wardialer
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Vert. Speed Of Space Shuttle

Thu Nov 15, 2001 2:35 pm

What is the vertical speed of the space shuttle during launch between 100 to 50,000 feet ?
 
XFSUgimpLB41X
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RE: Vert. Speed Of Space Shuttle

Thu Nov 15, 2001 2:37 pm

It breaks Mach 1 going nearly straight up going through just a few thousand... if thats any idea. I'd love to see some exact figures of it's acceleration myself too.
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flyf15
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RE: Vert. Speed Of Space Shuttle

Thu Nov 15, 2001 4:53 pm

Here are some of the approximate altitude/time numbers for the Saturn V on a typical Apollo moonshot (gives you an idea for the space shuttle).

Altitude: Time after launch
10000ft: 42sec
20000ft: 59sec
30000ft: 72sec
40000ft: 82sec
50000ft: 90sec
65000ft: 99sec
80000ft: 107sec
100000ft: 119sec

Somebody else can work out the speed/acceleration...I'm off to bed  Smile/happy/getting dizzy
 
UPS763
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RE: Vert. Speed Of Space Shuttle

Fri Nov 16, 2001 9:44 am

The Shuttle clears the tower much faster then the Saturn did.

Matthew
 
lehpron
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RE: Vert. Speed Of Space Shuttle

Fri Nov 16, 2001 11:58 am

You should check NASA's site for anymore info. As I recall from a *.gif on their site:

The shuttle experiences a 1.5g-liftoff acceleration (1 to overcome it's weight and .5 for straight up acceleration), just before boosters fall away it feels nearly 9g's and then drops to 4g's afterwards, and goes up to 7g's right before the tank falls away. All in all, it takes around 15 minutes to get to an orbital speed of 5 miles per second.

I'm definitely sure the Shuttle passes though M5.0 by the time the boosters fall away two minutes in. BTW, a "g" is the acceleration due to gravity which is like zero to 60mph in 3 seconds.

Also since the acceleration changes because of change in mass, it's hard to figure exactly when it's at what speed. I guess you can assume they are somewhat parabolic if yyou made a graph of speed vs. accel.

Good enough 4 ya?  Big thumbs up
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XFSUgimpLB41X
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RE: Vert. Speed Of Space Shuttle

Fri Nov 16, 2001 1:47 pm

1G is 9.81 m/s squared.
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POSITIVE RATE
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RE: Vert. Speed Of Space Shuttle

Sun Nov 18, 2001 12:31 pm


I managed to find some Data on the space shuttle:

Rate of climb at 130,000 ft: 132,000 FPM
Cruise speed(in orbit): 14,800 kt
Orbital Altitude: 100/312 nm
Landing ground roll: 10,000 ft
Vso: 150 kt
Vne: 333 kt
Vlo: 312 kt
Va: 185 kt
Vld: 185 kt
Lift-to-drag glide ratio hypersonic: 1.05
Subsonic: 5.1
 
airplay
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RE: Vert. Speed Of Space Shuttle

Sun Nov 18, 2001 2:31 pm

Lehpron,

Any information I've read about the shuttle indicates that acceleration never exceeds 3 Gs.

Am I missing something?


 
lehpron
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RE: Vert. Speed Of Space Shuttle

Mon Nov 19, 2001 1:22 pm

Well consider that the F=ma rule will apply all the way though out the launch phase: Meaning, as the fuel is ejected, the vehicles' (orbiter, tank, boosters) get lighter but there's still the same thrust. Plus that as they go up the air is thinner so there is less drag. Also the farther you are from the earth the force of gravity drops. That leaves only one component to change, acceleration, which will skyrocket until force level drops and/or mass gets dumped.

Personally, I think the 3g's is an average; NASA's website has become too complicated, I can't find the pix that showed the acceleration curves w.r.t time. Ah!
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
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RE: Vert. Speed Of Space Shuttle

Mon Nov 19, 2001 1:28 pm

Airplay i thinks you are correct 3G is the max G force experienced during a shuttle launch if i remember right. Anymore than this and structural failure would probably occur as opposed to a Saturn V launch or a Gemini Titan which went 7-8 G's!
 
airplay
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RE: Vert. Speed Of Space Shuttle

Mon Nov 19, 2001 2:50 pm

Lehpron,

Yes...you are correct. F=ma. But the engines on the space shuttles are "throttlable". So "F" can (and does) change at different stages of the launch.

 
lehpron
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RE: Vert. Speed Of Space Shuttle

Mon Nov 19, 2001 6:39 pm

Yes, but most of the thrust @ L/O is from the SRB's.

They are a "one-time-only" engine and that near the end of their burn, they have the same thrust and are light as hell so the orbiter definitely experiences a very high accel prior to jetisoning the SRB's. Afterwards there is less mass and less thrust yet it's enough to keep the rest on course.

