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Return to the Moon Space Tug

Return to the Moon Space Tug

The idea of an unmanned, solar electric powered, reusable space tug for hauling payloads around the solar system like an ocean-going tug that moves barges and oil drilling platforms around the world, has been around for a long time. What has given this idea staying power over the years is its potential to reduce cost by significantly reducing the amount of propellant required to move a payload to its desired destination. Less propellant means less cost. In the case of a Return to the Moon space tug, it will eliminate the need to launch a large chemical powered upper stage into Earth orbit every time we need to send a payload to the Moon. The disadvantage of the solar electric space tug concept is that it is slow. What takes 3 to 5 days with a chemical powered upper stage takes 8 to 10 months with a solar electric space tug. This is too slow for people, but perfect for moving non-time sensitive payloads like air, food, water, propellant, spare parts, habitat modules, lunar landers, pressurized rovers for exploring the Moon, propellant making equipment and so on. In short, a Return to the Moon space tug will be perfect for moving just about everything except people and it will do that for a fraction of the cost of a chemical powered upper stage.

So where do we get one?

It turns out we already have one. The Power and Propulsion Element (PPE) for the planned Gateway Space Station was originally designed as the solar electric propulsion system for the Asteroid Redirect Mission. Its job was to go out and capture a 20-ton asteroid and bring it back to lunar orbit. When the Asteroid Redirect Mission was canceled, this power and propulsion module was repurposed to provide power and propulsion for the Gateway Space Station in its L2 Halo orbit. This same power and propulsion module will also be perfect as an unmanned space tug for hauling cargo from Earth orbit out to lunar orbit. Considering the amount of equipment, supplies, and propellant, that will need to be hauled out to the Moon for building a lunar base, we will need a small fleet of these space tugs and they will save the Return to the Moon program huge amounts of money.

For example, a fully loaded Pressurized Cargo Module from a Cygnus cargo spacecraft has a mass of 5,300 kg when it arrives at the International Space Station (1,800 kg for the cargo module and 3,500 kg of cargo). If storable propellant is being shipped to the lunar orbit space station that will be 5,000 kg of propellant and 300 kg for the tanks that hold it. When either of these payload modules are attached to a PPE space tug, it then becomes possible to move that cargo out to lunar orbit for a small fraction of the cost of a chemical powered upper stage. The 4,000 kg space tug loaded with 3,000 kg of propellant and 5,300 kg of payload, will take approximately 300 days to go from the International Space Station to low lunar orbit. The advantage of this is that the space tug will use only 1,800 kg of propellant to do this. That is a huge saving. Flying without payload, the space tug will then be able to return to the International Space Station in approximately 127 days using an additional 750 kg of propellant. That comes out to .48 kg of propellant for every kilogram of payload delivered to lunar orbit. Using an expendable chemical powered upper stage like the ones described in Return to the Moon Launch Vehicles, will require 3.4 kg of propellant and hardware for every kilogram of payload delivered. That is 7 times as much mass that needs to be lifted to Earth orbit and then thrown away in order to deliver a payload to lunar orbit. Based on this difference, the reduced cost of using a solar electric space tug should be obvious.

Moon Base. Building a base on the Moon for mining lunar water is a huge logistics problem. It will require a steady stream of equipment and supplies to get it going. It will also need a way of delivering the water and propellant it produces to where it is needed. All of this movement of goods needs to be done as cost-effectively as possible. This is what the Return to the Moon space tug is for. To use this type of vehicle for hauling cargo out to a lunar orbiting space station on a regularly scheduled basis will require a small fleet of space tugs flying all the time. Assuming a round trip travel time of 450 days, 5 tugs will have 90 days between flights, 10 tugs will have 45 days, and 15 tugs will have 30 days. Larger payloads will require multiple space tugs to make the journey in the same amount of time. This is the supply pipeline that will allow us to build a lunar base and start mining the Moon for water so we can go to Mars. This is the pipeline that will make the Return to the Moon program sustainable so it can be a Return to Stay program.

Having a fleet of space tugs is not necessary for meeting the 2024 deadline for returning to the Moon. Yet since we already have a space tug it makes sense to start using this technology as soon as possible to reduce the cost of hauling payloads to the Moon. Savings, that can be used to help build the lunar base and to make improvements to other parts of the transportation system to further reduce transportation costs. As previously stated, Returning to the Moon to Stay means designing for minimum transportation cost. Not paying attention to this will make the Return to the Moon program into another government boondoggle that will not last.

Propellant. The ion propulsion system on the space tug uses xenon for propellant. This is a somewhat rare and expensive gas. As the number of space tugs increases, obtaining sufficient quantities of xenon for them could become an issue. Therefore, sometime in the future, it will be necessary to change the propulsion systems on the space tugs to one that uses argon for propellant. Since argon is the third-most abundant gas in the Earth’s atmosphere, supply will not be an issue. One possible propulsion system for this change is called VASIMR, which stands for Variable Specific Impulse Magnetoplasma Rocket. This propulsion system has the additional advantage of having almost twice the specific impulse of the current ion propulsion system which will further reduce the cost of transportation. It is also important to keep in mind how valuable these space tugs will be for moving a space station, landers, and return propellant to Mars orbit prior to the first human landing on Mars.

