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Groups > sci.space.policy > #56043
| Newsgroups | sci.space.policy |
|---|---|
| Date | 2016-04-12 15:16 -0700 |
| References | (4 earlier) <MPG.316ffb6f5d1870c49899a6@news.eternal-september.org> <d16f47ee-6c0b-4f96-b064-09651ae3fe4d@googlegroups.com> <MPG.317330a540afbcab9899b4@news.eternal-september.org> <5789fe7d-2d7f-48b1-b2d0-605896b4af66@googlegroups.com> <MPG.317439ab50a2a8c99899b8@news.eternal-september.org> |
| Message-ID | <3df4f3cc-95bf-48bd-9ae5-c658c63b311e@googlegroups.com> (permalink) |
| Subject | Re: Successful flight by Blue Origin |
| From | William Mook <mokmedical@gmail.com> |
On Monday, April 11, 2016 at 3:22:06 AM UTC+12, Jeff Findley wrote: > In article <5789fe7d-2d7f-48b1-b2d0-605896b4af66@googlegroups.com>, > mokmedical@gmail.com says... > > > > On Sunday, April 10, 2016 at 8:31:25 AM UTC+12, Jeff Findley wrote: > > > In article <d16f47ee-6c0b-4f96-b064-09651ae3fe4d@googlegroups.com>, > > > mokmedical@gmail.com says... > > > > > All of that added complexity and added mass would cost money compared to > > > > > using "leftover" fuel and oxidizer and an engine that is already there > > > > > for launch. > > > > > > > > The complexity from an operational point of view is nil. > > > > > > That is absolute bullshit. > > > > No its not. > > It is clear you do not understand complexity as it applies to systems > engineering. Its clear you favour personal attacks rather than keeping to the issue because you have no real understanding of the issues. Look at what you've said previously and think about it for a minute. There's a reason the fuel is 'left over' - in a nearly empty tank. Start trying to understand the foolish things you say, and then we might have a conversation that is more than just pointless name calling. > > > > Added engines, tanks, plumbing, and etc. *is* adding complexity to the > > > design. Costs scale with complexity. > > > > You are favouring ill conceived generic statements about products which have provable flight statistics. > > You are engaging in hand-waving. No, I'm pointing out that general rules of thumb are not favoured when you have provable flight statistics and engineering data to go with. Interesting that you call such thing hand-waving especially after you wrongly asserted I know nothing about how to use those statistics in analysing complex systems while you are the one ignoring them, favouring name calling instead. > You need the Merlin engine(s) and fuel > to perform first the burn to bleed off horizontal velocity and then to > reduce the speed during reentry. I think you're confabulating what was done as part of the development program and what must be done for rapid turn around ultimately. In September 2013, SpaceX successfully relit three engines of a spent booster on an orbital launch, and the booster re-entered the atmosphere at hypersonic speed without burning up. With the data collected from the first flight test of a booster-controlled descent from high altitude, coupled with the technological advancements made on the Grasshopper low-altitude landing demonstrator, SpaceX announced it believed it was ready to test a full land-recovery of a booster stage at that time. Based on the positive results from the first high-altitude flight test, SpaceX advanced the expected date of a test from mid-2014 to early 2015, with the intention of doing so on the next Space Station cargo resupply flight. That flight took place on April 18, 2014. The SpaceX reusable launch system development program is entirely privately funded organised to develop a set of new technologies for an orbital launch system that is reused many times in a manner similar to aircraft. SpaceX is developing the technologies over a number of years to provide full and rapid reusability of space launch vehicles. The project's long-term objectives include 1) returning a launch vehicle first stage to the launch site in minutes and 2) to return a second stage to the launch pad following orbital realignment with the launch site and atmospheric reentry in less than 24 hours. SpaceX's long term goal is that both stages of their orbital launch vehicle will be designed to allow reuse a few hours after return. > Adding a landing burn to this adds > zero additional hardware to the system and has been proven to work (once > on land and once on a barge). If you look at the technical reports related to integrating the Grasshopper experience with the booster experience you will see that you are dead wrong in your assertion that zero hardware was added. There are several major problems; (1) sucking propellant efficiently from a nearly empty tank that's being shaken violent is hard, (2) throttling a booster engine down so that it can fly empty is hard, (3) controlling an engine thrust efficiently at 2% levels is hard, They all have solutions, however, their solutions may be compared to other more direct approaches such as taking a flight ready article already in SpaceX inventory, and adapting it as a supremely reliable 'recovery pod'. Development may even be paid for by offering services to adapt other boosters for full recovery. This is also good PR for SpaceX. > > > > Especially since we're talking > > > about *toxic* hypergolic propellants > > > > SuperDraco engines utilize a storable propellant mixture of > > monomethylhydrazine fuel and dinitrogen tetroxide oxidizer. They > > are capable of being restarted many times, and have the capability > > to deeply reduce their thrust providing precise control during > > propulsive landing. > > True, but they're also toxic as hell. So's LOX and RP-1 and methane. Read