Breakthrough In-Space Propulsion for Affordable Mars Missions

GW Johnson · 2016-11-11 10:00:30

These things are technology development items. We do not yet know that these things really work, much less what it really takes to build effective ones. Finding out those kinds of things is the point of funded technology development programs, and they cannot be run successfully the way you run production programs (although entirely too many managers try to do exactly that).

Building a vehicle to fly is different. You want to pull off-the-shelf, ready-to-apply technology items together to create your design, or else it is unlikely in the extreme that you will ever fly. Any new technology to be used had better have an off-the-shelf backup, and that new technology had better not be a major critical item for success. Examples that never flew because they depended critically on new technologies unready-to-apply at the time: X-30/scramjet, X-33/composite propellant tanks.

Both flight vehicle programs and new technology development programs are critical to progress, and both have to be funded and properly managed. But do NOT mix them. And do not apply something new, until you are sure it is ready. Composite tanks are ready now (Spacex helium tank problem notwithstanding), scramjet still is not.

GW

kbd512 · 2016-11-11 11:25:50

No human space exploration program in the history of NASA used off-the-shelf hardware. Certain aspects of those programs utilized technologies that were already developed to the point of being suitable for their intended purpose. Other aspects of our various human space flight programs utilized critical design elements that were literally developed as the need arose.

We talk about our space program as if it is not also a substantial technology development program. There is no set of current technologies that are completely ready for a mission to Mars. We've already spent many billions of dollars to develop chemical rocket technology, but those technologies will not make Mars missions affordable and therefore achievable within current and projected NASA budgets. Spending more money on chemical rockets will not cause the additional required funding to magically appear in NASA's budget when it is time to attempt a Mars mission.

Balking at spending a few million dollars to properly test new technologies that have the potential to save tens of billions of dollars a few short years down the road is not a very good plan for successfully sustaining a robust space exploration program.

Tom Kalbfus · 2016-11-11 11:37:57

Is there a deadline, is Mars going away? We need to spend a certain amount of money to get to Mars, why can't we fit that amount in an annual NASA budget without blowing up that budget? Lets say we can afford to spend X number of dollars per year, and the Mars people say its going t take Y dollars to get to Mars, so the formula for the number of years it would take to launch that mission to Mars becomes Y/X = the number of years it takes to launch that Mission to get to Mars! Why is that so hard?

kbd512 · 2016-11-11 19:06:34

Tom Kalbfus wrote:

Is there a deadline, is Mars going away? We need to spend a certain amount of money to get to Mars, why can't we fit that amount in an annual NASA budget without blowing up that budget? Lets say we can afford to spend X number of dollars per year, and the Mars people say its going t take Y dollars to get to Mars, so the formula for the number of years it would take to launch that mission to Mars becomes Y/X = the number of years it takes to launch that Mission to get to Mars! Why is that so hard?

Current chemical rocket technology makes staying within current or projected NASA budgets virtually impossible if the goal is to send humans to Mars in any reasonable timeframe. The chemical rockets we do have are far too costly and too complicated for that to be a realistic possibility. Small standing armies are required to design, develop, test, manufacture, and maintain infrastructure associated with chemical rockets. There are no chemical rockets in existence that do not require very specialized and expensive infrastructure to support.

If propulsion was essentially unlimited after a spacecraft or satellite was put into orbit, the costs associated with robotic and human space exploration would plummet to levels that virtually any industrialized nation could afford to pay for. If you'll pardon the pun, there would be an explosion of investments into space technologies by simply removing that cost barrier associated with current space exploration and exploitation technologies.

If there was an all-electric solution for achieving orbital velocity, virtually any reasonably well-funded university or corporation could afford to experiment with and thus benefit from investments into space exploitation technologies. Propulsion has always been the most insurmountable barrier to overcome. There are mature communications, power, and life support technologies suitable for space exploration and exploitation, but present propulsion choices are chemical rockets or ion engines that only very well funded government space exploration agencies and multi-billion dollar corporations can afford to use. That severely limits the practical effect that space exploration and exploitation can have for the average person. Most average people can't make the connection between microchips created for our space exploration efforts and their cell phones or laptops, either.

If the average person could go into space, obtain a lucrative job in space, and was constantly reminded of the benefits from space exploration and exploitation, then at some point in the not too distant future governments, businesses, and individuals would have that "A-ha!" moment where they all realize why our space program is so vitally important to the overall health and advancement of national and international economies.

SpaceNut · 2016-11-11 20:49:37

The business needs to be more than science, going around in circles before individuals can een get involved other than the few which are very rich at this point and that is why its still does not matter to the common man just us Space Nuts...

GW Johnson · 2016-11-12 11:06:04

"No human space exploration program in the history of NASA used off-the-shelf hardware. Certain aspects of those programs utilized technologies that were already developed to the point of being suitable for their intended purpose. Other aspects of our various human space flight programs utilized critical design elements that were literally developed as the need arose."

Kbd512 - that's just not true!

The Redstone was a pre-existing Army bombardment rocket. Both the Atlas and the Titan were pre-existing USAF ICBM's. Even the Saturns were pre-existing Army military rocket designs, just not yet built. And we already had pressure suits for the U-2. We already had rocket guidance from the ICBM programs.

It's true we designed the capsules our astronauts rode in, but the basic ideas for those were pre-existing experiences with instruments and animals sent into space on V-2's right after WW2.

