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3 A Brief History of Space Flight
of the Voyager-1 had ceased working, so the indirect measurement was required to
support a correct decision. In the meantime, the NASA released audio renditions of
these plasma waves, which represented the first sounds to be captured in interstellar
space.
It is noted that the Voyager-1 having left the solar system with the heliosphere
are two different expressions. The solar system is usually defined as the vastly larger
region of space populated by bodies that orbit the Sun. As of April 2020, the Voyager1 is traveling the distance of 148 AU away from the Earth, which is a distance of
slightly more than one sixth to the aphelion of Sedna. The Sedna is also known as
90377 Sedna, a small celestial body discovered in 2003 in the outer reaches of the
solar system, with an aphelion of 937 AU and a perihelion of 76 AU. Apparently,
the spacecraft has not yet entered the Oort cloud with a distance of above 50,000
AU away from the Sun, which is regarded by astronomers as the outermost zone of
the solar system. So, for the gravitational boundary of the solar system defined in
astronomy, the Voyager-1 is still within the range populated by the Sun’s gravity,
but it has crossed through the physical boundary of the solar system and entered
interstellar space.
3.6.6 New Horizons Probe
In July 2002, the NASA initiated an Integrated Exploration Strategy to tackle specific
solar system exploration goals identified as top priorities by the planetary science
community, known as New Frontiers Program, whose strategy is to explore the solar
system with the medium-class spacecraft missions that conduct high-science-return
investigations, and to deeply understand the solar system. The Program builds on the
innovative approaches used in the NASA’s Discovery Program, but provides a mechanism for identifying and selecting strategic missions that can not be accomplished
within the cost and time constraints of the Discovery Program. At present, the New
Frontiers Program mainly includes four missions. The first mission is the New Horizons probe launched in January 2006, to obtain a close look at the Pluto and its moons
and further to enter into the Kuiper Belt, which help scientists answer basic questions
about the surface properties, geology, interior makeup and atmosphere of the ancient,
icy mini-worlds in that vast region. The second mission is the Juno probe launched in
August 2011, to explore the Jupiter in detail, such as the gas giant’s gravitational and
magnetic fields, vast magnetosphere, intense aurora and the swirling clouds that form
the Jupiter’s colorful, trademark atmosphere, which help scientists understand the
history of the solar system and provide new insight into how planetary systems form
and develop in the Galaxy and beyond. The third mission is the Origins, Spectral
Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx)
launched in September 2016, to retrieve a sample of an asteroid and carry it to the
Earth for further study, which will help scientists understand the planetary formation
and the origin of life, and aid in understanding asteroids that can impact the Earth.
The OSIRIS-REx is currently orbiting the asteroid, 101955 Bennu, and will spend
3 A Brief History of Space Flight
of the Voyager-1 had ceased working, so the indirect measurement was required to
support a correct decision. In the meantime, the NASA released audio renditions of
these plasma waves, which represented the first sounds to be captured in interstellar
space.
It is noted that the Voyager-1 having left the solar system with the heliosphere
are two different expressions. The solar system is usually defined as the vastly larger
region of space populated by bodies that orbit the Sun. As of April 2020, the Voyager1 is traveling the distance of 148 AU away from the Earth, which is a distance of
slightly more than one sixth to the aphelion of Sedna. The Sedna is also known as
90377 Sedna, a small celestial body discovered in 2003 in the outer reaches of the
solar system, with an aphelion of 937 AU and a perihelion of 76 AU. Apparently,
the spacecraft has not yet entered the Oort cloud with a distance of above 50,000
AU away from the Sun, which is regarded by astronomers as the outermost zone of
the solar system. So, for the gravitational boundary of the solar system defined in
astronomy, the Voyager-1 is still within the range populated by the Sun’s gravity,
but it has crossed through the physical boundary of the solar system and entered
interstellar space.
3.6.6 New Horizons Probe
In July 2002, the NASA initiated an Integrated Exploration Strategy to tackle specific
solar system exploration goals identified as top priorities by the planetary science
community, known as New Frontiers Program, whose strategy is to explore the solar
system with the medium-class spacecraft missions that conduct high-science-return
investigations, and to deeply understand the solar system. The Program builds on the
innovative approaches used in the NASA’s Discovery Program, but provides a mechanism for identifying and selecting strategic missions that can not be accomplished
within the cost and time constraints of the Discovery Program. At present, the New
Frontiers Program mainly includes four missions. The first mission is the New Horizons probe launched in January 2006, to obtain a close look at the Pluto and its moons
and further to enter into the Kuiper Belt, which help scientists answer basic questions
about the surface properties, geology, interior makeup and atmosphere of the ancient,
icy mini-worlds in that vast region. The second mission is the Juno probe launched in
August 2011, to explore the Jupiter in detail, such as the gas giant’s gravitational and
magnetic fields, vast magnetosphere, intense aurora and the swirling clouds that form
the Jupiter’s colorful, trademark atmosphere, which help scientists understand the
history of the solar system and provide new insight into how planetary systems form
and develop in the Galaxy and beyond. The third mission is the Origins, Spectral
Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx)
launched in September 2016, to retrieve a sample of an asteroid and carry it to the
Earth for further study, which will help scientists understand the planetary formation
and the origin of life, and aid in understanding asteroids that can impact the Earth.
The OSIRIS-REx is currently orbiting the asteroid, 101955 Bennu, and will spend