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Artemis 3 Mission in 2024
On 7/26/2019 7:37 AM, Jeff Findley wrote:
Plus such an approach nicely dovetails with building earth orbiting space stations and the like. The actual Space Race was short and sweet and sent us down the dead end of large expendable launch vehicles. Unfortunately, NASA has gone down that same dead end yet again with Ares/SLS. It's simply not sustainable. I write this on the morning after Starhopper made its first successful hop. This was the first flight of a full flow staged combustion liquid fueled rocket engine. That is a sustainable, reusable, approach to spaceflight. I'm glad SpaceX is pursuing this, because NASA dropped the ball long ago on reusabilty. Jeff Yes, this was great news. I'm still trying to find a decent video of the event, but it's early. I haven't had my coffee yet. Jeff I couldn't agree more with all your points. Expendables are exactly that and a dead end. Elon Musk has a great analogy to that. Imagine air travel involved a parachute that you use to jump out of the airplane over your destination while the aircraft continues to fly out over an uninhabited area, runs out of fuel and crashes either into the desert or the ocean. That's what we have for a space program today with expendables in Orion/SLS. We need to expend that paradigm. Dave |
#12
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Artemis 3 Mission in 2024
On 19-07-26 15:00 , David Spain wrote:
On 7/26/2019 7:37 AM, Jeff Findley wrote: ... I write this on the morning after Starhopper made its first successful hop. ... Yes, this was great news. I'm still trying to find a decent video of the event, but it's early. I haven't had my coffee yet. The on-board engine view is nice, one can see the ground falling away... https://www.youtube.com/watch?v=eaBMqs1z9cc -- Niklas Holsti Tidorum Ltd niklas holsti tidorum fi . @ . |
#13
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Artemis 3 Mission in 2024
On 7/26/2019 9:19 AM, Niklas Holsti wrote:
On 19-07-26 15:00 , David Spain wrote: On 7/26/2019 7:37 AM, Jeff Findley wrote: Â*Â* ... I write this on the morning after Starhopper made its first successful hop. Â*Â* ... Yes, this was great news. I'm still trying to find a decent video of the event, but it's early. I haven't had my coffee yet. The on-board engine view is nice, one can see the ground falling away... https://www.youtube.com/watch?v=eaBMqs1z9cc Nice, you can see the shock diamond form as the raptor throttles up. Thanks for the link. Dave |
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Artemis 3 Mission in 2024
In article , says...
On 7/26/2019 2:27 AM, William Elliot wrote: If weren't for thea Russian Sputnik, would US have a space program? An interesting question. I would say, yes, but it would have looked very differently from what we remember and it would have been primarily a US Air Force program working in conjunction with the NACA. Sputnik was inevitable, but the *real* story is that Von Braun's team was ready to add a small 3rd kick stage to the Jupiter C rocket a year or so *before* Sputnik, that would have put a satellite into orbit, but Eisenhower nixed the idea. Why I'll never know. Had that been done, likely no panic, no NASA and no moon program. snip One theory is that we didn't want to be accused of overflying other countries. When Sputnik went first, from what I understand the US didn't protest the overflight. This set the stage for orbital spy satellites and the like. 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. |
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Artemis 3 Mission in 2024
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#17
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Artemis 3 Mission in 2024
"JF Mezei" wrote in message ...
What sort of different features are needed for a Moon EVA suit vs Shuttle/Station EVA suit? Bigger boots is obvious. I take it an extra layer for radiation shielding? What else? No, no extra layer. Not really feasible. But better flexibility. The current EVA suits don't bend well at the waist, nor do they need to. The A7LB used for the final Apollo missions had extra joints at the waist and neck to allow enough flexibility to sit in the lunar rover. Because of the hard torso design of the current EMU suits, they'd wouldn't be very practical on the lunar surface. Also, I believe the current suits have no buddy system connectors. I don't know about thermal considerations, but my guess is those would need to change also. for trying to prod NASA into actually doing something, but no bucks, no Buck Rogers. They'll never get the "blank check" style funding needed to do this program in that short amount of time. Political stunt. Announce great but unrealistic mission to force the next administration to be the bearer of bad news when they cancel it. -- Greg D. Moore http://greenmountainsoftware.wordpress.com/ CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net IT Disaster Response - https://www.amazon.com/Disaster-Resp...dp/1484221834/ |
#18
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Artemis 3 Mission in 2024
In article ,
says... On 2019-07-25 06:43, Jeff Findley wrote: Zero chance. This program is a burning dumpster. Won't SLS/Orion at the very least do a spin around the moon and back to Earth? It can get to a NRHO around the moon. That's why that particular orbit was chosen for Gateway. There is lots of info about this online. Options for Staging Orbits in Cis-Lunar Space - NTRS - NASA https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf Orion doesn't have the delta-V to get into a low lunar orbit and get back to earth with the margins that NASA requires. This is doubly true of some kind of other payload is co-mainifested with Orion on SLS. Note that making SLS bigger (e.g. Block 2) does not help with this problem. In fact, it makes it worse because any co-manifested payload would necessarily be bigger, to take advantage of the extra payload capacity of SLS Block 2. That's why Gateway is tuck in NRHO, not something more useful like a low polar orbit (well, close to polar, see the reference above). Casnada signed up to help with Gateway. Curious to see what went on behind the scenes for this. Our transport Minister if Marc Garneau, former astronaut who flew on Shuttle. So he would have a pretty good idea of the odds of this project. Of course Gateway will get a robotic arm, because "that's the way we've always done things with the shuttle and ISS". And of course Canada will want some of its astronauts to participate if there is a chance that they may walk on the moon. On top of that, NASA has no lunar EVA suits. Shirley than can ask Hollywood they can make these suits pretty quickly, just don't check the box that says "integrated light to make astronaut's face visible" :-) Since the last Moon rated suits date from the 1960s, how different would current designs be? This is the exact *same* problem you have with "dusting off the Saturn V plans and building new copies" only with a spacesuit. I'm not going to enumerate the many reasons that make it hard to "just build more Apollo EVA suits" because they're the same reasons. What sort of different features are needed for a Moon EVA suit vs Shuttle/Station EVA suit? Bigger boots is obvious. I take it an extra layer for radiation shielding? What else? For one, space shuttle era EMU suits are way to heavy for extended EVAs. They were designed to work in microgravity, after all. They traded away the lighter mass of the Apollo EVA suits for longevity and modularity (which naturally came with a much heavier mass). 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. |
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Artemis 3 Mission in 2024
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#20
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Artemis 3 Mission in 2024
"JF Mezei" wrote in message ...
