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#### DrRocket

##### Guest
MeteorWayne":2fhmg9tv said:
Have no idea, but I suspect like all intelligent lifeforms, they use metric

Unfortunately, because rockets need standard hardware like nuts and bolts and because most of the aerospace grade hardware comes from U.S, sources a great deal of the dimensioning on rockets is in English units. The military once tried to dictate the use of metric units and the result was a lot of thing like 2.54 cm bolts.

It is quite true that things are generally easier in the metric system. But it is an unfortunate truth that the English system is firmly entrenched.

Here is one that will drive you crazy. The standard figure of merit for rocket engines and propellant is specific impulse, Isp. It is the single most important number for a rocket motor. Isp is usually quoted in "seconds". What it really is momentum imparted per unit mass of propellant expelled (or thrust divided by the rate of mass expelled). So the units are (force x time / mass ) Now F= ma so the units are mat/m = at = velocity. HOWEVER, in English units this is bastardized to (lbf x seconds /lbm) where lbf is pounds-force and lbm is pounds-mass. Then one "cancels" the lbf in the numerator with lbm in the denominator to arrive at "seconds". Yes, that is really how the units of seconds for Isp come about.

It gets worse. Just when you think you understood F=ma you find that people want to use the units of mass as the lbm, rather than the correct English unit which is the slug. So when you bastardize the units of mass like that you wind up with F = 1/gc *ma where gc is 32.2. And you get to carry this gc thing around . So in English units like that with Isp in seconds in order to get delta velocity in fps from the rocket equation you wind up with

delta vel = gc*Isp*ln(final mass/initial mass)

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#### MeteorWayne

##### Guest
Holy carp!

Thanx for the enlightenment Dr R.

That's a really (sadly) funny and informative post.

I'll bet 99.99999% of English unit users don't even know that slugs are the unit of mass Maybe 99.9999999999% :ugeek:

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#### docm

##### Guest

Update

Thursday, May 14th, 2009

It's been an incredibly busy year so far at SpaceX and we continue to move full steam ahead. Of particular note are recent developments with respect to the Dragon spacecraft.

The image below shows the first joining of a full flight fidelity Dragon capsule and trunk section earlier this year on the manufacturing floor at our Hawthorne headquarters.

Standing over 23 feet tall in flight configuration, the stack included the Dragon qualification capsule and first flight trunk section, topped off with the carbon composite nose cap. The cap protects the spacecraft's common berthing mechanism ring, which enables it to join securely to the ISS, so that astronauts can access the interior of the capsule.

The trunk section then travelled to our Texas site where it completed structural testing in preparation for the first Dragon flight under the NASA COTS program, currently scheduled as the second Falcon 9 launch. During that flight, Dragon will make several orbits of the Earth, reenter the atmosphere and splashdown off the coast of Southern California. The gap between the capsule and trunk in the photo above will be filled by our lightweight, high performance PICA-X heat shield panels which will protect the capsule during reentry.

The engineering heat shield shown above has precisely machined test tiles fitted into place in their flight configuration. With 17 Dragon flights presently on our manifest, our PICA-X lab is operating non-stop to meet all our mission needs. SpaceX has come a long way since starting out in 2002 — all the way to Earth orbit. Our team now numbers over 700 and we're still hiring.

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#### mr_mark

##### Guest
Ok, let's take a look. It seems that they should have a full working Dragon by now if they are going to launch by years end? Delays in thruster and heatshield development have really set them back. And where are the openings for the solar panels in the lower casing?. This is basically a coke can with no coke in it. Since this was taken in January, I'm hoping they are now much farther along by now. It seems that Ares is about to pass them up. Well at least the Falcon 1 flight 5 rocket is ready to go in July along with the initial flight of Falcon 9 hopefully in August or September. I was really hoping the initial flight of Falcon 9 could launch before Ares1x in August. Now, I'm not so sure.

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#### Swampcat

##### Guest
mr_mark":2immsg9t said:
This is basically a coke can with no coke in it.

Well, as long as the "can" is functional it won't matter for the demos. The first demo only requires SpaceX to get it in orbit, maneuver and survive until recovery.