The shuttle's main engines are throttled but keep in mind: Before the tank is jetisoned the main engines have a over a million lbs. thrust against a glider and tank.
The meaning of life is curiosity; we were put on this planet to explore opportunities.
 
lehpron
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RE: Vert. Speed Of Space Shuttle

Wed Nov 21, 2001 8:37 am

Airplay, I just figured something. That 3g-limit you were talking about could be the structural max as a loaded force on the fuselage, i.e. turn radius force. Most airliners max out between 2 - 3g's and military fighter go into the higher force loads.

When I was refering to g-loads, I meant the acceleration due to engine thrust against the body not turn radius. Also I did an approx. calculation on the Shuttle's g-loads:

Liftoff: 1.2g's
Prior to SRB jetison: 5.5g's
After jetison (orbiter and tank only): 1.5g's
Prior to tank jetison: 3.5g's

I think I mistakenly used the numbers of the Saturn V instead of the Shuttle, sorry.

Wardialer, read this to find you various answers:

I used this formula in my Dynamics book:

F=ma=ve(mf/t), where ve is the exhaust velocity and mf is mass of fuel (kg/s) which is the rate of fuel dumped. Remember that since the fuel is constantly dumped out the mass will continue to drop, hence higher accel and as time goes by a hell of a lot higher speed.

v(rocket)=(accel)(time)=[ve(mf/t)/(m-mf)]t

have fun  Big thumbs up
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A380X4TRENT900
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RE: Vert. Speed Of Space Shuttle

Thu Mar 09, 2006 9:44 pm

PUT IT THIS WAY - THE SHUTTLE IS DOING 160KM/H JUST BEFORE IT CLEARS THE TOWER......

THAT'S DAMN FAST ACCELERATION - FASTER THAN MOST CARS.

THE TOWER IS ONLY ABOUT 100 METRES HIGH!
 
David L
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RE: Vert. Speed Of Space Shuttle

Thu Mar 09, 2006 10:30 pm

Quoting A380X4TRENT900 (Reply 13):

Whoa there! You don't need to shout!  Smile
 
chksix
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RE: Vert. Speed Of Space Shuttle

Thu Mar 09, 2006 10:47 pm

ALL CAPS....

From:
http://science.ksc.nasa.gov/shuttle/...-newsref/sts-mps.html#sts-mps-ssme

Quote:
The SSME thrust level depends on the flight: it may be 100 percent or 104 percent for some missions involving heavy payloads or may require the maximum thrust setting of 109 percent for emergency situations. The initial thrust level normally is maintained until approximately 31 seconds into the mission, when the GPCs throttle the engines to a lower thrust to minimize structural loading while the orbiter is passing through the region of maximum aerodynamic pressure. This normally occurs around 63 seconds, mission elapsed time. At approximately 65 seconds, the engines are once again throttled to the appropriate higher percent and remain at that setting for a normal mission until 3-g throttling is initiated.

The solid rocket boosters burn out at approximately two minutes, mission elapsed time, and are separated from the orbiter by a GPC command sent via the mission events controller and by the SRB separation PICs. The flight crew can initiate SRB separation manually if the automatic sequence fails; however, the manual separation sequence does not bypass the separation sequence logic circuitry.

Beginning at approximately seven minutes 40 seconds, mission elapsed time, the engines are throttled back to maintain vehicle acceleration at 3 g's or less. Three g's is an operational limit devised to prevent physical stresses on the flight crew. Approximately eight seconds before main engine cutoff, the engines are throttled back to 65 percent.

More here:
http://science.ksc.nasa.gov/shuttle/...newsref/sts_mes.html#mes_1st_stage
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TheSonntag
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RE: Vert. Speed Of Space Shuttle

Thu Mar 09, 2006 11:43 pm

Ok, lets calculate the average acceleration (it has been some years since I had physics last time)

100000ft: 119sec

100000 = 1/2 * a * 119² + a * 119

200000 = a * 14161 + a * 238

200000 = a * 14399

a = 13, 889 feet/s²

Did I do anything wrong? That seems slow, but I only calculated the altitude, maybe it would be correct to calculate the distance, too...

[Edited 2006-03-09 15:45:26]
 
Mich
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 12:09 am

Distance has to be calculated as the shuttle does not go straight up, just after clearing the tower the shuttle does a roll with the belly toward the sky. If you look at a takeoff picture the exhaust gases form a 90 degree arch. So at 100,000 feet it can be 100 miles down range.
 
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Starlionblue
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 12:20 am

Quoting UPS763 (Reply 3):
The Shuttle clears the tower much faster then the Saturn did.

Thanks to the firecrackers.

Quoting TheSonntag (Reply 16):

a = 13, 889 feet/s²

Did I do anything wrong? That seems slow, but I only calculated the altitude, maybe it would be correct to calculate the distance, too...

Sounds about right to me. Almost 1.5G average. If you sustain that for 15 minutes or so you're going pretty fast.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
TheSonntag
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 12:52 am

Ok, so if we assume it is correct, the vertical speed after 119 seconds will be:

119 * 13,889 = 1652,791 feet/seconds. That is more than 500 metres/second or more than Mach 1,3. Not bad at all...
 
