The SpaceLiner is a very long-term project, and does not currently have funding lined up to initiate system development
as of 2017. Projections in 2015 were that if adequate funding was
eventually secured, the SpaceLiner concept might become an operational spaceplane in the 2040s.
Concept
The SpaceLiner concept consists of a two-stage, vertical takeoff, horizontal landing
configuration with a large uncrewed booster and a crewed stage designed
for 50 passengers and 2 crew members. The fully reusable system is
accelerated by a total of eleven liquid rocket engines (9 for the
booster stage, 2 for the passenger stage), which are to be operated
using cryogenic liquid oxygen (LOX) and hydrogen (LH2).
After engine cut-off, the passenger stage will enter a high-speed
gliding flight phase and shall be capable of travelling long
intercontinental distances within a very short time. Altitudes of 80
kilometers and speed beyond Mach
20 are projected, depending on the mission and the associated
trajectory flown. SpaceLiner flight times from Australia to Europe, the
chosen reference mission, should take 90 minutes. Shorter distances,
such as Europe to California for example, would then be achievable in no
more than 60 minutes.
Acceleration loads for the passengers, and only during the propelled
section of the flight, are designed to remain below 2.5 g, and well
below those experienced by the Space Shuttle astronauts.
The concept design also foresees the passenger cabin to function
as an autonomous rescue capsule which can be separated from the vehicle
in case of an emergency, thus allowing the passengers to return safely
to Earth.
A key aspect of the SpaceLiner concept is its full reusability
and vehicle mass-production, which would closely resemble production
rates of the aviation industry. Serial production is expected to deliver
a significant increase in cost effectiveness compared to conventional
space transportation systems of the early 2000s.
A major challenge lies in improving the safety standards and especially
the robustness and reliability of space components such as rocket
engines, so that they will become suitable for the daily operation of a
passenger transporter like the SpaceLiner, while also meeting the
required reusability criteria.
As of 2013, the concept study was funded by DLR's internal resources, as well as in the context of EU-FP7
funded projects such as FAST20XX and CHATT. In addition to DLR, various
partners from the European aerospace sector are involved.
History of SpaceLiner development up to version 7
Concept development
At
the end of 2012 investigations and ongoing studies conducted within
context of the FAST20XX framework led to the refinement and definition
of the SpaceLiner 7 version.
Based on the results of previous studies, development has been
progressing continuously with increasingly detailed and in-depth
considerations, modelling and simulations of the various subsystems, and
their design and integration being performed. Selected variants to the
baseline configuration given different requirements and specifications
were studied with associated results influencing and redirecting the
entire configuration process.
SpaceLiner 1 was the first version, conceived in 2005.
SpaceLiner 2 refers to the first version, which featured the integration of an innovative active cooling system
for the areas of particularly high thermal stresses during atmospheric,
re-entry, being the nose and wing leading edge sections.
The SpaceLiner 4 concept is a 2015 evolution of version 2
with improved aerodynamic and flight dynamic characteristics. Based on
this configuration, various technologies necessary for the SpaceLiner
were experimentally and numerically examined, research that was funded
by the EU research project FAST20XX.
As of 2015, the latest configuration under study at the DLR is the SpaceLiner 7.
Based on results obtained from application of numerical optimisation
methods which achieved an improvement of the aerodynamic, thermal and
structural-mechanical properties in hypersonic flight, the initial
double delta wing
of previous versions has been modified and replaced by a single delta
wing. Presently, subsystems such as the passenger cabin, the cryogenic
tanks, the propellant feed system and the vehicle thermal protection have been preliminarily defined and integrated.
Studies have also been carried out on the economic and logistical
aspects of the concept, with preliminary calculations of expected
program development and production costs given necessary assumptions.
Classification of possible routes for the SpaceLiner
Possible routes, which have then formed the basis of trajectory
analyses for SpaceLiner, have been identified. These are classified and
grouped in terms of their distances, with Class 1 representing the
longest route, and Class 3 describing the shortest yet still
economically interesting and relevant distance. In line with this, a
modified version of the SpaceLiner 7 capable of flying medium long-haul
distances while carrying 100 passengers has been examined. Given the
name SL7-100, this concept variant is suitable for Class 2 and Class 3
distance flights.
To accommodate for the different SpaceLiner configurations, a long and
short version of the booster stage have therefore been considered to
accordingly fulfill the mission requirements depending on the required
range, either in combination with the 50 or 100-passenger stage version.