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It is time to step into the universe of unlimited possibilities and create the most wondrous future imaginable.

It is time to Open the High Frontier.

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Note: For those of you who are new to this website, this site is about making spaceflight affordable to everyone so we can finally start building the most incredible civilization the world has ever seen. A civilization that will include planets, asteroids, moons, space-based industries, and space colonies throughout the solar system. For those of you who are fans of space exploration but are new to the subject, the best way to read this site is to start at the beginning and read through to the most current article. If you are already familiar with the subject then feel free to jump around.

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Return to the Moon Lunar Landers

Return to the Moon Lunar Landers (low lunar orbit)

The initial Return to the Moon lunar landers that will operate from the low lunar orbit space station will consist of 3 different vehicles, a 2-person crewed vehicle that will look like the ascent stage of the lunar lander used in the Apollo program but with landing gear legs added,

a cargo lander that will look like the descent stage of the Apollo lunar lander that will be capable of landing 7,000 kg payloads on the Moon, and a tanker based on the cargo lander but with oversized propellant tanks.

The tanker will be able to land 7,000 kg of propellant that will be used to refuel the crewed lander, the cargo lander, and still have enough propellant leftover that it will be able to return to the Lunar Orbiting Space Station in low lunar orbit. After returning to the lunar orbiting space station, all three landers will be refueled and prepared for another mission. These landers will use the same storable propellants that were used for the Apollo lunar lander and that are used in the service module of the Orion spacecraft.

A typical landing using the three Return to the Moon lunar landers will start with the landing of the tanker at a landing site near the lunar South Pole. Once the tanker is successfully on the lunar surface, the cargo lander will land nearby. After that, the crewed vehicle will land. It is assumed that the cargo lander will carry a pressurized rover and two small propellant tank trailers for the first landing. The rover will use the trailers to refuel both the cargo lander and the crewed lander for their return trips to low lunar orbit with propellant from the tanker. Once that is done, the crew will use the rover to explore the lunar South Pole area for easily accessible ice deposits that are near an area in permanent sunlight that is large enough for building a lunar base.

For missions requiring only an unmanned rover, the tanker with a partial propellant load can land a 4,700 kg rover on the surface of the Moon and still have enough propellant on board to return to the low lunar orbit space station.

Another way to use this system will be to remove the landing gear from the crewed lander, attach it to the top of the cargo lander, and operate the combination like the original Apollo Lunar Module. Assuming the cargo lander is not damaged when the crewed lander takes off, it can be refueled and sent back to the lunar orbiting space station at a later date.

A second way to use the crewed lander will be as a sub-orbital hopper for sending astronauts to other parts of the Moon on exploration missions from the Moon base. For this type of mission, the lander will use 1/4^th of its propellant to head to a site of interest, 1/4^th to land, and the remaining half to return to the Moon base.

The crewed lander will have a space station departure mass of 4,700 kg and will use 2,300 kg of propellant to land on the Moon. It will require an additional 2,300 kg of propellant from the tanker to return to the low lunar orbit space station. The cargo lander and tanker will both have a space station departure mass of 18,000 kg and will use 8,500 kg of propellant to land on the Moon when fully loaded. They will need 2,300 kg of propellant each for the return to the low lunar orbit space station (no payload). The total amount of propellant required for these three vehicles to land on the Moon and return to the low lunar orbit space station is 26,200 kg. The amount of propellant required for the tanker to land a 4,700 kg unmanned rover on the Moon and return is 10,800 kg.

The advantages of the three Return to the Moon lunar landers are many; the landers are reusable, they build on our experience with the Apollo Lunar Module, they use existing propulsion systems that use storable propellants, they are small enough that they can be sent to the Lunar Orbiting Space Station with existing launch vehicles, and their propellant needs are manageable. Propellant resupply will be discussed in more detail in the article Return to the Moon Space Tug.

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Lunar Surface Exploration

All the articles about the Return to the Moon program show the first mission staying on the lunar surface for 2 weeks. If we are to make effective use of this time on the Moon, the astronauts will need some type of habitat to stay in. Camping out for 2 weeks in a crewed lander that lacks an airlock is not an option. This habitat can be a small inflatable structure, a structure that is designed to fit on top of a cargo lander,

or some kind of pressurized rover that can also be landed by the cargo lander. All of these solutions have been studied many times since the 1960s and the majority of them are within the payload capacity of the proposed cargo lander. One pressurized rover concept that is particularly well suited for this mission is the Space Exploration Vehicle with wheeled chassis. This vehicle is designed to support 2 astronauts for 2 weeks on the lunar surface. Prototypes of this vehicle have already been built and tested on Earth. If the SEV can be ready in time to meet the 2024 deadline, we will not only be returning to the Moon, we will be returning in style. The SEV with chassis and supplies has a mass of approximately 5,000 kg.

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Gateway Station Lunar Lander (L2 Halo orbit)

By comparison, a lunar lander designed to operate from the Gateway Space Station in an L2 Halo orbit is a much larger and more expensive vehicle. Lockheed Martin has proposed a single-stage reusable lander for this that carries a crew of four, a payload of 1,000 kg, has a surface stay time of 2 weeks, and uses a LOX/LH2 propulsion system. According to Lockheed Martin, this lander has a departure mass of 62,000 kg when it leaves the Gateway Space Station, and a dry mass of 22,000 kg when it returns at the end of the mission. The total amount of propellant required for each landing is 39,000 kg.

