Author Topic: General Falcon and Dragon discussion (Thread 12)  (Read 432060 times)

Offline Jim

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #340 on: 04/30/2015 01:35 pm »

Clearly a concern, but not a show-stopper.  Any induced strikes are much further away than the existing lightning protection towers, so any EMP and induced voltages should be much less than the rocket already has to withstand.


Just hand wave it away.  Should have expected that was going to be the response. 

A.  Not true.  The towers are not 100% insurance. 
b.  And they are not going to install sensors on the spacecraft

Offline LouScheffer

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #341 on: 04/30/2015 07:22 pm »

Clearly a concern, but not a show-stopper.  Any induced strikes are much further away than the existing lightning protection towers, so any EMP and induced voltages should be much less than the rocket already has to withstand.


Just hand wave it away.  Should have expected that was going to be the response. 
You are completely correct.  A handwaving response is far too serious a reply to a one-sentence, arm-waving, unsubstantiated assertion of a problem, but it's perfectly normal for NSF.
Quote
A.  Not true.  The towers are not 100% insurance. 
True, but from google maps it looks like the towers are about 150 meters from the pad.  Here we are talking at least a kilometer away, a factor of 6 further.   Any effects will be reduced by at least this factor, and more like a factor of 36 for radiated effects.

In terms of experience rather than analysis, do you know of any cases where a strike at least a kilometer away caused damage to a spacecraft due to induced voltage/EMP?

Quote
b.  And they are not going to install sensors on the spacecraft
Agreed.  The sensors would go on the pad, to measure how the rocket/payload might be affected.  If the disturbance, as measured at the rocket, is within the design specs, it should be safe to proceed.

Offline guckyfan

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #342 on: 04/30/2015 07:25 pm »
There are lasers to induce lightning. No rocket needed.

Offline Jim

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #343 on: 04/30/2015 11:48 pm »

Clearly a concern, but not a show-stopper.  Any induced strikes are much further away than the existing lightning protection towers, so any EMP and induced voltages should be much less than the rocket already has to withstand.


Just hand wave it away.  Should have expected that was going to be the response. 
You are completely correct.  A handwaving response is far too serious a reply to a one-sentence, arm-waving, unsubstantiated assertion of a problem, but it's perfectly normal for NSF.
Quote
A.  Not true.  The towers are not 100% insurance. 
True, but from google maps it looks like the towers are about 150 meters from the pad.  Here we are talking at least a kilometer away, a factor of 6 further.   Any effects will be reduced by at least this factor, and more like a factor of 36 for radiated effects.

In terms of experience rather than analysis, do you know of any cases where a strike at least a kilometer away caused damage to a spacecraft due to induced voltage/EMP?

Quote
b.  And they are not going to install sensors on the spacecraft
Agreed.  The sensors would go on the pad, to measure how the rocket/payload might be affected.  If the disturbance, as measured at the rocket, is within the design specs, it should be safe to proceed.

What "hand waving"?. It is a problem. 
 It is a topic for every mission and there is a different solution for each one.  It's funny that you think that you can find the solutions and not the people working the launches.  Seems to be a recurring theme. 



Pad sensors do no good.  Satellites don't have design specs.  The potential damage is unquantifable. 

There has been damage in the past from near by hits
« Last Edit: 04/30/2015 11:56 pm by Jim »

Offline meekGee

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #344 on: 05/01/2015 01:00 am »
I wouldn't take it for granted that the current lightning mitigation strategy is optimal. Certainly not to the point where any suggestion is considered to be "hand-waving".

And especially since there was damage incurred from lightning using current methods.

The laser-triggered lightning idea is a lot more than a testing method.  It can actively discharge clouds.  I've heard of it before, but don't know the exact details.

Still, the pilot rocket idea better simulates the real rocket launch (but cannot be used continuously)
« Last Edit: 05/01/2015 05:33 am by meekGee »
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Offline deruch

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #345 on: 05/01/2015 06:01 am »
I wouldn't take it for granted that the current lightning mitigation strategy is optimal. Certainly not to the point where any suggestion is considered to be "hand-waving".

And especially since there was damage incurred from lightning using current methods.

The laser-triggered lightning idea is a lot more than a testing method.  It can actively discharge clouds.  I've heard of it before, but don't know the exact details.

Still, the pilot rocket idea better simulates the real rocket launch (but cannot be used continuously)

I think Jim's point is that "active remediation" is unnecessary.  Just wait/scrub and launch when there's no/less lightning danger.  Sure, triggering the lightning may reduce the risk to a launch in those conditions but at the cost of potential damage while it's still on the pad.  Better to just call it a day and try again without the risks.  If you want to argue otherwise, bring numbers.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline LouScheffer

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #346 on: 05/01/2015 12:53 pm »
I wouldn't take it for granted that the current lightning mitigation strategy is optimal. [...]

And especially since there was damage incurred from lightning using current methods.

