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B A new quasi-satellite was discovered in April: 2016 HO3

  1. Jun 16, 2016 #1

    OmCheeto

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    From a spreadsheet I developed during the Ceres mission, I've calculated that the Hubble Space Telescope would barely be able to see it, with a resolution of only 0.026 pixels.
    For comparison:
    Object _____________Pixels
    2016 HO3__________0.026
    Pluto_______________2.1
    Ceres______________18
    Andromeda__284,000

    It has a diameter of between 40 and 100 meters.
    Maximum distance from Earth: 39 million km (100 times the distance to the moon)
    Minimum distance from Earth: 14 million km (38 times the distance to the moon)

    I used the minimum distance, and a diameter of 70 meters, for my Hubble resolution calculation.

     
  2. jcsd
  3. Jun 16, 2016 #2

    mfb

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    Hubble sees it as point-like object, but it is bright enough to be easily visible, at ~1/10 the brightness of Pluto (order of magnitude).
     
  4. Jun 16, 2016 #3

    tony873004

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  5. Jun 16, 2016 #4

    OmCheeto

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    wow....
    I used to be a prolific coder back in the '80s, so I can appreciate a work of art.
    Things sure have progressed since "Celestial Basic". :oldtongue:

    ps. I'll be leaving for a 600 mile road trip to be in SF in the next 12 hours. Maybe I'll run into you. :biggrin: I have to be at a BBQ tomorrow, and a wedding on Saturday.
     
  6. Jun 24, 2016 #5
    http://www.jpl.nasa.gov/news/news.php?release=2016-154
    http://edition.cnn.com/2016/06/16/us/nasa-asteroid-circles-earth/
    50 years ago gives 1966 so maybe it's another Saturn V S-IVB third stage like J002E3 from Apollo 12? It would be easy to test.

    https://en.wikipedia.org/wiki/J002E3
    Maybe the modified stage 3 of AS-203, launched on July 5, 1966 wasn't inadvertently destroyed along with stage 2 after all. The modified stage 3 used would have to be very close to the weight of a normal stage 3 for the results to be useful.

    https://en.wikipedia.org/wiki/AS-203
    It could also be the third stage from Apollo 8, 9, 10 or 11 which are all recorded to have reached heliocentric orbit.

    https://en.wikipedia.org/wiki/S-IVB#Stages_built
     
  7. Jun 24, 2016 #6

    OmCheeto

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    Very interesting. If I weren't so busy, I'd figure out if this feasible. And I'm not sure if I'd be able to find all the data necessary to figure it out. Perhaps my pen-pal at JPL might know. :oldsmile:
     
  8. Jun 24, 2016 #7

    mfb

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    They certainly studied that. They wouldn't announce it that way if there was a chance to be a rocket stage.
     
  9. Jun 25, 2016 #8

    tony873004

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    Probably a mistake from the author of the CNN article. One sentence after saying scientists say its been out there for about 50 years, they quote a scientist saying it been out there for nearly a century.

    And by "a century" he means in a quasi-state for a century.
    They found a precovery image dating back to 2004, so they are very confident with this asteroid's orbit. Rocket stages are heavily perturbed by non-gravitational forces due to their low density. So its much more difficult to predict its trajectory.
    Also, its very unlikely that something would escape Earth and immediately enter a quasi state.
     
  10. Jun 26, 2016 #9
    J002E3 was also thought to have ended up in a semi stable orbit around Earth and left Earth orbit in June 2003.

    https://en.wikipedia.org/wiki/J002E3#Discovery
    The stage 3 from AS-203 would actually have a mass, and subsequent density, of around 10 times more than a normal Saturn V S-IVB third stage with an expended fuel payload so it would be expected to behave differently and have a different trajectory. I assume NASA would have simulated the payload mass so they could get accurate and useful results from their tests.

    http://history.nasa.gov/SP-4029/Apollo_18-19_Ground_Ignition_Weights.htm
     
  11. Jun 28, 2016 #10

    tony873004

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    Yes, but it didn't enter a quasi-orbit such as the one 2016 HO3 is in. It simply entered an Earth-crossing solar orbit. Quasi orbits prevent close approaches to Earth. Getting captured into and out of Earth orbit makes it more like asteroid 2006 RH120. http://orbitsimulator.com/gravitySimulatorCloud/simulations/1433806156068_2006 RH120.html
    This asteroid got captured into Earth orbit in 2006, made 3 orbits then escaped. But it was never in resonance with Earth.

    That's a good point. I thought we were talking about an empty tank. Thanks for the clarification.
     
  12. Jun 30, 2016 #11
    Hi Tony, the stage should be empty.

    I have just read the "RESULTS OF THE SECOND. SATURN IB LAUNCH VEHICLE TEST FLIGHT - AS-203 from NASA and must say I learnt alot and am very impressed with the massively great contribution the S-IVB guys made to the entire Apollo program, with the limited resources at their disposal.

    After reading the NASA report and comparing the figures with the other Apollo missions it is apparent that the S-IVB stage used live fuel loads that were expended successfully before telemetry was lost so the AS-203 S-IVB stage would be a similar weight and density to J002E3. Comparing the S-IVB stage weight total and Instrument Unit weights for AS-203, Apollo 7, 8, 9, etc shows that the S-IVB stage weight change is due to the amount of LOX being carried as everything else is within a couple of % when payloads are excluded.

    AS-203 was carrying 5/8 of the LOX of the typical Apollo mission so the Mass to LOX ratio would give a power to weight ratio equivalent to firing an Apollo program S-IVB stage with a small payload while leaving the stage in a heliocentric orbit like many of the others. Were the AS-203 S-IVB stage to have 100% of an Apollo missions LOX load it could effectively lift an Apollo equivalent moon bound payload.

    There was enough LOX on AS-203 to launch a small payload onto an Apollo mission trajectory, the main engine run was complete and well accounted for, there was no record that it came down and the same weight specs apart from LOX were used as an Apollo program benchmark thereafter so I cannot really exclude 2016 HO3 from being something like AS-203 S-IVB stage 3.

    Back in those cold war days it would probably be considered a good idea not to show all of your cards at once, just in case someone tried to peek. I can understand that. What I can't understand is why you wouldn't do a full restart and burn test if the opportunity came along and you were ready (command 'J2 Engine Start On').
     
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