Mars Sun-Synchronous Orbit

Does Mars offer the possibility of a sun-synchronous orbit? I'm
playing with an idea for orbiting reflectors to warm Mars and assist
in terraforming. It would increase efficiency if the reflectors were
never eclipsed.

Bill Bogen wrote:
Does Mars offer the possibility of a sun-synchronous orbit? I'm
playing with an idea for orbiting reflectors to warm Mars and assist
in terraforming. It would increase efficiency if the reflectors were
never eclipsed.

Yep:
http://mars3.jpl.nasa.gov/mgs/overvu...f/mapping.html

MGS has an afternoon orbit to give the sensors consistent lighting conditions.

Karl Gallagher
Northrop Grumman Space Technology

In article ,
Jorge R. Frank wrote:
I guess a more general question would be, is there a convenient reference
for the J2 constants for each planet? ...
I imagine J2 must be known at least fairly well for Venus, Mars, and
Jupiter since we've placed orbiters around all of them.

Appendix D of Vallado, "Fundamentals of Astrodynamics and Applications",
2nd ed, has them.

Another very useful reference, which has the J2s among much other useful
data, is Lodders & Fegley, eds, "The Planetary Scientist's Companion".
--
MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer
first ground-station pass 1651, all nominal! |

(Henry Spencer) wrote in message ...
In article ,
Bill Bogen wrote:
Does Mars offer the possibility of a sun-synchronous orbit? I'm
playing with an idea for orbiting reflectors to warm Mars and assist
in terraforming. It would increase efficiency if the reflectors were
never eclipsed.

Yes, Mars sun-synchronous orbits are much like Earth ones. MGS is in
a sun-synchronous orbit, and I think Odyssey is too.

You might want to read Colin McInnes's paper in the March/April 2002 JBIS
on where you can put solar reflectors in the vicinity of Mars. The
problem turns out to be more constrained than you might think -- remember
that any big lightweight reflector is also a solar sail! -- although there
are solutions.

I was envisioning a cloud or ring of tiny metallic particles; not as
efficient as giant panels but perhaps easier to manufacture. When I
play with a vector diagram for a given particle (Sun on the x-axis to
the left of the origin, Mars on the origin, particle at varying
distances up the y-axis, orbiting around the x-axis), it seems that
one might balance the light-pressure force pushing the particle to the
right by shifting the particle a bit to the right. Then the vector
from Mars' gravity points down and to the left, balancing both the
light pressure and the particles centripital force. Since Mars'
gravity varies inversely with the square of the distance to the
particle, I end up with a shallow-bowl-shaped ring of particles with
the opening of the bowl facing away from the Sun. But it seems like
it would be stable and might even reflect more light to the surface
than a flat ring since all the particles would not be perpendicular to
the Sun-Mars line and so would not block each others' light.

(Henry Spencer) wrote in message ...
In article ,
Bill Bogen wrote:
Does Mars offer the possibility of a sun-synchronous orbit? I'm
playing with an idea for orbiting reflectors to warm Mars and assist
in terraforming. It would increase efficiency if the reflectors were
never eclipsed.

Yes, Mars sun-synchronous orbits are much like Earth ones. MGS is in
a sun-synchronous orbit, and I think Odyssey is too.

You might want to read Colin McInnes's paper in the March/April 2002 JBIS
on where you can put solar reflectors in the vicinity of Mars. The
problem turns out to be more constrained than you might think -- remember
that any big lightweight reflector is also a solar sail! -- although there
are solutions.

Oops. I just realized that I was assuming the particles would 'start'
by orbiting perpendicular to the x-axis, the Sun-Mars line. My
mistake.

Henry Spencer wrote:
The problem turns out to be more constrained than you might think --
remember that any big lightweight reflector is also a solar sail! ...

Get Thomas Gold to design them.
--
Keith F. Lynch - - http://keithlynch.net/
I always welcome replies to my e-mail, postings, and web pages, but
unsolicited bulk e-mail (spam) is not acceptable. Please do not send me
HTML, "rich text," or attachments, as all such email is discarded unread.