Wednesday, December 12, 2012

Juno Mission Update 12/12/12

 

Juno firing rockets

 

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. 

 

Junos position12-12-12

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

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 arrival at Jupiter

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 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

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

                                      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

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:

 

Jupiter 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 eurropa surface features

 

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_End burning up in Jupiter's atmos.

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

Wednesday, October 17, 2012

Juno Mission Update 10/17/12

 

Juno fires its main engine

 


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 10-17-12

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.

 

Jupiter's trojan asteroids

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.

JUno german astronomer Max Wolf

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.

 

JUno-Wise spacecraft

 

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).

Friday, September 21, 2012

Juno Mission Update 9/21/12

 

Juno firing main rockets

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 fires its main engine

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 9-21

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.

Friday, August 31, 2012

Juno Mission Update 8/31/12

 

Juno artist concept

 

Mission Elapsed Time:
392 days (1.07 yrs.) 04 Hours 47 Minutes

 

Time of Arrival:
1463 Days (4.01 yrs.) 05 Hours 14 Minutes

 

As of Aug. 29, Juno was approximately 302 million miles (486 million kilometers) from Earth, with a one-way radio signal travel time of approximately 27.1 minutes. The spacecraft has now traveled 478 million miles (769 million kilometers) since launch, or approximately 25 percent of the 20.49 AU distance that the spacecraft covers between launch and arrival at Jupiter.

 

Juno Communications

Juno is currently traveling at a velocity of 34,000 miles (54,700 kilometers) per hour relative to the sun. Velocity relative to Earth is 99,200 miles (159,600 kilometers) per hour. The spacecraft is in excellent health and is operating nominally. All instruments except the Advanced Stellar Compass (part of the magnetometer experiment) are turned off, as planned, in preparation for the deep space maneuvers.

 

Juno position and course

View of Juno’s position on Aug. 30 from Eyes on the Solar System.

Jupiter-Bound Juno Changes its Orbit

Earlier today, navigators and mission controllers for NASA's Juno mission to Jupiter watched their computer screens as their spacecraft successfully performed its first deep-space maneuver. This first firing of Juno's main engine is one of two planned to refine the spacecraft's trajectory, setting the stage for a gravity assist from a flyby of Earth on Oct 9, 2013. Juno will arrive at Jupiter on July 4, 2016.
The deep-space maneuver began at 6:57 p.m. EDT (3:57 p.m. PDT) today, when the Leros-1b main engine was fired for 29 minutes 39 seconds. Based on telemetry, the Juno project team believes the burn was accurate, changing the spacecraft's velocity by about 770 mph (344 meters a second) while consuming about 829 pounds (376 kilograms) of fuel.

Juno firing rockets

Artist’s concept depicts NASA’s Juno spacecraft during a burn of its main engine.


"This first and successful main engine burn is the payoff for a lot of hard work and planning by the operations team," said Juno Project Manager Rick Nybakken of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We started detailed preparations for this maneuver earlier this year, and over the last five months we've been characterizing and configuring the spacecraft, primarily in the propulsion and thermal systems. Over the last two weeks, we have carried out planned events almost every day, including heating tanks, configuring subsystems, uplinking new sequences, turning off the instruments and increasing the spacecraft's spin rate. There is a lot that goes into a main engine .
The burn occurred when Juno was more than 300 million miles (483 million kilometers) away from Earth. A second deep space maneuver, of comparable duration and velocity change, is planned for Sept. 4. Together, they will place Juno on course for its Earth flyby, which will occur as the spacecraft is completing one elliptical orbit around the sun. The Earth flyby will boost Juno's velocity by 16,330 mph (about 7.3 kilometers per second), placing the spacecraft on its final flight path for Jupiter. The closest approach to Earth, on Oct. 9, 2013, will occur when Juno is at an altitude of about 310 miles (500 kilometers).

simulation of Junos deep space maneuver

Simulated view of Juno during its first deep space maneuver

One of Juno’s deep space maneuvers (or DSMs), took place on Aug. 30 and the next maneuver on Sept. 4. During these maneuvers the spacecraft will fire its main engine for 30 minutes. The maneuvers refine the spacecraft’s trajectory and set up the Earth flyby gravity assist maneuver in Oct. of next year. Nominal start time (spacecraft event time) for the burns is 22:30 UTC (3:30pm US Pacific time) on both dates; Earth received time for the signals from the spacecraft is 27 minutes later.

