Orbital airship
Encyclopedia
The orbital airship, also called the space blimp, is a proposed space transportation
system that carries payloads to and from low Earth orbit
. It is intended to achieve orbital altitude and orbital velocity
using low thrust rocket propulsion
by flying in the manner of an airship
rather than a rocket
, employing buoyancy
and aerodynamic lift rather than vertical thrust to sustain flight
during its ascent.
, there are three components. A conventional airship (“Ascender”) lifts payloads up to 30 to 43 kilometers above the ground – roughly the maximum altitude a conventional airship can achieve. At this altitude the second component, a docking station (“Dark Sky Station”), acts as a resupply station for the third stage. The third stage is an orbital airship (“Orbital Ascender”), which takes payloads to low earth orbit (i.e., it accelerates itself horizontally to orbital velocity and gains an altitude
in excess of 100 km) over several days.
Their program sponsors and business revenues have continued to provide their development costs thus far. They funded part of their operation until 2005 with a contract for development of military communication and surveillance airships designed to hover over battlefields at altitudes too high for conventional anti-aircraft systems. They had hoped to fly a prototype in 2005, but the vehicle was damaged during testing and the contract was discontinued. Other vehicles are still under development, and JP aerospace has subsequently flown several aerostats as testbeds for ATO hardware and techniques.
Multiple vehicles are needed because any airship made strong enough to survive the relatively turbulent lower atmosphere would be too heavy to lift payloads to space. An orbital airship would need to be built larger to improve its buoyancy
-to-weight
ratio, with thinner walls, and designed to operate at notably lower pressure. Even in the outer fringes of the atmosphere, helium
is still lighter than air
.
Both the conventional and orbital airships will be V-shaped for aerodynamics. The orbital airship wings will be shaped to function as hypersonic
airfoil
s and can be angled upwards to help generate lift
. As the airship gains altitude, drag
will reduce, allowing the vehicle to accelerate with increasing altitude. According to JP Aerospace, there is a wide margin of drag-to-power
ratios within which an orbital airship can attain orbit.
Early development stages of the station and the airships will be powered by fuel cell
s. In the long term, the surface of these objects can be sprayed with a thin-film solar cell
, which, while inefficient in energy conversion, would benefit from light weight, simplicity, and the large surface area. The final version of the orbital ascender can also employ refractory
materials on the wing leading edge to reduce thermal wear. JP Aerospace’s US patent
#7614586 identifies the orbital ascender’s propulsion system
as chemical and/or electric rockets. John Powell’s Floating to Space cites several candidate propulsion systems. JP Aerospace is currently developing a hybrid chemical/electric rocket engine.
Their estimated marginal costs for cargo are one dollar per ton per mile of altitude, as quoted to Dr. Jerry Pournelle
at the 2004 Space Access Conference
has been previously proposed by aerospace researchers or featured in works of science fiction.
Other groups in addition to JP Aerospace have recently claimed to be researching or actively developing alternative orbital airship designs.
JP Aerospace has also acknowledged competition from other organizations in its suborbital applications.
is estimated at 0.00086 kg per cubic meter according to the International Standard Atmosphere
model. To be lighter than air at this altitude, the airship's total density – the weight of its gas plus its cargo and structure divided by its total volume – must be less than 0.00086 kg per cubic meter. This should be achievable with hydrogen
, helium, and/or with heated gas inside the balloon, and/or with partially rigid supports. For comparison, the ISAS BU60-1
scientific balloon, holder of the world altitude record for an unmanned balloon as of 2009, flew to 53.0 km. With an inflated mass of 39.77 kg and a maximum volume of 60000 cubic meters, the total density of BU60-1 was 0.00066 kg per cubic meter.
It will be necessary for all ATO system components to achieve comparably low total density while still transferring sufficient propellant
and payload for the orbital ascender to ultimately achieve orbit, or the system components will not have the necessary buoyancy to attain the altitudes stated by JP Aerospace. Additionally, the system components are claimed to be suitable for repeated use.
The square-cube law
– common in many engineering calculations – is expected to be critical to the orbital airship design. The material needed to contain a given space increases as the square of its dimensions, while the volume of the space increases as per the cube of its dimensions. In theory one can create a lead balloon, or a concrete canoe
, or an ironclad ship and have it float if it is of sufficient size, although this may not always be practical.
