Juno Mission Update 6/29/13

 

 

Mission Elapsed Time:
694 Days (1.91 years) 10 Hours 17 Minutes

Time to Earth Flyby Gravity Assist:
101 Days (3.4 months)16 Hours 45 Minutes

Time of Jupiter Arrival:
3 years 6 days 23 Hours 50 Minutes

 

As of June 21, Juno was approximately 50 million miles (80 million kilometers) from Earth. The one-way radio signal travel time between Earth and Juno is currently about 4.5 minutes. Juno is currently traveling at a velocity of about 19 miles (30 kilometers) per second relative to the sun, and increasing. Velocity relative to Earth is about 1.6 miles (2.6 kilometers) per second. Juno has now traveled 785 million miles (1.26 billion kilometers) since launch.  The Juno spacecraft is in excellent health and is operating nominally as it cruises toward its Oct. 9 Earth flyby gravity assist maneuver.

 

Juno’s Position and Course 6/29/13

Recent spacecraft significant events:

As of May 29, Juno has entered the phase of its mission titled "Inner Cruise 3," in which it has switched from its high-data-rate High Gain Antenna to its suite of lower data rate antennas. The magnetometer experiment remains powered on at low data rates, with all other science instruments currently powered off. Inner Cruise 3 lasts through Nov. 2013 and includes the Earth flyby.

 

Juno's Communications Antennas:  The Juno spacecraft has five antennas, including the largest and primary communication antenna, known as the high-gain antenna (HGA). Four other antennas can be used as backups, or when the main antenna is pointed away from Earth, for certain science operations and navigation maneuvers.

The solar-powered Juno spacecraft and its saucer-shaped high-gain antenna (or HGA) always point sunward, but while Juno is in the inner solar system, Earth’s position on the sky shifts dramatically. Earth’s movement means that Juno cannot always use its HGA and benefit from its high data rate connection. For this reason, the spacecraft has a suite of antennas that allow communications with Earth from other angles, but at the cost of lower data rates, resulting in a reduction in Juno’s ability to transmit science data during that time. Juno’s science instruments will be powered on again shortly before the Earth flyby, slated for Oct. 9.

 

Juno’s Main Engine Covered

Juno’s mission ops team performed a flush of the spacecraft’s main engine on May 1, firing the engine for a couple of seconds. The team does this maintenance activity about once per year to flush contaminants from the propellant lines that feed the main engine.

Juno Mission Update 4/29/13

Mission Elapsed Time:
633 Days (1.73 yrs.) 10 Hours 45 Minutes

Time to Earth Flyby Gravity Assist:
162 Days 16 Hours 11 Minutes

Time to Jupiter Arrival:
3 Years 67 Days 23 Hours 16 Minutes

 

As of April 29, Juno was approximately 52 million miles (84 million kilometers) from Earth. The one-way radio signal travel time between Earth and Juno is currently about 4.7 minutes. Juno is currently traveling at a velocity of about 15 miles (24 kilometers) per second relative to the sun. Velocity relative to Earth is about 6.8 miles (11 kilometers) per second.

 

Juno's Course and Position as of 4/29/13

 

Juno has now traveled 704 million miles since launch -- this is approximately 40 percent of the total distance the spacecraft travels between launch and orbit insertion at Jupiter. The Juno spacecraft is in excellent health and is operating nominally. Four instruments -- JEDI, MWR, Waves, and MAG -- are turned on.  Juno is currently headed back toward the inner solar system for a planned Earth flyby gravity assist maneuver on Oct. 9, 2013. The Juno mission operations team is continuing their planning activities in advance of this critical maneuver. The gravity assist will give the spacecraft the boost it needs to reach Jupiter, where it is slated to arrive in July 2016.
 

 

 

 

 

 

 

 

A high resolution image of Jupiter's clouds taken by NASA's Voyager 1 spacecraft as it flew past the planet in March 1979.

 

Artist's rendering of a Jupiter cloudscape.

 

Jupiter's clouds can swirl rapidly in raised high-pressure storm systems that circle the planet. The above pictured white ovals are located near the Great Red Spot, and have persisted on Jupiter since the 1930s. The Great Red Spot has persisted for at least 300 years. Currently, no one knows why ovals last as long as they do. White ovals are confined to circular belts around Jupiter, but can interact to cause nearby chaotic cloud regions.

