Questions tagged [trajectory]

Questions regarding the path that a spacecraft will take due to forces acting on the spacecraft, such as gravitational or radiation from the sun.

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Was there a close call for Voyager 2's extended mission due to lost uplink during the Jupiter encounter?

In Uplink-Downlink (2001), Douglas Mudgway says: "[The Jupiter radiation environment] . . . resulted in loss of the uplink connection with the [Voyager 2] spacecraft on the day after encounter. ...
Larry Gilman's user avatar
6 votes
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133 views

How do you minimise sum of atmosphere and gravity loss?

I am attempting to calculate the optimum trajectory of a space shuttle going into orbit, taking into account gravitational and atmospheric losses. How would it be possible to minimise the sum of these ...
piptheninjafrog's user avatar
5 votes
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Interstellar travel by lightsail – what are the main factors of the trajectory uncertainties?

Lightsail (solar sail or sail accelerated by lasers) is a theorized as realistic way for interstellar travel. Breakthrough Starshot is the most prominent example. Let’s assume we have a thin enough ...
Heopps's user avatar
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How large is the AoA during the ascent and descent of a Falcon 9?

If we divide the mission into ascent, descent before reentry burn, and descent after that, how large is the AoA (Angle of Attack) in each of these three phases? Is there any difference between the ...
جامکلو حسن's user avatar
5 votes
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When was Lucy's mission first scripted in Excel and why is that what Lockheed Martin chose to do it with?

CNBC's NASA spacecraft launches toward Jupiter asteroids on an intricate path charted by Excel Years before Lucy took off, Lockheed Martin mission architect Brian Sutter used Excel to chart the ...
uhoh's user avatar
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Falcon 9 plot of pitch angle vs time during launch?

I found this super helpful plot of the Saturn V pitch angle vs time during launch: Is there an equivalent plot for a typical (or atypical if must be) Falcon 9 launch?
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Where can I find data on satellite orbits?

I'm an enthusiast who'd like access to satellite orbital data to simulate / plot trajectories of manmade satellites (of any kind) on my home computer. Where's the best place for me to find this kind ...
Visipi's user avatar
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Economical Suborbital Trajectory Analysis Software

Got my two LR-101's, found some reasonably sized surplus LOX/RP-1 and pressurization tanks, found plans for fabricating valves, designed my vehicle, made an excel based back of the envelope sizing ...
user1559's user avatar
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What is the Delta V from the Moon to Earth Sun L1?

There are various proposals to build infrastructure at Earth/Sun L1 point, such as discussed in this question. From LEO the Delta V cost to L1 is about 3.5 kms or about kg of propellant in LEO for ...
GremlinWranger's user avatar
4 votes
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I'm trying to create a trajectory to Mars for a low thrust ion thruster engine using astrogator

I'm trying to create an optimize a trajectory to Mars for a number of low thrust high specific impulse engines. I am having trouble with the initial set up. I created a LEO exit spiral using a ...
Gwyn Davies's user avatar
4 votes
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How does the centre of mass of a spacecraft vary in a trajectory?

We all know that rockets have thrust along with a large mass flow, meaning that their mass is constantly depleted. For ground launcher rockets, the propellants form a large part of the mass and this ...
Rajath Pai's user avatar
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Proper handling of terminal guidance of finite burn closed-loop execution for rendezvous conditions?

I'm writing some software which uses Optimal Control Theory / Calculus of Variations / Pontrayagin's Minimum Principle / Primer Vector Theory to do closed-loop execution of finite burns (in KSP). ...
lamont's user avatar
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How much higher is the wave drag for a spaceplane compared to its induced drag

I'm working on the conceptual design of the path of a suborbital spaceplane and am trying to do basic calculations. I read that wave drag near the sonic barrier can be huge and can impede the flight. ...
Rajath Pai's user avatar
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How to specify constraints for launch windows

I'm trying to learn trajectory design and optimization, and I'm struggling to understand how one determines the launch window using trajectory design programs. I know that my satellite's initial ...
Translunar's user avatar
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Spacecraft Inertial Data

I am a developer of motion analytics algorithms. I have been using a 9 Dof strap-down IMU on human and land vehicles for these algorithms. I Would be interested to test my algorithms with IMU data ...
Bernard's user avatar
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Differential Equations for Rocket Launch in Polar Coordinates

I'm trying to understand the equations of motion for a rocket launched from earth, through the atmosphere, and into LEO. I found a set of ordinary differential equations which describe the motion of ...
Paul's user avatar
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Are there any free return trajectories for a manned Mars flyby mission between 2018 and 2024?

