LITERATURA AUXILIAR


INSTITUTO DE AERONÁUTICA E ESPAÇO
CAMPUS DE PESQUISAS GEOFÍSICAS MAJOR EDSEL DE FREITAS COUTINHO (
FACULDADES INTEGRADAS ESPÍRITA
LABORATÓRIO DE CONSTRUÇÃO DE EQUIPAMENTOS CIENTÍFICOS

AUTOR: LEITHOLD, ÂNGELO ANTÔNIO; CONVÊNIO IAE-UNIBEM (C)2007

BIBLIOTECA  > Astronomia - UNIBEM > Grupo de Física da UNIBEM > UNIBEM

A Anomalia Magnética do Atlântico Sul, AMAS ou SAA (do inglês, South Atlantic Anomaly) é uma região onde a parte mais interna do cinturão de Van Allen tem a máxima aproximação com a superfície da Terra. O resultado é que para uma dada altitude, a intensidade de radiação é mais alta nesta região do que em qualquer outra, observar que na figura 1 existem diferentes tonalidades de azul, estas indicam uma menor ''blindagem'' propiciada pelo campo magnético da Terra. Os Links embaixo relacionam alguns efeitos que podem ocorrer na região da AMAS.

ESTUDO DA PROPAGAÇÃO DE RÁDIO E DAS DESCARGAS ATMOSFÉRICAS NA REGIÃO DA ANOMALIA MAGNÉTICA DO ATLÂNTICO SUL

001A_Estudos sobre a Atmosfera .pdf 1M

002_Ondas de Alfven_a.ppt 181 k

003_Ondas de Alfven.pdf 246 k

004_AMAS biominerais pdf 369 k

005_Orige interna da AMAS_e a visão espacial .pdf 478 k

006_Análise da atmosfera na região da AMAS_.pdf 319 k

007_Descrição da Anomalia Magnética do Atlântico Sul AMAS .pdf 511 k

008_Astrofisica_e os jatos de partículas_py5aal.pdf 1M

009_Clima_e suas variação.pdf 4 M

010_Eletricidade_Atmosférica .pdf 210 k

011_Espalhamento_Atmosfera_Superior_.pdf 246k

012_Estratégia_Espacial_py5aal.pdf  45 k

013_Números e índices solares .pdf 233 k

014_Plasma_Ionosférico na região da Anomalia Magnética do Atlântico Sul_.pdf 2M

015_Pulsações Geomagnéticas na região da Anomalia Magnética do Atlântico Sul_.pdf 1M

016_Quasar_Fornalha_Universo.pdf 437k

017_Relações entre o clima e a saúde humana.pdf 46 k

018_Anéis de crescimento das árvores e sua relação com a radiação solar .pdf 4M

019_Velocidade_de rotação da Terra .pdf 1M


OUTROS TEXTOS



BIBLIOGRAFIA UTILIZADA


HARTMANN AMAS CAUSAS EFEITOS  PY5AAL.pdf - 9981 KB Visualizar

 MATSUOKA Impacto das Explosões Solares no Comportamento da Ionosfera e no 
Posicionamento com GPS na Região Brasileira.PDF- 581 KB Visualizar

Russel THE MAGNETOSPHERE  PY5AAL.pdf - 272 KB Visualizar 
The magnetic Field of the earth to a large extent shields it from the continual
supersonic outflow of the sun's ionized upper atmosphere. However, some of the
mass, momentum and energy of this solar wind gains entry into the
magnetosphere, powering current systems, geomagnetic storms and auroral
displays. Other planets too have magnetospheres. Some of these magnetospheres
are due to intrinsic magnetic fields as in the case of the earth. Others are due solely
to the interaction of the planet with the solar wind as in the case of a comet.

Demorest Dynamo Theory and Earth Magnetic Field py5aal.pdf - 266 KB Visualizar
The Earth's magnetic .eld is basically a dipole, which is aligned o. the
rotation axis by about 11 degrees. Historically, this was believed to be
caused by some kind of permanent magnetization of material in the earth,
and dynamo theory was orginally put forward to explain the sun's magnetic
.eld. However, there are several pieces of evidence which point away from
such a theory.

