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Before Musk unveiled BFR/Starship, I had envisioned an intermediate sized "next step." Falcon 9 is 3.7 meters in diameter, and i was thinking of something of a pioneering Mars ship that would be 5-7 meters in diameter as a central core using 2 Falcon 9 as strap-on boosters. That would have been enough to send my crew of pioneers to Mars on more of a reasonable budget. It would have been enough for an exploratory mission with a smaller scale investment in infrastructure.
Maybe that's why he's the Billionaire? Gotta think big. Really BIG!
I heard on one of the websites (cannot recall which one) that there's a possibility that SpaceX might be able to get a temporary, or one shot approval of launch. That would skirt the Environmental Impact Study that would give a blanket authorization...
"COLORADO SPRINGS — The head of the U.S. Space Force launch enterprise said it is “unfortunate” that Blue Origin is taking far longer than expected to complete the testing and production of BE-4 rocket engines for United Launch Alliance’s Vulcan Centaur launch vehicle."
The Space Force isn't happy about Blue Origin's delays in delivery of the BE-4 engines.
Here's the link to the Space New article: https://spacenews.com/space-force-launc … re-on-out/
"improved Rocket 3. We’ll be taking a test payload from the Space Force."
It seems that they didn't improve it enough...
kbd512-
I didn't see the discussion of using fully tracked vehicles until tonight. I too like the enhanced mobility of an all-tracked vehicle, but there is a significant downside to them: Maintenance.
I was stationed in Germany during the early 1960's and the US Army was still operating M59 APCs, and then the then-new M113 models were introduced as I was getting ready to come back to the ZI. For an armored fighting vehicle, the standard was 9 hours of maintenance for every hour of operation. Maybe not as much for the APCs as for an M60 MBT. But tracks have lotsa parts, unless they are giant rubber bands like on the M2 half tracks. I've looked carefully at the Bobcat ads here on the Internet, and I believe they are still pushing wheeled vehicles over tracks. I think that it's not an either-or situation, but having some of both designs in order to fully evaluate under field conditions. Toyota has released photos of their Moon Rover, and it's a 6 WD vehicle with big wheels and hefty tires. Anything that will work on the Moon should work equally well on Mars.
GW-
Here's the Elon Musk interview part #1. https://www.youtube.com/watch?v=t705r8ICkRw
Go to 33:59 minutes to pick up the conversation about the Raptor design and where it's headed.
The interview of Musk by Tim Dodd is my source of the number of Raptors that will be used in later rockets being 33--or more. This was towards the end of either segment 2 or in the much shorter 3rd installment. Elon also states that the chamber pressure is quite high and results in high thrust.
GW-
I'll try to find the exact number that Musk stated about the thrust produced. It's a function of chamber pressure and it's up substantially over the earlier serial numbers. The Raptor isn't a mature design and is undergoing continuous upratings and weight per engine mass reductions. As he often states, the best part is no part. A lot of the plumbing appears more compact and smaller now.
GW-
Musk has recently stated that there will probably be 33 uprated Raptor engines on the fully loaded and operational booster vehicle. The thrust and efficiency seems to be rising rapidly on the newer serial numbered engines, and is probably why he's willing to throw the older ones in the drink instead of attempting to recover them.
Blue Origin suit stops work on NASA HLS contract with SpaceX
https://spacenews.com/blue-origin-suit- … th-spacex/
Thanks for your help in getting back to the Moon...not.
Here's another "take" from another commenter on YouTube;
https://www.youtube.com/watch?v=QExxT5ttAQs
This guy refers to the National Team Lander as the "Lobby Lander."
He really does a good job in making comparisons between BO and SpaceX proposals on technical merit and pokes holes in the BO critique of SpaceX which used outdated and incorrect information.
We now have BO suing NASA over the way they made their contract decision. This is NOT a smart move on their part. It seems that Bezos wants things his way--or else! It's a potential Public Relations gaffe of the highest order.
OK, I've been struggling along with a subsequent viral pneumonia which has sapped my energy level a lot. Trying to get back to my normal energy level has taken time.
In almost every manufacturing industry, the bean-counters always seem to have sway over the technical people. Same in the chemical process industry. I was pretty diligent about writing down what I actually did, and the stuff that worked for the bean counters in order for them to have enough left to count after the cost of manufacturing a product.
But as GW said above, it's the unwritten art that gets lost in time, and has to be reinvented time and time again. Dumb luck is just an unrefined and undefined form of this "art."
Here we are--talking about construction and materials flaws in Starliner. An even bigger problem await with the first flight of SLS, which we are told is "coming soon." It makes me wonder about all the attitude control thrusters on that bigger bird, and whether they succumbed to using the "cheaper valves?" Hopefully the "cost plus contract" made the more expensive valves attractive to the accountants?
My earlier comments on this thread never said anything about the impossibility of using algae, but I was focused on the manufacturing scale that would be required--enormous--and the amounts of liquid water that would be needed for growth of enough algae to be worthwhile. Algae needs more than water and sunlight; as there are other nutrients needed to sustain a living population of this prolifically growing plant. There is a lot more biology and chemistry involved than first meets the eye.
Based on GW's comments above, I tend to think that my "hypodermic syringe" design might work because of no real stress or folding would occur with a big "o" ring style gasket between the tank walls and the actual plunger. Gases could power the system and the actual pressure differential would not need be too great. This is where polymers like these advanced Teflons come into their own. Strong, "slippery" and reasonably flexible at the needed temperatures.
This is a question directed to GW. You commented on the valves utilized being the "cheap ones." As a chemist with some knowledge of engineering materials and processes, I'm wondering what they DID use? It seems that the ball portion of the valve was metallic. I would think that a type 316 SS was what they probably used, and Inconel would have been better although more expensive (in a relative sense) to SS. Even better in my mind would have been a ceramic coated Inconel valve which would have been resistant to damn near anything that could derive from NTO and a trace of moisture.
I'm gonna quote Forrest Gump again: "Stupid is as stupid does." I hope that Boeing is happy with their accountants making engineering decisions to save a few pennies. I, as a taxpayer, have had enough.
My off the top of my head response to this idea is: too resource, time, and energy intensive on the scale that's needed. This is a case for the acronym TANSTAFL.
It is now evident that NTO is the culprit, and moisture corroded the valves in a stuck position by the nitric acid formed.
https://spacenews.com/starliner-test-fl … ong-delay/
Starliner is now in the process of being de-stacked and the spacecraft taken back to the factory for additional work.
I would say that Elon himself may follow our forum, as he's a paying member of the Mars Society, Has attended our national meetings in the past.
In the worst case scenario, these polymers could be used as seals between a moveable bulkhead and the fluid being pushed by the gas pressure utilized.
Robert-
I suspect that the bladders could be useful additions to the tanker-only versions of Starship, using the bladders to squeeze out the propellants into the receiving Starship. There will undoubtedly be arguments over additional mass needed but will not be a throwaway item and will be reused as much as the service lifetime will allow. I'm familiar with these polymers only in passing, but they should work fine especially for the (l) Me, and probably for the LOX as well.
Many of these "self-styled experts" are new guys just looking for clicks. I really only follow 2-3 of the better pundits: Scott Manley, Tim Dodd, and Felix Schlang. These 3 seem to put a lot of work in their presentations and aren't just a computer generated voice over some stock footage. Marcus House also does a fair job in his accuracy.
This is mainly all good PR for SpaceX. Nothing more than filler for these daily posters.