Thursday 20 June 2013

SpaceShipOne

SpaceShipOne Experimental:-

SpaceShipOne is a suborbital air-launched spaceplane that completed
the first manned private spaceflight in 2004. That same year, it won
the US$10 million Ansari X Prize and was immediately retired from
active service. Its mother ship was named "White Knight". Both craft
were developed and flown by Mojave Aerospace Ventures, which was a
joint venture between Paul Allen and Scaled Composites, Burt Rutan's
aviation company. Allen provided the funding of approximately US$25
million.
   Rutan has indicated that ideas about the project began as early as
1994 and the full-time development cycle time to the 2004
accomplishments was about three years. The vehicle first achieved
supersonic flight on December 17, 2003, which was also the
one-hundredth anniversary of the Wright Brothers' historic first
powered flight. SpaceShipOne's first official spaceflight, known as
flight 15P, was piloted by Mike Melvill. A few days before that
flight, the Mojave Air and Space Port was the first commercial
spaceport licensed in the United States. A few hours after that
flight, Melvill became the first licensed U.S. commercial astronaut.
The overall project name was "Tier One" which has evolved into Tier 1b
with a goal of taking a successor ship's first passengers into space
within the next few years.

Contents:-

1. Development and winning the X Prize
 1.1 Flights
 1.2 Astronauts
2. Retirement
3. Replicas
4. Subsequent spacecraft
5. Specifications


1.Development and winning the X Prize:-

SpaceShipOne was developed by Mojave Aerospace Ventures (a joint
venture between Paul Allen and Scaled Composites, Burt Rutan's
aviation company, in their Tier One program), without government
funding. On June 21, 2004, it made the first privately funded human
spaceflight. On October 4, it won the US$10 million Ansari X Prize, by
reaching 100 kilometers in altitude twice in a two-week period with
the equivalent of three people on board and with no more than ten
percent of the non-fuel weight of the spacecraft replaced between
flights. Development costs were estimated to be US$25 million, funded
completely by Paul Allen.
  During its test programme, SpaceShipOne set a number of important
"firsts", including first privately funded aircraft to exceed Mach 2
and Mach 3, first privately funded manned spacecraft to exceed 100km
altitude, and first privately funded reusable manned
spacecraft.SpaceShipOne is an experimental air-launched rocket-powered
aircraft with suborbital flight capability that uses a hybrid rocket
motor. The design features a unique "feathering" atmospheric reentry
system where the rear half of the wing and the twin tail booms folded
upward along a hinge running the length of the wing; this increased
drag while remaining stable. The achievements of SpaceShipOne are more
comparable to the X-15 than orbiting spacecraft like the Space
Shuttle. Accelerating a spacecraft to orbital speed requires more than
60 times as much energy as accelerating it to Mach 3. It would also
require an elaborate heat shield to safely dissipate that energy
during re-entry.

1.1.Flights:-

All of the flights of SpaceShipOne were from the Mojave Airport
Civilian Flight Test Center. Flights were numbered, starting with
flight 01 on May 20, 2003. One or two letters are appended to the
number to indicate the type of mission. An appended C indicates that
the flight was a captive carry, G indicates an unpowered glide, and P
indicates a powered flight. If the actual flight differs in category
from the intended flight, two letters are appended: the first
indicating the intended mission and the second the mission actually
performed.

1.2.Astronauts:-

The SpaceShipOne pilots came from a variety of aerospace backgrounds.
Mike Melvill is a test pilot, Brian Binnie is a former Navy pilot, and
Doug Shane and Peter Siebold are engineers at Scaled Composites. They
qualified to fly SpaceShipOne by training on the Tier One flight
simulator and in White Knight and other Scaled Composites aircraft.