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Starlionblue
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 3:02 am

Quoting TheSonntag (Reply 19):
Ok, so if we assume it is correct, the vertical speed after 119 seconds will be:

119 * 13,889 = 1652,791 feet/seconds. That is more than 500 metres/second or more than Mach 1,3. Not bad at all...

Except that actually sounds way too low for 2 minutes.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
KELPkid
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 4:22 am

Whoa...how does a thread survive 5 years without a post?  spin 
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XFSUgimpLB41X
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 4:35 am

I think mr. A380blahblahblah had a few too many drinks last night....
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TheSonntag
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 6:01 am

Quoting Starlionblue (Reply 20):
Except that actually sounds way too low for 2 minutes.

Well, this is only the vertical speed. The airspeed certainly is much higher I would guess. If the shuttle went straight up and were still above the cape it would be too low, but since it also travels into another direction, I guess it might be a correct number... Any Nasa engineers here who could give the real data?
 
prebennorholm
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 7:15 am

Quoting Lehpron (Reply 12):
Liftoff: 1.2g's
Prior to SRB jetison: 5.5g's
After jetison (orbiter and tank only): 1.5g's
Prior to tank jetison: 3.5g's

"Prior to SRB jetison: 5.5g's" is not correct.

The SRB thrust is reduced as fuel is burned. 50 seconds into the flight (or roughly half way into the SRB burn) the thrust has been gradually reduced from some 3.3M lbs to 2.2M lbs (reduced 33%).

That means that the acceleration never really exceeds 3.5g's.

That preprogrammed "throttle" on the SRBs is produced the following way:

The central hole in the solid fuel is made up as an 11-point star. That gives a much greater burning fuel surface in the beginning. But as the spikes of the star are gradually burned away, then the burning surface - and consequently the thrust - is reduced.

One of the most important design requirement of the Shuttle system was that it should be able to fly with "passengers", or scientists without exceptional physical capabilities, even elderly people. Therefore the low g limit.

If memory treats me well, then the first US orbiting astronaut John Glenn enjoyed a Shuttle passenger flight at age 70.

I remember very well the very first Shuttle flight - next month 25 years ago. There was a TV downlink showing commander John Young studying a manual or checklist. One journalist noticed that John Young was wearing glasses. He asked if NASA really spent billions on launching the Shuttle with people without perfect eyesight?

NASA answered that Mr. Young is the perfect astronaut, but at fifty he is no teenager any more, and elderly people need reading glasses.
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Starlionblue
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 7:56 am

Quoting TheSonntag (Reply 23):
Quoting Starlionblue (Reply 20):
Except that actually sounds way too low for 2 minutes.

Well, this is only the vertical speed. The airspeed certainly is much higher I would guess. If the shuttle went straight up and were still above the cape it would be too low, but since it also travels into another direction, I guess it might be a correct number... Any Nasa engineers here who could give the real data?

Ah good point.

Quoting Prebennorholm (Reply 24):

I remember very well the very first Shuttle flight - next month 25 years ago. There was a TV downlink showing commander John Young studying a manual or checklist. One journalist noticed that John Young was wearing glasses. He asked if NASA really spent billions on launching the Shuttle with people without perfect eyesight?

NASA answered that Mr. Young is the perfect astronaut, but at fifty he is no teenager any more, and elderly people need reading glasses.

I remember that Young's pulse was in the 80s or so just before launch, while Crippen's was over 135! So much for old astronauts! Big grin BTW Young stayed qualified to fly until well into his 70s.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
David L
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 9:28 am

Quoting Prebennorholm (Reply 24):
The central hole in the solid fuel is made up as an 11-point star. That gives a much greater burning fuel surface in the beginning. But as the spikes of the star are gradually burned away, then the burning surface - and consequently the thrust - is reduced.

Cunning!
 
Slcpilot
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 2:19 pm

What are the odds? TODAY (!) I saw an SRB firing for the first time. Here's a clip of video....

http://reinman.net/Shuttle!.wmv

It was not as loud as expected, but much brighter. The exhaust plume melted quite a bit of snow off the mountain. By my estimates, we were a little less than two miles away from the stack, but I haven't measured it yet.

SLCPilot

[Edited 2006-03-10 06:23:01]
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vikkyvik
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 2:44 pm

Quoting SLCPilot (Reply 27):
What are the odds? TODAY (!) I saw an SRB firing for the first time.

That's awesome. Do they do those demos around the country?

Quoting SLCPilot (Reply 27):
By my estimates, we were a little less than two miles away from the stack, but I haven't measured it yet.

I counted about 8-9 seconds between the firing and the sound. A bit under 2 miles.

~Vik
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oly720man
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RE: Vert. Speed Of Space Shuttle

Fri Mar 10, 2006 11:01 pm

There are some velocities at times here

http://www.aerospaceweb.org/question/spacecraft/q0183.shtml
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TheSonntag
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RE: Vert. Speed Of Space Shuttle

Sat Mar 11, 2006 12:01 am

Quoting Oly720man (Reply 29):

Thank you, in fact it shows the calculations above were not that far from being correct. The vertical velocity is high, but not as high as one might think, because the shuttle isn't going straight up.

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