Dictionary

• If you want to move this tab around, feel free to click and drag it around; place it wherever you like. If you press the downwards arrow along the top of the bar, you can change it from floating (it goes wherever you want), to docking (will snap along the screen), to integrated (will go wherever you want in your workspace).
• If you accidentally closed it, here's how you can find it! Along the very top toolbar, click "view". From there, find "5"; that will make your OB appear again.
• Double-click any item in this tree list to open its properties menu.

By default, you should have a 3D window where your central body is the Earth. 

If you want a new one, click "view" along the very top toolbar, then "New 3D Graphics Window". You can also duplicate an existing window via very similar means. 

By default, you should have this window open when you create a new scenario. 

If you want a new one, click "view" along the very top toolbar, then "New 2D Graphics Window". You can also duplicate an existing window via very similar means. 

• 9 times out of 10, an "odd" looking ground track pattern is just normal flat-map projection geometry. If you really want to know if it's normal, check the 3D window to see its true circular path. 

By default, it should be towards the bottom of your screen. However, the actual standard media controls (Play, Pause, Fast Forward, Reset) live in the 3D media toolbar just above your workspace with your graphics windows!

• If everything is frozen, that means you've probably hit the end of your global Scenario duration. Click that red reset button in the animation toolbar to rewind to the very beginning of your simulation period.

To get to it, click "Analysis" from the main toolbar along the top. Then, find "Analysis Workbench", and the first tab that you should be automatically on is the VGT tab. 

• If you need data that is NOT relative to the center of the Earth, use VGT and create a new coordinate system.

Do you remember what you named your scenario? That, in the OB, is what you'd double-click to get to its properties. It rests at the very top of the tree in the OB. 

• If you want to change the global mission timeline, you can open this object's properties and edit the analysis period's start and stop times.

From left to right, these are the buttons: reset (it's RED, jumps back to the beginning of the scenario period), step in reverse, reverse , pause, play, step forward, decrease time step, increase time step, "Normal" Animation Mode, Real Time Animation Mode, X Real Time Animation Mode. Let's go through some terminology:

• The timestep determines how much time is passing every time the animation updates. By default, this is 60 seconds, so the animation jumps ahead by 1 minute per frame. Thus, to step forward or backward is to jump back or ahead by your timestep.
• Normal Animation Mode runs as fast as your device can handle. Real Time Animation Mode locks itself onto your device's clock, only going as fast as "real-time". X Real Time Animation Mode is identical to the actual thing, except that you can multiply "real-time" by some constant to keep it moving smooth, just slightly faster or slower. 

It usually pops up in the bottom right corner of your screen. If something's gone wrong, it will tell you exactly what has gone wrong and where. 

• To clear the panel (if there's too many messages), right-click inside the panel and select "Clear All". 

To find it: Utilities (main toolbar, along the top of the screen) → Solar Panel Tool

You can input your panel surface area, efficiency percentages, and whether your solar wings are fixed or spinning.

• If you happen to have zero power generation, double check that you aren't paused in the middle of an eclipse in your timeline...

You can use this to toggle high-resolution satellite imagery, terrain elevation maps, cloud cover layers, and nighttime city light visualizations on and off. 

• If your 3D Earth looks ugly (pixelated, flat, etc.), consult the Globe Manager and make sure a) your terrain cache server is checked and active, and b) your local imagery files are checked and active. 

• If you're looking at the properties of an object with vision (e.g. a satellite), you can add lines of sight via the "Constraints" branch in the Object Properties tree. Specifically, you can add limits like minimum elevation angles. 

To get to it: Insert (main toolbar at the top) → New

• You have many ways to make a new object. Take a satellite for example. You could use the Orbit Wizard and define the orbit of the satellite using certain parameters, import the data of an active/retired real satellite, or load one from various file types.

To get to it: File (main toolbar at the top) → VDF Setup → Create VDF

The above is how you can make a standalone, shareable file. This is good if the person you're sending the file to is using the free viewer for STK. 