2.Retirement:-

SpaceShipOne's spaceflights were watched by large crowds at Mojave
Spaceport. A fourth suborbital flight, Flight 18P, was originally
scheduled for October 13, 2004. However, Burt Rutan decided not to
risk damage to the historic craft, and cancelled it and all future
flights.
On July 25, 2005 SpaceShipOne was taken to the Oshkosh Airshow in
Oshkosh, Wisconsin. After the airshow, Mike Melvill and crew flew the
White Knight, carrying SpaceShipOne, to Wright-Patterson Air Force
Base in Dayton, Ohio, where Melvill spoke to a group of about 300
military and civilian personnel. Later in the evening, Melvill gave a
presentation at the Dayton Engineers Club, entitled "Some Experiments
in Space Flight", in honor of Wilbur Wright's now-famous presentation
to the American Society of Mechanical Engineers in 1901 entitled "Some
Experiments in Flight." The White Knight then transported SpaceShipOne
to the Smithsonian Institution's National Air and Space Museum to be
put on display. It was unveiled on Wednesday October 5, 2005 in the
Milestones of Flight gallery and is now on display to the public in
the main atrium with the Spirit of St. Louis, the Bell X-1, the Wright
Flyer, and the Apollo 11 command module Columbia.
Commander Brian Binnie donated the flight suit worn during his Ansari
X Prize-winning flight to an auction benefitting Seattle's Museum of
Flight. Entertainer and charity auctioneer Fred Northup, Jr. purchased
the flight suit, and subsequently announced his intention to display
it on loan at the museum's new Charles Simonyi Space Gallery.
SpaceShipOne became a popular model rocket in 2004. A piece of
SpaceShipOne's carbon fiber material was launched aboard the New
Horizons mission to Pluto in 2006.

3.Replicas:-

A year after its appearance in the Oshkosh Airventure airshow, the
Experimental Aircraft Association featured a full-scale replica of the
spacecraft in a wing of its museum which housed other creations of
Burt Rutan. Using the same fiberglass molds as the original, it was so
exact in its replication — despite not having any doors or interior —
that it was dubbed "Serial 2 Scaled" by Scaled Composites. Each and
every painstaking detail in its appearance was matched, down to the
N328KF registration number on its fuselage. It is so precise that,
during a video presentation held every hour in the museum, it can
display the two different modes of its 'feathering' ability, albeit
through the aid of pulleys and wires (there is no machinery in the
replica).
Another full-scale replica of SpaceShipOne hangs in the rotunda of the
William Thomas Terminal at Meadows Field Airport in Bakersfield, a
third is on display in the Mojave Spaceport's Legacy Park alongside
the original Roton Atmospheric Test Vehicle[citation needed] a fourth
is at Paul Allen's Flying Heritage Museum at Paine Field in Everett.,
and a fifth is on display in Google's Mountain View Campus.

Subsequent spacecraft:-

With the success of Tier One meeting its project goals, a successor
project started in 2004 was Tier 1b. The successor ships are named
SpaceShipTwo and White Knight Two. The name of the joint venture
between Virgin Group and Scaled Composites is called The Spaceship
Company, with a goal of carrying passengers under the name Virgin
Galactic, a spaceliner with an initial target of a commercial fleet of
five spacecraft.
       In August 2005, Virgin Galactic stated that if the upcoming
suborbital service with SpaceShipTwo is successful, the follow-up will
be known as SpaceShipThree.

5.Specifications:-

General characteristics:-

.Crew: one, pilot
.Capacity: 2 passengers
.Length: 28 ft (8.53 m) ()
.Wingspan: 16 ft 5 in (8.05 m)
.Height: ()
.Wing area: 161.4 ft² (15 m²)
.Empty weight: 2,640 lb (1,200 kg)
.Loaded weight: 7,920 lb (3,600 kg)
.Powerplant: 1 × N2O/HTPB SpaceDev Hybrid rocket motor, 7,500 kgf (74 kN)
.Isp: 250 s (2450 Ns/kg)
.Burn time: 87 seconds
.Aspect Ratio: 1.6

Performance:-
.Maximum speed: Mach 3.09 (2,170 mph, 3,518 km/h)
.Range: 35 nm (40 mi, 65 km)
.Service ceiling: 367,360 ft (112,000 m)
.Rate of climb: 82,000 ft/min (416.6 m/s)
.Wing loading: 49.07 lb/ft² (240 kg/m²)
.Thrust/weight: 2.08


keywords of SpaceShipOne Experimental:-

Space Year 1
Space Ship 1
Tier 1 Status
One Space
Tier 1
Tier 1 Supplier
Scaled Composites
Flights into Space