Boris Chertok Rockets and People vol 1  py5aal.pdf - 3399 KB Visualizar


Chertok, Boris  Rockets and People py5aal vol2.pdf - 3651 KB Visualizar 
However, two years later the American physicist James Van Allen proved that
what the third satellite’s instruments had actually measured was not from secondary
emission, but rather from primary particles of the Earth’s previously unknown
radiation belts.12 That is why the Americans named these radiation belts the “Van
Allen Belts.” In Vernov’s defense it must be said that he erred due to the failure of
the satellite’s telemetry recording device. Vernov was not able to receive measurements
of the radiation activity over the satellite’s entire orbital pass, but he received
measurements only in direct reception mode when the satellite was flying over the
territory of the USSR. Van Allen made his discovery using the results measured by
 the Earth’s magnetic field holds in charged particles (protons, electrons, and
α-particles) that possess a great deal of kinetic energy. These particles remain in
near-Earth space, held in what is referred to as the magnetic trap.
This discovery was a great scientific sensation and had important practical significance
for cosmonautics. Spacecraft, whose orbits passed through radiation belts,
were exposed to significant levels of radiation that damaged, in particular, the structure
of their solar array sensors. For crewed spacecraft, a prolonged stay in these belts
is not acceptable at all and can be very dangerous.
After the publication of Van Allen’s discoveries, we decided, albeit belatedly, to
correct the mistake committed through the failure of the recording device on the
third satellite. In our literature, however, they started to refer to the radiation belts
as the “Van Allen-Vernov belts.”

Chertok, Boris Rockets and People py5aal v3.pdf - 7399 KB Visualizar
We still had enough propellant for all sorts of experiments on Baykal,
but Kerimov and Mishin, inspired by the congratulations from the Central
Committee and Council of Ministers, insisted that we finish up our production
in space and bring the spacecraft back to Earth by any means. On 2 November,
after somehow setting up the spacecraft using the ionic system, the commands
were issued to start up the descent cycle programs. The ionic system slipped
up somewhere in the Brazilian Magnetic Anomaly, and the braking burn sent
the spacecraft toward Earth on a long, flat trajectory that emerged beyond
the limits of the authorized corridor. The APO system destroyed 7K-OK
vehicle No. 5. This time our tracking system and the anti-ballistic missile
system closely monitored the descent module’s descent trajectory. The vehicle
was blown up after it passed over Irkutsk. Had there been no APO system,
it might have landed 400 kilometers east of Ulan-Ude. On 3 November, we
boarded our planes and flew from the Crimea to Moscow....

COUTINHO INTROÇÃO ÀS PARTICULAS PRESAS AMAS  1805 KB Visualizar 

Langlois et Taberlet Le noyau terrestre PY5AAL.pdf - 1042 KB Visualizar

Li & Temeri The Electron Radiation Belt n PY5AAL.pdf - 48 KB Visualizar 

PINTO E OUTROS Novo Olhar Seguranca Sist Eletricos  py5aal.pdf - 384 KB Visualizar