To achieve significantly higher altitudes, one needs very large volumes and/or very strong materials with low density that are affordable in bulk. Nevertheless, a mesosphere
based high altitude platform could offer many potential advantages. One could harvest oxygen and store it for further stages – which might resemble a more conventional launch vehicle. Conditions in the mesosphere are very different than those
at lower altitudes in the stratosphere
or higher in the thermosphere
. Such a platform might also serve as a radio repeater
or a relay point while receiving maser
or laser
energy from the ground.
A mesosphere-based high-altitude platforms could also increase its altitude temporarily—in a non-lighter-than-air manner—using energy from ground based or solar sources.
. The size of this vehicle will pose unique problems for design, construction, maintenance, deployment and storage.
The other vehicles in JP Aerospace’s proposed architecture are significantly larger, with expected volumes among the largest inflatable structures of any type ever constructed. These vehicles are intended to remain in operation indefinitely (alleviating requirements for deployment and storage), and their operating environments are not predicted to be as structurally demanding as those of the first stage Ascender airship. However, size related problems of design, construction and maintenance will remain.
Additional helium will need to be added to the station and airship to help keep it buoyant. Refueling and resupply of other materials may also be required.
Hypersonic gas dynamics will create high temperature flow across the wings of the orbital ascender, and heat transfer
along the wings must be kept low enough to avoid damage.
Regulatory hurdles are expected, beginning during the development phase. The vehicles will potentially traverse the airspace
of several nations, and will need to meet legal regulations for flight in every country that they traverse the internationally recognized airspace of.
The orbital ascender faces some of the same harsh environmental conditions as a space elevator
, such as elemental oxygen
, radiation
and space debris
.
JP Aerospace believes the problems can be solved, and has already begun tests of the Ascender. They also point out that, if something goes wrong on an airship, there is more time to correct problems than on a rocket
.
. Thus it would have potential applications beyond those of a direct launch rocket.
The vehicles could support extended research and exploration in the mesosphere and/or thermosphere, which are largely unexplored regions of the atmosphere.
The Dark Sky Station could provide a permanent station for both equipment and personnel. It could function as an outpost
or port
for space exploration in some of the same ways proposed for space station
s – including outposts on other planets with atmospheres – and serve some of the roles filled by orbital satellite
s today. Possibilities for space tourism
and space manufacturing
are greatly expanded by the presence of a permanent station. Multiple dark sky stations could support enough living quarters to make residency a viable option.
The orbital airship might provide relatively low cost shipping
and transportation, both suborbital and earth-to-orbit. The orbital airship would also be capable of providing orbit-to-earth shipping with equal or greater cargo capacity.
An orbit
al, thermosphere, or even mesosphere airship would face many practical and theoretical challenges and would represent a remarkable technical achievement.
Spacecraft propulsion
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
system that carries payloads to and from low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
. It is intended to achieve orbital altitude and orbital velocity
Orbital velocity
Orbital velocity can refer to the following:* The orbital speed of a body in a gravitational field.* The velocity of particles due to wave motion, in particular in wind waves....
using low thrust rocket propulsion
Spacecraft propulsion
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
by flying in the manner of an airship
Airship
An airship or dirigible is a type of aerostat or "lighter-than-air aircraft" that can be steered and propelled through the air using rudders and propellers or other thrust mechanisms...
rather than a rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...
, employing buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...
and aerodynamic lift rather than vertical thrust to sustain flight
Flight
Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....
during its ascent.
JP Aerospace’s Airship To Orbit
In the Airship To Orbit (ATO) design envisioned by JP AerospaceJP Aerospace
JP Aerospace is a volunteer-based organization dedicated to achieving affordable access to space. They have been hired by the U.S. Air Force to provide concepts to allow rapid launch of battlefield communication and monitoring systems....
, there are three components. A conventional airship (“Ascender”) lifts payloads up to 30 to 43 kilometers above the ground – roughly the maximum altitude a conventional airship can achieve. At this altitude the second component, a docking station (“Dark Sky Station”), acts as a resupply station for the third stage. The third stage is an orbital airship (“Orbital Ascender”), which takes payloads to low earth orbit (i.e., it accelerates itself horizontally to orbital velocity and gains an altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
in excess of 100 km) over several days.