After the Earth flyby it will be another 1.4 billion miles and four years to go to get to Jupiter.  Scott Bolton, Juno's principal investigator from the Southwest Research Institute in San Antonio stated, "The team will be busy during that whole time, collecting science data on the way out to Jupiter and getting ready for our prime mission at Jupiter, which is focused on learning the history of how our solar system was formed. We need to go to Jupiter to learn this history because Jupiter is the largest of the planets, and it was formed by grabbing most of the material left over from the sun's formation."  Probably much of what was to go Mars was gobbled up by Jupiter- hence Mar's size. Earth and the other planets are really made from the leftovers of the leftovers, planetesimals and asteroids from the early Solar System. The asteroid belt would have been more heavily populated than now. So if we want to learn about the history of the elements that made Earth and life, we need to  understand what happened when was Jupiter formed .

 

asteroid belt early

The Early Asteroid Belt

Wednesday, August 8, 2012

Juno Mission Update 8/8/12

 

JUno spacecraft 2

 

Mission Elapsed Time:

369 (1.01 yrs.) Days 08 Hours 50 Minutes

Time of Arrival:

1426 ( 3.91 yrs.) Days 01 Hours 02 Minutes

 

JPL issued a news note  with that most dreaded of press release titles: "Mission Status Report," which some dread because it's usually a euphemism for "something bad has happened to one of our spacecraft." But this time it contains nothing but good news. It briefly notes that the Jupiter-bound Juno spacecraft has successfully completed some of the first of  the twelve trajectory correction maneuvers it'll perform between the launch last year and Jupiter arrival in 2016. Its next maneuver will take place in August of this year (this month). NASA's Juno spacecraft is outbound from the Sun, heading way beyond Mars' orbit before heading sunward again ending in a  Earth flyby in August 2013  that will send it on to a July 2016 Jupiter arrival.

 

Juno position 8-8-12

Juno’s Present Position and Course 8/8/12

Juno's science objectives are to:


1. Determine how much water is in Jupiter's atmosphere, to help identify which planet formation theory is correct .

2. Look deep into Jupiter's atmosphere to measure composition, temperature, cloud motions and other properties

3. Map Jupiter's magnetic and gravity fields, revealing the planet's deep structure

4. Explore and study Jupiter's magnetosphere near the planet's poles, especially the auroras, providing new insights about how the planet's enormous magnetic force field affects its atmosphere.

 

Juno south pole

A simulated view of Jupiter's South Pole illustrates Juno's unique perspective which will allow Juno's camera to image Jupiter's clouds from a vantage point never seen before.

Juno's investigations focus on four themes:

1. Origin – Jupiter's solid core and abundance of heavy metals in the atmosphere make it an ideal model to understand the origin of giant planets. Juno will measure global abundances of oxygen and nitrogen by mapping the gravitational field and using microwave observations of water and ammonia.

2. Interior – Juno will map Jupiter's gravitation and magnetic fields, revealing the interior structure, the origin of the magnetic field, the mass of its core, the nature of deep convection, and the abundance of water.

 

The Interior of Jupiter

 

3. Atmosphere – Jupiter has the most massive atmosphere of all the planets. By mapping variations in atmospheric composition, temperature, cloud opacity and dynamics to depths greater than 100 bars at all latitudes, Juno will determine the global structure and dynamics of Jupiter’s atmosphere below the cloud tops for the first time.

4. Magnetosphere–Jupiter’s powerful magnetospheric dynamics create the brightest aurora in our solar system. Juno will measure the distribution of the charged particles, their associated fields, and the concurrent UV emissions of the planet’s polar magnetosphere, greatly improving our understanding of this remarkable phenomena.

 

Juno Jupiter aurora

Auroras at Jupiter's North and South Poles

Jupiter’s Auroras

Wednesday, June 27, 2012

Juno 3 Mission Update 6/27/12

 

Mission Elapsed Time:  327 days (.90 yrs.) 10 hours 25 minutes

Time of Arrival:  1467 days (4.01 yrs.) 23 hours 37 minutes

 

JunoAboveClouds

 

As of June 20, Juno was approximately 287 million miles (462 million kilometers) from Earth, with a one-way radio signal travel time of approximately 25.7 minutes. The spacecraft has traveled 419 million miles (674 million kilometers) since launch, which represents approximately 22 percent of the total distance Juno will cover between launch and arrival at Jupiter. That distance is 20.49 astronomical units (1.9 billion miles, or 3.1 billion kilometers), or nearly five times greater than the separation between the orbits of Earth and Jupiter.

