• Weightless
https://store.theartofservice.com/the-weightless-toolkit.html
Effect of spaceflight on the human body - The effects of weightlessness
1
Following the advent of space stations that
can be inhabited for long periods of time,
exposure to weightlessness has been
demonstrated to have some deleterious
effects on human health. Humans are welladapted to the physical conditions at the
surface of the earth, and so in response to
weightlessness, various Biological
system|physiological systems begin to
change, and in some cases, atrophy. Though
these changes are usually temporary, some
do have a long-term impact on human health.
https://store.theartofservice.com/the-weightless-toolkit.html
Effect of spaceflight on the human body - The effects of weightlessness
1
Short-term exposure to microgravity
causes space adaptation syndrome, a
self-limiting nausea caused by
derangement of the vestibular system
https://store.theartofservice.com/the-weightless-toolkit.html
Spaceflight - Weightlessness
In a microgravity environment such as
that provided by a spacecraft in orbit
around the Earth, humans experience a
sense of weightlessness. Short-term
exposure to microgravity causes space
adaptation syndrome, a self-limiting
nausea caused by derangement of the
vestibular system. Long-term exposure
causes multiple health issues. The most
significant is bone loss, some of which is
permanent, but microgravity also leads to
significant deconditioning of muscular
and cardiovascular tissues.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Marconi Union - Weightless
On 16 October 2011, Marconi Union
created an eight minute track, titled
Weightless, in collaboration with the British
Academy of Sound Therapy.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Marconi Union - Weightless
1
According to scientists at the Mindlab
institution (a commercial
'neuromarketing' company) it induced a
65% reduction in overall anxiety and
brought test subjects' resting pulse rates
to 35% of their usual resting rates. The
song features guitar, piano and
manipulated field recordings. It is
punctuated throughout by low tones that
supposedly induce a trance-like state.
This piece propelled the band into the
media spotlight and news reports, and
was reported in newspapers worldwide.
https://store.theartofservice.com/the-weightless-toolkit.html
Marconi Union - Weightless
1
In November 2011, Marconi Union
were featured in Time
magazine|Time magazine's list of
Inventors of the Year, for writing and
recording Weightless.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications)
1
'Weightless' is a proposed Proprietary
protocol|proprietary open standard|open
wireless technology standard for
exchanging data between a base station
and thousands of machines around it
using White spaces (radio)|White space
(frequency channels intended for TV
broadcasting but currently unoccupied)
with high levels of security.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications)
Weightless is managed by the Weightless
SIG, or Special Interest Group, which was
revealed to the public on 7 December 2012.
An inaugural event for industry was held at
the Moller Centre in Cambridge, UK by
Cambridge Wireless on Friday, 30 September
2011. Representatives – mainly engineers –
from many companies from around the world
attended. Presentations were given by Neul,
Landis+Gyr, Cable Wireless
Worldwide|Cable Wireless, and ARM
Holdings|ARM.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications)
1
The intention is that devices must be
qualified by the Weightless Special
Interest Group to standards defined by
the SIG. Patents would only be licensed
to those qualifying devices; thus the
protocol, whilst open, may be regarded
as proprietary.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Name and logo
1
The name Weightless was chosen to
reflect the allegedly light-weight nature
of the protocol, meaning that the
overhead per transmission is
minimised for devices that need to
communicate just a few bytes of data.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Name and logo
1
The Weightless logo is trademarked and
appears as uppercase letters with the 'W'
appearing in the top-right corner of a light
blue box that has a solid blue line above it.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Name and logo
1
One of the presenters at the inaugural SIG
event in September 2011 stated jokingly, in
reference to cellular communication
standards, Weightless is not 1G, 2G, 3G
or even 4G – it is ZERO G.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Implementation
Weightless uses Time-division duplex
operation with frequency hopping and
variable spreading factors in an attempt
to increase range and accommodate low
power devices in frequency bands, or
channels, within the terrestrial
television broadcast band. Channels that
are in use by a nearby television
transmitter are identified and left
unaffected while channels not being
used for broadcasting television can be
allocated for use by Weightless devices.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Implementation
A network of base stations
communicate with the Internet, or a
private network, in order to pass
information from devices to a
computer system; and to pass
information back to the devices. The
downlink to devices uses time slots
(TDMA) and the uplink to the base
station is divided into sub-channels so
that several devices can communicate
to the base station.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Communication and connection
1
A base station transmits a Weightless
frame which is received by a few
thousand devices. The devices are
allocated a specific time and
frequency to transmit their data back
to the base station. The base station is
connected to the Internet or a private
network. The base station accesses a
database to identify the frequencies,
or channels, that it can use without
interfering with terrestrial television
broadcasts in its local area.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Uses
1
Weightless is a wireless communications
protocol designed to connect Smart
Machines to the Internet – so-called
Machine to machine|Machine-to-Machine
(M2M) communications – over distances
ranging from a few metres to about 10km.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - List of applications
* Smart cars – vehicle
diagnostics and upgrades
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - List of applications
1
* Industrial machine
monitoring
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Weightless (wireless communications) - Weightless vs. Wi-Fi (IEEE 802.11af)
Other technologies which use the white
space – the channels not used for
terrestrial television broadcast in a
particular area – are also being developed.
