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A new update to the story of LMP-103s, the "greener" alternative to hydrazine links to Space.com's Orbital ATK's 'Frankenstein' Minotaur C Rocket Blasts Off on Halloween.

According to the article, Frankenstein's payload is six SkySats and four Doves.

Orbital ATK's Minotaur C lifted off from Space Launch Complex 576E at Vandenberg Air Force Base in California at 5:37 p.m. EDT (2:37 p.m. local time, 2137 GMT).

About 15 minutes later, the rocket deployed six SkySat Earth-imaging satellites and four Dove cubesats for the commercial imaging company Planet. "Liftoff of Minotaur C, carrying the SkySat and Dove satellites for Planet," Sean Wilson, director of corporate communications for Orbital ATK, said during a live webcast of the launch. [Gallery: Planet Labs Photos of Earth from Space]

The six SkySats appear to be SkySat-2 numbers 6 through 11 according to Gunter's Space Page. Most Dove's are deployed in larger groups, why only four on this launch? Just tests for comparison to SKySats? Perhaps this is an unusual orbit for them? Or perhaps they will be "watching" the SkySats deploy? (slightly related: Could a spy satellite image another satellite?).

below: A suite of SkySat and Dove satellites is encapsulated into the payload fairing of an Orbital ATK Minotaur-C rocket prior to launch. Credit: Orbital ATK, from Space.com.

payload

below: (Earlier launch, for scale) SkySats 4 through 7 take their places atop the Vega VV07 payload adapter – Photo: Arianespace/ESA/CNES/Optique Video du CSG, from Spaceflight101.

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    $\begingroup$ Just a guess, but there probably wasn't enough free volume or payload mass for more. The SkySats were the primary cargo; with the Doves shoehorned into the remaining space in the payload fairing. $\endgroup$ – Dan is Fiddling by Firelight Nov 1 '17 at 18:39
  • $\begingroup$ @DanNeely volumetrically,there seems to be room in the photo, but logistically it might require some custom deploy device that makes it unattractive, and ya weight can be a hard limit that one can't argue with. I'm still wondering if there is anything special about these four doves that made it worth the trouble to include them in the SkySat mission though. $\endgroup$ – uhoh Nov 2 '17 at 8:19
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    $\begingroup$ The timeline image OrbitalATK tweeted shows the separator between the two layers of satellites being ejected. That'd put a relatively larger threshold for carrying 5+ Doves vs slotting 4 into the existing empty space on the bottom tier. A 3rd tier would probably also have to go on the bottom since SkySat as primary would still want to be deployed 1st; with the top of the fairing narrowing that might've been a fit issue in addition to significantly increasing the cost to deploy each Dove. pbs.twimg.com/media/DNfx9EEVoAAt-29.jpg:large $\endgroup$ – Dan is Fiddling by Firelight Nov 2 '17 at 14:07
  • $\begingroup$ @DanNeely I see what you mean, thanks! It looks like Secondaries Sets A and B are the Doves, deployed hours after the final SkySat. Looks like you are getting close to an answer. i.stack.imgur.com/T1ozt.jpg $\endgroup$ – uhoh Nov 3 '17 at 1:17
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Rocket performance taking 6 SkySats to 500 km SSO limited the number of Doves that could be integrated. Also, they were not originally manifested on the mission, but were 'swapped in' after Planet's acquisition of Terra Bella from Google here.

So the number was the result of performance limits & logistics given the timeframe from acquisition to launch.

(by SkySat propulsion engineer)

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