Juno Mission Update 8/31/12

 

 

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.

 

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.

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).

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 .

 

The Early Asteroid Belt

Juno Mission Update 8/8/12

 

 

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’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.

 

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.

 

Auroras at Jupiter's North and South Poles

Jupiter’s Auroras