Saboia Marques AMAS   py5aal.pdf - 512 KB Visualizar 

HEILMANN, RODRIGUES AVALIAÇ SIST DETEC DESC ATMOSF VLF ZEUS PY5AAL.pdf - 187 KB Visualizar 

LAIBIDA JR., AlbaryTeoria Cinética Veicular  .PY5AAL pdf - 477 KB Visualizar


BRUM, Christiano Garnett Marques; VARIABILIDADE DA ABSORÇÃO DE RUÍDO CÓSMICO VIA
RIÔMETRO E MODELAGEM NUMÉRICA DOS PROCESSOS ASSOCIADOS PY5AAL.pdf - 7932 KB Download
Para se obter uma descrição do campo geomagnético é preciso inclinar o eixo da Terra em aproximadamente 11°
e deslocá-lo em 500 km, a partir do centro geométrico terrestre, na direção 6,5°N e 162°E .
As linhas de campo magnético, quando comparadas à esfera terrestre, se aproximam mais
da superfície da Terra sobre a costa sudeste da América do Sul e sobre o
Oceano Atlântico, produzindo nesta região um mínimo absoluto na intensidade
do Campo Magnético Total. A região da AMAS é um grande
sorvedouro de elétrons. Tal fato foi observado há mais de 40 anos (Dessler,
1959) e, a partir de então, várias observações vêm sendo feitas através de
satélites, balões e técnicas de solo e inúmeros trabalhos teóricos têm sido
publicados, na tentativa de explicar o aumento do fluxo de partículas e os
efeitos aeronômicos decorrentes da mesma (Costa, 1991; Abdu et al., 1973;
Batista, 1975; Trivedi et al., 1973; Trivedi et al., 1975; Trivedi e da Costa, 1980;
Pinto e Gonzalez, 1988; Martin, 1972; Abdu et al., 1982)..
A região da AMAS é povoada por partículas energéticas que interagem
fortemente com os constituintes atmosféricos produzindo, nesta região, efeitos
ionosférico muito semelhantes àqueles observados nas regiões aurorais
(Gledhill e Van Rooyen, 1962; Doherty, 1971; Zimuda, 1966), tais como
precipitação de elétrons e partículas carregadas de origem solar, galáctica e de
partículas aprisionadas nos cinturões de radiação. Uma explicação para este
fato é que os elétrons aprisionados nas linhas de campo geomagnético, ao se
deslocarem sob a ação do efeito resultante da deriva, da curvatura e do
gradiente do campo magnético, atingem uma altitude mínima nesta região
(Benbrook et al., 1983).A principal fonte de injeção de
partículas desta região são os cinturões de radiação de Van Allen.
A injeção de elétrons por difusão radial pode atuar tanto sobre elétrons, com
valores de energia específicos, como para elétrons de todas as energias. Este
fato propicia a ocorrência de diferentes estruturas no espectro de elétrons
aprisionados. É importante observar que a injeção de elétrons na região da
AMAS é um processo contínuo, sendo intensificado em períodos
geomagneticamente ativos.
O principal processo de perda de elétrons para a atmosfera na região da AMAS
é a difusão em ângulo de arremesso (pitch angle). Tal difusão pode ser
causada por dois principais mecanismos: espalhamento Coulombiano dos
elétrons pelos constituintes atmosféricos (difusão colisional) e interações
ressonantes entre ondas e elétrons nas freqüências ciclotrônicas e de balanço
(difusão em ângulo de arremesso ressonante).
A difusão de ângulo de arremesso de elétrons é um processo aleatório e
contínuo. A intensificação deste processo na AMAS pode ser compreendida
com base no estudo do movimento dos elétrons aprisionados no campo
geomagnético. Assim, após percorrerem suas trajetórias ao redor da Terra e
chegarem à região da AMAS, os elétrons têm seus pontos de espelhamento
localizados em altitudes menores, intensificando sua interação com o meio
atmosférico desta região.
Apesar da grande variação da densidade atmosférica com a altura (variação
exponencial), um elétron pode demorar a interagir com os demais constituintes
atmosféricos, podendo permanecer aprisionado na sua trajetória adiabática
durante várias derivas, desde que não atinja a região crítica da AMAS, que está
situada em torno de 100km de altitude, conforme estabelecido por Berger e
Seltzer (1972), como uma fronteira entre as regiões de elétrons aprisionados e
