Updates Juno Mission News and Updates

[RisingFury]

Juno downlinking 120kbit/sec right now, at -128dBm (per DSN Now). That's around 180 atto-Watts of power. Just stunning how humankind can not only detect that low a power, but stream kilobits of data over it ....


1 / 100-billionth of the power of a received WiFi signal. smh in amazement.

I know, but we still can't make a wifi that's worth a damn :lol:

 

[sorindafabico]

Juno downlinking 120kbit/sec right now, at -128dBm (per DSN Now). That's around 180 atto-Watts of power. Just stunning how humankind can not only detect that low a power, but stream kilobits of data over it ....


1 / 100-billionth of the power of a received WiFi signal. smh in amazement.

If my calculation isn't wrong, the number of photons is of the same order of magnitude you get from Vega with a Johnson V filter in a 10 cm telescope.

(The number of photons from Vega detected per second in the V filter is about 10^6 per cm^2 - got from a book)

 

[Urwumpe]

Juno downlinking 120kbit/sec right now, at -128dBm (per DSN Now). That's around 180 atto-Watts of power. Just stunning how humankind can not only detect that low a power, but stream kilobits of data over it ....


1 / 100-billionth of the power of a received WiFi signal. smh in amazement.

Well, you only need a 70m antenna with supercooled receivers... compare this to your WiFi equipment. If you would cool your smart phone to -100°C, you could sure get some better range with it....

 

[Notebook]

http://www.bbc.co.uk/news/science-environment-36780756

The American space agency's new Juno mission to Jupiter has returned its first imagery since going into orbit around the gas giant last week.

The picture shows a sunlit portion of the planet, together with three of its big moons - Io, Europa and Ganymede.

The fourth major satellite - Callisto - is out of view.

 

[Notebook]

A new probe at Jupiter, flown by the US space agency Nasa, is about to make its first close approach to the planet since going into orbit in July.

Juno will pass just 4,200km above the cloud tops of the gas giant on Saturday.

No previous spacecraft has got so close to the world during the main phase of its mission.

Juno will have all its instruments - and its camera - switched on for the encounter.

http://www.bbc.co.uk/news/science-environment-37200337

 

[boogabooga]

No previous spacecraft has got so close to the world during the main phase of its mission.

So, we are not counting the Galileo atmospheric-entry probe for some reason...? :huh:

 

[DaveS]

So, we are not counting the Galileo atmospheric-entry probe for some reason...? :huh:

I would not count it as a spacecraft as it didn't have any spacecraft specific systems. It was completely ballistic in terms of flight dynamics and had only science equipment when you deleted the TPS. It was essentially a cannon ball equipped with science gear.

 

[boogabooga]

I would not count it as a spacecraft as it didn't have any spacecraft specific systems. It was completely ballistic in terms of flight dynamics and had only science equipment when you deleted the TPS. It was essentially a cannon ball equipped with science gear.

So?

Sputnik and Explorer didn't have any fancy "spacecraft systems" and were completely ballistic in terms of flight dynamics. What does the TPS have to do with science equipment?

Seems quite a stretch to me.

Edit:

I recognize that there is a point to be made about JUNO here, but IMHO it could be made more precisely.

 

[K_Jameson]

Let's say that Juno holds the record for a Jupiter close-encounter for a spacecraft that isn't in a collision course with the planet.

 

[boogabooga]

I agree.

 

[orb]

NASA: Jupiter’s North Pole Unlike Anything Encountered in Solar System

The Planetary Society Blog - Emily Lakdawalla: Juno's instruments return riches from first perijove
[ame="https://www.youtube.com/watch?v=l8apkaqUF-k"]JunoCam MarbleMovie parts 1 to 7 level2 - YouTube[/ame]
JunoCam data: Perijove 1 (August 27, 2016)

NASASpaceflight.com:Juno provides new data on Jupiter; readies for primary science mission

 

[orb]

Slate - Bad Astronomy: Jupiter, the (Surprising and Weird) King of the Planets

 

[orb]

NASA JPL: 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 maneuver (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 maneuver was the final scheduled burn of Juno's main engine.

