Predictably, someone is freaking out on twitter over tardigrades:https://twitter.com/AstroTraviesa/status/1160318429322199046BTW, didn't China send silkworms to the Moon, where is "planetary protection" folks when China was doing it?
impacted the moon at something like 1 km/s
Quote from: whitelancer64 on 08/13/2019 03:39 pmimpacted the moon at something like 1 km/sEstimated impact velocity was 500 km/hour (from https://spacenews.com/spaceil-says-chain-of-events-led-to-crash-of-lunar-lander/ ) which is 0.14 km/sec. Unless there was a much faster estimate I missed.
Interesting take by Robert Zubrin:https://www.nationalreview.com/2019/08/planetary-protection-rules-hamper-space-exploration/
Looks like the root cause of the crash landing are "unknown unknowns"! Without more information, only SpaceIL and Firefly will be learning this lesson."In some cases, despite the use of high-TRL components, the unknown unknowns caused problems, and IAI has made the appropriate upgrades to mitigate these problems for future missions."https://firefly.com/genesis/
Quote from: Steven Pietrobon on 09/14/2019 05:15 amLooks like the root cause of the crash landing are "unknown unknowns"! Without more information, only SpaceIL and Firefly will be learning this lesson."In some cases, despite the use of high-TRL components, the unknown unknowns caused problems, and IAI has made the appropriate upgrades to mitigate these problems for future missions."https://firefly.com/genesis/This is so funny!Meaningless PR BS
In that paper [presented at the IAC in October], [IAI] said one of two inertial measurement units (IMUs) on the spacecraft malfunctioned during descent and was shut down by the onboard computer. Controllers uploaded commands to turn the unit back on.“This led to a cascade of resets in the spacecraft avionics, which shut off the main engine and prevented proper engine activation,” the paper stated.A review of the lander telemetry found that the decision to turn the IMU back on “triggered a communication block” between the IMU and the central processing unit, according to the paper, keeping data from the other, working IMU from reaching the system and thus causing the thrusters to turn off and the computer to reboot.“As result, all accumulated [software] updates that were stored on a volatile memory (SRAM) were eliminated during reboot,” the paper stated. “Therefore, the computer did not contain all the essential changes implemented during the flight, which made autonomous recovery impossible.”
I wonder why did they try to turn the IMU back on if it's malfunctioning.
Among the changes recommended in the paper were to allow full updates of the lander’s software during flight, and storing that software in non-volatile memory that is not wiped during a computer reboot.
"In some cases, despite the use of high-TRL components, the unknown unknowns caused problems, and IAI has made the appropriate upgrades to mitigate these problems for future missions."https://firefly.com/genesis/
Quote from: flyright on 04/18/2019 02:32 amIt's interesting that the IMU issue was called out a couple minutes before the engine not running was called out. I'm wondering if the "chain reaction" mentioned in the preliminary findings involved loss of attitude information that then might have prompted the engine shutdown.I'm thinking it would be good for the next attempt if there is no actual hardware issue involved in this failure. Sounds like it might just be software.My understanding is that the spacecraft was using IMU 1 and was not initially affected by the failure of IMU 2. One engineer asks if they should attempt to enable IMU 2 and another engineer asks 'would that cause the system to switch to it (presumably 'it' means IMU 2). Perhaps despite the word of caution from the 2nd engineer someone did send a command to attempt to restart IMU 2 and perhaps that is what they mean by a bad command starting a chain of events...Lots of speculation here, please take it all with a large serving of salt.
It's interesting that the IMU issue was called out a couple minutes before the engine not running was called out. I'm wondering if the "chain reaction" mentioned in the preliminary findings involved loss of attitude information that then might have prompted the engine shutdown.I'm thinking it would be good for the next attempt if there is no actual hardware issue involved in this failure. Sounds like it might just be software.
