Date: August 4, 2011
Title: Juno, New Frontiers to Jupiter
Podcaster: Tony Rice
Links: Sky and Telescope, September 2011
Sky and Telescope editor Robert Naeye interview with Juno PI Scott Bolton
NASA Juno Mission page: http://www.nasa.gov/juno
South West Research Institute Juno website: http://missionjuno.swri.edu/
Wisconsin mission page: http://juno.wisc.edu/spacecraft.html
http://newfrontiers.nasa.gov/missions_juno.htm
Description: NASA is preparing for the launch of the Juno mission to Jupiter. Juno is the latest in the New Frontiers program of medium-class spacecraft conducing very focused investigations of our solar system.
Bio: Tony Rice is one of 150 lucky participants in the Juno launch tweet-up braving the Florida heat at the Kennedy Space Center today. He’s an amateur astronomer from Cary, North Carolina and a volunteer in the NASA/JPL Solar System Ambassador Program. I get to go into schools, visit with scout programs and talk about space.
Sponsor: This episode of 365 Days of Astronomy is sponsored anonymously.
Transcript:
My name is Tony Rice, I’m an JPL Solar System Ambassador from NC and one of 150 lucky participants in the Juno launch tweet-up braving the Florida heat at the Kennedy Space Center today. We are preparing for the launch of the Juno mission to Jupiter. Juno is the latest in NASA’s New Frontiers program of medium-class spacecraft conducing very focused investigations of our solar system.
An Atlas V rocket has been readied at Cape Canaveral Air Force Station at Space Launch Complex 41 the same pad where New Horizons set off for Pluto 5 years earlier. Juno herself arrived last Wednesday, encased in the payload faring after final tests at the Astrotech pre-launch processing facility just outside the gates of the Kennedy Space Center , in Titusville. Tomorrow, weather and technology permitting, that Atlas V, strapped with 5 solid rocket boosters will lift off from the pad at 11:34 a.m. on a 5 year journey to Jupiter .
Minutes after launch, Juno will extend it’s tractor trailer sized solar panels giving the spacecraft a span of about 60 feet. This first time solar power has been used on an orbiting spacecraft this far out where25 times less sunlight is available than here on Earth. Those solar panels start out producing 12kw of power here on Earth but drop to 400w as the spacecraft reaches Jupiter, not enough to run a hair dryer but sufficient for Juno with about half that power going to the instruments on board and the the other half going to housekeeping items like running heaters to keep the instruments warm.
Next, the Centaur stage will spin up the spacecraft to between 1 and 2 RPM providing for stability, the same technique used on long lived spacecraft like Pioneer 10 and 11 which also visited Jupiter over 35 years ago. This rotation making the spacecraft look as it cartwheeling it’s way through space, also allows the instruments on board to make their complete observations of the planet from between the extended solar arrays while keeping those solar arrays pointed to the sun at all times.
The instruments onboard Juno include:
* A gravity science system which will probe Jupiter’s mass via Doppler tracking
* A microwave radiometer performing atmospheric sounding deep into the atmosphere
* The Jupiter Energetic-particle Detector Instrument (JEDI), Jovian Auroral Distributions Experiment (JADE) and just as important though not as coolly named Microwave Radiometer, which together will sample electric fields, plasma waves and particles around Jupiter in an effort to learn more about how the magnetic field is connected to the atmosphere, especially around Jupiter’s northern and southern auroras.
* The Belgian built UVS and the Italian Space Agency built JIRAM – ultraviolet and infrared imagers/spectrometers respectively
* And my favorite, JunoCam Ð which promises to provide some spectacular full color close-ups of the planet.
These sensitive instruments are encased in a tank like titanium radiation vault to protect them from the harsh environment they will operate in. That environment was described by the mission’s Principal Investigator as ‘probably the harshest radiation environment in the solar system other than just going directly to the sun’.
Lockheed Martin built the spacecraft, the Jet Propulsion Laboratory manages the mission and the Principal Investigator is Dr. Scott Bolton of the Southwest Research Institute. Additionally students at Pine Ridge High School in Deltona, FL are participating via a radio telescope program contributing to the science leading up to and continuing after the launch of Juno.
But why the name Juno? What does it stand for? This time, thankfully, it doesn’t stand for anything.
After considering a number of acronym-based names in a contest among the team members, a mythology buff suggested Juno. In Roman mythology the god Jupiter cast a veil of clouds over himself in an attempt to hide the tryst with the nymph Io from his goddess wife Juno. Juno was suspicious of Jupiter and used her power to penetrate those clouds and see the true nature of Jupiter. The name is a perfect fit for this mission.
Fast forward 5 years where Juno will arrive at and orbit Jupiter. Each highly elliptical 11 day polar orbit extends out past Jupiter’s moon Europa in a flight plan designed to minimizing radiation exposure to the science instruments by dropping below the planet’s radiation belts. Those polar orbits allow the whole planet to be mapped very very closely, from just a few thousand kilometers above the cloud tops.
But why Jupiter? Jupiter is by far the largest planet in the solar system and it has an influence on everything in the solar system. Hollywood might have us believe that brave oil drillers turned astronauts must keep the Earth safe from planet killing asteroids but its Jupiter has done a pretty good job, using it’s incredible mass as a vacuum cleaner devouring anything that ventures near. Jupiter also keeps the asteroid belt between it an Mars in check and probably keeps that belt from turning into another inner planet for the IAU to demote.
7 missions have visited Jupiter including Fly-By missions Pioneer 10 and 11, Voyager 1 and 2. Ulysses took advantage of Jupiter’s gravity to redirect itself towards it’s primary mission of studying the poles of the sun, taking measurements of the Jovian magnetic and radiation levels as it passed. The Galileo mission was the first to orbit Jupiter teaching us about it’s atmosphere but left us with many questions about its interior Most recently Cassini flew by Jupiter on it’s way to Saturn using the encounter as an opportunity to test it’s instruments and sent back some incredible images in the process. So why an 8th mission to visit our biggest neighbor?
As our solar system was in it’s infancy, Jupiter is believed to have been the first planet to form. Understanding the makeup and formation of Jupiter is key to understanding the origin of our solar system. There is much left to learn about Jupiter. Galileo taught us much but it brought new questions that Juno seeks to help answer:
1. What’s really under all those clouds? Does Jupiter have a core of heavy elements, and if so how large is it? How does it rotate?
2. How much water is in Jupiter?
3. How deep into the atmosphere do the Great Red Spot, as big as 2 or 3 Earths and 300 or more years old, reach?
4. How different is the composition of Jupiter from the original solar nebula, and if it’s different, what is the cause?
These questions will be answered by Juno’s gathering information on Jupiter’s magnetic and gravitational fields. Juno will significantly advance our understanding of the early evolution of our own solar system at the most fundamental level by improving of our understanding of formation and structure of our largest planet which will .
Sources:
Sky and Telescope, September 2011
Sky an d Telescope editor Robert Naeye interview with Juno PI Scott Bolton
NASA Juno Mission page: http://www.nasa.gov/juno
South West Research Institute Juno website: http://missionjuno.swri.edu/
Wisconsin mission page: http://juno.wisc.edu/spacecraft.html
http://newfrontiers.nasa.gov/missions_juno.html
July 27, 2011 1pm Eastern – NASA Science News Conference to Preview Upcoming Mission to Jupiter with KSC PAO, Jim Green, director, Planetary Science Division NASA HQ, PI Scott Bolton, JPL Juno project manager Jan Chodas, and Pine Ridge High School Juno Education program participant Kaelyn Badura
End of podcast:
365 Days of Astronomy
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