One is Wi-Fi under the developing
standard IEEE 802.11af.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Weightless vs. Cognitive Radio (IEEE 802.22)
1
The IEEE 802.22 standard defines a MAC
and PHY layer for TV WhiteSpaces that
complies with the FCC and international
standards for broadcasting in this
spectrum. It also defines general protocol
model for negotiating and selecting shared
spectrum band for device operation. A
Weightless Radio implementation would
comply with this standard to cooperatively
share the available TV WhiteSpace
spectrum.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Devices
1
Currently the majority of the devices
that are envisionsed to use the
Weightless standard are mainly of
industrial and medical type, such as
smart electric meters, health
monitors, vehicle tracking, etc.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Specifications and features
The Weightless specification was
developed as a proprietary machine-tomachine, allegedly low-cost, low-power
communication system for use in the
White spaces (radio)|white space between
TV channels in 2011 by engineers working
at Neul in Cambridge, UK.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Specifications and features
1
The specification is based on Timedivision duplex technology with
Spread spectrum frequency hopping
in an attempt to minimise the impact
of interference and with variable
spreading factors in an attempt to
increase range (at the expense of
lower data rate) and to accommodate
low power devices with low data rates.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Weightless v1.0
A formal standard was published in
2013, however it was not made freely
available to general public -- it was only
available to the members of Weightless
SIG who paid membership fees. A brief
and incomplete overview of the
standard may be available without a
charge to the so-called observer
members of SIG.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Setting up connections
1
A base station queries a database which
identifies the channels that are being used
for terrestrial television broadcast in its
local area. The channels not in use – the
so-called White spaces (radio)|white
space – can be used by the base station
to communicate with terminals using the
Weightless protocol.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Setting up connections
1
Terminals will be allegedly designed
to be low cost fit and forget devices –
meaning that they are expected to use
minimal power so that they could
work autonomously for long periods
close to the typical shelf-life of a
battery (probably several years).
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Security Concerns
It is proposed that the entire data
transmission is encoded. It is claimed that
that the protocol was designed to be
secure and guarantee message delivery.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Air interface
1
A database is queried by a base station to
determine which channels are in use by
terrestrial television broadcast stations in
the area, and which ones are free for use
by white space devices (such as those
utilising Weightless)
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (wireless communications) - Security
1
The communications link between the base station
and the devices is encrypted.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Wet Wet Wet song)
1
'Weightless' is a pop music|pop
song by Scottish group Wet Wet
Wet
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Wet Wet Wet song) - Track listings
1
# Exclusive video
footage
https://store.theartofservice.com/the-weightless-toolkit.html
Secondhand Serenade - Hear Me Now and Weightless EP (2010–2011)
1
Secondhand Serenade's third studio album is entitled
Hear Me Now (Secondhand Serenade album)|Hear
Me Now, and was released on August 3, 2010.Thanks
to Chris Lipa And His local band from Michigan for the
additions to the album, The album's track listing has
also been
announced.[http://puregrainaudio.com/news/secondha
nd-serenade-returns-with-hear-me-now-due-outaugust-3rd Upcoming album details] from
PureGrainAudio.com In a recent interview, Vesely
stated that the new record will be more upbeat than
his last album, which focused on
relationships.http://www.billboard.com/articles/columns
/daily-noise/959710/secondhand-serenade-kellyclarkson-talk-new-material
https://store.theartofservice.com/the-weightless-toolkit.html
Secondhand Serenade - Hear Me Now and Weightless EP (2010–2011)
1
On June 1, Something More was released
onto iTunes as a deluxe single with a
bonus track You Are a Drug, a video
showing the making of Something More,
and a digital booklet to the new single.
