Planet Labs earth imaging satellites

[Blackstar]

Do you know what is the constellation size they want to achieve?

[Blackstar]

Skybox Imaging, one of the three companies mentioned in the article, provides "sub-meter" resolution imagery.

Yeah, although I haven't found anything specific. Some articles say "about a meter or less," but that's still somewhat vague. I also cannot find any specifics on their satellites. What are the dimensions and what is the diameter of their imaging mirror? It looks like the satellite may be about 80 cm tall and 60 cm on a side, and I would guess that puts the mirror diameter at 40-50 cm. Somebody could then plug that into the satellite altitude and get a decent guess at the resolution.

http://www.wired.com/wiredscience/2013/06/startup-skybox/

[baldusi]

I understood they ha 50cm 2M satellites with 20 or so.

[Comga]

Just to note that 28 of these were carried into orbit today.

Ooh!  A Maksutov catadioptric imager.  Pretty!  Nice packaging, too.

Scaling the image yields an aperture of about 84 mm, based on the 100x100x300 mm standard size for 3U.

That says it can form a spot equivalent to ~2.5 meters full-width-half-max on the ground from 400 km altitude, with a "diffraction limit" of around 6 meters for half micron wavelength light.   

From Space.com "To best enable this mission, the company has selected a low orbit for its constellation and an optical resolution of three to five meters — a scale that allows measurement of a tree canopy, but does not compromise individual privacy," officials wrote in a June 26 statement announcing the Flock 1 project. "

Does anyone know of an estimate of the lifetime of these sattelites when launched from the ISS at around 410 km altitude?  It could be only a few months.

Once upon a time I suggested that a NASA team have the Japanese astronaut send something outside the ISS through the JEM airlock with the associated robotic arm.  They practically fainted and told me how ridiculous it was to ask them to participate.  How did PlanetLabs get them to agree to launch 28 3U nanosats, which I believe can only be launched two at at time?

edit: Images in this post show a dispenser that may be capable of launching 16 3U nanosats at once, not the two from the standard JEM launcher. That should reduce the amount of labor on the part of the astronauts, although it will still require some time for two cycles.

[jcm]

@PlanetLabs tweeted that the first pair of Flock-1 satellites are to be deployed at 0815 UTC  this morning, Feb 11.

[jcm]

And Will Marshall from PlanetLabs explained to me that the 16 3U sats are loaded onto the MPEP at once and taken
outside the airlock, but then are launched two at a time (with at least hours between launches). So that saves
time and resources on airlock cycles, but still seems like Wakata's got a full-time job there for a while.

[Comga]

And Will Marshall from PlanetLabs explained to me that the 16 3U sats are loaded onto the MPEP at once and taken
outside the airlock, but then are launched two at a time (with at least hours between launches). So that saves
time and resources on airlock cycles, but still seems like Wakata's got a full-time job there for a while.

The quantity of 16 was apparent in the photos.
Does Wakata need to be involved beyond positioning the RMS (arm)?
Can the delayed releases be triggered by timer or from the ground?
With such valuable time, the last thing an astronaut should be doing is sitting around watching the clock for fourteen hours.

[jcm]

Sounds like the releases are done from the ground, but Wakata will be doing photos of the first deploy.

First opp at 0815 UTC, second at 1240 UTC

NASA ustream now showing the deployer

[jcm]

New deploy time 0820 UTC

[jcm]

Deploy command sent, but no evidence of successful deploy on video..

[InfraNut2]

No joy at first try, but nice view...

JAXA still troubleshooting.

[jcm]

And the first two Flock-1 satellites deployed at around 0833 UTC

[InfraNut2]

Joy!

Two satellites riding off into the sunset, like in some high-tech western movie...

Hope someone captured video. Looked really good.  My screen capture did not do it justice.

[InfraNut2]

The satellites tumbled a little bit more than I expected, but it made for good visuals, as the setting sun highlighted different parts of them in sequence.

Subjectively, the deployment speed seemed rather fast, but it may not have been all that much faster than for J-SSOD. Hard to judge with different distances and angles of view.

edit: A pity Koichi missed getting close-in pictures of the deploy because Tsukuba did not give him a heads-up for the exact time of the re-send of the deploy command, but hopefully the further-out pictures he got will be OK. But they will get it right at the next deploy I expect.

[InfraNut2]

Koichi ready in the cupola to take pictures of the second deployment.

[jcm]

Two more satellites deployed at 1241 UTC!  Koichi reports photos taken, but I'm not seeing any relevant video on the iss stream...

[InfraNut2]

Third and fourth cubesats deployed 1241UTC. 

Koichi got good pictures. 

JAXA got good downlink video, but not me.    (The ISS feed showed an internal view of cygnus and the hatchway).

[InfraNut2]

@NanoRacks just confirmed (1353 UTC):

NanoRacks 2nd #Cubesat deployment from #ISS for @planetlabs went perfect...

[InfraNut2]

Koichi got good pictures. 

Confirmed    (This picture is from that second deployment).

@Astro_Wakata tweeted:

Congratulations on  the successful deploy of the satellites by the NanoRacks  CubeSat Deployer and Kibo robotics! pic.twitter.com/GsUzvC8NKO

[InfraNut2]

Another picture.

@NanoRacks:

This photo catches the cubesats just as they are leaving the deployer. #ISS #cubesat pic.twitter.com/QRybJb13pe