The lunar lander was the closest thing to a from-scratch design-and-build. Both it and its trainer proved to be very difficult, too. Had it not worked, the moon landings would have been impossible until it did work. We were luckier than we had any right to expect.

As I tried to say above, the breakthrough ideas discussed here desperately need investigation! Something from among them (or similar) is going to work and turn things completely around. Eventually.

But when you decide to go fly, you do not solely bank on as-yet undeveloped technology, or you very likely will not fly.

Basic aerospace management 202: do not mix technology development programs and flight vehicle build programs. And do not try to manage them the same way, either. You'll be sorry if you do either of those no-no's.

As for chemical propulsion being too expensive for sending a man to Mars, that's just BS. Yeah, it's expensive, although in the last decade that price has finally started to decrease. Just not with NASA's rocket.

We could have sent a crew to Mars in the 1980's, with only what we had then. I don't think now that they would have survived the trip back then. It would have been an Apollo-like flag-and-footprints stunt, with a huge price, just like Apollo. But it would have been a man on Mars. Just likely a dead one.

We could have pulled off an Apollo-like Mars shot by the late 1990's, and probably gotten the crew home alive, and maybe even reasonably healthy. We knew enough by then to understand that we needed artificial gravity, large space in which to live, and that radiation threats cannot simply be ignored. It's still nothing but a pricey stunt. But it would have been a man on Mars.

The argument before us today is how to do more than a flag-and-footprints stunt, for less than a flag-and-footprints stunt price! This is important, because it simply costs so much more to send people to Mars than it did the moon. Why? Because the mission is so much longer in duration.

I'm sorry, but using the same expendable payload and expendable rocket ideas changes nothing from the Apollo-like flag-and-footprints stunt approach, no matter how cleverly we disguise it and cloud the issue with jaw-breaking acronyms. There is no way that throwing large things to Mars with a launcher that costs $1+B per launch will ever change that conundrum, whether or not you refuel there.

Any approach that can actually do more accomplishment for less money will look nothing at all like anything we have done since Sputnik! It will look more like the mid-1950's orbit-based ion ships with multiple landing rockets, or it will look more like Musk's giant general-purpose cargo container ship. Or like something nobody has thought of yet.

Whether it uses only rockets, or some electric propulsion in addition to those rockets, is less important than figuring out how to do this without all that one-way expendable horseshit we have have been doing all these decades.

We have the rockets, the electric thrusters, the advanced materials, and the knowledge of what is needed to keep a crew safe and healthy. We have a weath of knowledge about Mars, too. This can be done. We don't need to wait for some sort of "warp drive", we can do it right now.

GW

Last edited by GW Johnson (2016-11-12 11:34:07)

kbd512 · 2016-11-12 13:30:01

GW Johnson wrote:

Kbd512 - that's just not true!

I stated that certain components were off-the-shelf. However, many parts of the launch system were modified, and therefore not off-the-shelf. The Titan ICBM's and Titan lift vehicles were not the same rocket.

GW Johnson wrote:

The Redstone was a pre-existing Army bombardment rocket. Both the Atlas and the Titan were pre-existing USAF ICBM's. Even the Saturns were pre-existing Army military rocket designs, just not yet built. And we already had pressure suits for the U-2. We already had rocket guidance from the ICBM programs.

The Redstone lift vehicle minimally deviated from the design of the Redstone ICBM, but even that lift vehicle required new technologies. It never achieved orbital velocity, either.

GW Johnson wrote:

It's true we designed the capsules our astronauts rode in, but the basic ideas for those were pre-existing experiences with instruments and animals sent into space on V-2's right after WW2.

The point I'm trying to make is that there are no other aerospace vehicles that share much in common with space capsules or lift vehicles.

GW Johnson wrote:

The lunar lander was the closest thing to a from-scratch design-and-build. Both it and its trainer proved to be very difficult, too. Had it not worked, the moon landings would have been impossible until it did work. We were luckier than we had any right to expect.

There was almost nothing about the Apollo program that was heritage flight hardware. The F-1's, J-2's, Apollo capsule, and lunar lander were all purpose built flight hardware that never existed before they were developed.

Apart from the tiles from the Space Shuttle Program, Orion has nothing else in common with the Space Shuttle. New computers, new batteries, new life support systems, new alloys, new construction methods. Everything is scratch built. That's why it's taken years to develop the capsule into flight hardware and it has yet to fly in its initial configuration for human space flight.

GW Johnson wrote:

As I tried to say above, the breakthrough ideas discussed here desperately need investigation! Something from among them (or similar) is going to work and turn things completely around. Eventually.

If the Q-thrusters only work as well as they've been proven to work in the lab, in space, that would mean 70 day outbound transit times and 110 day inbound transit times for a 55t payload with a 1MWe power source. With the same power source and 27t payloads, which our much less expensive Falcon Heavy rocket could easily deliver to orbit, we could cut those transit times in half.

If the S-thrusters only work as well as they've been proven to work in the lab, in space, that would mean 10X more thrust than the Q-thrusters deliver, a tiny fraction of the power requirement of Q-thrusters, transit times of a couple weeks or less no matter the orbital phasing of our planets, and true assured access to Mars.

The Q-thruster and S-thruster technologies are the only real "game changing" propulsion technologies available in the near-term. FDR requires another ten years of development. No adverse test results or major technological issues have been encountered with development, but throwing more money at this problem won't likely solve it any quicker. The right people are on it and they're developing the technology at the pace they can maintain.