de elétrons em precipitação. Isto é equivalente à definição de um ângulo de
arremesso equatorial crítico e que limita o cone de perdas de forma que um
elétron se precipita quando atinge tal ângulo. Ao entrar na atmosfera, o elétron
irá sofrer colisões com os constituintes atmosféricos locais, atuando em
escalas de tempo onde os seus invariantes adiabáticos serão violados. O
resultado destas colisões é a difusão gradual dos elétrons para dentro do cone
de perdas com uma conseqüente diminuição na altitude de espelhamento que
ocorre até o instante da sua precipitação.
A evolução do espectro de energia dos elétrons, desde o seu aprisionamento
pelo campo geomagnético até o instante de sua precipitação (menor ou igual à
aproximadamente 100 km de altura), pode ser qualitativamente resumida nas
seguintes considerações: (1) o espectro de energia dos elétrons evolui para
uma forma de equilíbrio tipicamente exponencial e decrescente; (2) dado que a
profundidade atmosférica em 100 km de altitude é aproximadamente 3.10-4
g/cm2, os elétrons com energia menor do que 10 kev não alcançam a altura de
100 km (Berger e Seltzer, 1964); (3) considerando-se a inclinação das linhas de
campo magnético na região da AMAS é possível, em primeira aproximação,
supor uma distribuição isotrópica em 100 km, na qual a distribuição angular
tende para uma forma de equilíbrio; (4) estruturas tais como os picos no
espectro de elétrons de alta energia (Berger e Seltzer, 1964), embora sofram
degradação, tendem a manter-se ao longo da difusão devido à menor perda de
energia dos elétrons de alta energia ; e (5) o fluxo de elétrons tende a diminuir
devido, principalmente, ao efeito de espelhamento e ao espalhamento de 180o,
os quais são dependentes da energia eletrônica.
Os pontos de espelhamento das partículas aprisionadas em uma camada L, na
região da AMAS, encontram-se muito baixos (<100km) (Williams e Kohl, 1965;
Roederer et al., 1967). A deriva de prótons para oeste produz uma
concentração maior destas partículas no lado leste da AMAS, de forma que o
fluxo precipitado é mais intenso à leste da AMAS e diminui rapidamente na
direção oeste. Como exemplo desta variação, o fluxo de prótons para L=2 no
hemisfério sul atinge um pico aproximadamente 35 vezes maior do que o fluxo
médio precipitado para o mesmo valor de L no hemisfério norte. A Figura 1.22
apresenta a variação do fluxo de prótons precipitado em função de L e da
longitude para os dois hemisférios (Torr et al., 1975).
Um fluxo de elétrons maior que 10 partículas.cm-2.s-1.sr-1 com uma energia
≥300keV é suficiente para produzir ionização diurna a uma altitude de 72 km
(Zimuda, 1966). Para o mesmo fluxo produzir ionização noturna em
aproximadamente 90km de altura, são necessários elétrons de menor energia
(Ee ≥40keV). Kikuchi e Evans (1982) afirmam que os elétrons de 300keV são
importantes fontes de ionização, tanto para os horários diurnos quanto para os
noturnos e estimou um fluxo mínimo de 40 elétrons.cm-2.s-1.sr-1 como sendo o
fluxo necessário para produzir desvios diurnos na propagação das ondas de
VLF, por exemplo. A Figura 1.25 ilustra a relação entre a variação da altura
ionosférica e o fluxo de prótons observado, através da altitude de reflexão das
ondas de VLF, para energias iguais ou maiores do que 20MeV (Kossey et al.,
1983).
Existem evidências experimentais que confirmam uma precipitação constante
de elétrons e prótons energéticos na região da AMAS (Gledhill, 1976; Abdu e
Batista, 1977). Quanto à precipitação de elétrons, esta afirmação é
inquestionáve
l. Porém para os prótons, há evidências que descartam tal
possibilidade, pois o fluxo de prótons, tanto em períodos calmos como em
períodos perturbados, é desprezível (Pieper et al., 1965; Gough, 1975). Por
outro lado, existem casos em que a presença dos prótons no fluxo de
partículas precipitadas na AMAS é aceita e discutida (Freden e Paulikas, 1964;
Vernov et al., 1967; Torr et al., 1975).