I am looking for a mission profile including the delta-v for burns for an interplanetary mission to Mars. I have been unable to find any free return trajectories between 2018 and 2024, are there any?
Galen's user avatar
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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 ...
kardalos's user avatar
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Why does the landing trajectory of a blunt body take an S shape in the lower atmosphere?

I coded some Matlab plots of altitude vs time for the re-entry of a point mass (so no aerothermo analysis included). In all the trajectories, there is an S shape closer to the ground. Why? Please ...
RNG's user avatar
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Tools for high-thrust trajectory optimization

I've tried using some of the freely available tools for making pork chop plots to explore the potential of transfers between planets. But as far as I can tell, these really are not designed for and do ...
ikrase's user avatar
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Where is this LightSail-2 trajectory data coming from? Is there more than TLEs available to the public?

This tweet shows high granularity data for LightSail-2's perigee and apogee, showing that while the apogee-raising strategy is working nicely, currently atmospheric drag is taking its toll and the ...
uhoh's user avatar
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3 votes
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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 ...
Translunar's user avatar
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Trajectory impact in case of STS hold down studs failure

The comment on this question made me think, suppose all holding studs mounted on SRBs do get failed, how much impact would it really result in trajectory, considering same fuel burn time of SRBs. ...
zephyr0110's user avatar
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variables affect the trajectory in a stochastic way

What are the different variables affecting the trajectory of a rocket in a stochastic way for getting potential three-sigma trajectory?
rocketengg's user avatar
3 votes
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149 views

Would you arrive sooner on Mars from Earth if you wait or if you leave immediately, when it's furthest from Earth?

Awkwardly phrased title aside, the question is as follows: If you wished to launch from Earth to head to Mars at the moment when the two planets are furthest apart, would you arrive sooner if you ...
temporary_user_name's user avatar
2 votes
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74 views

Calculating trajectory of Voyager 1 Python

I want to calculate the trajectory of the voyager 1 probe using python and Kepler equation. I know there are already various program to calculate it but I need to do it on my own via these ...
Gabriele's user avatar
2 votes
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181 views

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 ...
2080's user avatar
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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 ...
Gwyn Davies's user avatar
2 votes
0 answers
180 views

Earth to Mars Transfer using GMAT

I saw a couple of people mention here that in order to change the epoch date from the given Mars transfer example on GMAT I would need to change and re-optimize initial conditions. How would I do that?...
user47478's user avatar
2 votes
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Mission maneuver to Enceladus, I have some results from JPL trajectory browser, what comes next?

I am working on a project titled 'Astrodynamic mission maneuver to Enceladus'. I have found the launch date using NASA trajectory Browser. Can you let me know how to proceed further?
Smily's user avatar
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What is the preferred orbital trajectory for a rover/lander to land on a body?

With the new perseverance rover about to launch to mars, I have a question about landers and rover orbital trajectories. Do the landers/rovers circularize their orbit before landing on the body or do ...
Bruce Vici's user avatar
2 votes
0 answers
53 views

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. ...
Kartik Tiwari's user avatar
2 votes
0 answers
217 views

How should I fix this ill-conditioned trajectory optimization problem (launch vehicle ascent, direct pseudospectral transcription)?

I have a written some trajectory optimization code which can solve the "classic" Delta3 launch to GTO optimization problem in Betts, 2010. It uses direct pseudospectral transcription and so is ...
lamont's user avatar
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2 votes
0 answers
271 views

Payload fairing separation- Event based or time based?

