Incident: Schiaparelli Mars Landing Failure: Software Error Causes Crash on Mars

Published Date: 2017-05-24

Postmortem Analysis
Timeline 1. The software failure incident with the European Space Agency (Esa) probe Schiaparelli crashing on Mars happened on 19 October last year [59626]. Therefore, the incident occurred in October 2016.
System 1. Inertial Measurement Unit (IMU) in the craft tracking spin rate [59626] 2. Guidance, navigation, and control system software [59626]
Responsible Organization 1. The unexpected high rotation causing saturation of an instrument in the craft tracking spin rate was responsible for the software failure incident [59626].
Impacted Organization 1. The European Space Agency (ESA) [Article 59626]
Software Causes 1. Unexpected high rotation causing saturation of an instrument in the craft tracking spin rate. 2. Exceeding the programmed measurement range in the Inertial Measurement Unit leading to a major altitude error in the guidance, navigation, and control system software. 3. The software incorrectly determining the probe's altitude, leading to premature release of the parachute and back shell, and firing the landing thrusters for only three seconds instead of 30 [59626].
Non-software Causes 1. Unexpected high rotation causing saturation of an instrument in the craft tracking spin rate [59626] 2. Exceeding the programmed measurement range in the Inertial Measurement Unit 3. Major altitude error in the guidance, navigation, and control system software due to the knock-on effect of the unexpected input
Impacts 1. The software failure incident caused the European Space Agency (Esa) probe Schiaparelli to crash land on Mars at a high speed of 540km/h (335mph) due to a major altitude error in the guidance, navigation, and control system software [59626]. 2. The software failure led to the premature release of the parachute and back shell, as well as a shortened firing of the landing thrusters, resulting in the probe's destruction [59626]. 3. The incident highlighted areas that required more attention in the preparation, validation, and verification of the entry, descent, and landing system, impacting the overall mission success and safety [59626]. 4. The software failure incident provided valuable lessons for future missions, particularly the ExoMars 2020 mission, emphasizing the importance of addressing weak spots and ensuring thorough testing and validation of software systems [59626].
Preventions 1. Proper validation and verification of the entry, descent, and landing system software could have prevented the incident [59626]. 2. Ensuring the software had robust error handling mechanisms to handle unexpected inputs, such as the high rotation causing saturation of an instrument in the craft tracking spin rate, could have helped prevent the failure [59626]. 3. Conducting thorough testing and simulations to identify and address weak spots in the software that contributed to the mishap could have prevented the incident [59626].
Fixes 1. Conduct a thorough review and update of the preparation, validation, and verification processes for the entry, descent, and landing system software to ensure all potential failure points are addressed [59626]. 2. Implement additional testing and simulations to account for unexpected inputs and potential saturation of instruments in the craft tracking systems [59626]. 3. Enhance the software's error handling mechanisms to prevent major altitude errors in the guidance, navigation, and control system in case of unexpected events [59626]. 4. Improve the software's decision-making logic to prevent premature actions such as releasing the parachute and firing landing thrusters based on incorrect altitude readings [59626].
References 1. European Space Agency (ESA) officials [59626]