In addition, research into possible spaceport variants has been
performed, determining mainland, offshore platform and artificial island
possibilities, as well as the required infrastructure for a potential
SpaceLiner spaceport.
Technical data
SpaceLiner7 drawings
The specifications of the SpaceLiner 7 passenger version are:
The SpaceLiner concept intends to use a single type of reusable liquid rocket engine, which operates in the full-flow staged combustion
cycle mode. Having a common engine design for both SpaceLiner stages is
in line with system commonality and is projected to support cost
optimisation in both the development and production phases. The nozzle
expansion ratio is adapted to the different missions of the booster and
passenger stages. Furthermore, liquid hydrogen and liquid oxygen will be used as the propellants, a combination which is both very powerful while still remaining eco-friendly.
According to the AIAA Space Logistics Technical Committee, space logistics is
... the theory and practice of driving space system design for
operability, and of managing the flow of material, services, and
information needed throughout a space system lifecycle.
However, this definition in its larger sense includes terrestrial
logistics in support of space travel, including any additional "design
and development, acquisition, storage, movement, distribution,
maintenance, evacuation, and disposition of space materiel", movement of
people in space (both routine and for medical and other emergencies),
and contracting and supplying any required support services for
maintaining space travel.
History
Wernher von Braun spoke of the necessity (and the underdevelopment) of space logistics as early as 1960:
"We have a logistics problem coming up in space ... that will
challenge the thinking of the most visionary logistics engineers. As you
know, we are currently investigating three regions of space:
near-Earth, the lunar region, and the planets. While it is safe to say
that all of us have undoubtedly been aware of many or most of the
logistics requirements and problems in the discussion, at least in a
general way, I think it is also safe to state that many of us have not
realized the enormous scope of the tasks performed in the logistics
area. I hope the discussions bring about a better understanding of the
fact that logistics support is a major portion of most large development
projects. Logistics support, in fact, is a major cause of the success
or failure of many undertakings."
Background
James D. Baker and Frank Eichstadt of SPACEHAB wrote, in 2005:
The United States space exploration goals expressed in January 2004 call for the retirement of the Space Shuttle program following completion of International Space Station
(ISS) construction. Since the Shuttle is instrumental in transporting
large quantities of cargo to and from the ISS, this functional
capability must be preserved to ensure ongoing station operations in a
post-Shuttle era. Fulfilling ongoing cargo transport requirements to the
ISS is a prime opportunity for NASA to reduce costs and preserve and
repurpose the unique and limited Shuttle resource by acquiring cargo
transportation services commercially. Further, implementing such a
service prior to retirement of the Shuttle reduces risk to the vehicle
and her crews by eliminating their use for routine cargo transport
missions while accelerating the readiness for alternative ISS-support
transportation.
In January 2004, President Bush directed NASA to begin an
initiative that focuses on exploration of the Moon, Mars, and beyond.
This initiative calls for the completion of International Space Station
(ISS) assembly by the end of the decade coincident with retirement of
the Space Shuttle.
Retirement of the Shuttle while ISS operations are still being
conducted results in reduced capability to supply ISS logistics
requirements. An examination of existing and planned logistics carriers
shows that there are deficiencies in both capacity and capability to
support ISS needs. SPACEHAB's
history of space station logistics delivery and existing ground
infrastructure coupled with NASA's mandate and documented intent to
acquire commercial space systems and services when possible has led
SPACEHAB to develop a versatile and affordable cargo transport service
for ISS.
Sustainable space exploration is impossible without appropriate
supply chain management and unlike Apollo, future exploration will have
to rely on a complex supply network on the ground and in space. The
primary goal of this project is to develop a comprehensive supply chain
management framework and planning tool for space logistics. The eventual
integrated space logistics framework will encompass terrestrial
movement of material and information, transfer to launch sites, integration of payload onto launch vehicles and launch to Low Earth Orbit,
in-space and planetary transfer, and planetary surface logistics. The
MIT-led interplanetary supply chain management model will take a
four-phase development approach:
1. Review of supply chain management lessons learned from
Earth-based commercial and military projects, including naval submarine
and arctic logistics
2. Space logistics network analyses based on modeling Earth-Moon-Mars orbits and expected landing-exploration sites
3. Demand/supply modeling that embraces uncertainty in demand, cargo mix, costs, and supply chain disruptions
4. Development of an interplanetary supply chain architecture.
Examples of supply classes
Among the supply classes identified by the MIT Space Logistics Center:
Propellants and Fuels
Crew Provisions and Operations
Maintenance and Upkeep
Stowage and Restraint
Waste and Disposal
Habitation and Infrastructure
Transportation and Carriers
Miscellaneous
In the category of space transportation for ISS Support, one might list:
A
snapshot of the logistics of a single space facility, the International
Space Station, was provided in 2005 via a comprehensive study done by
James Baker and Frank Eichstadt. This article section makes extensive reference to that study.