Rocket-powered aircraft & glider:-

A rocket-powered aircraft or rocket plane is an aircraft that uses a
rocket for propulsion, sometimes in addition to airbreathing jet
engines. Rocket planes can achieve much higher speeds than similarly
sized jet aircraft, but typically for at most a few minutes of powered
operation, followed by a glide. Unhindered by the need for oxygen from
the atmosphere they are suitable for very high altitude flight. They
are also capable of delivering much higher acceleration and shorter
takeoffs.
Rockets have been used simply to assist the main propulsion in the
form of Jet Assisted Take Off (JATO) also known as "Rocket Assisted
Take Off" (RATO). Not all rocket planes are of the conventional
takeoff like "normal" aircraft. Some types have been air-launched from
another plane, while other types have taken off vertically - nose in
the air and tail to the ground ("tail-sitters"). It is also possible,
that rocket planes launch vertically without changing their
orientation.
Because of the heavy propellant use and the various practical
difficulties of operating rockets, the majority of rocket planes have
been built for experimental use, as interceptor fighters and space
aircraft.


Contents:-

1. History
 1.1 World War II
 1.2 Cold War era
 1.3 Post Cold War era
 1.3.1 Planned rocket-powered aircra

1.History:-

Rocket-powered flight was pioneered in Germany. The first aircraft to
fly under rocket power was the Lippisch Ente, in 1928. The Ente had
previously been flown as a glider. The next year, in 1929, the Opel
RAK.1 became the first purpose-built rocket plane to fly.

1.1.World War II:-

The Heinkel He 176 was the world’s first aircraft to be propelled
solely by a liquid-fuelled rocket, making its first powered flight on
20 June 1939 with Erich Warsitz at the controls.
The first rocket planes ever to be mass-produced were the
Messerschmitt Me 163 in 1944, one of several German World War II
attempts at rocket-powered aircraft. Other German experimental
rocket-powered aircraft included the Bachem Ba 349 vertical takeoff
manned rocket interceptor aircraft and the Focke-Wulf Volksjäger. The
Silbervogel antipodal bomber was planned by the Germans late in World
War II, however later calculations showed that it would not have
worked, and would have been destroyed during reentry. The Japanese
also produced approximately 850 Yokosuka MXY7 Ohka rocket-powered
suicide attack aircraft in World War II.Other experimental aircraft
included the Russian Bereznyak-Isayev BI-1 that flew in 1942 while The
Northrop XP-79 began with rocket engines in its initial design.
     A rocket assisted P-51D Mustang was developed by North American
Aviation that could attain 515 mph. The engine ran on fumaric acid and
aniline, stored in two 75 gallon under wing drop tanks. The plane was
tested in flight in April 1945. The rocket engine could run for about
a minute.

1.2.Cold War era:-

In 1946 the rocket-powered Bell X-1 was the first aircraft to break
the speed of sound in level flight and the first of a seris of
NACA/NASA rocket-powered aircraft. The North American X-15 and X-15A2
designs were used for around a decade and eventually reached Mach 6.7
and over 100 km in altitude.
In the 1950s the British developed mixed power designs to cover the
performance gap that existed in then-current turbojet designs. The
rocket was the main engine for delivering the speed and height
required for high speed interception of high level bombers and the
turbojet gave increased fuel economy in other parts of flight, most
notably to make sure the aircraft was able to make a powered landing
rather than risking an unpredictable gliding return. The Saunders-Roe
SR.53 was a successful design and was due to be developed into
production when economics forced curtailment of most British aircraft
programmes in the late 1950s. The advancement of the turbojet engine
output, the advent of missiles, and advances in radar had made a
return to mixed power unnecessary.
The development of Soviet rockets and satellites was the driving force
behind the development of NASA's space program. In the early 1960s,
American research into the Boeing X-20 Dyna-Soar spaceplane was
cancelled due to lack of purpose; later the studies contributed to the
Space Shuttle, which in turn motivated the Russian Buran (spacecraft).
Another similar program was ISINGLASS which was to be a rocket plane
launched from a Boeing B-52 Stratofortress carrier, which was intended
to achieve Mach 22, but this was never funded. ISINGLASS was intended
to overfly the USSR. No images of the vehicle configuration have been
released.
The Lunar Landing Research Vehicle was a mixed powered vehicle- a jet
engine cancelled 5/6 of the force due to gravity, and the rocket power
was able to simulate the Apollo lunar lander.
Various versions of the Reaction Motors XLR11 rocket engine powered
the X-1 and X-15, but also the Martin Marietta X-24A, Martin Marietta
X-24B, Northrop HL-10, Northrop M2-F2, Northrop M2-F3, and the
Republic XF-91 Thunderceptor, either has a primary or axillary engine.

