Incident: Opportunity Rover's Flash Memory Failure on Mars.

Published Date: 2014-09-01

Postmortem Analysis
Timeline 1. The software failure incident with the Opportunity rover's memory began to occur before September 2014 as per the article published on September 1, 2014 [28964].
System 1. Flash memory system of the Opportunity rover [28964]
Responsible Organization 1. The software failure incident on the Opportunity rover on Mars was caused by worn-out cells in the flash memory, leading to an increasing frequency of computer resets [28964].
Impacted Organization 1. NASA's Opportunity rover [28964]
Software Causes 1. Worn-out cells in the flash memory causing an increasing frequency of computer resets [28964] 2. Flash memory sector wear out from repeated use leading to resets interfering with planned science activities [28964]
Non-software Causes 1. Wear and tear of individual cells within the flash memory sector due to repeated use [28964] 2. Worn-out cells in the flash memory causing an increasing frequency of computer resets [28964] 3. Flash memory retaining data even when power is off, leading to potential wear-out of cells [28964]
Impacts 1. The software failure incident on the Opportunity rover's memory caused an increasing frequency of computer resets, including a dozen resets in a month, which interfered with the rover's planned science activities [28964]. 2. The resets were suspected to be caused by worn-out cells in the flash memory, leading to the decision to reformat the rover's flash memory to address the issue [28964]. 3. The project had to reformat the flash memory on the Spirit rover five years prior to the incident on Opportunity to stop a series of amnesia events Spirit had been experiencing, indicating a similar software failure issue [28964].
Preventions 1. Regular maintenance and monitoring of the flash memory to detect early signs of wear and prevent complete failure [28964]. 2. Implementing a more robust error-handling mechanism to prevent frequent computer resets that interfere with planned activities [28964]. 3. Conducting periodic software updates and optimizations to improve the overall performance and stability of the rover's memory system [28964].
Fixes 1. Reformatting the rover's flash memory to clear out worn-out cells and avoid further resets [28964].
References 1. NASA's Jet Propulsion Laboratory, Pasadena, California [28964] 2. John Callas, project manager for NASA's Mars Exploration Rover Project [28964]

