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Civilian Space Launch Imminent
rossjudson writes: "Looks like the Civilian Space Exploration Team has gotten clearance from the FAA and the Bureau of Land Management to attempt the first amateur flight into space. That's pretty cool. Maybe one of you space-mathematics types out there can educate us on just what 0-Mach 5 in 15 seconds really means! Is this thing gonna just blow up?"
subject says it all... speed of sound = 1100 f/s, so 5500 f/s in 15 s = 1100 f/s in 3 s = 367 f/s^2. 10 Gs would be 322 f/s^s. Close enuf. Increased accuracy is welcome.
You could've hired me.
Wasn't there a prize for the first team to loft 1 kg to 100 km? Would this qualify?
(no, it wasn't X-prize, that was for bringing people into space and re-launching in, what, a week?)
Been a while.
I'm disappointed, though, that they're being asked to keep the exact launch date a secret. If they can't protect a rocket in the middle of the Nevada desert from terrorists (or tourists), then we're all screwed.
0 to Mach 5 in 15 seconds?
That's going from 0 mph to 3700 mph, or 0 to 5400 ft/s in a quarter of a minute; assuming 740 mph = Mach 1.
a = [v(2) - v(1)]/delta t
a = (5400 ft/s - 0 ft/s)/15 s = 360 ft/s^2
or about 11gees.
9 gees is a heavy gee load in air combat maneuvering (dogfighting), so 11 gees is a very heavy gee load. At least over a protracted period.
"Oh drat these computers, they're so naughty and so complex, I could pinch them." --Marvin the Martian
I wonder what their insurance is like? They have the rocket landing somewhere near Quebec City. I don't think Quebec knows or ready. This could be more interesting then I thought.
Maybe one of you space-mathematics types out there can educate us on just what 0-Mach 5 in 15 seconds really means!
It means, in layman's terms, "chunky salsa."
Moderate drunk! It's more fun that way!
Now, the speed of sound at sea level is around 340m/s, which gives us around 11.7g's of acceleration, and an altitude of 42,000 feet in 15 seconds.
However, the speed of sound at that altitude is significantly slower, around 290m/s-300m/s (according to my information), so our numbers for the acceleration should be a bit HIGH.
Of course, without a nice function for me to integrate against, it is a little trickier to figure out what the acceleration really is, but we can put some bounds on it. As determined, the upper limit is 11.7g's of acceleration. The lower limit will be around 10g's. (This is found by using the slowest speed of sound number that we could possibly run across).
So, with that range in mind, we can see that a reasonable estimate for the acceleration would be about 11g's +/- 1g.
There, I feel more rigorous. I feel better now. :) (This is what I get for being a physicist.)
-Jeff
Here is a pretty cool article on the future possbility of a space elevator
A fighter pilot sits fairly upright. It's a long way from the top of the head to the bottom of the feat, compared to laying down, where your head and feet are at the same level. Of course, at 11G, the blood pressure in the blood vessels at the back of your head while laying down perfectly would be about like hanging from your feet at 2G. Nevertheless, it's endurable, and greatly increases efficiency of the propulsion. You wouldn't want to perform complex tasks at even 3G, but you could easily endure it.
The stress decreases with size of the subject anyway, so don't feel sorry for the guinea pig - envy him.
We're still living with the 8088. Intel just bolted on all sorts of bloat to it.
How are you measuring cost effectiveness.
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Ignore this bit. I'm just padding the time to 20s.
-- SIGFPE
about 10 Gs?
I think the big source of error in our calculations here will be our uncertanty of the acceleration profile. While constant acceleration is certainly a reasonable solution, it isn't the only possibility. For example, we could have:
I sure hope this isn't what happens, but it could fit the numbers as well as "constant accelleration at 10.5G +/- a fudge."
-- MarkusQ
Actually, the speed of sound is almost completely independent of pressure.
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Well, certainly they could spend more money and time to do something flashier than a quick up-and-down. But the purpose of this mission is to make history, to have the first civilian space flight, and that's no mean feat. It's not just so that they can say they did it -- that's a means to an end. It's to open up the door, make people realize it can be done, get other people working on the big, flashy projects. Since the purpose is to get the ball rolling, I think they chose right by doing it quick and simple rather than delaying to add more features to the mission.
My deviantArt site
Don't people do this all the time with Sounding rockets? Although maybe the point is that NASA runs that program too, and this is really independent? Still, it doesn't seem that big a deal...
Energy: time to change the picture.
Hi, everyone. I'm glad to join your discussion here.
I'm one of the leaders of the Civilian Space eXploration Team (CSXT). I head up all of the avionics development of the rocket project you are discussing: http://www.civilianspace.com My specialty is electronics & communications. If I can answer any questions for you, let me know.
BTW: I see a message thread speculating on the number of g's. We expect a peak of 18 g's just before motor burnout.
Some other numbers you might find interesting:
* Motor burnout at 14.2 seconds
* Mach 5.2 at motor burnout
* Maximum dynamic pressure (Max Q): 8,500 pounds per square foot (occuring at 13.6 seconds)
F.Y.I., Since our launch is less than a month away, I'm pretty consumed with pre-launch activities. I may only be able to stop by this forum a couple times per week. I apologize in advance for any tardy replies.
-- Eric