However, in 2004, it was already anticipated that the European Automated Transfer Vehicle (ATV) and Japanese H-IIA Transfer Vehicle (HTV) would be introduced into service before the end of ISS Assembly.
As of 2004, the US Shuttle transported the majority of the pressurized
and unpressurized cargo and provides virtually all of the recoverable down mass capability (the capability of non-destructive reentry of cargo).
Cargo vehicle capabilities
Baker and Eichstadt also wrote, in 2005:
An understanding of the future ISS cargo requirements is
necessary to size a commercial cargo vehicle designed to replace the
Shuttle's capabilities and capacities and augment currently planned
alternative vehicles. Accurate estimates of ISS cargo transfer
requirements are difficult to establish due to ongoing changes in
logistics requirements, crew tending levels, vehicle availabilities, and
the evolving role the ISS will play in NASA's space exploration and
research goals.
An increased unpressurized cargo delivery requirement is shown
during the years 2007–2010. This increased rate is a result of a current
plan to preposition unpressurized spares on the ISS prior to Shuttle
retirement. Provision of a commercial cargo carrier capable of
transporting unpressurized spares to supplement the Shuttle eliminates
the prepositioning requirement and aligns the estimated averages during
2007–2010 to approximately 24,000 kg for pressurized cargo and 6800 kg
for unpressurized cargo. Considering the delivery capability of the
remaining systems after the Shuttle is retired yields.
Retirement of the Shuttle and reliance on the Progress, ATV, and HTV
for ISS logistics will result in no significant recoverable down-mass
capability. Further, no evidence suggests that any of these cargo
transport systems can increase production and launch rates to cover the
cargo delivery deficiency.
Commercial opportunity
Baker and Eichstadt also wrote, in 2005:
In addition to ISS support deficiencies, alternative
opportunities for a commercial cargo transport system exist. The
retirement of the Shuttle will also result in an inability to conduct
Low Earth Orbit (LEO) research independent of the ISS. A commercial
payload service could serve as a free-flying research platform to
fulfill this need. As logistics support requirements for NASA's space
exploration initiative emerge, existing commercial system can be
employed.
Finally, nascent interest in the development of non-government
commercial space stations must take resupply issues into consideration.
Such considerations will undoubtedly be subjected to a make/buy
analysis. Existing systems which have amortized their development costs
across multiple government and non-government programs should favor a
“buy” decision by commercial space station operators. As these markets
arise, commercial companies will be in a position to provide logistics
services at a fraction of the cost of government-developed systems. The
resulting economies of scale will benefit both markets. This conclusion
was reached by a Price-Waterhouse study chartered by NASA in 1991.
The study concluded that the value of SPACEHAB's flight-asset-based
commercial module service with an estimated net-present-value of $160
million would have cost the US government over $1 billion to develop and
operate using standard cost plus contracting. SPACEHAB's commercial
operations and developments (such as the Integrated Cargo Carrier) since
1991 represent further cost savings over government-owned and operated
systems.
Commercial companies are more likely to efficiently invest
private capital in service enhancements, assured continued availability,
and enhanced service capability. This tendency, commonplace in
non-aerospace applications, has been demonstrated by SPACEHAB in the
commercial space systems market via continued module enhancements and
introduction of new logistics carriers.
Shortfalls in ISS cargo transport capacity, emerging
opportunities, and experience gained from SPACEHAB's existing ground and
flight operations have encouraged development of Commercial Payload
Service (CPS). As a commercially developed system, SPACEHAB recognizes
that to optimize its capability and affordability requires that certain
approaches in system development and operations be taken.
The first approach levies moderate requirements on the system.
Introducing fundamental capabilities on the front end and scarring for
enhanced capabilities later reduces cost to launch and shortens
development time.
The second one is the utilization of existing technology and
capabilities, where appropriate. A typical feature of NASA programs is
the continual reach for newly developed technologies. While attractive
from a technical advancement perspective, this quest is expensive and
often fails to create operational capabilities. A commercially developed
cargo module will maximize the use of existing technologies (off the
shelf where possible) and seek technical advances only where system
requirements or market conditions drive the need for such advances.
Additionally, costs associated with the development of spacecraft are
not limited to those associated with the vehicle systems. Significant
costs associated with the infrastructure must also be considered.
