July 4, 2016 – NASA’s Juno spacecraft, built by Lockheed Martin, successfully entered Jupiter’s orbit during a 35-minute engine burn on Monday, July 4. Confirmation that the burn had completed was received on Earth at 9:53 p.m. MDT (11:53 p.m. EDT). The spaceflight’s operations were controlled by a joint team at Lockheed Martin’s Mission Support Area near Denver and NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California.
“Independence Day always is something to celebrate, but today we can add to America’s birthday another reason to cheer – Juno is at Jupiter,” said NASA administrator Charlie Bolden. “And what is more American than a NASA mission going boldly where no spacecraft has gone before? With Juno, we will investigate the unknowns of Jupiter’s massive radiation belts to delve deep into not only the planet’s interior, but into how Jupiter was born and how our entire solar system evolved.”
After a nearly five-year journey, confirmation of a successful orbit insertion was received from Juno tracking data monitored at the Lockheed Martin Juno operations center, as well as at the navigation facility at JPL. The telemetry and tracking data were received by NASA’s Deep Space Network antennas in Goldstone, California and Canberra, Australia.
“Tonight, 540 million miles away, Juno performed a precisely choreographed dance at blazing speeds with the largest, most intense planet in our solar system,” said Guy Beutelschies, director of Interplanetary Missions at Lockheed Martin Space Systems. “Since launch, Juno has operated exceptionally well, and the flawless orbit insertion is a testament to everyone working on Juno and their focus on getting this amazing spacecraft to its destination. NASA now has a science laboratory orbiting Jupiter.”
Preplanned events leading up to the orbital insertion burn included changing the spacecraft’s attitude to point the main engine in the desired direction and then increasing the spacecraft’s rotation from 2 to 5 revolutions per minute (RPM) to help stabilize it.
The final commands for the orbit insertion were sent to Juno four days ago, and basically put it into autopilot. At 9:18 p.m. MDT today, those commands fired the large 645-Newton Lero-1b main engine for a 35-minute burn that slowed the spacecraft by 1,212 miles per hour (542 meters per second). This allowed it to be captured by Jupiter’s massive gravity and placed into a large elliptical polar orbit around the planet that is initially 53.5 days long. By mid-October, the orbit will be reduced to 14 days for science observations.
“The spacecraft worked perfectly, which is always nice when you’re driving a vehicle with 1.7 billion miles on the odometer,” said Rick Nybakken, Juno project manager from JPL. “Jupiter orbit insertion was a big step and the most challenging remaining in our mission plan, but there are others that have to occur before we can give the science team the mission they are looking for.”
Soon after the burn was completed, Juno turned so that the sun’s rays could once again reach the 18,698 individual solar cells that power the spacecraft.
Juno will now begin its commissioning phase. Over the next few months, Juno’s mission and science teams will perform final testing on the spacecraft’s subsystems, final calibration of science instruments and some science collection.
During its mission of exploration, Juno will circle the Jovian world 37 times, soaring low over the planet’s cloud tops – as close as about 2,600 miles (4,100 kilometers). During these flybys, Juno will probe beneath the obscuring cloud cover of Jupiter and study its auroras to learn more about the planet’s origins, structure, atmosphere and magnetosphere. The mission will help us understand how giant planets form and the role these titans played in putting together the rest of the solar system. Jupiter can also provide critical knowledge for understanding the planetary systems being discovered around other stars.
“Our official science collection phase begins in October, but we’ve figured out a way to collect data a lot earlier than that,” said Bolton. “Which, when you’re talking about the single biggest planetary body in the solar system, is a really good thing. There is a lot to see and do here.”
In fact, during the post-insertion press conference, NASA released a video of Jupiter and its four largest moons – Io, Europa, Ganymede and Callisto. The video is made up of still frames and combined into a unique time-lapse movie. The movie begins on June 12th with Juno 10 million miles from Jupiter, and ends on June 29th, 3 million miles distant. Bolton said this movie already contains some exciting science because Callisto is much dimmer than its siblings, and scientists didn’t expect that. Now scientists will puzzle over the reason for this difference.
The Juno spacecraft launched on August 5, 2011, atop a United Launch Alliance Atlas V rocket from Cape Canaveral Air Force Station in Florida.
JPL manages the Juno mission for NASA. The mission’s principal investigator is Scott Bolton of Southwest Research Institute in San Antonio. The mission is part of NASA’s New Frontiers Program, managed at the agency’s Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space Systems in Littleton, Colorado built the spacecraft and is on the flight operations team with JPL.
CU-Boulder Professor Fran Bagenal of the Laboratory for Atmospheric and Space Physics (LASP) co-chairs the Juno Magnetospheric Working Group for NASA and is coordinating many of the science observations for the mission. In addition to Bagenal, LASP Professor Robert Ergun and Research Associate Robert Wilson are part of the Juno science team. Other CU-Boulder Juno participants include undergraduate Kaleb Bodisch, 2015 graduate Logan Dougherty, now a researcher, and graduate students Drake Ranquist and Edward Nerney.