I pulled a list of "recent" (post-Cold War ish) payload fairing separation failures, which surprised me. I expected more. Did I miss any?
Question to our very knowledgeable cohort:What other fairings are ejected during coast?Falcon drops the fairings during second stage burn with the vehicle accelerating.Atlas V 4x1 does the same AIUI.Atlas V 422 drops the aeroskirts during the second stage burn.Atlas 5 5x1 drops the fairing during first stage burn (in the video I watched).Electron drops its fairing during second stage burn.How about other vehicles?It seems such an advantage to use the vehicle acceleration to get away from the fairing halves.Put those springs between the fairing halves instead of under them. What advantages do people see to the Astra choice?
By Andrew Griggs, Senior Director, Mission Management & Assurance at AstraEarlier this month, we launched for the first time out of Cape Canaveral. While this mission represented historic firsts for Astra, we experienced an anomaly during flight and were unable to deliver the payload to orbit. We deeply regret the loss of the mission and are working to investigate and identify the root cause of the issue. While our current investigation is ongoing, I wanted to share a little more about our process for investigating issues in flight.The Federal Aviation Administration (FAA) authorized Astra to lead the investigation, is providing oversight to ensure any public safety issues are identified and addressed, and will approve the final report. Astra is executing our FAA-approved investigation plan, in addition to industry best practices, which enables us to not only determine and resolve the root cause of a failure, but look across the rest of our systems to see what else might be impacted and make those systems more robust as well. This is a rigorous process that moves rapidly from theory, to experimentation, to action.Our launch investigation process includes four main steps, which are summarized here: 1. Flight Data Review As soon as a flight is complete, even for a fully successful launch, we review flight video and telemetry to compare our expectations with what actually occurred to identify any off-nominal events. 2. Timeline Reconstruction For any off-nominal events, we then reconstruct a timeline of launch-sequence events and telemetry which allows us to understand what happened and when. In this case, our early findings and flight video show that the first stage burn was nominal, and the anomaly occurred during the stage separation process following Main Engine Cutoff. 3. Fault Tree Analyses After we understand the timeline of events, we analyze all of the possible causes of any off-nominal events in order to identify a root cause. We do this by creating fault trees, which are a reliability engineering tool used to organize and analyze the most likely direct causes. We move quickly from theory to experimentation in order to test our hypotheses and narrow in on the root cause. 4. Implementing Corrective and Preventative Actions After we’ve identified and corrected the root cause, we then look across our system to determine how we can apply lessons learned and implement preventive actions for future missions. We view this as the most important step because it helps us continuously improve our system and increase its reliability.It has been a little over a week since our launch. We have already completed steps 1 and 2 in our investigative process, and are currently in the process of finalizing the fault trees (step 3) and implementing corrective actions (step 4).This investigation process is driven by our core value of learning and allows us to test and iterate at speed. We believe that the faster we are able to iterate, the more we can refine our launch system, and the faster we are able to get our customers back to the launch pad. We will share more about what we have uncovered when our investigation with the FAA is complete. Following that, we expect a safe return to launch.
Press release from Astra: Post-Launch Investigation: What We’re DoingQuote from: AstraBy Andrew Griggs, Senior Director, Mission Management & Assurance at AstraEarlier this month, we launched for the first time out of Cape Canaveral. While this mission represented historic firsts for Astra, we experienced an anomaly during flight and were unable to deliver the payload to orbit. We deeply regret the loss of the mission and are working to investigate and identify the root cause of the issue. While our current investigation is ongoing, I wanted to share a little more about our process for investigating issues in flight.The Federal Aviation Administration (FAA) authorized Astra to lead the investigation, is providing oversight to ensure any public safety issues are identified and addressed, and will approve the final report. Astra is executing our FAA-approved investigation plan, in addition to industry best practices, which enables us to not only determine and resolve the root cause of a failure, but look across the rest of our systems to see what else might be impacted and make those systems more robust as well. This is a rigorous process that moves rapidly from theory, to experimentation, to action.Our launch investigation process includes four main steps, which are summarized here: 1. Flight Data Review As soon as a flight is complete, even for a fully successful launch, we review flight video and telemetry to compare our expectations with what actually occurred to identify any off-nominal events. 2. Timeline Reconstruction For any off-nominal events, we then reconstruct a timeline of launch-sequence events and telemetry which allows us to understand what happened and when. In this case, our early findings and flight video show that the first stage burn was nominal, and the anomaly occurred during the stage separation process following Main Engine Cutoff. 3. Fault Tree Analyses After we understand the timeline of events, we analyze all of the possible causes of any off-nominal events in order to identify a root cause. We do this by creating fault trees, which are a reliability engineering tool used to organize and analyze the most likely direct causes. We move quickly from theory to experimentation in order to test our hypotheses and narrow in on the root cause. 4. Implementing Corrective and Preventative Actions After we’ve identified and corrected the root cause, we then look across our system to determine how we can apply lessons learned and implement preventive actions for future missions. We view this as the most important step because it helps us continuously improve our system and increase its reliability.It has been a little over a week since our launch. We have already completed steps 1 and 2 in our investigative process, and are currently in the process of finalizing the fault trees (step 3) and implementing corrective actions (step 4).This investigation process is driven by our core value of learning and allows us to test and iterate at speed. We believe that the faster we are able to iterate, the more we can refine our launch system, and the faster we are able to get our customers back to the launch pad. We will share more about what we have uncovered when our investigation with the FAA is complete. Following that, we expect a safe return to launch.
