Glitch Delays Juno Engine Firing For Jupiter Mission

By  //  September 5, 2012

Key NASA Research

BREVARD COUNTY • CAPE CANAVERAL, FLORIDA – In just its second year of a five-year voyage to Jupiter, the Juno spacecraft may not be drawing headlines, but its mission remains a key research project for NASA.

An artist's conception of NASA's Juno spacecraft which is in its second year of travel to study the planet Jupiter. It is expected to arrive at Jupiter in July 2016. (Image courtesy NASA)

Launched on Aug. 5, 2011 from Launch Complex 41 at Cape Canaveral Air Force Station, Juno has traveled 425 million miles so far, about 22 percent of the distance it will eventually cover before arriving at Jupiter around July 4, 2016.

NASA’s Jet Propulsion Laboratory in California is managing the Juno mission, which will examine the composition, gravity and polar magnetosphere on Jupiter.

An Atlas V rocket with NASA’s Juno spacecraft lifts off from Space Launch Complex 41 of the Cape Canaveral Air Force Station on Aug. 5, 2011. (Image courtesy of Pat Corkery, United Launch Alliance)


The spacecraft will study how Jupiter was formed, if the giant planet has a rocky core, how much water is in its atmosphere and measure Jupiter’s wind speeds, which are thought to exceed 370 mph.

With an array of scientific instruments aboard, Juno will collect data about water on Jupiter by detecting microwave radiation from its atmosphere.

And in studying if Jupiter has a dense core, scientists will be able to prove if theories about how the planet was formed are correct.

Much of this will be accomplished by Juno by mapping Jupiter’s gravitational and magnetic fields better than ever before and for the first time, scientists will have a clearer picture of the planet’s interior structure.

By determining the ratio of oxygen to hydrogen on Jupiter, the Juno spacecraft will clarify for scientists and astronomers Jupiter’s formation in the solar system.

A Jupiter polar aurora in ultaviolet is captured by the Hubble Space Telescope. Bright streaks and dots are caused by magnetic flux tubes connecting Jupiter to its largest moons. (Image courtesy NASA)

Polar Auroras

Juno also will explore the three-dimensional structure of Jupiter’s polar auroras.

The spacecraft currently is traveling at a speed of 35,800 mph and NASA reports all systems aboard Juno are operating fine.

On June 20, NASA 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.

The first of those maneuvers took place late last week.

However, NASA delayed a final burn Tuesday necessary to use Earth’s gravity to propel the Juno spacecraft to Jupiter.

The second engine burn was pushed back after high pressure was discovered in the Juno propulsion system.

Engineers will review data and then make a recommendation for a fix, with the burn now set for Sept. 14.

Two successful burns are required to slingshot the spacecraft on the flight to Jupiter.

Even with the engine firing delay, Juno remains on target to arrive at Jupiter in 2016.