Air Force Funds Both AR1 and BE-4 Rocket Engine Development to Replace ULA’s Russian RD-180

BE-4 methane engine components undergo hot fire test at the Bezos west Texas test site. Photo Credit Blue Origin
BE-4 methane engine components undergo hot-fire test at the Bezos West Texas test site. Photo Credit: Blue Origin

The U.S. Air Force (USAF) decision to continue funding both the Aerojet Rocketdyne AR1 and the Blue Origin BE-4 engines will end United Launch Alliance (ULA) dependance on the Russian RD-180 for the Atlas-V rocket and new Vulcan launch vehicle set for first flight about 2020. The move will also provide new American-built propulsion options for future Orbital ATK Antares and SpaceX Falcon launchers and other future competitors too, says the USAF.

According to Aerojet Rocketdyne, the total AR1 agreement is valued at $804 million, with USAF investing two-thirds of the funding required to complete development of the AR1 engine by 2019. The Air Force intends to initially obligate $115.3 million with Aerojet Rocketdyne and ULA contributing $57.7 million.

In a separate action the Air Force also awarded ULA a $46.6 million contract to develop prototypes of its liquid oxygen/liquid natural gas (LNG) Blue Origin BE-4 booster engine and its BE-3 liquid oxygen/liquid hydrogen Advanced Cryogenic Evolved (ACES) upper-stage engine, according to the contract announcement.

Aerojet Rocketdyne graphic shows the twin nozzle design of the AR1 liquid oxygen / kerosene rocket engine with 500,000 lb. thrust. Photo Credit Aerojet Rocketdyne.
Aerojet Rocketdyne graphic shows the twin nozzle design of the AR1 liquid oxygen / kerosene rocket engine with 500,000 lb. thrust. Photo Credit: Aerojet Rocketdyne.

“Having two or more domestic, commercially viable launch providers that also meet national security space requirements continues to be our end goal,” said Lt. Gen. Samuel Greaves, the Air Force’s Program Executive Officer for Space. Greaves is also the Commander of the Air Force Space and Missile Systems Center (SMC) at Los Angeles Air Force Base that awarded the contracts.

“These innovative public-private partnerships with industry [for development of] their rocket propulsion systems are a key part of the Evolved Expendable Launch Vehicle (EELV) acquisition strategy to assure access to space and address the urgent need to transition away from ‘strategic foreign reliance’” (also known as the former Soviet Union).

Although ULA favors the BE-4 over the AR1 for the new Vulcan, the AR1 could easily retrofit Atlas-Vs.

Although all U.S. parties praise the Russian RD-180 engine performance and the talented Energomash engineers that made it possible, the move is especially critical at a time when distrust between the U.S. and Russia is deepening over Russia’s increased direct military challenges to the U.S., along with its invasion of the Crimea and its support of Syrian dictator Bashar al Assad.

The AR1 liquid oxygen/kerosene engine will have 500,000 lb. liftoff thrust, while the liquid oxygen/liquid natural gas (LNG) powered BE-4 is expected to have 550,000 lb. thrust.

The primary constituent of LNG is liquid methane, but Blue Origin now prefers use of LNG as the term used to describe the BE-4’s engine fuel.

Although there are tiny chemistry differences between LNG and liquid methane, the switch is more likely based on perceived public relations benefits from use of the word “natural” than performance factors. LNG is actually less pure than liquid methane, according to the fossil fuel websites and In addition to being “natural” LNG is also one the most polluting fuels there is, said the two fossil fuel websites.

Both of these rocket propulsion systems are designed for use on ULA’s Vulcan launch vehicle. The BE-4 is being developed by Blue Origin under Amazon founder Jeff Bezos as ULA’s preferred engine for the Vulcan, with the AR1 as a backup development.

“This award from the U.S. government demonstrates its support of AR1 and recognizes the priority of assured access to space for our critical national security assets,” said Eileen Drake, CEO and President of Aerojet Rocketdyne.

She declined to mention that as of now ULA prefers the BE-4 competitor over the AR1 for the Vulcan, but does note that the AR1 would be the engine of choice to reengine the Atlas-V.

“The AR1 engine is the option with the least technical risk that allows the United States to quickly and efficiently transition off its use of Russian-supplied engines currently used on the Atlas V launch vehicle,” Drake said.

The work is expected to be completed no later than Dec. 31, 2019. The total potential government investment, including all options, is $536 million. The total potential investment by Aerojet Rocketdyne and its partners, including all options, is $268 million.

“AR1 will return the United States to the forefront of kerosene rocket propulsion technology,” added Drake.

“We are incorporating the latest advances in modern manufacturing, while capitalizing on our rich knowledge of rocket engines to produce a new, state-of-the-art engine.”

The AR1 uses an advanced oxidizer-rich staged combustion engine cycle and will be available for commercial sale to any U.S. launch provider. AR1 will be the nation’s first domestically produced oxidizer-rich staged combustion kerosene engine.

“ULA is fully committed to transitioning as quickly and affordably as possible to a domestic engine,” said ULA President and CEO Tory Bruno. “Our supplier, Aerojet Rocketdyne, is moving us toward one of two viable options with the excellent progress on the AR1 engine development.”

Because of each company’s strong commitment to ending reliance of the Russian RD-180 engine on the Atlas V, Aerojet Rocketdyne and ULA have been investing in AR1 ahead of a public-private partnership agreement.

Aerojet Rocketdyne recently completed hot-fire testing of a single-element main injector for the AR1 rocket engine that was completely built using Additive Manufacturing. Photo Credit Aerojet Rocketdyne
Aerojet Rocketdyne recently completed hot-fire testing of a single-element main injector for the AR1 rocket engine that was completely built using Additive Manufacturing. Photo Credit: Aerojet Rocketdyne

The USAF, The Aerospace Corporation, NASA, and other government and industry experts have been kept apprised of progress on the AR1 since its inception. Most recently, Aerojet Rocketdyne held a major design review for the AR1 program with all stakeholders. The AR1 passed with flying colors, allowing the team to proceed with design implementation. Drake confirmed that “the AR1 remains on track for a flight-qualified engine delivery in 2019, which will fly in 2020.”