"Telemetry indicates that two helium check valves that play an important role in the firing of the spacecraft's main engine did not operate as expected during a command sequence that was initiated yesterday," said Rick Nybakken, Juno project manager at NASA's Jet Propulsion Laboratory in Pasadena, California. "The valves should have opened in a few seconds, but it took several minutes. We need to better understand this issue before moving forward with a burn of the main engine."

After consulting with Lockheed Martin Space Systems of Denver and NASA Headquarters, Washington, the project decided to delay the PRM maneuver at least one orbit. The most efficient time to perform such a burn is when the spacecraft is at the part of its orbit which is closest to the planet. The next opportunity for the burn would be during its close flyby of Jupiter on Dec. 11.

{...}

 

[boogabooga]

Uh oh.

 

[Unstung]

To elaborate on that uh oh: "Juno Spacecraft in Safe Mode for Latest Jupiter 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. The spacecraft acted as expected during the transition into safe mode, restarted successfully and is healthy. High-rate data has been restored, and the spacecraft is conducting flight software diagnostics. All instruments are off, and the planned science data collection for today’s close flyby of Jupiter (perijove 2), did not occur.

“At the time safe mode was entered, the spacecraft was more than 13 hours from its closest approach to Jupiter,” said Rick Nybakken, Juno project manager from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We were still quite a ways from the planet’s more intense radiation belts and magnetic fields. The spacecraft is healthy and we are working our standard recovery procedure.”

The spacecraft is designed to enter safe mode if its onboard computer perceives conditions are not as expected. In this case, the safe mode turned off instruments and a few non-critical spacecraft components, and it confirmed the spacecraft was pointed toward the sun to ensure the solar arrays received power.

Mission managers are continuing to study an unrelated issue with the performance of a pair of valves that are part of the spacecraft’s propulsion system. Last week the decision was made to postpone a burn of the spacecraft’s main engine that would have reduced Juno’s orbital period from 53.4 to 14 days.

The next close flyby is scheduled on Dec. 11, with all science instruments on.

[...]

 

[mahdavi3d]

spaceflight101.com : Juno Spacecraft Recovers from Safe Mode, adjusts Orbit for next Jupiter Pass

 

[orb]

Universe Today: JUNO JUST TOOK ONE OF THE BEST IMAGES OF JUPITER EVER

NASA: Juno’s Close Look at a Little Red Spot

Slate - Bad Astronomy: The Broad Strokes of Jupiter

(Click for bigger version)​

 

[K_Jameson]

Cassini achieved a similar resolution photomosaic (OK, OK, from an equatorial perspective) as he passed a hundred of times farther from Jupiter.
Imagine if Juno had some real cameras and not that toy...

 

[Unstung]

Imagine if Juno had some real cameras and not that toy...

You've got to remember that Juno is rotating, so a narrow angle camera like on Cassini would probably return blurry images. This is not to say that Junocam couldn't have been more capable or better shielded, but it isn't relevant to the mission's scientific objectives.

 

[K_Jameson]

You've got to remember that Juno is rotating, so a narrow angle camera like on Cassini would probably return blurry images.

Yeah. Surely a narrow angle camera would require a different platform. A three-axis stabilized spacecraft is needed. Or a dual-spin like Galileo. But the costs...
But I don't mean necessarily a NAC. A wide angle camera with larger opticals than the tiny Junocam would be anyway desirable.

This is not to say that Junocam couldn't have been more capable or better shielded, but it isn't relevant to the mission's scientific objectives.

To me, going to Jupiter without a camera is a nonsense. Especially if we venture in a never explored zone with the opportunity to take images like never before. Glad that at least the Junocam is aboard, at the end.