• If you're trying to share your scenario with your friend, and they can't see your data files, you've got two options. First, you use VDF setup to create a compressed .vdf file. Your other option is to convert the entire individual scenario folder that STK generated when you saved your scenario, into a zip file. 

To get to it: Insert → New → Facility.

Within the properties of the facility, you can input its exact latitude, longitude, and altitude coordinates.

• If your facility is floating in the air on the 3D globe, you probably accidentally wrote your altitude in kilometers instead of just straight meters. Otherwise, maybe your terrain data didn't load properly?

A simplified point on the map or in space that you want your satellite or ground station to track. 

NOTE: It does not have actual physical hardware like transmitters, like the ground station would. 

To get to it: Insert → New → Target.

You can drop this target onto a specific city or coordinate point. It acts like a benchmark placeholder to calculate line-of-sight tracking windows or imaging paths.

An object that defines the physical FOV (field-of-view) cone, camera footprint, or antenna beam width.

NOTE: It must be nested underneath a parent object, like a satellite or facility.

To get one: Insert → New → Sensor → (Parent Object)

• If you want your sensor to track the ground, you'll need to change its pointing properties. By default, satellite sensors in STK point straight down, meaning you'll need to change the pointing properties to "Target Tracking" to get the sensor to look at a specific ground station. 

A hardware component attached to an asset that generates and sends out radio signals at a specific frequency and power level.

NOTE: It must be nested underneath a parent object, like a satellite or facility.

To get one:  Insert → New → Transmitter → (Parent Object)

In the properties of the transmitter, you can define the exact carrier frequency and output power (in watts).

A hardware component that listens for and captures the radio signals sent by a Transmitter

NOTE: It must be nested underneath a parent object..

To get one: Insert → New → Receiver→ (Parent Object)

The parent object, in this case, is what ever is receiving the Transmitter's signals. Your frequency and bandwidth settings here must match your Transmitter EXACTLY, else it WILL NOT WORK. 

• If your link budget shows zero signal, even with clear line-of-sight, ensure that the receiver and transmitter frequencies match each other in numeric value and in units...

To find this: Right click your Transmitter/Receiver → Properties → Model

You can select standard analytical shapes, or upload custom .fna antenna map files.

To make one: Right-click the LOS access line between your Transmitter & Receiver → Report & Graph Manager → Link Budget

• Usually, the most important metrics to look at are E_b/N_0 and BER. If those fall below your hardware's minimum threshold, your satellite simply won't drop data. 

This value updates in real-time inside your link budget reports as your satellite orbits overhead and changes distance from the ground station.

This is used by the link budget to evaluate raw link performance before you lock in your final hardware data rate settings.

Unlike C/N, this value is completely independent of the receiver's actual bandwidth filters. 

THE "pass/fail" number for your link. 

• If you are below this value for your hardware requirements, your data packets will be completely corrupted. If you're above it, you have a link margin (essentially a safety buffer).

It is calculated in your link budget, and is based directly on your E_b/N_0 and modulation type.

Calculated automatically by STK based on pure distance and frequency. Typically the largest source of signal loss in your link budget.

Within the RF properties of your Scenario object, toggle atmospheric models (e.g. Crane, ITU-R rain).

• If your signal dropped without anything moving, this is what might've happened. STK will simulate statistical weather over your facility if you have a rain model enabled. High-frequency bands will take more of a hit than lower-frequency bands. 

Calculated automatically by STK when an atmospheric absorption model is checked in the Scenario properties. 

It becomes very punishing when a satellite is low on the horizon because the signal has to cut through way more air.

Causes your signal to fade erratically, or "twinkle".

"Enable it under the advanced environmental loss settings for fine-tuning high frequency ground-to-space links"

Tracked inside the link data reports. 

NOTE: Your receiver's tracking loop must be wide enough to accommodate this shifting frequency, or the signal will drift completely out of band during an overhead pass.

Within the properties of your Transmitter/Receiver antenna.

A higher gain value leads to a tighter, more powerful beam, but also requires more precise physical pointing. 