the MSDS on them. Its a truism. Rocket fuels are dangerous. Who knew? The key is understanding the danger and designing systems that work regardless of the dangers. > This introduces all sorts of > added processing costs (and time) both before launch and after landing. The difference is nil. > You're ignoring that completely. No I'm not. In its F9R configuration, the launcher has all characteristics of the Falcon 9 v1.1 with the addition of 1) four landing legs, 2) an attitude control system and 3) four grid fins to the first stage 4) massive changes to the tank internals to make use of the last dregs of propellant, 5) massive changes to the Merlin internals to efficiently produce low levels of throttable thrust, Plugging in four flight ready modules adapted from hardware already flying on the Dragon V2, and plugging those modules into the landing legs, and ditching 4 & 5 above, actually improves performance, and reduces risks, if you trouble yourself to look at real data. > > > to a stage which has been proven to > > > not need them. > > > > Four self contained modular systems based on those developed for > > the Dragon V2 capsule, each massing 1500 kg and carrying 1388 kg > > of propellant - built into a module and each attached to the > > landing strut, reduces complexity and weight of the booster to > > which it is attached, and given the statistics of NTO/MMH > > hypergolic engines to date, improves reliability. > > Possibly, No, certainly! Again, if you trouble yourself to actually look at the relevant data, you will see the path I have described has much to recommend it. > but with increased complexity and added processing costs that > you completely ignore. The maintenance on the modified tanks and Merlin engine, the logistics of the reaction control system, already add the compleixities you speak of and more. Using more efficient Merlin engine and lighter tanks during ascent, and burning ALL the propellant during ascent, more than makes up for the changes I'm speaking of. The ability to make a modular system of engines and avionics that can be adapted to any number of boosters, and flight systems, is a further plus. Adapting the engines to use other propellant combinations, and reserving MMH/NTO as a 'spark plug' to restart engines, is another plus. The major reason Musk purchased TRWs assets was the pintle fed engine patents. These may be efficiently adapted to any propellant combination. SpaceX has already announced that it will create a LOX/LNG version of their Merlin. So, starting with an off-the-shelf flight proven propellant combination doesn't mean they're permanently wed to that combination. > > > And toxicity is just one of the reasons that processing > > > costs go *up* for a vehicle which uses hypergolics. > > > > Hypergolic fuels have well defined material safety and data > > regarding their routine use. > > Of course they're well defined. So, they're not an unknown or unreasonable risk. The risks are known and can be assessed. When you do that you find you are over-stating the risks for theatrical effect. > They're so well defined that NASA > studied replacing toxic hypergolics on the shuttle due to the added > cost, schedule, and safety hazards they introduce. That's a fact you > ignore. You are familiar with the old Soviet era joke. USSR has invaded the Sahara, they've discovered a shortage of sand. Same here. Fact is, hypergolic fuels are ALREADY being flown in SpaceX boosters and payloads. The risks and safety issues are not the problem you claim, and given the existing reaction control system on the SpaceX F9R, the addition of eight super draco engines in four module, attached to the landing gear struts, are not a real challenge. You overstate the dangers because you are not familiar with them. Furthermore, you also ignore the ongoing program at SpaceX to redue the toxicity of hypergolics by using new chemistries like DMAZ, and SpaceX's ability to transition to other fuels entirely once the core system is worked out at low risk, and this migration path can be done at low risk as well. DMAZ - low risk hypergolics (2004) http://adsabs.harvard.edu/full/2004ESASP.557E..22M > > > > LOX and kerosene are both super cheap and are relatively non-toxic > > > compared to hypergolics. > > > > While exposure risk to MMH and NTO vapours is greater than that of > > LOX and kerosene, you seem to ignore that in combination LOX > > Kerosene can be quite deadly in certain circumstances, forming > > explosive solids that are easily detonated. Spilled kerosene have > > caused significant fires in actual use, and have consequently been > > responsible for more deaths in rocket operations throughout history. > > So, in light of this actual experience, your attempts to denigrate > > MMH and NTO, which already being used by SpaceX on their MANNED > > CAPSULE, it rather foolish. > > You *need* the LOX and kerosene during launch *anyway*, so using the > excess for landing does *not* add any complexity to launch operations. Buy a litre of your favourite beverage. Now drink the bottle dry. Look inside, there's a few percent left. Now, drink that. See how easy it is. It isn't. Now before you try to drink the last drops of your beverage from the bottle, make sure you keep shaking it violently as you do so. You will then get some small measure of the difficulty of making use of the propellant the way you describe. Now, there are work arounds. You can have a pipeline with a large cavity in it that the propellant drains thropugh to keep your engine going when the main tank is empty. You can load your tank up with lots more propellant than you need, to be sure