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$75 million for NPP; program level funding for a variety of projects relating or pertaining to NPP development. We have to prove the technology; theory differs from practical application, right?
We might differ on opinion/perspective, but NERVA was killed due to political considerations relating to the SALT and the Outer Space Treaty. Everyone (competitors and allies alike) gets really nervous when enriched uranium is placed on a rocket.
NERVA may be superior technology, but if political constraints preclude it, we need to need to be pragmatic and support research and development in technology areas that can work around that.
PS. Enjoying your blog.
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Well there's stupid, there's stupid and wrong, and there's stupidly wrong.
I'd put your comment in the latter category. There isn't another person on the planet who has been more interested in getting to Mars or who has a clearer vision about how to get there and why. Not a serious Mars nutter? On that basis, Tiger Woods was never a serious golfer and Roger Federer has no interest in winning tennis matches.
Because there is zero commercial advantage.
What's that? A CEO who sells rockets plays up a vision that, by the way, involves selling more of his rockets? His interest in Mars is self-serving; great for Human to Mars advocates as a means to an end, but he is not a serious mars nutter.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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okay. sky is blue. tides change. sun rises in the east and sets in the west. musk will put people on mars in 6 years using as yet to be built rocket, on a lander that doesn't exist, in space suits that don't exist, with power systems that don't exist and a return strategy that doesn't exist.
i'm stupidly wrong. i smell too. i am stinky stupid wrong.
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I smell some sort of argument brewing between Louis and Clark. Wish that wouldn't happen.
As for why NERVA was cancelled, when it shut down between 1972 and 1974, putting uranium things atop rockets was not a public fear issue, that BS came later. That time frame predates the SALT treaty stuff by about 2 decades, as well. The outer space treaty precludes weapons in space (nuclear or not), not nuclear propulsion. Not even nuclear pulse propulsion.
Interpreting the treaty to preclude such things came later, when the public had become brainwashed to fear anything nuclear at all. Often, there is considerable disparity between what I remember from those times, and what younger folks claim about those times today. But I was there, I remember!
My first real aerospace work was supersonic wind tunnel work regarding shuttle reentry, before that shape was finalized. This was in 1972. It might have been graduate student slave labor work, but it was real aerospace work. I did a short stint at LTV Aerospace working on the "Scout" satellite launcher in 1974. Entered the work force "for real" in December 1975, working rocket and ramjet missile propulsion, and did my first designs with a slide rule. That was over 40 years ago, guys! Yeah, I'm an old fart!
BTW, the Russians flew (and fired) a 23 mm cannon in space aboard Almaz, about 1970-ish. Would that be a violation of the outer space treaty? It's only an opinion, but I think so.
GW
Last edited by GW Johnson (2018-03-22 12:03:37)
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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No argument from me. Just findings ways to be more agreeable with Louis. If you can't beat em, join em.
I'll have to go back to my history books on NERVA since my timeline is off; my overall understanding is that SALT/Outer Space treaty have had a lot to do with limited funding and investment in developing nuclear options for space power. The political will/cost was too great and national interests were better served by limiting development for arms reduction gains.
At this point, anti sat technology has progressed to make much of the non-militarization of space moot. DOD is doing some serious investment in "launch and replace" (which is the point of SpaceX's launch architecture BTW) since most strategists conclude that US space assestswould be wiped out in the opening salvo a real conflict.
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Regarding Musk and his Mars vehicle:
As near as I can tell, the "BFR" properly refers to the first stage booster rocket, which is a descendant of the recoverable Falcon first stages. It's still a clustered-engine configuration, just scaled-up and using a larger engine. I forsee the technology of carbon fiber composite cryogen tanks as the pitfall that may trip them up for a while, not the basic rocket design approach.
The upper stage could be termed "ITS" or "BFS", that has yet to become settled. Solar power "wings" for it should not be a fundamental risk, we (collectively) have been doing that since the early 1960's. I don't really think the re-entry heat protection scheme is the risk issue either. It combines the at-angle lifting of the shuttle with their PICA-X material. Both have been separately demonstrated. If the cryo tanks and engines work in BFR, they'll work in BFS as well.