GW Johnson wrote:

But when you decide to go fly, you do not solely bank on as-yet undeveloped technology, or you very likely will not fly.

We're in agreement, but I don't think NASA received the memo.

GW Johnson wrote:

Basic aerospace management 202: do not mix technology development programs and flight vehicle build programs. And do not try to manage them the same way, either. You'll be sorry if you do either of those no-no's.

We don't have the technology to access Mars in a reasonably cost-effective manner because we're still pouring billions of dollars into chemical rocket technology development that can not and will not improve upon the status quo. Any Orion and SLS-based Mars missions will be every bit as unaffordable as the Apollo program was.

GW Johnson wrote:

As for chemical propulsion being too expensive for sending a man to Mars, that's just BS. Yeah, it's expensive, although in the last decade that price has finally started to decrease. Just not with NASA's rocket.

So the cost-aspect of going to Mars using chemical rockets has not been a major impediment, even though NASA says it needs a budget increase to do that?

I think we're all in denial about how insanely expensive chemical rockets are.

GW Johnson wrote:

We could have sent a crew to Mars in the 1980's, with only what we had then. I don't think now that they would have survived the trip back then. It would have been an Apollo-like flag-and-footprints stunt, with a huge price, just like Apollo. But it would have been a man on Mars. Just likely a dead one.

Technologically speaking, we weren't ready. You said it yourself. Nothing is as expensive as a dead crew. We're much closer to being ready today than we were in the 1980's, even if NERVA had produced flight rated NTR's.

GW Johnson wrote:

We could have pulled off an Apollo-like Mars shot by the late 1990's, and probably gotten the crew home alive, and maybe even reasonably healthy. We knew enough by then to understand that we needed artificial gravity, large space in which to live, and that radiation threats cannot simply be ignored. It's still nothing but a pricey stunt. But it would have been a man on Mars.

I have my doubts about that. The life support systems were nowhere near reliable enough, as we've learned from our experimentation aboard ISS.

GW Johnson wrote:

The argument before us today is how to do more than a flag-and-footprints stunt, for less than a flag-and-footprints stunt price! This is important, because it simply costs so much more to send people to Mars than it did the moon. Why? Because the mission is so much longer in duration.

Q-thrusters and S-thrusters will enable Mars missions at far lower prices than chemical rockets could ever reasonably be expected to achieve.

GW Johnson wrote:

I'm sorry, but using the same expendable payload and expendable rocket ideas changes nothing from the Apollo-like flag-and-footprints stunt approach, no matter how cleverly we disguise it and cloud the issue with jaw-breaking acronyms. There is no way that throwing large things to Mars with a launcher that costs $1+B per launch will ever change that conundrum, whether or not you refuel there.

If you told the US Air Force they'd have to throw their B-1 or B-2 bombers away after a few minutes of use, they'd look at you like you lost your mind. For some reason, nobody thinks twice about doing that with chemical rockets and then wonders why we haven't really extended our reach beyond LEO in living memory.

GW Johnson wrote:

Any approach that can actually do more accomplishment for less money will look nothing at all like anything we have done since Sputnik! It will look more like the mid-1950's orbit-based ion ships with multiple landing rockets, or it will look more like Musk's giant general-purpose cargo container ship. Or like something nobody has thought of yet.

I wholeheartedly agree. So why is NASA continuing this charade with Orion and SLS taking humans to Mars?

Whether it uses only rockets, or some electric propulsion in addition to those rockets, is less important than figuring out how to do this without all that one-way expendable horseshit we have have been doing all these decades.

GW Johnson wrote:

We have the rockets, the electric thrusters, the advanced materials, and the knowledge of what is needed to keep a crew safe and healthy. We have a weath of knowledge about Mars, too. This can be done. We don't need to wait for some sort of "warp drive", we can do it right now.
GW

The moment we test electric thrusters that don't use propellants in space and prove that they work in the vacuum of space just as well as in a vacuum chamber sitting in a laboratory, we've achieved nothing short of a complete windfall in propulsion technology development. I agree that warp drive is not required. However, access to the propellant-less propulsion from Star Trek or Star Wars or whatever would put routine exploration of the entire solar system within our technological capability.

SpaceNut · 2016-11-12 20:49:52

The one developing commodity there is one that is not being worked, nuclear power source for powering these up and coming propulsion methods.

As far as Cots go its not until we have competion to make the same part from other vendors will there be anything that will not be proprietarily made by or for the launch vehicle through contracts for them or by the owner of the launch vehicle.

The ISS docking is about the first piece that both Beoing and Space X must be able to share. While the ULA is a mix of lockheed and Boeing parts for creating a launch vehicle.

Void · 2016-11-13 08:43:33

I am just going to be a bit supportive of kbd512 here. This material is a bit redundant but it tilts towards support as well.
http://timesofindia.indiatimes.com/home … 398649.cms

The material compares thrust to that of a solar sail, in a favorable manner, but I think it is apples an oranges.

If somehow it does work, they do not explain why.

I like many others think it heats up virtual particles and makes them and their fields vibrate/wiggle more, producing a thrust.

If it is potentially as good as it seems to sound, then cycling spaceships would not be needed perhaps. But they might have value anyway.