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Storable versus Cryogenic Propellants

Before the Moon Base is built and cryogenic propellant production using lunar water begins, all the propellants used by the Return to the Moon program will need to be brought up from Earth. The problem with using cryogenic propellants for the initial phases of this program will be the need to develop a cryogenic propellant storage system that can keep the propellants cold and recompress the boil-off gasses. Developing and testing such a system and getting it in place in lunar orbit in time for a 2024 lunar landing adds additional risk to not being able to meet the deadline. If the propellant losses due to boil-off are considered part of the cost of using cryogens then it will be necessary to send enough extra propellant with every shipment to account for this. Unfortunately, if a mission is delayed, the amount of propellant remaining at the lunar space station for the landing could become an issue depending on how long the delay is. Using storable propellants for the first landing, the lunar exploration phase, and the lunar base construction phase of the program eliminates these issues and provides a backup system for when the transition to cryogenic propellants begins in the future.

Ad Astra! (To the Stars)

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Return to the Moon Lunar Station

Return to the Moon Lunar Station

After the launch vehicle and upper stage for the Return to the Moon program are selected, the next step in building an affordable Earth-Moon space transportation system will be to build a Return to the Moon Lunar Station in low lunar orbit. Like the currently planned Gateway Space Station, this Return to the Moon Lunar Station will need the same first two modules, the Power and Propulsion Element (PPE) and the Minimum Habitation Module (MHM). In addition, the Return to the Moon Lunar Station will also need the already planned Gateway Logistics Module. The Gateway Logistics Module is the module that will refuel the lunar landers for going to the Moon and the Orion spacecraft for its return trip to Earth. So other than including the Gateway Logistics Module from the beginning and placing the station in a low lunar orbit, the Return to the Moon Lunar Station will be made from the same components that are already being designed and built for the Gateway Space Station.

The Orbit

As currently planned, the Gateway Space Station is to be placed in a halo orbit around the Earth-Moon L2 Lagrange point. The primary reason for choosing this location is because it takes less velocity change to go from the Lunar Transfer Orbit to the L2 halo orbit than it takes to go to Low Lunar Orbit. The velocity change required to go from Lunar Transfer Orbit to the L2 Halo orbit is 420 m/s. The velocity change required to go from Luna Transfer Orbit to Low Lunar Orbit is 820 m/s. This reduction in velocity makes it possible for the Orion spacecraft to go to the L2 halo orbit and return to the Earth without refueling. The disadvantage to this is that it takes 730 m/s of velocity change to go from the L2 Halo orbit to low lunar orbit. This increase in velocity is added to the lunar lander both when it goes down to the Moon and when it returns to the L2 Halo orbit. The additional propellant required to do this dramatically increases the size, complexity, and cost of the lunar lander. By comparison, lunar landers designed to operate from low lunar orbit are a fraction of the size and cost. These differences will be discussed in more detail in “Return to the Moon Lunar Landers.”

Summary

Selecting the most cost effective orbit for the lunar orbiting space station will be the second most important decision for the Return to the Moon program due to its impact on the size and cost of the lunar lander, the size and cost of the launch vehicle needed to send the lunar lander out to the Moon, and the amount of propellant that will need to be sent to the Moon for its on-going operation. The total difference in cost between the lunar landers designed for these two orbits is huge. The selected space station orbit will also have a significant impact on the cost of lifting lunar water, lunar propellant, lunar oxygen, lunar food, and lunar regolith for shielding, to the station once the lunar base starts to produce these items in quantity. As stated before, designing for low cost is crucial if the Return to the Moon program is to become a Return to Stay program. It will also have a very large impact on the cost of going to Mars once we are ready to do that.

Ad Astra! (To the Stars)

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Return to the Moon Launch Vehicle

Return to the Moon Launch Vehicle

As stated in the previous post, this new series of articles is about how to Return to the Moon by 2024 using existing launch vehicles that are lower in cost than the currently planned Space Launch System.

Of all the flight vehicles that will be required for the Return to the Moon program, the Earth to orbit launch vehicle and the upper stage for accelerating from Low Earth Orbit to Lunar Transfer Orbit, are the largest and most expensive. It is the cost of these two vehicles that will determine the overall cost of the entire program. The reason for this is simple, the apparent velocity required to go from the surface of the Earth to a low Earth parking orbit is 9,000 m/s. The velocity change required for going from the parking orbit to a Lunar Transfer Orbit is 3,200 m/s. The velocity change required to go from the Lunar Transfer Orbit to a Low Lunar Orbit is 820 m/s. Landing on the Moon will require an additional 1,600 m/s to 2,000 m/s depending on how much hover time is required to find a suitable landing spot. So of all the velocity change required for going to the Moon, the launch vehicle and upper stage will supply over 80% of the total. This is why the cost of these two vehicles will determine the overall cost of the program. This is also why making this part of the transportation system affordable is so important if the Return to the Moon program is to be a Return to Stay program.