https://store.theartofservice.com/the-weightless-toolkit.html
Secondhand Serenade - Hear Me Now and Weightless EP (2010–2011)
1
The vocals of Juliet Simms from American
rock band Automatic Loveletter were
featured on the song Hear Me Now and
the cover of Fix You, originally performed
by British rock band Coldplay.
https://store.theartofservice.com/the-weightless-toolkit.html
Secondhand Serenade - Hear Me Now and Weightless EP (2010–2011)
1
On July 21, while on tour in Dallas,
Vesely announced that a
downloadable track pack for Rock
Band would be made available soon,
featuring multiple Secondhand
Serenade hits including Fall for You.
https://store.theartofservice.com/the-weightless-toolkit.html
Secondhand Serenade - Hear Me Now and Weightless EP (2010–2011)
On July 27, Vesely added the eleven
tracks off of the new album to his
MySpace and made them available for
streaming for fans. Many of these
songs have also leaked onto sites such
as YouTube. On November 23, 2010,
Vesely released a free online
download for a demo of a new song of
the new Extended play|EP entitled Let
Me In. The next single of the new
album is a new version of You I
featuring Cady Groves.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Secondhand Serenade - Hear Me Now and Weightless EP (2010–2011)
1
In March 2011, Vesely announced he
was mastering the new EP and that it
would be entitled Weightless
EP|Weightless. Weightless was
released digitally on May 3, 2011 and
consists of five songs: Our Time, Let
Me In, Animal (Neon Trees Cover), You
I (Acoustic), and Never Too Late.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (All Time Low song)
1
'Weightless' is a song by American
pop punk band All Time Low and the
first and lead single from their third
studio album Nothing Personal
(album)|Nothing Personal (2009)
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (All Time Low song) - Meaning
1
Lead vocalist Alex Gaskarth stated in an
interview with MTVu that The whole
mentality of the song is like, you feel like
you're stuck in this like, negative space
and you just want to get out. Summer's
rolling up and uh, everybody's finishing up
with school and everybody's getting like
the exam beatdown.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (All Time Low song) - Meaning
1
In the Nothing Personal album trailer,
Jack Barakat said that the song is
about not wanting to grow up and just
wanting to be a kid.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (All Time Low song) - Music video
The music video for Weightless
commenced filming on May 20, directed
by Matthew Stawski. Fans were invited
to go on the set and be a part of the
music video. It debuted on MTV, MTV2,
mtvU and HITS the day before the
album's release, on July 6, 2009. The
video features cameo appearances by
Pete Wentz from Fall Out Boy and Mark
Hoppus from Blink-182 with a joke that
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (All Time Low song) - Music video
1
(on mobile Twitter) that All Time Low rips
off Fall Out Boy, but Mark Hoppus thinks to
himself that both All Time Low and Fall Out
Boy rip off Blink-182. The camera follows
the action through the venue, with text that
is insulting everyone, stating Loser!. The
video ends with the slogan Nothing
Personal, which is not only a reference to
the album, but is also the theme of the
video.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless
*Weightless (wireless communications),
proposed proprietary open wireless technology
standard
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless - Music
*Weightless (Animals as Leaders
album)|Weightless (Animals as Leaders
album), second album by instrumental
progressive metal group Animals as
Leaders
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless - Music
*Weightless (The Skinny Boys
album)|Weightless (The Skinny Boys
album), debut album by rap group The
Skinny Boys
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless - Music
*Weightless (All Time Low
song)|Weightless (All Time Low
song), song by American pop punk
band All Time Low
1
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Weightless - Music
1
*Marconi Union|Weightless (Marconi Union
song), the ...most relaxing song ever.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless - Music
1
*Weightless, song by alternative rock band
Black Lab from their album Passion Leaves a
Trace
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Animals as Leaders album)
'Weightless' is the second album by
instrumental progressive metal group
Animals as Leaders. It was released on
November 4, 2011 in Europe, November
7, 2011 in the UK, and November 8,
2011 in the US by Prosthetic Records.