Last edited by Void (2016-11-13 08:48:10)

SpaceNut · 2016-11-16 21:24:42

kbd512 wrote:

JoshNH4H wrote:
kbd512,
I'm not going to argue with you about this, but you're wrong and I encourage you to educate yourself.
Although I agree that the theories and principles developed by Newton and Einstein are very good general explanations for a wide variety of physical phenomenon, that does not mean that everything they theorized is an immutable truth that's universally applicable. Einstein was a brilliant physicist, but even he had his limitations. IIRC, superconductivity was and is a major stumbling block which science has yet to adequately explain. I think it's a bit closed-minded to simply declare something impossible, absent any mathematical proof.
The EMDrive is either producing thrust or a good number of highly respected and accomplished scientists from China, Russia, US, and UK all can't seem to manage the setup of an experiment to measure thrust. As someone who actually believes in evidence rather than theory, I must concede that the latter explanation is possible. However, at some point the preponderance of evidence suggesting the former should be taken into account.
Rather than suggesting that I educate myself, which is a cop-out for an actual explanation as to why I'm wrong, would you ever consider sharing your knowledge so as to educate the rest of us and explain why so many names with so many years of experience behind them are all unable to execute a thrust test which produces a result in agreement with your supposition?

EMdrive is Electro-Magnetic Drive which can take 2 forms of which 1 is in the Radio Frequency range and the other is magnetic, to form a space warp around the craft with an intense field being generated. This takes either very high voltage at low direct current or at a high switching frequency to produce the RF.

This is what the earth does as explain by Einstein for space time via gravity.

kbd512 · 2016-11-17 21:01:30

SpaceNut,

I could be wrong, but I don't think there is any clear evidence that the Nassikas thruster is warping space-time. It produced more thrust than the ion engines NASA currently uses and substantially more thrust than the EMDrive thrusters for very little power input relative to either of those engines. As previously stated, a cryocooler is required to cool the device but it shouldn't require nearly as much electrical power input as the alternatives.

A device capable of propelling a probe the size of New Horizons should weigh less than 10kg, not counting the power supply. From what I've read, electrical power requirements would be measured in We, not kWe, with a continuous operational lifetime around ten years or so.

A handful of such devices could retrieve satellites from higher orbits, deliver them to an ISS clean room module for repair or refurbishment, and thus our satellite constellations could last a very long time without the requirement for complete replacement and the hundreds of millions of dollars associated with launch services could be redirected to human space exploration programs. A purpose-built device could collect space debris around Earth to provide a less hazardous orbital environment for astronauts and satellites.

Satellites could be upgraded to use miniature versions of these thrusters for attitude control. Since every kilogram of payload costs us thousands of dollars, there's a substantial incentive to eliminate as much weight associated with propulsion as is feasible. JPL could affordably launch probes to whatever target was most interesting at the time without concern for dV requirements. With transit times measured in weeks instead of years, exploration of multiple targets becomes much more feasible.

After enough experience with and confidence in the new technology is established, we can start using it for human space exploration. Mars is the most obvious first human exploration objective, but travel to any target between Mercury and Neptune is just as feasible from a propulsion and mission duration perspective.

GW Johnson · 2016-11-18 10:53:48

I think the point here is that there is as yet no agreement on the physics, much less the engineering. These things need to attention and the funding to find out. For sure.

Meanwhile, we have rockets and electric thrusters, and they are very well understood. The solar sail is not as yet as well understood, but it is there. Might as well use them all as appropriate. Could be decades or more before any of the breakthrough stuff becomes available.

That's just common sense from a rather curmudgeonly old engineer.

GW

kbd512 · 2016-11-18 17:43:05

GW,

I would double NASA's budget in a heartbeat, but nobody elected me to Congress. NASA says it doesn't have enough money to launch the number of rockets required for a Mars mission inside of the next decade or so. We're not going to do that mission with money we don't have. Apart from the many other benefits that come from a night and day general efficiency improvement, the funding aspect of this problem is the primary reason I started this thread. NASA won't get substantially more money than it already receives and the cost of the rockets isn't going to be reduced enough in the near future that the cost of a Mars mission will fall within NASA's budget limitations.

If we don't start development now, ten years down the road we'll still be waiting for a Mars mission due to lack of funding. The development costs for these new technologies is eminently reasonable in comparison to the chemical propulsion SLS rocket which still hasn't graced the pad at KSC. Do we want to pretend that NASA is going to get more money or do we want to start trying to dramatically reduce the cost of propulsion systems for space exploration?

elderflower · 2016-11-19 04:44:24

I'm with GW. Initially we will go with what we already know and have proved because this involves lower risks of delay and unforeseen failure modes.
We have waited an awfully long time for Tokamak type fusion reactors to produce more energy than we put into them, despite having a good theoretical basis and having lots of money and brainpower applied to the problem by several nations and consortia. It has always been going to take place in twenty years time. It still is!

kbd512 · 2016-11-19 14:26:59

Elderflower,

Do you and GW want to wait until 2039 to see humans land on Mars? That's the earliest feasibility date NASA currently projects using SLS, cryogenic upper stages, and ion engines. I think ten years is a reasonable amount of time to produce flight rated EMDrives and propose spending a little more money on EMDrive so we don't have to wait until 2039 to go to Mars.

If the requirement for cryogenic upper stages or ion engines to perform TMI/MOI and TEI/EOI is removed, and a flight rated EMDrive would remove that requirement entirely, then the money and mass saved enables three SLS flights to deliver everything required for the mission over two launch opportunities. The transit times and the associated microgravity and radiation exposure is cut in half. We're also well within NASA's current and projected budget at that point, so funding should be available for a Mars Descent Vehicle, Mars Ascent Vehicle, and Mars Surface Habitat.