The AR1 also will be an affordable propulsion solution, enabling U.S. launch vehicle providers to be more competitive in the world marketplace. Low production costs will be realized by incorporating the latest manufacturing technologies such as additive manufacturing (3-D printing), white light inspection, and low-cost brazing and forming—all of which have recently been proven on other Aerojet Rocketdyne rocket engine programs. It is being priced at $20-25 million per engine.

ULA said its investment in Blue Origin engine development will be about $135 million, while Air Force contributions will approach $202 million. The total private investment by Amazon founder Jeff Bezos to the Blue Orgin project is even more sizable but proprietary.

Aerojet Rocketdyne noted that Dynetics of Huntsville, Ala., will remain a key partner in development of the AR1.

“Our collaboration with Dynetics in developing key AR1 components is an essential element to having a certified engine in 2019,” said Jim Simpson, senior vice president of Strategy and Business Development at Aerojet Rocketdyne.

Dynetics has been an integral member of the AR1 development team over the last 18 months and, with this award, that cooperation will increase, said Simpson.

Under a Teaming Agreement, Dynetics will supply elements of the AR1 engine’s main propulsion system, the ignition system, and ground support equipment, as well as provide analysis support to critical engine designs.

“We are proud to be able to use Dynetics proven hardware fabrication capabilities and engineering expertise to join Aerojet Rocketdyne in this important endeavor”, said Steve Cook, vice president for Corporate Development at Dynetics.

“Our large-scale manufacturing capabilities and extensive aerospace systems expertise, combined with Aerojet Rocketdyne’s leading rocket engine technology, offer a fast and low risk way to end U.S. reliance on Russian space launch propulsion systems.”

Aerojet Rocketdyne and Dynetics have been collaborating on large engine programs for the past three years, he said.

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  1. “In addition to being “natural” LNG is also one the most polluting fuels there is, said the two fossil fuel websites.”

    An interesting assertion. Question is “most polluting” as compared to what?

    Any one who believes that methane based LNG burns dirtier than kerosene based fuels only needs to go to maintenance depots for buses run on the two fuel types and compare the environments (watch the workers cleaning up after shift)to divest themselves of that misconception.

    • n expert report questioning the Air Force’s decision to replace Russian-built rocket engines with domestic rocket engines could explain Jeff Bezos’s sudden willingness to speak more openly about his rocket company. This morning, The Seattle Times and The New York Times each had stories about Jeff Bezos’s Blue Origin company. It was the first time Bezos had opened up the Kent-based rocket company to reporters and talked about his effort to develop a new generation of rockets and rocket engines. The new openness could be related to a report published in the Wall Street Journal three days ago. The report referenced an independent panel that reportedly concluded last year that the Air Force’s effort to replace the Atlas V rocket, which uses a Russian-built rocket engine, with a new generation of rockets using domestic engines was “too risky and likely will prove overly expensive.” The Journal article points out that these arguments “threaten to damaged United Launch Alliance LLC, the military’s premier satellite-launch provider.” United Launch, a joint venture between Boeing and Lockheed, has proposed the development of a new rocket called “Vulcan” that would use one of two domestic rocket engines currently under development, one of which is by Blue Origin.

  2. Methane as “most polluting” is based on what it does in the upper atmosphere Joe.

    From wiki: “it traps 29 times more heat per mass unit than carbon dioxide and 32 times the effect when accounted for aerosol interactions.[2]) Global methane levels, had risen to 1800 parts per billion (ppb) by 2011, an increase by a factor of 2.5 since pre-industrial times, from 722 ppb, the highest value in at least 800,000 years.[3]”

    “Methane has a large effect (100 times as strong as carbon dioxide) for a brief period (having a half-life of 7 years in the atmosphere[7][verification needed]), whereas carbon dioxide has a small effect for a long period (over 100 years).”

    It is the methane that escapes into the atmosphere, about half of which comes from natural sources, that is the problem, not the Methane that is burned for energy.

    As a rocket fuel it has a higher Isp than kerosene and is easier to store than hydrogen. It also has some of the disadvantages of hydrogen- it requires a more powerful and expensive turbompump and a larger fuel tank. There is no free lunch.

    In my view the most important characteristic is that lunar ice will most likely have volatiles facilitating methane production on the Moon. Being easier to store and transfer than hydrogen this makes it the best candidate for use in a cislunar infrastructure.

    • Yes I am aware to the anthropogenic global climate change arguments, but as you say:

      “It is the methane that escapes into the atmosphere, about half of which comes from natural sources, that is the problem, not the Methane that is burned for energy.”

      A major source of the “methane that escapes into the atmosphere” comes from cow flatulence, leading some environmentalist to demand the outlawing of the eating of red meat or even milk and cheese.

      Whatever you think of that issue for the relative amount of “pollution” from methane based LNG rockets to become significant would require the launch rate to become so large that space advocates can only dream of it.

        • I would add I find it disconcerting that so much money will be spent on such a relatively low thrust engine: relative to the likes of the mighty F-1A at 1.8 million pounds of thrust. If we are going to build new engines then I strongly believe they should be made more and more powerful with each iteration.

          So I am not so excited about these new engines- they do not measurably improve the situation concerning hardware for Human Space Flight Beyond Earth Orbit (HSF-BEO).

          • I have read in a few places that the new Methane/LOX (or LNG/LOX) engines being developed by SpaceX and BO are ~500,000 lb thrust because that gives a more optimal thrust to weight ratio (and the same ISP, if I understand correctly).