Their program sponsors and business revenues have continued to provide their development costs thus far. They funded part of their operation until 2005 with a contract for development of military communication and surveillance airships designed to hover over battlefields at altitudes too high for conventional anti-aircraft systems. They had hoped to fly a prototype in 2005, but the vehicle was damaged during testing and the contract was discontinued. Other vehicles are still under development, and JP aerospace has subsequently flown several aerostats as testbeds for ATO hardware and techniques.
Multiple vehicles are needed because any airship made strong enough to survive the relatively turbulent lower atmosphere would be too heavy to lift payloads to space. An orbital airship would need to be built larger to improve its buoyancy
Buoyancy
In physics, buoyancy is a force exerted by a fluid that opposes an object's weight. In a column of fluid, pressure increases with depth as a result of the weight of the overlying fluid. Thus a column of fluid, or an object submerged in the fluid, experiences greater pressure at the bottom of the...
-to-weight
Weight
In science and engineering, the weight of an object is the force on the object due to gravity. Its magnitude , often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus:...
ratio, with thinner walls, and designed to operate at notably lower pressure. Even in the outer fringes of the atmosphere, helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
is still lighter than air
Lighter than air
Lighter than air refers to gases that are buoyant in air because they have densities lower than that of air .Some of these gases are used as lifting gases in lighter-than-air aircraft, which include free balloons, moored balloons, and airships, to make the whole craft, on average, lighter than air...
.
Both the conventional and orbital airships will be V-shaped for aerodynamics. The orbital airship wings will be shaped to function as hypersonic
Hypersonic
In aerodynamics, a hypersonic speed is one that is highly supersonic. Since the 1970s, the term has generally been assumed to refer to speeds of Mach 5 and above...
airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
s and can be angled upwards to help generate lift
Lift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
. As the airship gains altitude, drag
Drag equation
In fluid dynamics, the drag equation is a practical formula used to calculate the force of drag experienced by an object due to movement through a fully enclosing fluid....
will reduce, allowing the vehicle to accelerate with increasing altitude. According to JP Aerospace, there is a wide margin of drag-to-power
Power (physics)
In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...
ratios within which an orbital airship can attain orbit.
Early development stages of the station and the airships will be powered by fuel cell
Fuel cell
A fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. Hydrogen is the most common fuel, but hydrocarbons such as natural gas and alcohols like methanol are sometimes used...
s. In the long term, the surface of these objects can be sprayed with a thin-film solar cell
Solar cell
A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....
, which, while inefficient in energy conversion, would benefit from light weight, simplicity, and the large surface area. The final version of the orbital ascender can also employ refractory
Refractory
A refractory material is one that retains its strength at high temperatures. ASTM C71 defines refractories as "non-metallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above...
materials on the wing leading edge to reduce thermal wear. JP Aerospace’s US patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
#7614586 identifies the orbital ascender’s propulsion system
Spacecraft propulsion
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
as chemical and/or electric rockets. John Powell’s Floating to Space cites several candidate propulsion systems. JP Aerospace is currently developing a hybrid chemical/electric rocket engine.
Their estimated marginal costs for cargo are one dollar per ton per mile of altitude, as quoted to Dr. Jerry Pournelle
Jerry Pournelle
Jerry Eugene Pournelle is an American science fiction writer, essayist and journalist who contributed for many years to the computer magazine Byte and has since 1998 been maintaining his own website/blog....
at the 2004 Space Access Conference
Similar proposals
Use of large balloons for aerobrakingAerobraking
Aerobraking is a spaceflight maneuver that reduces the high point of an elliptical orbit by flying the vehicle through the atmosphere at the low point of the orbit . The resulting drag slows the spacecraft...
has been previously proposed by aerospace researchers or featured in works of science fiction.
Other groups in addition to JP Aerospace have recently claimed to be researching or actively developing alternative orbital airship designs.
JP Aerospace has also acknowledged competition from other organizations in its suborbital applications.
