Quote from: QuantumG on 12/03/2015 04:35 amQuote from: sdsds on 12/03/2015 04:29 amLet me ask this, though, related to current events at XCOR: if Koenigsmann (or some crew saftey expert employee you admire) walked away from SpaceX to "pursue other opportunities", and all you had was Musk's assurance that no corners were being cut, would you still be just as happy to get on board a Dragon?You're asking the wrong guy.. I've gotten on the back of a friend's homebuilt gyrocopter, and I know he sucks at welding.What no gopro video?
Quote from: sdsds on 12/03/2015 04:29 amLet me ask this, though, related to current events at XCOR: if Koenigsmann (or some crew saftey expert employee you admire) walked away from SpaceX to "pursue other opportunities", and all you had was Musk's assurance that no corners were being cut, would you still be just as happy to get on board a Dragon?You're asking the wrong guy.. I've gotten on the back of a friend's homebuilt gyrocopter, and I know he sucks at welding.
Let me ask this, though, related to current events at XCOR: if Koenigsmann (or some crew saftey expert employee you admire) walked away from SpaceX to "pursue other opportunities", and all you had was Musk's assurance that no corners were being cut, would you still be just as happy to get on board a Dragon?
Quote from: Lars-J on 12/02/2015 07:13 amQuote from: sdsds on 12/02/2015 06:49 amOn the safety question, though: I would climb aboard a rocket blessed by St. Greason with much less hesitation than one blessed by Saint Musk or Saint Bezos. Greason just seems to know those issues a heck of a lot better....But this I just don't get... Why? Because Greason made some very insightful comments during the Augustine committee? What has he actually developed that has been a successful aerospace product? Where does this belief in his ability to A) get things done and B) make them safe come from? I really want to know.In my case, my experience with Jeff goes way back before the Augustine committee. I've been interacting with Jeff since I was 16, initially via the internet, and also in-person at various conferences and professionally while I was at Masten (XCOR helped us out quite a bit during the NGLLC). Admittedly, I probably only interacted directly with Jeff a few times per year over the past almost 20 years, so we weren't super-duper close or anything. But I've seen his approach to engineering over the years, and while I can't say I agree with every design decision they've had (for instance I'm more a fan of VTVL and automation than wings and piloted control), I trust his engineering judgement as being solid. I've heard him and his team discuss their approach to 3rd party safety, regulation, reliability, and designing for reusability and safety over performance, and even seen a lot more of the details of how they do that than most people who haven't worked there at XCOR.Had Jeff managed to get Lynx flying while he was there, I would've flown on it in a heartbeat (assuming I could've afforded the ticket). From a safety standpoint, I think where he was taking Lynx would've been a lot safer than where SS2 or Blue Shephard are likely going.That said, XCOR is no longer in Jeff's hands. Personally, from what I'm hearing from Jay Gibson, he might yet be able to successfully drive Lynx to operational status, even minus Jeff. He definitely has more of a track-record in aerospace/aviation product development. I hope that he can maintain their focus on safety, operability, and reusability while doing so. Even without Jeff at the helm anymore, I'd still probably feel safer in Lynx than SS2, and probably just as safe as I would in Blue Shephard or Dragon V2, in spite of well over an order of magnitude more resources being thrown at the latter two developments.~Jon
Quote from: sdsds on 12/02/2015 06:49 amOn the safety question, though: I would climb aboard a rocket blessed by St. Greason with much less hesitation than one blessed by Saint Musk or Saint Bezos. Greason just seems to know those issues a heck of a lot better....But this I just don't get... Why? Because Greason made some very insightful comments during the Augustine committee? What has he actually developed that has been a successful aerospace product? Where does this belief in his ability to A) get things done and B) make them safe come from? I really want to know.
On the safety question, though: I would climb aboard a rocket blessed by St. Greason with much less hesitation than one blessed by Saint Musk or Saint Bezos. Greason just seems to know those issues a heck of a lot better....
XCOR has a press release on their closed loop engine cycle: http://xcor.com/news/xcor-engineers-announce-major-breakthrough-in-engine-technology
There's still some work to do to improve the cycle efficiency before this engine, that in its basic 'open cycle' form has already had hundreds of successful test firings, is ready for flight
Quote from: Gliderflyer on 12/14/2015 03:38 pmXCOR has a press release on their closed loop engine cycle: http://xcor.com/news/xcor-engineers-announce-major-breakthrough-in-engine-technologyA question for the rocket propulsion folks among us.I can't make out exactly what is going on here. Is this an improvement on traditional rocket engine cycles? I don't see that they've provided a descriptor, a name for this technology or feature. How does it, whatever "it" is, compare with how rocket engines have handled this in the past?
Quote from: Llian Rhydderch on 12/17/2015 05:18 pmQuote from: Gliderflyer on 12/14/2015 03:38 pmXCOR has a press release on their closed loop engine cycle: http://xcor.com/news/xcor-engineers-announce-major-breakthrough-in-engine-technologyA question for the rocket propulsion folks among us.I can't make out exactly what is going on here. Is this an improvement on traditional rocket engine cycles? I don't see that they've provided a descriptor, a name for this technology or feature. How does it, whatever "it" is, compare with how rocket engines have handled this in the past?They haven't really disclosed anything about their technology. What we do know is that their pump is powered by pistons rather than a turbine. And that they have make it work in open cycle. What this means, at least if they are, in fact, using the industry's nomenclature, is that they gases used to drive the pistons was dumped to the atmosphere."Closing the cycle" should mean that they somehow recover the fluids used to drive the pistons and either they inject them on the combustion chamber or they recover them somehow.I've seen an article here saying they use an expander cycle. So I would assume that they pistons are driven by expanding LOX. But, they might use a different fluid, that expands by way of cooling the MCC and then pass it through a heat exchanger with the LOX line to compress it again. This might require subcooled LOX. But this is all pure speculations on my part.Now, if you look at the US 7,784,268 B1 (PDF) patent, you will see that they run the LOX through the expander cycle and then after it goes through the turbine, where it cools down enough that is liquid again. Thus, it can go either to the LOX tank or the pump inlet. That would be a closed cycle engine.They use pumps instead of turbines. But expanding the gas should mean that it adiabatically cools. So they may be have found a way to make this work (probably on the supercritical state) with pumps.I'm not saying that the 5K18 engine works exactly like that, but the application was 2006 and the press release states that they have been working on this cycle since 2006. So, at least it is an educated guess.
At the OrbitOz presentation last night given by International Space University (ISU) President Professor Walter Peeters he said that XCOR had greater than 175 bookings. This information is from contacts he has within the industry.
over 350 clients are as eager as we are to undertake the first trip into space
I'd play this video game.