Falcon Heavy w/ Delta upper stage & Orion spacecraft

The initial Return to the Moon launch vehicle will be the flight-proven Falcon Heavy. When flown as an expendable launch vehicle, the Falcon Heavy can launch 63,800 kg into a due east low Earth orbit. To send a crew to a low lunar orbit space station, the Falcon Heavy will need to launch an Orion spacecraft with a Delta IV Heavy upper stage into Earth orbit. The upper stage of the Delta IV Heavy launch vehicle has a total stage mass of 30,700 kg, a propellant mass of 27,220 kg, and a specific impulse of 462 seconds. The Orion spacecraft with Launch Escape Systems has a launch mass of 33,450 kg. The total of these two items comes out to 64,150 kg. The Launch Escape System on the Orion spacecraft, which has a mass of 7,585 kg, is jettisoned at the same time the core stage of the Falcon Heavy drops away. This reduces the amount of payload going to low Earth orbit to 56,565 kg, well within the maximum payload capacity of the Falcon Heavy. Once the orbiting spacecraft is in the proper position relative to the Moon, the upper stage will then accelerate the Orion spacecraft to Lunar Transfer Orbit velocity and the Orion spacecraft will arrive at the low lunar orbit space station with approximately 300 m/s worth of propellant left in its tanks. As a result, the Orion spacecraft will need to take on approximately 4,500 kg of propellant from the lunar orbiting space station for the return to Earth.

Falcon Heavy w/ Delta upper stage & cargo module

This same launch system is also capable of sending a gross payload of approximately 13,000 kg to the lunar orbiting space station when a payload module is substituted for the Orion crew module. This should be sufficient to deliver the components of the lunar orbiting space station to low lunar orbit as well as the lunar landers.

Falcon Heavy w/ Atlas upper stage & cargo module

Another way to send cargo to the lunar orbiting space station is to launch a 9,000 kg cargo module with an Orion service module on an Atlas V upper stage. The total launch mass for this, including the payload fairing, is approximately 47,400 kg, which is well within the payload capacity of the Falcon Heavy when both side boosters are recovered.

In-Space Refueling

The main issue that some people have with this transportation concept is that the Orion spacecraft does not carry enough propellant for returning to Earth from low lunar orbit without refueling. They consider this to be too risky. Yet one of the main reasons for the Return to the Moon program is to develop a local source of propellant that can be used for crewed expeditions to Mars. This requires in-space refueling. The lunar orbiting space station and lunar landers also require in-space refueling. It is also appropriate to point out that the International Space Station is already being refueled on a regular basis. So why not refuel the Orion spacecraft in lunar orbit?

Summary

The two main advantages of using this system are lower cost and the fact that the Falcon Heavy, Delta IV Heavy upper stage, Atlas V upper stage, and Orion service module, are all existing flight-proven vehicles. Using existing flight-proven vehicles will eliminate any chance of not meeting the 2024 deadline due to development delays.

Ad Astra! (To the Stars)

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Return to the Moon to Stay

Return to the Moon to Stay

It looks like it might finally be happening. It could also be the first step towards humans finally going to Mars, the asteroids, and the moons of Jupiter and Saturn. If all this comes to pass, we will have the privilege of witnessing the start of a new civilization in space, a civilization that will someday grow to span the solar system. If this happens, it will be the greatest civilization that humans have ever built. Five hundred years ago the Great Age of Discovery was getting underway, laying the foundation for the world we live in today. If we are successful with the Return to the Moon program, five hundred years from now the total human population could exceed 100 billion people with 9 out of every 10 of those people living off Earth, on moons, on planets, on asteroids, and space colonies all around the solar system. The lives they lead will be as far beyond us today, as our lives are beyond the people of five hundred years ago.
Is this going to happen? Are we going to do this, or will the Return to the Moon program become another political football that gets zero funding from Congress or is canceled by the next President due to cost? In the short term, the answer to this will depend on who wins the next Presidential election and on the Republicans taking control of the House of Representatives. In the long term, it will depend on how expensive our space transportation system for going to the Moon is. Will this transportation system be so expensive that only a handful of government astronauts get to go, or will it be something that companies and private citizens can eventually afford to use? The answer to that will depend on who wins the battle for control of this program, those who view NASA as a source of never-ending government pork, and those who want to open the high frontier for settlement and development. The only chance the open the high frontier people have to win this argument is to show that an affordable space transportation system can be put together using existing hardware and technology. So far they have not done this.

Can it be done?

Yes, it can. Unfortunately, the answer about how to do this is not simple, it is a multi-step answer that will take time and money to put together.
The first step is building a safe, reliable, and reasonably affordable space transportation system that will get us back to the Moon by 2024. The Space Launch System that is being developed by NASA for this is projected to cost 2 Billion dollars per flight. That is not affordable or sustainable. If the Return to the Moon program is going to open the high frontier for development and settlement it needs a transportation system that costs 1/10th of that. It also needs to be a transportation system that can grow and evolve into something that gets more and more affordable as time progresses.
This is possible. The initial system for doing this will consist of the Orion spacecraft, the Falcon Heavy launch vehicle with a Delta IV Heavy upper stage, a lunar orbiting space station, 3 different kinds of lunar landers all based on the original Apollo Lunar Module, and a small fleet of solar electric powered space tugs for carrying cargo from the International Space Station to the lunar orbiting space station. This article is the first of a series that will describe this system.