The laser-triggered lightning idea is a lot more than a testing method.  It can actively discharge clouds.  I've heard of it before, but don't know the exact details.

Still, the pilot rocket idea better simulates the real rocket launch (but cannot be used continuously)

I think Jim's point is that "active remediation" is unnecessary.  Just wait/scrub and launch when there's no/less lightning danger.  Sure, triggering the lightning may reduce the risk to a launch in those conditions but at the cost of potential damage while it's still on the pad.  Better to just call it a day and try again without the risks.  If you want to argue otherwise, bring numbers.
But even this strategy of standing down has risks.  As Jim himself noted
A.  The towers are not 100% insurance. 
So if active triggering could keep lightning strikes further away from the pad, it might be worthwhile, even if you don't use it to try to launch in otherwise iffy circumstances.

Offline guckyfan

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #347 on: 05/01/2015 01:02 pm »
My thought was more like fire the lasers if the weather conditions are not clearcut. If they trigger lightning, then don't launch.

Online abaddon

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #348 on: 05/01/2015 02:44 pm »
Since this has nothing to do with SpaceX in particular (and we have absolutely no indication that SpaceX has any intent to do anything like this), maybe this belongs somewhere else, like Advanced Concepts?

Offline Galactic Penguin SST

Re: General Falcon and Dragon discussion (Thread 12)
« Reply #349 on: 05/02/2015 05:54 pm »
One question that I never got an answer: since according to Jim Falcon 9 does not use TDRS for telemetry when flying out of ground stations, what ground stations are used in Africa for GTO and other BLEO flights from the Cape? Some of the ones also used by Ariane? (like Libreville, Gabon and Malindi, Kenya)

Or do SpaceX use TDRS after all?
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Offline deruch

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #350 on: 05/19/2015 11:55 pm »
I wouldn't take it for granted that the current lightning mitigation strategy is optimal. [...]

And especially since there was damage incurred from lightning using current methods.

The laser-triggered lightning idea is a lot more than a testing method.  It can actively discharge clouds.  I've heard of it before, but don't know the exact details.

Still, the pilot rocket idea better simulates the real rocket launch (but cannot be used continuously)

I think Jim's point is that "active remediation" is unnecessary.  Just wait/scrub and launch when there's no/less lightning danger.  Sure, triggering the lightning may reduce the risk to a launch in those conditions but at the cost of potential damage while it's still on the pad.  Better to just call it a day and try again without the risks.  If you want to argue otherwise, bring numbers.
But even this strategy of standing down has risks.  As Jim himself noted
A.  The towers are not 100% insurance. 
So if active triggering could keep lightning strikes further away from the pad, it might be worthwhile, even if you don't use it to try to launch in otherwise iffy circumstances.

http://www.pbs.org/wnet/savageplanet/03deadlyskies/02lresearch/indexmid.html
Quote
Another alternative is to induce lightning from passing thunderclouds. The most effective technique for triggering lightning involves launching a small rocket trailing a thin grounded wire toward a charged cloud overhead. The rockets used at Camp Blanding are about three feet long, and are fitted with a special spool carrying Kevlar-reinforced copper wire. This wire, connected to a designated strike point on the ground, extends down as the rocket rises towards the thundercloud. "This is equivalent to erecting a tall thin structure," Dr. Rakov explains. "The wire distorts the electrical field under the cloud, and if the conditions are right, there will be a lightning discharge."

"It is a dangerous operation," says Dr. Rakov. "Sometimes lightning does not behave well. Sometimes it deflects from the path as defined by the wire, and strikes elsewhere." No one is allowed outside during the tests, and all work is conducted from a special metallic trailer that is fully grounded and designed to protect the scientists from "anomalous discharges." No metallic wires enter the trailer, only pneumatic tubes and fiber optic cables to link the scientists with their rockets and testing instruments. "Why? Because lightning can travel along metallic wires, and get to you inside the shelter."

What it looks like: https://i.imgur.com/Wq8Ayh1.gifv

Doesn't sound quite like the fail-safe it's been thought to be by some on this forum.  That said, any real discussion of it by actual operators has to be based on weighing the positive against the negative.  Which, I think, is all anyone has suggested here.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Online docmordrid

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #351 on: 05/26/2015 09:25 pm »
@Gruss_SN Mike Gruss Space News
BREAKING: The Air Force has certified SpaceX's Falcon 9 rocket to launch national security satellites.
https://twitter.com/Gruss_SN/status/603308428145074176

Offline nadreck

Re: General Falcon and Dragon discussion (Thread 12)
« Reply #352 on: 05/26/2015 09:40 pm »
@Gruss_SN Mike Gruss Space News
BREAKING: The Air Force has certified SpaceX's Falcon 9 rocket to launch national security satellites.
https://twitter.com/Gruss_SN/status/603308428145074176

Bloomberg's got it: http://www.bloomberg.com/news/articles/2015-05-26/spacex-gets-u-s-approval-to-enter-70-billion-military-market
It is all well and good to quote those things that made it past your confirmation bias that other people wrote, but this is a discussion board damnit! Let us know what you think! And why!