 

Diagram showing theoretical conditions, temperatures, and pressures in Jupiter's interior.

 

Juno Mission Update 3/15/13

 

Mission Elapsed Time:

 

  588 Days (1.61 yrs.) 09 Hours 30 MinuteS

 

Time to Earth Flyby Gravity Assist:

207 Days (.57 yrs.) 17 Hours 27 Minutes

 

Time To Jupiter Arrival:

 

03 Years 111 Days 01 Hours 35 Minutes

 

As of March 8, Juno is approximately 92 million miles (147 million kilometers) from Earth, with a one-way radio signal travel time of 8.2 minutes. Juno is currently traveling at a velocity of 12.6 miles (20.2 kilometers) per second relative to the sun. Velocity relative to Earth is 13.9 miles (22.4 kilometers) per second.

 

Juno's Present Course and Position

The Juno spacecraft is in excellent health and is operating nominally. Four instruments -- JEDI, MAG, MWR and Waves -- are turned on.

 

'Hot Spots' Ride a Merry-Go-Round on Jupiter:

 

This false-color image from Cassini is a window deep into Jupiter's atmosphere. The arrow points to the dark hot spot. The bluish clouds to the right are in the upper troposphere, or perhaps higher still, in the stratosphere. The reddish gyre under the hot spot to the right and the large reddish plume at its lower left are in the lower troposphere.

In the swirling canopy of Jupiter's atmosphere, cloudless patches are so exceptional that the big ones get the special name "hot spots." Exactly how these clearings form and why they're only found near the planet’s equator have long been mysteries. Now, using images from NASA's Cassini spacecraft, scientists have found new evidence that hot spots in Jupiter's atmosphere are created by a Rossby wave, a pattern also seen in Earth's atmosphere and oceans. The team found the wave responsible for the hot spots glides up and down through layers of the atmosphere like a carousel horse on a merry-go-round.  Rossby waves are atmospheric waves (can be seen in the troughs and ridges of 500 hPa geopotential caused by midlatitude cyclones and anticyclones). The hPa or hecotoPascal is the SI derived unit of pressure, internal pressure, or stress in the atmosphere. It is a measure of force per unit area, defined as one newton per square meter. Rossby waves have been suggested as an important mechanism to account for the heating of Europa's ocean.

 

NASA postdoctoral fellow David Choi discusses his study of dark features in Jupiter's atmosphere called "hot spots," and their connection to large-scale atmospheric waves.

This is the first time anybody has closely tracked the shape of multiple hot spots over a period of time, which is the best way to appreciate the dynamic nature of these features," said the study's lead author, David Choi, a NASA Postdoctoral Fellow working at NASA's Goddard Space Flight Center in Greenbelt, Md.  The paper was published online in the April issue of the journal Icarus.  Choi and his colleagues made time-lapse movies from hundreds of observations taken by Cassini during its flyby of Jupiter in late 2000, when the spacecraft made its closest approach to the planet. The movies zoom in on a line of hot spots between one of Jupiter's dark belts and bright white zones, roughly 7 degrees north of the equator. Covering about two months (in Earth time), the study examines the daily and weekly changes in the sizes and shapes of the hot spots, each of which covers more area than North America, on average.

 

In this series of images from Cassini, a dark, rectangular hot spot (top) interacts with a line of vortices that approaches from on the upper-right side (second panel). The interaction distorts the shape of the hot spot (third panel), leaving it diminished (bottom).

Much of what scientists know about hot spots came from NASA's Galileo mission, which released an atmospheric probe that descended into a hot spot in 1995. This was the first, and so far only, in-situ investigation of Jupiter's atmosphere.  Galileo's probe data and a handful of orbiter images hinted at the complex winds swirling around and through these hot spots, raised questions about whether they fundamentally were waves, cyclones or something in between," said Ashwin Vasavada, a paper co-author who is based at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and who was a member of the Cassini imaging team during the Jupiter flyby. "Cassini's fantastic movies now show the entire life cycle and evolution of hot spots in great detail.

 

Infrared image of Jupiter taken by the ESO's Very Large Telescope.

