NASA Juno Spacecraft Successfully Completes First Thruster Burn For 2013 Earth Fly-By
August 31, 2012

NASA Juno Spacecraft Successfully Completes First Thruster Burn For 2013 Earth Fly-By

Lawrence LeBlond for - Your Universe Online

NASA´s Jupiter orbiter Juno successfully fired its engine Thursday as it prepares to make a crucial fly-by around Earth to give it the momentum it needs to shoot off toward the solar system´s largest planet.

The firing of the main engine lasted just short of 30 minutes, and should give the spacecraft, which is currently about 300 million miles away, the push it needs to make the boomerang pass. The maneuver is the first of two needed to garner enough momentum for Juno to have a shot of reaching the gas giant Jupiter, according to NASA mission controllers.

Using the gravity of Earth as momentum, Juno should accelerate toward the outer solar system. The fly-by is expected to occur on October 9, 2013, and after a second firing puts Juno on the right path, it should reach Jupiter on or around July 4, 2016.

The deep-space firing began at 6:57 p.m. EDT on Thursday August 30, when the Leros-1b main engine was fired for 29 minutes 39 seconds. The team believes the firing time was accurate and changes its velocity by about 770 mph. The burn consumed about 829 pounds of fuel.

“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, California. “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“¦ There is a lot that goes into a main engine burn.”

A second deep-space burn is planned for September 4, and will give Juno the oomph it needs to make the planned fly-by and final push toward our giant neighbor. The earthen fly-by will boost Juno´s velocity by 16,330 mph, a speed equivalent to traveling from New York to San Francisco in less than 12 minutes. The planned engine burns follow a thruster burn earlier this year by NASA mission controllers to refine the orbiters path.

Juno, which has been on its mission now for a little more than a year (launched August 5, 2011), is not the first spacecraft to visit Jupiter. More than a half dozen satellites and orbiters have visited the gas giant since the 1970s, but none have been as sophisticated as Juno. Juno promises to venture closer and deeper to the planet´s evolution. It will peer through the planet´s dense cloud cover to map its magnetic and gravitational fields. Scientists hope by doing so, they will get a better understanding of how the solar system was formed.

Once Juno reaches its destination, it is scheduled to circle Jupiter 33 times, from pole-to-pole, using its collection of eight instruments to probe the planet. The data provided by the instruments should give scientists more information on the planet´s origins, structure, atmosphere and magnetosphere. They also hope to find whether or not the planet has a solid planetary core.

Perhaps one of Juno´s most astonishing feats will have nothing to do with Jupiter itself. If Juno does reach the planet, it will be the first solar-powered spacecraft to venture so far from the sun. Its three solar panels, each about the size of a semi, will power the craft during its entire mission to the gas giant, except for a few thruster burns here and there to keep it on the right path.

Juno is designed, and scheduled, to spend one year studying Jupiter before crashing into it. By crashing the spacecraft into the planet, they are protecting the moons that orbit Jupiter. Scientists believe one of the moons, Europa, contains a liquid ocean beneath its surface.

NASA´s Juno mission is spearheaded by the Jet Propulsion Laboratory in Pasadena, California. Principal investigator for the mission is Scott Bolton of Southwest Research Institute in San Antonio, Texas. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space Systems built the spacecraft.