Used by STK as a baseline reference point to calculate the relative gain of all real antennas.

A definitive measure of "loudness" of your transmitter assembly found in your link budget reports.

A higher G/T value signifies that your ground station is incredibly sensitive and good at pulling weak, faint signals out of background space static. 

Within Receiver properties → Noise.

• Lower temperature is better because the colder the system noise temperature (in Kelvin), the less background static your hardware creates, making it much easier to hear your satellite.

Within BOTH Transmitter & Receiver Properties → Basic → Definition → Model Specs → Tick the checkbox "use" under Polarization 

• Typically, we use either RHCP or LHCP (Right/Left-Hand Circular Polarized) since circular signals don't care if the satellite is tumbling or spinning in place.

Computed automatically by STK based on the settings of the antenna. 

• If you mismatch completely (i.e. transmitter on RHCP, receiver on LHCP), you're going to drop a large amount of signal power that'll kill your download...don't do that!

Allocation Bandwidth: the physical width of the frequency spectrum channel your radio occupies

Data Bandwidth (aka Data Rate): the actual speed at which bits travel through that channel

Within Transmitter/Receiver properties (finish)

NOTE: Your receiver bandwidth must be wide enough to encompass your transmitter's signal plus any extra frequency room needed to account for Doppler shifts.

Within Receiver properties → Definition → Find the three dots next to the default receiver model, and switch it to the complex model

• Use this when you need to match your simulation to a real-world radio data sheet.

To get one: Insert → New → Radar

Radars can be attached to a ground facility to track incoming space debris, or dropped onto a spacecraft for Earth-imaging radar (SAR).

Right-click the access link → Properties → Attributes

You can make the link line turn one color when the link margin is healthy, and flash another color when the data corrupts.

To make one: Insert → New → Chain → Add your assets in order 

This allows you to test out long, multi-stop relay paths to see if data can successfully bounce from one asset to another to reach its final destination. STK will find the exact windows when data can hop through the entire network successfully.

To make one: Insert → New → Constellation → Put all of your identical objects inside of it.

It would be in your best interest to run a report against your target to check your overall global coverage. 

Configure by pointing a transmitter on Satellite A directly at a receiver on Satellite B. 

This is very important for tracking cross-country data relays in low-Earth orbit constellations.

Uplink: the command signal sent up from a ground facility to the satellite.

Downlink: the science data, pictures, or telemetry streamed down from the satellite to your ground tracking dish.

You need to make a pair consisting of a transmitter and a receiver for uplink, and another identical pair that'll just be for downlink. 

• Please use DIFFERENT frequencies across your pairs. If both pairs transmit and listen on the same frequency, your transmitters would effectively blind your receivers. Uplink needs its own frequency, and downlink needs its own, unique frequency.

If you're configuring multiple transmitters in a single scenario, ensure that their bandwidth allocations do not overlap with each other 

(You'd be accidentally simulating self-jamming!) 

The mathematical scheme used to mold digital 1s and 0s into a raw, analog radio wave.

(Standard styles include: BPSK, QPSK, high-density QAM)

Within your transmitter's properties

Which one should you pick? : 

• BPSK – slow but very rugged, perfect for critical emergency beacons
• QPSK and QAM pack more data into each second of download time, but require a precise, high power signal, else the bits will corrupt instantly

Configured in the advanced modulation tabs

Adding coding gain lowers the minimum E_b/N_0 your receiver needs to successfully reconstruct your data packets

To find it: Facility properties → Constraints tab → Elevation Angle

A good baseline is 5-10 degrees.

Why did my access times shorten? : Ground dishes can't talk through buildings, mountains, or thick smog. Forcing a minimum elevation angle will cut most of those things out.

To find it: Access tool →  Select your satellite, then your facility → Compute

This calculates your absolute maximum raw availability windows before any RF losses are even factored in

You could add a third-party transmitter to the scenario, label it as an "Interferer", and map it to bleed into your receiver's channel to analyze how bad your link margin degrades.

Under your antenna model properties, select "Phased array".

