[jacquesm]

What an impressive project.

> Next up was maneuvering from our LEO drop-off altitude down to VLEO, where it would be safe to eject the telescope contamination cover

Why would it be unsafe to do this earlier?

> We had been tracking intermittent memory issues in our TT&C radio throughout the mission, working around them as they appeared. Our best theory is that one of these issues escalated in a way that corrupted onboard memory and is preventing reboots. We've tried several recovery approaches. So far, none have worked, and the likelihood of recovery looks low at this point.

Seems to be a pretty big problem as well, I wonder what their ideas are to diagnose the root cause here.

It all sounds a bit overoptimistic, but that may just be my interpretation.

[Alasater]

Space safety for sure on the cover, although I'm not sure we'll have that cover for future launches because it was less than easy to coordinate with the FCC on where to eject it.

The radio came from a supplier who has been investigating the issue. We had concerns with their NAND and ECC implementation, and we weren’t able to fully root-cause it with them. Going forward, we’ll be building our own radios, which will make it easier to test, iterate, and resolve issues like this internally, or at least be able to trace possible latch ups or destructive failures and implement the right levels of redundancy.

[jacquesm]

Ok, good luck with that, that's a tough environment for such sensitive stuff. Unfortunately your application seems to be so advanced that you can't get away from having high speed and super integrated stuff on board there otherwise you'd be more intrinsically safe against such issues. The fact that it worked well initially and then degraded until it failed is a strong indicator of the kind of process that caused the failure but unfortunately that still leaves a whole slew of options on the table.

Much good luck with this, those are hard problems to solve but you guys got so much right on the first try that you're probably ahead on your schedule now so you may have the time and the budget to get this right. I've visited the ESA open day a while ago and have seen the guts of what goes into satellite manufacture (not the most recent stuff, just what they had on display) and what struck me is that the degree of rigor that goes into designing stuff that is in the most literal sense out of reach for fixes or diagnostics requires simulating the environment the device will operate in to the best of their ability. This results in autoclaves that you can walk around in and various radiation sources to be able to test how the devices respond to space conditions.

Your manufacturer/supplier will probably come away from this effort with as much knowledge and improvement items as you do. Given the short time to failure I'm not so sure redundancy alone would have been a sufficient fix, but that's obviously bystander perspective, you know far more than I do. But it certainly is an amazing and interesting project.

[MobiusHorizons]

I think they want to get low enough that the jettisoned cover will not stay in orbit long or run into anything.

[jacquesm]

Ah, safe for others, not for the telescope. Thanks, I did not consider that option.

[topherhaddad]

Yes, exactly. Space safety :)