37
votes
Do simulator games use a realistic trajectory to get into orbit?
I understand the reasons behind each of this manouveurs, however I'm wondering if this is how real rockets get into orbit.
Cutting off the engine and letting the rocket loose vertical speed looks ...
- 167k
35
votes
Accepted
Do simulator games use a realistic trajectory to get into orbit?
Physics
In regards to the physics, KSP is fairly realistic, other than it not modeling n-body physics (which isn't really relevant in scope of orbiting Earth/Kerbin).
In regards to the engineering, ...
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18
votes
Do simulator games use a realistic trajectory to get into orbit?
It's real, although many rockets heading to low orbit are engineered such that when the apoapsis reaches the desired altitude it's time to begin the final burn.
Remember that orbit is not truly zero ...
- 11.5k
17
votes
Accepted
What does a flight path angle of zero degrees mean at launch?
In this plot from Apollo Saturn V Postflight Trajectory AS 506
the confusion arises because this is the inertial flight path angle (in Apollo documents "space-fixed" == "inertial")...
- 178k
15
votes
Accepted
Could Falcon 9 push the second stage a little longer after MECO and before separation?
After the first stage engines are shut down, the only way for the second stage to extract energy from the first stage is to push away from it, which is how the separation already works. Attempting to ...
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13
votes
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Are there any dog-leg hot-spots? Where are dog-leg maneuvers used most frequently?
As ISRO launches from SHAR towards Bay of Bengal, they don't have much of launch azimuth, which is limited (can't recall the exact value). Whereas NASA and Rocketlab have pretty good launch azimuth ...
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12
votes
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Did UAE's Al-Amal (Hope) Emirates Mars Mission (EMM) launch directly into an interplanetary trajectory or did it spend some time in LEO?
What was the duration of the launch window this day?
According to Spacelaunchnow, the daily launch window was instantaneous, but there were daily opportunities from July 15 to August 12.
Did it ...
- 167k
12
votes
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Optimal speed per altitude for orbit launch
If the optimal speed is terminal velocity, this is the formula you need:
$V_t= \sqrt{\frac{2mg}{\rho A C_d }}$
where
- $V_t$ is terminal velocity,
- $m$ is the mass of the falling object,
- $g$ ...
- 126k
9
votes
Could Falcon 9 push the second stage a little longer after MECO and before separation?
Look at it a different way. If the two stages separated in a non-violent manner - i.e., one didn't "push" away from the other - then they would continue side by side (or end to end) as ...
8
votes
What is the highest inclination orbit ever attained from a Cape Canaveral launch?
To revisit this question, it does appear that the during the 1950s & 1960s, a number of extreme inclination and polar launches did indeed take place from Cape Canaveral in Florida.
The range ...
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7
votes
Accepted
For an Apollo Lunar Module Ascent Stage launch, what is the optimal profile of $\beta$ (or $\gamma$) vs time?
Given some simplifying assumptions (constant thrust, constant gravitational field, flying in vacuum, over flat horizontal surface), which aren't too badly undermined by the lunar ascent case, the ...
- 167k
7
votes
Do simulator games use a realistic trajectory to get into orbit?
Yes, in very broad terms this is how real spacecraft enter orbit. The maneouver is called a gravity turn, albeit KSP encourages (very) inefficient versions of it, just because it's faster (in terms of ...
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7
votes
How do control space launch vehicles ? Automotivelly (inbuilt commands) or from ground level?
The short answer to your question is GNC (Guidance, Navigation & Control). Mission planning is done based on nominal (normal) performance of all systems launched through a mean atmosphere for the ...
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7
votes
Powered Explicit Guidance: Should rocket be pitching down at orbital insertion?
This is a result of having low TWR on the orbital insertion stage, typically a characteristic of hydrolox. If you watch ULA streams, you'll see the DCSS & Centaur both do this as well. Basically, ...
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6
votes
What are the orbital-mechanical advantages of a long (100+ second) sub-orbital coast phase?
