JUNO Orbiter Mated to Mightiest Atlas rocket for Aug. 5 Blastoff to Jupiter

Article Updated: 24 Dec , 2015


In less than one week’s time, NASA’s $1.1 Billion Juno probe will blast off on the most powerful Atlas V rocket ever built and embark on a five year cruise to Jupiter where it will seek to elucidate the mysteries of the birth and evolution of our solar system’s largest planet and how that knowledge applies to the remaining planets.

The stage was set for Juno’s liftoff on August 5 at 11:34 a.m. after the solar-powered spacecraft was mated atop the Atlas V rocket at Space Launch Complex 41 at Cape Canaveral and firmly bolted in place at 10:42 a.m. EDT on July 27.

“We’re about to start our journey to Jupiter to unlock the secrets of the early solar system,” said Scott Bolton, the mission’s principal investigator from the Southwest Research Institute in San Antonio. “After eight years of development, the spacecraft is ready for its important mission.”

Inside the Vertical Integration Facility at Space Launch Complex 41, the Juno spacecraft, enclosed in an Atlas payload fairing, is in position on top of its Atlas launch vehicle. The spacecraft was prepared for launch in the Astrotech Space Operations' payload processing facility in Titusville, Fla. Credit: NASA/Cory Huston

The launch window for Juno extends from Aug. 5 through Aug. 26. The launch time on Aug. 5 opens at 11:34 a.m. EDT and closes at 12:43 p.m. EDT. Juno is the second mission in NASA’s New Frontiers program.

JUNO’s three giant solar panels will unfurl about five minutes after payload separation following the launch, said Jan Chodas, Juno’s project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

The probe will cartwheel through space during its five year trek to Jupiter.

Upon arrival in July 2016, JUNO will fire its braking rockets and go into polar orbit and circle Jupiter 33 times over about one year. The goal is to find out more about the planet’s origins, interior structure and atmosphere, observe the aurora, map the intense magnetic field and investigate the existence of a solid planetary core.

Hoisting Juno inside the payload fairing at Space Launch Complex 41. Credit: NASA/Cory Huston

“Juno will become the first polar orbiting spacecraft at Jupiter. Not only are we over the poles, but we’re getting closer to Jupiter in our orbit than any other spacecraft has gone,” Bolton elaborated at a briefing for reporters at the Kennedy Space Center. “We’re only 5,000 kilometers above the cloud tops and so we’re skimming right over those cloud tops and we’re actually dipping down beneath the radiation belts, which is a very important thing for us. Because those radiation belts at Jupiter are the most hazardous region in the entire solar system other than going right to the sun itself.”

“Jupiter probably formed first. It’s the largest of all the planets and in fact it’s got more material in it than all the rest of the solar system combined. If I took everything in the solar system except the sun, it could all fit inside Jupiter. So we want to know the recipe.”

Watch for my continuing updates and on-site launch coverage of Juno, only the 2nd probe from Earth to ever orbit Jupiter. Galileo was the first.

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13 Responses

  1. HeadAroundU says:

    So we don’t know for sure if it has a core? I can’t really imagine that it doesn’t have it.

    Couldn’t we send there a lander or some impactor? Maybe I want too much, I wanted Curiosity to use dynamite to search for fossils. 😀

    • WaxyMary says:


      Although, I, personally like the idea of ‘fishing’ for fossils with explosives, grin, I think it would not be a very safe thing for the rover to be near.

      The core is indicated by the theory of Jupiter’s origination –a core is required to accumulate the H and He in such great concentrations –which had to be captured early enough to not be blow away with the ignition of our star. The size of the core under the current theory is very small, building up at the beginning from ices and dusts as the proto small sun, or large icy planet, clears its orbit. This still contains the original heat we see as a part of the signature of Jupiter.

      “At the very center of Jupiter is a small (15 Earth masses) rocky core, leftover from the icy dust particles that originally collected in the early solar nebula.” quoted from http://abyss.uoregon.edu/~js/ast121/lectures/lec19.html

      “Gas planets do not have solid surfaces, but rather build-up in pressure and density as one goes deeper towards the core. Different colors represent different depths into Jupiter’s atmosphere. The colors (reds, browns, yellows, oranges) are due to subtle chemical reactions involving sulfur. Whites and blues are due to CO2 and H2O ices.” quoted, ibid.

      “Jupiter’s interior consists mostly of hydrogen and helium. These elements are gaseous at the top of Jupiter’s atmosphere down to several thousand kilometers. At this point, the pressures and temperatures compress these gases into a liquid state.” quoted, ibid.

      Much is now known of the fluid dynamics of the dense gases and gaseous compounds comprising the outer layers of the atmosphere. However, the zones, belts, and bands seemingly indicate a solid crust somewhere below the cloud tops rather than having no sheer zone or just the increasingly dense fluid (sloppy, floppy, spongy compressed) sheer zone.

      “On the Earth, the energy to power our storm systems comes from sunlight. Jupiter is too far from the Sun and receives very little energy. The energy needed to power all the turbulence in Jupiter’s atmosphere comes from heat released from the planet’s core.” quoted, ibid.

      Additionally, the impact of SL9 fragments seemingly indicate a solid crust. The rebound after that impact brought up traces of metals in greater amounts and ratios than those comprising what we expected from the impactor alone. This rebound was a faster ‘return’ than would be expected from a solid core very deep below fluid gases and metallic hydrogen layers. The return was not a dense fluid splash expanding into the lesser pressures as would be expected from SL9 impacting the fluid layer nor was it just the after-image of the upper gases aerobraking and tearing the fragments, burning them, as we see in our oxygen rich protective envelope. That type of combustion would require some oxidizer before the impactor reached the deeper layers and would give off a different signature.

