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.
Quote from: LouScheffer on 04/30/2015 11:40 amClearly 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
Quote from: Jim on 04/30/2015 01:35 pmQuote from: LouScheffer on 04/30/2015 11:40 amClearly 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.QuoteA. 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?Quoteb. And they are not going to install sensors on the spacecraftAgreed. 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.
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)
Quote from: meekGee on 05/01/2015 01:00 amI 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.
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)
A. The towers are not 100% insurance.
Quote from: deruch on 05/01/2015 06:01 amQuote from: meekGee on 05/01/2015 01:00 amI 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 Quote from: Jim on 04/30/2015 01:35 pmA. 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.
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."
@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
Air Force's Space and Missiles System Center Certifies SpaceX for National Security Space MissionsBy Secretary of the Air Force Public Affairs, / Published May 26, 2015LOS 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.
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
http://www.issconference.org/#papersMusk 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.
Okan,Great image Can I ask what the white inflatable(? ) structure is on top of the Dragon capsule?ThanksPaul