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NASA's Juno Mission Exits Safe Mode, Performs Trim Manoeuvre

NASA's Juno spacecraft at Jupiter has left safe mode and has successfully completed a minor burn of its thruster engines in preparation for its next close flyby of Jupiter.
Mission controllers commanded Juno to exit safe mode Monday, Oct. 24, with confirmation of safe mode exit received on the ground at 10:05 a.m. PDT (1:05 p.m. EDT). The spacecraft entered safe mode on Oct. 18 when a software performance monitor induced a reboot of the spacecraft's onboard computer. The team is still investigating the cause of the reboot and assessing two main engine check valves.
 
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Juno Spacecraft in Safe Mode for Latest Jupiter Flyby Scientists Intrigued by Data from First Flyby

NASA's Juno spacecraft entered safe mode Tuesday, Oct. 18 at about 10:47 p.m. PDT (Oct. 19 at 1:47 a.m. EDT). Early indications are a software performance monitor induced a reboot of the spacecraft's onboard computer.
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Mission Prepares for Next Jupiter Pass

Mission managers for NASA's Juno mission to Jupiter have decided to postpone the upcoming burn of its main rocket motor originally scheduled for Oct. 19. This burn, called the period reduction manoeuvre (PRM), was to reduce Juno's orbital period around Jupiter from 53.4 to 14 days. The decision was made in order to further study the performance of a set of valves that are part of the spacecraft's fuel pressurization system. The period reduction manoeuvre was the final scheduled burn of Juno's main engine.
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NASA's Juno Team to Discuss Jupiter Mission Status, Latest Science Results

Team members of NASA's Juno mission to Jupiter will discuss the latest science results, an amateur imaging processing campaign, and the recent decision to postpone a scheduled burn of its main engine, during a media briefing at 4 p.m. EDT Wednesday, Oct. 19. The briefing will air live on NASA Television and stream on the agency's website.
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Title: A possible new test of general relativity with Juno
Authors: L. Iorio

The expansion in multipoles of the gravitational potential of a rotating body affects the orbital motion of a test particle orbiting it with long-term perturbations both at a classical and at a relativistic level. In this preliminary sensitivity analysis, we show that, for the first time, the J2 c^-2 effects could be measured by the ongoing Juno mission in the gravitational field of Jupiter during its yearlong science phase (10 November 2016-5 October 2017) thanks to its high eccentricity (e=0.947) and to the huge oblateness of Jupiter (J2=1.47 10^-2). The semi-major axis a and the perijove \omega\ of Juno are expected to be shifted by \Delta a =700-900 m and \Delta\omega = 50-60 milliarcseconds, respectively, over 1-2 yr. A numerical analysis shows also that the expected J2c^-2 range-rate signal for Juno should be as large as 280 microns per second during a typical 6 h pass at its closest approach. Independent analyses previously performed by other researchers about the measurability of the Lense-Thirring effect showed that the radio science apparatus of Juno should reach an accuracy in Doppler range-rate measurements of 1-5 microns per second over such passes. The range-rate signature of the classical even zonal perturbations is different from the 1PN one. Thus, further investigations, based on covariance analyses of simulated Doppler data and dedicated parameters estimation, are worth of further consideration. It turns out that the J2 c^-2 effects cannot be responsible of the flyby anomaly in the gravitational field of the Earth. A dedicated spacecraft in a 6678 km X 57103 km polar orbit would experience a geocentric J2 c^-2 range-rate shift of 0.4 mm s^-1.

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Juno's Two Deep Space Manoeuvres are 'Back-To-Back Home Runs'

NASA's Juno spacecraft successfully executed a second Deep Space Manoeuvre, called DSM-2 last Friday, Sept. 14. The 30 minute firing of its main engine refined the Jupiter-bound 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 manoeuvre began at 22:30 UT, when the Leros-1b main engine began to fire. The burn ended at 23:00 UT. Based on telemetry, the Juno project team believes the burn was accurate, changing the spacecraft's velocity by about 388 meters a second while consuming about 376 kilograms of fuel.

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Nasa's Juno spacecraft will execute the second of two big burns on its main engine on Tuesday.
The manoeuvre will put the probe on a path to flyby Earth in October next year. This sweep around the home planet will then give the mission a gravitational boost and the velocity required to get it out to Jupiter in July 2016.

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NASA's Jupiter-Bound Juno Changes its Orbit

Navigators and mission controllers for NASA's Juno mission to Jupiter watched their computer screens as their spacecraft successfully performed its first deep-space manoeuvre. 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 manoeuvre began at 22:57 UT yesterday, 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 344 metres a second while consuming about 376 kilograms of fuel.

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The Juno Jupiter mission launched on the 5th August, 2011, from Cape Canaveral, Florida



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Juno mission to Jupiter may get more science assignments

Juno's elliptical path calls for it to loop back around Earth next year to pick up a gravitational slingshot boost toward Jupiter.
The meetings at Marshall, which manages the NASA program that includes Juno, were to review the plan in terms of cost, staffing and schedule, NASA said. They were to make sure NASA and the Juno team were on the same page even though Juno is still a long way from Jupiter.

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