1.3.Post Cold War era:-

The EZ-Rocket research and test airplane was first flown in 2001.The
development of SpaceShipOne, first flown in 2003, and XCOR Aerospace's
EZ-Rocket, are some of the more recent rocket powered aircraft to be
developed.The Rocket Racing League has been in development to take
advantage of the popularity of the Ansari X-Prize.

Planned rocket-powered aircraft:-

1.Reaction Engines Skylon
2.Spaceship Two
3.Lynx rocketplane
4.ARES (martian rocketplane)


keywords of Rocket-powered aircraft & glider:-

Rocket-Propelled RC Glider
Radio Controlled Rocket Glider
Model Rocket Glider
RC Rocket Glider Kits
SR-71 Rocket Glider
RC Rocket Glider
Rocket Gliders
Boost Glider


High altitude:-

Altitude or height is defined based on the context in which it is used
(aviation, geometry, geographical survey, sport, and more). 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. Although the term altitude is commonly used to mean the
height above sea level of a location, in geography the term elevation
is often preferred for this usage.Vertical distance measurements in
the "down" direction are commonly referred to as depth.

Contents  :-

1. Altitude in aviation and in spaceflight
2. Altitude regions
3. High altitude and low air pressure
 3.1 Relation between temperature and altitude in Earth's atmosphere
 3.2 Effects of high altitude on humans
  3.2.1 Athletes
 3.3 Effect of altitude on animals
  3.3.1 Fish
  3.3.2 Rodents
  3.3.3 Birds

Altitude in aviation and in spaceflight:-

In aviation, the term altitude can have several meanings, and is
always qualified by either explicitly adding a modifier (e.g. "true
altitude"), or implicitly through the context of the communication.
Parties exchanging altitude information must be clear which definition
is being used.Aviation altitude is measured using either Mean Sea
Level (MSL) or local ground level (Above Ground Level, or AGL) as the
reference datum.Pressure altitude divided by 100 feet (30m) as the
flight level, and is used above the transition altitude (18,000 feet
(5,500 m) in the US, but may be as low as 3,000 feet (910 m) in other
jurisdictions); so when the altimeter reads 18,000 ft on the standard
pressure setting the aircraft is said to be at "Flight level 180".
When flying at a Flight Level, the altimeter is always set to standard
pressure (29.92 inHg / 1013.25 mbar).
       On the flight deck, the definitive instrument for measuring
altitude is the pressure altimeter, which is an aneroid barometer with
a front face indicating distance (feet or metres) instead of
atmospheric pressure.

2.Altitude regions:-

The Earth's atmosphere is divided into several altitude regions:-
.Troposphere — surface to 8,000 metres (5.0 mi) at the poles – 18,000
metres (11 mi) at the equator, ending at the
Tropopause.
.Stratosphere — Troposphere to 50 kilometres (31 mi)
.Mesosphere — Stratosphere to 85 kilometres (53 mi)
.Thermosphere — Mesosphere to 675 kilometres (419 mi)
.Exosphere — Thermosphere to 10,000 kilometres (6,200 mi)

3.High altitude and low air pressure:-

Regions on the Earth's surface (or in its atmosphere) that are high
above mean sea level are referred to as high altitude. High altitude
is sometimes defined to begin at 2,400 metres (8,000 ft) above sea
level.At high altitude, atmospheric pressure is lower than that at sea
level. This is due to two competing physical effects: gravity, which
causes the air to be as close as possible to the ground; and the heat
content of the air, which causes the molecules to bounce off each
other and expand.Because of the lower pressure, the air expands as it
rises, which causes it to cool. Thus, high altitude air is cold, which
causes a characteristic alpine climate. This climate dramatically
affects the ecology at high altitude.