It's great from tracking multiple satellites simultaneously or rapidly shifting beams across a constellation

Used to simulate highly advanced communication payloads, like high-throughput satellites (HTS), that blanket entire continents in tiny, high-density cellular footprints

The absolute center vector axis of an antenna's directional beam shape. This is the vector path where the antenna achieves its maximum possible physical gain (0 degrees off-axis angle)

You can turn on the boresight vector line in your 3D Graphics properties to see exactly where your antenna is pointing relative to its target during an overflight

Under your satellite properties → Constraints tab → Body Masking

If you'd like, you can pick a 3D CAD model file so STK can use that in determining if your antenna is trying to send a signal through its satellite body

To enable it, load a Digital Elevation Model (DEM/DTED terrain file) into your Scenario properties → enable Azimuth-Elevation Constraint OR go to your facility object → check Use Terrain Data

It is generated in your Link Budget reports to determine if your satellite's signal beam complies with international space power radiation limits set by regulatory agencies

The Sun's massive natural RF radiation completely overwhelms a ground station's receiver.

To implement that, add a Sun constraint OR check Solar Outage in your link options

• You'll be able to predict exact seasonal dates when satellite downloads will temporarily drop due to solar alignments

Computed as part of your system noise temperature calculations when defining high-gain deep space or Earth-station dishes

Added as a fixed dB reduction field in advanced Link Budget templates to account for real-world circuit inefficiencies

To enable it: Right click your Transmitter → select Graphics → enable Contour Graphics

This will draw concentric geographic rings showing exactly where on Earth the link will be 100% operational versus where it fades out 

Selected via Satellite properties →  Propagator →  Orbit

Which propagator should you use?

Use Two-Body if you want basic physics, ignoring drag and other real-world imperfections. Use J2 if you want to account for the Earth's slightly squished shape. SGP4 is solely for loading NORAD TLE data. HPOP (High Precision Orbit Propagator) is best when simulating real missions because it accounts for drag, solar wind, and lunar gravity.

Found in the Satellite Orbit properties → Basic Type: Classical

The six values are: the semi-major axis, eccentricity, inclination, RAAN, argument of perigee, and true anomaly.

Found in the Satellite properties → set Propagator to SGP4 →  paste the 2 lines of text directly into the TLE field OR point it to a .tle text file.

STK will automatically match the orbit to real-world tracking data

You can view this in any standard geometry report.

How can you raise your apogee? → You can do this by firing your thrusters at perigee (the complete other side of the orbit). Burning in the direction of travel at perigee will push your apogee altitude higher.

Be sure to monitor your perigee altitude when designing LEOs. If your perigee drops below 150km, atmospheric drag will rapidly pull the satellite down to burn up in the atmosphere.

It is typed into the Classical Orbit configuration, as 1 of the 6 COEs.

Note that STK measures semi-major axis from the center of the Earth, not the surface. Always add in the radius of the Earth (6,371km) to your semi-major axis number, not just the altitude above the Earth's surface.

Set it inside the Orbit properties page. e = 0 is a perfect circle. 0 < e < 1 creates an ellipse. e = 1 gives you a parabolic trajectory, while e > 1 gives you a hyperbola.

Set in Orbit properties, and spans 180 degrees. 

An inclination of 0 degrees traces the equator, 90 degrees circles both the North and South poles, and anything greater than 90 degrees is a retrograde orbit (moving opposite the direction of the Earth's rotation)

It dictates where the satellite crosses the equator moving from the Southern to the Northern Hemisphere

Often used when spacing out satellites across a constellation. In giving 3 orbital planes RAAN values of 0, 120, and 240 degrees, you'd spread them evenly around the globe

For a perfectly circular (e = 0) orbit, this value has no meaning since there is no "low" point. When designing more eccentric orbits, it allows you to have apogee parked over a specific hemisphere.

True Anomaly is the actual geometric angle between perigee and the satellite's exact current position along its orbit.

Mean Anomaly is a theoretical angle that increases at a uniform mathematical rate over time.

Typed into the Orbit properties page under the location parameter. 

