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IMAGE Spacecraft found by Amateur and Radio Astronomer Scott Tilley (VE7TIL)

Discussion in 'Amateur Radio News' started by VE7DXW, Jan 30, 2018.

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  1. W0PV

    W0PV Ham Member QRZ Page

    OH! It's the article on the ARRL web site News that has the wrong call sign. That is where I picked it up. (So easy to blame the League for lots of stuff nowadays ;))
     
    VE7DXW likes this.
  2. VE7DXW

    VE7DXW Ham Member QRZ Page

    It was not the ARRL's fault. It was mine... my e-mail to the Rick contained VA7TIL - which is wrong Sorry for the confusion and thanks for pointing this out...
     
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  3. N6SPP

    N6SPP XML Subscriber QRZ Page

    hmmm... AO-7 Launched 1974, Dead 1981, Alive 2002 (to present.. mode A/B every 24hrs, sunlight only)
    Eric- n6spp
     
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  4. W1YW

    W1YW Ham Member QRZ Page

    It is important to understand that this --giant-- satellite was not 'lost'. It shows up prominently, presumably, on space radar, along with all the itsy bitsy junk out there.

    What NEW is that the satellite is now able to link and MAY be brought back up for its scientific mission continuation.

    It wasn't "lost". It had been "silent", and the mission was thus "lost".

    If you send a reasonably bright pea into orbit, Space Command knows about it.

    73
    Chip W1YW
     
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  5. W0PV

    W0PV Ham Member QRZ Page

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  6. W0PV

    W0PV Ham Member QRZ Page

    Then there was the amazing reception by AMSAT-DL of deep space probe ISEE-3 which spurred a ground-breaking crowdfunded private Reboot Project. They actually took over remote control of the spacecraft, attempted to fire thruster's to modify its heliocentric orbit.

    http://spacecollege.org/isee3/isee-3-reboot-project-status-and-schedule-for-first-contact.html

    Ex- KD4ETA set up an organization to do such "techno-archaeology" like recovering hi-res lunar images from NASA archives (and other stuff)

    http://www.skycorpinc.com/projects.html
     
    Last edited: Feb 1, 2018
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  7. K2WH

    K2WH Platinum Subscriber Platinum Subscriber Life Member QRZ Page

    Nice image of a rotating earth, but I have no idea what it signifies.
     
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  8. W0PV

    W0PV Ham Member QRZ Page

    In successive images, see the yellow-green blob form and move across the southern tip of the sideways outline of Africa west-to-east (toward Indian ocean). That's the effect of a solar eclipse, the shadow of the moon, on the upper atmosphere as seen in far ultra violet (FUV).
     
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  9. W1PJE

    W1PJE Ham Member QRZ Page

    Precisely. Molniya orbits, such as IMAGE is in, do not touch the neutral atmosphere much at all in the part dense enough to cause drag, and are accordingly quite stable. The resource limits are on the telemetry end - the Deep Space Network is quite overloaded - and also the expertise end to not accidentally command the satellite into permanent silence, or to cause a catastrophic instrument failure. Oh, and there's the engineering and control team to keep in place should the mission continue. (See the NY Times story about Voyager 1 and its remaining skeleton ops crew at JPL, including the PI Ed Stone.)
     
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  10. KW6JIM

    KW6JIM Ham Member QRZ Page

    What is IMAGES's transmit freq?

    73!
     
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  11. W0PV

    W0PV Ham Member QRZ Page

    2272.5 MHz carrier, +/- Doppler shift; sidebands +/- 1.7 MHz.

    See link in post #10 (tnx W6RZ)
     
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  12. W6RZ

    W6RZ Premium Subscriber QRZ Page

    A Molniya orbit has an inclination of 63.4 degrees. The inclination of the IMAGE spacecraft orbit is 90.01 degrees, so it's not in a Molniya orbit (but it is in an elliptical orbit). Also, not all elliptical orbits are stable. AMSAT-OSCAR 13 decayed due to perturbations from the Sun and Moon even though it's perigee was 2545 km.
     
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  13. VE7DXW

    VE7DXW Ham Member QRZ Page

    IMAGE is in a polar orbit because that lets you scan the whole planet in great detail, because earth rotates underneath it every 24h. As the space craft orbits it will above every part of the planet once. This is especially important if you want to measure ionized discharge in the polar region.
    ISS on the other hand does have a tilted orbit in relation to the equator and will never be able to see the polar caps without the optical distortion caused by a low viewing angle.
    Alex - VE7DX
     
  14. W1PJE

    W1PJE Ham Member QRZ Page

    Thanks for the correction - you're right (typing too fast). IMAGE is pretty stable, though, especially as this solar maximum was relatively wimpy and resulted in less global thermospheric drag.
     
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  15. W6RZ

    W6RZ Premium Subscriber QRZ Page

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