Spirit photographs Phobos and Deimos
September 10, 2005 10:33 PM   Subscribe

Two Moons Passing in the Night. Mars rover Spirit took these sequential photos of Martian moons Phobos and Deimos passing overhead in the night sky. Those rovers are still going strong!
posted by brownpau (16 comments total)
I was hoping they'd look all cool & sci-fi filmesque. But then they ended up looking like two tiny white dots on an all black background, and I was sadly disappointed. I demand my money back from this post, brownpau. Less a 10% restocking fee, at the absolute most.
posted by jonson at 11:27 PM on September 10, 2005

It is remarkable that the rovers are still working.
They were built for a 2 month lifetime, or something?

Yeah, they are made of titanium, but props to whoever decided on the rechargable power system.

I've seen pictures of the sun from mars. It doesn't look bright enough to power a power hungry rover with small solar collectors.
posted by Balisong at 12:14 AM on September 11, 2005

I wonder about the life span prediction... Maybe 2 months was a political rather than an engineering requirement. I mean, you want the predicted life to be as short as possible, to help assure success, but long enough to justify the mission.

Regardless, an absolutely remarkable accomplishment!
posted by Chuckles at 1:25 AM on September 11, 2005

Way cool.
posted by Smedleyman at 2:02 AM on September 11, 2005

I heard that the NASA engineers pulled a "Scotty" and sorta-intentionally underestimated the lifespans of the rovers. If they lasted longer, they look like geniuses. If not, then they were 'right'. Everyone wins.
posted by NorthernSky at 2:14 AM on September 11, 2005

It is remarkable that the rovers are still working.

It mentioned that they had to charge the panels up all day to get this brief glimpse. The really cool part is that the scientists used the limited life left in the batteries to instruct it to recharge, then power up at a specific time and rotate the cameras to a specific position which they must have pre-calculated to capture this event.
posted by Civil_Disobedient at 4:04 AM on September 11, 2005

I wonder if martians have moon love songs

Varda La Luna
Com'e' che la camina

La passa i monti
il lago e la marina

Oi cara mamma
mi vago a prende acqua

la c'e' il mio amore
che a la fontana aspetta

ma se l'aspetta e anca se no aspetta

Varda la luna
com'e' che la camina

O giovinotto che tanto amor mi porta

Varda la luna
com'e' che la camina
posted by elpapacito at 5:37 AM on September 11, 2005

I'm so glad someone posted this. Thanks, brownpau! I think the Martian moon photos were taken on Sol 585, which was also the day Spirit took the pictures for the summit of Husband Hill mosaic and panorama. Oppurtunity's been the sexy rover for too long. It's nice to see Spirit back on top.
posted by steef at 5:52 AM on September 11, 2005

Husband Hill mosaic
posted by DrDoberman at 6:36 AM on September 11, 2005

The initial lifespan limit predictions were based on the assumption that dust would obscure the solar cells. Presumably the rate of dust accumulation could not be accurately gauged in advance and has been slower than expected. Apparently methods of clearing dust, like a window wiping brush, are not practical and would add deadweight the vehicles can not afford to carry. In March NASA said that Spirit had a new lease on life courtesy of a windstorm that blew dust off the solar panels.
posted by beagle at 6:52 AM on September 11, 2005

In the top left of the image, the star Kaus Australis seems to slowly appear. Any ideas on why this would be? I assume its some artifact of the imaging process (either collecting or post-processing), but it did seem a bit strange.
posted by forforf at 7:00 AM on September 11, 2005

The hurtling moons of Barsoom...
posted by Slithy_Tove at 7:43 AM on September 11, 2005

The orignal projected lifespan was 90 martian days (sols). This was simply the engineering goal Nasa had, meaning that they could guarantee (with reasonable caveats) the scientists that the rovers would not have any malfunctions before this periods end. The rovers are not built to break down after the 'expire end'; they are simply not built with the level of robustness and redundancy that would be needed for nasa to guarantee any longer period of functioning (and also what beagle said).
posted by Catfry at 8:14 AM on September 11, 2005

Phobos and Deimos Go To Mars from "Cords"- Synergy
posted by Jikido at 11:41 AM on September 11, 2005

Thank you, DrDoberman, for healing my busted link! MetaRule #3: no comments before coffee.

forforf: Many of the stars in that constellation image seem to brighten and darken. Simplest explanation: Martian cloudcover. Best guess: they picked images that best showed the moons, and/or altered them to best expose the moons for the time-lapse.
posted by steef at 2:56 PM on September 11, 2005

My girlfriend the astrophysicist also points out that this might be a Mars-rotation effect. As Spirit images Phobos and Deimos, Mars is rotating. So all of the stars and Phobos and Deimos appear to rotate around Mars' pole (north pole or south pole, which hemisphere is Spirit in again? And does Mars have a pole star? -- it wouldn't be Polaris necessarily, like here on Earth.) The field of view in one exposure appears rotated compared to the field of view in the next. During image processing, all of the fields would be lined up and rotated so north (or some other fixed direction) is up. So Kaus Australis may not originally have been in the field but then later rotated into the field.
posted by kyrademon at 4:04 PM on September 11, 2005

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