way. The Earth flyby resulted in an
increase of 16,330 miles per hour to
the spacecraft’s velocity. The probe
then shot out of Earth’s gravity heading on a direct path to Jupiter.
Getting to Jupiter is no easy task,
getting into orbit is even harder. After
nearly five years of flight and over 1.7
billion miles travelled, the spacecraft
would be approaching Jupiter at an
astonishing speed. Juno would have
the title of the fastest spacecraft ever
with a top speed of over 165,000
mph and would be approaching
Jupiter at over 150,000 mph as the
giant planet’s gravity pulled it in.
The JunoCam consists of a camera head and an electronics box, which is housed inside the spacecraft’s protective radiation vault). In the inset image, JunoCam is shown mounted on the orbiter. Credits: NASA / JPL-Caltech
instruments, JunoCam’s primary
purpose is for public engagement.
Images taken by the JunoCam will
be available to the public via the
Juno mission website. Images will be
taken mainly while the spacecraft is
making its close flybys of the planet,
about 3,100 miles above the cloud
tops.
Remember that Juno is spinning
at two revolutions per minute at that
point, so images would be blurred
if JunoCam took a full image like
you do with your DSLR. To solve this
issue, JunoCam takes thin strips of
an image at the same rate that the
spacecraft is spinning, then stitches
them together to complete a full image.
The camera is mounted on the
outside of Juno exposing it to the
high-energy particles that surround
Jupiter, therefore eventually it will be
so damaged by the particles that
the team will just shut it down for
the remainder of the mission. They
expect it to last at least seven orbits,
plenty of time for some great imagery to be returned to Earth.
Just a few days after Juno entered
orbit on July 5, Junocam was already
operating. The first high resolution images won’t be taken until August 27,
however it did send down a grainier
image indicating that Juno survived
60
60
its first pass through Jupiter’s extreme
radiation.
The JunoCam team also has a
website where you can talk about
the images. You can also vote on
points of interest for JunoCam to
photograph on upcoming orbit(s).
You can also download and process images and then upload them
back to the website and see other
people’s processed images. Go to
https://www.missionjuno.swri.edu/
junocam to explore JunoCam community on your own.
Juno’s long journey to the gas giant began over five years before its
arrival in the Jovian system. Launching on August 5, 2011 on top of an
United Launch Alliance Atlas V rocket from cape Canaveral Air Station.
The Atlas V is a powerful rocket on its
own, but to get Juno to Jupiter, five
Solid Rocket Boosters were added to
the launch vehicle to provide more
thrust to lift the 7,992 pound (3,625
KG) probe away from the Earth.
The trajectory of the spacecraft initially placed it in a heliocentric orbit
that took it out past the orbit of Mars
before maneuvering to a gravity assist flyby of Earth over two years after
launch. On October 9, 2013 Juno
skimmed passed the Earth, zipping
past us just 310 miles above the surface while gaining speed along the
If the burn to slow it down to enter orbit failed, it would just scream
past Jupiter and keep right on going.
However the 30 minute long orbit entry burn did go off as scheduled, and
while it only slowed the spacecraft
down 1,212 mph, that was all that
was needed to put Juno in what is
known as its capture orbit.
The first two orbits, called ‘Capture
Orbit.’ will each take 53.5 days to
complete and are used primarily as
a way to save fuel as the gravity of
Jupiter continues to slow the spacecraft down during these orbits allowing it to get into its planned 14 day
orbit of the planet.
During this first orbit the science
team will check out all the instruments and begin taking some science measurements to ensure all is
functioning well with the spacecraft
in the Jupiter environment. The Capture Orbit phase of the mission will
not complete until October 14.
Five days after the Capture Orbit
phase of the mission comes what
is called the Period Reduction Maneuver. This involves another burn
of the engine designed to bring the
spacecraft’s 53.5 day orbit around
Jupiter down to just 14 days. This time
the burn will last for 22 minutes and
is the last planned large firing of the
spacecraft’s main engine.
Due to some unique conditions
associated with the maneuver, the
spacecraft will have three active science instruments during this phase
of this mission. The spacecraft will be
at a unique rate of spin and altitude
during this phase which should allow
the Microwave Radiometer to scan
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