Tim Dodd and Elon Musk tour and interview Pt. 3

tahanson43206 · 2021-08-15 18:01:45

For SpaceNut .... your comments in post #50 seem to imply (at least as I read it) that SpaceX is lazy and unwilling to do extra work, such as moving equipment by barge to a launch site.

The environmental impact studies (on the other hand) may ** indeed ** be a problem.

On the third hand ... a permanent sound can be generated at the offshore platforms to irritate fish so they move away from the area.

There is probably a limit to how far the scientists at Environmental Protection Agency are willing to go in this situation.

(th)

kbd512 · 2021-08-15 21:00:33

GW,

If each tanker flight costs $2M, then SpaceX can afford 75 tanker flights for the purchase price of 1 Atlas V mission, or 1,000 tanker flights for each SLS launch. If we launch a thousand ships and still can't do a lunar mission, someone really needs to have a chat with the mission planning group. Carrying lots of gas to orbit is obviously not ideal, but when the only alternatives are as absurd as SLS is, then almost any mission with in-flight refueling, even 10 of them, looks budget-friendly by way of comparison. If we manage to harvest O2 from the upper atmosphere, then the only liquid that needs to be carried to orbit is fuel, and O2 is 2/3rds of the propellant mass. The same applies on Mars. Some of the O2 to come home could be provided by CO2 from the upper atmosphere of Mars, with water ice from nearby objects supplying the H2O to make the CH4. One way or another, I'm pretty sure that someone at SpaceX will figure this out.

kbd512 · 2021-08-15 21:02:16

tahanson43206,

tahanson43206 wrote:

There is probably a limit to how far the scientists at Environmental Protection Agency are willing to go in this situation.

Never underestimate how far someone who sincerely believes they're "doing the right thing" is willing to go. There is no end to the torment from people who truly believe in what they're doing to others.

GW Johnson · 2021-08-16 08:21:50

There's always harm to wildlife and discharge of pollutants as issues in any EPA environmental impact statement. These generally provide opportunities for bureaucrats to stall things, yes, but they are not the top priority.

Life and safety of the public are the very top priority. That's why I keep bringing up the lethal levels of noise for unprotected folks not inside a heavy bunker, and the very real threat of explosion and fire for quantities of deflagrating propellants in the thousands of tons.

While the decision predates the existence of the EPA, these very same top-priority risks are a very large part of why NASA did not ask Von Braun to build his Nova design to go to the moon. They went with his Saturn-5 design, to limit the risks of lethal noise and incredibly-powerful explosions.

In the early 1960's when this decision was made, Von Braun had paper designs for all the Saturns and Novas. They decided to go with his Saturn-1 and Saturn-5 designs as acceptable risks for noise and explosion, and set the 3 mile (5 km) radius for the exposed human exclusion zone.

GW

louis · 2021-08-16 17:13:23

I think in terms of noise and pressure impact, marine life might well be more adversely affected than life on land.

SpaceNut wrote:

That would mean barging the parts to the launch site since building the assemblies at the site would be even more difficult and there is still the environmental impact studies which would also make the noise on the water a killing zone for marine animals.

louis · 2021-08-16 17:18:18

Noise attentuation technology must have moved on since the 1960s!

I will be surprised if Musk and co. haven't been working on this.

Cape Canaveral, as I recall is very flat and open, as if they couldn't be bothered to make much of an effort.

Surely you want to create some shock wave absorbing barriers around the launch site.

I was talking to a friend the other day about how walled gardens can be so quiet, even in big cities. Surely, it's the same issue here.

GW Johnson wrote:

There's always harm to wildlife and discharge of pollutants as issues in any EPA environmental impact statement. These generally provide opportunities for bureaucrats to stall things, yes, but they are not the top priority.
Life and safety of the public are the very top priority. That's why I keep bringing up the lethal levels of noise for unprotected folks not inside a heavy bunker, and the very real threat of explosion and fire for quantities of deflagrating propellants in the thousands of tons.
While the decision predates the existence of the EPA, these very same top-priority risks are a very large part of why NASA did not ask Von Braun to build his Nova design to go to the moon. They went with his Saturn-5 design, to limit the risks of lethal noise and incredibly-powerful explosions.
In the early 1960's when this decision was made, Von Braun had paper designs for all the Saturns and Novas. They decided to go with his Saturn-1 and Saturn-5 designs as acceptable risks for noise and explosion, and set the 3 mile (5 km) radius for the exposed human exclusion zone.
GW

SpaceNut · 2021-08-16 18:59:48

The star-port is flat and devoid of any barriers for sound blocking just like Nasa's launch pads are....