The album charted at #92 on Billboard
200|Billboard’s Top 200 Chart, as well
as #7 on Billboard
(magazine)|Billboard’s Top Hard Music
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Animals as Leaders album)
Unlike the Animals as Leaders
(album)|previous Animals as Leaders
album, Weightless features a trio line-up
instead of just consisting of Tosin Abasi
along with featuring real drums in addition
to programmed drums. Both guitarists in
the group (Abasi and Javier Reyes) play 8stringed guitars on this release.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Animals as Leaders album) - Personnel
1
* Tosin Abasi – eight-string guitar
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Animals as Leaders album) - Personnel
1
* Navene Koperweis –
drums
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Animals as Leaders album) - Personnel
1
* Navene Koperweis - audio
engineering|engineering
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Animals as Leaders album) - Personnel
1
* Javier Reyes Audio mixing
(recorded
music)|mixing
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (Animals as Leaders album) - Personnel
1
* Dustin Miller - Audio
mastering|mastering
https://store.theartofservice.com/the-weightless-toolkit.html
Weightless (The Skinny Boys album)
'Weightless' is the debut album by rap
group The Skinny Boys. It was released in
1986 for Warlock Records and was
produced by Mark Bush and Chuck
Chillout.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness
1
Counterintuitively, a uniform gravitational
field does not by itself cause stress or
strain, and a body in free fall in such an
environment experiences no g-force
acceleration and feels weightless
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness
When bodies are acted upon by nongravitational forces, as in a centrifuge, a
rotating space station, or within a space
ship with rockets firing, a sensation of
weight is produced, as the contact forces
from the moving structure act to
overcome the body's inertia. In such
cases, a sensation of weight, in the sense
of a state of stress can occur, even if the
gravitational field was zero. In such
cases, g-forces are felt, and bodies are
not weightless.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness
When the gravitational field is nonuniform, a body in free fall suffers tidal
effects and is not stress-free. Near a
black hole, such tidal effects can be very
strong. In the case of the Earth, the
effects are minor, especially on objects
of relatively small dimension (such as
the human body or a spacecraft) and the
overall sensation of weightlessness in
these cases is preserved. This condition
is known as microgravity and it prevails
in orbiting spacecraft.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - Weightlessness in Newtonian mechanics
Weightlessness in this sense can be
achieved by removing the body far away
from the source of gravity
1
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Weightlessness - Weightlessness in Newtonian mechanics
1
This is the weightlessness in free
fall in a uniform gravitational field
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Weightlessness - Weightlessness in Newtonian mechanics
To sum up, we have two notions of
weight of which weight1 is dominant.
Yet 'weightlessness' is typically
exemplified not by absence of weight1
but by the absence of stress associated
with weight2. This is the intended
sense of weightlessness in what
follows below.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - Weightlessness in Newtonian mechanics
1
A body is stress free, exerts zero weight2,
when the only force acting on it is weight1
as when in free fall in a uniform
gravitational field. Without subscripts, one
ends up with the odd-sounding conclusion
that 'a body is weightless when the only
force acting on it is its weight.'
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Weightlessness - Weightlessness in Newtonian mechanics
1
The apocryphal apple that fell on Newton's head
can be used to illustrate the issues involved
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Weightlessness - Stress during free fall
:1. In a uniform gravitational field:
Consider any cross-section dividing the
body into two parts. Both parts have the
same acceleration and the force exerted
on each is supplied by the external source
of the field. There is no force exerted by
one part on the other. Stress at the crosssection is zero. Weight2 is zero.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - Stress during free fall
:2. In a non-uniform gravitational field:
Under gravity alone, one part of the body
may have a different acceleration from
another part. This would tend to deform
the body and generate internal stresses if
the body resists deformation. Weight2 is
not 0.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - Stress during free fall
1
Throughout this discussion on using stress
as an indicator of weight, any pre-stress
which may exist within a body caused by a
force exerted on one part by another is not
relevant. The only relevant stresses are
those generated by external forces applied
to the body.
