SPACE.com compiled a list of the major
observatories currently up doing space-based astronomy. The list excludes
rovers, orbiters and planetary probes not doing traditional telescope
observations.
Key for
entries below:
Telescope Name / Agency / Year Launched / Wavelengths / Primary Targets
Hubble
Space Telescope / NASA, ESA / 1990 / Visible, UV, Near-IR / Deep Space Objects
The granddaddy of space telescopes, Hubble
has been observing from Earth orbit for more than 19 years. Hubble, the first
of NASA's Great Observatories, has revolutionized astronomy, providing stunning
images of countless cosmic objects and giving astronomers their most distant
views of the universe with the Hubble Deep Field and Ultra Deep Field. Hubble
has shed light on the scale of the universe, the life cycle of stars, black
holes, and the formation of the first galaxies. Currently receiving its fifth
and final makeover, Hubble is expected to last at least another five years, hopefully
overlapping with its successor, the James Webb Space Telescope.
Chandra
X-ray Observatory / NASA / 1999 / X-ray / Various
The third
of NASA's four Great Observatories, Chandra is the world's most
powerful X-ray telescope. Chandra, named for Indian-American physicist
Subrahmanyan Chandrasekhar, examines the X-rays emitted by some of the
universe's strangest objects, including quasars, immense clouds of gas and dust
and particles sucked into black holes. X-rays are produced when matter is
heated to millions of degrees. Chandra has teamed up several times with other
telescopes, including Hubble, to take composite images of galaxies and other
denizens of the cosmos. It has found previously hidden black holes, provided
observations of the Milky Way's own supermassive black hole, Sagittarius A*,
and even taken the first X-ray images of Mars.
Spitzer
Space Telescope / NASA / 2003 / IR / Distant and Nearby Objects
Spitzer was
the last of the Great Observatories to be launched and gathers the infrared
radiation emanating from cosmic objects, including faraway galaxies, black
holes and even comets in our own solar system. (Infrared radiation is hard to
observe from the ground because it is largely absorbed by the Earth's
atmosphere.) Spitzer
was the first telescope to see light from an exoplanet, which it was not
originally designed to see; it took the temperatures of so-called "hot
Jupiters" and found that not all of them are really hot. Spitzer is about
to use the last of the liquid helium coolant that has kept its instruments
chilled for the past 5.5 years. Spitzer's instruments will be able to keep
going for another two years, meanwhile, the European Space Agency's Herschel
telescope is designed to pick up where Spitzer left off.
Herschel
Space Observatory / ESA & NASA / 2009 / Far-IR / Various
Herschel
was lobbed into space on May 14, along with the Planck telescope. Herschel will
be the largest, most
powerful infrared telescope, looking at the far-infrared to sub-millimeter
wavelengths of light generated by some of the coldest objects in space.
Herschel is designed to look for water, both in nearby comets and faraway dust
clouds, and will also peer into the womb of star formation. Astronomers expect
to catch a glimpse of baby stars in the act of forming — something they have
never before been able to see. Like its predecessor Spitzer, Herschel will also
take a peek at a few exoplanets.
Planck
Observatory / ESA / 2009 / Microwave / Cosmic Microwave Background
Herschel's launch
partner, the
Planck Observatory, will be concentrating on the microwave light of the
universe. Planck will be looking at the remnants of the first light to shine
freely in the universe, the Cosmic Microwave Background (CMB). Planck will
follow in the footsteps of NASA's Cosmic Background Explorer (COBE) and WMAP,
mapping the CMB and providing the most detailed measurements of the temperature
variations in the remnant light. Planck will also probe the mysteries of dark
matter and dark energy and map the magnetic field of the Milky Way in 3-D.
Kepler Mission / NASA / 2009 / Visible / Extrasolar planets
Also new to
the space scene is Kepler, NASA's new planet-hunting
telescope that will specifically be searching for other Earth-like planets
in the galaxy. Kepler will be looking for characteristic variations in the
light from a pre-selected target group of 100,000 stars. Dips in the light from
the stars can indicate a planet passing in front of the star (from Earth's
perspective). Astronomers are hoping that Kepler fill find planets in the
stars' habitable zones, where temperatures are just right for liquid water to
exist. After getting settled into its new orbital home, Kepler officially began
its search in May. First light from the telescope came on April 16.
Fermi
Gamma-ray Space Telescope / NASA / 2008 / Gamma-ray / Various
Fermi
(formerly GLAST) joined the ranks of the space telescopes last summer, and has
already given astronomers their best-ever view of the most extreme energy in
the cosmos: gamma
rays. Gamma rays can reveal some of the most energetic and mysterious
events in the universe, including dark matter, black holes and spinning
pulsars. Not longer after arriving in orbit, it took an all-sky map that shows
gamma rays from numerous sources, including our own sun. The Fermi team used
the map to crate a "top 5" list of gamma ray sources. Fermi has also
detected the highest energy gamma ray burst yet.