My prediction for the big risk with BFS is different than most folks would predict: I think the footprint is too narrow for the vehicle length to be landing on rough, unprepared ground. All the things that have landed by retropropulsion so far have had a height/footprint width ratio at or under 1, and for good reason.
My prediction of the biggest risk for the combined BFR/BFS system is also different than what most folks would think. These BFR things are too big to be moved significantly once they have landed. Musk intends to land them right on the very patch from which they are to re-launch. He depicts a gantry crane for placing the BFS atop the BFR, but I think reliable landing location precision that tight will prove elusive.
Before this is over, I predict he will have to move landed BFR's to the pad adjacent to his gantry crane. He currently isn't planning on having to do that, and that lack is risky.
Running a few sequenced missions to Mars with this thing to emplace equipment, is something that does not require big crews or atomic electricity to accomplish. Building a real base requires both, plus a whole lot of BFR/BFS flights. As he has said, he's trying to supply the transportation, "others" are going to have to bring the atomic power and base components to the table.
GW
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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I don't know if you remember it, but our first ASAT was a small vehicle launched from a fighter jet. One of the things I did at LTV was to define a one-off "Scout" configuration that could catch up a Minuteman-3 in flight, to test the guidance for that ASAT. That test mission made the cover of Aviation Week, about a year after I did the feasibility study for it.
What you say about space nuclear being limited by treaty constraints was true after about 1985-ish. And ever since, especially the arms reduction stuff in the 90's. NERVA was killed by NASA when Nixon killed Apollo. They literally saw no need to continue the almost-ready-to-fly project, since Apollo was dead, and by extension, the manned Mars mission, too. Nixon's executive order killed (very specifically) all human activities outside of LEO.
GW
Last edited by GW Johnson (2018-03-22 12:28:52)
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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I hope you will tolerate my post GW.
I am nervous about the same things. For instance the ice and rock mixture at Utopia Planetia, apparently contains significant voids, probably sublimated caves under the ice. They estimate that the specific gravity of the mix is less than pure ice even though the mix is 15-50% regolith. So, that makes me nervous.
If they had side thrusters that could help steady the device when it landed perhaps that would be of some benefit, but if the spot is bad, they are dead.
However as for the crane which also makes me nervous, perhaps they can after landing clamp some buttressing extensions onto the legs to stabilize it for crane use. However that is extra dead mass, unless you can salvage and repurpose that material later for something sufficiently useful. Maybe metal for electric motors? Steel, Iron?
Done.
Done.
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I had a chance to tour the El Segundo facility a couple years back and talk shop with one of the project managers for launches. Musk implemented a software development code check-in/check out methodology for managing the line. Novel. BTW, they burn through their human capital at a significant clip, so I think an unaccounted risk is simply not having people in place to execute.
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Yeah, they do have turnover. They work their people very hard. 60+ hour weeks are common. Only the young can tolerate chronic overtime like that. Which explains why they have almost no one aged 45+ in their workforce.
I dunno if that kind of human resource "management" is coming from Musk himself. But it will eventually bite them in their own ass to be operating that way. Not sustainable for the long haul.
That kind of human resource "management" is (or at least was, in my time) a court martial offence in the military. You must protect your command, that is (or was) the mandate. And it is (or was) your people that comprise your command. Not your ships, your tanks, or your planes. Your people.
Few civilian CEO's ever subscribed to anything like that. My dad was a successful engineering manager at LTV (he retired after 30 years' service, as their chief of airframe design, then two steps below the corporate CEO). He told me long ago that a manager only had 3 things to manage: money, things, and people (I would now add the phrase "over time" to that). He said that of those three, only the people had feelings and motivations, and that it was people who create the other 2. So, if you take care of your people, you have done 90% of your manager's job.
Very unusual in a corporate manager. But then my dad was an unusual person. I think he learned this management approach when he was in the Army Air Corps, flying B-25's, at about age 20.
