Questions tagged [trajectory-design]
Trajectory design is the process of designing the trajectory of a space mission so as to fulfill the larger design objectives for that mission.
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Escaping Earth - how could one attempt to find the best solution to this trajectory optimization problem in practice?
If there is a satellite in low Earth orbit, with a limited delta-v budget (but high enough to escape Earth) and limited delta-v-rate (thrust), how could one find an acceleration schedule and ...
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Could Falcon 9 push the second stage a little longer after MECO and before separation?
When watching Starlink launches I noticed the MECO/stage separation usually occurs at about 2m30s with the speed of about 8000 km/h and altitude about 65 km. After the separation the first stage with ...
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Are there any studies about "ping pong" cyclers between gas giants?
Imagine arriving at Saturn, jettisoning your passenger cargo, and then utilizing the massive gravitational pull of the gas giant to slingshot back towards Jupiter.
Due to the immense mass of these ...
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How do spin-stabilized rockets conduct gravity turns?
I was reading this NTRS document about a spin-stabilized solids-only small launcher. The paper mentions that the proposed design (called 428A) will be spin-stabilized during launch and gravity turn. ...
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Powered Explicit Guidance - Why wouldn't it be used?
I keep reading that the Powered Explicit Guidance equations (PEG) (detailed in the Technical note linked below) is (an approximation of) the most efficient way to get to space. That being said, I know ...
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Guidance and control inputs in autonomous satellites
I would like to know which are the standard navigation data available on a small satellite (in LEO). In particular, I'm trying to understand which inputs I should consider for the Guidance&Control ...
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How does one design a trajectory involving a lunar and Earth flyby and Lagrange points? What tools are used to calculate the initial guesses?
I'm trying to design a trajectory that takes a spacecraft from Sun-Earth L2 to a lunar flyby, to an Earth flyby and then to Mars (two flybys might be too complex, I might just do one). I've optimized ...
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Manual techniques for trajectory design
I am trying to locate methods of trajectory design that can be performed by hand calculations, specifically for low thrust methods of propulsion like ion thrusters. Can anyone recommend me any ...
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Installation procedure for NASA's Evolutionary Mission Trajectory Generator (EMTG)?
I am doing trajectory optimization, and want to use NASA's Evolutionary Mission Trajectory Generator (EMTG) software to investigate dates for various trajectories. However, this software does not come ...
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More advanced alternatives to Trajectory Optimization Tool?
I've been using Arrowstar's Trajectory Optimization Tool to plan interplanetary transfers, and it works well. The next thing I want to do is plan gravity assists from the Sun-Earth L2 Lagrange point ...
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Porkchop plots/launch windows for Sun-Earth L2 to Mars transfers?
I've been using Earth-Mars launch windows, found with NASA's Trajectory Browser and EasyPorkchop, as launch windows from the Sun-Earth L2 Lagrange point to Mars, with the logic that since the L2 point ...
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Optimizing trajectories with GMAT: how to understand the "Vary" parameters, and how to know what values to use for them?
I've been using GMAT in my free time to optimize trajectories, and have varied burn component values and spacecraft states, usually with success. The vary command in GMAT, with the Yukon optimizer ...
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GMAT: How do I prevent infinite propagation into the future, which causes the "requested epoch 95008.513478505 is not on the DE file" error?
I have a spacecraft I am trying to get from Earth to Mars. I use an Earth propagator until the SC is out of the Earth's sphere of influence, then a deep space propagator until Mars' sphere of ...
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Is there any software or other resources that can find optimal launch windows and gravity assist trajectories involving Lagrange points?
I've been using GMAT to make various trajectories involving the Sun-Earth L2 point. Earth-L2-Mars, Earth-L2-Earth flyby-Mars, etc. However, the main source of optimal launch windows I've been using is ...
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How can Artemis 1 take so much longer for Earth-Lunar transit than the Apollo missions did?
The Artemis I mission will take 8-14 days to get from Earth to the Moon. Apollo 11 only took 3 days. Similarly the return will be 9-19 days for Artemis I and just over 2 days for Apollo 11.
Why is the ...
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How do I construct halo orbits around the Sun-Earth L2 point in GMAT? What should the state vector of the spacecraft be?
I am new to trajectory design, and have been using GMAT to learn it since it's free, unlike STK. I have been trying to design a script that takes a spacecraft from Earth orbit to a halo orbit around ...
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NASA GMAT: Any good tutorials or methods to learn how to use patch points and control points to come up with viable and optimal trajectories?
I'm a beginner to trajectory design, and have to use NASA's GMAT software. It's been a few weeks now, and I have done the first four tutorials and managed to create a (very unrealistic and sub-optimal)...
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Why does targeting in the VNB frame lead to a different maneuver magnitude than targeting in an inertial frame?
In GMAT, I set up a targeter (this script) to compute an impulsive maneuver in an inertial frame. The differential correcter finds a maneuver of 3.1161 km/s . If I change the impulsive maneuver to be ...
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Refueling a Mars mission on the way
Inspired by another question asking why we can't use faster rockets to Mars I came up with a naive question of my own ;-).
The answer to the first question is that the pesky rocket equation makes ...
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What is "mission design"? What do mission designers do (if such a designation exists)?
The question in meta Is the mission-design tag description wrong? Should the trajectory-design tag be somehow nixed? needs some attention, so I thought I'd turn to our "panel of experts" ...
