Recent content by RGregoryClark

Thanks. There were a couple scenarios I'm interested in. They have to do with using an upper stage on a different rocket. I want to know how the stress on the stage would be changed. One example is the proposed Liberty rocket that used an Ariane 5 core stage as an upper stage on top of a SRB...

Thanks for that. It seems the only thing preventing a solar thermal propulsion stage is the lack of lightweight mirrors or lenses for square kilometer scale collectors. This would seem to be an easier task than getting light weight fission reactors or plasma drives so NASA should be...

A related question: how do you calculate the force on an upper stage when a lower stage is firing? You would think the entire force of the thrust is communicated up through the rocket so that the same force operates on the upper stages. But this would lead to the conclusion that for a rocket...

The formulas for buckling under axial force only involve the applied force or pressure, such as with Euler buckling. But if you look at the case of a rocket as the fuel is burned off, the force, i.e., the thrust, stays the same but the acceleration increases as the mass decreases. But we are...

Assuming comet C/2013 A1 misses Mars by 37,000 km how much delta-v would you need to nudge it to hit Mars? This might not be purely of academic interest. Already we've seen two Earth encounters whose likelihood together was one in hundreds of millions. This comet to make a close encounter...

That's the kind of scenario I'm considering. Also, the altitude considered to be "space" is only 60 miles. Bob Clark

At those prior orbit(s) it doesn't have to be that close. Within say a few tens of miles so that on that final close approach its orbit looks very different than the original orbit. Bob Clark

I like that description. Bob Clark

Astronomers have calculated that the Russian meteor and asteroid 2012 DA14 have very different orbits: Astronomers Calculate Orbit of Chelyabinsk Meteorite. Still because of the very unlikely probability of their occurring together purely by chance, I would like to see some simulations of...

Your mentioning of Asimov brought to mind one of his short stories called "No connection!" I can't remember what events the non-human (though of Earth!) scientists forced themselves to believe were just a coincidence, but the story is available here: No Connection...

That is a great example. Another great example in the news now is the Russian meteor and asteroid 2012 DA14 closest approach occurring on the same day. Bob Clark