20 ASTRONOMY • MARCH 2020
the imperfection was more
than disheartening.
Fortunately, NASA
designed Hubble to be
serviced regularly. On
December 3, 1993, a teamof seven astronauts rocketed
into orbit aboard the space
shuttle Endeavour. Their
most important task: Install
two new instruments that
would serve as “eyeglasses”and transform fuzzy images
into crystal clarity.
Four subsequent servicing
missions — the final one in
May 2009 — have completely
revamped the observatory and
made it into a 21st-century
science machine. It has cap-
tured more than 1 million
images of the cosmos, explor-
ing objects as near as the
Moon and as distant as some
of the first galaxies to form in
the early universe. And it has
studied myriad examples of
almost every type of target
that lies between.Planetary weather
satellite
When people think of Hubble,
most picture stunning images
of Milky Way nebulae and
colorful galaxies. But scien-
tists often set their sights
closer to home. No spacecraft
has visited Uranus or
Neptune since the 1980s,
leaving Hubble and large
ground-based telescopes to
take up the slack. The space
telescope has shown Uranus,
which appeared as a bland,
bluish ball when Voyager 2
flew past in 1986, to be an
active world boasting bright
clouds of methane. And
in Neptune’s atmosphere,
Hubble has tracked massive
storms, some as big as Earth,
propelled by winds that aver-
age 900 mph (1,450 km/h).
Hubble also has tracked
storms on Jupiter and Saturn,
augmenting observations
made by orbiting spacecraft.
And it was the space telescope
that first detected evidence
that water vapor may beThe Hubble Space Telescope
floats free in low Earth orbit after
astronauts completed the fifth and
final servicing mission in May 2009.
With its new complement of
instruments, it was ready for the
21st century’s second decade. NASAHubble serves as a planetary
weather satellite, keeping tabs on
the atmospheres of our neighbors.
In June 2019, it snapped this image
of Jupiter showing the Great Red
Spot significantly smaller than it was
30 years before. NASA/ESA/A. SIMON (GSFC)/
M.H. WONG (UC, BERKELEY)In January 2002, the star at the
center of this image flared to became
one of our galaxy’s most luminous
suns. This view from October 2004
captures surrounding shells of dust
lit up by the eruption. NASA/ESA/THE HUBBLE
HERITAGE TEAM (STSCI/AURA)