The galactic year, also known as a cosmic year, is the duration of time required for the Solar System to orbit once around the center of the Milky Way Galaxy.[1] Estimates of the length of one orbit range from 225 to 250 million "terrestrial" years.[2] According to NASA, the Solar System is traveling at an average speed of 828,000 km/h (230 km/s) or 514,000 mph (143 mi/s),[3] which is about one 1300th of the speed of light.
a Question?is the recovery time from a prolonged stay in zero-g affected by recovering in a reduced gravitational environment, say one-third-g?
When something has a specific impulse (Isp) of 5000 s, what does that mean? What lasts for 5000 s?
lbf and lb are not the same thing, and yes, we know you're not civilized
I knew it had something to do with fuel, but I was trained in metric and I knew we wouldn't be measuring thrust in kilograms.
Quote from: scienceguy on 05/15/2013 05:14 pmI knew it had something to do with fuel, but I was trained in metric and I knew we wouldn't be measuring thrust in kilograms.Didn't the Russians use kilogram-force for a long time for their engine specs?
Quote from: ugordan on 05/15/2013 07:58 pmQuote from: scienceguy on 05/15/2013 05:14 pmI knew it had something to do with fuel, but I was trained in metric and I knew we wouldn't be measuring thrust in kilograms.Didn't the Russians use kilogram-force for a long time for their engine specs?Yes. The Soviets used metric, but not SI. They still used seconds for Isp, and pressures were something weird too (kgf/cm^2 maybe).
To nit-pick, the SI unit of pressure is the pascal, not the Pascal. The SI symbols for units derived from people's names are capitalized, but not the units themselves.
But plumbers think in terms of the force units of mass.
Quote from: Proponent on 05/17/2013 11:51 amTo nit-pick, the SI unit of pressure is the pascal, not the Pascal. The SI symbols for units derived from people's names are capitalized, but not the units themselves.Yeah, another of those "logic" that come out of an international committee. The full name is not capitalized, to "avoid" confusion the the actual person (when the whole purpose of naming it after someone is to immortalize its name), but it's degrees Celsius (the "d" is not capitalized!). And, to add insult to injury, the symbol is capitalized (Pa). I love metric, but once you allow a bunch of bureaucrats to make decisions nothing practical can come out of it.That's why the Russians use the metric units the way you actually work with them. When you want pressure and use US customary, you want the force to be in lbf. Same for metric, you usually need it in kgf. So, don't let the SI bureaucrats get in the way of using the most practical units for actual work.Again, it does makes sense to use Pa for things like Martian atmosphere, and N for the thrust of an orbital vehicle. But plumbers think in terms of the force units of mass.