            This would mean that a single 1.5 million lb-thrust engine would weight more than 3 500,000 lb thrust engines. (including pipes and pumps, etc)

            • That seems counter-intuitive. I can’t imagine a large number of smaller engines weighing less than a single larger one. Not saying it is not true- just extremely skeptical.

              • One F-1 engine produces about 1.5 million lbf at sea level.

                One Merlin 1D engine produces about 170,000 lbf at sea level.

                Nine Merlin 1D engines produce 1.53 million lbf at sea level.

                One F-1 engine weighs about 18,500 pounds.
                One Merlin 1D engine is about 1,030 pounds.
                Nine Merlin 1D engines weigh about 9,270 pounds.

                Approximately the same thrust at seal level for almost exactly half the weight.

                • How much of that gain is the half century between development, and how much to the natural advantage here.

                  • With a more modern engine, the RD-180, produces 860,000 lbf thrust at sea level, and the dry weight is 12,000 pounds.

                    Five Merlin 1D engines produce 850,000 lbf thrust at sea level, with a combined dry weight of 5,150 pounds.

                    • That is a poor comparison though. The RD-180 is a much more complicated engine (full-flow staged combustion vs gas generator)

                      To get apples to apples you would need 2 different engines of about the same age (preferably modern), with the same fuel/oxidizer, designed for the same flight regime (sea level vs vacuum), using the same cycle (preferably staged combustion as that is what the new ones will be), etc…

                      Finding a suitable pair of engines may be impossible. We may just have to wait for the new engines to be completed…

                      Unless one is involved in the actual development of one of these engines, it’s going to be hard to prove one way or the other.

                      Intuitively bigger engines should be more efficient mass/weight -wise.

                    • Hi Ben.

                      It’s true that rocket engines are so different that it’s difficult to make any direct comparisons. To make things as simple as possible, use as few variables as possible. It does oversimplify the case, but does make the analysis less complex. I did deliberately choose RP-1 / LOX engines to keep them similar.

                      In this case, the question is whether a single large engine weighs less than a cluster of smaller engines producing the same thrust. I think that question has been answered: the larger engine weighs more by about half.

                    • Try comparing to 60s engines if you are going to use the F1 and you will find considerably less variation. The 70k engine of the A4/V2 had a T/W of 28 if you are going to ignore differences in vintage.

                    • If the answer is so clear-cut, that smaller is more efficient, then why are these companies making 500000 lb thrust engines?

                      The Merlin 1D is a 170000 lb thrust engine. Surely it is more weight efficient than a 500000 lb thrust engine? And it is already developed…

                      You are cherry picking to support your point.

                      Yes the Merlin 1D is impressive. No it doesn’t prove your point.

                      engine from 1974 (based on engine dev in 1950s)
                      Weight: 2,264 lbs
                      Thrust: 218,000 lbs
                      T/W = 96.3

                      engine dev in late 1950s
                      T/W = 94.1

                      engine dev 1954-1957
                      Weight: 2,620 lbs
                      Thrust: 180,000 lbs
                      T/W = 68.7

                      Merlin 1C
                      engine dev mid ’00s
                      Weight: 1380lbs
                      Thrust: 94,000 lbs
                      T/W = 68.1 (or 96 according to wiki)

                      Merlin 1D
                      engine developed from Merlin 1C
                      Weight: 1,030 lbs
                      Thrust: 170,000 lbs
                      T/W = 165 (or 180 according to wiki)

                    • Hi Ben,

                      Generally, larger engines make rocket design simpler, there’s fewer fuel lines and less plumbing that needs go go to each engine.

                      Actually, I didn’t cherry-pick, I grabbed the F-1 and Merlin 1D as my first two choices for RP-1 / LOX rocket engines. I did the numbers to see how it would turn out. I didn’t crunch any others and take the best one.

                      Doing it again with the RD-180 seems to have given us the same result, much to my surprise.

                      The only way to know for sure is to go through a list of rocket engines and keep doing comparisons, as I see you have selected a few. I’m not surprised that there are smaller rocket engines that do not do so favorably.

                    • Fair enough.

                      The list I provided is every RP-1/LOX gas-generator engine in the list on Wikipedia. John hare mentioned another that wasn’t on that list (and is older).

                      A comparison of staged combustion engines may be more useful, but I’m not going to bother at this point.

  3. The oxidation of methane, of course, can be carbon neutral if its derived from the pyrolysis of urban garbage and rural biowaste products.

    The leakage of some methane derived from biowaste shouldn’t be a significant contributor to global warming since the biomass from landfills already produce methane gas.

    The electrolysis of water to produce hydrogen and oxygen is still the greenest way to fuel a rocket ship– if the source of the electricity is from nuclear or renewable resources.


    • Sorry Marcel but creating hydrogen from water as “green” is what is called “greenwashing.”

      The energy has to come from somewhere. You want to make solar panels then it takes factories and transportation and energy to make them. As long as the rest of the human race is striving for a western standard of living it is self-defeating. It is a vicious circle and the only solution is to get the energy from outside the environment.

      That solution is space solar power.

      Gerard K. O’Neill realized this in the 70’s and wrote about it long before climate change became an issue.

      • “You want to make solar panels then it takes factories and transportation and energy to make them.”

        That is true. The idea that ground based solar power (from many acres of solar arrays) is clean energy is kind of a shell game. If it requires more energy from conventional sources to produce the solar arrays than the solar arrays produce it would even be a net negative.

        • It is important to consider the environmental impact but there its not just about the carbon footprint of one energy source because they all have a carbon footprint. Solar panels have to be manufactured. Methane has to be mined. Kerosene has to be refined. Nothing is completely green. You have to ask yourself would you rather have methane and kerosene with their carbon footprint or solid rocket fuel chemical pollution?