Because hot spots are breaks in the clouds, they provide windows into a normally unseen layer of Jupiter's atmosphere, possibly all the way down to the level where water clouds can form. In pictures, hot spots appear shadowy, but because the deeper layers are warmer, hot spots are very bright at the infrared wavelengths where heat is sensed; in fact, this is how they got their name.  One hypothesis is that hot spots occur when big drafts of air sink in the atmosphere and get heated or dried out in the process. But the surprising regularity of hot spots has led some researchers to suspect there is an atmospheric wave involved. Typically, eight to 10 hot spots line up, roughly evenly spaced, with dense white plumes of cloud in between. This pattern could be explained by a wave that pushes cold air down, breaking up any clouds, and then carries warm air up, causing the heavy cloud cover seen in the plumes. Computer modeling has strengthened this line of reasoning.

From the Cassini movies, the researchers mapped the winds in and around each hot spot and plume, and examined interactions with vortices that pass by, in addition to wind gyres, or spiraling vortices, that merge with the hot spots. To separate these motions from the jet stream in which the hot spots reside, the scientists also tracked the movements of small "scooter" clouds, similar to cirrus clouds on Earth. This provided what may be the first direct measurement of the true wind speed of the jet stream, which was clocked at about 300 to 450 mph (500 to 720 kilometers per hour) -- much faster than anyone previously thought. The hot spots amble at the more leisurely pace of about 225 mph (362 kilometers per hour).  By teasing out these individual movements, the researchers saw that the motions of the hot spots fit the pattern of a Rossby wave in the atmosphere. On Earth, Rossby waves play a major role in weather. For example, when a blast of frigid Arctic air suddenly dips down and freezes Florida's crops, a Rossby wave is interacting with the polar jet stream and sending it off its typical course. The wave travels around our planet but periodically wanders north and south as it goes.

Juno Mission Update 1/21/13

 

Elapsed Mission Time:
534 Days (1.46 yrs.) 12  Hours 56 Minutes

Time Until Earth Flyby Gravity Assist:
261 Days (.72 yrs.) 02 Hours 01 Minutes

 

As of Jan. 20, Juno was approximately 160 million miles (257 million kilometers) from Earth, with a one-way radio signal travel time of approximately 14 minutes. Juno is currently traveling at a velocity of 11 miles (18 kilometers) per second relative to the sun. Velocity relative to Earth is 20 miles (32 kilometers) per second.

 

Juno's Course and Position 1/20/13

 

The Juno spacecraft is in excellent health and is operating nominally. Four instruments -- JEDI, MWR, Waves, and MAG -- are turned on.  Juno is currently headed back toward the inner solar system for a planned Earth flyby gravity assist maneuver on Oct. 9, 2013. The gravity assist will give the spacecraft the boost it needs to reach Jupiter, where it is slated to arrive in July 2016.

 

 

Juno Mission Overview Update:

Juno Mission Update 12/12/12

 

 

Mission Elapsed Time:
495 Days (1.36 yrs.) 09 Hours 39 Minutes

Time of Earth Flyby Gravity Assist:
300 Days (.82 yrs.) 06 Hours 17 Minutes

Juno's Time of Arrival:
1300 Days ( 3.55 yrs.) 00 Hours 18 Minutes

 

Juno is currently headed back toward the inner solar system for a planned Earth flyby gravity assist maneuver on Oct. 9, 2013. The gravity assist will give the spacecraft the boost it needs to reach Jupiter, where it is slated to arrive in July 2016. 

 

Juno's Current Position 12/12/12

As of Dec. 10, Juno was approximately 216 million miles (347 million kilometers) from Earth, with a one-way radio signal travel time of approximately 19 minutes. The spacecraft has now traveled 561 million miles (903 million kilometers, or 6.03 AU) since launch. Juno is currently traveling at a velocity of 10 miles (16 kilometers) per second relative to the sun. Velocity relative to Earth is 23 miles (37 kilometers) per second.  The Juno spacecraft is in excellent health and is operating nominally. Four instruments -- JEDI, MWR, Waves, and MAG -- are turned on.

Now for a little past history about the first mission to Jupiter Galileo: 

At Kennedy Space Center, Oct. 18, 1989:   A roar shakes the ground as Space Shuttle Atlantis climbs into the sky. The Galileo spacecraft rides in the payload bay, ready to begin a long journey into the realm of the outer planets. Its mission is to study Jupiter and its moons in more detail than any previous spacecraft.