If the superconducting EMDrive that Dr. Shawyer is presently working on merely doubles the thrust produced for the same power input, we're looking at transit times of about a month. If it performs as well as projected, then Dr. Zubrin's argument about increasing delivered payload mass being more advantageous to a mission than decreasing transit times is invalid because we can resupply or return Mars mission crews, irrespective of the orbital phasing of our planets.

The ISS lab habitat module is completely reasonable accommodations for four astronauts if the missions only require two months of total transit time. The ISS module Mars Transit Vehicle (habitat + airlock + solar arrays + propulsion) fits within the payload shroud of a Falcon Heavy. The dimensions of a realistic Mars Surface Habitat and Mars Ascent Vehicle still require SLS, so our favored space contractor's cash cow is not de-justified.

I'm going to paraphrase Dr. Zubrin here. If better propulsion makes the mission affordable, and therefore achievable, then we should use it. Using EMDrive, we don't need to fly to Mars in a gigantic Death Star spaceship or even a comparatively modest Millennium Falcon. We can go to Mars in a tuna can. Our model will be somewhat larger than the Chicken of the Sea model.

GW Johnson · 2016-11-19 15:34:25

Kbd512:

Those things are experimental lab toys that not even the physicists all agree upon yet. There is no agreed-upon science, and certainly no engineering at all. 10 years is far too scant a time frame to turn such things into ready-to-apply technology. It's nearer 20 years at a minimum, and can be very much longer, like magnetic fusion (6.5 decades and still counting), and scramjet (5 decades and still counting, test flights notwithstanding).

All:

The following is something I wanted to post Friday night, but our internet service went off line. Late this afternoon (Saturday 11-19-16), service was restored. The topic is the “high costs of chemical rockets”. Yeah, it’s high, but it is no longer catastrophic.

I think maybe SLS colors the perceptions of too many people, regarding the costs of chemical rocket launch. SLS is actually an anomaly price-wise, being one of the worst long-running boondoggles I have ever seen. At least 3 incarnations so far over about 15 years, several big solid motor ground tests, and nothing has flown yet. (The Orion it can launch is another, separate boondoggle, not discussed here.)

All of the current commercial launchers are priced for delivering payload to LEO for a unit price in the close vicinity of $5-to-6M/metric ton, if flown at full capacity. Twice that if flown half capacity, etc. This isn't just Spacex, it's ULA, Ariane, Roscosmos, the Japanese, all of them. It is quite amazing what happens when there are enough contractors to constitute at least an approximation to real business competition in a competitive market.

ULA no longer offers its Delta-4 Heavy, because it never went through the logistical simplification that underlies the price reductions of the other launchers. Last I heard, it was 4 times the unit cost of the rest. On the other hand, if Spacex gets its act back together, so it can start flying Falcon Heavy, the projected all-expendable fully-loaded price for that one is projected at somewhere near $2M/metric ton to LEO. Something like factor 3 reduction for 2-3 times the deliverable weight. So bigger size really is also cheaper, all else being equal.

Now, the launch price for SLS is projected at $0.5B by NASA, and $1-to-2B by most of the rest of the launch community. It’s hard to say which version of SLS this might actually apply to (there are 3 payload sizes), but the first delivers 70 metric tons to LEO if flown full. That's just over $7M/metric ton by NASA's estimate, or something like $14-28M/ton by everybody else's estimates. That’s somewhere between a little, and a whole lot (!!!), more expensive than current launchers that push 10-20 metric tons to LEO.

If this pricing applies instead to the biggest version of SLS at 130 tons delivered to LEO, then just divide those unit prices I just gave by about two. The uncertainty is far larger than the estimating errors. But the trend is quite clear: SLS is not an inexpensive rocket, in spite of its size. It ought to be less expensive than Falcon Heavy in terms of unit price, but it is not.

Like I said, it's a boondoggle; giant-corporate welfare in action, mandated by a congress whose members are owned by those same giants. So why is any of this surprising to anyone? It shouldn't be.

And yet, when the market operates with significantly less distortion, commercial competition works. Look at the trend from the existing stable of commercial launchers and scale past Falcon Heavy into the 100-ton range. One should be expecting unit prices nearer $1M/ton, fully loaded, fully expendable. Maybe just a bit under $1M/ton, if everything pans out. And that’s fully expendable.

Musk's giant rocket might cost around $20-40M per launch in fully reusable form, based on his ticket price and passenger capacity projections, which probably won't stand the test of time. Supposedly it delivers something in the neighborhood of 300 tons to LEO, in that reusable mode. He seems to use (and me too) the payload equivalence of 1 passenger-plus-life-support to 1 ton of cargo. That's order-of-magnitude $0.1M/ton, which I don't yet find very credible, but it does illustrate the trend you get with very large sizes combined with full reusability.

My point is this: don't be fooled by the high costs associated with a government boondoggle like SLS!

Look instead at current or near-term commercial launchers. They are a bunch cheaper, at least half an order of magnitude cheaper! Maybe a full order of magnitude, if Falcon Heavy proves out as projected!

What that means is this: if you quit trying to shoot everything straight to Mars, you can do orbital assembly with current or near-term launchers, with payloads 10-20 tons, and soon 53-54 tons. There’s no rocket to wait for, you only need your spacecraft and your lander or landed packages.

That means you can still go to Mars sooner than NASA, and for around 3-10 times less cost. There’s nothing about such a mission that cannot be assembled the same way as ISS by docking, from 15 to 53 ton tinkertoys in LEO, excepting maybe the lander itself, if it is a big, reusable, single-stage thing.