GW
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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i understand it comes from Musk. Friend of a friend kind of deal though, so who knows.
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GW,
Resurrecting the old NERVA technology requires manufacturing fuel rod assemblies. That was the part of the technology that was "lost" over time. Apparently nobody thought the manufacturing process was important enough to commit to paper or perhaps someone was so overly-concerned with secrecy that it was squirreled away somewhere and then subsequently destroyed years later because they didn't recognize the importance of what they were destroying.
All the other details regarding how to build a flight ready reactor were not lost, but that was a lot of basic rocket engine design stuff where hot flowing hydrogen was involved. We've made numerous improvements to materials and fabrication techniques used in that knowledge base since then. Even if we hadn't, the tech developed for Project Timberwind is also still available and also an improvement on NERVA.
The fuel and control rod assemblies are fundamental to the basic design and that is what NASA is spending their time and money on. Everything else but the overall core design is very well covered by current in-use technology.
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My prediction for the big risk with BFS is different than most folks would predict: I think the footprint is too narrow for the vehicle length to be landing on rough, unprepared ground. All the things that have landed by retropropulsion so far have had a height/footprint width ratio at or under 1, and for good reason.
Presumably this is something that can easily enough be determined in Mars-like conditions on Earth: attempt a landing in a rocky desert area.
I found this in the Reddit AMA with Elon Musk back in October 2017, which is relevant:
Q. Why was the number of BFS landing legs increased from 3 to 4?
The BFS/2016 design used three landing legs, while the new BFS/2017 design uses four.
What is the motivation behind this change?
A. ElonMusk: Because 4 improves stability in rough terrain
So, as you might expect, Musk is fully aware of the issue. I presume the legs will have some hydraulic element so that if one leg lands on a boulder it can compensate. I guess landing on an unstable boulder is the issue, though.
I think this comes down to landing in a boulder field that has rocks below some desired minimum size.
One possiblity is for Mission One to land close to a previous landing site e.g. a Viking Lander site where we know with a reasonable degree of accuracy what the boulder field looks like.
My prediction of the biggest risk for the combined BFR/BFS system is also different than what most folks would think. These BFR things are too big to be moved significantly once they have landed. Musk intends to land them right on the very patch from which they are to re-launch. He depicts a gantry crane for placing the BFS atop the BFR, but I think reliable landing location precision that tight will prove elusive.
Before this is over, I predict he will have to move landed BFR's to the pad adjacent to his gantry crane. He currently isn't planning on having to do that, and that lack is risky.
I presume you are talking about landing back on Earth (or have I missed something)? What about a moveable platform? Would that be a solution?
Running a few sequenced missions to Mars with this thing to emplace equipment, is something that does not require big crews or atomic electricity to accomplish. Building a real base requires both, plus a whole lot of BFR/BFS flights. As he has said, he's trying to supply the transportation, "others" are going to have to bring the atomic power and base components to the table.
The price of PV has dropped hugely and continues to do so. There are hundreds of new PV technologies being worked on which can further reduce cost and complexity. PV panelling on Mars is not subject to the same level of environmental stress as on Earth. We are probably only a couple of decades away from effective solar power satellite and beamed orbit-to-surface energy.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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The dry mass of the BFS is supposedly 85t and would nominally contain a 150t payload. The latest incarnation of the M1 tank weighs about 72t. When this machine lands, it weighs more than 3 M1 tanks and is 48m in height. That's a pretty tall order for a vehicle that must land on uneven terrain. It may not be impossible, but it will be interesting, to say the least.
What I want to know is this:
On Earth the Aluminum crush tube is removed and replaced before the Falcon booster is flown again. Any faulty engine components are also replaced in a near clean room environment. How do they intend to do all that on the surface of Mars without getting dust in the sensitive parts of the engine? This thing has to have retractable landing gear that uses hydraulic pressure and/or springs instead of crush tubes to be reusable and the difference between the dynamic load upon impact is far in excess of the static load. It had better be a near perfect landing.