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - Stress during free fall
1
An object in a straight free fall, or in a
more complex inertial trajectory of free
fall (such as within a reduced gravity
aircraft or inside a space station), all
experience weightlessness, since they
do not experience the mechanical
forces that cause the sensation of
weight.
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Weightlessness - Force fields other than gravity
1
Such a body would
then be stress free
and be classed as
weightless
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Weightlessness - Weightlessness and proper acceleration
On this approach,
weightlessness holds when
proper acceleration is zero.
1
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Weightlessness - How to avoid weightlessness
1
Weightlessness is in contrast with current
human experiences in which a nonuniform force is acting, such as:
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - How to avoid weightlessness
*standing on the ground, sitting in a
chair on the ground, etc., where gravity
is countered by the support force of the
ground,
1
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Weightlessness - How to avoid weightlessness
1
*flying in a plane, where a support force is
transmitted from the Lift (force)|lift the
wings provide (special
trajectory|trajectories which form an
exception are described below),
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Weightlessness - How to avoid weightlessness
1
*during atmospheric reentry, or during
the use of a parachute, when
atmospheric drag decelerates a vehicle,
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Weightlessness - How to avoid weightlessness
*during an orbital maneuver in a
spacecraft, or during the launch phase,
when rocket engines provide thrust.
1
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Weightlessness - How to avoid weightlessness
In cases where an object is not
weightless, as in the above examples,
a force acts non-uniformly on the
object in question
1
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Weightlessness - Tidal forces
Tidal forces arise when the
gravitational field is not uniform and
gravitation gradients exist. Such
indeed is the norm and strictly
speaking any object of finite size even
in free-fall is subject to tidal effects.
These are impossible to remove by
inertial motion, except at one single
nominated point of the body.
1
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Weightlessness - Tidal forces
The Earth is in free fall but the
presence of tides indicates that it is in a
non-uniform gravitational field
1
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Weightlessness - Tidal forces
When the size of a region being
considered is small relative to its
distance from the gravitating mass the
assumption of uniform gravitational
field holds to a good approximation. Thus
a person is small relative to the radius of
Earth and the field for a person at the
surface of the earth is approximately
uniform. The field is strictly not uniform
and is responsible for the phenomenon
of microgravity. Objects near a black
hole are subject to a highly non-uniform
gravitational field.
1
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Weightlessness - Frames of reference
1
Weightlessness can thus be realised
for short periods of time in an
airplane following a specific elliptic
flight path, often mistakenly called a
parabolic flight
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - Zero-g, zero gravity, accelerometers
Microgravity (or µg) is used to refer to
situations that are substantially weightless
but where g-force stresses within objects
due to tidal effects, as discussed above,
are around a millionth of that at the Earth's
surface.
1
https://store.theartofservice.com/the-weightless-toolkit.html
Weightlessness - Zero-g, zero gravity, accelerometers
1
An accelerometer using a single weight or
vibrating element and not measuring
gradients across distances inside the
accelerometer (which could be used to
detect microgravity or tidal forces), cannot
tell the difference between free fall in a
gravity field, and weightlessness due to
being far from masses and sources of
gravitation
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Weightlessness - Sensation of weight
Because of the distribution of mass
throughout a person's body, the magnitude
of the reaction force varies between a
person's feet and head
1
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Weightlessness - A common misconception
A common conception about
spacecraft orbiting the earth is that
they are operating in a gravity free
environment. Although there is a way of
making sense of this within the physics
of Einstein's general relativity, within
Newtonian physics, this is technically
inaccurate .
1
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Weightlessness - A common misconception
1
In Newtonian physics, the sensation of
weightlessness experienced by
astronauts is not the result of there
being zero gravitational acceleration
(as seen from the Earth), but of there
being no g-force that an astronaut can
feel because of the free-fall condition,
and also there being zero difference
between the acceleration of the
spacecraft and the acceleration of the
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Weightlessness - A common misconception
A geostationary satellite is of special
interest in this context. Unlike other
objects in the sky which rise and set, an
object in a geostationary orbit appears
motionless in the sky, apparently defying
gravity. In fact, it is in a circular equatorial
orbit with a period of one day.
