Discussing Juno/JunoCam Mission and Jupiter Data

1oldman2 · Oct 26, 2016

Here's the latest from JPL
http://www.nasa.gov/feature/jpl/nasas-juno-mission-exits-safe-mode-performs-trim-maneuver

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.

"Juno exited safe mode as expected, is healthy and is responding to all our commands," said Rick Nybakken, Juno project manager from NASA's Jet Propulsion Laboratory in Pasadena, California. "We anticipate we will be turning on the instruments in early November to get ready for our December flyby."

In preparation for that close flyby of Jupiter, Juno executed an orbital trim maneuver Tuesday at 11:51 a.m. PDT (2:51 p.m. EDT) using its smaller thrusters. The burn, which lasted just over 31 minutes, changed Juno’s orbital velocity by about 5.8 mph (2.6 meters per second) and consumed about 8 pounds (3.6 kilograms) of propellant. Juno will perform its next science flyby of Jupiter on Dec. 11, with time of closest approach to the gas giant occurring at 9:03 a.m. PDT (12:03 p.m. EDT). The complete suite of Juno’s science instruments, as well as the JunoCam imager, will be collecting data during the upcoming flyby.

"We are all excited and eagerly anticipating this next pass close to Jupiter," said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. "The science collected so far has been truly amazing."

1oldman2 · Nov 7, 2016

http://spacenews.com/nasa-investigating-possible-link-between-juno-and-intelsat-thruster-problems/

JPL spokesman D.C. Agle said Nov. 2 there were no updates on the Juno thruster investigation. He added, though, that the Dec. 11 close approach will be a "science pass," with no plans to fire the engine.

Green noted that Juno can still carry out its mission in its current orbit, since the bulk of the data it collects is during the close approaches to the planet. The maneuver, though, would reduce the spacecraft ’s period from 53 to 14 days, giving it more flybys and opportunities to gather more data in a given period of time.

"We want to really take a good look at it and get it down into its lower orbit if at all possible," he said, "if we feel like that’s a risk we can take with the system that we have onboard."

1oldman2 · Nov 26, 2016

Normally I'm very happy to hear of a mission being extended, however this "extension" is one I'm hoping doesn't come to pass. I really would like to see a successful burn accomplished to get the 14 day orbit established, At any rate the December pass should have more interesting data as long as another "safe mode event" doesn't occur. In the meantime "wait and see" is all anyone can do, still no word on the valve issue or a work around that will safely let the required burn be accomplished.

http://www.planetary.org/blogs/emily-lakdawalla/2016/11030800-juno-update.html
At the DPS/EPSC meeting last week, principal investigator Scott Bolton spoke about keeping Juno in its long, 53.5-day orbit for a long time, not ruling out the possibility of performing the entire mission in such an orbit. Juno only gets exposed to dangerous radiation when very close to Jupiter, so the spacecraft wouldn't be exposed to any additional radiation by doing this, though it would seriously prolong the mission. If the mission has not ended by September 2019, Jupiter will have traveled far enough around the Sun that Juno will pass into Jupiter's shadow for several hours on every orbit, a condition that it was not designed for and which could harm its power system; the mission would need to develop a solution to that problem.

1oldman2 · Dec 10, 2016

https://www.nasa.gov/feature/jpl/nasa-juno-mission-prepares-for-december-11-jupiter-flyby
On Sunday, December 11, at 9:04 a.m. PST (12:04 p.m. EST, 17:04 UTC) NASA’s Juno spacecraft will make its third science flyby of Jupiter.

At the time of closest approach (called perijove), Juno will be about 2,580 miles (4,150 kilometers) above the gas giant’s roiling cloud tops and traveling at a speed of about 129,000 mph (57.8 kilometers per second) relative to the planet. Seven of Juno’s eight science instruments will be energized and collecting data during the flyby.

Mission managers have decided not to collect data with the Jovian Infrared Auroral Mapper (JIRAM) instrument during the December flyby, to allow the team to complete an update to the spacecraft software that processes JIRAM’s science data. A software patch allowing JIRAM’s operation is expected to be available prior to the next perijove pass (PJ4) on Feb. 2, 2017.

Apparently no one wants to gamble a functioning 1.1 billion dollar spacecraft , we may be in for 53.4 day orbits for a while, at least until JPL is feeling more confident in the main engine.

The spacecraft team continues to weigh its options regarding modifications of Juno’s orbital period -- how long it takes for the spacecraft to complete one orbit around Jupiter. At present, Juno’s orbital period is 53.4 days. There had been plans to perform a period adjustment maneuver with the spacecraft ’s main engine on Oct. 19 to reduce the orbital period to 14 days. The team made the decision to forgo the maneuver 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 maneuver was the final scheduled burn of Juno's main engine.

1oldman2 · Dec 15, 2016

Data is beginning to come in from the latest pass, I'll post what I can come up with.
http://www.jpl.nasa.gov/spaceimages/details.php?id=pia21219
This image, taken by NASA's Juno spacecraft 's JunoCam imager, highlights the seventh of Jupiter's eight 'string of pearls' -- massive counterclockwise rotating storms that appear as white ovals in the gas giants southern hemisphere. Since 1986, these white ovals have varied in number from six to nine. There are currently eight white ovals visible.

1oldman2 · Dec 15, 2016

Still digging but here is a start.
http://spaceflight101.com/juno-delivers-new-data-from-jupiter-future-flight-plan-under-evaluation/

NASA’s Juno spacecraft brushed past Jupiter on Sunday, marking the mission’s first operational science data collection with seven of the craft’s instruments active as the probe zipped past the Gas Giant at a speed over 200,000 Kilometers per hour.

According to NASA, the close flyby was successful and Juno collected a full complement of science data that was being downlinked to Earth at the start of the week. The agency also announced that concrete plans on a possible orbital adjustment are still being worked out as the mission team, in coordination with spacecraft engineers, evaluate the available options for modifying Juno’s orbit.

Three options exist for the future of the Juno mission: 1) keeping the spacecraft in its current orbit with science passes every 53.5 days, 2) firing the main engine for a full or partial period reduction to increase the frequency of science passes, 3) employing the monopropellant reaction control system to accomplish a partial period reduction to avoid the risk of firing the main engine, though at the expense of maneuvering propellant that could be useful in an extended mission.

1oldman2 · Dec 22, 2016

Here is one I haven't seen yet, It's from Perijove three on December 11th, looking at the southern Hemisphere from a distance of 37,000 km. ( I came across this on APOD, https://apod.nasa.gov/apod/ap161217.html) I'm going to have to look around and see what other "Jcam" images I've missed from the latest pass.