 

Juno on 6-27-12

Juno’s present Course and position as of this post

Juno is currently traveling at a velocity of 36,100 miles (58,100 kilometers) per hour relative to the sun. Velocity relative to Earth is 99,100 miles (159,400 kilometers) per hour. The spacecraft is in excellent health and is operating nominally. Four instruments are turned on: the Magnetometer experiment (FGM & ASC), JEDI, MWR and Waves:

 

Magnetometry 101
Most recent spacecraft significant events:

On June 20, flight controllers commanded the spacecraft to test opening and closing the external cover that protects its main engine, and to fill the propellant lines that supply the engine with liquid oxygen and hydrazine, in preparation for its upcoming deep space maneuvers, slated for Aug. 30 and Sept. 4.


 

Mission Timeline:

1. Launch - August 5, 2011
2. Deep Space Maneuvers - August/September 2012
3. Earth flyby gravity assist - October 2013
4. Jupiter arrival - July 2016
5. Spacecraft will orbit Jupiter for about one year (33 orbits)
6,  End of mission (deorbit into Jupiter) - October 2017

Juno will take an orbit that will give it an Earth gravity assist once it goes around the sun and heads back towards Jupiter.  This is what is called the "sling-shot" effect and will save on the spacecraft's use of fuel:

 

Friday, May 25, 2012

Juno Mission 2:

 

Juno Mission Update 5/25/12

 

Mission Elapsed Time: 294 days 09 hours 25 minutes

 

Time of Arrival: 1500 days 23 hours 11 minutes

 

JunoAboveClouds

 

Launched on Aug. 5, 2011, the solar-powered Juno spacecraft is 294 days and 380 million miles (612 million kilometers) into its five-year, 1,905-million-mile (3,065-million-kilometer) journey to Jupiter. Once there, the spacecraft will orbit the planet's poles 33 times and use its nine instruments to image and probe beneath the gas giant's obscuring cloud cover to learn more about Jupiter's origins, structure, atmosphere and magnetosphere, and look for a potential solid planetary core.

Juno's pictue of big dipper

One of those instruments, JunoCam, is tasked with taking close-ups of the gas giant's atmosphere. But, with four-and-a-half years to go before photons of light from Jupiter first fill its CCD (charge-coupled device), and a desire to certify the camera in flight, Juno's mission planners took a page from their childhood and on March 21, aimed their camera at a familiar celestial landmark the Big Dipper.

Juno's name comes from Greek and Roman mythology. The god Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.

Juno's photo of Earth and moon

On its way to the biggest planet in the solar system -- Jupiter, NASA's Juno spacecraft took time to capture its home planet and its natural satellite -- the moon.

"This is a remarkable sight people get to see all too rarely," said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. "This view of our planet shows how Earth looks from the outside, illustrating a special perspective of our role and place in the universe. We see a humbling yet beautiful view of ourselves."  The image was taken by the spacecraft’s camera, JunoCam, on Aug. 26 when the spacecraft was about 6 million miles (9.66 million kilometers) away. The image was taken as part of the mission team’s checkout of the Juno spacecraft.

The JunoCam:
The JunoCam will capture color pictures of Jupiter's cloud tops in visible light. The JunoCam will provide a wide-angle view of Jupiter's atmosphere and poles. JunoCam is designed as an outreach full-color camera to engage the public. The public will be involved in developing the images from raw data and even helping to design which areas of Jupiter should be imaged.

Junocam

The JunoCam

The JunoCam camera head has a lens with a 58-degree cross-scan field of view. It acquires images by sweeping out that field while the spacecraft spins to cover an along-scan field of view of 360 degrees. Lines containing dark sky are subsequently compressed to an insignificant data volume. It takes images mainly when Juno is very close to Jupiter, with a maximum resolution of up to 1 to 2 miles (2 to 3 kilometers) per pixel. The wide-angle camera will provide new views of Jupiter's atmosphere. JunoCam's hardware is based on a descent camera that was developed for NASA's Mars Science Laboratory rover. Some of its software was originally developed for NASA's Mars Odyssey and Mars Reconnaissance Orbiter spacecraft. JunoCam is provided by Malin Space Science Systems, San Diego, Calif.

juno today

This is Juno's present course and position

Juno covered the distance from Earth to the moon (about 250,000 miles or 402,000 kilometers) in less than one day's time. It will take the spacecraft another five years and 1,740 million miles (2,800 million kilometers) to complete the journey to Jupiter. The spacecraft will orbit the planet's poles 33 times and use its eight science instruments to probe beneath the gas giant's obscuring cloud cover to learn more about its origins, structure, atmosphere and magnetosphere, and look for a potential solid planetary core.  After a year of that work it will be allowed to crash into Jupiter's surface to learn more about the planet similar to the LRO/LACROSS mission on the moon.  Except Juno will be the surveyor and excavator on Jupiter.
The Juno spacecraft is in excellent health and is operating nominally. Four instruments are turned on: the Magnetometer experiment (FGM & ASC), JEDI, MWR and Waves
.