Potential problems
A practical orbital airship design must deal with multiple engineering challenges of both high altitude balloons and spacecraft.Buoyancy
One potential limitation is the weight of the material used to contain the airship's gas. For example, air density at 51 km in the mesosphereMesosphere
The mesosphere is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere. In the mesosphere temperature decreases with increasing height. The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally occurring...
is estimated at 0.00086 kg per cubic meter according to the International Standard Atmosphere
International Standard Atmosphere
The International Standard Atmosphere is an atmospheric model of how the pressure, temperature, density, and viscosity of the Earth's atmosphere change over a wide range of altitudes. It has been established to provide a common reference for temperature and pressure and consists of tables of...
model. To be lighter than air at this altitude, the airship's total density – the weight of its gas plus its cargo and structure divided by its total volume – must be less than 0.00086 kg per cubic meter. This should be achievable with hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, helium, and/or with heated gas inside the balloon, and/or with partially rigid supports. For comparison, the ISAS BU60-1
Flight altitude record
These are the records set for going the highest in the atmosphere from the age of ballooning onward. Some records are certified by Fédération Aéronautique Internationale.-Fixed-wing aircraft:-Piston-driven propeller aeroplane:...
scientific balloon, holder of the world altitude record for an unmanned balloon as of 2009, flew to 53.0 km. With an inflated mass of 39.77 kg and a maximum volume of 60000 cubic meters, the total density of BU60-1 was 0.00066 kg per cubic meter.
It will be necessary for all ATO system components to achieve comparably low total density while still transferring sufficient propellant
Propellant
A propellant is a material that produces pressurized gas that:* can be directed through a nozzle, thereby producing thrust ;...
and payload for the orbital ascender to ultimately achieve orbit, or the system components will not have the necessary buoyancy to attain the altitudes stated by JP Aerospace. Additionally, the system components are claimed to be suitable for repeated use.
The square-cube law
Square-cube law
The square-cube law is a principle, drawn from the mathematics of proportion, that is applied in engineering and biomechanics. It was first demonstrated in 1638 in Galileo's Two New Sciences...
– common in many engineering calculations – is expected to be critical to the orbital airship design. The material needed to contain a given space increases as the square of its dimensions, while the volume of the space increases as per the cube of its dimensions. In theory one can create a lead balloon, or a concrete canoe
Concrete canoe
A concrete canoe is a canoe made of concrete, typically created for an engineering competition.In spirit, the event is similar to that of a cardboard boat race—make the seemingly unfloatable float...
, or an ironclad ship and have it float if it is of sufficient size, although this may not always be practical.
To achieve significantly higher altitudes, one needs very large volumes and/or very strong materials with low density that are affordable in bulk. Nevertheless, a mesosphere
Mesosphere
The mesosphere is the layer of the Earth's atmosphere that is directly above the stratosphere and directly below the thermosphere. In the mesosphere temperature decreases with increasing height. The upper boundary of the mesosphere is the mesopause, which can be the coldest naturally occurring...
based high altitude platform could offer many potential advantages. One could harvest oxygen and store it for further stages – which might resemble a more conventional launch vehicle. Conditions in the mesosphere are very different than those
at lower altitudes in the stratosphere
Stratosphere
The stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. It is stratified in temperature, with warmer layers higher up and cooler layers farther down. This is in contrast to the troposphere near the Earth's surface, which is cooler...
or higher in the thermosphere
Thermosphere
The thermosphere is the biggest of all the layers of the Earth's atmosphere directly above the mesosphere and directly below the exosphere. Within this layer, ultraviolet radiation causes ionization. The International Space Station has a stable orbit within the middle of the thermosphere, between...
. Such a platform might also serve as a radio repeater
Repeater
A repeater is an electronic device that receives asignal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.-Description:...
or a relay point while receiving maser
Maser
A maser is a device that produces coherent electromagnetic waves through amplification by stimulated emission. Historically, “maser” derives from the original, upper-case acronym MASER, which stands for "Microwave Amplification by Stimulated Emission of Radiation"...
or laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
energy from the ground.
A mesosphere-based high-altitude platforms could also increase its altitude temporarily—in a non-lighter-than-air manner—using energy from ground based or solar sources.
Size
The final version of JP Aerospace’s first-stage Ascender airship will be among the largest airships ever constructed, with an expected volume (57 million cubic feet) greater than seven times that of the HindenburgLZ 129 Hindenburg
LZ 129 Hindenburg was a large German commercial passenger-carrying rigid airship, the lead ship of the Hindenburg class, the longest class of flying machine and the largest airship by envelope volume...