The Antares will have a long coast phase due to engineering related trade offs rather than orbital-mechanical advantages.
However from an an orbital-mechanical view alone, there would always be a ...
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6
votes
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What exactly is rhumb-line control in the context of a launch trajectory?
“Sailing a rhumb line” means holding a constant compass bearing. For short distances, this stays close to a great circle path.But at longer distances and/or higher inclinations, the rhumb-line path “...
- 12.6k
6
votes
What planning tools and techniques are used to avoid collisions in space during launches?
Currently, NORAD and others use large radar arrays to keep track of objects. Simplified trajectories are what appear in the common TLE databases.
Conjunction analysis is done by propagating the ...
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6
votes
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Was the gravity turn used in early spaceflight?
That section of the Wikipedia article is very poorly written, conflating interplanetary gravity assist in one case with gravity turns (prior to my ruthless edit), and should be in no way considered ...
- 167k
5
votes
Is there a pitch maneuver in launch vehicle trajectory to raise the perigee altitude in order to circularize?
You can think about it (approximately) by dividing the rocket trajectory into "up" and "downrange" parts. The "downrange" part is the largest one: To get to orbit, the rocket has to generate a lot of ...
- 12.6k
5
votes
Do simulator games use a realistic trajectory to get into orbit?
The 'coast' is a very natural part of getting to orbit. Burning close to the planet's surface saves the total amount you have to change your velocity by. The mechanics are a tad complex but the short ...
- 3,412
4
votes
Apollo 11 first stage separation
This plot shows the pitch profile for a Saturn V from launch to Earth Parking Orbit and it's described like this:
The vehicle rises nearly vertically from the pad, for approximately
450 feet, to ...
- 178k
4
votes
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Are 'classical' gravity turns still used and recognizable as such?
Ares I would have flown very close to an ideal gravity turn in the atmosphere. One paper that covers the simplest guidance of pitching it over on an initial azimuth and then flying it with basically ...
- 993
4
votes
What is the cause of the horizontal drift in the ascend path of the Starship and other rockets?
It's quite intentional. There's a significant risk that the vehicle will fail during ascent, and then there's the transition to the "skydiver" orientation and controlled descent using the ...
- 10.7k
3
votes
How and where can I determine the direction of a launch prior to liftoff?
welcome to Space Stack Exchange.
I'm going to take a guess that you mean "how can I determine the direction prior to the event?".
Go to the launch providers website and see what advance ...
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3
votes
What satellites were launched into a polar orbit from Cape Canaveral in the 1950s and 1960s?
Looking at Zarya, which lists all attempted launches and the orbits of all successful launches, there was never a successful launch from Canaveral to polar orbit. The highest inclination I saw was the ...
- 121k
3
votes
How to find the optimal launch trajectory for a rocket launched from a planet with an atmosphere?
Welcome to the site! I am afraid the answer you are looking for is not the one you want. Long story short, the optimal gravity turn must be calculated numerically, because the atmospheric density ...
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3
votes
Accepted
How do small, spin stabilized launchers follow a rhumb line?
In theory, a rocket could "follow a rhumb line" starting with any kind of directional information. But there seem to be two use cases:
The very-early Pegasus rockets used a directional gyro derived ...
- 12.6k
3
votes
Dynamics of a vertical launch vehicle trajectory
However, it is not so based on the above preliminaries, what might be the cause for this?
The linked paper does give a reason: "These specialized options are required to simulate certain ...
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3
votes
Is there a website with launch paths/visible regions?
FlightClub.io is very user friendly and its core (free) simulator tool is useful for seeing where the rocket is going. Professional launch photographers use Flight Club. The paid subscription to ...
- 9,685
2
votes
Looking for dataset of trajectory data consisting of latitude, longitude, altitude and time
Earth Satellites: get TLEs from Celestrak or Space-Track and propagate them with SGP4. One way to do that and to also calculate their ground tracks (latitude and longitude) is the Python package ...
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