Talk:Juno (spacecraft)/Archive 1

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Archive 1

Solar Panel Output

Since Jupiter has a perihelion and aphelion distance of 4.95 AU and 5.46 AU repectively, it receives between 1/25th and 1/30th of the sunlight levels we receive at Earth's distance from the Sun. So why then does the article state:-

"The total area of the arrays is over 60 square metres (650 sq ft). This is enough to produce over 18 kilowatts (24 hp) while in Earth orbit, and just over 400 watts (0.54 hp) while on Jupiter orbit."

Surely if the solar panels could produce 18kW of power in Earth orbit, they'd produce between 600 and 720 Watts in Jovian orbit? One of these figures must therefore be incorrect! CrackDragon (talk) 20:22, 31 July 2010 (UTC)

That assumes that you have a perfectly empty vacuum. If you have any sort of intervening material - dust, gasses, etc. - that could reduce the intensity of the light received by more than just increasing the distance would. 71.134.236.97 (talk) 08:29, 8 August 2010 (UTC)

This has nothing to do with dust, which absorbs no more than 1/10,000,000th of the light. The output drops faster because it is a non-linear function of the light intensity. Ruslik_Zero 08:37, 8 August 2010 (UTC)
With the solar panels themselves? So if they're bathed in say, half the light intensity, they produce less than 50% of the output? CrackDragon (talk) 08:40, 11 August 2010 (UTC)
Semiconductor behavior can alter with temperature. While not necessarily applicable to Juno's solar cells, an example would be the increase in electrical resistance with decreasing temperature often seen in semiconductors. More resistance = less efficient collection of electricity from the cells. And Juno's going to be colder at Jupiter than a satellite in Earth orbit. 147.160.136.10 (talk) 11:51, 13 September 2010 (UTC)
Performance specifications of Juno solar panels: At 1 A.U = 15,000 Watts. At Jupiter Orbital Insertion (Aug 2016) = 486 watts. At End-Of-Mission (Oct 2017) = 428 Watts. Factors affecting power output include some non-lineararity as light intensity falls, low temperatures, variations in Jupiters distave from Sun over mission duration, aging of cells over 7 year mission, and most importantly, deterioration of solar cells by radiation. Yale s (talk) 08:28, 5 October 2010 (UTC)
Yale s said most of it, but Just want to point out, that many semiconductors have less resistance at colder temperatures, thus the reason super cooling a CPU enables it to achieve reliable higher speeds. —Preceding unsigned comment added by Firegryphon (talk • contribs) 03:52, 20 October 2010 (UTC)
I think you're mistaken; conductors perform better at cold temperatures, but semiconductors suffer as there are fewer charge carriers, increasing resistance to the point where they all "freeze-out", turning the material into an insulator. I believe the rationale behind cooling microprocessors (besides preventing thermal heat damage) is to allow the transistors (MOSFETs) to actually shut off (have enough resistance) versus becoming uncontrollable (always on). Just my guess though. -- atropos235 ✄ (blah blah, my past) 14:47, 2 November 2010 (UTC)

Other periods without sunlight?

Section Solar panels: "The solar panels will remain in sunlight continuously from launch through to the end of the mission, except for short periods during the operation of the main engine." Is that the only time it is not in sunlight? How can it avoid coming into Jupiter's shadow while in orbit around Jupiter?--Mortense (talk) 12:37, 6 August 2011 (UTC)

It is a polar orbit ~ imagine the hands of a watch circling while facing the sun and that their axel is Jupiter. Cheers, BatteryIncluded (talk) 20:14, 6 August 2011 (UTC)

Travel speed too low?

In section Mission summary: "will travel faster ... (4.4 km/s) to reach the planet." This seems a little too low. The orbital speed of Jupiter is 13.07 km/s and the orbital speed of Earth is 29.78 km/s. I would expect the average travel speed to be above 13 km/s. If the 4.4 km/s is the minimum distance between Earth and Jupiter divided by the travel time I think it is misleading. What should it be? --Mortense (talk) 11:16, 6 August 2011 (UTC)

I suppose that is the speed required to intercept Jupiter, not chase it along. Cheers, BatteryIncluded (talk) 20:08, 6 August 2011 (UTC)
It is clear from the orbital manueavers that the slowest speed is when approaching Jupiter, chasing it. So it never travels slower than 13 km/s.— Preceding unsigned comment added by Mortense (talk • contribs)
I removed it.--Patrick (talk) 22:19, 8 August 2011 (UTC)

Explanation for 2012 Earth Flyby

Most readers including myself will be confused as to why a spacecraft headed to Jupiter will undergo an earth flyby two full years after leaving the earth. The actual path of the Juno probe ought to be included, so as to explain the earth flyby. Also, any other details about the flight path would interest readers. Douglas.hawkes (talk) 13:17, 6 August 2011 (UTC)

I've added File:Juno's interplanetary trajectory.jpg. You can see that Juno's current orbit isn't big enough to reach Jupiter. Not sure what "DSMs" means; 'Deep Space Maneuvers'?
—WWoods (talk) 16:58, 6 August 2011 (UTC)
It took me a while to work out "EFB" = "Earth Flyby" and "JOI" = Jupiter Orbital Insertion...I think. These could do with explaining in the image comments too. NinjaKid (talk) 12:18, 9 August 2011 (UTC)
You guys are right in all accounts, and the Deep space maneuvers (DSM) are scheduled for 30/August/2011 and 3/Sept/2012. BatteryIncluded (talk) 13:39, 9 August 2011 (UTC)

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Created Cost section

I have created a "cost" section and moved the cost details out of the introduction where they interrupted the flow of the description of the subject.109.154.74.121 (talk) 08:22, 31 August 2011 (UTC)

Europa?