. The size of this vehicle will pose unique problems for design, construction, maintenance, deployment and storage.
The other vehicles in JP Aerospace’s proposed architecture are significantly larger, with expected volumes among the largest inflatable structures of any type ever constructed. These vehicles are intended to remain in operation indefinitely (alleviating requirements for deployment and storage), and their operating environments are not predicted to be as structurally demanding as those of the first stage Ascender airship. However, size related problems of design, construction and maintenance will remain.
Other potential problems
The final design must address several other potential problems.Additional helium will need to be added to the station and airship to help keep it buoyant. Refueling and resupply of other materials may also be required.
Hypersonic gas dynamics will create high temperature flow across the wings of the orbital ascender, and heat transfer
Heat transfer
Heat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
along the wings must be kept low enough to avoid damage.
Regulatory hurdles are expected, beginning during the development phase. The vehicles will potentially traverse the airspace
Airspace
Airspace means the portion of the atmosphere controlled by a country above its territory, including its territorial waters or, more generally, any specific three-dimensional portion of the atmosphere....
of several nations, and will need to meet legal regulations for flight in every country that they traverse the internationally recognized airspace of.
The orbital ascender faces some of the same harsh environmental conditions as a space elevator
Space elevator
A space elevator, also known as a geostationary orbital tether or a beanstalk, is a proposed non-rocket spacelaunch structure...
, such as elemental oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
and space debris
Space debris
Space debris, also known as orbital debris, space junk, and space waste, is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. These objects consist of everything from spent rocket stages and defunct satellites to erosion, explosion...
.
JP Aerospace believes the problems can be solved, and has already begun tests of the Ascender. They also point out that, if something goes wrong on an airship, there is more time to correct problems than on a rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...
.
Potential applications
JP Aerospace’s Airship to Orbit architecture is three distinct vehicles plus ground controlMission Control Center
A mission control center is an entity that manages aerospace vehicle flights, usually from the point of lift-off until the landing or the end of the mission. A staff of flight controllers and other support personnel monitor all aspects of the mission using telemetry, and send commands to the...
. Thus it would have potential applications beyond those of a direct launch rocket.
The vehicles could support extended research and exploration in the mesosphere and/or thermosphere, which are largely unexplored regions of the atmosphere.
The Dark Sky Station could provide a permanent station for both equipment and personnel. It could function as an outpost
Human outpost
Human outposts are artificially-created, controlled human habitats located in environments inhospitable for humans, such as on the ocean floor, in space or on another planet....
or port
Port
A port is a location on a coast or shore containing one or more harbors where ships can dock and transfer people or cargo to or from land....
for space exploration in some of the same ways proposed for space station
Space station
A space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...
s – including outposts on other planets with atmospheres – and serve some of the roles filled by orbital satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s today. Possibilities for space tourism
Space tourism
Space Tourism is space travel for recreational, leisure or business purposes. A number of startup companies have sprung up in recent years, hoping to create a space tourism industry...
and space manufacturing
Space manufacturing
Space manufacturing is the production of manufactured goods in an environment outside a planetary atmosphere. Typically this includes conditions of microgravity and hard vacuum.Manufacturing in space has several potential advantages over Earth-based industry....
are greatly expanded by the presence of a permanent station. Multiple dark sky stations could support enough living quarters to make residency a viable option.
The orbital airship might provide relatively low cost shipping
Shipping
Shipping has multiple meanings. It can be a physical process of transporting commodities and merchandise goods and cargo, by land, air, and sea. It also can describe the movement of objects by ship.Land or "ground" shipping can be by train or by truck...
and transportation, both suborbital and earth-to-orbit. The orbital airship would also be capable of providing orbit-to-earth shipping with equal or greater cargo capacity.
Skepticism
Nobody outside JP Aerospace seems to know how the problems of high drag and low lift/drag ratios that are very typically found at hypersonic speeds might be overcome in such a vehicle, and a large degree of skepticism exists.An orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
al, thermosphere, or even mesosphere airship would face many practical and theoretical challenges and would represent a remarkable technical achievement.