Refer the answer for this question How strong and "hot" is the wind on the payload after the fairing is deployed at ~110km? It is clear that the fairings are separated when the free ...
Vasanth C's user avatar
  • 1,161
2 votes
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46 views

Trajectory information for Ranger, Luna, and other early Lunar explorers

Is there a location where I can get remotely reliable information on the trajectories for the old Ranger, Luna, and other lunar explorers? I'm especially interested in the ones that flew by the Moon ...
PearsonArtPhoto's user avatar
  • 121k
2 votes
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89 views

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 ...
Harvey Rael's user avatar
2 votes
0 answers
207 views

Given a constant thrust to weight ratio, how to calculate the quickest path between two points on earth?

I'm trying to understand what would shortest paths could looks like. Let's assume a few things We have a constant thrust to weight ratio We do not need to decelerate We need to take drag into ...
Antzi's user avatar
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2 votes
2 answers
230 views

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 ...
kardalos's user avatar
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How can I know which direction a launch will be?

I'm in SOUTH FLORIDA and try to watch all the launches from here. Sometimes, the rocket seems to head south and come right overhead. How can I tell what direction a launch will take? Thank you. M
user51798's user avatar
1 vote
0 answers
358 views

How to propagate the trajectory in GMAT with a custom thrust profile

So basically I was trying to design a low thrust maneuver to increase the apogee of the spacecraft. I solved it separately and got some thrust profile (thrust and it's direction as a function of time)....
Aryan's user avatar
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1 vote
0 answers
42 views

Apogee estimate starting from simplified one-dimensional numerical simulations

I asked a question on pen and paper apogee estimation and got an answer from @tom-spilker that called my attention: He said that he quickly estimated an inclined launch apogee from the results of a 1-...
curioso's user avatar
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1 vote
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Does the displacement angle change after burnout?

I came across the above image on Nakka's page about fins and what I understood is that rockets will turn into the wind during the thrust phase, and will drift slightly with the wind after burnout. But ...
curioso's user avatar
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1 vote
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98 views

How is it possible to connect trajectories at a Poincare section using the "bisection" method?

When constructing a heteroclinic connection (a connection between two different periodic orbits at two different libration points), the stable and unstable manifolds of two different libration points ...
John's user avatar
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1 vote
0 answers
214 views

Defining overshoot and undershoot boundary of entry corridor

I have been reading up on the mathematic of atmospheric entry. I have found different methods to theoretically calculate the corridor width but I don't understand how to define the overshoot and ...
Starck's user avatar
  • 11
1 vote
0 answers
201 views

How to plot conic from Lambert solver

I am trying to solve for an optimal multi-gravity assist trajectory from Earth to Saturn using Matlab. I have already solved for the departure and arrival velocities from and to each planet using a ...
Lisa's user avatar
  • 135
1 vote
0 answers
321 views

MATLAB optimization script for Low - Thrust trajectory

I'm trying to write a script for a 'shape based' trajectory, based on the exponential sinusoid shape, for an Earth - Mars transfer. Essentially, I know where I want to start, and I know where I want ...
Harvey Rael's user avatar
1 vote
0 answers
94 views

Are destination coordinates sufficient to travel to a far place?

Imagine we want to go to Alpha Centauri, Let's assume we are at position {100, 100, 100} and the star is at position ...
Eric Cartman's user avatar
0 votes
0 answers
64 views

How well can we predict asteroid impact location?

concern in December 2004 when initial observations indicated a probability up to 2.7% that it would hit Earth on April 13, 2029 - wikipedia on 99942 Apophis So we can predict that something might hit ...
Vorac's user avatar
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0 votes
0 answers
106 views

I want to write a program to calculate optimal trajectories, where can I find info on the maths

I want to write a program to calculate the optimal way for a spacecraft with a given engine to reach some body astronomical body with the minimum fuel burn (possibly adding in constraints on time, ...
Pioneer_11's user avatar
0 votes
0 answers
42 views

Hyperbolic manifolds in the spatial circular restricted three body problem and topology definition

I am approaching the study of hyperbolic manifolds originated from Lagrange point periodic orbits in the spatial Circular Restricted Three Body Problem. I can read in many papers that what we obtain ...
Daki's user avatar
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