SPACEHAB's existing logistics and vehicle processing facilities
co-located with the Eastern launch range and at the Sea Launch
facilities enable avoidance of significant system development costs.
Finally, SPACEHAB has realized cost and schedule reductions by
employing commercial processes instead of Government processes. As a
result, SPACEHAB's mission integration template for a Shuttle-based
carrier is 14 months, compared to 22 months for a similar Shuttle-based
Multi-Purpose Logistics Module (MPLM).
Rack transfer capability
Baker and Eichstadt also wrote, in 2005:
The ISS utilizes the International Standard Payload Rack
(ISPR) as the primary payload and experiment accommodations structure
in all US operated modules. Transferring ISPRs onto and off the ISS
requires passage through the hatch only found at the Common Berthing
Mechanism (CBM) berthing locations. The diameter of the CBM combined
with ISPR proportions typically drives cargo vehicle diameters to sizes
only accommodated by 5 m payload fairings launched on Evolved Expendable
Launch Vehicles (EELV).
Recoverable reentry–pressurized payloads
Baker and Eichstadt also wrote, in 2005:
The Russian Progress vehicle has long served as a cargo vehicle
which, upon departing a space station, destructively reenters the
atmosphere destroying all “cargo” on board. This approach works very
effectively for removing unwanted mass from a space station. However,
NASA has indicated that the return of payloads from the ISS is highly
desirable [5]. Therefore, a commercial system must examine the
implications of including a pressurized payload return capability either
in the initial design or as an enhanced feature of the service to be
introduced in the future. Providing such capability requires the
incorporation of thermal protection subsystem, deorbit targeting
subsystems, landing recovery subsystems, ground recovery infrastructure,
and FAA licensure. The recovery of unpressurized payloads presents
unique challenges associated with the exposed nature of unpressurized
carriers. To implement a recoverable reentry system for unpressurized
payloads requires the development of an encapsulation system.
Encapsulation activities must either occur autonomously prior to reentry
or as a part of the operations associated with loading the
unpressurized cargo carrier with return cargo. In either case,
additional cost associated with spacecraft systems or increased
operational requirements will be higher than simply loading and
departing a pressurized carrier for a destructive reentry.
Mixed manifest capability
Baker and Eichstadt also wrote, in 2005:
Typically, the avoidance of point solutions provides flexibility
for a given system to provide variable capabilities. Designing a cargo
carrier that mixes pressurized and unpressurized systems can lead to
increased cost if all associated cargo accommodations must be flown on
every flight. To avoid unnecessary costs associated with designing and
flying structure that accommodates fixed relative capacities of all
types of payloads, a modular approach is taken for CPS. Anticipated
cargo transport requirements for ISS after the Shuttle is retired
indicate that dedicated pressurized and unpressurized missions can
support the ISS up-mass requirements. Utilizing common base features
(i.e. service module, docking system, etc.) and modularizing the
pressurized and unpressurized carrier elements of the spacecraft assures
flexibility while avoiding point solutions.
Propellant transfer
Baker and Eichstadt also wrote, in 2005:
The Russian Segment of the ISS (RSOS) has the capability via the
probe and cone docking mechanisms to support propellant transfer.
Incorporation of propellant transfer capability introduces international
issues requiring the coordination of multiple corporate and
governmental organizations. Since ISS propellant requirements are
adequately provided for by the Russian Progress and ESA ATV, costs
associated with incorporating these features can be avoided. However,
the CPS’ modular nature coupled with the inherent capability of selected
subsystems enables economical alternatives to propellant transfer
should ISS needs require.
Indirect costs considered in developing the CPS architecture include licensing requirements associated with International Traffic in Arms Regulations (ITAR) and the Federal Aviation Administration
(FAA) commercial launch and entry licensing requirements. ITAR
licensing drives careful selection of the vehicle subsystem suppliers.
Any utilization or manufacturing of spacecraft subsystems by non-US
entities can only be implemented once the appropriate Department of
State and/or Commerce approvals are in place. FAA licensing requirements
necessitate careful selection of the launch and landing sites. Vehicles
developed by a US organized corporation, even if launched in another
country, require review of the vehicle system, operations, and safety
program by the FAA to ensure that risks to people and property are
within acceptable limits.
Downmass
While significant focus of space logistics is on upmass, or payload mass carried up to orbit from Earth, space station operations also have significant downmass requirements.
Returning cargo from low-Earth orbit to Earth is known as transporting downmass, the total logistics payload mass that is returned from space to the surface of the Earth for subsequent use or analysis.