Most recent spacecraft significant events:

During the week of April 5-11, the Juno mission operations team completed a demonstration test of the propulsion tank heating sequence that will be used prior to the upcoming main engine firings, scheduled for Aug. 30 and Sept. 4. These engine burns are referred to as Juno’s “deep space maneuvers,” and they serve to keep the spacecraft on course for its Oct. 2013 gravity assist flyby of Earth. The recent test serves to validate plans for warming the tanks and the propellant they contain to the temperatures required for the deep space maneuvers.

Propulsion System:

Juno's main engine covered

Technicians prepare NASA's Juno spacecraft for a functional test of its main engine cover. The spacecraft rests upon a dolly, which has tall legs to provide the necessary ground clearance for the engine cover to open. The cover will remain closed for most of Juno's mission, but must open for two main engine burns in 2012 that set up an Earth flyby gravity assist maneuver, and then in 2016 for the Jupiter orbit insertion burn and period reduction maneuver.

Juno's fuel tanks

An exposed, side view of NASA's Juno spacecraft during its assembly features three of the spacecraft's spherical propellant tanks. Nearby, technicians install components that will aid with the spacecraft's guidance, navigation and control.

For weight savings and redundancy, Juno uses a dual mode propulsion subsystem, with a bi-propellant main engine and mono-propellant reaction control system thrusters. The Leros-1b main engine is a 645-Newton bi-propellant thruster using hydrazine-nitrogen tetroxide. Its engine bell is enclosed in a micrometeoroid shield that opens for engine burns. The engine is fixed to the spacecraft body firing aft and is used for major maneuvers and flushing burns. The 12 reaction control system thrusters are mounted on four rocket engine modules. They allow translation and rotation about three axes. They are also used for most trajectory correction maneuvers.

Juno a Rotating Spacecraft:

For Juno, like NASA's earlier Pioneer spacecraft, spinning makes the spacecraft's pointing extremely stable and easy to control. Just after launch, and before its solar arrays are deployed, Juno will be spun-up by rocket motors on its still-attached second-stage rocket booster. Juno's planned spin rate varies during the mission: 1 RPM for cruise, 2 RPM for science operations and 5 RPM for main engine maneuvers.

Juno is a mission of discovery and exploration that will conduct an in-depth study of Jupiter, the most massive planet in our solar system. Peering through the clouds deep into Jupiter's atmosphere, the mission will reveal fundamental processes of the formation and early evolution of our solar system. Juno's goal is to understand the origin and evolution of the gas giant planet, which will pave the way to a better understanding of our solar system and other planetary systems being discovered around other stars.

Scott_Bolton


The Juno mission is managed for NASA by the Jet Propulsion Laboratory in Pasadena, CA. The Principal Investigator is Dr. Scott Bolton of Southwest Research Institute, San Antonio, TX. The Juno spacecraft was built by Lockheed Martin Space Systems, Denver, CO.

Thursday, April 26, 2012

The Juno Mission

 

The Juno Mission Report 1
4/26/12

 

Juno lauch atlas

Juno Launch From Cape Canaveral

Spacecraft: Juno

Launch Vehicle: United Launch Alliance Atlas V-551

Launch Site: Launch Complex 41, Cape Canaveral Air Force Station

Launch Date: Aug. 5, 2011

Launch Time: 12:25 p.m. EDT

Elapsed Time: 263 days

Juno artist concept

Juno Spacecraft Art

A Five-Year Journey:

Juno’s trip to Jupiter will take about five years. Though the journey may seem long, this flight plan allows the mission to use Earth’s gravity to speed the craft on its way. The spacecraft first loops around the inner solar system and then swings past Earth two years after launch to get a boost that will propel it onward to its destination. In July 2016, Juno will fire its main engine and slip into orbit around the giant planet to begin its scientific mission.