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How many burns does New Shepard have during a descent?
The Falcon 9 first stage is making two or three burns for descending:
boostback burn (optional, depends on return to launch site vs ocean landing)
entry burn
landing burn
But how many burns is the ...
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How do you balance speed and exposure time when trying to reduce heating? [duplicate]
I'm trying to understand how you choose your acceleration/deceleration and trajectory during launch and reentry to minimize aerodynamic heating.*
Ignoring efficiency in terms of delta-v (best leave ...
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Why is the gas giant grand tour interval 175 years when the synodic period of Uranus and Neptune is 171 years?
The "Grand Tour" path Voyager 2 took, flying past Jupiter-Saturn-Uranus-Neptune, repeats every 175 years. As the original paper by Gary Flandro puts it:
Earth – Jupiter – Saturn – Uranus – ...
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How hard is it to fly through the tail of a comet? Has it been done?
The line between comets and asteroids is somewhat blurred (see below) but when we see a big bright tail we at least like to call it a comet. This question is about exploration of the tails of big-tail-...
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Which deorbit trajectory minimizes reentry heating?
Atmospheric reentry, as I understand it, is a balancing act between minimizing delta-v needed and not burning up or breaking up in the atmosphere. The higher the velocity on reentry, the greater the ...
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How to choose the best direction to leave Earth's sphere of influence?
What direction is optimal for spacecraft to leave Earth's sphere of influence (SOI) when it's going to an outer or inner planet?
Let's presume that we have a spacecraft in a circular LEO (ecc=0.0). ...
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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?
Time Magazine's UAE's Mission to Mars Launches Successfully—a First for the Arab World says that the Mars orbiter named Al-Amal (Hope) or Emirates Mars Mission:
...blasted off from the Tanegashima ...
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Why did Pioneer 11 use a gravitational assist to swing above the ecliptic plane... twice?
This answer to What do the shaded vertical lines in the animation of Gravity assists of space probes, mean? shows that the Pioneer 11 trajectory brought it close to both Jupiter and Saturn, and at ...
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How do the Dynetics-led team's ALPACA lander's "drop tanks" rendezvous and jettison work in terms of trajectories?
Ars Technica's NASA awards lunar lander contracts to Blue Origin, Dynetics—and Starship says:
NASA announced Thursday that it has awarded three contracts to begin initial development of lunar ...
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Outer planet trajectory design versus the asteroid belt
Several space probes have been launched to destinations beyond the asteroid belt: Pioneers 10 and 11, Voyagers 1 and 2, Ulysses, Galileo, Cassini, New Horizons, and Juno, at least.
While the odds of ...
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What ways can a University Student get involved in Trajectory Design?
As a physics student (not an engineer) in India, I can't seem to find a lot of opportunities to involve myself in what I find most appealing about what I'm studying in University i.e. astrodynamics. ...
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How do mission planners determine where to put trajectory control maneuvers (mid-course maneuvers)?
It seems to me that one could select a time for a TCM/MCM by finding the point in a reference trajectory where the velocity required to alter the position and velocity of the next trajectory point is ...
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Commercial 3DoF/6DoF trajectory simulation and optimization tool for launch vehicle
Is there any 3DoF/6DoF trajectory simulation and optimization tool for launch vehicles like POST available commercially? If there whether it's how reliable when it comes to using for real-time ...
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Launch vehicle trajectory tool for ascent phase to orbit using PYTHON
Currently, I am developing a trajectory optimization tool for launch vehicle from lift-off to orbit using python for my project. Since I'm new to optimization problem, I am finding it hard to ...
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Where did the Herschel Space Telescope go in 2013?
The Herschel space telescope wins as largest optical telescope mirror in space when "optical" includes far infrared (~55 µm). The Wikipedia article Herschel Space Observatory lists the orbit ...
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Mangalyaan + Trident; is it possible? escape the solar system using a low cost booster
5 years ago, India launched the Mangalyaan spacecraft to Mars, on a budget that raised eyebrows at the time. It was probably the Mars mission launched with the least powerful rocket; a feat only made ...
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Patched conic approximation targeting retrograde LLO yields prograde orbit
I'm playing around with optimization of a patched conic approximation for a transit from earth orbit to LLO, and when I take the resulting retrograde trajectory and plug it into an integrator, I get a ...
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What's the closest that an Apollo mission passed GEO on its way to the moon?
@Uwe's comment
No astronaut ever visited geostationary orbit at 22-23k miles to maintain or deploy satellites. The Apollo astronauts just rushed by on their way to the Moon and back.
below the ...
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Will the Parker probe use aerobraking at Venus? If not, why not?
The Parker probe needs to lose a great deal of orbital energy and angular momentum in order to approach the Sun so closely. It will be aided in doing that by multiple flybys of Venus. Are these purely ...
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What is the importance of thrust control history in low-thrust optimization?
As I have mentioned before, I am trying to optimize an Earth - Mars low-thrust transfer using a particular method. It has been mentioned to me, and I have seen it in many papers, that thrust history ...
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How accurate is the patched conic approximation when performing a Hohmann interplanetary transfer?
I've been making a Mathematica script whereby a spacecraft is transferred from Earth to Mars using a Hohmann interplanetary transfer by means of a patched conic approximation.
As far as I can tell ...
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