Quote from: Ken the Bin on 02/22/2022 01:59 pmPress release from Astra: Post-Launch Investigation: What We’re DoingQuote from: AstraBy Andrew Griggs, Senior Director, Mission Management & Assurance at AstraEarlier this month, we launched for the first time out of Cape Canaveral. While this mission represented historic firsts for Astra, we experienced an anomaly during flight and were unable to deliver the payload to orbit. We deeply regret the loss of the mission and are working to investigate and identify the root cause of the issue. While our current investigation is ongoing, I wanted to share a little more about our process for investigating issues in flight.The Federal Aviation Administration (FAA) authorized Astra to lead the investigation, is providing oversight to ensure any public safety issues are identified and addressed, and will approve the final report. Astra is executing our FAA-approved investigation plan, in addition to industry best practices, which enables us to not only determine and resolve the root cause of a failure, but look across the rest of our systems to see what else might be impacted and make those systems more robust as well. This is a rigorous process that moves rapidly from theory, to experimentation, to action.Our launch investigation process includes four main steps, which are summarized here: 1. Flight Data Review As soon as a flight is complete, even for a fully successful launch, we review flight video and telemetry to compare our expectations with what actually occurred to identify any off-nominal events. 2. Timeline Reconstruction For any off-nominal events, we then reconstruct a timeline of launch-sequence events and telemetry which allows us to understand what happened and when. In this case, our early findings and flight video show that the first stage burn was nominal, and the anomaly occurred during the stage separation process following Main Engine Cutoff. 3. Fault Tree Analyses After we understand the timeline of events, we analyze all of the possible causes of any off-nominal events in order to identify a root cause. We do this by creating fault trees, which are a reliability engineering tool used to organize and analyze the most likely direct causes. We move quickly from theory to experimentation in order to test our hypotheses and narrow in on the root cause. 4. Implementing Corrective and Preventative Actions After we’ve identified and corrected the root cause, we then look across our system to determine how we can apply lessons learned and implement preventive actions for future missions. We view this as the most important step because it helps us continuously improve our system and increase its reliability.It has been a little over a week since our launch. We have already completed steps 1 and 2 in our investigative process, and are currently in the process of finalizing the fault trees (step 3) and implementing corrective actions (step 4).This investigation process is driven by our core value of learning and allows us to test and iterate at speed. We believe that the faster we are able to iterate, the more we can refine our launch system, and the faster we are able to get our customers back to the launch pad. We will share more about what we have uncovered when our investigation with the FAA is complete. Following that, we expect a safe return to launch.This is the real issue with Astra's "low reliability" pitch - it's a highly regulated industry that can tie you in knots over a launch that, because of the price point and cost of the launch site, cannot break even. And then you sit still for 3-6 months while the FAA checks your working. And if it keep being unreliable, why would they keep giving you a license?
Because FAA is not supposed to care about reliability, only about safety.If they can demonstrate that they are safe even when failing the FAA shouldn't care one way or another.
Quote from: mn on 02/22/2022 09:29 pmBecause FAA is not supposed to care about reliability, only about safety.If they can demonstrate that they are safe even when failing the FAA shouldn't care one way or another.Sure, but if you can confidently say "we're sure that the ways in which our vehicle fails will always happen within approved launch corridors, with no harm to people or property on the ground," you know enough about your vehicle to design it to not fail in the first place.