With a mission this size will there be any analysis of Jupiters moon Europa and its saltwater Oceans? 69.171.160.77 (talk) 23:45, 13 October 2011 (UTC)

That question has come up in press conferences and the answer is no. This mission is specific to the planet and no moons will be targeted. There might be some imaging but no significant science will come from this mission related to the moons. The spacecraft will be sacrificed at the end of the mission specifically to prevent contamination of interesting moons such as Europa.--RadioFan (talk) 01:21, 5 February 2012 (UTC)

Mission duration: 1 Earth year

NASA is spending $700 million on this project, and it's only lasting one year? Why not ten or more? Our weather satellites are designed to last decades. Why can't we expect similar results from Juno? Someone at NASA should get fired over this blunder.173.58.64.64 (talk) —Preceding undated comment added 16:53, 27 August 2010 (UTC).

Before firing someone at NASA, it'd probably be worthwhile to note many NASA deep space missions have a short period of performance at launch. The dramatic ones get funding extensions. For example, the Mars Exploration Rover program cost $840 million to design, build, and deliver 2 rovers to Mars and operate them for 90 days. The multi-year operational extensions beyond 90 days have, to date, cost about $140 million. http://en.wikipedia.org/wiki/Mars_Exploration_Rover Operating deep space probes is also rather more expensive than operating a weather satellite; weather satellites have lots of paying customers and need relatively simple communication hardware on the ground, while operating Juno needs time on the Deep Space Network and the support of expensive specialists. If NASA gets some dramatic wins and public interest with Juno's first year, it probably will no trouble taking your logic to Congress and saying, "We've got $700 million orbiting Jupiter that's got thousands of miles left on its tires. Give us $100 million and we can operate it for 5 more years and show the taxpayers we're getting dramatically better bang for their buck." 147.160.136.10 (talk) 12:06, 13 September 2010 (UTC)
This is not supposed to be a discussion forum, but you must understand that Earth satellites operate within the protecting envelope of the magnetosphere. In addition to the solar radiation, Juno will be exposed to large amounts of radiation emited by Jupiter.--BatteryIncluded (talk) 13:39, 15 September 2010 (UTC)
The probe will be exposed to extremely high radiation levels and would not be expected to survive for extended time. The craft will be de-orbited (as was Galileo) while it is still manageable, in order to avoid a future collision and contamination of one of Jupiter's moons. Yale s (talk) 08:35, 5 October 2010 (UTC)
This should probably be explained in the article. The article, as well as NASA's own website about the mission, only mentions that it will be deorbited after the 33rd orbit, without any explanation as to why that is. I wondered if it was to take measurements of the atmosphere directly, which would be interesting if possible to pull off. But to avoid contaminating the moons due to the spacecraft becoming uncontrollable also makes sense. Is there a reference for that, or just an educated guess? Harperska (talk) 01:19, 23 October 2012 (UTC)
A somewhat macabre joke in the flight software group was that if you were thrown out of the spacecraft in Jupiter's magnetic field without a space suit, you would die of radiation before you asphyxiated.Freakdog (talk) 08:32, 17 April 2012 (UTC)

Billions?

The change (with summary "billions is ambiguous" from billions to millions in the article around distance measurements "1.74 billion miles (2.8 billion kilometers)" to "1,740 million miles (2,800 million kilometers)" has been reverted twice now. Before this is changed again, there should be consensus established here.

  • Against given the launch date of this mission there should be no concerns that anything but the short scale definition of 1 million is being used here. All references use the billion figure. 1.74 billion is more readable that 1,740 million.--RadioFan (talk) 01:14, 5 February 2012 (UTC)
  • Against. USA mission in use of North American short scale numbers. BatteryIncluded (talk) 03:05, 5 February 2012 (UTC)
Comment: An IP editor changed this to billions from the original text of millions, I merely reverted the change back to the original. Billions is ambiguous and there is no description in the article about how billions is supposed to be interpreted. Changing to Billions creates confusion. HumphreyW (talk)
Comment the change from millions to billions came in this edit by Wraithful not an IP editor (though I'm not sure why it would matter if an IP editor made the change, they are welcome to edit as well). There might be some ambiguity if this mission launched in 1911 from Europe but it didn't, it launched in 2011 by an agency that has always used the short scale. There has been global agreement on what a "billion" and beyond is for almost 30 years.--RadioFan (talk) 12:42, 5 February 2012 (UTC)
Comment: It's less important which form of numeric scale you use and far more important that a "translation" accompany it so that people from countries using the scale not used in the article understand what is meant. Please keep in mind that either way there are millions of people that use either form, so therefore being considerate to whoever's form of numeric terminology gets scrapped (by providing a clear translation note) is paramount. 98.173.62.28 (talk) 23:24, 8 June 2012 (UTC)
Comment: This is the English Wikipedia, and English uses short scale.101.166.150.53 (talk) 06:01, 3 January 2013 (UTC)