          There is no other way around it. In the long term a 20-35 million pound thrust launch vehicle using twin monolithic solid rocket boosters will prove to be the only option. The environmental penalty is going to have to be paid if the far bigger pay-off of clean energy from space based solar power is going to be realized.

          • Was not attempting to compare ground based solar to space based solar, but rather ground based solar to the primary energy sources required for producing/maintaining the solar array fields.

            If the ground based solar array fields produce less energy than has to be expended from other sources to produce/maintain them, then it is a bad deal both environmentally and economically.

            • If the ground based solar array fields produce less energy than has to be expended from other sources to produce/maintain them, then it is a bad deal both environmentally and economically.

              Depending on the details of the system, its location and the assumptions made, Earth-based solar power systems have EROI (Energy Return on Investment) in the 8 to 34 range (i.e. they produce 8 to 34 times more energy during their useful life than was needed to manufacture and install them). The EROI threshold for any energy source to be economically viable is around 7 or so.

              • Interesting, have encountered widely (might even say wildly) varying estimates for both ground based solar arrays and windmill farms.

                As “they produce 8 to 34 times more energy during their useful life than was needed to manufacture and install them” is a pretty wide range and does not include maintenance over what would presumably be a very long time, would be interested in examining a source for that particular estimate.

                • Gary Church did not write that. If people are going to play these kinds of games then I guess that is it for me. NewSpace is so messed up. Disgusting.

                  What a bunch of creeps.

                  • Conway Costigan

                    You are clearly guilty of a “thought-crime” and should expect idiotic harassment and foolish attempts to embarrass you. Don’t give up.

                    “In point of fact, the 2010 NASA authorization reiterated the goals of the VSE, specifically mentioning the critical role of cislunar space, including the lunar surface. This direction was ignored by the agency, wherein it became a thought-crime to even mention any possibility of human crews going to the lunar surface.” From: ‘Stability and Instability in Space’ February 27, 2016 by Paul Spudis At:

                • have encountered widely (might even say wildly) varying estimates for both ground based solar arrays and windmill farms

                  One would expect widely varying values for something like solar based on the amount of Sun a location gets or wind depending on how windy it is. But there are also variations based on how the value is calculated.

                  would be interested in examining a source for that particular estimate

                  You could try this link (I am not endorsing the article but merely provide it for informational purposes):


          • Gary,

            for God sake. Space Solar Power plant will not work on economy scale. There is double conversion and it makes NO sense to do it.

            You have next – photon to electron to photon and back to electron. Ever did Math on this? (I did and it was not for fun it was part of project – almost 20 years ago! – was team of us!)

            On top of that problem you have next issue:

            cost of sending things up (rockets, people, people in space etc etc)
            cost of things on earth
            cost of getting everything connected
            cost to run things (will need fuel and other things to keep it in orbit )
            HUGE risk for The Kessler syndrome (this is SUPER important!)

            Is it possible to do it – current technology? YES! But it will never make sense money wise.

            It can make sense if you want to send power for let’s say military reasons or where you ignore the cost for whatever reasons.

            Let me give you a bit more data. To create 1 GW output in space, you will need around 5 km2 for Solar Collector Area + other things, so add another 500-600 m2. (minimum at best)

            ISS have size around 7500-ish m2 so can you see what type area we need to get 1 GW?

            Cost of everything is super hard to make, but I talked with people in NASA (Yes, I been there!) and they did some math (for fun) and cost was around $150-200+ billions, but that was just over 5 min talk, and quick numbers out of the head. (Ofcourse company like SPACEX could reduce cost down on this if they could relunch over and over!)

            Cost for ground system for 1 GW would be less then $3.5 billion – EASY (this also include land cost, as long its not super close to city but a desert etc)

            There enough land area on world to collect more then enough power we will need in near or distant future.

            This is not attack on you, its just facts.


            • Ivan,

              I have no desire to get into arguments/counter arguments about the feasibility of SSP’s with you, but NASA (Yes, I have been there also) has done a number of formal studies over the decades with varying results none as negative as what you present.

              My own opinion is that SSP’s will never be viable if the bulk of the material for their construction must come from Earth. Introduce the use of Lunar resources and all that can change.

              This is not to say we are ready to begin building Lunar derived SSP’s now. If that is to ever happen there is a lot of development work to be done first. Starting with a Lunar return and proof of various techniques for using Lunar resources.

              That is the reason I am also skeptical of many of the ground based solar concepts as well. Many of the economic studies are based on (lets be polite and call them) optimistic assumptions.

              • Joe,

                are you saying that ground cost for SOLAR PLANTS are not well known or what exactly? There is many solar power plants up and running and costs are very much transparent.

                The cost of solar panels is also droping like crazy.

                Price droped from around $1.3-ish a watt in 2011 to around $0.50/W in 2015 – prediction is that by 2017 we will see prices even less or around $0.30/W (this is for panels ofcourse). You would need to add all other material + labor + land + construction etc.

                There is really NO mistery regarding Grand Based Solar power plants.

       – around 0.5+ GW – cost was $2.5 billion


                • Questions:

                  (1) What percentage of current American energy usage does solar power currently supply?
                  (2) How many acres of solar arrays would be required to supply American energy needs?

                  Again this kind of back and forth could go on forever and I am not interested.

                  It is interesting to note however that you recently accused me of being arrogant and getting older because I was skeptical of SpaceX and (so you said) unwilling to accept new possibilities. Now it is I who am discussing the different ideas and you who are supporting the status quo.

                  Guess that means I am the young and humble one and you are the one who is old and arrogant.

                  Funny how things work out isn’t it.

                  • Joe,

                    it’s not about that “my” ideas are “cool” and yours “not”. I am super ready to change my mind based on math and data. It’s not that I am arrogant or old. It’s pure numbers. No emotions what so ever!