Downmass logistics are important aspects of research and manufacturing work that occurs in orbital space facilities.
For the International Space Station,
there have been periods of time when downmass capability was severely
restricted. For example, for approximately ten months from the time of
the retirement of the Space Shuttle following the STS-135
mission in July 2011—and the resultant loss of the Space Shuttle's
ability to return payload mass—an increasing concern became returning
downmass cargo from low-Earth orbit to Earth for subsequent use or analysis.
During this period of time, of the four space vehicles capable of
reaching and delivering cargo to the International Space Station, only
the Russian Soyuz vehicle could return even a very small cargo payload to Earth. The Soyuz cargo downmass capability was limited as the entire space capsule was filled to capacity with the three ISS crew members who return on each Soyuz return. At the time none of the remaining cargo resupply vehicles — the Russian Space AgencyProgress, the European Space Agency (ESA) ATV, the Japan Aerospace Exploration Agency (JAXA) HTV — could return any downmass cargo for terrestrial use or examination.
After 2012, with the successful berthing of the commercially contractedSpaceXDragon during the Dragon C2+ mission in May 2012, and the initiation of operational cargo flights in October 2012,[12]
downmass capability from the ISS is now 3,000 kilograms (6,600 lb) per
Dragon flight, a service that is provided by the Dragon cargo capsule
routinely. An return capsule tested in 2018 called the HTV Small Re-entry Capsule (HSRC) could be used in future HTV flights. The HSRC has a maximum downmass capability of 20 kilograms (44 lb).
A view of the Earth's atmosphere with the Moon beyond
Aerospace is the human effort in science, engineering, and business to fly in the atmosphere of Earth (aeronautics) and surrounding space (astronautics). Aerospace organizations research, design, manufacture, operate, or maintain aircraft or spacecraft. Aerospace activity is very diverse, with a multitude of commercial, industrial and military applications.
Aerospace is not the same as airspace, which is the physical air space directly above a location on the ground. The beginning of space and the ending of the air
is considered as 100 km above the ground according to the physical
explanation that the air pressure is too low for a lifting body to
generate meaningful lift force without exceeding orbital velocity.
Modern aerospace began with Engineer George Cayley
in 1799. Cayley proposed an aircraft with a "fixed wing and a
horizontal and vertical tail," defining characteristics of the modern
airplane.
The 19th century saw the creation of the Aeronautical Society of Great Britain (1866), the American Rocketry Society, and the Institute of Aeronautical Sciences, all of which made aeronautics a more serious scientific discipline. Airmen like Otto Lilienthal, who introduced camberedairfoils in 1891, used gliders to analyze aerodynamic forces. The Wright brothers were interested in Lilienthal's work and read several of his publications. They also found inspiration in Octave Chanute, an airman and the author of Progress in Flying Machines (1894).
It was the preliminary work of Cayley, Lilienthal, Chanute, and other
early aerospace engineers that brought about the first powered sustained
flight at Kitty Hawk, North Carolina on December 17, 1903, by the
Wright brothers.
War and science fiction inspired scientists and engineers like Konstantin Tsiolkovsky and Wernher von Braun to achieve flight beyond the atmosphere. World War II inspired Wernher von Braun to create the V1 and V2 rockets.
The launch of Sputnik 1 in October 1957 started the Space Age, and on July 20, 1969 Apollo 11 achieved the first manned moon landing. In April 1981, the Space Shuttle Columbia launched, the start of regular manned access to orbital space. A sustained human presence in orbital space started with "Mir" in 1986 and is continued by the "International Space Station". Space commercialization and space tourism are more recent features of aerospace.
Manufacturing
Aerospace manufacturing is a high-technology industry that produces
"aircraft, guided missiles, space vehicles, aircraft engines, propulsion
units, and related parts". Most of the industry is geared toward governmental work. For each original equipment manufacturer (OEM), the US government has assigned a Commercial and Government Entity (CAGE) code.
These codes help to identify each manufacturer, repair facilities, and
other critical aftermarket vendors in the aerospace industry.
In the United States, the Department of Defense and the National Aeronautics and Space Administration
(NASA) are the two largest consumers of aerospace technology and
products. Others include the very large airline industry. The aerospace
industry employed 472,000 wage and salary workers in 2006. Most of those jobs were in Washington state and in California, with Missouri, New York and Texas also being important. The leading aerospace manufacturers in the U.S. are Boeing, United Technologies Corporation, SpaceX, Northrop Grumman and Lockheed Martin.