      I am thinking that there might be a solid crust, not just a core. We’ll see or learn more soon enough I guess. There is little known theory or hypotheses speculated about all of this, so I. too, am waiting for further data and probes.


      • Anonymous says:

        This is the first I’ve heard of a solid crust. Do you have a link to more information on this hypothesis?

      • WaxyMary says:


        There is only the inferred points as above, the impact of SL9 was filmed, so to speak, check yourself on the rebound timing and spectrum. The expected boundary layers for sheer forces all imply or require a solid surface rather than a viscous surface, as it is much easier to do the math for a solid surface.

        I hope to have data as we all discover more with Juno over the next year of operations.

        I will see if I can dig up a few links with the speculations and thoughts I have outlined but these are folks who will not publish without facts and might not have these ‘memos’ online for all to see. I just happened to be present when a few of them were thinking out loud, then later, reading from their conceptualizations notes. That was many years ago for the first few ‘memos’. A lot of thoughts crystallized with SL9’s multiple impactors heaving a rebound so fast.


      • Torbjörn Larsson says:

        Thanks, a good text on giants I would think.

        As for Jupiter impact signatures, it bears to look at the the current hypothesis:

        “As well as these molecules, emission from heavy atoms such as iron, magnesium and silicon was detected, with abundances consistent with what would be found in a cometary nucleus.”

        This is a variant of null hypothesis, in that the detected heavy atoms is predicted by the present impactor. So there is no such signature left to predict with a Jupiter model.

        Moreover later impact have not originated these signatures at all IIRC, which may be a problem for a Jupiter contribution but not for impactor traces. In the latter case fragmentation and pressure differential heating would happen on many depths and time scales.

    • Torbjörn Larsson says:

      The giants have no real solid surface, as the pressure increases to high levels:

      “Jupiter is thought to consist of a dense core with a mixture of elements, a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen.[30] Beyond this basic outline, there is still considerable uncertainty. The core is often described as rocky, but its detailed composition is unknown, as are the properties of materials at the temperatures and pressures of those depths […] Physically, there is no clear boundary—gas smoothly becomes hotter and denser as one descends.” [Wikipedia]

      An impactor is out – it would slow down and burn up from the atmosphere compression.

      A lander would be crushed before it gets to anything interesting I would think: “At the phase transition region where hydrogen—heated beyond its critical point—becomes metallic, it is believed the temperature is 10,000 K and the pressure is 200 GPa.”*

      Crush or burn, tough life for a young lander.

      * As a comparison, the Galileo entry probe did a little bit of both, died of overheating and overpressure, at more moderate ambient:

      “As the probe descended through 150 kilometers of the top layers of the Jovian atmosphere, it collected 58 minutes of data on the local weather. It only stopped transmitting when ambient pressure exceeded 23 atmospheres and temperature reached 153 °C (307 °F)”.

      • Anonymous says:

        Interesting. How far could a probe go if no costs were spared in it’s construction? I imagine one of the obvious limitations would be size and weight for present launchers.

      • Torbjörn Larsson says:

        I don’t know, but we know landers have braved Venus @ 90 atmospheres and ~ 400 – 500 °C for ~ 0.5 h (Venera). I believe NASA (ESA? JAXA?) is trying to improve on that with a modern lander.

  2. zlatko ignjatovic says:

    Two major projects at once elaborate cosmic Russia. This is a new generation of ships and Soyuz principally November cosmic system with Russian carrier rocket-M. The starting ground for him to build in the Far East. From the perspective of possible piloted flights to the moon.

    Decision on the establishment of new industrial and transport of the cosmic system was adopted in 2006. year. For 20 years Russia will be able to win not only the orbit, but the Moon and even Mars. Now Russian rocket engineers designed not only Polyfunctional ship next-generation heavy weight over 20 tons, but the light aircraft for flights to the ICC, said in an interview with Voice of Russia Deputy Head of Federal Agency of cosmic Alexander Lopatin.

    Read more here:

    • Torbjörn Larsson says:

      Wow, that was a hard read! I _think_ I have tracked down the launcher to a Proton-M rocket; same lines, same “OTOH” Cyrillic if you enlarge the picture.

      It suits, they mention the ISS capability, the 20 ton lift capability to that orbit, and the Baikonur launching site. This should then be the Phase III design.

      The news is then replacing “Union”, which is the old Soyuz launcher. And the ISS/Moon plans.

      Thanks for the update!

      At a guess the chosen N2H4/UDMH fuel would give more launch flexibility (no LOX) than presumably cheaper and relatively simple RP1/LOX, but it must be a difficult choice.* Man-rating the Proton would be good.
      * I thought the stated idea was to get away from the aggressive (?), toxic and costly hypergolic fuels. Alas.

      • Anonymous says:

        Actually, the best Venera probes got into the 100-minute range. Even then the transmissions mostly ended because the relays moved out of range – transmitting straight to Earth wasn’t possible. By the time they ended their efforts they had developed a large amount of gear that worked “natively” in the Venerean surface conditions.

        As such a modern lander would no doubt try to last for tens of hours or even indefinitely.

  3. Anonymous says:

    The jovian planets do likely have solid cores. If they did not and it was gas all the way down they would have a significantly smaller radius as gas more readily compresses. Jupiter has a core of about 20 Earth masses (as I recall), which is a small percentage of Jupiter’s mass of around 300 Earth masses. This core is surrounded by a mantle of metallic hydrogen, which composes most of the mass of Jupiter.


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