By Andrew Griggs, Senior Director, Mission Management & Assurance at AstraNote: Astra has not yet finalized the LV0008 investigation results with the FAA. The information in this blog post is preliminary until the investigation has been fully closed.On February 10, 2022, we launched Launch Vehicle 0008 (LV0008). This was our first launch with a deployable customer payload and our first time launching from Cape Canaveral. After a nominal first stage flight, an anomaly occurred during the stage separation process which resulted in the upper stage not reaching orbit and the end of the mission. We immediately initiated our investigation process to determine the root cause of the anomaly. Now, we can share more about what we’ve learned to date.What Happened:Our investigation verified that the payload fairing did not fully deploy prior to upper stage ignition due to an electrical issue. The separation mechanisms (our fairing has 5 of these) were fired in an incorrect order, which resulted in off-nominal movement of the fairing that caused an electrical disconnection. Due to the disconnection, the last separation mechanism never received its command to open, which prevented the fairing from separating completely before upper stage ignition.Separately, we discovered a software issue that resulted in the upper stage engine being unable to use its Thrust Vector Control system. This led to the vehicle tumbling after the off-nominal stage separation, and caused the end of the mission.What We Learned:The root cause of the fairing separation issue was an error in an electrical harness engineering drawing. This harness was built and installed onto the vehicle exactly as specified by our procedures and the engineering drawing, but the drawing error led to two harness channels (pictured below at the locations ‘4’ and ‘5’) being swapped. Prior to the LV0008 flight, we had conducted an end-of-line signal test to verify the separation system and ensure that the system was wired correctly. This test would have been able to detect an error in the harness build or installation, but it was unable to detect an error in the design. The swapped separation channels caused a different deployment sequence than we expected, and this led to the failure to open the fairing. We’ve been able to recreate the failure mode by conducting several experiments at our factory with real flight hardware, one of the benefits of having an active production floor with several launch vehicles in various states of production at the same time.After determining the root cause of the software issue, we found that our flight control software was vulnerable to a specific “packet loss” failure mode. A missed series of signals resulted in a chain of events, resulting in the upper stage’s inability to recover from its tumble. Although we had designed our software suite to be resilient to packet loss, an unlikely combination of factors caused a failure that we didn’t predict. We have been able to use our hardware-in-the-loop simulator to step through exactly what happened and diagnose the root cause with high confidence.How We Fixed It:Through the investigation process we had identified two problems that needed fixing: the harness issue and the software issue. Soon after discovering the harness drawing error, we fixed the drawing and incorporated the change on previously built harnesses. We also implemented a new end-of-line signal test that will allow us to identify this class of issue in the future, if it were to occur, prior to launch. On the software side, we’ve introduced a trio of upgrades designed to make our system even more resilient to packet loss and other similar failure modes. Through constant iteration and extensive testing, we have been able to demonstrate that the changes eliminate the failure mode we saw on LV0008, while making the software suite much more robust.Here at Astra, iteration and learning are core parts of our culture. I’ve been continuously impressed with the speed, passion, and diligence that the team showed as they worked through these complex issues to identify exactly what occurred and determine the right path forward to resolve each problem. With the root causes identified and corrective measures in place, we’re preparing to return to the launch pad with LV0009 soon — stay tuned!
Astra has announced the results of the ELaNa 41 mission failure investigation. Two separate failures - an electrical issue with the fairing, and a software issue on the upper stage - caused the loss of mission.https://twitter.com/TGMetsFan98/status/1500834111073792004
Without the wiring fault it may have been longer into flights for them to find the software issue, so all things considered it worked out well for them.
When asked if the upper stage TVC anomaly was a knock-on effect from the fairing anomaly, Astra stated that “We have determined that these issues are independent and are ensuring the mitigations fully address the root causes for each issue.”
Quote from: cpushack on 03/07/2022 05:56 pmWithout the wiring fault it may have been longer into flights for them to find the software issue, so all things considered it worked out well for them. The article seems to imply they were entirely independent.QuoteWhen asked if the upper stage TVC anomaly was a knock-on effect from the fairing anomaly, Astra stated that “We have determined that these issues are independent and are ensuring the mitigations fully address the root causes for each issue.”
If the failure is caused by incorrect engineering diagram, why didn't it cause problems in previous launches?
Quote from: su27k on 03/08/2022 02:36 amIf the failure is caused by incorrect engineering diagram, why didn't it cause problems in previous launches?I kind of assume the diagram was ambiguous, so previously it was assembled correctly, either by accident, or the person doing the assembly knew the correct way to do it even though the diagram was unclear.
Quote from: Redclaws on 03/07/2022 06:28 pmQuote from: cpushack on 03/07/2022 05:56 pmWithout the wiring fault it may have been longer into flights for them to find the software issue, so all things considered it worked out well for them. The article seems to imply they were entirely independent.QuoteWhen asked if the upper stage TVC anomaly was a knock-on effect from the fairing anomaly, Astra stated that “We have determined that these issues are independent and are ensuring the mitigations fully address the root causes for each issue.”While the 2 issues are independent, i guess the second one only affects resilience for edge cases, in this case induced by the upper stage blowing through the partially opened fairing. So 2 separate issues, but one event triggered by the other, so not completely independent.