It's not the launch rocket we need to develop, it's the lander. And the assembled-type spacecraft designs. And the unmanned stuff to be sent ahead, can be pushed there far more economically by the types of electric propulsion we already have, just scaled up. Power it with solar, nuclear, take your pick.

GW

kbd512 · 2016-11-19 18:48:46

GW,

The only thing that's experimental about EMDrive is pumping microwave radiation into an enclosed copper cone to generate thrust. No other components of EMDrive are experimental technologies and there are no moving parts. At the end of the day the hardware involved can be purchased from defense contractors for less money than rockets or ion engines satisfying equivalent propulsion requirements. Results matter and speculation from physicists does not.

It should take two years, not ten years, to develop flight rated hardware. However, since government contractors are involved they'll milk this project for everything it's worth instead of simply satisfying requirements, getting paid for doing so, and moving on to the next project.

A Quick Note on SLS Costs...

4 Core Stage RS-25's - $280M (actual fabrication cost from past purchases)
1 Core Stage Tank - $75M (assumes SLS propellant tank cost no more to fabricate than STS LWT propellant tanks)
2 Solid Rocket Boosters - $88M (actual fabrication cost from past purchases)
4 Upper Stage RL-10C's - $69.6M (actual contract amount from the contract NASA recently granted for 10 engines)

That's $512.6M, not including flight avionics, and that represents the true marginal cost of SLS, less facilities maintenance or development costs. SLS is the rocket NASA requires to deliver a 40t Mars Surface Habitat and fully fueled Mars Ascent Vehicle to the surface of Mars. The only way to make Mars missions affordable in the near term is to use substantially better in-space propulsion. Less expensive chemical rockets and ion engines are still outrageously expensive and the solution to that problem is not to use more of them.

Sidebar...

Conceptually, how would you assemble a fully fueled MAV?

SpaceNut · 2016-11-19 20:22:43

So we have some very poor contract writers on the Nasa side that like paying the big bucks to those old tried and true contractors that they trust and they are laughing all the way to the bank on SLS saying thanks Nasa....

Since its good for lifting 70 mT to orbit and 131 mT based on configuration then we should be using it just for that purpose rather than trying to launch manned ships with it....

With the EMdrive pumping in microwave radiation this is exciting any molecule of hydrogen, oxygen and water due to the frequecy just like cooking your food. Which means its not with out fuel to make it work its just real small what might be in the chamber when they fire it up....

It's official: NASA's peer-reviewed EM Drive paper has finally been published

http://arc.aiaa.org/doi/10.2514/1.B36120

EM Drive generates force 1.2 millinewtons per kilowatt of thrust in a vacuum
Hall thruster generates force of 60 millinewtons per kilowatt

GW Johnson · 2016-11-20 11:04:44

I looked at the two links Spacenut provided. I see nothing to suggest it will be less than 20 years before this EM drive thing might be read-to-apply. I have watched a lot of technology mature during the course of my professional engineering life, some of it in my own working projects. Once it's ready to apply, it might well be a game-changer. But not at 1 milli-N per KW. It'll take years to grow that ratio to practicality.

We already have working Hall thrusters at 10 times less power per Newton of thrust. Those are ready to apply, and at 4000-5000 sec of Isp, the propellant weight simply isn't objectionable, while the power supply weight is! The EM thruster makes the power supply weight problem 10 times worse! Power supply weight adds directly to vehicle dry weight. I'd just rather use the Hall thruster and go right now. But 4 months spiraling out is too slow a getaway for a manned craft. We need to reduce radiation and microgravity exposures.

As for how I'd use existing rockets to send a 40 ton habitat and a separate multi-ton Mars ascent vehicle to Mars, I probably wouldn't do it that way at all. That entire architecture is an artifact of being wedded to a giant launch rocket and straight shots to direct Mars entry. The rocket payload capacity drives the entire mission architecture, and I am surprised few others can see that. It's not just a box in which we think, it's a bloody straitjacket. That's how you send a small unmanned probe, not a practical two-way trip.

If I did go that way, I'd dock together in LEO a habitat module or two, add engines and landing gear, add heat shielding, and added docked propellant tanks and a departure stage. Then I'd shoot it to Mars from LEO. Same for the MAV.

Except that I wouldn't do it that way! Not at all! There's less risk and less new hardware to develop if you shoot stuff from LEO to LMO. That's the orbital transport and separate lander approach, something entirely different from all the other plans, including Zubrin's. Lots of stuff can be sent there with Hall thrusters, too. Such as the landers, the return propellant, and any extra lander propellant.

Only the men need ride faster with chemical rocketry. And I'd spin their orbit-to-orbit transport for artificial gravity, which makes life support design much easier, as well as greatly improving crew health.

Then use a big single-stage reusable lander, that doubles as the habitat and the ascent vehicle. You can do that at very reasonable mass ratios even with lowest-performing NTO-MMH storable propellants, if you descend and ascend only to and from LMO. The total delta-vee for the two way trip is only a skosh over 5 km/sec. At only 300 sec Isp your exhaust velocity is pretty close to 3 km/sec! You have room for 15-20% inert weight fractions (for equipment and reusability-robustness), with 3+% payload fraction.

It gets better using LOX-LCH4. With surface propellant manfacture, you can add more surface-to-surface suborbital hops to even more sites in that big lander. NO other mission plan has THAT capability! Not one that I have ever seen at all.