3.1.Relation between temperature and altitude in Earth's atmosphere:-

The environmental lapse rate (ELR), is the rate of decrease of
temperature with altitude in the stationary atmosphere at a given time
and location. As an average, the International Civil Aviation
Organization (ICAO) defines an international standard atmosphere (ISA)
with a temperature lapse rate of 6.49 K(°C)/1,000 m (3.56 °F or 1.98
K(°C)/1,000 Ft) from sea level to 11 kilometres (36,000 ft). From 11
to 20 kilometres (36,000 to 66,000 ft), the constant temperature is
-56.5 °C (-69.7 °F), which is the lowest assumed temperature in the
ISA. The standard atmosphere contains no moisture. Unlike the
idealized ISA, the temperature of the actual atmosphere does not
always fall at a uniform rate with height. For example, there can be
an inversion layer in which the temperature increases with height.


3.2.Effects of high altitude on humans:-

Medicine recognizes that altitudes above 1,500 metres (4,900 ft) start
to affect humans, and extreme altitudes above 5,500–6,000 metres
(18,000–20,000 ft) cannot be permanently tolerated by humans.As the
altitude increases, atmospheric pressure decreases, which affects
humans by reducing the partial pressure of oxygen. The lack of oxygen
above 2,400 metres (8,000 ft) can cause serious illnesses such as
altitude sickness, high altitude pulmonary edema, and high altitude
cerebral edema. The higher the altitude, the more likely are serious
effects. The human body can adapt to high altitude by breathing
faster, having a higher heart rate, and adjusting its blood chemistry.
It can take days or weeks to adapt to high altitude. However, above
8,000 metres (26,000 ft), (in the "death zone"), the human body cannot
adapt and will eventually die.There is a significantly lower overall
mortality rate for permanent residents at higher altitudes.
Additionally, there is a dose response relationship between increasing
elevation and decreasing obesity prevalence in the United States.
However, people living at higher elevations have a statistically
significant higher rate of suicide. The cause for the increased
suicide risk is unknown so far.

3.2.1.Athletes:-

For athletes, high altitude produces two contradictory effects on
performance. For explosive events (sprints up to 400 metres, long
jump, triple jump) the reduction in atmospheric pressure signifies
less atmospheric resistance, which generally results in improved
athletic performance. For endurance events (races of 5,000 metres or
more) the predominant effect is the reduction in oxygen which
generally reduces the athlete's performance at high altitude. Sports
organisations acknowledge the effects of altitude on performance: the
International Association of Athletic Federations (IAAF), for example,
have ruled that performances achieved at an altitude greater than
1,000 metres (3,300 ft) will not be approved for record
purposes.Athletes also can take advantage of altitude acclimatization
to increase their performance. The same changes that help the body
cope with high altitude increase performance back at sea level. These
changes are the basis of altitude training which forms an integral
part of the training of athletes in a number of endurance sports
including track and field, distance running, triathlon, cycling and
swimming.


3.3Effect of altitude on animals:-

Decreased oxygen availability and decreased temperature make life at
high altitude challenging. Despite these environmental conditions,
many species have been successfully adapted at high altitudes. Animals
have developed physiological adaptations to enhance oxygen uptake and
delivery to tissues which can be used to sustain metabolism. The
strategies used by animals to adapt to high altitude depend on their
morphology and phylogeny.

3.3.1.Fish:-

Fish at high altitudes may also have a lower metabolic rate, as has
been shown in highland westslope cutthroat trout compared to
introduced lowland rainbow trout in the Oldman River basin. There is
also a general trend of smaller body sizes and lower species richness
at high altitudes observed in aquatic invertebrates, likely due to
lower oxygen partial pressures. These factors may decrease
productivity in high altitude habitats, meaning there will be less
energy available for consumption, growth, and activity, which provides
an advantage to fish with lower metabolic demands.The naked carp from
Lake Qinghai, like other members of the carp family, can use gill
remodelling to increase oxygen uptake in hypoxia. The response of
naked carp to cold and low-oxygen conditions seem to be at least
partly mediated by hypoxia-inducible factor 1 (HIF-1). It is unclear
whether this is a common characteristic in other high altitude
dwelling fish or if gill remodelling and HIF-1 use for cold adaptation
are limited to carp.