http://mtc-m16.sid.inpe.br/col/sid.inpe.br/jeferson/2004/08.04.16.30/doc/publicacao.pdf


English et all apollo protection radiation py5aal.pdf - 5463 KB Visualizar 
The problem of protection against the natural radiations of the Van Allen belts
was recognized before the advent of manned space flight. The simplified solution is to
remain under the belts (below an altitude of approximately 300 nautical miles) when in
earth orbit and to traverse the belts rapidly on the way to outer space. In reality, the
problem is somewhat more complex. The radiation belts vary in altitude over various
parts of the earth and are absent over the north and south magnetic poles. A particularly
significant portion of the Van Allen belts is a region known as the South Atlantic
anomaly (fig. 2). Over the South Atlantic region,the geomagnetic field draws particles
closer to the earth than in other regions of the globe. The orbit inclination of a spacecraft
determines the number of passes made per day through this region and, thus,
determines the radiation dose that will accompany these passes for a set altitude and
~ spacecraft shielding.A major camplication concerningradiation stability within
 the belts (includingthe South Atlantic anomaly portion) is a
result of high-altitude nuclear detonations.
In 1962, the United States detonated a1. 5-megaton thermonuclear device (Project
Starfish) in a portion of the Van Allen belt region and caused the radiation levels
within the belts to rise significantly. By 1969, the high -energy electron component
of the injected radiation had decayed to only
one-twelfth of the 1962 intensity. small amount of time spent in earth orbit
and the rapid traverse of the radiation belts during Apollo missions have minimized
astronaut radiation dose from the remaining Starfish electrons. However, recur -
rence of high-altitude nuclear testing wouldThe have a significant impact on Apollo earth-orbit 
operations, and this possibility has been factored into radiation-protection planning 
for Apollo space missions. Sources of current intelligence information on  nuclear-device
 testing are available to  the NASA,and these sources are ready 
to assist in the real-time management of any contingencythat might be caused 
by the high-altitude detonation of a nuclear device.
Particles within the Van Allen belts spiral around the earth magnetic lines offorce and, 
therefore, display directionality. This directionality varies continuously in
angular relationship to the trajectory of the spacecraft. Therefore, dosimetry instru -
mentation in the Van Allen belts must use relatively omnidirectional radiation sensors
so that the radiation f l u will be measured accurately. 
The Van Allen belt dosimeter (VABD) (fig. 3) was designed specifically 
for Apollo dosimetry within these radiation belts and has proved satisfactory because 
dose values derived from its greater than 180" radiation acceptance angle have correlated 
well with doses indicated by postflight analyses of passive dosimeters worn by the crewmen. 
The nuclear -particle -detectionsystem (NPDS) (fig. 4) was designed to have a 
relatively narrow acceptance angle and was intended to measure the isotropic proton 
and alpha particles derived from solarparticle events. Experience with the NPDS within the highly 
directional radiation fields of the Van Allen belts has emphasized the difficulty 
in determining true flux levels using a detector of narrow angle response, 
There are two problems in determining flux levels. First, orientation of the spacecraft relative 
to the direction of the impinging particles is not precisely known at all times.
inaccuracy would result from the high statistical  error inherent with low counting rates
when the detector is pointed away from the direction of particle flux.Second, even if 
orientation were precisely known,
A compromise in VABD design was required for Apollo flammability considerations,
and this compromise resulted in the use of aluminum as a replacement for
tissue -equivalent plastic in the ionization-chamber  walls, Aluminum is a satisfactory
replacement for tissue -equivalent plastic only if electron secondary radiation (brems -
strahlung) is a small portion of the total radiation 
dose (as in the Apollo Program).Chambers of tetrafluoroethylene plastic would be 
preferable to aluminum if flammability remains a design factor for future missions,
 A detailed discussion of radiation dosimetry considerations for post-Apollo missions is contained 
in references 2 and 3. No major solar -particle events have
occurred during an Apollo mission (fig. 1). Although much effort has been expended in
the field of solar -event forecasting, individual eruptions from the solar surface are
impossible to forecast. The best that can be provided at this time is an estimate of
particle dose, given visual or radiofrequency (RF) confirmation that 
an eruption has occurred. A system of solarmonitoring stations, the Solar Particle
Alert Network (SPAN), provides a NASAsponsored network of continuous data on
solar -flare activity. The various components of this network are described in the
appendix. Approximately 20 percent of the largest solar flares (importance 2 bright
or larger) will result in particle fluxes in the earth/moon region that can be related
in intensity to early RF or visual characteristics. A warning interval of from less
than one to several hours (typically, 2 to 4 hours) is obtained between the 
RF/visual indication and the appearance of particles
in the earth/moon region. Because only approximately 20 percent of the flares result
in particle events, it is not necessary to change normal mission procedures on the
basis of RF or visual observations alone. Rather, radiation sensors on board solarorbit
and earth-orbit satellites, as well as on board the Apollo spacecraft itself, are
used to confirm the particle event. Only after the appearance of particles is confirmed
would action be taken to protect the crewmen. For a typical event, approximately
8 hours would be available from the time particles are confirmed to the time of peak
radiation dose. Details concerning effects of solar-particle events on various phases