These manufacturers are facing an increasing labor shortage as skilled
U.S. workers age and retire. Apprenticeship programs such as the
Aerospace Joint Apprenticeship Council (AJAC) work in collaboration with
Washington state aerospace employers and community colleges to train
new manufacturing employees to keep the industry supplied.
In the European Union, aerospace companies such as EADS, BAE Systems, Thales, Dassault, Saab AB and Leonardo S.p.A. (formerly Finmeccnica) account for a large share of the global aerospace industry and research effort, with the European Space Agency as one of the largest consumers of aerospace technology and products.
The United Kingdom formerly attempted to maintain its own large aerospace industry, making its own airliners
and warplanes, but it has largely turned its lot over to cooperative
efforts with continental companies, and it has turned into a large
import customer, too, from countries such as the United States. However,
the UK has a very active aerospace sector, including the second largest
defence contractor in the world, BAE Systems,
supplying fully assembled aircraft, aircraft components, sub-assemblies
and sub-systems to other manufacturers, both in Europe and all over the
world.
Canada has formerly manufactured some of its own designs for jet warplanes, etc. (e.g. the CF-100
fighter), but for some decades, it has relied on imports from the
United States and Europe to fill these needs. However Canada still
manufactures some military aircraft although they are generally not
combat capable. Another notable example was the late 1950s development
of the Avro Canada CF-105 Arrow, a supersonic fighter-interceptor that was cancelled in 1959 a highly controversial decision.
France has continued to make its own warplanes for its air force
and navy, and Sweden continues to make its own warplanes for the Swedish
Air Force—especially in support of its position as a neutral country. (See Saab AB.) Other European countries either team up in making fighters (such as the Panavia Tornado and the Eurofighter Typhoon), or else to import them from the United States.
In the People's Republic of China, Beijing, Xi'an, Chengdu, Shanghai, Shenyang and Nanchang
are major research and manufacture centers of the aerospace industry.
China has developed an extensive capability to design, test and produce
military aircraft, missiles and space vehicles. Despite the cancellation
in 1983 of the experimental Shanghai Y-10, China is still developing its civil aerospace industry.
The aircraft parts industry
was born out of the sale of second-hand or used aircraft parts from the
aerospace manufacture sector. Within the United States there is a
specific process that parts brokers or resellers must follow. This
includes leveraging a certified repair station to overhaul
and "tag" a part. This certification guarantees that a part was
repaired or overhauled to meet OEM specifications. Once a part is
overhauled its value is determined from the supply and demand of the
aerospace market. When an airline has an aircraft on the ground,
the part that the airline requires to get the plane back into service
becomes invaluable. This can drive the market for specific parts.
There are several online marketplaces that assist with the commodity
selling of aircraft parts.
In the aerospaces & defense industry, a lot of consolidation
has appeared over the last couple of decades. Between 1988 and 2011,
worldwide more than 6,068 mergers & acquisitions with a total known value of 678 bil. USD have been announced. The largest transactions have been:
The 1927 large Propeller Research Tunnel at NACA Langley confirmed that the landing gear was a major source of drag, in 1930 the Boeing Monomail featured a retractable gear.
The flush rivet displaced the domed rivet in the 1930s and pneumatic rivet guns work in combination with a heavy reaction bucking bar; not depending on plastic deformation, specialist rivets were developed to improve fatigue life as shear fasteners like the Hi-Lok, threaded pins tightened until a collar breaks off with enough torque.
At the end of World War I, piston engine power could be boosted by
compressing intake air with a compressor, also compensating for
decreasing air density with altitude, improved with 1930s turbochargers for the Boeing B-17 and the first pressurized airliners.
As US airlines were interested in high-altitude flying in the mid-1930s, the Lockheed XC-35 with a pressurized cabin was tested in 1937 and the Boeing 307 Stratoliner was developed as the first pressurized airliner.
In 1933, Plexiglas,
a transparent Acrylic plastic, was introduced in Germany and shortly
before World War II, was first used for aircraft windshields as it is
lighter than glass, and the bubble canopy improved fighter pilots
visibility.
In January 1930, Royal Air Force pilot and engineer Frank Whittle filed a patent for a gas turbine aircraft engine with an inlet, compressor, combustor, turbine and nozzle, while an independent turbojet was developed by researcher Hans von Ohain in Germany; both engines ran within weeks in early 1937 and the Heinkel HeS 3-propelled Heinkel He 178 experimental aircraft made its first flight on Aug 27, 1939 while the Whittle W.1-powered Gloster E.28/39 prototype flew on May 15, 1941.