                    Do I want us to have SPACE BAD-ASS SOLAR STATIONS ? YES! But who is goin to pay for that?

                    Regarding your questions.

                    I had to look up this and I found it’s less then 1% – or more specific 0.4%


                    0.4% means, you guys (in USA) have already 20+ GW of solar plants or in this case 20 x 1 GW SPACE SOLAR POWER PLANTS but on ground.

                    You can compare other energy sources as well.

                    To be honest, biggest potentional in USA is not SOLAR it’s wind! You guys already get ten times more power from Wind compare to solar!

                    Land of area – tricky to do the math – but here is the map so you can see how much LAND would need to be used for ALL ENERGY – EARTH WISE to be generated ONLY by solar (And this is not for now, but 2030 projection)


                    You need to understand that LAND Is really not that big of a issue when it comes to solar. Moste of the solar will not be in plants, but rooftops in industrial complexes and privat houses etc.

                    For example, Germany have HIGHEST amount of solar power compare to any other country, and that number is around 40 GW-ish. To put this in perspective, Texas is 2x in size of Germany.

                    USA alone is around 27x times bigger then Germany.

                    USA is very late in SOLAR game, for example, Italy is producing about the same as USA!

                    I was suppose to work in Nuclear Power plant (Life made some decisions for me, so I went other direction), and I can get very tehnical on this subject, I am all PRO-ENERGY in any shape or form, but COST wise it will not make sense at all to create SPACE SOLAR PLANT

                    Even if we say that cost would only be 5 times of ground setup, it would still be out of reach.

                    So in numbers. We need 191,817 square miles for solar panels for 2030 power projection at 20% efficiency (THIS IS FOR WORLD – NOT JUST FOR USA)

                    Please have in mind that SOLAR PANEL efficiency – will go up. Even now, we have multiple-junction solar panels that can go 42-44%+ – but very very costly.

                    Since this is SPACE website, have in mind if we fuck up something with solar plants in space, and we make space collisions, we will end up with The Kessler syndrome (Something that guys at NASA told me to check when we talked). This is something we never really considered when we was working on project, it was beyond of scope our understanding how about space instalations. The more things in space, the more chance something will go BAD, and once collisions starts there is no way to stop domino effect and we can end up in really bad situaton where is super hard or even very risky to even lunch something in space, cause it will get hit by junk over and over at huge speeds.

                    ANOTHER THING TO CONSIDER – LAND!

                    Even if we go with SPACE SOLAR PLANT – you need to send that power down, and you will need ALOT Of land for location where microwaves are collected – here is what I have found from NASA/DOE studie.

                    I quote:

                    A reference concept from the NASA/DOE studies for an SPS is illustrated in Fig. 1. It is a 5-GW system with a large 50-km2 solar cell array in GEO that converts sunlight to electrical energy, which is then transmitted to Earth by microwaves from a 1-km diameter antenna. The microwaves are collected on the ground by a rectifying antenna

                    measuring 10 km in diameter and then converted to electrical energy that can be fed directly into the power grid on Earth. At 35 degrees latitude Fig. 1 indicates that the ground spot for the rectifying antenna warps into a 10 km by 13 km ellipse.

                    You can read the studdy here:

                    Topaz Solar power plant is using 9.5 sq mi (25 km2) – so all that LAND you plan to “save” by putting something in space is NOT GOIN TO HAPPEN

                    Again, maybe some new tech will happen, that will make all the difference, but this is not about will or “lets get it done” its really crazy to do it based on current numbers.


                  • Just some quick info.
                    Topaz Solar Farm
                    550MW of solar panels, but with 23% capacity factor generates just
                    1.1 TWh / year.

                    USA usage (as of 2013) 25451 TWh

                    Land usage of Topaz Solar Farm. they own 9.5 sq mi, but there appears to be ~7 sq mi of solar panels.

                    1.1 TWh/9.5 sq mi
                    it Will take ~ 220000 sq mi to generate entire USA demand.
                    California Area 163696 sq mi, so 1.34 * California’s area…

                    Of course there would be issues with cloudy days (if 1/3 the US is covered in clouds it doesn’t matter if it’s accounted for in the capacity factor)

                    And of course night time.

                    Since solar farms are generally placed in the best places first, additional solar farms are likely to have worse capacity factors.

                    Note: I like solar power, but I don’t think it will work as anything close to the primary power source… (space solar has already been addressed well by others)

                    • Hi Ben,

                      Great stuff. I knew it was about in that range, but the details are very educational.

                      That means there would have to be about 23,000 Topaz Solar Farm equivalents to meet American Energy needs.

                      This is over simplified, but (given reductions in efficiency due to location of many of the plants not unreasonable). At $2.5 Billion/Topaz Equivalent that would be $57.5 Trillion dollars. But Ivan would dismiss what he describes as $200 billion for a space based system (about 0.4% of the cost of a ground based system). Do not get me wrong, I think the space based system would be more expensive than Ivan projected to denigrate it, but it would still be more than competitive.

                      I also like solar power (and windmill farms for that matter) for specific uses in specific areas, but agree they will not “work as anything close to the primary power source”.

                      SSP’s as a primary power source are a wild card if Lunar resources can be used. Truth in packaging I support Lunar ISRU for a multitude of other reasons, if it leads to a practical SSP System as a primary power source that would be a great bonus.

                    • As with all energy production it is a use it or lose it until we have cracked the storage systems. Home storage is just now starting to come online which will have an effect in alternative energy like wind and solar. Wind works day or night to augment solar and if you can store excess during peak production that will bring it together.

                      Have not seen anything on industrial storage yet.

                    • “SSP’s as a primary power source are a wild card if Lunar resources can be used.”

                      Manufacturing on the moon from raw lunar materials is the only way it can work without polluting our planet into a cesspool. Launching millions of tons of solar power equipment out of Earth’s gravity well is a non-starter. Lifting that mass off the Moon and moving it through cislunar space to GEO is a small fraction and there is water ice on the moon to provide the fuel to do it.