Software Taxonomy of Faults

Category Option Rationale
Recurring unknown (a) The software failure incident related to the crash landing of the European Space Agency (Esa) probe Schiaparelli on Mars due to an unexpected high rotation causing a major altitude error in the guidance, navigation, and control system software has not been explicitly mentioned to have happened again within the same organization or with its products and services [59626]. (b) The software failure incident related to the crash landing of the Esa probe Schiaparelli on Mars due to an unexpected high rotation causing a major altitude error in the guidance, navigation, and control system software has not been explicitly mentioned to have happened again at other organizations or with their products and services [59626].
Phase (Design/Operation) design (a) The software failure incident related to the design phase is evident in the article. The incident with the European Space Agency (Esa) probe Schiaparelli crashing on Mars was attributed to unexpected high rotation causing saturation of an instrument in the craft tracking spin rate. This unexpected input to the Inertial Measurement Unit, exceeding the programmed measurement range, had a knock-on effect that caused a major altitude error in the guidance, navigation, and control system software. The probe's computer mistakenly determined it was below ground level when it was actually still two miles up, leading to premature actions like releasing the parachute and firing the landing thrusters for only three seconds instead of 30. This highlights a failure in the design phase where certain areas should have been given more attention in the preparation, validation, and verification of the entry, descent, and landing system [59626]. (b) The software failure incident related to the operation phase is not explicitly mentioned in the provided article.
Boundary (Internal/External) within_system (a) within_system: The software failure incident involving the crash landing of the Schiaparelli probe on Mars was primarily attributed to factors originating from within the system. Specifically, the incident was caused by an unexpected high rotation leading to saturation of an instrument in the craft tracking spin rate, which in turn caused a major altitude error in the guidance, navigation, and control system software [59626]. (b) outside_system: There is no explicit mention in the provided article about contributing factors originating from outside the system that led to the software failure incident.
Nature (Human/Non-human) non-human_actions, human_actions (a) The software failure incident in the Schiaparelli probe crash landing on Mars was primarily due to non-human actions. The incident was caused by an unexpected high rotation leading to saturation of an instrument in the craft, which then resulted in a major altitude error in the guidance, navigation, and control system software. This unexpected input to the Inertial Measurement Unit exceeded the programmed measurement range, causing the probe to miscalculate its altitude and release its parachute and back shell prematurely, ultimately leading to the crash landing [Article 59626]. (b) While human actions were involved in the preparation, validation, and verification of the entry, descent, and landing system, the software failure incident itself was primarily attributed to non-human actions as described above. The investigation highlighted areas that should have been given more attention in the preparation process, emphasizing the need for improved validation and verification processes for future missions [Article 59626].
Dimension (Hardware/Software) hardware, software (a) The software failure incident in the Schiaparelli probe crash on Mars was primarily attributed to a hardware-related issue. The incident was caused by an unexpected high rotation leading to saturation of an instrument in the craft, which then resulted in a major altitude error in the guidance, navigation, and control system software [59626]. (b) The software failure incident also had contributing factors originating in software. The unexpected input to the Inertial Measurement Unit, which exceeded the programmed measurement range, had a knock-on effect on the software, causing a major altitude error in the guidance, navigation, and control system software. This error led to the probe releasing its parachute and firing its landing thrusters prematurely, ultimately resulting in the crash landing on Mars [59626].
Objective (Malicious/Non-malicious) non-malicious (a) The software failure incident related to the crash landing of the Schiaparelli probe on Mars was non-malicious. The incident was caused by an unexpected high rotation leading to saturation of an instrument in the craft, which then caused a major altitude error in the guidance, navigation, and control system software. This resulted in the probe releasing its parachute and firing its landing thrusters prematurely, ultimately leading to its destruction [59626].
Intent (Poor/Accidental Decisions) poor_decisions, accidental_decisions (a) The software failure incident related to the crash landing of the Schiaparelli probe on Mars was primarily due to poor decisions made during the preparation, validation, and verification of the entry, descent, and landing system software. The incident was caused by an unexpected high rotation leading to saturation of an instrument, which in turn caused a major altitude error in the guidance, navigation, and control system software. This error resulted in the probe releasing its parachute and firing its landing thrusters prematurely, ultimately leading to the probe's destruction [59626]. (b) Additionally, the incident also involved accidental decisions or unintended consequences resulting from the software failure. The unexpected input to the Inertial Measurement Unit exceeded the programmed measurement range, causing a chain reaction of events that led to the probe's misguided actions during descent. The probe's computer mistakenly determined it was below ground level when it was actually still two miles above the surface, leading to incorrect actions such as premature parachute release and shortened thruster firing duration [59626].
Capability (Incompetence/Accidental) development_incompetence (a) The software failure incident related to development incompetence is evident in the article. The investigation into the crash landing of the Schiaparelli probe on Mars revealed that there were areas that should have been given more attention in the preparation, validation, and verification of the entry, descent, and landing system. Esa's director of human spaceflight and exploration, David Parker, acknowledged that there were weak spots that contributed to the mishap, indicating a lack of professional competence in certain aspects of the software development process [59626]. (b) The software failure incident was not attributed to accidental factors but rather to specific issues in the preparation and validation of the entry, descent, and landing system. The unexpected high rotation and saturation of an instrument in the craft tracking spin rate were identified as key factors that led to the major altitude error in the guidance, navigation, and control system software, ultimately causing the probe to crash land on Mars. The probe's computer misinterpreted its altitude due to these issues, leading to premature actions such as releasing the parachute and firing the landing thrusters for a shorter duration than intended [59626].
Duration permanent (a) The software failure incident in the article was more of a permanent nature. The incident was caused by unexpected high rotation leading to saturation of an instrument in the craft's software, which then caused a major altitude error in the guidance, navigation, and control system software. This error ultimately led to the probe crashing on Mars. The investigation highlighted that there were multiple areas that should have been given more attention in the preparation, validation, and verification of the entry, descent, and landing system, indicating a more permanent failure due to contributing factors introduced by all circumstances [59626]. (b) The software failure incident in the article does not align with a temporary nature. The incident was not a momentary glitch or error but rather a cascading effect of the unexpected input to the Inertial Measurement Unit, which had a lasting impact on the probe's descent and landing process, ultimately leading to the crash landing on Mars. The investigation emphasized the need for learning lessons and addressing weak spots for future missions, indicating a more permanent failure due to contributing factors introduced by all circumstances [59626].
Behaviour crash, value (a) The software failure incident in Article 59626 resulted in a crash. The European Space Agency (Esa) probe Schiaparelli crashed on Mars due to a major altitude error in the guidance, navigation, and control system software. The software erroneously determined the probe was below ground level when it was actually still two miles up, leading to the premature release of the parachute and back shell, and firing the landing thrusters for only three seconds instead of 30, causing the probe to hit the surface at a high speed of 540km/h (335mph) [59626]. (f) In addition to the crash, the software failure incident in Article 59626 also exhibited other behaviors. The incident was caused by an unexpected high rotation that saturated an instrument in the craft, leading to a knock-on effect that caused the major altitude error. This unexpected input exceeded the programmed measurement range and had a cascading impact on the probe's descent and landing sequence, ultimately resulting in the crash landing on Mars. The incident highlighted areas that required more attention in the preparation, validation, and verification of the entry, descent, and landing system software for future missions [59626].

IoT System Layer

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

Other Details

Category Option Rationale
Consequence non-human (a) death: People lost their lives due to the software failure - The software failure incident involving the European Space Agency (Esa) probe Schiaparelli crashing on Mars did not result in any loss of life. The probe itself was destroyed upon impact, but there were no human casualties mentioned in the article [59626].
Domain knowledge (a) The failed system was intended to support the knowledge industry, specifically space exploration. The software failure incident occurred with the European Space Agency (Esa) probe Schiaparelli during its landing on Mars as part of the ExoMars mission [59626]. The probe was designed to test the combined parachute and retro-rocket landing system for a rover mission aimed at searching for signs of life on the Red Planet [59626]. The incident highlighted the challenges and critical nature of landing on Mars, emphasizing the importance of thorough preparation, validation, and verification in space exploration missions [59626].

Sources

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