Swift
Gamma Ray Burst Explorer / NASA / 2004 / Gamma ray, X-ray, UV, Visible /
Various
Like Fermi,
Swift also scans the sky for gamma rays, specifically looking for gamma-ray
bursts (GRBs), the most powerful explosions in the universe. GRBs flash for
just a few seconds before sliding into an afterglow of X-ray, ultraviolet and
visible light. Swift can detect a GRB and within a minute point itself at the
event for quick observations, with its instruments following along as the
burst's light moves through the spectrum. In 2007, Swift spotted a GRB with the
longest lived afterglow yet recorded, more than 125 days. Swift has also
recorded the most distant cosmic explosion ever seen, a gamma-ray burst from a
star that died when the universe was only 630 million years old, or less than 5
percent of its present age.
INTEGRAL
/ ESA / 2002 / Gamma ray, X-ray, Visible / Various
ESA's
International Gamma-Ray Astrophysics Laboratory was the first space observatory
that can simultaneously observe objects in gamma rays, X-rays and visible
light. INTEGRAL,
like Fermi and Swift, is tasked with looking for gamma-ray bursts, but it also
keeps an eye out for supernova explosions and peers into regions in the universe
thought to contain black holes. Astronomers hope that Integral's observations
will help them learn more about how elements are formed when a star dies and
could help us better understand the massive black hole lurking in the center of
our own galaxy.
XMM-Newton
/ ESA / 1999 / X-ray / Various
Moving to
shorter wavelengths in the electromagnetic spectrum, we have the X-ray
Multi-Mirror Mission – Newton, named in honor of Sir Isaac Newton. XMM-Newton's
instruments allow it to make long, uninterrupted observations; it can detect
more X-ray sources than any previous satellite. XMM-Newton
has found detected galaxies billions of light years away from Earth, observed
magnetars (a strange type of neutron star) and star-forming regions, and
investigated what happens in and around black holes.
GALEX /
NASA / 2003 / UV / Galaxies
The main
mission of NASA's Galaxy
Evolution Explorer is to help better understand the formation of galaxies.
It studies the shape, brightness, size and distance of galaxies beyond the
universe. Since its launch, GALEX has imaged more than a half-billion objects
across two-thirds of the sky. The telescope's first observation, of the sky in
the constellation Hercules, was dedicated to the crew of the Space Shuttle
Columbia. GALEX has detected star formation in unexpected regions of the
universe and spotting Mira, a fast-moving older star called a red giant.
COROT /
CNES & ESA / 2006 / Visible / Extrasolar planets
Now we're back
down to the spectrum to the wavelengths we humans can see. The Convection
Rotation and planetary Transits mission has two objectives: to search for
extrasolar planets that orbit close to their sun and to conduct stellar
seismology. COROT spotted its first exoplanet in 2007. Earlier this year, COROT
scientists made a controversial claim that the telescope had discovered the smallest
known exoplanet. In 2008, it found an object that scientists think could
either be a brown dwarf (a failed star) or a planet.
Solar
& Heliospheric Observatory / NASA & ESA / 1995 / Optical-UV, Magnetic /
Sun and Solar Wind
While other
telescopes are busy looking at distant stars, SOHO is focused on our own. SOHO was designed to study the structure and dynamics of the interior of the sun, as well
as the solar wind, the stream of charged particles ejected from the sun's upper
atmosphere. Understanding these solar phenomena is key to making better
predictions of space weather, such as solar flares, which can affect electrical
grids and communication networks here on Earth. To date, SOHO has taken the
first images
of the sun's convection zone, shown the structure of sunspots below the
sun's surface, and discovered new phenomena, such as solar tornadoes. SOHO has also spotted 1,500 new comets.
STEREO /
NASA / 2006 / Visible, UV, Radio / Sun and Coronal Mass Ejections
Another
solar observer, the STEREO (Solar Terrestrial Relations Observatory) mission is
actually two separate spacecraft that after launch moved apart so that one
trails Earth and the other leads it. These positions allow for stereoscopic
imaging of the Sun and solar phenomena. STEREO has taken 3-D images of solar
storms known as Coronal Mass Ejections (CMEs). These powerful solar eruptions
are a major source of the magnetic disruptions on Earth, interrupting satellite
operations, communications and power systems.
Other
missions
There are
of course other missions being pursued by NASA, ESA and other space agencies;
some are already up and space, while others are just in the planning phases.
One of the
big missions scientists are anticipating is the James Webb Space Telescope,
which will be the successor of Hubble. In fact, "it is designed
specifically to build on Hubble's legacy," said Jon Morse, NASA's
Astrophysics Division director.
It will search
for light from the first stars and galaxies which formed in the universe after
the Big Bang to better understand how stars and star systems form. The project
has met some delays and cost overruns, and the telescope is currently slated to
launch in 2013.
"That
will be a decade of frontier astronomy with JWST," Morse said.
But JWST
isn't the only telescope in the works, and Morse expects this golden age to
continue for some time.
"There
will continuously be interesting things to do with missions of all sizes, so I
look forward to an exciting portfolio well into the coming decades," Morse
said.
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