And if it's reusable, and you send the extra propellants for this, you can land and evaluate multiple sites while you are there waiting for the orbits to be right for the trip home. NO other plan I have ever seen, since 1956, has THAT capability!

There's nothing about my orbit-to-orbit plan that couldn't have been done 10 years ago! We had the Hall thrusters, and we had the cheaper commercial rockets, and we had the 15 tons to LEO capability. We also had the experience building big things by docking modules in orbit. And we already knew we had to address microgravity and radiation. We could have gone then.

Sorry, I just don't buy the need for an SLS, or for the need to direct-land a bunch of things at one site (a huge single-point failure mode compounded by doing it multiple times). Further, landing at only one site is inherently tantamount to nothing but an Apollo flag-and-footprints stunt again!

No two sites on Mars are going to prove to be alike, anymore than they are here. Unlike the moon, this is difficult and expensive enough that we don't need to be doing stunts anymore.

GW

Last edited by GW Johnson (2016-11-20 11:33:20)

elderflower · 2016-11-20 12:07:13

I would agree GW, but I see power as the limiting factor here. If you are going for local fuel making the huge array of solar panels, or the nuclear reactor, required to feed the fuel production plant, are not going to be easily moved around. As I see it this would make a central base necessary. The fuel provided by this central facility will enable hoppers to be used to give mobility. If you don't give the crew mobility you wont get much exploration for your investment: it will just be a long distance, long duration Apollo mission.
Earth return vehicle could be left in LMO and an additional stage could be fitted to the hoppers (actually the hoppers would be fitted to the unfuelled ascent stages first, to reduce risk of a large bang) to allow crew ascent. Then the hoppers can be left in LMO ready for the next mission.
With hoppers you might get to see a radius of several hundred kilometres from your base. That would be a lot of coverage for a crew of, say, eight with a few months on Mars.

Last edited by elderflower (2016-11-20 12:20:38)

kbd512 · 2016-11-20 13:41:47

GW,

The thrust produced did not scale linearly with power input. A 100kW power input is expected to produce 1250N. If testing repeatedly produces that expected result, then there is no reasonable alternative on a cost basis alone. The 100kW CWM-100L magnetrons weighs 6.8kg and cost between $7K and $8K, dependent upon the distributor. A 40kW MegaFlex array is 10M in diameter and 4 arrays would weigh approximately 1,440kg, not including the power conversion system. I think 1,600kg is a pretty generous mass budget for a complete power and propulsion system. EagleWorks is currently using a 1.2kW magnetron to check their model predictions. That said, someone needs to give them the measly $8K for the CWM-100L.

The X3 nested hall thruster weighs 170kg and is expected to produce 15N of thrust using 200kWe of input power. The thruster uses Xenon for fuel, which costs as much as Gold on a per kg basis, and it requires multiple tons of fuel to deliver payloads useful for a human exploration of Mars. The 4000s to 5000s Isp's you quoted produce thrust levels on par with EMDrive. The thrust goes down as Isp goes up. The higher thrust levels quoted for ion engines are in the 2000s range. Although far superior to chemical propellants for the intended use, fuel consumption is an obvious problem at the 15N thrust level.

GW Johnson · 2016-11-20 16:14:16

I don't know anything about electric propulsion except what I read. That topic is way far outside what I personally know. But I do know a whole lot about what it really takes, and how long it takes, to mature a new technology into something being ready to apply. That is precisely what I used to do for a living, from 1975 to 1994.

All I know is that newtons of thrust against dozens to hundreds of tons of vehicle weight is months to spiral-out to escape speed. You simply cannot send men that way. They must fly at impulsive delta-vees.

We can do months in space, years are questionable but probably do-able, given space in which to live, life support, radiation shielding, and artificial gravity near 1 full gee. Denying that is insanity.

I do not trust lab results from physics majors. 99% of that stuff proved to be wrong in what I did for a living, when I was an industry engineer. Sorry if that's unpopular or unpalatable, but it is my life experience. I also have learned since about 1986 not to trust anything I hear from NASA, excepting maybe what I hear from JPL, and not even all of that.

I should have learned that lesson in 1967, from the Apollo 1 fire, but I was always the optimist and wanted to trust "authorities". Not any more! I have heard too much bullshit in the decades since, about scramjet, Challenger, Columbia, spacesuits, and combined-cycle engines to trust NASA about anything anymore.

I noticed no one has said a word about how launch vehicles are the straitjacket within which all these Mars mission architectures are devised. I challenge all of you to prove me wrong about that, including Zubrin himself. Like him, I am a PhD engineer, with lots of real industry experience. He was nuclear, I was actually rocket/ramjet. I may actually know more practical things than he does, for Mars trips.

GW

kbd512 · 2016-11-22 01:11:02

GW,

The experimentation either bears the results required for use as propulsion or it doesn't. I think the test with the 100kW input power level should be conducted to determine whether or not it indeed generates 1250N of thrust. If it does, then we have our new electric RL-10.

LEO to GEO with 2.5kN thrust EMDrive:
a = F / m
a = 2500N / 22000kg
a = .1136m/s^2

4,058m/s / .1136m/s^2 = 35,722s = 9hrs 55min

Solar panels can only produce power when they're facing the sun, so escape velocity can be achieved in approximately one day for a 22t spacecraft with 2.5kN of thrust. The crew will have to stay in the radiation shelter (sleeping quarters) for a day during spiral out to mitigate radiation effects.