RobertDyck · 2021-08-16 20:36:03

louis asked if Musk & Co are already working on noise attenuation. I said they already are. The orbital launch platform is way up in the air. It isn't just high enough for rocket engine exhaust, it's a tall stool. That's to give exhaust time to dissipate into the atmosphere before it impacts the ground. Full force hitting the ground will reflect sound waves, creating resonance between ground an engine. Saturn 1B launched from Launch Complex 34, with a concrete ring just high enough for an exhaust diverter. Saturn V launched from LC 39, which included a mobile launcher just high enough for the transporter, and the launch pad had concrete flow channels that redirected exhaust to the side. when Saturn 1B launched for Skylab, they added a "milking stool" to the mobile launcher. That raised the rocket enough that exhaust had time to attenuate. The SpaceX orbital launch platform is like that "miking stool", it's high up.

In the interview with Tim Dodd, Elon also said they're "considering" a deluge system as well.

GW Johnson · 2021-08-17 08:16:53

The water deluge has a sound-deadening effect, yes. But it is really there to keep the concrete and steel from being washed away by the exit jets from the engines. The hypersonic cores of the 5 F-1 engines on the Saturn 5 extended multiple vehicle lengths behind the vehicle. The flame tunnel with the shockdown elbow turn did more for sound suppression than the deluge did. The deluge was there for the flame tunnel structures to survive. It just turned out to lower the sound further. But even with all that, no spectators (civilian or NASA) were allowed to be outside any closer than 3 miles.

As for being high up on a "milking stool", that makes the sound carry further. The line of sight from source to ear is clearer of surface obstructions. The loudest noise Spacex has ever made at McGregor was Grasshopper's self destruct explosion 2000-ish feet in the air. The second-loudest is when they fire something atop the tower stand they inherited from Andy Beasley.

GW

tahanson43206 · 2021-08-17 09:10:37

The discussion of sound management is of interest to a wider audience than those who are interested in space launches...

A local entrepreneur wanted to build an automobile race track right in the center of down town in a nearby city. The objections from residents who currently "enjoy" just the normal level of background noise from freeways was long and loud, and the entrepreneur responded by hiring consultants to try to mitigate the sound. I'd have to go back to review the details if anyone is interested, but among the proposals was a 30 foot wall.

I distinctly recall an objection to ** that ** idea that sound bends over the top of such an obstacle and spreads to the nearby terrain.

The entire discussion reveals (not that a reminder is needed) that (at present) humans lack an effective sound attenuation system suitable for deployment in situations like this.

The propagation of energy from one molecule to another represents an opportunity for a ** really creative ** thinker to absorb energy and convert it to something useful, like a flow of electricity.

The scale of machines capable of absorbing energy from moving molecules is (obviously) on the nano-scale. We've had visions of such machines for many decades now, but (to the best of my knowledge) only the medical folks are dabbling in that arena. Fortunately, ** they ** are having some success.

This same discussion is closely linked to the challenge of absorbing energy from molecules that are disturbed by spacecraft attempting to penetrate a volume of space already occupied by molecules of various kinds. The default behavior is to allow the elastic properties of the molecules to express themselves by bouncing away from the approaching spacecraft and bothering all their neighbors, who collectively become engorged with vibrating energy.

The solution available to that ** very creative ** thinker imagined above is to capture the molecules before they have a chance to escape and bother their neighbors.

Whatever mechanism can absorb energy from molecules disturbed by sound should be able to prevent unwanted disturbance of molecules in the path of an arriving spacecraft.

(th)

Calliban · 2021-08-17 10:07:22

tahanson43206 wrote:

The propagation of energy from one molecule to another represents an opportunity for a ** really creative ** thinker to absorb energy and convert it to something useful, like a flow of electricity.
(th)

This is exactly how a microphone works. A permanent magnet oscillating within a surrounding copper coil and inducing a current. Something like this is unlikely to ever provide a lot of energy, but there are niche applications where it might be useful. A microphone could generate enough current to power a speaker built into a telephone headset. No supplemental power supply is needed to carry the signal. The advantage that this arrangement is high reliability. There are circumstances where very simple, reliable and robust communication systems like this are necessary.

Last edited by Calliban (2021-08-17 10:08:15)

tahanson43206 · 2021-08-17 10:21:22

For Calliban re #61

Bravo! Thanks for giving this branch of the original topic support!

If others find it worth pursuing, we might be able to develop a topic dedicated to the proposition that sound energy might be harvested as both a way to mitigate loud noise situations, ** and ** as a way to generate useful electricity.

(th)

RobertDyck · 2021-08-17 10:37:42

A simple way to contain sound is to put it in a sealed box. A rock concert in a closed arena will contain sound, a concert in an open air stadium will carry. Any break in the air tight seal with allow sound to escape. Obviously that won't work for a rocket launch, because the rocket has to ascend. Water deluge is a way to contain the exhaust in water. Yes, it also ensures the hot exhaust doesn't decompose the concrete. Supersonic or hypersonic exhaust will slow rapidly in water. Sufficient water will dampen vibrations, but it takes a lot. A deluge system fills the space beneath the rocket with liquid water, it's not a light mist.