Also remember that the Ares I-X won't have a fully functional Orion on top of it either.

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#### ThereIWas2

##### Guest
According to the launch manifest, the first F9 launch does not really have a working Dragon on top. That goes on the second launch.

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#### Swampcat

##### Guest
ThereIWas2":f7vgojg4 said:
According to the launch manifest, the first F9 launch does not really have a working Dragon on top. That goes on the second launch.

That's correct. I was referring to the first COTS demo, not the first flight.

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#### hansolo0

##### Guest
Does anyone know if they're attempting to get the America space prize? (the 50 mil prize offered by bigelow??)

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##### Guest
hansolo0":39m4rx97 said:
Does anyone know if they're attempting to get the America space prize? (the 50 mil prize offered by bigelow??)
They're not eligible for the ASP, but they'll be very eligible for that fat delivery contract.

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#### hansolo0

##### Guest
Why aren't they eligible?? They're the only ones who even have a shot at it...(2 orbiting flights within 60 days?) :?:

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#### Swampcat

##### Guest
hansolo0":1e9lhvpk said:
Why aren't they eligible?? They're the only ones who even have a shot at it...(2 orbiting flights within 60 days?) :?:

They are ineligible because they accepted government money.

America's Prize Rules

1. The spacecraft must reach a minimum altitude of 400 kilometers (approximately 250 miles);
2. The spacecraft must reach a minimum velocity sufficient to complete two (2) full orbits at altitude before returning to Earth;
3. The spacecraft must carry no less than a crew of five (5) people;
4. The spacecraft must dock or demonstrate its ability to dock with a Bigelow Aerospace inflatable space habitat, and be capable of remaining on station at least six (6) months;
5. The spacecraft must perform two (2) consecutive, safe and successful orbital missions within a period of sixty (60) calendar days, subject to Government regulations;
6. No more than twenty percent (20 percent) of the spacecraft may be composed of expendable hardware;
7. The contestant must be domiciled in the United States of America.
8. The contestant must have its principal place of business in the United States of America;
9. The Competitor must not accept or utilize government development funding related to this contest of any kind, nor shall there be any government ownership of the competitor. Use in government test facilities shall be permitted; and
10. The spacecraft must complete its two (2) missions safely and successfully, with all five (5) crew members aboard for the second qualifying flight, before the competition’s deadline of Jan. 10, 2010[1]

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#### MeteorWayne

##### Guest
Based on the end date in # 10, it appears there will be no winner

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#### hansolo0

##### Guest
Well, option 10 seems highly unlikely, but option 9 definitely rules them out. I did not know govt' funding was forbidden. Too bad. Thanks Swampcat!

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#### frodo1008

##### Guest
That list is really kind of silly. THE major funding for anyone developing any kind of spacecraft capable of carrying human beings IS the government (and it further limits the funding to only within the US, so there goes any other governments funding also), at this time it is just to expensive for anyone to be otherwise!

It gets even worse when you look at that date on #10!

Move that date up by about a decade and you might just possibly find somebody to take this entire thing up, maybe.....

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##### Guest
frodo1008":3ndcczyg said:
That list is really kind of silly. THE major funding for anyone developing any kind of spacecraft capable of carrying human beings IS the government (and it further limits the funding to only within the US, so there goes any other governments funding also), at this time it is just to expensive for anyone to be otherwise!

It gets even worse when you look at that date on #10!

Move that date up by about a decade and you might just possibly find somebody to take this entire thing up, maybe.....
FYI, those rules were put in place in October 2004, right after the X Prize was won by Scaled Composites. Offer your own \$50 million prize & you can set your own rules, otherwise you'll just have to live by the "Golden Rule", "he who has the gold makes the rules." :mrgreen:

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#### frodo1008

##### Guest
I actually do not care one way or the other boris. However, I would guess that the rules were set up in 2004, and it was thought then that somebody such as spacex would either not have any governmental help, and/or be able to beat the 2010 deadline. I would now suspect the we will see a revision of that 2010 deadline at the very least!

