3 ms·
Keep in mind that this is _reaction time_. As in, if something happens to an engine how fast do I need to react to safe it before it spreads to other things. Tu
by elteto 5y ago
Keep in mind that this is _reaction time_. As in, if something happens to an engine how fast do I need to react to safe it before it spreads to other things. Turns out that 20ms response time is plenty appropriate.
Are there any processes in combustion dynamics faster than 20ms? You bet there are, and when the engine is being tested they are instrumented with high speed probes, because during development/testing you want to _understand_ what’s going. When you are flying you want to stay in control first and foremost.
Of course, it would be awesome to have everything on high speed data acquisition channels. But there is a very limited telemetry budget and everyone is fighting for it. So compromises have to be made.
There probably are high speed probes on the rocket, such as strain gages. And if an engineer thinks that having a high speed engine metric would be _critical_ to do postmortems then it will most likely be included.
So, I would say that assigning telemetry budgets it’s a holistic process where multiple teams fight/cooperate to share that budget and prioritize absolutely critical data channels.
- jakeinspace 5y agoRocket engines have built-in computers, like ECUs in cars, that likely operate at a much finer update cycle than 50hz. Flight computers are not concerned with every aspect of timing when it comes to the engines, they just need to tell the engine's controller when to fire.