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It is time to step into the universe of unlimited possibilities and create the most wondrous future imaginable.

It is time to Open the High Frontier.

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Guiding Vision

All projects have a guiding vision. No project can exist without one. The guiding vision that led to the formation of NASA was created by Wernher Von Braun in the 1950s. It consisted of using large multi-stage rockets for launching satellites, cargo rockets, and manned space shuttles into Earth orbit.

The purpose for this launch system was twofold. It was to allow the United States military to place reconnaissance and communications systems in Earth orbit so as to help prevent a global nuclear war, or allow the United States to dominate such a war should one get started. Its second purpose was to build a space station in Earth orbit that would serve as an assembly site for putting together manned spacecraft that would go to the Moon and Mars.

Space itself was not thought of as a destination in this vision. Space was the high ground for the military, and a place to be crossed in order to go to another planet. Due to the high cost of getting to orbit, space was also not thought of as a place for large scale commercial activities such as orbital industries and asteroid mining. Space was thought of as a place for military and government activities along with a few civilian communications satellites. This is the guiding vision that NASA and the military have been operating on ever since.

There have been other visions.

Over one hundred years ago, Konstantin Tsiolkovsky, the man who worked out the mathematics of rocketry and spaceflight, envisioned space as a new home for mankind. A place where mankind would continue to grow and evolve long after our solar system has died. His vision started with people moving out into the solar system where they would build habitats the size of small moons and who would harvest the asteroids for the raw materials that were needed to live and grow there. Eventually, as our technology improved and as the solar system became more crowded, the more adventurous would eventually take on the challenge of going to other stars, thereby starting a process that would lead to mankind spreading out across the galaxy. It was, and still is, an incredible vision.

In 1976, Gerard O’Neill proposed a similar idea in his book, The High Frontier. This is the book that introduced the world to the idea of Space Colonies, and of space being not just a place to travel through, but as a place to live and build a civilization. The only thing that was missing from this vision was a realistic concept for a launch system that would make spaceflight affordable enough to make this possible.

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Today

From the very beginning, most people who support and follow the space program, do so with the idea that it will eventually lead to the creation of a spacefaring civilization. Yet here we are, 50 years after the first manned Moon landing, and no progress has been made towards opening up the high frontier for development and settlement. Yes, there has been plenty of space science in the form of unmanned spacecraft exploring the solar system, space telescopes for exploring the stars, and space stations for studying the long term effects of zero gravity on humans, but that is it. Where are the orbital factories, orbiting hotels, the manned spacecraft for exploring the solar system, the outposts on the Moon and Mars, the asteroid mining companies, and the large rotating space stations full of people engaged in the development and settlement of space? Where are they? Why don’t they exist? The answer is simple, they don’t exist because NASA is operating on a different guiding vision. If you want to see these things occur then it will be necessary to give NASA a different guiding vision. That guiding vision comes from the President of the United States. The President of the United States gets his input from the American people. So it all comes down to us. What kind of space program do we all want? Do you want one like we have today that does space science and manned spaceflight for only a very few, or do you want one that includes developing the technologies that will make spaceflight affordable to everyone so that all the dreams of space become possible?

Think for a moment, how many of you are truly content with the space program we have today? How many of you are content with NASA’s plans for the next ten years and the rate of progress that is being made on those plans? Do you think those plans will lead to the opening of the high frontier so that anyone who has the dream and desire to go there will be able to go to a spaceport and buy a ticket?

If you are not happy with what is happening, ask yourself what kind of program you would like it to be. Would you choose the space program of today where only a small handful of people get to go to a space station in Earth orbit every year? Would you choose the planned space program of tomorrow, the one that consists of a small, man-tended space station in lunar orbit that will hopefully be the beginning of a return to the Moon in 2028 and maybe a manned mission to Mars 10 or 20 years after that? Or would you rather have a space program that makes spaceflight affordable to everyone so that orbital industries, orbital hotels, commercial asteroid mining operations, commercial ice mines on the Moon, commercial spacecraft for going to the Moon, Mars, and the asteroids, all exist? A program where all of this is done in a fraction of the time and at a fraction of the cost of what NASA currently requires? Which one of these excites you? Which one of these would you like to support and see happen?

The key ingredient that is necessary to make all these commercial activities possible, is making spaceflight affordable to everyone. Currently, it costs $82 Million to send an astronaut to the International Space Station on a Soyuz spacecraft. Obviously, not too many people can afford that. The Dragon 2 spacecraft is supposed to be able to carry a pilot and 6 passengers to the International Space Station for $120 Million. That works out to $20 Million per passenger. While that is a huge improvement over the Soyuz, it is still not a price that many people can afford. In order for commercial manned space activities to start, the cost of getting a person to orbit will need to drop down to the $200,000 dollar range or less. For really large scale space settlement to occur, the price to orbit will need to drop even lower than that. The only known launch concept that can be affordably built with existing technology that has the ability to do this is a Combination Launch System that includes a non-rotating skyhook.