                      The answer is automated manufacturing on the moon. The only way to do that is to build SHLVs. There is no cheap.

                    • Joe and Ben,

                      first of all, the study I have given you is by NASA, not by me, or some silly people running around saying silly things.


                      COPY PASTE from document:

                      VII. Conclusions
                      Large SPS concepts in GEO for power transfer to Earth do not appear to be practical at this time when compared
                      to current ground-based CSP systems. Even though the SPS concept has a higher end-to-end efficiency it does not
                      appear capable of outperforming the CSP system when it comes to the size and complexity of the competing


                      Regarding LAND area you need. 70% of area used for solar will be on existing infrastructure already, so no lend used/wasted ok?

                      Space Solar cant beam power to city directly, need to have collection area + exlusion zone around it, so there is LAND used up for that.

                      When it comes to POWER it self, forget solar ok? (For argument sake).

                      Right now, USA already have more then 75+ GW in Wind alone, witch is almost 4 times of solar as of today. (Europ right now have around 130 GW-ish)

                      Future will not goin to be SOLAR solar exclusive, or even Wind, or Nuclear or whatever, it will be mix of all of them.

                      Your math of cost is way wrong, for around 25+ trilions, but if you would go FULL solar alone cost would be HUGE. Solar is not goin to save us, not alone anyway.

                      Topaz Plant cost today would be almost 70-80% less cause of reduction of solar panel prices.

                      In short it goes like this

                      Earth Solar plant – cost:

                      Land + solar panels + construction + transport + people + maintenance

                      Space Solar plant – cost:

                      Land + exlusion zones around land + construction in space + transport in space + people in space + maintenance + cost to keep it in specific orbit

                      I dont wana copy paste wikipedia, but super easy layout PRO vs CON


                      Even with MORE energy generated in space (Witch is true!) after all conversion losses and what not, will not make sense.

                      One can argue, that we can maybe manufacture panels on Moon etc, but we dont even have base there, let alone to produce solar panels in first place!

                      Tech wise, can it be done, yes, yes and yes, but it makes no sense what so ever.

                      You will not save land, you will not save money, you will not generate more power compare to eart solar by the end of the day.


                    • “One can argue, that we can maybe manufacture panels on Moon etc, but we dont even have base there, let alone to produce solar panels in first place!”

                      The only reason we don’t have a base there is because NewSpace has us stuck in LEO.

                      Earth Solar Plant – cost:
                      Land + solar panels + environment footprint from building solar panels + construction + environment footprint from construction + transport + environment footprint from transport + people + environment footprint from people + maintenance + environment footprint from maintenance.

                      Space Solar Plant – cost:
                      Much less land and exclusion zone + construction in space + transport in space + people in space + maintenance in space + cost to keep us in specific orbit.

                      One trashes our planet. One does not. It is not easy. It is not cheap. It is the only way.

                    • How does NewSpace have us “stuck in LEO” any more than “OldSpace”/Non-NewSpace does?

                      Regardless of whether it is NewSpace companies doing it or not, we still need transport to/from the ISS. (and Boeing/ULA for commercial crew is hardly NewSpace, and have received ~58% of commercial crew funding to date)

                      The SLS/Orion has been well funded for years. Commercial crew/cargo have also been funded although not at the levels required to meet the desired in-service dates.

                      As far as I know the rest of NewSpace companies’ funding areeither small or not from US government sources. There are certainly plenty of Space Act agreements between NASA and NewSpace companies, but these do not cost NASA much, budget-wise.

                      The NewSpace space launch companies by-and-large seem mostly interested in getting the costs of transport to orbit cheaper. Which arguably is helpful for making any BEO mission cheaper as well.

                    • Ivan,
                      This is like so many other things that might be, dependent on assumptions. If one assumes solar power production equipment from Lunar and/or asteroid sources, all of the numbers change. The up front cost is huge, the continuing cost is relatively low compared to launch all from Earth. Once a production plant is up and operating with all the bugs worked out, it can produce power plants for decades.

                      Not easy, and not cheap, but theoretically feasible withing the next half century or less. Whether it is in fact better than alternatives is an open question though. Expected political or financial ROI will decide the issue.

                    • How does NewSpace have us “stuck in LEO”

                      Just take baby steps is the theme of the NewSpace Mob, along with thinking they can do space cheap. That is how NewSpace pushes their LEO business plan. LEO is not space. Space travel to an actual destination is properly defined as Human Space Flight Beyond Earth Orbit but NewSpace wants nothing to do with the Moon.

                      The Ayn-Rand-in-Space billionaire hobby rocket crowd does not like SHLVs with hydrogen upper stages because they dont put money into the pockets of Silicon Valley entrepreneurs. The real SHLVs that are the only way to get the automated production equipment to the moon require a state-run tax subsidized effort. The dreams of NewSpace are based on tourists in Jiffy-Pop LEO hotels. That is a dead end.

                      The ice on the Moon means there is a now a reason to go back and should be the central focus of the entire Human Space Flight community. The first project this ice enables is replacing the GEO satellite junkyard
                      with water shielded human-crewed space stations and capturing the over 100 billion dollar a year revenues of that industry. After that the path will be clear to transmit power back to earth from orbiting solar farms that receive sunlight 24 hours a day. Building those solar arrays from resources on the moon will have to be a global public works effort. There is no cheap.

                    • I wasn’t saying that NewSpace companies don’t tend to prefer tackling LEO first (after all that is what NASA pays them to do…)

                      But SpaceX at least seems pretty excited about Mars. And they seem to be working their way to some pretty big rockets too. After all the Falcon Heavy will be able to carry significantly more than a Delta IV Heavy.