Use True Anomaly when you need to place a satellite at a precise physical point (e.g. exactly at perigee, v = 0)

Two competing coordinate systems for locating points on Earth.

Geocentric assumes the Earth is a perfect sphere.

Geodetic accounts for the Earth being an oblate spheroid, flattened at the poles.

You can set this inside Scenario/Object properties

Why is my target position off? → STK defaults to Geodetic because it matches GPS maps. If you or your script exports Geocentric coordinates without converting them, your ground targets will be off by several kilometers.

Displayed automatically in the 2D Graphics Window. Ground tracks shift westward on each consecutive orbit because the Earth rotates beneath the satellite's fixed orbital plane.

The shadow regions cast by planetary bodies. 

Umbra is the area of the total sunlight blockage (complete darkness).

Penumbra is the partial shadow boundary where the Sun is partially blocked.

To find this: Right-click Satellite → Report & Graph Manager → run an Eclipse Times report

This is critical for designing battery sizing and thermal control models.

Configured inside numerical propagators like HPOP. 

You must define the spacecraft's surface area, mass, and coefficient of reflectivity (C_r) for STK to calculate the pressure perturbation accurately

You can enable it under HPOP propagator settings.

Jacchia 1970 or NRLMSISE-00 calculate atmospheric density changes based on solar flux inputs to predict orbital decay rates.

Mathematical factors accounting for the Earth's non-spherical shape.

J2 causes the orbit's RAAN to drift horizontally and the argument of the perigee to rotate over time.

Handled automatically when using the J2 Perturbation, J4 Perturbation, or HPOP propagators.

Essential for designing orbits that rely on nodal precession.

Set your inclination to approximately 98 degrees (depending on altitude). This guarantees that the satellite will pass over any given spot on Earth at the exact same local solar time every day, keeping shadow angles consistent for imaging payloads.

How do I implement this? → Set a (semi-major axis) = 42,164 km, e = 0, and i = 0. From a ground station's perspective, a GEO satellite remains completely stationary in the sky.

LEO ranges from 160km to 2,000km in altitude, where fast orbital periods can be as low as 90 minutes.

MEO ranges from 2,000km to GEO altitude, so 35,786km. Commonly used for navigation constellations like GPS.

Defined by setting your semi-major axis / altitude parameters in the Orbit Wizard.

It is the default pointing vector for down-looking Earth-observation cameras and omnidirectional telemetry antennas.

You can toggle the sub-satellite point display on/off in the 2D Graphics properties. 

Determined entirely by your semi-major axis.

A typical LEO period (for 400-500km in altitude) is around 90 to 95 minutes.

Calculated when adding impulsive or finite maneuvers inside STK Astrogator. Your spacecraft's propulsion tank size dictates how much total Delta-V budget you have available before running out of fuel.

Set up inside Astrogator using 2 impulsive Delta-V burns: Burn 1 raises the apogee to the target altitude, and Burn 2 circularizes the orbit once you arrive at apogee.

Toggled inside advanced propagators like HPOP. 

While negligible for low LEO orbits, third-body gravity becomes a massive perturbing force for high MEO, GEO, and deep space missions.

Accessed inside the Targeter tool in STK Astrogator when setting up planetary encounter trajectory sequences.

Insert a Satellite → change Propagator dropdown to Astrogator.

Replaces basic Keplerian orbits with a sequence-based event stream (Launch → Coast → Burn → Target)

Essential for SSOs. For example, a 10:30 AM / 10:30 PM SSO satellite always crosses the equator when the local solar time blow is 10:30 AM, providing consistent lighting conditions for Earth imagery

Run a Beta Angle graph from the Report Manager. When beta = 0 degree, the satellite experiences maximum shadow time per orbit.

When beta is very high, the satellite stays in continuous 100% sunlight (full solar power, high thermal heating).

Use the Conjunction Analysis Tool (CAT) menu → load your satellite TLE and a secondary catalog TLE set → compute Time of Closest Approach (TCA) and minimum miss-distance spheres