Think about that for a moment. A way to make spaceflight affordable to everyone is truly within our reach. What kind of life would you choose for yourself if you could go to a spaceport and purchase a ticket to orbit and beyond? Would you go to Mars? Would you take a job at a shipyard out near the Moon building spaceships, satellite solar power stations, and Space Colonies? How about signing on as a crew member to a spaceship that is going asteroid mining where you have a good chance of coming home a multi-millionaire? Or would you take any job in space that you could get so that you could build a spacecraft in your spare time and go homestead an asteroid when it was done? In this universe of affordable to everyone spaceflight, if you are college age, you could even apply to go to the United States Space Force Academy to become an officer in the US Space Force. With the skills you will learn there you could get any job in space you want. So what would you choose? Really think about this, we are standing right at the edge of the most amazing future imaginable. All that is needed is to make spaceflight affordable to everyone. This will make possible a future that will make all the possibilities of the past look like nothing in comparison. It is a future without limit. What would you choose for yourself in this future?

If you are happy with the space program of today and its plans for tomorrow then there is nothing for you to do. If you are like me and you want more than that, then it is time to write a letter to the President of the United States and tell him that it is time to enlarge NASA’s mission statement to include the development of affordable to everyone spaceflight. Should you write the President, be sure and send copies of your letter to the Vice President and the head of NASA. You might also want to think about including a copy of this article with your letter. You have nothing to lose by doing this and everything to gain. Let’s make all our dreams of space come true, write the President and tell him about the future you want.

Ad Astra (To the Stars)

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A Vision of the Future

A new video!

This video is about our history of achievements and what that means for our future.

It is also about a vision for making spaceflight affordable to everyone so we can start building a spacefaring civilization.

If this is something that appeals to you, help make it happen by sharing this video with everyone you know.

For more information on this subject read the following articles.

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Opening the High Frontier (the video)

A couple of months ago I started working on a new presentation for the Combination Launch System concept that was to be given at a conference I was thinking of going to. As I worked on it, the presentation kept growing and evolving until I had the idea of making it into a video. As a video it has continued to grow and evolve even more, improving with each change. Even now, after all this time and effort, I am still not 100% sure it is finished, but it feels like the time is right to put it out there in the world and hear what people have to say about it.

I hope you enjoy watching it and I look forward to your comments.

Post Script For all of you who have made comments and suggestions on the video – Thank You. I have done my best to incorporate all of your suggestions into it and the end result is much better.

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Space Exploration and the Future

Affordable transportation systems are what make civilizations possible. It has been that way throughout human history. The same is true of space. Without an affordable way of getting into space, a program of sustained human space exploration that has the potential of growing into a spacefaring civilization will remain an unobtainable dream.

You can see the truth of this in the total number of launches per year. The total number of launches to orbit per year worldwide averages somewhere between 80 and 90. It has been that way for the last 30 years. Based on this, space is not a growth industry. In addition, most of those launches are Earth-orbiting satellites. The total number of manned flights for the same period has averaged about 5 per year and none of those went higher than low Earth orbit.

When you think about those numbers in terms of a sustained program of human space exploration that has the potential of growing into a spacefaring civilization, it becomes clear that we are not even close to getting started. For that to happen, we need to dramatically increase our flight rate.

Equally obvious is the fact that this isn’t going to happen based on NASA’s plans for manned spaceflight over the next decade and beyond.

The reason for this is the high cost of spaceflight.

Now imagine what will be possible once we have affordable to everyone spaceflight.

We can return to the Moon, go asteroid mining, go to Mars, and start building the most incredible civilization the world has ever seen. A civilization that will include planets, moons, asteroids, space-based industries, and space colonies scattered throughout the solar system.

People will be able to buy a ticket to an orbiting hotel for a weekend getaway. People will be able to go to the Moon for their vacation. People will be able to get jobs in space and buy a home on a space station or a space colony. People will be able to build their own spacecraft in their spare time and either go asteroid mining or go homestead an asteroid. It will also be possible to buy a ticket for a trip to Mars or the asteroid belt.

The possibilities are truly unlimited. The only limits will be your imagination, your courage, and how hard you are willing to work to make it happen.

Without affordable to everyone spaceflight, none of this is possible and all we can do is talk about it.

Not too long ago I presented the idea of a combination launch system to a group of space advocates. A combination launch system is a launch system that can be affordably built with existing materials and technology that will make spaceflight affordable to everyone. It works by reducing the amount of apparent velocity the launch vehicle needs to achieve to reach orbit. This allows the launch vehicles to be built 1/10th the size of existing launch vehicles and to be made as single stage vehicles that can make multiple flights per day. It is a system that will open up the high frontier for everyone.

My presentation generated a lot of interest, excitement, and discussion in the group. The next day, in response to that interest, the group leader got up on stage and said, “We are not interested in how we get into space, we are only interested in what comes after!”

I was truly surprised by how much applause he got for that statement. His statement also brought the discussion about the combination launch system to a complete halt.

My question to everyone is simple, “is it really that difficult to understand that affordable to everyone spaceflight is the true foundation that will allow the human race to become a spacefaring people?”