Campbell et McCandless Introduction to Space Sciences spacecraft applications py5aal.pdf - 5701 KB Visualizar
presence of areas of radiation around the earth was discovered by Dr.
James Van Allen using instruments aboard the early U.S. V-2 test flights
and, later, Explorer series satellites. It was found that some of the charged
particles present in space were able to enter the magnetosphere and become
trapped within the geomagnetic field. The gainfloss mechanics of this phenomenon
is still not completely understood, but the levels, dispersion, and
behavior of the trapped particles have become well described.
Early representations of “belts” of radiation surrounding the earth are
better described by distributions of particles within the magnetosphere
which follow closely the geomagnetic lines of flux. Areas of different
concentrations exist due to the types of particles (protons and electrons)
and associated energy levels. More energetic particles are generally
trapped closer to the earth, and the major concentrations of particles occur
around the equator where the minimum value of magnetic field flux
occurs. Figure 4-1 1 shows this distribution of trapped particles around the
earth in terms of particle types and energy levels (1E2 indicates 1 x lo2
MeV or mega-electron volts of energy). In some regions, the level of radiation
due to these trapped particles is sufficient to be disruptive to spacecraft
operations and hazardous to humans.
Although caught in the earth’s magnetic field, these particles are far
from stationary. Motion of these energetic charged particles is a combination
of spiraling around the magnetic field lines while bouncing from pole
to pole along the lines. A slower drift around the equator also occurs.
When these particles interact with the ionosphere as they spiral in towards
the earth in the vicinity of the poles, they produce the auroral phenomena
known as the “northern lights” in the northern hemisphere. A more serious
effect of these motions is the contribution to atmospheric heating by
particle precipitation in the auroral zones and by the electric currents
flowing at high and low latitudes.
The off-set geometry of the geomagnetic field, produces an asymmetry in the radiation belts
 whichresults in an area where the belts are closer to the earth’s surface. This area occurs
 just off the coast of Brazil in the Atlantic Ocean and is known as the 
South Atlantic Anomaly. Spacecraft passing over this area experience a significantly 
increased radiation dosage sufficient to cause concern when operating in this region.
spacecraft systems as they turn on and off. Spacecraft also continuously
emit heat, especially toward the “cold” (absorptive) blackness of space.
For some applications, certain spacecraft parts may always point toward
the sun while others may always point toward space. Within certain
defined limits, the craft must be able to balance the temperatures of all its
components. Several spacecraft have been lost or impaired due to the
freezing of propellant lines or the heating of an electronic component to
the point of failure.
As we have seen, the space environment is full of charged materials,
trapped solar particles, and ionized atmospheric constituents as the major
examples. Also, as they travel through space, orbiting spacecraft cut
through magnetic field lines of flux which tends to make charges want to
move. Operation within such an electrically rich and magnetically dynamic
environment can result in a buildup of charges on the surfaces of the
spacecraft to the point at which a current flow or discharge from one component
to another may result in damage to the system.
Some of the higher-energy particles present in space can penetrate the
skin and components of a spacecraft. These may deposit an electrical
charge inside electrical components or may even change the physical
structure of materials. Sudden depositions of electrical charge in computer
logic circuits or memories can corrupt data or even disrupt operation of
the satellite if a “phantom command” is sensed from such an event.
Buildup of radiation damage to semi-conductor materials can cause computer
chips to degrade to the point where commands may no longer be
able to be processed. Satellite operators have to be especially vigilant for
signs of these effects during periods of high solar activity.

Brun et Ritchie Astronautics Aeronautics astronauts  1975  py5aal.pdf - 7461 KB Visualizar
Scientists believed that light flashes observed by Skylab 4 crew members
during their 16 Nov. 1973 to 8 Feb. 1974 mission as they flew
through the South Atlantic Anomaly-a slight asym etry in the
usually low over Brazil-were a previously unsuspected form of
radiation, Science magazine reported. The radiation seemed to consist
of atomic nuclei heavier than hydrogen which, when stripped of
electrons, would carry multiple positive electric charges.
The astronauts had seen the flashes when the spacecraft cabin
was dark and they were preparing for sleep. Scientists suspected
that the flashes were stimulated within the retina of the eye by the
high-energy cosmic-ray particles. Normally earth was shielded from
cosmic rays by the magnetic field, but strong penetrating cosmic rays
could reach as far into the field as the Skylab orbit.
Because the magnetic-field shielding of the earth weakened toward
the geomagnetic poles, it was possible to predict variations in cosmicray
exposure as Skylab moved away from the poles. During two test
periods, light-flash observations of Astronaut William R. Pogue
showed a close correlation with exposure variations

Emme Astronautics Aeronautics 1966 chronology  py5aal.pdf - 13578 KB Visualizar 
PEGASUS I, 11, and 111 meteoroid detection
satellites-launched Feb. 16, May 25, and July 30, 1965,
respectively-had provided full year of data which defined “more
precise1 than ever before” near-earth meteoroid environment, NASA
reportel Data-including cumulative count of 1,000 “hits” on target
plate thickness, identification and location of specific panel hit, attitude
of spacecraft with respect to earth and sun at impact time, and time of
penetration-confirmed “protective adequacy” of Apollo manned lunar
landing spacecraft against meteoroids ; provided designers of future
spacecraft with guidelines on probability of meteoroid penetrations ;
and improved mapping of South Atlantic anomaly by measuring
electron radiation density.