Jupiter's inner moons

Will Juno image Jupiter's inner moons Metis, Adrastea, Amalthea, and Thebe? --JorisvS (talk) 11:06, 20 February 2013 (UTC)

Scientific objectives

I came to this article, due to a discussion here. Looking at last bullet of the "Scientific objectives" section, I'd suggest reviewing that. Measuring general relativistic effects were not likely an objective of this mission. A few papers, mainly by a single researcher (re: the discussion I linked to), are written about results after the fact from Juno, but I found no evidence of that being an "objective", even from the NASA website, and the U of Wisconsin "Objectives" site listed on this article. Cheers, AstroCog (talk) 00:45, 23 October 2013 (UTC)

You are correct. It seems not a declared objective but "possibly a new test of general relativity effects connected with the Jovian rotation." Source: Iorio, L. "A possible new test of general relativity with Juno". Classical and Quantum Gravity. 30 (18). doi:10.1088/0264-9381/30/19/195011. Retrieved 2014-01-21.. --BatteryIncluded (talk) 23:49, 21 January 2014 (UTC)

Close to the poles

Several wikipedia articles on Juno repeat the claim that Juno's elliptical polar orbit takes it close to the poles. Is this true? The periapsis is at 4300 km, but none of the citations explicitly state that the periapsis is near the poles, and the diagram suggests the periapsis is near the equator. Some digging http://www.trylam.com/files/AIAA_2008-7369_Launch_Period_Development_for_the_Juno_Mission_to_Jupiter.pdf suggests that the perijove starts at latitude 3 deg increasing by 0.9 deg each orbit over 33 orbits. Eyeballing the 33rd orbit gets me a minimum pole-ellipse distance of maybe 25K Km?

Willhsmit (talk) 02:26, 19 June 2015 (UTC)

I am not familiar with the terminology; The mission's home page calls it a polar orbit: [1]. The text will appear at the end of the short video.
Cheers, BatteryIncluded (talk) 15:19, 19 June 2015 (UTC)

References

New Horizons twice in See Also

New Horizons is listed twice in See Also - can one of these be eliminated? Bubba73 You talkin' to me? 23:32, 21 June 2015 (UTC)

Actually, it is already linked in the body of the article, so should not even be in the See also section at all. I've cleaned it up. --JorisvS (talk) 09:16, 22 June 2015 (UTC)

GA Review

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Reviewing
This review is transcluded from Talk:Juno (spacecraft)/GA1. The edit link for this section can be used to add comments to the review.

Reviewer: Cirt (talk · contribs) 05:20, 23 October 2015 (UTC)


I will review this article. — Cirt (talk) 05:20, 23 October 2015 (UTC)

Stability assessment

  1. Upon my inspection, article edit history is stable going back over one month.
  2. Same with article's talk page.

No issues here. Next, on to Image review.

— Cirt (talk) 05:38, 23 October 2015 (UTC)

Image review

There are a lot of images used in the article. All hosted on Wikimedia Commons. Upon my inspection of all of their image pages, only two minor issues to please address:

  1. File:Juno lego.jpg = please format with commons:Template:Information and fill out all fields in template.
  2. File:Galileo plaque.jpg = please format with commons:Template:Information and fill out all fields in template.

Please address above, and then comment, below, when done with that.

Thank you,

— Cirt (talk) 05:47, 23 October 2015 (UTC)

@Cirt: Done! Huritisho 06:00, 23 October 2015 (UTC)
Thanks, looks much better. Just a note to say that I did review and inspect all image pages. Image review passes here. Next, on to rest of review. — Cirt (talk) 06:03, 23 October 2015 (UTC)

Note on GA Nominator

Note: Huritisho has been confirmed and blocked as a sock of Tetra quark (talk · contribs), per investigation Wikipedia:Sockpuppet investigations/Tetra quark. I'd no idea that process was going on, and it's unfortunate, but relevant to note here. — Cirt (talk) 17:50, 23 October 2015 (UTC)

Failed "good article" nomination

This article has failed its Good article nomination. This is how the article, as of October 23, 2015, compares against the six good article criteria:

1. Well written?:
  1. Copyvio Detector = https://tools.wmflabs.org/copyvios/?lang=en&project=wikipedia&title=Juno+%28spacecraft%29&oldid=&action=search&use_engine=0&use_links=1 = shows a couple problems that could be addressed by trimming quotes down or paraphrasing to get all values below 30 percent confidence.
  2. Per WP:LEAD, lede section is a bit short, especially last paragraph of two-sentence-long-paragraph. Suggest lede size of three paragraphs at least, with 4-5 sentences each, or 4 paragraphs with 4 sentences each.
2. Verifiable?:
  1. Checklinks tool -- http://dispenser.homenet.org/~dispenser/cgi-bin/webchecklinks.py?page=Juno_%28spacecraft%29 -- shows several links problems. Problem = defined as any value other than "200" or "0", or "200" with a comment next to it is also bad. These can be fixed by archiving with Wayback Machine by Internet Archive using fields archiveurl and archivedate with WP:CIT templates.
  2. In August 2016, the spacecraft will perform an orbit insertion burn to slow the spacecraft enough to allow capture into a 14-day polar orbit. = unsourced sentence.
  3. The vehicle coasted for approximately 30 minutes, and then the Centaur was re-ignited for a second firing of 9 minutes, putting the spacecraft on an Earth escape trajectory. = unsourced sentence.
  4. Each orbit takes 14 days and the spacecraft is expected to complete 37 orbits until the end of the mission. = unsourced sentence.
  5. In comparative terms, Juno will receive much lower levels of radiation than the Galileo orbiter. = unsourced sentence.
  6. Scientific instruments best to have cites after each entry in the "Description" box.
  7. as well as advances made in both solar-cell technology and efficiency over the past several decades, makes it economically preferable to use solar panels of practical size to provide power at a distance of 5 AU from the Sun. = unsourced sentence.
  8. The command and data processing of the Juno spacecraft includes a flight computer capable of providing ~50 Mbit/s of instrument throughput. Gravity science subsystems use the X-band and Ka-band doppler tracking and autoranging. = unsourced sentence.
  9. Several broken cites.
  10. Not sure why some cites have redlink to page Juno (sonde spatiale).
  11. Recommend standardizing all citations with WP:CIT templates.
  12. Strongly suggest moving to Notes/References sect like at The General in His Labyrinth.
3. Broad in coverage?: Missing: Article is missing a Commentary or Analysis section, with secondary sources describing the impact or potential impact this could have on the scientific community and wider society as a whole.
4. Neutral point of view?: Neutral tone and matter-of-fact presentation, no issues here.
5. Stable?: See above, no issues here.
6. Images?: See above, no issues here.

Huritisho has been confirmed and blocked as a sock of Tetra quark (talk · contribs), per investigation Wikipedia:Sockpuppet investigations/Tetra quark. I'd no idea that process was going on, and it's unfortunate, but relevant to note here. Hopefully other editors will find above notes helpful, in the future.

When these issues are addressed, the article can be renominated. If you feel that this review is in error, feel free to have it reassessed. Thank you for your work so far.— — Cirt (talk) 23:11, 23 October 2015 (UTC)

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Juno is not an acronym

I removed JUpiter Near-polar Orbiter as an explanation for what Juno stands for. I've only been able to find this backronym in a single NASA document defining acronyms for missions. This description appears nowhere in any mission documents. As the 3rd paragraph explains, the mission was named for the character from roman mythology.--RadioFan (talk) 18:57, 20 June 2016 (UTC)

These articles mention the acronym as well. —Torchiest talkedits 22:54, 20 June 2016 (UTC)
I suspect it's most likely actually a backronym, though we'd need a source that says so. --JorisvS (talk) 18:47, 21 June 2016 (UTC)
I suspect Wikipedia is the source for these articles, not NASA, SwRI, ULA or any other partner in this mission. The only NASA sources for this backronym are an acronym list from science mission directorate mission planning documents. It appears nowhere else. Not in any documents or webpages produced by the mission team, not in any academic papers which reference the mission, not in any other NASA publications, not in the Launch Press Kit, nor the Orbit Insertion Press Kit. This backronym does not belong in the article lead. It has been moved to the paragraph on mission naming.--RadioFan (talk) 00:21, 23 June 2016 (UTC)

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Spacecraft "bus", and Juno's relationship to Jupiter

Two unrelated points:

  • At one of the points at which the gods' relationship is introduced, it should probably be mentioned that Juno and Jupiter were siblings as well as husband and wife, because that's actually pretty interesting.
  • The image caption references "spacecraft bus" but by the definition in the linked article Juno would seem to be a one-off, rather than a bus-based spacecraft. If "bus" doesn't imply commonality across craft, that article needs serious rework. If Juno does share commonality with some other craft in the works, this article ought to tell us which one.

I won't muck with the article while it's protected, but I'll make some edits on these points if nobody gets to it in a few days—or lets me know why to leave it as-is. Sharkford (talk) 20:44, 5 July 2016 (UTC)

Dubious fuel mass

I tagged the JOI fuel mass claim in section Insertion into Jupiter's orbit because 7900 kg is a surprisingly large mass for a 3600 kg spacecraft to possess, and also because I feel businessinsider is a poor source ([2] is the original source) for science topics and we should really use a cite that in turn gives its own sources. -84user (talk) 19:25, 4 July 2016 (UTC)

  • This JPL press-kit contradicts businessinser source with these details:
    Weight: 7,992 pounds (3,625 kilograms) total at launch, consisting of 3,513 pounds (1,593 kilograms) of spacecraft, 2,821 pounds (1,280 kilograms) of fuel and 1,658 pounds (752 kilograms) of oxidizer.
  • -84user (talk) 19:38, 4 July 2016 (UTC)
Excellent point about the fuel mass. I contacted the author of the article for clarification. GPS Pilot (talk) 19:59, 4 July 2016 (UTC)

This edit removed the erroneous mass that I tagged above, so I'm satisfied and this section can be archived at the next opportunity. However, the new delta velocity claim has now been tagged as dubious (not by me), so I'm creating a new Talk page section below at Juno (spacecraft)#Dubious reduction in velocity. -84user (talk) 23:25, 5 July 2016 (UTC)

Semi-protected edit request on 6 July 2016

The procedure will take 5.5 days, during which the spacecraft will end communications and "descent" into "the" Jupiter's atmosphere. Should be changed to ....descend into Jupiter's atmosphere.

