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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.
I do believe that Mach-1 is the speed of sound, therefore Mach-2 would be twice the speed of sound, Mach-3 is 3x the speed of sound, etc...so what they're saying is they're ship can go from 0-to-5x the speed of sound in 15 seconds.
I want to go too! I want to be the first pot head geek in space. At least publicly :)
Everyone is entitled to their own opinion. It's just that yours is stupid.
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.
In terms of car acceleration... 0 - 60 mph in 0.25 sec
demon
-----
Nothing is ever a total loss; it can always serve as a bad example.
At 21C (70F) altitude 0, speed of sound = 344 m/s = 1129 ft/s
1G = 9.81m/s^2 (at the equator)
So, the acceleration = 344 * 5 / 15 = 114.6 m/s^2 = 11.69 G.
Wow, that's a lot. Jet fighter pilots usually blackout around 9G. I suppose the way the guinea pig is seated can make things better.
Banging your head with a hammer is good for you. It just fells so good when you stop.
SNS Not Sig
Slashdot Uncertainty Principle: The product of the relative error in a Slashdot post with a mathematical result, and the likelihood of it being first is a constant.
You could've hired me.
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
so can they utilize that anti-grav device (assuming it worked and they were able to apply enough power) to cancel out those Gs caused by this acceleration?
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.
Incidentally, as a side question - anyone know if Mach 1 refers to the speed of sound in air at sea-level/standard temperature, or is it a variable depending only upon the speed of sound in whatever situation you're referring to?
-T
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.
Any bets on how long before NASA goes the way of the 8088 microchip?
--CypherDragon
that thinks that this is more costly than its really worth? To me -- it looks like this is going to be an up and down job..... okay..... Cool, but there is alot of money involved. Wouldnt it be much more cost effective to do at least an orbit, and come down?
Dont get me worng, alot more homework is involved, but still....
Sigs are nice guns
Don't you mean "feels"?
Taken from NASA's Site "It takes only about eight minutes for the Space Shuttle to accelerate to a speed of more than 17,000 miles (27,358 kilometers) per hour." I'm not sure of the exact speed of sound, but it's something like 650 MPH, so that would mean the Shuttle goes from 0-Mach 26.15 (Using 650 MPH, it can vary depending on air temp, but not by much) in 8 minutes.
Request: ECM unit, 1000 km fullerene cable, 1 tactical nuclear weapon. Reason: Birthday party for foreign dignitary.
If you assume a constant accleration, which is not the case (this is because the atmosphere is more dense at low altitudes, and means that the drag is much higher on the rocket towards the begining of it's flight), then you can calculate the acceleration.
You really need to take into account the fact that the speed of sound decreases with altitude. Using data from the U.S. standard atmosphere of 1976, in a non-linear shooting method and an initial guess of 98m/s/s...
99m/s/s or 10.1G reaching mach 5.0 at an altitude of 11138 meters
(the shooting method turned out to be linear because the speed of sound is constant to 4 significant figures between 11000 andd 20000 meters)
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
While this doesn't sound all too impressive, I'm glad to hear of it. More needs to come of space flight, and NASA surely isn't doing much on its own.
[offtopic] Frankly, I almost with that NASA was a corporation... [/offtopic]
The Political Programmer
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
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.
Basic physics, assuming constant acceleration (approximately correct for a rocket): v(t) = v(0) + aT
We know v(0) = 0 m/s, v(t) = Mach 5 = 1700 m/s, and T = 15 seconds. So let's find the acceleration. A little Algebra shows us:
a = ( v(t) - v(0) ) / T
a = ( 1700 m/s ) / 15 s = 113 m/s^2
Which is about 12Gs, twelve times the force of gravity on earth. Much more than the several G's of the Space Shuttle. More than a human can stand for more than a few seconds before passing out.
Resources:
How are you gentlemen?
After reading this article , I think anyone and everyone should support the Civilian Space Exploration Team.
Theyre taking off from Nevad and end up in QUebec in 10mins....Im impressed!
>The nominal landing point is approximately 26 >miles downrange...with a total flight time of >about 10 minutes.
I presume your whole post is based on that graphic on their page.
z
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
since you're thanking him, i think that means you are being sarcastic. should i also suppose you are reading all of this on a computer?
I hereby, and until notice to the contrary, endow the Bowery Award for Amateur Rocketry with $1000 going to the next amateurs launching a vehicle to a height in excess of 200 kilometers, to be disbursed at my sole discretion.
The Stark Draper Open Source Rocketry Award (3 oz of gold for reaching 200km.)
and
John Carmack's High Performance Propulsion Award, $1000 for designing a rocket motor better than a certain performance level
(Seems to be down, at the moment, try the Wayback Machine)
"An object declared as type _Bool is large enough to store the values 0 and 1." -- 6.1.2.5, C99 standard.