MegaFlex can provide the 200kWe input power required for the one month transit time. The Red Dragon lander, inflatable MTV, and solar arrays would fit within a slightly modified payload shroud. The payload shroud must be shorter. The modification is required to support the weight of Red Dragon riding atop the stowed MTV inside the payload shroud.

An expendable Falcon 9 is required to deliver the MTV and Red Dragon to LEO. There is no advantage to higher initial orbits since successful deployment of the solar panels is required before a mission begins. It's better for solar panel deployment to fail in LEO so the astronauts can return to Earth or ISS if that operation is unsuccessful. Alternatively, one Falcon 9 could deliver the MTV, less consumables, to ISS for checkout and another Falcon 9 could deliver the Mars mission crew and consumables after the ISS crew determines that the MTV is ready. ISS crew replacement and cargo delivery should be aligned to support Mars missions and lunar training missions.

elderflower · 2016-11-22 13:51:21

Nuclear thermal and nuclear electric rockets are feasible and designs were developed. Both could offer significant improvements. I do think we need to consider them again. They wouldn't take 20 years.

kbd512 · 2016-11-22 17:08:56

Elderflower,

I'm not opposed to development of NTR's, but if EMDrive works as well as EagleWorks projects it to work, there won't be much point for in-space propulsion. A flight rated NTR would require at least another ten years of development effort with adequate funding. It's a billion dollar per year program. Unfortunately, SLS and Orion have decimated NASA's advanced propulsion technology budget. NASA doesn't even know how to make the fuel elements from the NERVA program because the documentation was lost.

The Isp of solid core NTR's is only about 1000s in the pebble bed reactors. That's substantially better than LOX/LH2, but then you still have to store and cool a substantial volume of LH2 for in-space propulsion. If you intend to reuse the NTR, then you have to refuel in orbit. I think NTR's would provide the most utility as RS-25 replacements. A reactor capable of producing thrust levels equivalent to Timberwind 250 could deliver 100t to orbit in a much smaller rocket than SLS using the same SRB's from the STS program.

If we actually committed to space nuclear propulsion for super heavy lift vehicles, the launch rate could be increased to as many as six flights per year. Special handling procedures would be required for the NTR's once flown, but the facilities required would necessarily be smaller and involve far fewer personnel. Apart from irrational fear, that's a major reason why nuclear propulsion will never be implemented.

Edit:

I calculated what two Titan IV-B Hercules USRM 15's combined with a single 2.35MN NTR could deliver to LEO (185 x 185 km, 45 deg, from KSC) using a LWT STS LH2 tank with full propellant load and inter-tank support structure to support the weight of the payload:

Hercules USRM 15:
Propellant: HTPB
Empty Mass: 52,040kg
Propellant Mass: 305,199kg
Thrust (SL): 6,846.80 kN
Isp (SL): 259s

LWT STS LH2 Tank:
Material: Al 2219
Empty Mass: 13,182kg
Propellant Mass: 235,000kg

LWT Inter-Tank Support Structure
Material: Al 2219
Mass: 5,500kg

SNTP Pebble Bed Reactor:
Propellant: LH2
Mass (Est.): 10,000kg
Thrust (Avg.): 2,350kN
Isp (SL): 780s
Isp (Vac): 1000s

Booster Stage: 610,398kg
Core Stage: 263,682kg
Payload: 100,000kg (assumed to include payload shroud; actual lift capability is 103,000kg)
GLOW: 974,080kg (with 100,000kg payload)

These figures account for drag and gravity losses and assume a 3% residual propellant mass to be fed into the reactor during shutdown for cooling and clearing. It's my understanding that the heat generated during shutdown was not enough to melt the fuel elements and the taper down thrust was more of a concern to clear propellant lines than to cool the core. Even so, I've included some residual for that purpose.

The above example does not account for the fact that you can't attach Hercules USRM's to a STS ET. Actual lift capability with 2 APCP burning STS SRM's and 3% residual for cooling and clearing is 108,000kg. GLOW is 1,551,682kg with a 108,000kg payload. A composite LH2 tank, assumed to weigh 2/3 of what hard alloy weighs, will improve lift capability to nearly 113,000kg. A composite core stage tank combined with composite casing ATK Dark Night SRM's easily achieves the 130,000kg lift capability goal for Block IIB cargo without an upper stage. The boosters are assumed to produce the same 12MN of thrust and retain STS SRM dimensions and propellant mass. The composite casings are presumed to weigh 2/3 of what the steel casings weighed.

Compared to STS and SLS, GLOW is substantially reduced and no development of 5 segment SRM's or an upper stage is required. If we'd spent ten years and $10B on the NTR, we'd already have a flight rated SHLV with the exact same performance that SLS may one day deliver if it isn't cancelled before then. A LH2-fed NTR dramatically improves lift capability in conjunction with the other STS technologies currently in use.

For anyone who is wondering, the NTR uses technology that was developed two decades ago. The amount of time and money squandered by NASA screwing around with various chemical rocket engined heavy lift launch vehicles is tens of billions of dollars. So far, no results. The one thing I can say about our nuclear programs is that more often than not, those programs produce results.

Edit: I made a mistake in my payload projections. The 235,000 number is the number of pounds of LH2 contained in the STS ET tank, not the number of kilograms contained. I will re-work the numbers with the correct numbers.

Last edited by kbd512 (2016-11-26 13:49:38)

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