Eyeballing the chart here it looks like computers in 1995 were about 2-3 OOMs worse than computers in 2015. Payload capacity of Falcon 9 is measured in 1000s of kg. So you could cut off some of that payload capacity and have a 5000 kg computer in 1995. Would that be able to do the work of whatever computer they used in 2015? Well, how many kg did those computers weigh? More than 5kg? This thread has some info but no numbers.
idk, seems probable to me that computers weren’t the limiting factor.
It took quite a few attempts to get the Falcon 9 to land correctly. A lot of the work to get it to land correctly like involved getting the computer models right. Everything that’s involved in computer modeling got better over the 20 years.
Hardware in the rocket got cheaper. Compute for the offline models got cheaper. On the physics side, we likely learned lessons about how to model the airflow and other factors better.
Dragon runs a special version of Linux that’s optimized for low latency. It’s unclear to me whether a low-latency OS that would do the job was around in 1995.
I don’t know anything about the requirements for the Falcon or Dragon computer systems, but I do know that in 1995, real-time operating systems had existed for many years. At that time, computers that I would guess (maybe wrongly) would be adequate for the task weighed in at 10s of kilograms. Of course, the ones I worked with weren’t built to endure the rigors of space flight. Still, I would guess that the 1995 level of computer technology would not have been a show-stopper for such rockets being built, though the computing requirement would have added more to the cost than today.
But I wonder whether advances in materials science since 1995 might be crucial?
It’s a ballpark number, anything from 100kg+ would have made a 90s equivalent too heavy. The difference compared to consumer computers is expected once you realize it includes multiple interlinked triply redundancy systems and the wiring, mounting structure, power supply system, shielding, etc. for all that.
How large (in kg, or in FLOPS) are the computers on the Falcon 9 today?
In kg terms, less than 0.1% of the total launch mass of the Full thrust variant (549 t).
Eyeballing the chart here it looks like computers in 1995 were about 2-3 OOMs worse than computers in 2015. Payload capacity of Falcon 9 is measured in 1000s of kg. So you could cut off some of that payload capacity and have a 5000 kg computer in 1995. Would that be able to do the work of whatever computer they used in 2015? Well, how many kg did those computers weigh? More than 5kg? This thread has some info but no numbers.
idk, seems probable to me that computers weren’t the limiting factor.
It took quite a few attempts to get the Falcon 9 to land correctly. A lot of the work to get it to land correctly like involved getting the computer models right. Everything that’s involved in computer modeling got better over the 20 years.
Hardware in the rocket got cheaper. Compute for the offline models got cheaper. On the physics side, we likely learned lessons about how to model the airflow and other factors better.
Dragon runs a special version of Linux that’s optimized for low latency. It’s unclear to me whether a low-latency OS that would do the job was around in 1995.
I don’t know anything about the requirements for the Falcon or Dragon computer systems, but I do know that in 1995, real-time operating systems had existed for many years. At that time, computers that I would guess (maybe wrongly) would be adequate for the task weighed in at 10s of kilograms. Of course, the ones I worked with weren’t built to endure the rigors of space flight. Still, I would guess that the 1995 level of computer technology would not have been a show-stopper for such rockets being built, though the computing requirement would have added more to the cost than today.
But I wonder whether advances in materials science since 1995 might be crucial?
Are the necessary algorithms parallelizable under the strict latency requirements?
2 OOMs would translate into a 50 000 kg computer system in 1995 v. a 500 kg computer system in 2015, not 5000 kg.
The computer on a 2015 Falcon 9 weighed 500kg? Really?
It’s a ballpark number, anything from 100kg+ would have made a 90s equivalent too heavy. The difference compared to consumer computers is expected once you realize it includes multiple interlinked triply redundancy systems and the wiring, mounting structure, power supply system, shielding, etc. for all that.
A100′s weigh less than 4kg. Three of them would be 12kg. I find it hard to believe that Falcon 9′s use 100kg worth of computer.