In the early 1940s, British Hurricane and Spitfire pilots wore g-suits to prevent G-LOC due to blood pooling in the lower body in high g situations; Mayo Clinic researchers developed air-filled bladders to replace water-filled bladders and in 1943 the US military began using pressure suits from the David Clark Company.
The modern ejection seat
was developed during World War II, a seat on rails ejected by rockets
before deploying a parachute, which could have been enhanced by the USAF
in the late 1960s as a turbojet-powered autogyro with 50 nm of range,
the Kaman KSA-100 SAVER.
In 1942, numerical control machining was conceived by machinist John T. Parsons
to cut complex structures from solid blocks of alloy, rather than
assembling them, improving quality, reducing weight, and saving time and
cost to produce bulkheads or wing skins.
The UK Miles M.52 supersonic aircraft was to have an afterburner, augmenting a turbojet thrust by burning additional fuel in the nozzle, but was cancelled in 1946.
To board an airliner, jet bridges are more accessible, comfortable and efficient than climbing the stairs.
In the 1950s, to improve thrust and fuel efficiency, the jet engine
airflow was divided into a core stream and a bypass stream with a lower
velocity for better propulsive efficiency: the first was the Rolls-Royce Conway with a 0.3 BPR on the Boeing 707 in 1960, followed by the Pratt & Whitney JT3D with a 1.5 BPR and, derived from the J79, the General Electric CJ805 powered the Convair 990 with a 28% lower cruise fuel burn; bypass ratio improved to the 9.3 BPR Rolls-Royce Trent XWB, the 10:1 BPR GE9X and the Pratt & Whitney GTF with high-pressure ratio cores.
Functional safety
Functional
safety relates to a part of the general safety of a system or a piece
of equipment. It implies that the system or equipment can be operated
properly and without causing any danger, risk, damage or injury.
Functional safety is crucial in the aerospace industry, which
allows no compromises or negligence. In this respect, supervisory
bodies, such as the European Aviation Safety Agency (EASA
),
regulate the aerospace market with strict certification standards. This
is meant to reach and ensure the highest possible level of safety. The
standards AS 9100 in America, EN 9100 on the European market or JISQ
9100 in Asia particularly address the aerospace and aviation industry.
These are standards applying to the functional safety of aerospace
vehicles. Some companies are therefore specialized in the certification,
inspection verification and testing of the vehicles and spare parts to
ensure and attest compliance with the appropriate regulations.
Spinoffs
Spinoffs
refer to any technology that is a direct result of coding or products
created by NASA and redesigned for an alternate purpose.
These technological advancements are one of the primary results of the
aerospace industry, with $5.2 billion worth of revenue generated by
spinoff technology, including computers and cellular devices.
These spinoffs have applications in a variety of different fields
including medicine, transportation, energy, consumer goods, public
safety and more.
NASA publishes an annual report called “Spinoffs”, regarding many of
the specific products and benefits to the aforementioned areas in an
effort to highlight some of the ways funding is put to use.
For example, in the most recent edition of this publication, “Spinoffs
2015”, endoscopes are featured as one of the medical derivations of
aerospace achievement.
This device enables more precise and subsequently cost-effective
neurosurgery by reducing complications through a minimally invasive
procedure that abbreviates hospitalization.
Space launch is the earliest part of a flight that reaches space. Space launch involves liftoff, when a rocket or other space launch vehicle leaves the ground, floating ship or midair aircraft at the start of a flight. Liftoff is of two main types: rocket launch (the current conventional method), and non-rocket spacelaunch (where other forms of propulsion are employed, including airbreathing jet engines or other kinds).
Issues with reaching space
Definition of space
Space
has no physical edge to it as the atmospheric pressure gradually
reduces with altitude; instead, the edge of space is defined by
convention, often the Kármán line of 100 km. Other definitions have been created as well. In the US for example space has been defined as 50 miles.
Energy
Therefore, by definition for spaceflight to occur, sufficient altitude is necessary. This implies a minimum gravitational potential energy needs to be overcome: for the Kármán line this is approximately 1 MJ/kg.
W=mgh, m=1 kg, g=9.82 m/s2, h=105m.
W=1*9.82*105≈106J/kg=1MJ/kg.
In practice, a higher energy than this is needed to be expended
due to losses such as airdrag, propulsive efficiency, cycle efficiency
of engines that are employed and gravity drag.