142.90.105.23 (talk) 00:17, 6 July 2016 (UTC)

Done — Andy W. (talk · ctb) 00:33, 6 July 2016 (UTC)

Semi-protected edit request on 6 July 2016

Re INSERTION TO JUPITER'S ORBIT

There is an error in that section. The 2102 second burn has reduced the velocity _BY_ 542 m/s, not _TO_ 542 m/s. This is two orders of magnitude mistake given the 74,000 m/s approach velocity.

108.7.74.250 (talk) 03:06, 6 July 2016 (UTC)

Done by Karn. – nyuszika7h (talk) 07:50, 6 July 2016 (UTC)

Arrival date contradiction

There are three well-cited dates listed in the article: August 2016, in the infobox; July 2016, in the lead sentence and mission summary section; and October 2016, in the Timeline section. I'm not sure which one of these should actually be used, since they all have reputable citations. AndreniW (talk) 19:30, 13 June 2015 (UTC)

The August date was from a NASA publication 10 years before the launch, so I would not count on it - something could have changed. http://juno.wisc.edu/mission.html gives the October date - it was published 3 years before launch. I think the other date was "about July 4, 2016", but that might be when it is expected to start doing observations. Bubba73 You talkin' to me? 19:49, 13 June 2015 (UTC)
Well, this says July 4, 2016 so I would go by it. Bubba73 You talkin' to me? 20:38, 13 June 2015 (UTC)
As I see it the August date is not the current one. ″Juno is scheduled to arrive at Jupiter on July 4, 2016 (Pacific Daylight Time). Once it settles into orbit, the spacecraft will brave the hazards of Jupiter's intense radiation when it repeatedly approaches within a few thousand miles, or kilometers, of the cloud tops to collect its data." [1] This information is relatively fresh. I propose that the references to August 2016 should be changed to "about 4 July 2016" or even "July 2014". I nobody disagrees I could change it. Rudy235 (talk) 11:08, 25 September 2015 (UTC)

References

  1. ^ http://www.missionjuno.swri.edu/news/juno_status_07072015

July 2016

Was it 'late'? per this edit which changed 4 to 5 July, though it also adds UTC. What is the standard date/time usage for spaceflight? 220 of Borg 04:32, 5 July 2016 (UTC)
UTC. Always UTC. So anything that says "July 4" should specify a timezone (and give a UTC offset). Kolbasz (talk) 09:08, 6 July 2016 (UTC)
I thought so. Right now the page has conflicting dates in lead and body. I think it should be July 4. "At 11:53 p.m., Eastern time, a signal from the spacecraft announced the end of a 35-minute engine burn that left it in the grip of its desired orbit around Jupiter". So it appears it 'arrived' shortly before midnight, but that is Eastern time which I think is currently UTC−05:00. I think we need a source that clearly says "Juno arrives at XX:XX (UTC)". There is can edit request related to this at the (current) bottom of the page. 220 of Borg 14:32, 6 July 2016 (UTC)

Tone-fault signalling

The phrase "tone-fault signalling" seems to appear only in this article and mirrors. It is unexplained. Can we replace the first part of this sentence by "Juno supports in-band signaling for fault reporting in cruise-mode operations, but..." or something even better? --Mirokado (talk) 21:14, 5 July 2016 (UTC)

@Mirokado: I recall that tones were used during the decent and landing of the Mars Exploration Rovers.[3][4] There's a NASA page that features a person who "gets to use the software she helped develop to listen to the tones that are broadcast during the entry, descent and landing phase of most of JPL's landers launched since 1999. She will also be listening to tones from the Juno spacecraft when it arrives at Jupiter in 2016."[5] This Juno mission press release mentions that the tone signalling system was tested during the Earth flyby between Aug. 30, 2012, and Sept. 14, 2012. --Marc Kupper|talk 23:32, 5 July 2016 (UTC)
Thank you @Marc Kupper: for the detailed response. I was motivated to look further myself and found a definition for "tones" on the Key Terms page of the Mission Juno site. It looks as if they are not only used for fault indication, indeed as the only status indications for three essential operations. I will replace the phrase and add a reference to the definition. I think the rest of the sentence also needs further consideration, so further changes from others will be welcome. Again thanks for your response. --Mirokado (talk) 21:10, 6 July 2016 (UTC)

Dubious reduction in velocity

I'm creating this section for discussion on the delta-velocity claim in the "Insertion into Jupiter's orbit" section that has been tagged as dubious. I'm looking for better sources now, but the given reason was: "spacecraft velocity was 74 km/s before the burn, and is now something like 18 km/s; the 540 m/s velocity reduction seems way off". -84user (talk) 23:25, 5 July 2016 (UTC)

@84user: Have you seen http://www.jpl.nasa.gov/edu/pdfs/piday2016_answers.pdf ? It's the answer sheet for this page but explains the 540 m/s Δv. --Marc Kupper|talk 23:36, 5 July 2016 (UTC)