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##### Guest
SpaceX delays launch
SpaceX's planned summer demonstration launch of the first Falcon 9 rocket has been delayed to the fall.
A combination of technical work and lack of documentation for the Air Force, which manages safety on the Eastern Range, created the delay. The launch has been scheduled for July and now will occur no sooner than October.
"It's basically dealing with the complexities associated with lifting a new rocket off from a new launch site," SpaceX President Gwynne Shotwell said.

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#### frodo1008

##### Guest
Well, after all the Air Force IS responsible for over all range safety at the Cape. So, I can imagine that when ULA wants to launch a brand new configurations, they also have to jump though the Air Force paperwork loops!

Not ALL governmental paperwork is just bureaucracy, it is sometimes necessary to keep people and property safe in a very highly reactive and unsafe industry such as major rocket launching!

Heck, this may even turn out to spacex's advantage, giving them more time to make sure that this all important launch goes well, if not perfectly!!!

I mean, the one sound that any investors in this area do NOT want to hear is KABOOM!

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#### astc

##### Guest
so what happens if Space X cant deliver,.. which I am guessing they cant.. would the y get sued by customers whose orders they have taken?

Anyone from Space X on this thread!!!

would love to know their opinions!!!

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#### MeteorWayne

##### Guest
Sounds like the comment of someone with an agenda.

You may guess they can't, I'm guessing they can. Don't you think it's a good idea to be careful and make sure everything is fine before launching? What has your company launched....I'll tell you what, nothing!

At the moment, you are a powerpoint presentation.

They are a heck of a lot further along than that; in fact further along than almost anyone else.

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#### astc

##### Guest
Dude,
Before you use such hard words ... maybe you should know more about us before commenting. Yes as ASTC we have not launched anything yet. But our partners have ...

And yes, you are right about us, wanting to know if there are jobs, we can try for... and if Space X cant deliver, many other companies , Like ISRO,Orbital and some other companies would be keen on!!!

Whats with our ppt? did we send you any.. lol..

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#### wtrix

##### Guest
astc":94sy6zhq said:
so what happens if Space X cant deliver,.. which I am guessing they cant.. would the y get sued by customers whose orders they have taken?

Anyone from Space X on this thread!!!

would love to know their opinions!!!

Any arguments or just dreaming loudly? What specifically makes you think that SpaceX can't deliver?

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#### astc

##### Guest
wtrix":348if0h1 said:
astc":348if0h1 said:
so what happens if Space X cant deliver,.. which I am guessing they cant.. would the y get sued by customers whose orders they have taken?

Anyone from Space X on this thread!!!

would love to know their opinions!!!

Any arguments or just dreaming loudly? What specifically makes you think that SpaceX can't deliver?

Lets hope, for my sake. i am not dreaming loudly... well.. it would be good if they can deliver. . . but since their delays and everything , I am a bit skeptical about them ..but i would like to see their launch for ATSB (Malaysia).

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#### MeteorWayne

##### Guest
astc":18sss0jl said:
Dude,
Before you use such hard words ... maybe you should know more about us before commenting. Yes as ASTC we have not launched anything yet. But our partners have ...

And yes, you are right about us, wanting to know if there are jobs, we can try for... and if Space X cant deliver, many other companies , Like ISRO,Orbital and some other companies would be keen on!!!

Whats with our ppt? did we send you any.. lol..

Surely you jest. Me with harsh words? You were the one suggesting that customers might sue (or should sue) SpaceX.

How many launches has your paper company (that's what I meant by powerpoint...you have plans but have actually accomplished exactly nothing) done? Zero. How many launches has SpaceX done? More than 1, which is 1000000000000000000000000000000000000000000000000000000000000...% more than yours has.

Who are your partners, so we can assess their records? I assume you can show they are really your partners, not just that you SAY they are your partners. Please demonstrate the partnership.

So far you have demostrated nothing. If that's not the case, please educate us.

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