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Author
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Topic: Shuttle Sonic booms
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Peter S
Member Posts: 101
From: Toronto, Ontario , Canada
Registered: Jan 2006
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posted 02-27-2006 08:22 PM
   
Hello all ; My son, (7 yrs old..) recently got a DVD called "IMAX - The Dream Is Alive", about the Shuttle program. (Good dvd too, albeit a tad short...)
Anyway, at the very beginning there is some footage of the Space center in Florida, and no sound , other than from the nature around the facility, until you hear 2 sonic booms, indicating the shuttle is coming home....(Then the footage of the orbiter landing comes in...) .
My little guy asked me the question, about the booms, and I explained to him what it was and why we hear it. Then he asked me why there were two of them ?
I hadn't thought that one through and I have to say I didn't know the answer to that.
Why are there 2 sonic booms? Peter S ------------------
Peter
Toronto, Canada [This message has been edited by Peter S (edited February 27, 2006).] |
jeffwilliams
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posted 02-27-2006 08:31 PM
From the NASA HSF Web site:As the space shuttle re-enters the atmosphere at supersonic speeds, it creates shock waves that produce sonic booms. There is a shock wave at the orbiter's nose and one at the orbiter's tail as it re-enters These shock waves are created when the pressure disturbances caused by the shuttle flying through the air cannot escape the shuttle. These pressure waves travel at the speed of sound, but the shuttle is flying faster than the speed of sound, so a wave of pressure builds up along the nose and tail. As the shuttle altitude decreases, these pressure waves intersect the ground with a large pressure delta that your ears detect as a boom. In fact, you'll hear not one, but two sonic booms! Because the space shuttle is so large, 37 meters (122 feet) long, you will hear the sonic booms created by both the nose and tail shock waves, which occur about one-half second apart. All supersonic airplanes produce two sonic booms, but because they happen so close to each other, you hear them as one sound. This Web site has some good pictures and a discussion of this subject: http://www.galcit.caltech.edu/SonicBoom/boomprimer.html
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Peter S
Member Posts: 101
From: Toronto, Ontario , Canada
Registered: Jan 2006
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posted 02-27-2006 08:35 PM
Thanks Jeff.... You're a Legend ! Peter S ------------------
Peter
Toronto, Canada |
Rob Joyner
Member Posts: 1308
From: GA, USA
Registered: Jan 2004
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posted 02-28-2006 01:18 AM
Please correct me if I'm wrong, but I've heard there are actually three, though only two are heard. The first from the nose, the second from the wings and the last from the tail.
Because the wings and tail are so close together, the booms are heard at the same time. |
Ashy
Member Posts: 157
From: Preston, England
Registered: Mar 2004
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posted 02-28-2006 08:37 AM
So would you hear a sonic boom at take off if you were ahead of the shuttle.?Si |
lunarrv15
Member Posts: 1355
From: Cincinnati, Ohio, Hamilton
Registered: Mar 2001
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posted 02-28-2006 11:25 AM
is the shuttle over Florida when the boom boom's?Was at the cape when the shuttle had clearance for landing with Glenn. The sonic boom shuttle creates is felt through ground and air |
Rizz
Member Posts: 1208
From: Upcountry, Maui, Hawaii
Registered: Mar 2002
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posted 02-28-2006 12:27 PM
Heres a link to a shot of the shock wave created by one of the shuttles.NASA has a clearer shot, I don't recall the mission, maybe Ben does.
