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SpaceNut,
SpaceX has proven that orbital class rockets don't have to be as expensive as those produced by ULA, especially when they can be mass-produced and are partially or fully reusable. SpaceX has been making plenty of money, they're simply spending more money on development work than they're taking in from operating revenue. In short, it's that old spending problem that so many people, even ones in business, fail to appreciate. There is not an unlimited pot of money or other resources to work with. When it came to launching Starship, SpaceX should've used the pad at KSC that they already paid to refurbish and use for that purpose. Instead they spent a ton of money on building pads and associated infrastructure at Boca Chica that may prove unusable, because their super heavy lift rockets will fly over populated areas. All of the vertical launch facilities are located on the coastline, because flying an orbital class rocket over populated areas is forbidden, and for good reason.
They should've applied for a permit to fly Saturn V class rockets from Texas prior to breaking ground, if they expected to have FAA's glacially slow approval process completed in time for the first Starship to fly. They should not have flown a gigantic rocket without a permit, either. FAA was willing to overlook that, but EPA is not willing to overlook flying a Saturn V over populated areas. I'm generally not a fan of bureaucracy, but understand the concern of EPA regarding space flight over cities. If Starship proves to be boringly reliable, then SpaceX's Boca Chica launch site may still get approved in the future.
I understand what SpaceX is trying to do (co-locate the rocket factory and launch pad), but there are also practical considerations that prevent such plans from coming to fruition. That's why Boeing fabricates STS / SLS core stages at the Michoud Assembly Facility, but flies from KSC. ATK fabricates SRBs at Promontory, Utah, but again, those giant solid rockets fly from KSC. The other alternatives are Vandenberg and Wallops. You can attract and retain inexpensive skilled labor in Texas or Louisiana, because the cost of living is low relative to California or Virginia or Florida, which is why rockets get built here in Texas and in Louisiana.
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This is Louis's original deal-breaker list from the post that started this thread.
There are a number of deal breakers that could yet stop Space X Mars Mission:
1. Lack of funds.
2. Opposition of US government.
3. Failure to develop BFR.
4. A Challenger-type disaster.
5. Failure to develop the required life support and propellant plant.
6. Failure of the initial cargo mission.
7. Failure of test landings or other tests.
8. Opposition from US government, NASA or UN.
But also:
9. Inability to guard the health of the crew against cosmic radiation.
Now, I see little or no difference between items 2 and 8. I would hope by now that we have dismissed item 9, which certainly bothered him 3 years ago. That leaves item 1, and items 3-7, in addition to government opposition as embodied in items 2 and 8.
Spacex is certainly working item 3; that is what Boca Chica and the new Raptor factory to be built in McGregor are all about. If they don't screw it all up being too cheap at buying out the too-close neighbors. And debris from one of the exploded test Starships has already been thrown 5 miles. So it's not just Boca Chica Village; I'm talking about debris thrown all the way to the edge of Brownsville.
Item 1 is a real deal-breaker, and has been discussed as such, just above.
Items 4, 6, and 7 are inevitabilities. They WILL happen. The trick is knowing how to get past incidents like those. Being a privately-funded concern, they can do a better job of learning from mistakes and getting on with the job, than any government lab can. That's not to say they will, but the possibility is better for private entities.
The main "trick" is making sure your incident was not the result of a bad management decision. Musk is a visionary, yes, but that makes him vulnerable to making bad decisions, like so many other visionaries. Musk needs some Shotwells around him to keep him from doing that. Being too cheap in buying out the too close neighbors is EXACTLY the sort of bad management decision I am talking about!
Item 5 is a bigger deal-breaker than anyone seems to suspect. Musk has his hands full just trying to make Starship/Superheavy work. He is quite clearly counting on others to work the issues of life support and propellant-manufacturing equipment. The deal-breaker here is that no one else has bellied up to the bar and seriously addressed those issues yet. Lab-scale play-toys are NOT massive manufacturing plants! None ever will be.