Online FutureSpaceTourist

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #353 on: 05/26/2015 10:29 pm »
Here's the USAF press release: http://www.af.mil/News/ArticleDisplay/tabid/223/Article/589724/air-forces-space-and-missiles-system-center-certifies-spacex-for-national-secur.aspx

Quote
Air Force's Space and Missiles System Center Certifies SpaceX for National Security Space Missions

By Secretary of the Air Force Public Affairs, / Published May 26, 2015

LOS ANGELES AIR FORCE BASE, El Segundo, Calif. (AFNS) -- Lieutenant General Samuel Greaves, Commander of the Air Force Space and Missile Systems Center (SMC) and Air Force Program Executive Officer for Space, has announced the certification of Space Exploration Technologies Corporation’s (SpaceX) Falcon 9 Launch System for national security space missions.

SpaceX is now eligible for award of qualified national security space launch missions as one of two currently certified launch providers. The first upcoming opportunity for SpaceX to compete to provide launch services is projected to be in June when the Air Force releases a Request for Proposal for GPS III launch services.

“This is a very important milestone for the Air Force and the Department of Defense,” said Secretary of the Air Force Deborah Lee James. “SpaceX’s emergence as a viable commercial launch provider provides the opportunity to compete launch services for the first time in almost a decade. Ultimately, leveraging of the commercial space market drives down cost to the American taxpayer and improves our military’s resiliency.”

This milestone is the culmination of a significant two-year effort on the part of the Air Force and SpaceX to execute the certification process and reintroduce competition into the Evolved Expendable Launch Vehicle (EELV) program. The Air Force invested more than $60 million and 150 people in the certification effort which encompassed 125 certification criteria, including more than 2,800 discreet tasks, 3 certification flight demonstrations, verifying 160 payload interface requirements, 21 major subsystem reviews and 700 audits in order to establish the technical baseline from which the Air Force will make future flight worthiness determinations for launch.

“The SpaceX and SMC teams have worked hard to achieve certification, said Greaves. “And we’re also maintaining our spaceflight worthiness process supporting the National Security Space missions. Our intent is to promote the viability of multiple EELV-class launch providers as soon as feasible.”

Elon Musk, SpaceX CEO and Lead Designer, stated, “This is an important step toward bringing competition to National Security Space launch. We thank the Air Force for its confidence in us and look forward to serving it well.”

The certification process provides a path for launch-service providers to demonstrate the capability to design, produce, qualify, and deliver a new launch system and provide the mission assurance support required to deliver national security space satellites to orbit. This gives the Air Force confidence that the national security satellites being delivered to orbit will safely achieve the intended orbits with full mission capability.

The SMC, located at Los Angeles Air Force Base, Calif., is the U.S. Air Force's center for acquiring and developing military space systems. Its portfolio includes GPS, military satellite communications, defense meteorological satellites, space launch and range systems, satellite control networks, space based infrared systems and space situational awareness capabilities.


Offline GalacticIntruder

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #355 on: 06/04/2015 04:21 am »
http://www.issconference.org/#papers

Musk chat. July 7, 2015 at 08:45-10:00 am ET.

No idea what he will talk about. No idea who the interviewer is. However, I see Rachel Crane will be there, so it could be her, which would not be surprising.

Hopefully we get something new. We know about his past and his goals. And I don't want to hear about what he thinks about Vance's Musk Biography.

It would be a great time to show off the long awaited SpaceX spacesuit, even some Dragon 2 stuff.
« Last Edit: 06/04/2015 07:17 am by GalacticIntruder »
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Offline DJPledger

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #356 on: 06/04/2015 06:59 am »
http://www.issconference.org/#papers

Musk chat. July 7, 2015 at 08:45-10:00 ET.

No idea what he will talk about. No idea who the interviewer is. However, I see Rachel Crane will be there, so it could be her, which would not be surprising.

Hopefully we get something new. We know about his past and his goals. And I don't won't to hear about what he thinks about Vance's Musk Biography.

It would be a great time to show off the long awaited SpaceX spacesuit, even some Dragon 2 stuff.
Lets also hope he will give us some new info. on the Raptor as well.

Offline okan170

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #357 on: 06/09/2015 12:08 am »
Dragon 2 approaching the space station, her first port of call.

Online Paul_G

Re: General Falcon and Dragon discussion (Thread 12)
« Reply #358 on: 06/09/2015 12:09 pm »
Okan,

Great image :) Can I ask what the white inflatable(? ) structure is on top of the Dragon capsule?

Thanks

Paul

Online Jimmy Murdok

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Re: General Falcon and Dragon discussion (Thread 12)
« Reply #359 on: 06/09/2015 12:19 pm »
Okan,

Great image :) Can I ask what the white inflatable(? ) structure is on top of the Dragon capsule?

Thanks

Paul
No inflatable, just the shiny nose co

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