In my experience, it is not possible to build anything without a proper foundation in place, and affordable to everyone spaceflight is the foundation for our becoming a spacefaring people.

Today’s rockets, including the partially reusable ones from SpaceX, will never get the cost of spaceflight down to an amount that will make spaceflight affordable to everyone. They are too big, too expensive, their flight rate is too low, their planned operational life is too short, and their payload fraction is too small. To make spaceflight affordable to everyone it will be necessary to use a different approach. That is what a combination launch system is. It is a different way of getting into space that is based on existing technology that will solve all those problems and make spaceflight affordable to everyone.

If manned space exploration and the building of a spacefaring civilization is something that interests you I hope you will continue reading the articles on this website. Once you are done with that I would like you to consider writing a letter to President Trump or to Vice President Pence about making the building of a combination launch system part of NASA, or the soon to exist Space Force.

It is time for us to do this.

It is time for us to be greater than great.

It is time to make our dreams of the future into reality.

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Building a Spacefaring Civilization

Space, the final frontier.

Today, it is a place of dreams.

Tomorrow, it will be the place of our future.

There have been many visions of our future in space. Visions that include manned spacecraft exploring the solar system,

asteroid mining,

cities on other worlds,

space colonies,

and someday, starships.

In short, space is a place of endless possibilities, endless opportunities, endless wealth, endless dreams, and the place where we will build a spacefaring civilization that will someday spread to the stars.

Some people see our move into space as an option. Others see it as a necessity. Jeff Bezos recently said,

“We must lower the cost of access to space to do these grand things that we’re talking about. This is not something we can choose to do. This is something we must do.”

He is not the first person to say this. The number of people who have made similar statements is too long to list. The collective message is clear. We are in the process of outgrowing our home planet and it is time for us to learn to live and fly in a larger universe if we are to survive.

So why haven’t we done this?

The answer to that is cost.

Today, even with the reusable rockets that are being built by SpaceX and others, the cost of spaceflight is still too high to make building a spacefaring civilization possible. To create that reality we will need to be able to launch thousands of tons and thousands of people into space for a tiny fraction of what we pay today.

That is what this blog is about. How spaceflight can be made affordable to everyone so that we can finally start building that spacefaring civilization.

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The idea of multistage rockets, space travel, and building a spacefaring civilization got its start in the late 1800s when Russian mathematician Konstantin Tsiolkovsky derived the rocket equation. This is the equation that calculates how much propellant a rocket needs to carry to reach a certain speed. This equation is at the heart of everything we do with space travel. It is this equation that explains why spaceflight is so expensive and why we have not been able to start building a spacefaring civilization.

An example of this is the Space Shuttle.

The Space Shuttle had a take-off weight of 5 million pounds. Its maximum payload to low Earth orbit was 50,000 pounds. The reason it had a take-off weight 100 times the size of its payload was the amount of propellant it needed to reach the speed of low Earth orbit.

In order for the Space Shuttle to fly to the International Space Station, it had to go even faster. As a result, it could only carry 25,000 pounds of payload there. This means that for a trip to the International Space Station, the Space Shuttle required a take-off weight that was 200 times the weight of the payload.

Now, let’s take a look at what this high propellant fraction did to the cost.

The total cost to fly the Space Shuttle was $1.5 billion dollars per flight. Breaking that down to dollars per pound of useful payload, the Space Shuttle cost $30,000 dollars per pound to low Earth orbit, and $60,000 per pound when flying to the International Space Station.

Obviously, not very affordable.

There are two reasons for this. First, is the amount of propellant that is required to reach the speed of orbit. Second, is the small amount of useful payload delivered compared to the overall size and cost of the launch vehicle.

This is a problem that exists for all past, and currently existing launch vehicles.

One example of this is the Titan 2 launch vehicle that was used to launch the Gemini spacecraft into low Earth orbit back in the 1960s.

It had a takeoff weight of 331,000 pounds and a gross payload to low Earth orbit of 7,900 pounds. If it had been used as a cargo carrier for hauling freight to a low Earth orbit space station like Skylab, its estimated useful payload capacity would have been in the neighborhood of 2,700 pounds. That is a take-off weight to payload weight ratio of 120:1.

Another example is the Saturn 1B with Apollo spacecraft.

It had a take-off weight of 1.3 million pounds and a gross payload capacity of 44,000 pounds when flying to the Skylab space station. The Apollo spacecraft had a launch weight of 32,000 pounds, which left 12,000 pounds for useful payload. That is a take-off weight to payload weight ratio of 108:1.

A more modern example of this is the Falcon 9 rocket with Dragon spacecraft.

The Falcon 9 with Dragon has a take-off weight of 1.2 million pounds. It can deliver 6,000 pounds of useful payload to the International Space Station. Like the Space Shuttle, it has a take-off weight to payload weight ratio of 200:1 for this mission. Its cost per flight, including the cost of flying the Dragon, is approximately $120 million dollars. That results in a cost of $20,000 dollars per pound delivered to the International Space Station. That is 1/3rd of what the Space Shuttle cost.

The last example is the Falcon Heavy launch vehicle with Dragon spacecraft.

