V-Infinity

A book about moving into space

by Jerome L Wright

Available 2017 Q3.


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V-Infinity shows that all aspects of space development can be done in a minimum cost manner, which means that everyday people can participate. Space development can begin when costs come down.

The book is written in four parts. An excerpt:

Part One. Escape Velocity

Launch Vehicles

The primary objective for a space launch vehicle intended to carry people and cargo into Earth orbit is minimum cost with safety. Minimum cost means simplicity in design and operations, and simplicity means reliability and safety.

We want more than just transportation, though. We want to build permanent facilities in Earth orbit where people can live and work - with their families. This adds more design requirements to the launch vehicle. Fortunately, this can be done without giving up the objective of minimum cost. We actually want a minimum cost launch vehicle that carries people, payload, and habitat elements.

The vehicle should be able to carry at least 30 to 40 tons of payload into orbit to be really useful. The permanent facility should be in an orbit with a minimum amount of aerodynamic drag while also low enough to avoid serious radiation levels. An orbit of 600 kilometers is selected to meet these requirements, which is significantly farther out than the International Space Station at 410 kilometers. Orbits of around 500-700 kilometers might also be acceptable.

Launching from the equator into an equatorial orbit allows a launch vehicle to deliver its maximum payload. This is important for the large spacecraft that go on to geosynchronous orbit as well as for the orbital habitat. Europe, Russia, and Brazil can launch into near-equatorial orbits. The US government does not currently allow US-built launch vehicles to operate from land sites outside the US. Ocean launches might be allowable.

Costs of launch and space vehicles can be controlled through a process called minimum-cost design (MCD). All aspects of a vehicle are reviewed to find design approaches that meet the requirements, but cost the least among the available options. This definitely does not mean using the cheapest parts or inferior parts. The success of this approach takes advantage of the fact that letting size increase means adding some more structure and propellant, both of which are relatively inexpensive. It is a well known fact in the industry that minimizing mass leads to cost increases. MCD takes things in the opposite direction.

The Aurex Launch Vehicle

Aurex is a large, simple launch vehicle designed to carry people, cargo, and habitat elements into orbit. There is both general and technical information describing the vehicle. The book shows how a habitat can be constructed by using Aurex. The expandable habitat provides Martian-level artificial gravity and could be home to a few thousand people. Aurex will be capable of carrying 30 to 50 people along with some cargo, or 40 to 50 tons of just cargo.

Aurex is a proposed launch vehicle with a diameter of 10 meters, with a minimum-cost design (MCD) architecture. It has the same diameter as the Saturn V. It is roughly similar to Robert Truax's Sea Dragon in that it is a large two-stage pressure-fed design, but substantially smaller in size.

The Aurex project is defined by:

Objectives

  • Establish orbital infrastructure
  • Establish a commercial high-capacity, low-cost transportation system
  • Open space for access by large numbers of people
  • Create transportation, housing, and jobs for large numbers of people.

Mission

  1. Assemble low-cost orbital habitats and other structures
  2. Deliver large payloads at minimal cost
  3. Carry large numbers of people into space at minimal cost
  4. Support Mars settlements and Lunar operations.

The design is driven in large part by the objective of getting as much habitable volume into orbit as practical while under the constraint of achieving minimal cost.

The core vehicle consists of two-stages. The 2nd is the orbital stage, which has two roles:

  • Transportation as the orbital stage
  • Infrastructure as a construction module.

It is made of maraging steel (200-250 grade), a tough, malleable steel with corrosion resistance because of its nickel content. It is easy to work with and does not require heat treatment for use as a habitat structure, although heat treatment is employed for launch loads.

Liquid oxygen is the choice for oxidizer because of its performance. Liquified natural gas (LNG), which is mostly methane, is selected as fuel because of its better performance than kerosene and easier handling than liquid hydrogen. It is inexpensive and readily available. However, LNG's advantage over kerosene is modest, so kerosene remains a viable option.

The 1st stage is made of the same steel and uses the same propellants. This stage is initially expendable, but it may later be recovered from a soft water impact for refurbishment and reuse.

The optimal diameter for the vehicle is 10 to 11 meters for its role in supporting permanent infrastructure in orbit. Ten meters is selected as a working value here.

Configuration

Both stages have a single engine, pressure fed, with fixed or gimbaled mounting; the baseline is fixed mounting for both stages.

Each stage uses movable steering engines that burn the same propellants, tapping off of the main tanks.

Space Town

The Space Town concept is a permanent habitat in close Earth orbit that rotates to provide artificial gravity. It is designed to support a substantial population of long-term or permanent inhabitants. The process of creating Space Town would be to start small and simple, then progress to a larger habitat, always keeping in mind that the budget is limited.

The Space Town concept is a minimum cost design that can get people living in space on perhaps the smallest practical budget. Minimum-cost design methodology is essential for success.

The primary structure can be delivered in seven launches to near Earth orbit.

The Orbit

Radiation in space is a serious issue. Permanent residents could spend decades, even their entire lives, in orbital habitats, so their protection is a critical factor. Fortunately, there is a location that satisfies radiation and other adverse factors. In orbits inside of 400 km, aerodynamic drag and the presence of orbital debris are problems. Beyond 1000 km, radiation in the Van Allen Belts is prohibitive. Also, the greater the size of the orbit, the greater is the loss of payload coming out from Earth.

The South Atlantic Anomaly over the southern Atlantic Ocean and South America is a place where charged particles from the Van Allen Belts reach to the upper atmosphere. That is a region to be avoided for people who would spend long periods of time in orbit. This means the orbit should have an inclination no greater than about 5 degrees, but not over 3 degrees is a better choice.

The orbits dictated by these considerations are equatorial, or at most not over 3 degrees inclination. The best altitude ranges from about 500 to 800 km. An equatorial orbit of 600 km is taken here as the best choice. With this orbit, or one very close to it, drag makeup maneuvers are needed only once every few years. Additionally, radiation shielding is not needed beyond that provided by the pressure hull and micrometeoroid shielding. (Orbital Space Settlement Radiation Shielding by Al Globus and Joe Strout)

In summary, the suitable region is an equatorial ring about 300 km high-from 500 km to 800 km-and about 700 km thick-less than 3 degrees from the equator.

A consequence of this is that launch vehicles must depart from a site at the equator or close to it.

Overall Configuration

The initial configuration consists of a spindle and six habitation modules that are aligned radially from the spindle. The habitation modules and part of the spindle rotate as a unit to provide artificial gravity up to 0.4 g (Martian gravity). The configuration is selected to provide a simple, conventional method of assembly, which optionally could be done with automated docking before people come aboard.