3.3.2.Rodents:-

Rodents living at high altitude include deer mice, guinea pigs and
rats. As small mammals they face the challenge of maintaining body
heat in cold temperatures, due to their large volume to surface area
ratio. As oxygen is used as a source of metabolic heat production, the
hypobaric hypoxia at high altitudes is problematic.There are a number
of mechanisms that help them survive these harsh conditions including
altered genetics of the hemoglobin gene in guinea pigs and deer
mice.Deer mice use a high percentage of fats as metabolic fuel at high
altitude to retain carbohydrates for small burst of energy. To convert
fats to energy in the form of ATP, more oxygen is required than to
convert the same amount of carbohydrates. The reason they use fats is
believed to be because they have it in large stores, but also means
that they must eat more or they will begin to lose weight.
Other physiological changes that occur in rodents at high altitude
include increased breathing rate and altered morphology of the lungs
and heart allowing more efficient gas exchange and delivery. Lungs of
high altitude mice are larger, with more capillaries, and hearts of
mice and rats at high altitude have a heavier right ventricle, which
pumps blood to the lungs.
At high altitudes, some rodents even shift their thermal neutral zone
so they may maintain normal basal metabolic rate at colder
temperatures.

3.3.3.Birds:-

Birds have been especially successful at living at high altitudes. In
general, birds have physiological features that are advantageous for
high-altitude flight. The respiratory system of birds moves oxygen
across the pulmonary surface during both inhalation and exhalation,
making it more efficient than that of mammals. In addition, the air
circulates in one direction through the parabronchioles in the lungs.
Parabronchioles are oriented perpendicular to the pulmonary arteries,
forming a cross-current gas exchanger. This arrangement allows for
more oxygen to be extracted compared to mammalian concurrent gas
exchange; as oxygen diffuses down its concentration gradient and the
air gradually becomes more deoxygenated, the pulmonary arteries are
still able to extract oxygen. Birds also have a high capacity for
oxygen delivery to the tissues because they have larger hearts and
cardiac stroke volume (mL / min) compared to mammals of similar body
size. Additionally, they have an increased vascularization in flight
muscle due to increased branching of capillaries and small muscle
fibres (which increases surface-area-to-volume ratio).These two
features facilitate oxygen diffusion from the blood to muscle,
allowing flight to be sustained during environmental hypoxia. Bird's
hearts and brains, which are very sensitive to arterial hypoxia, are
more vascularized compared to mammals. The bar-headed goose (Anser
indicus) is an iconic high flyer that surmounts the Himalayas during
migration,and serves as a model system for derived physiological
adaptations for high-altitude flight.



Keywords of high altitude:-

high altitude effects
high altitude fitness
high altitude balloon
high altitude cooking
high altitude sickness
high altitude baking adjustments
high altitude training
high altitude jump

Sub-orbital:-

A sub-orbital space flight is a spaceflight in which the spacecraft
reaches space, but its trajectory intersects the atmosphere or surface
of the gravitating body from which it was launched, so that it does
not complete one orbital revolution.

For example, the path of an object launched from Earth that reaches
100 km (62 mi) above sea level, and then falls back to Earth, is
considered a sub-orbital spaceflight. Some sub-orbital flights have
been undertaken to test spacecraft and launch vehicles later intended
for orbital spaceflight. Other vehicles are specifically designed only
for sub-orbital flight; examples include manned vehicles such as the
X-15 and SpaceShipOne, and unmanned ones such as ICBMs and sounding
rockets.
Sub-orbital spaceflights are distinct from flights that attain orbit
but use retro-rockets to deorbit after less than one full orbital
period. Thus the flights of the Fractional Orbital Bombardment System
would not be considered sub-orbital; instead these are simply
considered flights to low Earth orbit.Usually a rocket is used, but
experimentally a sub-orbital spaceflight has also been achieved with a
space gun.