On 2019-07-30 07:28, Jeff Findley wrote: All the people who made the Apollo suits are don't work anymore because they're either dead or retired. But surely the designs are available somewhere, perhaps even at the Smithsonian? Yes, but again, the skills necessary to actually MAKE them may not be available. This is especially good f they can have the documentation on the changes made to Apollo era suits during their short tenure as the explanation for those changes would provide valuable insights to prevent repeating same mistakes. Same problem you have with "duplicating" anything made more than 50 years ago. You have to certify it as a new design anyway, Never said they wouldn't. Whatever they make for Artemis is to be new and need to be tested. What I am arguing is that the Apollo era experience should be used as much as possible as it would help prevent problems and help guide the design of new suits. Mr Strider mentioned the number of joints etc. And yes, of course any new designs will try to learn lessons from previous designs. Not sure why you're expecting otherwise. And speaking to remaining astronauts and/or people who worked to design/build/maintain those suits could also provide insights. Would it be correct to state that the Apollo era suits were used only on one mission and new suits for each mission? Were they returned to earth or left in the LEM ? Considering they were custom made for each astronaut, yes they were only used once. And since they were required for re-entry, they were returned. Yes, they won't work well at all. Even if NASA chooses to modify the leg design for increased mobility, they still mass too much to be practical for anything other than a very short "flags and footprints" Lets not kid ourselves, the SLS/Orion, if it even lands on moon will be only flags/footprints mission. From a materials point of view, would building new Shuttle suits with modern materials (composite,s alloys) reduce their mass signifcantly or just marginally? What ends up weighting most on those suits? What made the Shuttle EVA suits so much heavier than Apollo ones? The hard torso. This is perhaps the fundamental difference between the Apollo A7L and A7LB suits and the shuttle EVA suits. The Apollo era suits were custom made for each astronaut (actually 3 per astronaut, 1 for use, 1 for training and 1 as a backup.) As such, they were guaranteed to fit the particular astronaut they were built for. For the shuttle era, NASA knew they'd be flying lots of different astronauts and could not afford (both in time and money) developing customer suits for each one. So they went with a hard torso (in I think 3 sizes, S, M, L) and then soft components for the arms and legs. These can be swapped out to fit the particular astronaut. Apparently an XS hard torso was considered, but there literally wasn't enough room for all components in the original design. I believe there are only about a dozen suits (and I believe some of the hard torsos originate from the 80s). So, new suits will need to be created, regardless. That said, some of the considerations that will go into a next generation EVA suit, especially for lunar EVA: Better mobility. Between the original suits (A7L) for the Apollo 11-14 missions and the updated (A7LB) for the 15-17 missions, an extra waist and neck joint were added. This added in their ability to bend and more importantly, sit I the LRV. Better durability. The original suits used a pair of zippers to seal them up. Easy to operate, but apparently, by the 3rd EVAs on the later missions, the components were starting to wear and air leakage was noticeable. One design consideration would be to use "suit locks" where the suit itself is basically attached to an airlock. The astronaut climbs into the back of the suit (much like the current Russian design) and closes the backpack over the opening and then the suit (with astronaut) detaches from its own personal airlock. This keeps lunar dust from entering the vehicle and simplifies cleaning and the like. But is a more complex design and I'm not sure NASA is ready to go for that complexity. And even if they do, the astronauts would still need a pressure suit for other portions of the flight. NASA is not going to let them do operations like landing, takeoff, or docking without a pressure suit. Ideally (but unlikely) higher operating pressure. The time currently used to reduce the pressure of the airlock so astronauts can go on EVA is 6-8 hours. This reduces available science time which is critical on the Moon. More likely on earlier flights NASA will simply run the entire complex at a lower pressure than ISS. Fit 90% of all astronauts like current shuttle suits. It's going to be a fun engineer exercise. -- Greg D. Moore http://greenmountainsoftware.wordpress.com/ CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net IT Disaster Response - https://www.amazon.com/Disaster-Resp...dp/1484221834/ |
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