That's a good answer to help better understand delta-v as well. The article's dubious tag has since been removed, I trust the tagger is happy with the answer above. Additional sources: [6] and [7]. Also, for what it's worth one can get space probe data from NASA's HORIZONS web-interface, a cropped example follows: 

    MAJOR EVENTS 
 Launch        : Aug 5,  2011 16:25 UTC 
 Separation    : Aug 5,  2011 17:24:56.12 UTC
 DSM-1         : Aug 30, 2012 22:29       UTC (344.95 m/s)
 DSM-2         : Sep 3,  2012 22:29       UTC (387.77 m/s)
 Shadow entry  : Oct 9,  2013 19:19:36    UTC (alt.= 7069 km, umbral)
 Earth Flyby   : Oct 9,  2013 19:21:25    UTC (alt.= 558.848) 
                  (lat=-34.170 deg,E.long= 34.008 deg
 Shadow exit   : Oct 9,  2013 19:39:01    UTC (alt.= 14896 km, umbral)
 Arrive Jupiter: Jul 5,  2016 02:30 UTC   (JOI to 53.5-day capture orbit, 
                                           delta-v= 541.7 m/s)
 Period Reduction Maneuver:
                 Oct 19, 2016             (Target 14-day orbit period,
                                           delta-v= 395.2 m/s)
 End of mission: Feb 20, 2018 11:40 UTC   (Jupiter impact, 700 km below
                                           1-bar atmospheric pressure level)

... 

* Total delta-V budget: 2107 m/s (~1852 m/s on bi-prop; remainder on RCS)

-84user (talk) 01:43, 6 July 2016 (UTC)

Yes. The orbit capture burn wasn't instantaneous, and it was performed around perijove when Juno's velocity was already changing rapidly as it fell into and then climbed back out of Jupiter's gravity well. For this reason, delta-Vs are always specified as the change in velocity that would occur were the spacecraft far from any massive body. This number is fully determined by the effective exhaust velocity of the rocket engine and the total spacecraft masses before and after the burn. See also Tsiolkovsky rocket equation and Oberth effect. User:Karn Karn (talk) 04:33, 7 July 2016 (UTC)

Radiation and solar panels

It appears radiation will damage the solar panels. It is expected this will lead to progressively less power to the spacecraft over the mission, thus shortening the length of the mission. It would be interesting to know why the designers chose this vs. a nuclear powered craft which could last longer. -- GreenC 14:42, 5 July 2016 (UTC)

The little plutonium that is left will be used on the next Mars rover. BatteryIncluded (talk) 14:45, 5 July 2016 (UTC)
God bless you for trying, but your response is pretty useless. To respond to the OP, that design would have added cost to the project. The orbiter's mission was always to last approximately as long as it was designed for, and it will be destroyed after 'mission accomplished.' 98.67.185.116 (talk) 02:06, 8 July 2016 (UTC)

Semi-protected edit request on 6 July 2016

Please change "On July 5, 2016, the spacecraft performed an orbit insertion burn to slow it enough to allow capture." to "On July 4, 2016, EDT, the spacecraft performed an orbit insertion burn to slow it enough to allow capture."

The current article incorrectly states that the orbit insertion occurred on July 5th. It in fact occurred on July 4th (start to finish - finish was 11:53 p.m. EDT). Since mission control was in EDT and all press releases given in EDT, there should be no debate as to it indeed being July 4th.

This can be confirmed by NASA's official press release, found all over but here is a direct link to one: https://www.nasa.gov/press-release/nasas-juno-spacecraft-in-orbit-around-mighty-jupiter

"....Juno spacecraft successfully entered Jupiter’s orbit during a 35-minute engine burn. Confirmation that the burn had completed was received on Earth at 8:53 p.m. PDT (11:53 p.m. EDT) Monday, July 4."

Filsmith (talk) 13:22, 6 July 2016 (UTC)

 Not done. Although it happened on July 4 Eastern USA time, the convention in space missions at Wikipedia has always been to record the Coordinated Universal Time. Thanks, BatteryIncluded (talk) 15:06, 6 July 2016 (UTC)

I agree with this -- the US has four continental time zones, and major space missions are controlled from NASA centers in three of them. To minimize confusion, UTC is the way to go. User:Karn Karn (talk) 04:24, 7 July 2016 (UTC)

For all 4 times zones it would still be July 4th. 11 something eastern to 8 something western time. I cant remember exact time. 11:53 or so. If its says July 5th than thats a lie. Telling people false information. They'll think Europe launched this probe. The date is also important since it arrived on July 4th Independence Day. Now the English and European users that edit this are trying to steal that from us with a lie. — Preceding unsigned comment added by 24.44.69.250 (talk) 01:47, 28 August 2016 (UTC)

I'm sorry that you think only the U.S. has time zones, but that is incorrect. It was launched on 5 July 2016 in Coordinated Universal Time. It isn't false information. It is simply another time zone in a world with 24 of them. No one is going to think that Europe launched Juno based on a time, when the lead paragraph clearly states that NASA launched it. It is completely immaterial to to science that it launched on 4 July, and is only of political concern. Wow. — Huntster (t @ c) 06:45, 28 August 2016 (UTC)

Infobox perijove

Shouldn't it be 4200 km plus Jupiter's radius? Th4n3r (talk) 20:19, 15 December 2016 (UTC)

Probably. It's a common practice to leave out the planet's radius, but that's generally stated as an altitude. I just changed it to say ``4200 km altitude (75.6 thousand kilometer radius). Fcrary (talk) 21:47, 23 December 2016 (UTC)

Juno mission details (orbits, time-lines) need to be edited due mechanical issues

Why isin't juno's planned orbits and mission duration re-worded to indicate past-tense, because clearly it will not perform the intended number of orbits during the intended mission plan.