Contents:-

1. Altitude requirement
2. Orbit
3. Speed, range, altitude
4. Flight duration

1.Altitude requirement:-

By one definition a sub-orbital spaceflight reaches an altitude higher
than 100 km above sea level. This altitude, known as the Kármán line,
was chosen by the Fédération Aéronautique Internationale because it is
roughly the point where a vehicle flying fast enough to support itself
with aerodynamic lift from the Earth's atmosphere would be flying
faster than orbital speed. The US military and NASA award astronaut
wings to those flying above 50 miles (80.47 km), although the US State
Department appears to not support a distinct boundary between
atmospheric flight and space flight.

2.Orbit:-

During freefall the trajectory is part of an elliptic orbit as given
by the orbit equation. The perigee distance is less than the radius of
the Earth R including atmosphere, hence the ellipse intersects the
Earth, and hence the spacecraft will fail to complete an orbit.

3.Speed, range, altitude:-

To minimize the required delta-v (an astrodynamical measure which
strongly determines the required fuel), the high-altitude part of the
flight is made with the rockets off (this is technically called
free-fall even for the upward part of the trajectory). The maximum
speed in a flight is attained at the lowest altitude of this free-fall
trajectory, both at the start and at the end of it.
If one's goal is simply to "reach space", for example in competing for
the Ansari X Prize, horizontal motion is not needed. In this case the
lowest required delta-v is about 1.4 km/s, for a sub-orbital flight
with a maximum speed of about 1 km/s. Moving slower, with less
free-fall, would require more delta-v.
Compare this with orbital spaceflights: a low Earth orbit (LEO), with
an altitude of about 300 km), needs a speed around 7.7 km/s, requiring
a delta-v of about 9.2 km/s.
For sub-orbital spaceflights covering a horizontal distance the
maximum speed and required delta-v are in between those of a vertical
flight and a LEO. The maximum speed at the lower ends of the
trajectory are now composed of a horizontal and a vertical component.
The higher the horizontal distance covered, the more are both speeds,
and the more is the maximum altitude. For the V-2 rocket, just
reaching space but with a range of about 330 km, the maximum speed was
1.6 km/s. Scaled Composites SpaceShipTwo which is under development
will have a similar free-fall orbit but the announced maximum speed is
1.1 km/s (perhaps because of engine shut-off at a higher altitude).
For larger ranges, due to the elliptic orbit the maximum altitude can
even be considerably more than for a LEO. On an intercontinental
flight, such as that of an intercontinental ballistic missile or
possible future commercial spaceflight, the maximum speed is about 7
km/s, and the maximum altitude about 1200 km. Note that an
intercontinental flight at an altitude of 300 km would require a
larger delta-v than that of a LEO. It should be noted that any
spaceflight that returns to the surface, including sub-orbital ones,
will undergo atmospheric reentry. The speed at the start of that is
basically the maximum speed of the flight. The aerodynamic heating
caused will vary accordingly: it is much less for a flight with a
maximum speed of only 1 km/s than for one with a maximum speed of 7 or
8 km/s.


4.Flight duration:-

In a vertical flight of not too high altitudes, the time of the
free-fall is both for the upward and for the downward part the maximum
speed divided by the acceleration of gravity, so with a maximum speed
of 1 km/s together 3 minutes and 20 seconds. The duration of the
flight phases before and after the free-fall can vary.
For an intercontinental flight the boost phase takes 3 to 5 minutes,
the free-fall (midcourse phase) about 25 minutes. For an ICBM the
atmospheric reentry phase takes about 2 minutes; this will be longer
for any soft landing, such as for a possible future commercial
flight.Suborbital flights can last many hours. Pioneer 1 was NASA's
first space probe, intended to reach the Moon. A partial failure
caused it to instead follow a suborbital trajectory, reentering the
Earth's atmosphere 43 hours after launch.








































1 comment:

  1. Thanks for sharing the nice information about Gulfstream's Aircraft, the G280 with a beautiful images. Really a great blog!!

    Aircraft For sale

    ReplyDelete