# Questions tagged [sun-synchronous]

Questions about orbits utilizing nodal precession so that spacecraft are able to maintain the same local mean solar time at any given point of an orbit. The effect is achieved through choosing inclination and altitudes of the apses.

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### Does the dawn-dusk orbit maintain the inclination with respect to the ecliptic plane?

I'm trying to understand the mechanics of sun-synchronous orbits, specifically the dawn-dusk orbit. If I understand correctly, the RAAN rotates around the plane of reference of the Earth, which is the ...
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### Time of satellite passing overhead

Curious lay person here... I download and analyze Sentinel-2 imagery for a variety of mapping tasks. According to the Sentinel mission description webpage: The Sentinel-2 mission orbit is sun-...
2k views

### how to better understand how dawn dusk orbits work?

I am starting to study orbital mechanics and I have some doubts about the sun-synchronous orbits and particularly about dawn-dusk orbits. I often read phrases like: Often, satellites in SSO are ...
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### Is a geosynchronous (SSO-like) polar orbit around the Moon possible? [duplicate]

Imagine the equivalent of a sun-synchronous Earth orbit, just substituting the Moon for Earth and Earth for Sun. Such an orbit would have to have the following properties: It would be a polar or near-...
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### Is it possible to determine the classical orbital elements for an Elliptic Repeating SSO?

As in the title, it is possible to have a repeatable Sun-synchronous orbit but with an elliptic eccentricity? If yes, which equations I have to consider to determine its classical orbital elements?
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### formula linking RAAN and LTAN

I just want to ask if someone does possess the formula linking the local hour to the right ascension of the ascending node (RAAN). I will try to explain myself: I know that I want my satellite to be ...
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### What maneuvers could be useful to move between two sun synchronous orbits with different times?

Consider two sun-synchronous orbits with similar orbital elements, except for their times. For example 8h and 9h orbits. Their semi-major axes (a), inclinations (i), and eccentricities (e) are the ...
839 views

### How risky is launching a rocket during a geomagnetic and solar radiation storm?

Today's launch of Arianespace Vega rocket deploying Sentinel 2A Earth observation satellite for ESA & European Commission went ahead as planned, lifting off on June 23, 2015 at exactly 01:51:58 ...
1 vote
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### Which Low-Earth Orbits Spend the Least Time With Access to Sunlight?

Regarding the (maybe completely absurd) possibility of powering a satellite via a ground-based laser, and perhaps (theoretically) also using that same laser to destroy any incoming projectiles or ...
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### Is there a low Earth orbit with a 24-hour day night cycle?

Are there any possible low-Earth orbits that use precession to match Earth's day/night cycle? So like SSO, but specifically aimed to achieve a 24hr day/night in LEO. If so, what would its parameters ...
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### Perturbation effects on sun-synchronous orbit

How do the following perturbation factors affect a sun-synchronous orbit? Atmospheric drag Solar gravity Lunar gravity Solar radiation pressure
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### Are sun-synchronous orbits possible around any body?

Sun-synchronous orbits are popular around Earth, and the Mars Reconnaisance Orbiter uses one as well (so I think Wikipedias definition as a geocentric orbit is wrong). Considering that probably any ...
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### Design and optimization of a Sun-synchronous repeating ground track orbit constellation

I am currently researching about this topic and am very new to this. Have no clue how to go about designing a group of imaging satellites (constellation) that are sun synchronous with repeating ground ...
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### How do orbits around Jacobi ellipsoids behave?

The Earth is a Maclaurin spheroid (aka. oblate). This affects orbits, most notably $J_2$ rotating the node line for inclined orbits, enabling thins like Sun-synchronous orbits. But the Maclourin ...
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### How does one dogleg from Florida to a sun-synchronous orbit?

From NASA Spaceflight's article SpaceX Falcon 9 launches first NRO mission with NROL-76: The NROL-76 launch was not to be targeting a sun-synchronous orbit, typically used by the NRO’s optical ...
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### MOM's NOT-so-sun-synchronous orbit about Mars - how large is it's J2?

edit: See my supplementary answer below for additional information. @@SE - stop firing the good guys nailed it. This question and answer started me wondering - how big is the J2 (oblateness) term of ...
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### Why can Amazônia-1 observe the Amazon "every day or two" while Landsat takes 16 days between observations? Is "orbital magic" at play here?

The news item in Science Brazil’s first homemade satellite will put an extra eye on dwindling Amazon forests says: Right now, Brazil’s Amazon monitoring program relies on flyovers from the U.S. ...
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### What are the most popular sun-synchronous orbits?

There are different kinds of sun-synchronous orbits (SSO) that differ in their right ascension of the ascending node and are usually named after the local solar time at the ascending node (LTAN), e.g. ...
178 views

### Who invented the sun-synchronous orbit?

I was explaining sun-synchronous orbits to a co-worker and he asked me who invented it and when. I could not find an answer on wikipedia or a quick google search, so I thought about asking here.
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### What would be different about satellite orbits if Earth were prolate? Would we have Sun-synchronous and Molniya orbits?

