Our own Ben Pearson's new article in Ars Technica Starman is out there, but we probably won’t see him again until 2047 points out:

A much closer pass will happen at Mars on April 22, 2035. The distance this time will only be about 1.4 million miles (2.3 million km), and has a small chance of being much closer. The predicted error is higher the further in time one goes, but at this point things are still accurate enough to be very confident it will be that close to Mars within three hours of the prediction.

It is theoretically possible that a telescope could be placed on Mars by 2035 that will be able to observe Starman. A one-meter telescope, such as the South African telescope that last observed Starman, could easily do it. With so many new super-heavy rockets being planned, one of them could possibly carry such a payload to Mars by then.

But what if Starman/Roadster had a modest camera, something like a wide field imager used on other deep space spacecraft that perform flybys of planets and moons, as well as some way to automate pointing, timing, shooting, and storing images using a small dedicated solar panel and battery?

Could a hypothetical "Starman Cam" see and image and resolve the disk of Mars in 2035? Or Earth in 2047? Then beam it back to Earth in 2047 or when it next passed through our neighborhood?

  • $\begingroup$ I'd call a Go-Pro, with the non-fisheye lens a modest camera. It's not a term I'd think to apply to a WFI... $\endgroup$ – JCRM Apr 11 at 14:10
  • $\begingroup$ @Antzi thanks!! $\endgroup$ – uhoh Apr 14 at 11:29

This is a cropped piece of a Starman Cam shot with the Moon, while it was near Earth, so about 380,000km. source.

enter image description here

Mars is about twice as big (diameter), but 2.3mln km is 6 times farther, so the result would be about 1/3 the size of the Moon in the photo, if taken with the cameras already installed on board. In my personal opinion - "a dot".

Of course these cameras have a pretty wide field of vision - even a modest zoom, or human eye would resolve the disc quite easily.

  • $\begingroup$ Holy granola, you've got real data! Nicely done. $\endgroup$ – uhoh Apr 11 at 12:07
  • $\begingroup$ It's also probable that "...something like a wide field imager used on other deep space spacecraft that perform flybys of planets and moons..." will have more pixels in a given FOV than this camera's live, public feed did. It may have had more pixels as well, but the live-feed might have been binned or compressed during its long journey from deep space to this YouTube post. $\endgroup$ – uhoh Apr 11 at 12:10
  • 2
    $\begingroup$ You know, I had never thought to try and find the Moon in the Starman video. Huh. Nice! $\endgroup$ – PearsonArtPhoto Apr 11 at 12:48

If the distance from the starman cam to Mars is 2.3 million km and the diameter of Mars is 6792 km, Mars is seen in an angle of 0.169 ° or 10 arcminutes.

If we assume a 45 ° lens and a sensor with 1024 pixels for the cam, the angular resolution is 0.044 ° or 2.6 arcminutes.

So Mars would be seen as more than a single pixel but not much more. Only a square of 4 by 4 pixels. Or 2 by 2 pixels for a 86 ° wide angle lens.

At the Earth flyby in 2047, distance to Earth will be 4.8 million km. Diameter of the Earth is 12,756 km and the view angle is 0.152 ° or 9.1 arcminutes. So Earth will be a very tiny dot just like Mars.

The wide angle camera of Voyager had a field of view of 3.169 ° and 800 pixels, so only about 43 pixels for the diameter of Mars.

The LORRI camera of New Horizons has a field of view of 0.29 ° and a resolution of 1024 pixels. It would resolve the diameter of Mars into 596 pixels at this distance. The effective focal length of the telescope of LORRI is 2630 mm.


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