to get the little you need when its near empty. These work arounds are costly and complex and wasteful. Now, start your car engine and open the hood. Set the idle mixture adjustment screws so that your engine produces about 2% of the speed recommended for idle. Keep adjusting the air and fuel ratios so that you get the idle rate well below the recommended idle speed. Now try to drive your car. You can't. There is a risk it will stop working. It will also be very wasteful of fuel. This is similar to what we're asking the Merlin to do when it is coming in for a landing. And if its hard to start, or cuts out at the wrong time, during vertical descent, we're in trouble. So, there are changes made to the engine to allow it to operate reliably and efficiently in this mode. These engine and tank changes have their own risks costs weights and maintenance issues. Elimination of this requirement is a plus in overall design. Against this we look at the costs and weights of the solution I've proposed. When you use actual data, you can see that this is a perfectly legitimate path to take. > As for landing operations, if you don't use the remaining LOX and > kerosene for landing, you're still going to have to deal with it post- > landing. You fail to ask why do you have suprlus LOX and Kerosene? The answer is because you need it to fly the system the way you describe at some measure of assured performance. If you don't try to over load the tanks to assure yourself a relatively risk free relight under very trying conditions, then you can burn that LOX Kerosene before MECO where it does the most good to deliver payload to orbit, and then use your separate highly reliable system to land the booster. > > Adding toxic hypergolics *does* add additional "safing" and handling > complexities post landing. It adds known complexities performance costs and dangers. When weighed against the known complexities performance costs and dangers of making use of ullage propellant for landing, the approach I've described is a workable alternative that gives SpaceX a product to sell into the market besides. > > > > They're already building super dracos and flying them to land > > > > capsules. A self contained module plugged into the landing > > > > struts and tied to the avionics of a booster would be child's > > > > play and easily adapted to any stage. This would let the > > > > booster engines be optimised for their mission and let ALL > > > > the propellant be used as well. > > > > > > And would drive up the costs of the first stage versus carrying along > > > extra LOX and kerosene. > > > > No it wouldn't. Because a more precise and controlled application > > of thrust reduces total delta vee requirements to a minimum during > > recovery. Furthermore, deeply throttable main booster engines have > > greater fire and explosion risks, and are not so precisely > > controlled. Further, operating at reduced thrust at sea level, > > causes design choices to be made that alter the efficiency of the > > engine reducing its efficiency relative to a pure boost engine. > > Finally, containing a small quantity of landing propellant in a > > separate container improves fuel utilisation efficiency when > > compared to taking the remnants from a larger tank that is > > undergoing maneuvers and is shaking. > > You're quite wrong. Nonsense. You've already admitted there's lots of LOX and Kerosene to be dealt with post landing. I've explained why such massive quantities of propellant are needed when draining propellant from a nearly empty tank. Its best to optimise the Merlin engine for boost, and make use of ALL propellant during boost phase, and have specialty recovery modules for recovery phase. I've even pointed out that ditching the landing gear and recovery propulsion altogether and creating a flying recovery platform, is the most efficient approach, but should be approached in slow stages. > Adding complexity (especially toxic hypergolics) > adds costs. The costs are under $100,000 and the cost of a Falcon is $61 million. The modified Merlin and F9R tanking costs about $2.2 million according to the reports I've seen. Eight super Draco engines with propellant tanks is $1.6 million. The cost of MMH/NTO products for industrial use is $2 per kg. The cost when used in rocket applications is $17 per kg following all the safety rules imposed by regulators. Now, NASA has reported $170 per kg cost, but SpaceX experience is nowhere near that. Even allowing $20 per kg 1800 kg is $36,000 per launch on a $61 million value created per launch. Now, the chance of a losing a $61 million booster is 1 in 100 using the throttled back engine - so the cost per use could reasonably be put at $610,000 per event. The chance of losing the same booster is 1 in 150 using the modular approach so the cost is $460,000 per event. This more than pays for the fuel costs. Also, if we gain 3% in payload from burning LOX/RP1 before MECO we produce more 3% more value per launch. 3% of $61 million is $1.83 million. Finally, if we have less maintenance cost on a simpler engine and tank design using a modular system as I've described, then we have even further savings per launch. > Jeff > -- > All opinions posted by me on Usenet News are mine, and mine alone. > These posts do not reflect the opinions of my family, friends, > employer, or any organization that I am a member of. Real analysis using real data based on real experience indicates that the alternative path I've outlined is a realistic one. If SpaceX doesn't have the people or capital to pursue it yet, then its an opportunity others may pursue, or pursue in partnership with SpaceX.