Realize "diamonds" in exhaust from a fighter jet are supersonic exhaust impacting the "wall" of subsonic or static air. The shock wave bounces back and forth creating diamonds. Eventually the supersonic exhaust slows to subsonic speed, which then mixes with air. That's where diamonds stop. If the water deluge system can disrupt supersonic exhaust flow (or hypersonic) before it hits the concrete pad, it would reduce noise.

Calliban · 2021-08-17 11:04:03

There are many similar examples. Watches are often powered by the kinetic movement of its wearer. Calculators powered by background light. Clocks and lights powered by falling weights. Torches powered by winding or kinetic movement.

Many applications require only very small quantities of electric or mechanical power and can make use of whatever energy source is most conveniently available. The driving requirements are reliability and simplicity at a whole system level.
Consideration of EROI is less important because the total energy consumption of the device is negligible and the embodied energy of other supporting equipment (like a charger and supporting grid connection) would overwhelm any other possible energy savings.

I often think that many mechanical devices have become overcomplicated. Telephones now require supplemental electric power and are overloaded with electronics. We use electric drills where a brace or hand operated drill would do. Electric saws instead of hand saws. Mechanical nail guns instead of hammers. Fit bits that need charging, rather than watches and common sense. Maybe Mars will be the fresh start needed to cut back on this sort of overcomplication. Often overcomplicated devices like this are developed not because anyone desperately needs them, but because manufacturers desperately need to sell something. They become unwanted Christmas or birthday gifts that you never knew you wanted, when people run out of stuff to buy you.

Last edited by Calliban (2021-08-17 11:09:06)

RobertDyck · 2021-08-17 11:08:10

An off-shore platform could simply be open to the water of the Gulf of Mexico. Rather than a water deluge system, let the waters of the Gulf absorb the shock diamonds.

tahanson43206 · 2021-08-17 11:20:26

Whales (I understand) were able to communicate over thousands of miles, before humans cluttered up the ocean soundscape with vessels and military activity.

I would expect a launch of a Super Heavy from a Gulf platform to be audible to whales and other similarly sound sensitive creatures on the far side of the planet.

Calliban seemed (to me at least) to be pointing toward a possible way to collect otherwise wasted energy from the sound waves near a launch.

Newton says that ** every ** erg that pushes Super Heavy toward the sky will be equally distributed as disturbance of the matter below.

(th)

RobertDyck · 2021-08-17 11:24:58

Calliban: as a technician, I've encountered other technicians who want to use a cordless drill as a power screwdriver. When we replaced computers used as cash registers, called Point-Of-Sale systems, for a major retailer. The mount for the debit card machine used security screws. When I tried to use a cordless drill, I snapped the screw head. It's not a normal screw, we didn't have anything to replace it. I was able to make do without, but stopped using a cordless drill. One lead technician wanted me to learn how to adjust the drill clutch to prevent that, but instead I just use a normal screwdriver. For debit card machines, I have a nut driver that fits screw driver bits including security bits. Doing it by hand means I can feel how much force, so don't snap anything. For other parts, messing with a cordless drill takes more effort than just using a screwdriver. To put it in terms a millennial can understand, a screwdriver has two speeds. If you hold the handle you get low speed and high torq, and if you spin the screwdriver shaft by rolling your fingers along the shaft you get high speed and low torque. I could deal with machine screws for POS system installations faster with just a screwdriver. I also found with really stuck screws, I can actually generate more torque with my hand on the handle of a screwdriver than the highest setting of a cordless drill.

In 2008-2009, I worked as a computer technical in a shop. They had special purpose power screwdrivers. They're smaller than a cordless drill. Messing with the battery and trying to fit those things inside the case of a desktop or tower computer is far more trouble than they're worth. No one used them.
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#51 2021-08-15 18:01:45

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#52 2021-08-15 21:00:33

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#53 2021-08-15 21:02:16

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#54 2021-08-16 08:21:50

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#55 2021-08-16 17:13:23

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#56 2021-08-16 17:18:18

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#57 2021-08-16 18:59:48

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#58 2021-08-16 20:36:03

Re: Tim Dodd and Elon Musk tour and interview Pt. 3

#59 2021-08-17 08:16:53

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#60 2021-08-17 09:10:37

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#61 2021-08-17 10:07:22

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#62 2021-08-17 10:21:22

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#63 2021-08-17 10:37:42

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#64 2021-08-17 11:04:03

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#65 2021-08-17 11:08:10

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#66 2021-08-17 11:20:26

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#67 2021-08-17 11:24:58

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