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Weightlessness - Relativity
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To a modern physicist working with
Einstein's general theory of relativity,
the situation is even more
complicated than is suggested above
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Weightlessness - Relativity
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In the theory of general relativity, the only
gravity which remains for the observer
following a falling path or inertial path near
a gravitating body, is that which is due to
non-uniformities which remain in the
gravitational field, even for the falling
observer
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Weightlessness - Microgravity
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The term 'micro-g environment' (also 'µg',
often referred to by the term 'microgravity')
is more or less a synonym of
weightlessness and zero-G, but indicates
that g-forces are not quite zero, just very
small.
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Weightlessness - Reduced weight in aircraft
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Airplanes have been used since 1959 to
provide a nearly weightless
environment in which to train
astronauts, conduct research, and film
motion pictures. Such aircraft are
commonly referred by the nickname
Vomit Comet.
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Weightlessness - Reduced weight in aircraft
During this period, the plane's
occupants experience about 25
seconds of weightlessness, before
experiencing about 25 seconds of 2 g
acceleration (twice their normal
weight) during the pull-out from the
parabola
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Weightlessness - NASA's Reduced Gravity Aircraft
Versions of such airplanes have been
operated by NASA's Reduced Gravity
Research Program since 1973, where the
unofficial nickname originated.[http://jscaircraftops.jsc.nasa.gov/Reduced_Gravity/index.h
tml Reduced Gravity Research Program]
NASA later adopted the official nickname
'Weightless Wonder' for
publication.[http://www.nasaexplores.com/
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Weightlessness - NASA's Reduced Gravity Aircraft
NASA's Microgravity University Reduced Gravity Flight Opportunities
Plan, also known as the Reduced
Gravity Student Flight Opportunities
Program, allows teams of
undergraduates to submit a
microgravity experiment proposal. If
selected, the teams design and
implement their experiment, and
students are invited to fly on NASA's
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Weightlessness - European Space Agency A300 Zero-G
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ESA flies campaigns of three flights on
consecutive days, each flying about 30
parabolas, for a total of about 10
minutes of weightlessness per flight
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Weightlessness - European Space Agency A300 Zero-G
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Other aircraft it has used include the
Russian Ilyushin Il-76 MDK and French
Sud Aviation Caravelle|Caravelle.
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Weightlessness - Others
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The Zero Gravity Corporation, founded in
1993 by Peter Diamandis, Byron
Lichtenberg, and Ray Cronise, operates a
modified Boeing 727 which flies parabolic
arcs to create 25–30 seconds of
weightlessness. Flights may be purchased
for both tourism and research purposes.
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Weightlessness - Ground-based drop facilities
Ground-based facilities that produce
weightless conditions for research
purposes are typically referred to as drop
tubes or drop towers.
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Weightlessness - Ground-based drop facilities
NASA's Zero Gravity Research
Facility, located at the Glenn Research
Center in Cleveland, Ohio, is a 145meter vertical shaft, largely below the
ground, with an integral vacuum drop
chamber, in which an experiment
vehicle can have a free fall for a
duration of 5.18 seconds, falling a
distance of 132 meters. The
experiment vehicle is stopped in
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Weightlessness - Ground-based drop facilities
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Also at NASA Glenn is the 2.2 Second
Drop Tower, which has a drop distance
of 24.1 meters. Experiments are
dropped in a drag shield, in order to
reduce the effects of air drag. The
entire package is stopped in a 3.3 meter
tall air bag, at a peak deceleration rate
of approximately . While the Zero
Gravity Facility conducts one or two
drops per day, the 2.2 Second Drop
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Weightlessness - Ground-based drop facilities
NASA's Marshall Space Flight Center
hosts another drop tube facility that is 105
meters tall and provides a 4.6 second free
fall under near-vacuum
conditions.[http://science.nasa.gov/ssl/msa
d/dtf/tube.htm Marshall Space Flight
Center Drop Tube Facility]
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Weightlessness - Ground-based drop facilities
Humans cannot utilize these gravity
shafts, as the deceleration experienced by
the drop chamber would likely kill or
seriously injure anyone using them; is
about the highest deceleration that a fit
and healthy human can withstand
momentarily without sustaining injury.
