4
$\begingroup$

Where is the camera on the MarCo cubesat that took this "pale blue dot" type of photo of the Earth and the Moon?

Is there an official NASA web site for photos from the MarCo cube sats? This one is from Space.com's article Tiny, Mars-Bound Satellite Snaps Its First Image of Earth and the Moon.

More about MarCo spacecraft components (but not their cameras) in this answer.

enter image description here

enter image description here

$\endgroup$
4
$\begingroup$

MarCO features two cameras, both with 752 x 480 pixel resolution. They are located on opposite sides of the CubeSat.

One camera, a "color wide-field engineering camera" is mounted with the primary purpose of confirming deployment of the high-gain antenna. In order to do this it is mounted on the large side of the cube looking "up and out" at the antenna. It is identified on the left hand side of this CAD model from the NASA press kit for MarCO. It may be possible to see it in this image from an article by Emily Lakdawalla of the Planetary Society, but I cannot with certainty point it out.

However, as the high gain antenna appears in the image and this lines up with where the camera is supposed to be located, we can conclude with reasonable certainty that this is the camera that took the image in question.

For completeness, the second camera, the "color narrow-field camera" is located on the opposite face of the CubeSat, pointing in the direction of the UHF antenna.

$\endgroup$
  • $\begingroup$ Thanks for another great answer! It certainly does seem that this is it: i.stack.imgur.com/v0mB3.jpg If you think so, you could consider adding this or any helpful image directly to your post. At the top of the edit window there's an image importing tool. It's up to you though, it's not necessary. $\endgroup$ – uhoh May 17 '18 at 8:41
  • $\begingroup$ I don't want to do that as I'm not convinced beyond doubt that the camera is not the other item visible on the surface, to the left of the one your arrow points at. $\endgroup$ – Jack May 17 '18 at 10:54
  • $\begingroup$ I know what you mean, when you look at the 2nd image in my question, the microwave feed seen on the left edge of the image is below center, which is consistent with the position I've pointed at, and inconsistent with the other spot you've mentioned. Also, the thing I've pointed at is angled a bit so that it sees the microwave feed. If it were flush mounted, that would have to be a nearly 180 degree FOV fisheye, and then the reflectarray would dominate the right side as it is so much closer to the camera. $\endgroup$ – uhoh May 17 '18 at 11:09
  • $\begingroup$ That's just me thinking out loud. You are welcome to ignore it, I think your answer is great! $\endgroup$ – uhoh May 17 '18 at 11:16
  • $\begingroup$ I've added some diagrams with callouts pointing directly to the cameras at the bottom here. If you like you are welcome to add them to your answer and I can delete them from my supplemental answer. I'm really only interested in discussing the Mars photo in that answer, and since yours is the accepted answer it confirms what you've said, I think the diagrams will do the most good here rather than there. $\endgroup$ – uhoh Dec 28 '18 at 0:22
3
$\begingroup$

Each MarCO is equipped with two cameras. Both are 752x480 resolution, and connected to independent capture and processing computers.

The narrow field-of-view camera is aligned with the UHF antenna, so it will face Mars during EDL (Entry, Descent, Landing). The wide field-of-view camera is aligned with the high gain antenna, allowing it to verify deployment and image Earth.

Taken from Space Operations: Contributions from the Global Community, section entitled "MarCO: Interplanetary Mission Development on a CubeSat Scale."

$\endgroup$
  • 2
    $\begingroup$ The book implies (to me) that the WFOV camera would align with the HGA axis, allowing Earth imaging while the HGA talks to Earth. The image above seems to show the camera axis being 90* from the antenna axis, so presumably the WFOV camera is mounted between the HGA reflector and feed, and perpendicular so it can see both deployed. If I find more info on mounting locations, I'll edit it in. $\endgroup$ – Saiboogu May 16 '18 at 17:56
  • 3
    $\begingroup$ The wide-FoV camera is placed on the Cubesat body pointing out at the high-gain antenna. I'm other words, the direction the camera points is perpendicular to the direction the high-gain antenna points. Its primary purpose is to image the antenna to confirm deployment. Presumably then, the Earth pictures are just an added bonus, not for actual earth imaging. You can see more info and some CAD models on this planetary society post: planetary.org/blogs/emily-lakdawalla/2018/…. Hope this helps you clarify your answer. $\endgroup$ – Jack May 16 '18 at 22:33
2
$\begingroup$

One of the primary purposes of the camera is to confirm that the high gain antenna has been deployed properly. This requires that both the flat reflector (electrically "parabolic") and the antenna feed at the parabola's focus have both been deployed from the cubesat correctly.

The black item protruding is near the surface of the reflector and is tilted "forward" from the surface normal, allowing it a view of a large area of the patterned reflector as well as the tip of the High Gain Antenna Feed. The camera field would have been carefully calibrated and so the image of the reflector's pattern provides good data on any deviations in the reflector's deployed shape and angle.

The slightly offset location corresponds nicely with the offset of the antenna feed to the lower left in the image in the question, as well as the newer image of Mars shown below.

This has the right size, color, position, and orientation to be the camera, and nothing else fits those constraints.

below x2: Source: Planetary Society's Emily Emily Lakdawalla writes MarCO: CubeSats to Mars!

MarCo Cubesat Planetary Society

MarCo Cubesat Planetary Society

below: from Farewell to Mars found in this question

MarCo cubesat image of Mars


UPDATE! I just found these, which confirms it: https://www.jpl.nasa.gov/news/press_kits/insight/launch/appendix/mars-cube-one/

enter image description here

enter image description here

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.