It's hard to imagine how it could happen naturally since on geological timescales the Earth would either be spherical if it didn't rotate, or oblate if it did, but from an orbital mechanical ...
1 vote
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### Length of time in a satellite spends in Earths shadow

I have come across a problem that has had me stumped for a while now. A spacecraft is in a Sun-synchronous Earth orbit with a =1.40 R⊕ and e = 0.2. The argument of periapsis is ω = 0◦ , and the ...
595 views

### How many flavors do dawn-dusk Sun-synchronous orbits come in?

In a series of comments below For a given 48 hour observing period, what fraction of the celestial sphere is available to CHEOPS? there's been a discussion of that spacecraft's dawn-dusk Sun-...
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### Maintenance manouvers for a Dawn-Dusk SSO?

I'm in charge of the ADCS for a class project, which consists on a 25U-cubesat, in a 650-km dawn-dusk Sun-synchronous orbit or SSO. What are the orbit correction/maintenance manouvers a spacecraft ...
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### Sun synchronous orbit and LTAN

I have to size the electric power system for a satellite on a circular, sun-synchronous orbit at 800 km altitude. In the problem I have been given the LTAN (Local Time of the Ascending Node) also, ...
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### Is it possible to have a "figure-8" orbit around the Moon and the Earth, and perhaps always face the sun?

Is it possible to have a 'figure 8' orbit around the Earth and the Moon? I'm looking for a non-decaying orbit that will not require significant rocket fuel to maintain, unlike the orbits used in the ...
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### How can I find orbital parameters for a sun-synchronous orbit?

I would like to compute ephemerides for a satellite on a sun-synchronous orbit, starting with only the following parameters1: altitude or inclination; local time of the ascending or descending node; ...
2k views

### Are sun-synchronous orbits always North to South?

So someone told me that weather satellites orbit from north to south generally because that helps them to obtain a sun-synchronous orbit (his explanation for why this was true was too complicated for ...
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### Mechanics of Sun-Synchronous Orbit & North Korea's KMS-4

QUICK QUESTION: Is North Korea's KMS-4 in a proper Sun-synchronous orbit? https://www.n2yo.com/?s=41332 2016-009A FOLLOW-UP QUESTION: How do I tell? I want to understand the mechanics. RESEARCH:...
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### Satellites that take advantage of, or require constant availability of sunlight on the spacecraft itself, available in Sun-synchronous orbits?

ditto: "Are there satellites that take advantage of, or require constant availability of sunlight on the spacecraft itself, available in Sun-synchronous orbits?" This question is an offshoot of this ...
1 vote
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### What is the darkest orbit around Earth?

What orbits around Earth has the least and most sun light exposure? I wondered: When taking pictures either of Earth or otherwise with various telescopes in orbit, does it help to be in Earth's ...
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### What is the official universal time system of Mars?

According to standing global treaty organizations specifications, 'What is the official universal time system of Mars?'
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### Are sun synchronous orbits possible for any place on Earth?

Do sun-synchronous orbit pass any spot around Earth at a specified local time? If yes or no, what is the reason? (I know that this type of orbit passes everywhere at the equator at the same local time....
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### Reason for satellite passes at the same local time each day?

Is there any specific reason especially for the remote sensing satellites passing at the same local time over a particular place each day? I have some experience measuring the radiance received by ...
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### How Local time of a sun synchronous orbit is related to Right ascension of ascending node?

My question may sound naive and hence would like to apologise if this question is already answered in same or other form in this forum. How does ...
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### Is there a significant difference between launching a polar orbit mission south from New Zealand versus launching it north?

The Channel News Asia article New Zealand launches into space race with 3D-printed rocket says: Ships and planes need re-routing every time a rocket is launched, which limits opportunities in ...
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### How are "terminator-riding" sun-synchronous satellites never passing over the pole?

The polar regions won't be missed as they will pass under the sun-synchronous orbit twice a year. – SF. Nov 19 '15 at 9:56 @SF. - Your comment is incorrect. Sun synchronous satellites never pass ...
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### If a sun-synchronous orbit passes over the poles twice a year, how can it have a constant (e.g. 98°) inclination?

I am sooooo confused. The answer to Are sun synchronous orbits possible for any place on Earth? ends with In short, yes, sun-synchronous orbits are possible for any location on Earth. and mentions ...
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### Could a cubesat in a 500km SSO orbit effectively monitor earth?

If you were looking for, say, a 1m per pixel quality, what focal length/sensor size would you need? Would there be any off the shelf/commercial solutions?
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### Rotation Of Line Of Apsides

Why does the line of apsides rotate in the plane of the orbit ? In case of a sun synchronous orbit does it have any effect on imaging accuracy or quality?
1 vote
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### Satellite Orbit-Sun Geometry of Sun synchronous Orbit

What is the difference in satellite orbit-sun geometry of Sun synchronous orbits of 6am local time , 9 am local time , 12 pm local time ?
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### Local Time Calculation

How To Calculate Local Time Of A Sun Synchronous Orbit With A Given Altitude ( Say 600 km ) , Inclination ( 98 degrees ) ?
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### Local Time drift of Sun synchronous orbit [closed]

How does inclination perturbation affect drift in local time of a sun synchronous orbit? e.g orbit with inclination of 98 degrees and height 600km with local time 10:30
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### Why does the Sun-synchronous orbital plane rotate?

I've seen this movie: It shows Sun-synchronized orbit of a satellite. What causes this orbit to be Sun-synchronized? I mean, from what I know, it shouldn't rotate as ...