Now, without the life support equipment, no crewed Starship will reach Mars with its crew still alive. Nor would they live very long on Mars even if they did arrive alive. And without the propellant manufacturing equipment, that trip is a one way suicide mission ending in a dead crew no matter what. Dead crews are what usually result from bad management decisions. Such as Apollo 1, Challenger, and Columbia.
There, does that take care of Louis's original list?
GW
Last edited by GW Johnson (2021-12-11 15:18:10)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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GW,
Design analysis and trade space and cost estimation (fairly comprehensive):
Actual working hardware analysis (real honest-to-goodness "shipping container mobile" industrial scale hardware):
Actual working synthesized CH4 plant (European- the Falkenhagen P2G Plant, commissioned in 2017):
Innovative large-scale energy storage technologies and Power-to-Gas concepts after optimisation
Believe it or not, the Europeans have already "bellied up to the bar". ESA supplies service modules to NASA, so why not P2G, as well?
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No one else aside from Nasa plus contracts are attempting to make a Saturn V class ship as they are all still in the Falcon to heavy area of manufacturing. Contractors such as Northrup, Boeing and Lockheed have access to or have made life support but the stage we need is longer than what supports the ISS to which Starship will need to do as well.
The real issues for starships we have talked about in the number or propellant loads to boil off, number of launch cycles to perform that function over a short period of time is problematic, not looking for AG is another, having issues of surface landing another, and the big one is manufacturing fuel to make a return home possible which is true even for the others with a smaller ship.
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SpaceNut,
I actually think full and rapid reusability and orbital refueling are far more important than the size of the rocket used. So long as the rocket has 2 sequential stages, is fully reusable, and is fully capable of flying again within 24 hours, then any 50t payload class rocket fits the description of something that can be used for human exploration of other planets.
We've already discussed why SSTO is a bad idea, even if it's technically feasible to do, due to the substantial payload mass penalty imposed by SSTO. That's the physics of orbital flight from Earth dictating to us which solutions provide the most payload for the least cost. The purported simplicity benefits of SSTO never seem to pan out, either, due to the extreme material requirements dictated by such solutions. Even though it could be done more easily using newer materials and engines, the payload mass fraction of TSTO remains superior because less propellant mass is expended to push the orbital portion of the vehicle, plus payload, to orbital velocity.
The high temperature tolerance of a welded stainless sheet steel booster make it feasible to get away with zero insulation, and that's 2/3rds of the cost of a rocket. That's why Starship has a stainless steel booster and upper stage, which requires minimal thermal protection system (TPS) due to the thermal soak capability of the stainless steel. For full reusability, only the upper stage is penalized with TPS mass. A SSTO would be fully penalized with TPS mass, rather than 1/3rd penalized. It doesn't matter how big or small the rocket is, either, with respect to that point.
Air launch can be done at high subsonic speed in the stratosphere, which puts you above 2/3rds of the planet's atmosphere and permits engine optimization for improved Isp, but the propellant mass required to achieve orbital velocity doesn't change much, so at best your rocket's first stage can be perhaps 5% smaller for a given payload delivery capability, most of which is rather cheap propellant. That's significant, but it's not game-changing. In practice, that performance increase is often offset by the use of easier-to-store but lower-Isp solid propellant rocket motors. If the rocket uses liquid propellant, then an orbital class rocket with a 500kg (to LEO) payload is roughly the size and weight of the LGM-30 Minuteman ICBM. The payload mass fraction of the liquid-fueled Virgin Galactic LauncherOne rocket is 1.93%. The all-solid Pegasus XL air launch rocket had a 443kg (to LEO) payload and 1.92% payload mass fraction. The payload mass fraction was so similar, despite the lower launch weight of Pegasus XL, due to the high thrust advantage of solid rockets. Falcon 9's payload is 22,800kg (to LEO), with payload mass fraction is 4.15% for comparison purposes, so the air launch advantages do not appear to offset higher efficiency engines or staging. Rocket Lab's Electron rocket, which is much closer in size to LauncherOne than the Falcon 9, has a payload mass of 300kg and a mass fraction of 2.36%. Therefore, the primary advantage of an air launch is the ability to launch to any orbit at any time from any civil airport as a starting point, not an increase in payload mass fraction for a given total launch vehicle weight. The first and second stage propellants of Virgin Galactic LauncherOne, Rocket Lab Electron, and Falcon 9, are all LOX/RP-1. StratoLaunch is the largest air launch carrier aircraft ever built, which limits the total launch vehicle mass to 230,000kg.