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Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2015-11-24 18:10 -0500
Re: Successful flight by Blue Origin "Greg \(Strider\) Moore" <mooregr@deletethisgreenms.com> - 2015-11-24 19:38 -0500
Re: Successful flight by Blue Origin JF Mezei <jfmezei.spamnot@vaxination.ca> - 2015-11-24 20:15 -0500
Re: Successful flight by Blue Origin Alain Fournier <alain245@videotron.ca> - 2015-11-24 21:01 -0500
Re: Successful flight by Blue Origin David Spain <nospam@127.0.0.1> - 2015-11-27 08:07 -0500
Re: Successful flight by Blue Origin JF Mezei <jfmezei.spamnot@vaxination.ca> - 2015-11-24 19:59 -0500
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2015-11-25 09:50 -0500
Re: Successful flight by Blue Origin Dr J R Stockton <reply1500@merlyn.demon.co.uk.invalid> - 2015-11-26 22:28 +0000
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2015-11-27 14:14 -0500
Re: Successful flight by Blue Origin JF Mezei <jfmezei.spamnot@vaxination.ca> - 2015-11-28 00:31 -0500
Re: Successful flight by Blue Origin David Spain <david.l.spain@gmail.com> - 2015-11-30 11:17 -0800
Re: Successful flight by Blue Origin JF Mezei <jfmezei.spamnot@vaxination.ca> - 2015-11-30 17:24 -0500
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2015-12-01 05:53 -0500
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2015-11-27 14:10 -0500
Re: Successful flight by Blue Origin "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2015-12-05 08:41 -0500
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2015-12-05 10:14 -0500
Re: Successful flight by Blue Origin "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2016-04-05 21:49 -0400
Re: Successful flight by Blue Origin Thomas Koenig <tkoenig@netcologne.de> - 2016-04-06 21:30 +0000
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-07 06:07 -0400
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-07 12:45 -0700
Re: Successful flight by Blue Origin Thomas Womack <twomack@chiark.greenend.org.uk> - 2016-04-08 16:41 +0100
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-08 18:27 -0400
Re: Successful flight by Blue Origin Rick Jones <rick.jones2@hpe.com> - 2016-04-07 17:43 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-08 12:56 -0700
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-08 18:26 -0400
Re: Successful flight by Blue Origin "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2016-04-10 08:40 -0400
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-11 06:11 -0400
Re: Successful flight by Blue Origin "Greg \(Strider\) Moore" <mooregr@deletethisgreenms.com> - 2016-04-11 06:37 -0400
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-08 23:13 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-08 22:01 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-09 06:27 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-09 08:08 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-09 19:03 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-09 13:20 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-09 21:17 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-09 20:22 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-10 06:11 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-10 06:43 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-10 17:09 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-10 17:39 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-11 19:13 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-11 19:59 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-12 06:10 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-12 07:12 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-12 18:25 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-12 15:36 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-12 23:19 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-12 22:23 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-13 18:18 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-13 13:06 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-13 20:44 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-13 19:24 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-14 04:29 +0000
Re: Successful flight by Blue Origin Greg Goss <gossg@gossg.org> - 2016-04-14 01:06 -0600
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-14 18:22 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-14 00:56 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-14 18:28 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-14 14:42 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-14 22:35 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-14 17:22 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-15 00:47 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-14 19:30 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-15 21:45 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-15 16:09 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-16 00:02 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-16 02:59 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-16 17:03 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-16 11:28 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-16 19:17 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-16 12:52 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-16 20:50 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-16 19:40 -0700
Re: Successful flight by Blue Origin jimp@specsol.spam.sux.com - 2016-04-17 05:24 +0000
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-16 23:59 -0700
Re: Successful flight by Blue Origin William Mook <mokmedical@gmail.com> - 2016-04-09 10:29 -0700
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-09 16:31 -0400
Re: Successful flight by Blue Origin William Mook <mokmedical@gmail.com> - 2016-04-09 18:33 -0700
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-10 11:22 -0400
Re: Successful flight by Blue Origin William Mook <mokmedical@gmail.com> - 2016-04-12 15:16 -0700
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-12 21:47 -0400
Re: Successful flight by Blue Origin William Mook <mokmedical@gmail.com> - 2016-04-12 19:18 -0700
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-13 06:27 -0400
Re: Successful flight by Blue Origin William Mook <mokmedical@gmail.com> - 2016-04-13 18:35 -0700
Re: Successful flight by Blue Origin nj_kruse@me.com (Niels Jørgen Kruse) - 2016-04-13 09:48 +0200
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-13 06:28 -0400
Re: Successful flight by Blue Origin William Mook <mokmedical@gmail.com> - 2016-04-13 18:36 -0700
Re: Successful flight by Blue Origin Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-04-14 22:50 -0400
Re: Successful flight by Blue Origin William Mook <mokmedical@gmail.com> - 2016-04-14 22:09 -0700
Re: Successful flight by Blue Origin Fred J. McCall <fjmccall@gmail.com> - 2016-04-12 21:39 -0700
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