                      There are asteroid/lunar resource extraction NewSpace companies as well. (Deep Space Industries and Planetary Resources, off the top of my head)

                      SpaceX is developing Methane/LOX engines because methane can be manufactured on Mars (and they don’t leave soot and they have better performance).

                      Do I think we should make a base on the moon and extract resources (water included), yes I do. But, I don’t own a company capable of doing that. And even if congress & President decide to fund such a venture, in 4/8 years it’ll probably get canceled anyway.

                      Because of this I see it as only a good thing when we have multiple relatively independent attempts to get somewhere wrt human spaceflight.

                    • NASA has substituted a LEO dog and pony show for a realistic and rational human spaceflight program.

                      Mars is a non-starter. The real show stoppers are radiation exposure on the trip there and not enough gravity to stay healthy. The first can be solved with ice from the moon but since Elon Musk got the president in his pocket and NASA cancelled Constellation there is no way to get there. The second cannot be solved. Mars is a dead end. The NewSpace infomercial just keeps the money rolling in for the billionaire playboys while NASA can take credit for this mass delusion. They are responsible for not educating the public over the last half a century. They have never made an attempt to inform the citizenry of the realities of space exploration.

                    • Hello John hare,

                      I am with you on that, as you say “next half century”. To be honest, I dont think any country right now – except CHINA – can even do such long term plans, cause of Human factor and politics all around.

                      We cant even agree on basic things on this website 🙁

                      Its just so hard to plan (not impossible) but we as humans dont work very well when it comes to things like that.

                      When it comes to ENERGY – I dont think solar or even wind is goin to be best option for us, but FUSION reactors.

                      The Germans are doin best work right now, and The Wendelstein 7-X Reactor is doin very well! (It’s experimental but working superb so far!)

                      All test so far was success and no issues what so ever.

                      Can read all about it here:

                      Reactor is called Stellarator and it was invented by Lyman Spitzer back in 1950+ ish (I would need to look up exact date)


                      They look very strange (design wise) compare to tokamaks but reason behind that is they dont require toroidal current, and we did not had enough COMPUTING power 50-30 years ago to make good simulations to create optimum design for plasma flow (that’s why it looks so strange right now)

                      Back in school days, we talked about how this design as “been there – done that – did not worked!”

                      Russians did so much better work on tokamaks in 1950+ that everyone was sure we are just 10-15+ years away from working reactors. So even USA droped everything else and focused on tokamaks. Fast forward today, and still no GOOD tokamak design

                      I recommend this two links



                    • john hare,

                      Per your posting March 4, 2016 at 3:38 pm. That is precisely the point

                      We are in complete agreement on this one.

                      I’m not sure which of us needs to change their mind. 🙂


                      Per postings by “Gary Church”. I think Conway Costigan may be correct about this one. I don’t think “Gary Church” is legit. You may be wasting your valuable time responding to a troll.

                    • 9.5 sq miles is the site size.

                      each mod. panel is 3.937′ x 1.968′ x 9,000,000 panels. Comes out to 69749860 square feet or about 1601 acres. About 2.5 sections/sq miles.

                    • “Per postings by “Gary Church”. I think Conway Costigan may be correct about this one. I don’t think “Gary Church” is legit. You may be wasting your valuable time responding to a troll.”

                      The only comments made by Conway Costigan are at the top of the page- and there are no comments being made by the real Gary Church on this page. The rest sound like me- but they are not.

                      This will be my last post as Conway Costigan and while I tried to post using my real name over on Parabolic Arc this cyberstalker is also doing this to me there. Looks like my commenting days are now over except, of course, for Dr. Spudis’ site, where he actually moderates.

                      I have repeatedly emailed the editors of this site and they are taking no action. Since any post I make is almost instantly recognizable because of my views, whoever is doing this or others will just stalk me again in the same way. Some months ago I was posting on and the trolls there starting posting comments using my name and made it uninhabitable.

                      When bullying does not work the NewSpace mob will find a way to silence any critics. Like they just silenced me.

                      Bye Joe. Good luck.

                      Gary Church

                    • Ben

                      “The NewSpace space launch companies by-and-large seem mostly interested in getting the costs of transport to orbit cheaper.”

                      “Do I think we should make a base on the moon and extract resources (water included), yes I do.”

                      Yep, and the AR1 kerolox engine can also help to reduce the “costs of transport to orbit”.

                      And the AR1 might not be limited to only being used for launches from Earth.

                      ‘Solar photothermochemical alkane reverse combustion’ By Wilaiwan Chanmanee, Mohammad Fakrul Islam, Brian H. Dennis, and Frederick M. MacDonnell in ‘Proceedings of the National Academy of Sciences’

                      “A one-step, gas-phase photothermocatalytic process for the synthesis of hydrocarbons, including liquid alkanes, aromatics, and oxygenates, with carbon numbers (Cn) up to C13,from CO2 and water is demonstrated in a flow photoreactor operating at elevated temperatures (180–200 °C) and pressures (1–6 bar) using a 5% cobalt on TiO2 catalyst
                      and under UV irradiation.”

                      Solar and nuclear power offer many options on the Moon and Mars, including the ISRU creation of hydrocarbon based propellants including the RP-1 propellant needed for the AR1.

                      Using a future version of the AR1 rocket engine to power a large Lunar Lander may be desirable.

                      If someday the Lunar Lander’s launch acceleration occurs within a tunnel and is done with an AR1 powered rocket sled, it should be quite possible to fully recycle the AR1 engine’s exhaust to make new propellant.

                      Note that the Moon’s escape velocity at 2.38 km/s is less than the 2.8 km per second velocity achieved by rocket sleds on Earth.

                      Using kerolox rocket engines for Lunar, Mars, and Ceres Landers could enable them to have relatively small and lightweight propellant tanks and a low center of gravity.