Software Taxonomy of Faults

Category Option Rationale
Recurring one_organization, unknown (a) The software failure incident related to the Opportunity rover's memory beginning to fail is not the first time such an issue has occurred within NASA's projects. The article mentions that NASA's other rovers, specifically the Spirit rover, had similar problems in the past. The project reformatted the flash memory on Spirit five years ago to address a series of amnesia events it was experiencing [28964]. (b) The article does not provide specific information about similar software failure incidents happening at other organizations or with their products and services.
Phase (Design/Operation) design, operation (a) The software failure incident related to the design phase can be seen in the case of the Opportunity rover on Mars. The article mentions that the rover's memory is beginning to fail, leading to an increasing frequency of computer resets. This issue is suspected to be caused by worn-out cells in the flash memory, which is a design-related problem as individual cells within a flash memory sector can wear out from repeated use [28964]. (b) The software failure incident related to the operation phase is evident in the disruptions caused by the computer resets on the Opportunity rover. The resets interfere with the rover's planned science activities, even though recovery from each incident is completed within a day or two. This indicates that the failure is due to contributing factors introduced by the operation or misuse of the system [28964].
Boundary (Internal/External) within_system (a) The software failure incident related to the Opportunity rover's memory beginning to fail is within the system boundary. The article mentions that the increasing frequency of computer resets prompted the rover team to plan to reformat the rover's flash memory [28964]. This indicates that the failure is due to factors originating from within the system itself, specifically the wear-out of individual cells within the flash memory sector from repeated use.
Nature (Human/Non-human) non-human_actions (a) The software failure incident occurring due to non-human actions: The software failure incident with the Opportunity rover on Mars was primarily attributed to worn-out cells in the flash memory causing an increasing frequency of computer resets. This issue was identified as the leading suspect in causing the resets, prompting the rover team to plan to reformat the rover's flash memory to address the problem [28964]. (b) The software failure incident occurring due to human actions: There is no specific mention in the provided article about the software failure incident being caused by human actions.
Dimension (Hardware/Software) hardware (a) The software failure incident occurring due to hardware: - The Opportunity rover's memory is beginning to fail, specifically the flash memory used for storing data [28964]. - Individual cells within the flash memory sector can wear out from repeated use, leading to an increasing frequency of computer resets [28964]. - The worn-out cells in the flash memory are suspected to be causing the resets, prompting the need for reformatting to identify bad cells and avoid them [28964]. (b) The software failure incident occurring due to software: - The resets and memory failures are attributed to the flash memory hardware wearing out from repeated use, indicating a hardware-related issue rather than a software-specific failure [28964].
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident related to the Opportunity rover on Mars was non-malicious. The failure was due to the rover's flash memory beginning to fail, causing an increasing frequency of computer resets. The operators planned to wipe and reformat the rover's flash memory to fix the bugs and restore the rover's functionality [28964].
Intent (Poor/Accidental Decisions) unknown The articles do not provide information about a software failure incident related to poor_decisions or accidental_decisions.
Capability (Incompetence/Accidental) accidental (a) The software failure incident related to development incompetence is not mentioned in the provided article [28964]. (b) The software failure incident related to accidental factors is evident in the article [28964] where it discusses the Opportunity rover's memory beginning to fail due to worn-out cells in the flash memory sector. The increasing frequency of computer resets prompted the rover team to plan to reformat the flash memory to address the issue. This failure is attributed to the accidental wearing out of individual cells within the flash memory sector from repeated use.
Duration permanent, temporary (a) The software failure incident related to the Opportunity rover's memory beginning to fail is more of a permanent issue. The article mentions that the rover's memory is failing, causing an increasing frequency of computer resets, which interfere with the rover's planned science activities [28964]. The operators plan to wipe the memory completely in a bid to fix the bugs and restore the rover to its sprightly best. This indicates that the failure is not just a one-time occurrence but a persistent issue that requires a complete memory reset to address the underlying problems. (b) The software failure incident can also be considered temporary to some extent. Although the resets caused by the failing memory interfere with the rover's planned science activities, the recovery from each incident is completed within a day or two [28964]. This suggests that while the failure is causing disruptions, the rover is able to recover relatively quickly from these temporary setbacks.
Behaviour crash, other (a) crash: The software failure incident in the article is related to the Opportunity rover's memory beginning to fail, leading to an increasing frequency of computer resets. These resets interfere with the rover's planned science activities, even though recovery from each incident is completed within a day or two [28964]. (b) omission: The software failure incident does not specifically mention any instances of the system omitting to perform its intended functions. The focus is more on the memory failure causing computer resets rather than the system omitting functions [28964]. (c) timing: The software failure incident does not relate to the system performing its intended functions too late or too early. The primary issue is the memory failure causing frequent resets, impacting the rover's planned activities [28964]. (d) value: The software failure incident does not involve the system performing its intended functions incorrectly. The main concern is the memory failure leading to computer resets, affecting the rover's scientific operations [28964]. (e) byzantine: The software failure incident does not exhibit the system behaving erroneously with inconsistent responses and interactions. The primary issue is the memory failure causing frequent resets, which are promptly recovered from by the rover team [28964]. (f) other: The software failure incident is primarily characterized by the memory failure in the Opportunity rover, leading to an increasing frequency of computer resets that disrupt planned science activities. The solution involves reformatting the flash memory to address the worn-out cells causing the resets [28964].

IoT System Layer

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

Other Details

Category Option Rationale
Consequence no_consequence (a) death: People lost their lives due to the software failure (b) harm: People were physically harmed due to the software failure (c) basic: People's access to food or shelter was impacted because of the software failure (d) property: People's material goods, money, or data was impacted due to the software failure (e) delay: People had to postpone an activity due to the software failure (f) non-human: Non-human entities were impacted due to the software failure (g) no_consequence: There were no real observed consequences of the software failure (h) theoretical_consequence: There were potential consequences discussed of the software failure that did not occur (i) other: Was there consequence(s) of the software failure not described in the (a to h) options? What is the other consequence(s)? The articles do not mention any of the consequences (a) to (i) related to the software failure incident with the Opportunity rover on Mars.
Domain knowledge (a) The failed system was related to the industry of space exploration, specifically the Mars Exploration Rover Project by NASA. The Opportunity rover, which experienced memory failures, was part of this project aimed at exploring Mars [28964].

Sources

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