This vehicle has a take-off weight of 3.1 million pounds and should be able to deliver approximately 16,500 pounds of useful payload to the International Space Station when both boosters and the core stage are recovered. That is a take-off weight to payload weight ratio of 188:1. Assuming that the Falcon Heavy with Dragon spacecraft costs $120 million dollars per flight when the boosters and core stage are recovered, the cost per pound to the International Space Station drops to approximately $7,000 dollars per pound. That is approximately 1/8th of what the Space Shuttle cost.

Both the Falcon 9 and the Falcon Heavy reduce the cost of getting to orbit by making as much of the rocket reusable as possible, and by simplifying the design so it is less expensive to build, fly, and maintain. Unfortunately, neither of these launch vehicles has been able to reduce the amount of propellant that is required to reach the speed of orbit. Just like the Space Shuttle, both the Falcon 9 and the Falcon Heavy have a take-off weight to payload weight ratio of approximately 200:1 when flying to the International Space Station. This places a limit on how much cost reduction can be achieved by simplifying the design and making the first stages of the vehicle reusable. So, while both of these vehicles are a wonderful improvement over the Space Shuttle, neither of them is low enough in cost to allow us to start building a spacefaring civilization. For that to happen the cost to orbit will need to drop to a few pennies on the dollar of what the Falcon Heavy costs. That just isn’t going to be possible using launch vehicles that have take-off weight to payload weight ratios this high. In order to get the cost down low enough to build a spacefaring civilization, we need to rethink how we get into space.

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Back in the early-mid 1800s, steamships had a similar problem to today’s launch vehicles. The steam engines of the day burned so much coal that the ships were limited in how far they could travel and still have enough room left over to carry a worthwhile amount of cargo. They solved this problem by breaking up the longer shipping routes into shorter lengths with strategically placed coaling stations. This allowed the early steamships to travel the globe while carrying a lot less coal and a lot more cargo. This significantly reduced the cost of shipping goods and people around the world while allowing the shipping companies to operate at a higher profit margin. It was a win-win solution for everyone.

In the case of Earth to orbit spaceflight, the problem isn’t distance traveled, the problem is the amount of speed the rocket needs to achieve to reach orbit. Since it isn’t possible to place a refueling station halfway up, the only other option is to reduce the amount of speed the launch vehicle needs to achieve to reach orbit. This can be done by adding speed to the launch vehicle at both the beginning and the end of its flight to orbit using externally applied power. This will significantly reduce the amount of propellant the launch vehicle needs to carry, which will allow it to carry more payload.

This is what a Combination Launch System does.

A combination launch system adds velocity to the launch vehicle at the beginning of its flight to orbit using either a catapult,

or by air launching the launch vehicle from high in the atmosphere with a carrier aircraft.

The combination launch system also adds velocity to the launch vehicle at the end of the flight with a non-rotating skyhook.

The end result is that the launch vehicle only needs to carry the propellant for the increase in speed that occurs in the middle part of the flight. The total amount of speed supplied by a mature combination launch system represents up to 1/3 or more of the total speed required for reaching orbit. This reduces the take-off weight to payload weight ratio of the launch vehicle from 200:1 down to 20:1 or less.

This will also allow the launch vehicle to be built as a 100% reusable single-stage vehicle that is much smaller in size than existing launch vehicles.

For example, the Falcon 9, which carries 6,000 pounds of usable payload to the International Space Station, has a take-off weight of 1.2 million pounds. A launch vehicle that is flown as part of a mature combination launch system that has the same payload capacity will have a take-off weight of approximately 120,000 pounds.

An example of what such a vehicle might look like is the X-24C that was designed by Lockheed back in the 1970s.

(photo from fantastic-plastic.com)

In addition, due to its smaller size, lack of drop off components, and complete reusability, this launch vehicle will also be able to make up to 6 flights per day to the skyhook when the skyhook is in an equatorial orbit.

It is the total of these changes that will reduce the cost of getting to orbit down to an amount that anyone can afford. It is the total of these changes that will also allow us to finally start building orbiting hotels and orbital industries on a commercial basis.

But this is not all.

It takes more than affordable Earth to orbit transportation to build a spacefaring civilization. Many of the astronauts have described low Earth orbit as barely skimming the cloud tops. Others have described it as Earth’s doorstep.

To truly step out into the solar system and build a real spacefaring civilization, it will also be necessary to make Earth orbit to escape velocity spaceflight affordable to everyone. Fortunately, the upper end of the non-rotating skyhook makes this possible. Just like the lower end of the skyhook that moves at less than orbital velocity for its altitude, the upper end of the skyhook is moving faster than orbital velocity for its altitude. This allows a spacecraft that releases from the upper end of a suitably long skyhook to be given a boost to escape velocity without using any of its onboard propellant. This reduction in propellant will reduce the size and cost of a spaceship for traveling to the Moon, Mars, and the asteroids to an amount that just about anyone can afford to use. This is what will make Moon bases and cities on Mars both affordable and possible. This will also make asteroid mining possible. Once we have affordable access to lunar materials and the asteroids, building space colonies will also become possible.

In short, a combination launch system is like the transcontinental railroad that opened up the American West. Once it is built, it will open up the solar system for settlement and development and allow us to finally start building a real spacefaring civilization.

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