rumerman Nasa Historical databook VII  py5aal ch1.pdf - 652 KB Visualizar 
NASA began operating as the nation’s civilian space agency 
in 1958 after passage of the National Aeronautics and Space 
Act. It succeeded the National Advisory Committee for 
Aeronautics (NACA). 
The new organization was charged with preserving the role of 
the United States “as a leader in aeronautical and space science 
and technology,” expanding our knowledge of Earth’s atmosphere 
and space, and exploring flight both within and outside the 
atmosphere.The decade from 1989 to 1998 was extremely productive, 
as NASA added to its already considerable list of achievements. 
The decade was marked by assembly of the first orbiting Space 
Station components, launch of the first two Great Observatories, 
and an outstanding record of safe and fruitful missions.

rumerman  Nasa Historical databook VII  py5aal ch2.pdf - 3864 KB Visualizar 
The Atlas I was the first of a new family of launch 
vehicles that could boost payloads into low-Earth 
orbit, geosynchronous-Earth orbit, and on interplanetary
 trajectories. The launch vehicle was very similar to 
the Atlas G Centaur, and it included two boosters, a 
sustainer, two vernier single-start engines, and a 
Centaur upper stage. An interstage adapter separated 
the Atlas stage from the Centaur. The vehicle had 
two new payload fairings, incorporated significant 
improvements in the guidance and control systems, 
and replaced analog flight control components with 
digital units interconnected with a digital data bus. 
Figure 2–11 shows an Atlas I. Table 2–65 lists 
Atlas I characteristics.The first Atlas I flight 
took place on July 25, 1990, with the launch of 
the Combined Release and Radiation Effects Satellite (CRRES), 
a joint NASA-U.S. Air Force project. The final 
Atlas I launch took place on April 25, 1997, with 
the launch of GOES-10 into geosynchronous orbit. 
Although launch parameters varied slightly depending 
on launch date, launch time, and payload weight, T
able 2–66 presents a typical launch sequence for a 
geosynchronous mission.

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The spacecraft structure consisted of a main body 
and six solar panels. A combination of passive and 
active methods provided spacecraft thermal control. 
Multilayer thermal blankets and thermal radiators
 were used for passive thermal control. Heaters with 
thermostats controlled the temperature of the batteries
, the star tracker, and the SXT.The spacecraft 
flew in a slightly elliptical low-Earth orbit. 
During five to six of its orbits each day, Yohkoh 
passed through the radiation belts of the 
South Atlantic Anomaly where the BCS, HXT, and most 
channels on the WBS (all of which used high voltages) 
had to be turned off to avoid damage to the instruments 
and satellite.Observations from the instruments were 
stored in the Spacecraft Bubble Data Recorder (BDR). 
Approximately 50 megabytes of data were accumulated 
each day and stored in the 10-megabyte on-board tape 
recorder. To optimize the recorder, the BDR could operate 
at several bit-rates—high, medium, and low. Switching 
between the bit-rates was controlled both automatically 
and by on-board deferred commands. This switching was 
necessary because the high bit rate held only 42 minutes 
of data. Some overwriting of data was permitted.The 
satellite operated in several spacecraft and subsystem 
modes. The two modes of principal interest were the 
Quiet Mode and Flare Mode. Switching between these 
two particular modes was controlled by a flare flag 
generated by the WBS. Yohkoh’s operating mode determined 
which instruments could collect the data and how much 
they could collect. Generally, more HXT data was taken 
during the Flare Mode than during the Quiet Mode.

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Three months later on 31 January 1958, the Army came through. Explorer 1 was
 launched into orbit atop a Jupiter C IRBM to become America’s first artificial
 satellite. In addition to a 108 MHz transmitter (which operated for a remarkable 
113 days), the 68-kilogram (31-pound) satellite had onboard an experiment
 devised by Professor James A. Van Allen of the University of Iowa to detect 
charged particles in Earth’s magnetic field. In time, telemetry downlinked
 from the first four Explorer satellites led to the discovery of the Van Allen 
Radiation Belts, hailed as the single most important discovery of the IGY.