 

Galileo

The spacecraft is named in honor of the first modern astronomer --- Galileo Galilei. He made the first observations of the heavens using a telescope in 1610.  What compels us to explore Jupiter? The giant colorful planet holds clues to help us understand how the Sun and planets formed more than 4.5 billion years ago. One of Jupiter's moons has active volcanoes and others have strange icy terrain. How does these strange worlds compare with Earth?

 

Galileo Spacecraft Arriving at Jupiter

 

Galileo arrived at Jupiter in December 1995.  As fascinating data poured in from the orbiting spacecraft and its atmospheric probe, we knew it was just the beginning.   Galileo changed the way we look at our solar system. The spacecraft was the first to fly past an asteroid and the first to discover a moon of an asteroid. It provided the only direct observations of a comet colliding with a planet.

 

Galileo Ganymede

Galileo was the first to measure Jupiter's atmosphere with a descent probe and the first to conduct long-term observations of the Jovian system from orbit. It found evidence of subsurface saltwater on Europa, Ganymede and Callisto and revealed the intensity of volcanic activity on Io.

 

Galileo Callisto

The history of Jupiter exploration began with the invention of the telescope in the early seventeenth century. The first telescopes were not very powerful, and the views were not very sharp. But over the next three hundred years, the telescope was continually improved, and became our primary tool for observing the stars and planets.

 

                                      Galileo Io

Human explorers have taken dangerous journeys to the far corners of Earth and even to the Moon. But to explore the outer reaches of the solar system, we send spacecraft equipped with cameras and scientific instruments. In a way, we send extensions of ourselves on these missions.

Galileo moons  Thebe, Amalthea and Metis

The cameras becomes our "eyes" to view the other planets up close. Special instruments "see" in infrared, ultraviolet, and other wavelengths of light --- revealing what is invisible to our eyes.  Today, we have very large and powerful telescopes. The Hubble Space Telescope, orbiting above Earth's atmosphere, can see far into space. Yet, the planets of our Solar System still hold many mysteries to investigate. NASA's first planetary missions were "fly-bys." The spacecraft simply zoomed by a planet taking pictures or gathering data, and then continued on --- out into deep space.

 

Great Red Spot Collage:

 

 

But orbiting a planet gives us a chance to learn a great deal more about it. The Viking orbiters at Mars and the Magellan orbiter at Venus studied planets in the inner solar system. Galileo was the first spacecraft to orbit Jupiter in the outer solar system.

 

 

Galileo plunged into Jupiter's crushing atmosphere on Sept. 21, 2003.  The spacecraft was purposely put on a collision course with Jupiter because the onboard propellant was nearly depleted and to eliminate any chance of an unwanted impact between the spacecraft and Jupiter's moon Europa, which Galileo discovered and is likely to have a subsurface ocean.  The Galileo spacecraft's 14-year odyssey came to an end on Sunday, Sept. 21, when the spacecraft passed into Jupiter's shadow then disintegrated in the planet's dense atmosphere at 11:57 a.m. (PDT). The Deep Space Network tracking station in Goldstone, Calif., received the last signal at 12:43:14 (PDT). The delay is due to the time it takes the signal to travel to Earth.

Galileo is directed to crash into Jupiter and burns up in the atmosphere.

Juno Mission Update 10/17/12

 

 

Mission Elapsed Time:  439 Days (1.20 yrs.) 11 Hours 25 Minutes

Time of Arrival:  1355 Days ( 3.71 yrs.) 22 Hours 35 Minutes

 

Juno is approximately 282 million miles (452 million kilometers) from Earth, with a one-way radio signal travel time of approximately 25 minutes. The spacecraft has now traveled 512 million miles (824 million kilometers) since launch, which is nearly 27 percent of its total cruise distance to Jupiter. Juno is currently traveling at a velocity of 33,600 miles (54,000 kilometers) per hour relative to the sun. Velocity relative to Earth is 94,900 miles (152,600 kilometers) per hour.

 

Juno’s Current Position and Course

The Juno spacecraft is in excellent health and is operating nominally. Four instruments -- JEDI, MWR, Waves, and the magnetometer experiment -- are turned on. Juno’s mission operations team is currently focused on periodic maintenance activities for the science instruments, turning on each one for a few days at a time to monitor its health and performance.  Juno is currently headed back toward the inner solar system for a planned Earth flyby gravity assist maneuver on Oct. 9, 2013. The spacecraft completed a trajectory control maneuver (TCM-5) using its reaction control thrusters on Oct. 3, for the fifth time further refining its path toward Earth.  Juno was not designed to study the Jovian moons, but may take a few distant images.  More detailed info in the future on this subject.