This article needs to be updated to reflect (as best as is known currently) what the mission profile looks like (number of orbits and duration extension - if any).

Also- need to mention the possibility of not being able to end the mission as planned if propulsion system does not function as intended. — Preceding unsigned comment added by 70.30.80.84 (talk) 00:43, 3 January 2017 (UTC)

I'm not aware of any citable references to the current plan. There have been some statements that they are working on it, and won't reduce the orbital period yet. But I don't think there is anything official about whether or not they will ever go to 14 day orbits. Since we're supposed to have references, I'm not sure how to handle that.

I also haven't heard anything about the end-of-mission plans being affected. Spacecraft can and have made small maneuvers using their attitude control thrusters, so a decision not to use the main engines does not automatically affect the deorbit maneuver. I don't think we should add anything about this unless we have a reference.

Fcrary (talk) 22:54, 6 January 2017 (UTC)

Updates should be made when a reliable source per WP:verifibility is available. Cheers! Skyraider1 (talk) 00:42, 7 January 2017 (UTC)

I've updated the entry based on a JPL press release dated Dec 12. That's all the citable information I can find at this point. Fcrary (talk) 01:39, 16 January 2017 (UTC)

Juno's orbit

Newest NASA press release (Feb 17, 2017) states that the Juno spacecraft will stay in its current 53-day orbit for the remainder of the mission, thus probably extending the life of the spacecraft and raising possibilities for an extended mission after the conclusion of its main mission around July 2018 (now 12 orbits total). Please change sections appropriately. [1] 2A02:587:5C16:5D00:1C98:CBA0:FB42:4F0F (talk) 02:41, 3 March 2017 (UTC)

First results

A Whole New Jupiter: First Science Results from NASA’s Juno Mission

I wonder if this type of organism could exist on Jupiter? https://en.m.wikipedia.org/wiki/Hydrogenosome 

Sugarpixie4 (talk) 17:28, 28 May 2017 (UTC)

End of mission data

109.252.87.4 just made an edit listing the end of mission as 2021. The information on that isn't clear. Current approved funding ends in 2018 and an extension to 2021 will require approval from NASA headquarters. That decision is due out later this year, but hasn't happened yet. (OPAG presentation by Neiber and text of draft participating scientist AO.)

There are a couple other places where the article gives a 2018 end of mission (EOM) date, and one place giving 5.5 days between EOM maneuver and impact; that was true of the original 11 or 14 day orbits, not the current 54 day orbits.

I suggest changing everything to 2018 end of funding and, if further funding is approved, end of mission and impact in 2021. If no one objects within a couple days, I'll put in those changes.

(As a quibble, this is based on a primary source, which we aren't supposed to do. The text referenced was written by the project itself, and they have personal opinions on when they would like the mission to end...)

Fcrary (talk) 16:34, 17 September 2017 (UTC)

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Juno mission extended

NASA announced today that they have approved an update to Juno's science operations until July 2021[2]. Details right here (same link to reference).

Please update article accordingly :) 2A02:587:5C1A:7900:135:97C0:840:9C06 (talk) 20:47, 7 June 2018 (UTC)

 Done, Thank you for the heads up. Rowan Forest (talk) 01:50, 8 June 2018 (UTC)

  1. ^ https://www.nasa.gov/press-release/nasa-s-juno-mission-to-remain-in-current-orbit-at-jupiter
  2. ^ https://www.nasa.gov/feature/nasa-re-plans-juno-s-jupiter-mission

Add a section on Juno discoveries?

I just reverted a change on lightning detections. It was added under the "Insertion into jovian orbit" section (which makes no sense to me. It was very long and vague about what Juno observed which was different from past missions. But this made me realize we do not have any section devoted to Juno discoveries or results. We should probably add one (including a short mention of the lightning observations.) But there is a long list of new discoveries from Juno, and I'd say lighting isn't near the top... Fcrary (talk) 20:40, 28 November 2018 (UTC)