http://www.anomalies-unlimited.com/Odd%20Pics%202/Images/shuttlesonic.jpg |
katabatic
Member Posts: 72
From: Oak Hill, VA, USA
Registered: Jun 2005
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posted 02-28-2006 01:25 PM
It's upside down...  Oops, I mean it's rotated 90 degrees to the right.... [This message has been edited by katabatic (edited February 28, 2006).] |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 02-28-2006 02:42 PM
STS-106 Atlantis. It's a video frame:
http://www-pao.ksc.nasa.gov/kscpao/images/medium/00pp1416-m.jpg The condensation shockwave (occasionally seen on fighter jets too) is not technically a product of going super sonic, but always occurs at or close to it. It is dependent on humidity conditions, acceleration, pressure, etc. The shuttle does produce a sonic boom on the way up, but it's drowned out by the launch. |
mjanovec
Member Posts: 3811
From: Midwest, USA
Registered: Jul 2005
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posted 02-28-2006 03:10 PM
If one watches the Project Gemini DVD set from Spacecraft Films, there is one launch where the audio runs long enough to hear a very audible sonic boom. The Titan must be "quiet" enough that the sonic boom is clearly audible.It's my favorite launch sequence, as you can also hear several spectators hooting and hollaring their approval. I just can't remember right now what Gemini mission it can be found under. |
ejectr
Member Posts: 1751
From: Killingly, CT
Registered: Mar 2002
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posted 02-28-2006 03:36 PM
I was at the STS-95 launch and actually heard the sonic boom.My buddy was video taping it and it is very plain and clear on the audio. |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 02-28-2006 04:15 PM
No launch is "quiet" :-) but I will check out the DVD tonight and see.As for STS-95, I would be surprised that you could pick out a boom with all the crackling and, well booming, that occurs during a launch. I would be interested in seeing the video if its digitized. By the way, a sonic boom is not produced by a vehicle *breaking* the barrier, but actually occurs on any vehicle passing at, above or through the speed of sound. When you hear the Shuttle's boom on entry, you are hearing it as the wave passes your particular location; someone a mile away from you will not hear it until the wave passes over them. In otherwords, there is not one boom that is emitted at one particular time (as in when it passes below the sound barrier) which everyone hears at once. Anyone along the Shuttle's path from the point when it is well into the atmosphere (let's say anyone in Florida for ISS flights) will hear the booms as it passes by, even when the Shuttle is still going Mach 5 or more. |
Ashy
Member Posts: 157
From: Preston, England
Registered: Mar 2004
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posted 02-28-2006 05:37 PM
I videoed the launch of STS107 and never heard any boom, which was why I asked if could you hear it on launch. That said, there was alot of other noise that could have masked it.Si |
ejectr
Member Posts: 1751
From: Killingly, CT
Registered: Mar 2002
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posted 02-28-2006 07:01 PM
The video is on a VHS tape. I heard the sonic boom and you can easily point it out at the same point in time on the tape.Maybe someone's hearing at times is just a bit more capable than another's hearing. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 02-28-2006 07:26 PM
According to former shuttle technician Kim Keller in a 2003 post to sci.space.shuttle, it is technically impossible to hear the boom: quote:
The shock wave extends out radially from the vehicle and is "towed" along by the vehicle. Since the vehicle is pointed up and moving away from observers, you'd never hear the sonic boom of the shock wave. If you happened to be at an altitude where the shuttle was supersonic, then you would hear it as it climbed past you.
Though, he could be wrong... one test would be to know how many seconds into launch you hear the boom. We know the rate of climb (or at least can figure it out) and can calculate exactly when the boom should have occurred, the distance from the pad the shuttle was at that instant and how long it would take the sound to reach your camcorder.[This message has been edited by Robert Pearlman (edited February 28, 2006).] |
newsartist
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Registered:
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posted 03-05-2006 07:46 PM
Sonic booms from climbing rockets may reflect or bend off inversion layers or other atmospheric things.I have heard distinct booms from a few, of many, sounding rockets launched about a mile away. Because they were unexpected, I have no clue to the timing, but they 'felt' like they were later than they should have been. We talked about booms on another forum, and I realized that probably few people alive today have ever heard one, (excluding carrier crews.) When I was growing up in the '50s, we got them about every day, some pretty solid bangs too! Perhaps, for the 60th of Yeagers first Mach run, a high boom could be done at Oshkosh? [This message has been edited by newsartist (edited March 05, 2006).] |
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