astronomy

Inclined orbit

Inclined orbit is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Inclined orbit rather than just read about it. In short: A satellite is said to occupy an inclined orbit around Earth if the orbit exhibits an angle other than 0° to the equatorial plane. This angle is called the orbit's inclination.

Key takeaways

Inclined orbit belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Inclined orbit to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Inclined orbit from memory before moving on to harder problems.

Reference excerpt

A satellite is said to occupy an inclined orbit around Earth if the orbit exhibits an angle other than 0° to the equatorial plane. This angle is called the orbit's inclination. A planet is said to have an inclined orbit around the Sun if it has an angle other than 0° to the ecliptic plane.

Types of inclined orbits

Geosynchronous orbits

A geosynchronous orbit is an orbit with an altitude of approximately 36,000 km (22,000 mi) that completes one revolution every sidereal day. If the orbit is perfectly circular and not inclined, the satellite will remain at a fixed point in the sky. If the orbit is inclined, it will the satellite will exhibit a diurnal motion up and down perpendicular to the equator. If the orbit is not perfectly circular, the satellite will exhibit a diurnal motion forwards and backwards along the equator. If the orbit is both inclined and elliptical, the satellite will trace out a small figure-eight shape in the sky. A geostationary orbit is a special case of geosynchronous orbit with no inclination and zero eccentricity, and therefore no apparent movement across the sky from a fixed observation point on the Earth's surface. Due to their inherent instability, geostationary orbits will eventually become inclined if they are not corrected using thrusters. At the end of the satellite's lifetime, when fuel approaches depletion, satellite operators may decide to omit these expensive manoeuvres to correct inclination and only control eccentricity. This prolongs the life-time of the satellite as it consumes less fuel over time, but the satellite can then only be used by ground antennas capable of following the north–south movement, satellite-tracking Earth stations.

Polar orbits

A polar orbit has an inclination of 90 degrees passing over the poles of the planet on each pass. These types of orbits are often used for earth observation and weather services.

Sun-synchronous orbits

This is a special type of orbit that precesses at the same rate that the sun moves along the ecliptic, causing the satellite to rise over a fixed location on the earth's surface at the same mean solar time every day. These orbits have an inclination governed by the equation:

cos ⁡ ( i ) ≈ − ( T 3.795 hr ) 7 3 {\displaystyle \cos(i)\approx -\left({\frac {T}{3.795{\text{ hr}}}}\right)^{\frac {7}{3}}}

where i {\displaystyle i} is the orbital inclination, and T {\displaystyle T} is the orbital period.

See also List of orbits Orbital inclination Non-inclined orbit

External links

References

Worked examples

Example 1 — a first encounter with Inclined orbit

Start with the simplest possible case. Write down what Inclined orbit claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Inclined orbit before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Inclined orbit ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Inclined orbit

In research: Inclined orbit appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Inclined orbit in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Inclined orbit is common in secondary-school and first-year university syllabi. It links to neighbouring topics Orbits, so understanding it makes those chapters shorter.
In everyday life: Look for Inclined orbit outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Inclined orbit in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Inclined orbit means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Inclined orbit out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Inclined orbit in simple terms?

A satellite is said to occupy an inclined orbit around Earth if the orbit exhibits an angle other than 0° to the equatorial plane. This angle is called the orbit's inclination.

Why does Inclined orbit matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Inclined orbit?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Inclined orbit.