In the past fifty years spaceflight has usually meant remaining
in space for a period of time, rather than going up and immediately
falling back to earth. This entails orbit, which is mostly a matter of
velocity, not altitude, although that does not mean air friction and
relevant altitudes in relation to that and orbit don't have to be taken
into account. At much, much higher altitudes than many orbital ones
maintained by satellites, altitude begins to become a larger and larger
factor and speed a lesser one. At lower altitudes, due to the high speed
required to remain in orbit, air friction is a very important
consideration affecting satellites, much more than in the popular image
of space. At even lower altitudes, balloons, with no forward velocity,
can serve many of the roles satellites play.
G-forces
Many cargoes, particularly humans have a limiting g-force
that they can survive. For humans this is about 3-6 g. Some launchers
such as gun launchers would give accelerations in the hundred or
thousands of g and thus are completely unsuitable.
Reliability
Launchers vary with respect to their reliability for achieving the mission.
Safety
Safety is
the probability of causing injury or loss of life. Unreliable launchers
are not necessarily unsafe, whereas reliable launchers are usually, but
not invariably safe.
Apart from catastrophic failure of the launch vehicle itself other safety hazards include depressurisation, and the Van Allen radiation belts which preclude orbits which spend long periods within them.
The selection of flight profiles that yield the greatest
performance plays a substantial role in the preliminary design of flight
vehicles, since the use of ad-hoc profile or control policies to
evaluate competing configurations may inappropriately penalize the
performance of one configuration over another. Thus, to guarantee the
selection of the best vehicle design, it is important to optimize the
profile and control policy for each configuration early in the design
process.
For example, for tactical missiles, the flight profiles are determined by the thrust and load factor (lift) histories. These histories can be controlled by a number of means including such techniques as using an angle of attack
command history or an altitude/downrange schedule that the missile must
follow. Each combination of missile design factors, desired missile
performance, and system constraints results in a new set of optimal
control parameters.
Sustained spaceflight
Suborbital launch
Sub-orbital space flight is any space launch that reaches space
without doing a full orbit around the planet, and requires a maximum
speed of around 1 km/s just to reach space, and up to 7 km/s for longer
distance such as an intercontinental space flight. An example of a
sub-orbital flight would be a ballistic missile, or future tourist
flight such as Virgin Galactic, or an intercontinental transport flight like SpaceLiner.
Any space launch without an orbit-optimization correction to achieve a
stable orbit will result in a suborbital space flight, unless there is
sufficient thrust to leave orbit completely.
Orbital launch
In addition, if orbit is required, then a much greater amount of
energy must be generated in order to give the craft some sideways speed.
The speed that must be achieved depends on the altitude of the orbit –
less speed is needed at high altitude. However, after allowing for the
extra potential energy of being at higher altitudes, overall more energy
is used reaching higher orbits than lower ones.
The speed needed to maintain an orbit near the Earth's surface
corresponds to a sideways speed of about 7.8 km/s (17,400 mph), an
energy of about 30MJ/kg. This is several times the energy per kg of
practical rocket propellant mixes.
Gaining the kinetic energy is awkward as the airdrag tends to
slow the spacecraft, so rocket-powered spacecraft generally fly a
compromise trajectory that leaves the thickest part of the atmosphere
very early on, and then fly on for example, a Hohmann transfer orbit
to reach the particular orbit that is required. This minimises the
airdrag as well as minimising the time that the vehicle spends holding
itself up. Airdrag is a significant issue with essentially all proposed
and current launch systems, although usually less so than the difficulty
of obtaining enough kinetic energy to simply reach orbit at all.
Escape velocity
If the Earth's gravity is to be overcome entirely then sufficient
energy must be obtained by a spacecraft to exceed the depth of the
gravity potential energy well. Once this has occurred, provided the
energy is not lost in any non-conservative way, then the vehicle will
leave the influence of the Earth. The depth of the potential well
depends on the vehicle's position, and the energy depends on the
vehicle's speed. If the kinetic energy exceeds the potential energy then
escape occurs. At the Earth's surface this occurs at a speed of
11.2 km/s (25,000 mph), but in practice a much higher speed is needed
due to airdrag.
Types of space launch
Rocket launch
Rocket launch is the only current way to reach space. In some cases
an airbreathing (jet engine) first stage has been used as well.
Non-rocket launch
Non-rocket space launch is a launch into space where some or all of the needed speed and altitude are provided by something other than expendable rockets. A number of alternatives to expendable rockets have been proposed. In some systems such as Skyhooks, rocket sled launch, and air launch, a rocket is used to reach orbit, but it is only part of the system.