Saturn V's first stage burned through 534,000 gallons of propellant (203,000 gallons of RP-1 / 331 gallons of LOX) in about 2 minutes 41 seconds. The first stage breaks Mach 1 after about 66 seconds of flight, so it used 199,006 gallons of propellant to achieve that velocity. Therefore ~37% of the first stage propellant mass was consumed to reach Mach 1, while the other ~2/3rds swiftly accelerated the vehicle from Mach 1 to Mach 8.
Long story short, SpaceX's ground-launched Starship "got it right" when it comes to launch vehicle cost control by using the cheapest suitable materials, simplest orbital launch method that has been proven to work well, and highest practically achievable payload mass fraction.
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We are still waiting on the first to orbit an back to show how well that protection system stays in tacked as we have seen tiles come off just in the sub orbital stuff and that can spell disaster to a rocket holding a crew.
We are also looking to see a much higher speed on entry from orbit as well to shed that speed before firing up those engines of which that has been a problem as well to get them all on.
Lastly those spindly legs on a possible not on target landing shift by air cross winds could topple that rocket at its final last meter to go on a fully prepared site that's got to be a problem for use on the moon or mars.
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SpaceNut,
TPS has always been problematic and I've yet to see a practical reusable TPS without extensive refurbishment. Given that the Raptor series of engines are still going through continuous production process improvements, it's unavoidable that some manufacturing defects will be discovered along the way. The landing gear on the current prototypes is clearly unsuitable for rough field touchdowns, but I expect that will be addressed the moment after the first prototype topples over and explodes while attempting to land on sand.
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Lack of public interest might kill it and one deal breaker but be simply the fear exploring the fear of doing it, if NASA robots scouting ahead can not find enough Energy and Water out there to sustain a base them perhaps they might get Cold Feet, JPL and other Space Agency mapping out chemicals and resources of Mars is a great step forward, I also found the Chinese experiment growing plants on the Moon interesting even if most of them died after a few days. The Moon is a safer closer site but I do not think the public is so interested in the Moon. There might also be issues with supply or communicating with Earth, logistic problems perhaps, dust can kill solar panels interrupt communication and supply, however there are always new ways to transmit for example the MTO experiment, new updates in power and electric cells or new methods now being used to get to orbit faster and cheaper.
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Mars_B4_Moon,
It's hard for the public to stay excited about human space flight when there's been so many promises of real action, yet so little tangible progress delivered. Most people can only be enthusiastic about seeing the inside of a 20+ year old space station for so long before it's no longer interesting to them. Are they supposed to vicariously "explore the inside of a tin can"? Once you've seen it, you've seen it, and that's it. SLS and Orion have been in development for longer than Saturn V and Apollo existed as programs of record. All that money spent, merely to go back to the moon in an even less affordable way than we did using Saturn V and Apollo. NASA had to contract with SpaceX so that they could actually land on the moon, because they blew all of their money on an expensive rocket and capsule system, and then had nothing left for a lander, or even a suitable upper stage to take the capsule to lunar orbit. The rocket and capsule system are still not ready for launch.
The robotic space exploration program sets realistic goals and plots realistic trajectories towards those goals. They're very methodical about the engineering methods used to design the vehicles and the incremental approaches taken to exploration. The object of interest is first reconnoitered from space, basic data about atmosphere / temperatures / pressures is gleaned by atmospheric probes, stationary landers gather more detailed surface data from specific sites, and then increasingly sophisticated rovers are sent down to explore the surface in a mobile fashion. Most recently, a "Mars drone helicopter" has provided an aerial method for surface observation in conjunction with a rover.