                      If a Lunar, Mars, or Ceres Lander is repeatedly used for ‘hop exploration missions’, the low center of gravity offered by the relatively dense kerolox propellant combination could be a significant safety advantage.

                      The room temperature stability and useful density of RP-1 might also make full tanks of it quite useful for Galactic Cosmic Ray, or GCR, shielding.

                    • James,

                      “If someday the Lunar Lander’s launch acceleration occurs within a tunnel and is done with an AR1 powered rocket sled, it should be quite possible to fully recycle the AR1 engine’s exhaust to make new propellant.”

                      An innovative concept. It was originated by Krafft Ehricke in the 1970’s. He was working on ideas for Lunar Industrialization and at the time the existence of large amounts of water (and other volatiles) at the Lunar Poles had not been discovered/verified. The idea was to recover hydrogen in this fashion.

                      The drawback of course (in addition to making the recovery process work) is that to build the launch tunnel would require a considerable Lunar Surface construction capability to be established first.

                    • Technological advancements may impact the economics of space, Lunar, and Earth based solar power in several ways. For example…

                      “Just one-fiftieth the thickness of a human hair, and capable of producing up to 6 watts of power per gram, these cells are so thin and light that they can be supported on the surface of a soap bubble without breaking it.”

                      From: ‘Thinnest, lightest, solar cells ever created outperform their bulky glass brethren’ By Colin Jeffrey March 1, 2016 At:

                    • James,

                      Perhaps, but a few questions should be asked:

                      (1) How much will these cells cost to manufacture?

                      (2) How much (if any) do they reduce the surface area/power ratio?

                      (3) How much (for terrestrial use) will the surrounding structural mass be to protect these cells from the surrounding environment?

  4. We can quibble on the pro’s and cons of each engine design and functionality, but the most important statement, in my opinion,is in the very first paragraph, “end the reliance on the RD-180.” That is the best news and long overdue!

  5. “The move will also provide new American-built propulsion options for future Orbital ATK Antares and SpaceX Falcon launchers and other future competitors too, says the USAF.”

    A single AR1 engine could enable an improved Delta II or some other similarly sized and economical launch vehicle.

    Three to four AR1 engines on an enlarged Orbital ATK Antares launcher that also uses the GEM-63XL boosters, that are to be used on the Vulcan launch vehicle, might be a possibility.

    Another possible launcher could be four to six AR1 engines on an enlarged Orbital ATK Antares launch vehicle that also used two very large Solid Rocket Boosters similar to those used on the SLS and thus could also offer another useful heavy lift launcher option if used with the Exploration Upper Stage (EUS) of the SLS or some other large hydrolox upper stage.

    Note: “The company said it is also throttling up spending on a new launch vehicle with substantially more lift capacity than its newly re-engined Antares rocket, with early development co-funded by the U.S. Air Force.” – From: ‘Orbital ATK believes in satellite servicing, but not rocket reusability’ By Peter B. de Selding March 2, 2016 At:

  6. Joe

    “The drawback of course (in addition to making the recovery process work) is that to build the launch tunnel would require a considerable Lunar Surface construction capability to be established first.”

    Yep, I’ve worked with a bulldozer and a front end loader. It is likely that building tunnel based rocket exhaust gas recovery systems on the Moon, Mars, and Ceres could be quite doable if the right type of equipment was available.

    Driving around in large and slow dump truck sized vehicles needed to carry adequate Galactic Cosmic Ray shielding for human transport vehicles on the Moon, Mars, and Ceres may get inefficient pretty quick. Building berm protected roads for partial GCR shielding seems like an early and useful task for colonists.

    Adding rails on the berm shielded straight roads can significantly decrease road friction and safely and dramatically increase travel ‘speed limits’ and thus reduce human GCR exposure time for both crews on long term missions and colonists.

    Putting a roof on the long and straight berm-rail-roads on the Moon, Mars, and Ceres would reduce rail thermal expansion and contraction issues and also add major GCR shielding protection for human surface rail vehicles as well as add the useful optional capability of recycling exhaust gases of various types of reusable rocket powered sled launchers.

    In short, the useful long straight railroad surface transport system logically evolves into an option for a “Krafft Ehricke” rocket exhaust gas recovery system that might reduce transportation costs across the Solar System.

    Of course someone might also eventually decide to build such a “Krafft Ehricke” ‘tunnel’ based rocket exhaust gas recovery system in space or on Phobos… Now those are two fun ideas!

    And of course, a one mile in diameter circular tunnel rail and train system could provide a safe, healthy, and useful one ‘G’ environment. I do like the comfort of long train rides!

  7. Joe
    March 5, 2016 at 4:41 pm


    Perhaps, but a few questions should be asked:”

    Actually, lots of questions need to be asked of all types of proposed solutions to various issues. The answers may change significantly as our technological tool kit evolves and improves over time.

    For solar power systems on Earth, the Moon, Mars, and Ceres or in space the durability, or effective lifespan, and maintenance requirements might also be significant cost and safety drivers.

  8. “The AR1 engine is the option with the least technical risk that allows the United States to quickly and efficiently transition off its use of Russian-supplied engines currently used on the Atlas V launch vehicle,” Drake said.

    I am less sure of that. It seems unlikely the AR-1 is a direct drop in replacement for the RD-180. The RD-180 is not only a Oxygen Rich Staged Combustion cycle but at the outer edge of what is materially possible with with an extremely high chamber pressure of 3,700 psi and turbo pump outlet pressures of more than 8,000 psi. It seems highly unlikely you can make such an engine reusable or not pose severe technical challenge to duplicate.

    What is more likely is the AR-1 is an engine with lower performance than the RD-180 and would require significant changes to the launch vehicle to meet the required payload capability.

    Hopefully the AR-1 finds a rocket to fly in. ULA’s decision to use the BE-4 has merit and probably will be the least expensive and most reliable engine.

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