A Solar-Powered, Spinning Spacecraft:

juno solar array

Actual size of Solar Array (3)

Jupiter’s orbit is five times farther from the sun than Earth’s location, so the giant planet receives about 25 times less sunlight than Earth. Juno will be the first solar-powered spacecraft designed to operate at such a great distance from the sun, and its solar panels must be quite large to generate sufficient power there. To meet this challenge, three solar panels extend outward from Juno’s hexagonal body, giving the spacecraft an overall span of 20 meters (66 feet).

Objectives:

Juno will improve our understanding of the solar system’s beginnings by revealing the origin and evolution of Jupiter.


Specifically, Juno will do the following activities:


1. Determine how much water is in Jupiter’s atmosphere, which helps determine which planet formation theory is correct (or if new theories are needed)
2. Look deep into Jupiter’s atmosphere to measure composition, temperature, cloud motions and other properties
3. Map Jupiter’s magnetic and gravity fields, revealing the planet’s deep structure
4. Explore and study Jupiter’s magnetosphere near the planet’s poles, especially the auroras – Jupiter’s northern and southern lights – providing new insights about how the planet’s enormous magnetic force field affects its atmosphere.

The Giant Planet Story is the Story of the Solar System :

RingsofJupiter

The Rings of Jupiter

Juno’s principal goal is to understand the origin and evolution of Jupiter. Underneath its dense cloud cover, Jupiter safeguards secrets to the fundamental processes and conditions that governed our solar system during its formation. As a primary example of a giant planet, Jupiter can also provide critical knowledge for understanding the planetary systems being discovered around other stars.  With its suite of science instruments, Juno will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras.  Juno will let us take a giant step forward in our understanding of how giant planets form and the role these titans played in putting together the rest of the solar system.

Jupiter’s Origins and Interior:

Theories about solar system formation all begin with the collapse of a giant cloud of gas and dust, or nebula, most of which formed the infant sun. Like the sun, Jupiter is mostly hydrogen and helium, so it must have formed early, capturing most of the material left after our star came to be. How this happened, however, is unclear. Did a massive planetary core form first and gravitationally capture all that gas, or did an unstable region collapse inside the nebula, triggering the planet’s formation? Differences between these scenarios are profound.

Atmosphere:

How deep Jupiter's colorful zones, belts, and other features penetrate is one of the most outstanding fundamental questions about the giant planet. Juno will determine the global structure and motions of the planet’s atmosphere below the cloud tops for the first time, mapping variations in the atmosphere’s composition, temperature, clouds and patterns of movement down to unprecedented depths.

Magnetosphere:

Deep in Jupiter's atmosphere, under great pressure, hydrogen gas is squeezed into a fluid known as metallic hydrogen. At these great depths, the hydrogen acts like an electrically conducting metal which is believed to be the source of the planet's intense magnetic field. This powerful magnetic environment creates the brightest auroras in our solar system, as charged particles precipitate down into the planet’s atmosphere. Juno will directly sample the charged particles and magnetic fields near Jupiter’s poles for the first time, while simultaneously observing the auroras in ultraviolet light produced by the extraordinary amounts of energy crashing into the polar regions.

Spacecraft & Instruments:

Microsoft PowerPoint - Juno Payload Poster #488457.ppt [Compatibility Mode]

The spacecraft will orbit Jupiter 32 times, skimming to within 3,100 miles (5,000 kilometers) above the planet's cloud tops, for approximately one year. Juno uses a spinning solar-powered spacecraft in a highly elliptical polar orbit that avoids most of Jupiter's high radiation regions. The designs of the individual instruments are straightforward and the mission does not require the development of any new technologies
Juno's scientific payload includes:

1. A gravity/radio science system (Gravity Science) (Done with high gain antenna which is on top of spacecraft).

2. A six-wavelength microwave radiometer for atmospheric sounding and composition (MWR):

Juno six-wavelength microwave radiometer

A six-wavelength microwave radiometer

3. The vector magnetometer (MAG):

juno-magnometer

The vector magnometer at the end of the solar array

4. Plasma and energetic particle detectors (JADE and JEDI):

Juno Jade

JADE

OLYMPUS DIGITAL CAMERA

JEDI

5. A radio/plasma wave experiment (Waves) .

6. An ultraviolet imager/spectrometer (UVS)

7. An infrared imager/spectrometer (JIRAM) :

8.The spacecraft will also carry a color camera, called the JunoCam, to provide the public with the first detailed glimpse of Jupiter's poles.

Juno gravity science and other instruments

This is my first report on this particular mission.  It will change over time into a different form possibly updates when they occur just like the other missions I write about.  When the next one comes out I cannot say, but when it does I will be one of the first to post new information on this mission when it occurs.