I'd rate our robotic exploration program as a solid 8 out of 10. Most or all of the program objectives make sense, the missions are well-planned and well-executed, and most of the time they're successful. The associated hardware and missions also suffer from cost and schedule overruns, but I can stomach a little extra money or time spent when I know that at the end of the development cycle, there's a real mission going to some place that we've never been before. Each mission goes to a different place or does something fundamentally new, so real knowledge of true "unknowns" is gained in the process. Even the telescopes are both different and improved upon. Each instrument has been either dramatically improved or different in material ways that are necessary fill in gaps in our knowledge base. We started with visible light and near-IR with Hubble, then designed / developed / deployed James Webb. We stepped up our telescope game to a level wildly beyond what Hubble was capable of. Ditto for the various other missions. We've spent quite a bit of time on Mars, Jupiter, and Saturn, but have almost no comparable knowledge of Mercury, Venus, Neptune, or Uranus. If we'd devoted the money squandered on SLS and Orion to actual exploration, then we could've had a much richer knowledge of those other planets. I would like to see increasingly sophisticated probe missions sent to the inner and outer planets, similar in scope and scale to our Mars exploration campaign.
I'd rate our current human space flight program as a 4 out of 10. They've done nothing for longer than my entire life, and I'm over 40, that couldn't be accomplished from the ground using robots, apart from watching the health of our astronauts slowly deteriorate while they do laps around the Earth. They've gone nowhere but LEO or an orbital space station during that time, which is not "exploring" anything. If it were up to me, I'd confiscate NASA's entire human spaceflight program budget, in order to give the money to people who were serious about real exploration or worthy program objectives that contribute to long duration human space flight, such as artificial gravity or radiation protection or fully reusable launch vehicles or nuclear thermal rocket engines or more practical solar electric thrusters. It's plainly obvious that NASA is not serious about real space exploration. Our once world-class human space exploration program has been reduced to a welfare program for PhDs and defense contractors. I'm starting to wonder if I'll be dead before they send astronauts somewhere besides LEO.
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How much water for Mars must we find Mars_B4_Moon?
I would assume that the "find enough Energy " has to do with solar energy derived?
I do believe that we could go now with many of the current items but its got to be planned with in those constraints of limited crew and with a preloading of the landing site to ensure safety while performing a mars mission.
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SpaceNut,
We need a thoroughly flight-tested super heavy lift launch vehicle design before we can go anywhere else besides LEO. At the moment, absolutely nobody has one of those ready to go. Some designs are further along than others, but until we prove that our transportation system works as advertised, we're not going anywhere. Falcon Heavy is not human-rated and was primarily intended for heavy GEO satellite or robotic exploration missions, so we need SLS or Starship to complete a successful launch (and successful recovery in the case of Starship). I believe both rockets can work, but seeing is believing.
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Since Falcon is what the heavy is made from by virtue of that its should be considered human ready as we use it to bring humans to the ISS.
That is 63 mT to orbit for the heavy launch and its cheap...
Design a refuel-able engine and tank to push what we use to mars that fits into 63 mT sent empty to orbit. Use a tank for refilling it for same as the starship. Send up a mars landing stage similar to the falcon to dock with it sent up empty to be refilled capable of landing with an intact capsule to mars surface with its crew. Leave what you went out to mars in orbit to dock with later after you transfer to the mars lander. Use the preload mars cargo to refill the lander to return to orbit with the crew. Use all other gear for the stay on mars.
A mars falcon modified lander would be smaller and not requiring a second stage unless its helpful for a scaled design. Sure the cargo section could be expanded to bring extra stuff to the surface and since its not needing the heat-shield one can extend the capsule to the fullest of usable area.
Go with 3 minimum for crew and max of 4 to make it stay with in limits.
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