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Take the seismometer network emplaced by Apollo 12, 14, 15,
 and 16. It enabled the location of impacts and moonquakes 
to be determined very precisely. The network of three 
Lunar Surface Magnetometers enabled the study of solar 
wind plasma movement by tracing its magnetic field. 
Closing out the program, Apollo 17 carried an enhanced 
package of surface experiments. With nuclear power from
 the RTGs, ALSEP transmissions were received by NASA’s 
Spaceflight Tracking and Data Network for years after 
the last astronauts had left the Moon.

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Besides the HST and CGRO,there is the Chandra X-ray 
Observatory,  launched on 23 July 1999 aboard STS-93 
and the Space Infrared Telescope Facility (SIRTF) 
whose primary mission, as its name implies, is observation 
of the infrared spectrum. (The SIRTF, launched 
on 25 August 2003 aboard a Delta II rocket, was later
 renamed the Spitzer Space Telescope.)77 Aside from 
performing each telescope’s own mission, most of which 
cannot be replicated by ground observatories, the 
Great Observatories program allows the four to 
synergistically interact with each other for greater 
combined scientific returns.Each astronomical object 
in the sky radiates in different wavelengths. 
But by training two or more observatories on an object,
combined data can be returned to paint a much more 
comprehensive picture than is possible with just a 
single instrument.After its deployment from STS-37,
 the CGRO operated as advertised for almost a year, 
returning more data on that portion of the electromagnetic 
spectrum than the previous six decades put together. 
But in March 1992, it suffered a failure of its two onboard 
tape recorders which restricted downlinks of scientific 
data to real time only. With the tape recorders gone, 
CGRO was able to relay only slightly more than half of
 the science data it collected, because it could not point 
at a TDRS all the time. While TDRSS coverage had been 
about 65 percent of each orbit, scientists could not 
even collect that percentage of data anymore because 
Compton’s instruments had to be turned off during the
 part of each orbit when it passed through the elevated 
background radiation of the South Atlantic Anomaly—a 
region of significantly increased space radiation 
experienced by satellites passing over the South Atlantic 
Ocean. This reduction in data return presented an 
obstacle to the Goddard science team. NASA, understandably,
 wanted to get back to the point where all of the data could 
be retrieved. Furthermore, real-time data dumps could only
 be done at the very slow rate of 32 kilobits-per-second 
whereas the playback rate was 512 kilobits-per-second.

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Earth is surrounded by a close-to-spherical 
magnetic field, the magnetosphere.According 
to what we know today,it is being generated 
by actions deep in Earth’s interior where 
conducting liquid metals are kept in motion
 by the forces of convection, Coriolis 
(centrifugal), and gravitation. Just as 
the charged windings in the coil of a 
generator puts out a magnetic field, these 
masses create Earth’s magnetic field. This 
field protects the planet from space radiation 
by deflecting high energy particles from 
deep space or by capturing them in the 
Van Allen Belts. Of these belts, discovered 
by the first U.S. satellite, Explorer 1 in 1958, 
there are two, one closer and the other farther 
away. Both surround Earth like a doughnut. 
However, at a certain location over the 
South Atlantic Ocean between Brazil and Africa, 
the shielding effect of the magnetosphere is 
not quite spherical but shows a “pothole” or 
a dip, which scientists explain as a result 
of the offset of the center of the magnetic 
field from the geographical center of Earth 
(by some 450 kilometers or 280 miles), as well 
as the displacement between the magnetic and 
geographic poles of Earth.For low-Earth orbiting 
satellites inclined between 35 and 60° with 
respect to the Equator, this oddity, called 
the South Atlantic Anomaly, becomes important 
since spacecraft in those orbits periodically 
pass through that zone of reduced natural 
shielding and thus spend a few minutes during 
each orbit exposed to much higher cosmic particle
 flux.Thus, vehicles in such orbits require higher
 shielding for the crew. It is also of concern in 
the design of space-hardened electronics which are
 degraded faster by higher particle fluxes. 
The design of the International Space Station, 
for instance, takes this effect into account.

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Kopp, G.; Lawrence, G and Rottman, G.Solar Flares NASA Video from 2003 ( (2005). "The Total Irradiance Monitor (TIM): Science Results". Solar Physics 230: 129–139. doi:10.1007/s11207-005-7433-9.http://adsabs.harvard.edu/abs/2005SoPh..230..129K.