twibbles
-
Content
269 -
Joined
-
Last visited
-
Feedback
0%
Everything posted by twibbles
-
Or something ablative, absorbing heat by vaporising Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Yeah, that's why most rockets are launched east-wards, so they don't have to go against Earth's rotation. I suppose i could do a spredsheet, with atmosphere density against height. With the velocities from gravational acceleration at different heights, i could work out the drag at different altitudes, and get a graph out of it, but it sounds like proper work That is assuming a straight line fall in relation to the Earth's and the atmosphere's rotation of course. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Amen to that! Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Ahh.. I see your point. I knew i was missing something
-
You also have to take into consideration there is no drag in space. So unless you've some type of mechanical device (rocket or some uber fan) you'll have no way of slowing down before you slam into the earths upper atmosphere. Kind of like a bug on a windshield, cept this car is traveling at 4000mph. But then atmosphere density increases exponetionally towards the ground. And drag is function of density and the squared of velocity, drag would gradually increase the lower you go. The big question is wether the peak deeceleration is survivable. Eugene edited to change "drag is a function of velocity and the squared of velocity" "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
No one slows orbital velocity down to zero because it's very expensive to do and technically very challanging. Everyone's seen the shuttle launching. Other then energy lost through drag in the atmosphere, the the boosters and main engines are used to bring it to orbital velocity. Now imagine needing the same rockets and engines to slow it back down to zero. And the only you need the corect angle for re-entry in the first place is because of the orbital velocity of the object. If you shoot BB at an oblique angle to a pool of water, it'll bounce off. If you drop it straight down, there's no problem. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
color me ignorant, but how does one achieve "zero orbital velocity?" A very big rocket firing against the direction of travel in orbit, or starting on the ground and going straight up in a rocket could do it. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
The shuttle needed to lose it's orbital velocity, which was 27,400 Km/h if i remember right, hence needing heat shields to absorb the heat generated by the friction against the atmosphere while aerobraking. If orbital velocity is taken out of the question like shaiziel was saying, it's another question all together Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Hmm, assuming zero orbital velocity... I don't see any reason why it's shouldn't be survivable.. The only reason the space shuttle needs heat shields is because it needs the atmosphere to slow it down, unless i'm missing somethiing here. If Joe Kitinger survived his jump... Thinking out loud again: You won't be going faster then terminal velocity.As the atmosphere thickens the lower you go, your terminal velocity lowers. Got to go think about it some more. Edited to add: In vacuum, acceleration is constant, velocity increase is constant. Air density decreases exponentionally with height, and terminal velocity depends on air density. I suppose i could work it out, but i just finished an exam on fundimental aeronautics and i don't want to do anything similar for the next three months. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Just thinking out loud here... If i remember right, Orbital velocity of a geosync orbit is 11,000 Km/h, Low earth orbit is 27,400 Km/h. To get back to the surface, you need to lose that. So i guess the question is wether you can lose the speed slow enough to survive re-entry. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Been tried before, didn't work out for Nazi Germany. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Might be a bit off topic here, but wasn't Nagasaki the secondary site, with Kokura being the primary? And... Brillant!! Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Distilled water would be best i guess, don't want and residue that's left after the water evaporates to short out anything. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
What makes risks acceptable versus unacceptable?
twibbles replied to lawrocket's topic in General Skydiving Discussions
My biggest fear is taking myself out since I should know better. My biggest fear is screwing up and taking someone else out. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move." -
Shannon's story on Fox News tomorrow morning (6/1)
twibbles replied to JankyBob's topic in The Bonfire
Thanks for putting it up, really appreciate it. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move." -
Well said. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Not if i have anything to say about it..
-
I'm up for it. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Tell me about it, at my parent's house, the one in malaysia, we got three mango trees in the garden. Lots of fun when it's fruiting. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Another thing i'm worried about is the talks of putting conventional warheads in sub launched ballistic missiles. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
Tell me about it. My dad's a senior consultant at a hospital, my mom's a surgeon. My sister and my brother's doing medicine right now. I told them i want to be an engineer, and never got a straight answer out of them when we were discussing my options. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
I'm done with all my exams and presentations for my degree this acedemic year, it's not raining, and i'll be seeing a very good friend this weekend :) Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
My biggest regret is that i've never had the opportunity to meet her in real life.. Bonfire would never be the same again. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."
-
I cant believe this needs to be said but.......
twibbles replied to dgskydive's topic in The Bonfire
One thing for sure, i'll be changing the way I talk to friends who are thinking of skydiving. As much as i want people to get into the sport, i don't want them to have anything less the the best advice i can give. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move." -
The list is always too long, from the first name onwards. But the rewards of knowing someone new ALWAYS outweighs the risk of losing someone. It hurts, but i rather know someone new then not at all. Just my two cents. Eugene "In the beginning the Universe was created. This has made a lot of people very angry and been widely regarded as a bad move."