident being caused by contributing factors originating in software.
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident described in the article is non-malicious. The failure was attributed to a structural failure of the wheel bearing in the reaction wheels of the Kepler space observatory, leading to a loss of control over the spacecraft's orientation [18853]. NASA is working to address the technical issues to potentially restore functionality to the observatory, indicating that the failure was not caused by malicious intent but rather by a technical fault.
Intent (Poor/Accidental Decisions) unknown The article does not mention any software failure incident related to poor decisions or accidental decisions. Therefore, the intent of the software failure incident in the Kepler space observatory incident is unknown.
Capability (Incompetence/Accidental) unknown The article does not mention any software failure incident related to development incompetence or accidental factors. Therefore, the information to answer this question is 'unknown'.
Duration temporary The software failure incident related to the Kepler space observatory's reaction wheels can be categorized as a temporary failure. The article mentions that two out of four reaction wheels have failed due to a structural failure of the wheel bearing. NASA has put Kepler in a resting state to minimize fuel use while attempting to correct the problem, indicating efforts to address the issue and potentially restore functionality [18853].
Behaviour crash, other (a) crash: The software failure incident in the Kepler space observatory article can be categorized as a crash. The article mentions that two out of four reaction wheels used to point the spacecraft have failed, leading to the spacecraft being unable to be controlled and directed as before. This loss of control and functionality can be considered a crash in the context of the spacecraft's software system [18853]. (b) omission: There is no specific mention of the software failure incident being related to the system omitting to perform its intended functions at an instance(s) in the article [18853]. (c) timing: The software failure incident in the Kepler space observatory article does not relate to the system performing its intended functions correctly but too late or too early [18853]. (d) value: The software failure incident in the Kepler space observatory article does not relate to the system performing its intended functions incorrectly [18853]. (e) byzantine: The software failure incident in the Kepler space observatory article does not relate to the system behaving erroneously with inconsistent responses and interactions [18853]. (f) other: The behavior of the software failure incident in the Kepler space observatory article can be categorized as a loss of control and functionality due to the failure of critical components (reaction wheels) in the spacecraft's software system, leading to the spacecraft being put in a resting state to minimize fuel use while NASA attempts to correct the problem. This behavior could be classified as a critical failure impacting the system's core functionality [18853].

IoT System Layer

Layer Option Rationale
Perception None None
Communication None None
Application None None

Other Details

Category Option Rationale
Consequence non-human, theoretical_consequence The consequence of the software failure incident described in the article is primarily related to the potential impact on the Kepler space observatory's mission due to technical issues with its reaction wheels. The failure of two out of four reaction wheels has led to a situation where Kepler can't be controlled and directed as before, potentially halting its mission. NASA is working to address the issue by attempting to regain wheel functionality or exploring alternative methods to orient the spacecraft [18853]. Therefore, the relevant option for the consequence of the software failure incident in this case is (h) theoretical_consequence, as the potential consequence of the software failure impacting the Kepler space observatory's mission is being discussed, but no definitive outcome has been determined yet.
Domain knowledge (a) The failed system, the Kepler space observatory, was intended to support the industry of knowledge, specifically space exploration. The observatory was launched in 2009 and has been instrumental in discovering new planetary systems and potentially life-supporting planets [Article 18853].

Sources

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