 

New results from NASA's Wide-field Infrared Explorer, or WISE, reveal that the Jovian Trojans -- asteroids that lap the sun in the same orbit as Jupiter -- are uniformly dark with a hint of burgundy color, and have matte surfaces that reflect little sunlight.   The color could indicate heavy concentration of the element Iron.

Scientists using data from NASA's Wide-field Infrared Survey Explorer, or WISE, have uncovered new clues in the ongoing mystery of the Jovian Trojans -- asteroids that orbit the sun on the same path as Jupiter. Like racehorses, the asteroids travel in packs, with one group leading the way in front of the gas giant, and a second group trailing behind.  The observations are the first to get a detailed look at the Trojans' colors: both the leading and trailing packs are made up of predominantly dark, reddish rocks with a matte, non-reflecting surface. What's more, the data verify the previous suspicion that the leading pack of Trojans outnumbers the trailing bunch.
The new results offer clues in the puzzle of the asteroids' origins. Where did the Trojans come from? What are they made of? WISE has shown that the two packs of rocks are strikingly similar and do not harbor any "out-of-towners," or interlopers, from other parts of the solar system. The Trojans do not resemble the asteroids from the main belt between Mars and Jupiter, nor the Kuiper belt family of objects from the icier, outer regions near Pluto.
"Jupiter and Saturn are in calm, stable orbits today, but in their past, they rumbled around and disrupted any asteroids that were in orbit with these planets," said Tommy Grav, a WISE scientist from the Planetary Science Institute in Tucson, Ariz. "Later, Jupiter re-captured the Trojan asteroids, but we don't know where they came from. Our results suggest they may have been captured locally. If so, that's exciting because it means these asteroids could be made of primordial material from this particular part of the solar system, something we don't know much about." Grav is a member of the NEOWISE team, the asteroid-hunting portion of the WISE mission.

Astronomer Max Wolf

The first Trojan was discovered on Feb. 22, 1906, by German astronomer Max Wolf, who found the celestial object leading ahead of Jupiter. Christened "Achilles" by the astronomer, the roughly 81-mile-wide (130-kilometer-wide) chunk of space rock was the first of many asteroids detected to be traveling in front of the gas giant. Later, asteroids were also found trailing behind Jupiter. The asteroids were collectively named Trojans after a legend, in which Greek soldiers hid inside in a giant horse statue to launch a surprise attack on the Trojan people of the city of Troy.

 

 

NASA's Wide-field Infrared Survey Explorer, or WISE, spacecraft is situated on a work stand. At left on the spacecraft is the fixed panel solar array. In front, the square is the HGA Slotted Array (Ku-Band).

Juno Mission Update 9/21/12

 

Elapsed Mission Time:  413 Days (1.23 yrs.) 04 Hours 57 Minutes

Time of Arrival:  1387 Days (3.8 yrs.) 08 Hours 02 Minutes

 

As of Sept. 19, Juno was approximately 294 million miles (473 million kilometers) from Earth, with a one-way radio signal travel time of approximately 26.4 minutes. The spacecraft has now traveled 495 million miles (797 million kilometers) since launch. Juno is currently traveling at a velocity of 33,200 miles (53,400 kilometers) per hour relative to the sun. Velocity relative to Earth is 97,000 miles (156,100 kilometers) per hour. The spacecraft is in excellent health and is operating nominally. Three instruments -- MWR, Waves, and the magnetometer experiment -- are turned on and collecting data.

 

 

Juno Firing It’s Main Engine

 

Juno’s second deep space maneuver (or DSM) was performed on Sept. 14; the first maneuver was successfully completed on Aug. 30. Following these two large main engine burns, the spacecraft was put back into cruise configuration and is now headed back toward the inner solar system for a planned Earth flyby gravity assist maneuver which will occur on Oct. 9, 2013. The two deep space engine burns were back-to-back successes !

 

Juno's Current Course and Position

NASA could have spent fuel for thrusters or use power for reaction wheels w/ moving parts. But Juno being a "simple spinner" spacecraft has its advantages. Spinning makes the spacecraft stable, like a gyroscope. Simpler than using reaction wheels, and no moving parts to wear out.