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Weightlessness - Ground-based drop facilities
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Other drop facilities worldwide
include:
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Weightlessness - Ground-based drop facilities
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* Experimental drop tube of the metallurgy
department of Grenoble – 3.1 s free fall
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Weightlessness - Ground-based drop facilities
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* Fallturm Bremen University of Bremen in
Bremen (city)|Bremen – 4.74 s free fall
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Weightlessness - Ground-based drop facilities
* Queensland
University of
Technology Drop
Tower - 2.0 s free fall
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Weightlessness - Neutral buoyancy
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Weightlessness can also be simulated
by creating the condition of neutral
buoyancy, in which human subjects
and equipment are placed in a water
environment and weighted or buoyed
until they hover in place
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Weightlessness - Neutral buoyancy
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Neutral buoyancy is not identical to
weightlessness
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Weightlessness - Weightlessness in a spacecraft
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Weightlessness does not occur when a
spacecraft is firing its engines or when reentering the atmosphere, even if the
resultant acceleration is constant
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Weightlessness - Weightlessness in a spacecraft
Weightlessness in an orbiting
spacecraft is physically identical to
free-fall, with the difference that
gravitational acceleration causes a net
change in the direction, rather than the
magnitude, of the spacecraft's velocity.
This is because the acceleration Vector
(geometric)|vector is perpendicular to
the velocity vector.
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Weightlessness - Weightlessness in a spacecraft
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In typical free-fall, the acceleration of
gravity acts along the direction of an
object's velocity, linearly increasing its
speed as it falls toward the Earth, or
slowing it down if it is moving away
from the Earth
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Weightlessness - Weightlessness at the center of a planet
The net gravitational force due to a
spherically symmetrical planet is zero
at the center. This is clear because of
symmetry, and also from Newton's
shell theorem which states that the net
gravitational force due to a spherically
symmetric shell, e.g., a hollow ball, is
zero anywhere inside the hollow space.
Thus the material at the center is
weightless.
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Weightlessness - Human health effects
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Following the advent of space stations
that can be inhabited for long periods,
exposure to weightlessness has been
demonstrated to have some deleterious
effects on human health. Humans are
well-adapted to the physical conditions
at the surface of the Earth. In response
to an extended period of
weightlessness, various physiological
systems begin to change and atrophy.
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Weightlessness - Human health effects
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The most common problem experienced
by humans in the initial hours of
weightlessness is known as space
adaptation syndrome or SAS, commonly
referred to as space sickness
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Weightlessness - Human health effects
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Astronauts subject to long periods of
weightlessness wear pants with elastic
bands attached between waistband and
cuffs to compress the leg bones and
reduce
osteopenia.[http://www.spacefuture.co
m/habitat/healthfitness.shtml Health
Fitness], Space Future Other
significant effects include fluid
redistribution (causing the moon-face
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Weightlessness - Human health effects
In addition, after long space flight
missions, astronauts may experience
severe visual system|eyesight
problems.[http://www.cnn.com/video/#/vide
o/us/2012/02/09/pkg-zarrella-astronautvision.cnnCNN News (CNN-TV,
02/09/2012) - Video (02:14) - Male
Astronauts Return With Eye Problems]
Such eyesight problems may be a major
concern for future deep space flight
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Weightlessness - Human health effects
On December 31, 2012, a NASAsupported study reported that manned
spaceflight may harm the brains of
astronauts and accelerate the onset of
Alzheimer's disease.
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Weightlessness - Effects on non-human organisms
Russian scientists have observed
differences between cockroaches
conceived in space and their
terrestrial counterparts. The spaceconceived cockroaches grew more
quickly, and also grew up to be faster
and tougher.
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Weightlessness - Effects on non-human organisms
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Chicken eggs that are put in microgravity
two days after fertilization appear not to
develop properly, whereas eggs put in
microgravity more than a week after
fertilization develop normally.
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Weightlessness - Effects on non-human organisms
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A 2006 Space Shuttle experiment found
that Salmonella typhimurium, a bacterium
that can cause food poisoning, became
more virulent when cultivated in space.
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Weightlessness - Technical adaptation in zero-gravity
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Weightlessness can cause serious
problems on technical instruments,
especially those consisting of many
mobile parts
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