On the broad question of how deeply a space probe article should go into its scientific accomplishments, I offer no opinion now, but on the specific question of Jovian lightning detection, that was all the work of one instrument, the Microwave Radiometer (Juno). So, I have mentioned the detection in that article. Perhaps others will think it should be expanded upon there, or be more integrated into Atmosphere of Jupiter. Jim.henderson (talk) 16:13, 2 December 2018 (UTC)
Mentioning the lightning detections is fine, and the way you phrased it in the Microwave Radiometer (Juno) reads well. The earlier text in the main Juno article sort of implied the MWR result was a major discovery and previous detections by Galileo and Voyager were unimportant in comparison. What you've put in is a simple statement of the observations, and I like more.
In terms of science accomplishments in the main article, I don't think there is a general standard, but some articles on space missions (e.g. Cassini have lengthy sections on discoveries and results. In the Juno article, there is a section on the mission's science objectives. The mission has made quite a bit of progress on them, as well as additional results like the lightning observations. I think a sentence or three on each would be worth adding (but I'm not going to have a chance for a few weeks...) Fcrary (talk) 20:36, 2 December 2018 (UTC)
Easier to find time for writing about our intentions, than for thinking enough to make the change. Anyway, I put a sentence in the present article and another in the atmosphere one. I figure the one here ought to be expanded into a proper paragraph as results are published. Science work, after all, tends to be slow. My guess is the original attempt was a rehash of a press release (that's what press releases are for) which was the source of the peacockery. Since our thoughtful writers on Jovian atmosphere didn't think the earlier opinions of lightning were important enough to put in that article, I don't see how this revision belongs there, either. Naturally, not having studied the matter, I will not be at all annoyed if they decide I'm wrong about that. Jim.henderson (talk) 03:00, 3 December 2018 (UTC)

Juno as a name rather than an acronym

The article currently states that Juno is an acronym for "Jupiter Near Polar Orbiter." However, the reference for this is extremely weak and this claim contradicts statements by the project itself.

The reference for this is an anonymously written list of mission names and acronyms. It is on a NASA web page, but there is no sign anyone ever reviewed or approved it. It appears to be a second or third hand collection if names, with no citation beyond stating "Science Mission Directorate (SMD) submit; 2-6-08" is a source. This is an extremely weak reference.

All of the statements and press releases have consistently stated that Juno is a name, sometimes discussing the mythological origin. They have never, as far as I can tell, said anything about an acronym. (Note also that the project never writes in in block capitals, as an acronym would be written) In fact, the PI has stated in public presentations that it is just a name, and he did not want to use an acronym for the mission. If I could find a transcript or recording of those talks, this would be easy to clear up. But that was back before launch in 2011, and I can't find anything citable.

Even without that reference, I don't think the statement about an acronym belongs in the article. Given the weakness of the reference to an acronym and the disagreement with multiple, consistent statements from the project that Juno is just a name and doesn't stand for anything, I think we should just go with what the project says. I tried to make that change, but it was reverted. Instead, I've just put in a statement about the source and the consistency of the project's statements that it's a name. Fcrary (talk) 18:31, 22 May 2019 (UTC)

That's fine. I wouldn't have reverted if you had provided a reference or a better explanation. WolfmanSF (talk) 03:47, 23 May 2019 (UTC)

Speed at orbital insertion and original research

It looks like people have found conflicting references on Juno's speed at the start of orbital insertion. Unfortunately, both are wrong. The 130 mph (210 km/hr or 57.8 km/s) is below escape velocity, and Juno was quite definitely coming from outside the Jovian system. But the other number 265 km/hr (73.6 km/s) implies it was going at 45 km/s as it approaches Jupiter. That's also wrong; it was about 6 km/s. I could solve this in about two minutes using publicly-available JPL-provided ephemeris software and data files I've already downloaded. But that would probably be considered original research. Does anyone have a suggestion? Fcrary (talk) 22:28, 1 October 2019 (UTC)

Seems the actual speeds (and related references) are reported as 210,000 km/h (130,000 mph)[1] and 265,000 km/h (165,000 mph)[2] - yes - seems like a discrepancy of some sort - a third newly found reference (possibly related to NASA?) support the 266,000 km/h (165,000 mph)[3] speed - iac - hope this helps in some way - Enjoy! :) Drbogdan (talk) 00:42, 2 October 2019 (UTC)

References

  1. ^ Chang, Kenneth (July 5, 2016). "NASA's Juno Spacecraft Enters Jupiter's Orbit". The New York Times. Retrieved October 2, 2019.
  2. ^ Cofield, Calia (August 24, 2016). "How We Could Visit the Possibly Earth-Like Planet Proxima b". Space.com. Retrieved October 2, 2019.
  3. ^ Staff (2016). "How Fast Can Juno Go?". Southwest Research Institute. Retrieved October 2, 2019.

Jupiter’s third pole in relation to red spot?

Is there a relationship between the raging storm called the red spot and the third pole found on Jupiter? Are the swirling storms at the north and south poles a precursor to the red spot? Do these giant electric tornadoes create a magnetosphere? Longtermthoughts (talk) 06:01, 11 February 2020 (UTC)

Instruments still operational

There are some instruments that had a "limited lifetime" (MWR, JIRAM, JunoCam, any other?). The change in the orbital operations probably affected this expected lifetime. But there is nothing said about their present status, except for the JunoCam (operational in June 2021). Do you have any further information?

Best regards, Santiago Jordá — Preceding unsigned comment added by 88.3.211.218 (talk) 11:47, 27 January 2022 (UTC)

Perijove Dates?

Can we get the dates of the perijoves after #35? Each one to the beginning of 2022 has the date, but only the moon flybys afterwards. Not even the Juno website has the dates. CFLeon (talk) 19:22, 10 April 2022 (UTC)

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