I guess we'll all find out eventually, but like I said before, interesting. I foresee some design changes as testing progresses. The colonists probably shouldn't watch the B-reel.
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I'll be surprised if they actually do pull off the current proposed architecture of having a launch from Terra, refuelling in orbit, landing the entire thing on Mars, refuelling it there, and returning to Terra. It's more likely, I think, that they'll end up using it as a super heavy launch vehicle with (some) orbital assembly and dedicated landing craft and interplanetary spaceships. Using the same vehicle for every leg of the journey doesn't make sense.
"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony
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IMHO, the current SpaceX mission architecture is very optimistic. I tend to agree with GW about vehicle stability and landing on unprepared rough ground. Yes, Elon Musk is thinking big, but he still needs the Red Dragon "surveyor missions." And then an intermediate crewed mission to prepare the landing site for BFS.
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It makes sense in terms of development costs, particularly when you can use the same set up for orbital & lunar tourism, E2E airline-style transport, satellite launches and ISS supply.
However, I must admit Musk's approach wouldn't be my first choice. Rather than try and set up propellant production on Mission One, I think my instinct would have been to have opted for taking an ascent vehicle (plus fuel) as part of one of the cargo BFRs. Use that to then rendezvous with a return BRF in Mars orbit.
But, then, if he can pull off the propellant production, his approach does have a lot going for it.
I'll be surprised if they actually do pull off the current proposed architecture of having a launch from Terra, refuelling in orbit, landing the entire thing on Mars, refuelling it there, and returning to Terra. It's more likely, I think, that they'll end up using it as a super heavy launch vehicle with (some) orbital assembly and dedicated landing craft and interplanetary spaceships. Using the same vehicle for every leg of the journey doesn't make sense.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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You don't accept Musk's claims about the the additional leg providing more stability? (see my quote above from Reddit AMA).
What about if they land in an area we know about e.g. next to the Viking lander, or near where one of the Rovers landed, where we can see the boulders are not excessively large?
IMHO, the current SpaceX mission architecture is very optimistic. I tend to agree with GW about vehicle stability and landing on unprepared rough ground. Yes, Elon Musk is thinking big, but he still needs the Red Dragon "surveyor missions." And then an intermediate crewed mission to prepare the landing site for BFS.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Louis, stability is determined by having the center of mass fall well within the area created by the points of the landing leg's contact with ground. The wider span of the legs thereby can accommodate a less than perfect landing better. By making the point of attachment to the fuselage of the rocket a bit higher would help, but the landing gear span needs to be wider. I suspect Musk will ultimately "get it right," or he will "get it wrong and go broke." But--SpaceX has been impressive with the end results to this point, but enthusiasm cannot replace competent engineering or repeal the laws of physics. This is what GW was concerned about; look at the lunar landers.
Last edited by Oldfart1939 (2018-03-23 09:52:41)
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Louis,
The landing gear stability issue can be verified here on Earth before it ever goes to Mars. If stability is a problem in testing, then a new design has to be incorporated into the vehicle to assure stability. Mere presumption that stability won't be a problem is not indicative of the soundness of the design.
Steel and steel reinforced concrete have very little "give" to them, even if the landing pad itself is moving. A landing gear system can be devised to land an aerospace vehicle on an incline, such as a rocking and rolling ship. If the flight deck of an aircraft carrier deformed to any significant degree when a plane landed, then that would be a problem for the aircraft designers. The Falcon boosters come down fast enough to plant themselves on the drone ships.
BFS will likely have to have a lower vertical velocity, or rate of descent, to avoid coming down so hard that it damages the vehicle or causes the ground to give way. I forgot that on Mars this thing would only weigh 89t fully loaded, with no propellant, or slightly more with residuals, and approximately the same on Earth with no substantial return payload. There must be load limits of some kind. It probably has to land fully loaded on Mars and empty on Earth to stay within those limits. This is no different than jetliners burning or dumping fuel to land, since most can take off heavier than they can land.
