zlacker

>>lawren+(OP)

  Data centers in space use 24/7 solar power

Maybe I’m just missing something obvious, but how exactly do you get 24/7 solar coverage in space? Surely they don’t propose launching all this stuff beyond LEO…?

EDIT: they cover it later on; if you think about it you can orbit on the exact line that is perpendicular to both the equator and the direction of the sun, and then have the orbit progress perfectly in sync with the earth’s orbit (`365.25/360`° of longitude drift per day) so that it’s always on this special orbit. So it’s like GEO but (presumably…?) way harder to maintain, and slightly more exclusive (how many could you safely pack in a constellation?). Not to mention the need to account for all the other LEO satellites to dodge this 4km wide square, and the much higher (presumably??) risk of debris/dust collisions.

This seems like a hat on top of a hat on top of a thousand hats, but Godspeed you mad geniuses. I would love to see this some day, perhaps if/when AGI trivializes some of the problems involved!

PS if my napkin math is right (`tan(4/800)*60` = 0.005 arc minutes) it wouldn’t be visible to the human eye at typical LEO altitudes, a threshold that Wikipedia puts around 0.5 arc minutes. We can pump those numbers up! As-is it would certainly be a sight to behold every day at dawn and dusk, that’s for sure…

>>bbor+p2
If you put it in a sun-synchronous orbit then it will always be in sunlight. Such an orbit would be in LEO.

>>Oliver+U2
Except when it's on the dark side of the earth - for half of every ~90 minute orbit.

A "sun-synchronous orbit" is typically a polar orbit that precesses so that it's sunside pass is always "over" the same local time (say, noon(ish)).

That puts it over the antipodean midnight time once it crosses the pole.

If you're thinking of a different orbit, how does that work?

>>defros+43
From the wikipedia article on SSO’s that I linked above:

> the dawn/dusk SSO orbit, where the local mean solar time of passage for equatorial latitudes is around sunrise or sunset, so that the satellite rides the terminator between day and night. Riding the terminator is useful for active radar satellites, as the satellites' solar panels can always see the Sun, without being shadowed by the Earth.

>>reaper+o3
That's a single SSO on the terminator.

There are many SSO's for all the times of the day, most SSO's are not permantly in sunlight.

The comment I replied to implied that any old SSO would have the property of being always in the sunlight, this isn't true.

The particular issue with a terminator SSO is that region will get crowded (sure, space is large) and one collision will seed debris to spoil it for everyone for some time.

> Riding the terminator is useful for active radar satellites ..

All sats need some level of power or another, not all want to ride the terminator, see (for one example)

https://modis.gsfc.nasa.gov/about/

in which different sats in the constellation travel at different times of day (why?).