Perhaps the first BFS should be the propellant plant and the second BFS should be the batteries / solar panels and secondary propellant storage. Both should stay there to service subsequent BFS flights to Mars. All I'll say is that they better make damn sure those first two ships are sitting on top of a massive buried glacier. That problem would be why NASA needs to conduct manned scouting missions using a hardware set more appropriate for exploration purposes. Nobody really knows for sure what we're going to find until we eyeball it.
Wherever the best H2O and Sulfur deposits are, that's where we want the first colony. The need for water should be obvious and the stinky yellow stuff can be combined with a finely ground aggregate and heated using microwaves to 3D print shielding around inflatable structures. That way, the habitats can contain fewer protective layers and be movable using small tracked vehicles.
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"Steady-state" overturn stability is very easy to determine. The inertia force resultant vector from the center of mass must point to a spot in the landing leg plane that falls within the polygon defined by the landing leg footpads. This inertia force vector includes the static weight vector, plus any dynamic mass x acceleration terms that may also be acting. (This is also how you figure whether a car will flip over, going around a sharp curve. It's well-proven.)
The "dynamical" overturn stability involves things "outside the pale": (1) one leg settling on a rock taller than the stroke capability of the leg, and (2) one leg settling briefly on a tall rock, then slipping off, an event that happens far faster than the leg can stroke.
Musk's BFS meets the steady-state stability scenario, but is vulnerable to the dynamic scenario. There's no reason why his ship can't land on Mars, but its reliability doing so is far higher, if those landings are restricted to pre-prepared landing fields. That's part of why he originally talked about Red Dragon doing "pathfinder missions". He knows about this risk.
Something about the scale of Red Dragon needs to drop a robot bulldozer on each selected site to grade-off a pre-prepared landing field without the offending boulders. That's what's missing here. If NASA wants a role in sending the first men to Mars, there it is.
GW
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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We are still information-deprived about the subsurface of Mars and the resulting loadbearing capacity. This is really why we need a exploration/pioneer mission before launching a full-bore BFS there. Even with a net worth of $22 Billion, Musk cannot afford to throw away one of his new cargo bearing vehicles. Maybe at some point, the caution bug will bite him a bit harder? I suppose there could be an alternative upper structure for the BFR? Something on a smaller scale w/o such a large mass, and capable of return to Mars orbit w/o refueling.
GW-
Refer to my post #41 above.
Last edited by Oldfart1939 (2018-03-23 11:49:53)
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Prior to landing C-130's on rough fields, the USAF uses a ground compaction test equipment set to determine whether or not the intended landing surface will support the weight of a loaded C-130. A small robotic rover with test equipment to include ground penetrating radar, regolith compaction analysis probe, and radio and/or IR strobe beacons for guiding the BFS into the landing area is probably a really good idea. Anyway, that's how we do it on Earth.
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Yes, I agree. Given Space X's architecture, I think that makes sense - a robot rover to examine the ground and maybe lay down transponders.
But from what I have read before it sounds like Space X are not going to unload the cargo BFRs robotically, prior to arrival of humans, so that would preclude a robot rover. That said, why are they sending them two years in advance then! Confusing!
I suppose an alternative approach might be to launch a small robot lander from Mars orbit (from the human passenger BFR) to give the landing zone the once-over.
Prior to landing C-130's on rough fields, the USAF uses a ground compaction test equipment set to determine whether or not the intended landing surface will support the weight of a loaded C-130. A small robotic rover with test equipment to include ground penetrating radar, regolith compaction analysis probe, and radio and/or IR strobe beacons for guiding the BFS into the landing area is probably a really good idea. Anyway, that's how we do it on Earth.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Well normal launch followed by a landing is 9 months of the typical 2 yrs and 7 weeks cycle so is will be that between landings given that the launches will be about at the same distance when the cycles converge again. That does not mean that the cargo landings need to be doing anything but they could. Compressing mars air would be a slow process that would take a bit of energy to do even if nothing else was done as the solar array feed is not deployed yet.
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