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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Did Cassini's Titan flyby's have scheduled TCM's afterwards? If so, were they usually used?

In this answer I wrote: But while NEO's are fairly passive and only weakly propulsive (outgassing, photon pressure and thermal radiation effects) deep space spacecraft are active and substantially ...
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Explanation of single-burn trajectories from Lunar surface to Earth surface

I learned of the fine book Soviet Robots in the Solar System from this excellent answer. One chapter in it describes how the Soviets had extreme mass limitations on their lunar sample return vehicle ...
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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 as ...
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How does one “dump” or deplete propellant without changing spacecraft attitude or trajectory?

Occasionally one reads about a spacecraft "dumping fuel". It may mean expelling the propellant(s) as a liquid, or depleting them by burning them up. Although usually only fuel is mentioned, often ...
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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 ...
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Space trajectory Optimiztion

I understand that fuel mass is a major consideration of total vehicle mass and mission cost. Considering that earth passes Mars,I was wondering; If a trajectory optimization to Mars, similar to ...
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What would be the longest hypothetical emergency which would confine the Apollo astronauts to their suits?

This answer poses the possibility of an emergency that would require Apollo astronauts to spend the rest of the mission in their suits: A hole in the CSM might be more of an issue, since large ...
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what are various best practices/processes associated with orbit change manoeuvres of LEO / GEO satellites?

Suppose a satellite was supposed to burn X% fuel reduce Y% mass to gain delta V and change to different orbit in time t. But something is faulty with its propulsion system so it's burning more fuel to ...
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Most preferred coordinate system for Launch vehicle trajectory

To integrate the equations of motion for a launch vehicle trajectory to the orbit, which is the best coordinate system to consider of the following two: Rectangular with Earth-centered inertial frame ...
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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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Sharp nose or Blunt nose vehicle for higher rentry speeds?

Hypersonic Technology Vehicle 2 (HTV-2) is a crewless, experimental hypersonic glide vehicle rocket glider developed as part of the DARPA Falcon Project capable of flying at 13,000 mph (Mach 17.53, 21,...
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Instead of approaching Mars from behind can we approach Mars from the front of its orbital path? [closed]

Nine months is what google maps said to get to Mars. I would like to know if fuel was no expense how long could we get to Mars other than the method below? Is the 9 months and the method just what our ...
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How to calculate angle in elliptic orbit?

I would like calculate angle in elliptic orbit ZCP at any time, where: Z (position of periapsis), C (center of ellipse), P (current position of planet). I find topic, where is picture (in accepted ...
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Traveling through the asteriod belt?

The question What's the (particle) density of the asteroid belt? is about the density of objects in the asteroid belt. As a follow up related question and what I am interested in: When we send ...
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Terminology dispute: is an orbital flight still a ballistic flight?

We have a terminology dispute with a colleague: could a flight by elliptical orbit trajectory be called a ballistic flight as well or limits of the later is a parabolic trajectory of a suborbital ...
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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. ...
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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 ...
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How can I convert HGI coordinates to J2000 coordinates?

I am looking at old mission data such at this one from Vega 1. The coordinate system provided is HGI. Most of the data I have is in ICRF/J2000.0, as JPL Horizons provides. How can I convert between ...
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Did Apollo's velocity slow down after TLI due to Earth's gravity?

I assume Apollo's velocity slowed down after it left Earth orbit, for how long was it decelerating. Did it start accelerating as it approached the Moon. What was the rate of deceleration due to ...
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How low does OSIRIS REx's record-setting orbiting around Bennu go?

This OSIRISREx tweet says: It's official! I'm in orbit around #asteroid Bennu -- now the smallest body ever orbited by a spacecraft. My snug path around the asteroid also sets a new record for the ...
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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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Puzzler: Precisely what maximum distance from the Earth did the Apollo 13 astronauts achieve?

tl;dr: Both this answer and this answer quote Wikipedia to state that the Apollo 13 astronauts reached 404,171 km from Earth. I'm not able to reproduce that value. According to JPL's Horizons the ...
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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 ...
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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). ...
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What will happen to Parker Solar Probe in the long term?

Will the probe be intentionally crashed anywhere? Or is keeping space decontaminated not an issue here since temperature and radiation will sterilize anything in that kind of orbit?
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Is Hohmann transfer the most frequent transfer orbit?

I have to complete a project for a university exam. The task is to design an interplanetary trajectory from Earth to Saturn, and to compare it with a Hohmann transfer to the same planet. I also have ...
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How can I calculate the orbital elements from two position vectors and a time difference?

I have two position vectors for my satellite, and I know that the satellite reaches these two positions 15 minutes apart. I know I can find the inclination using linear algebra and my position ...
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What are the advantages of separating a stage few seconds after its burn out?

Will separating a stage(first) immediately after its burnout cause damage to the upcoming stage (2nd stage).? Also,do the first stage separation and second stage ignition happen at the same instant ??...
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How precise are spacecraft trajectory measurements?

Interplanetary mission trajectories are frequently likened in popular media to hitting a small target with a dart from vast distances, but in reality, spacecraft don't need absurdly high precision, ...
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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. ...
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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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What was Mariner 10's lowest perihelion radius?

I've been searching the web for documentation of Mariner 10's trajectory, notably the perihelion radii, but so far have turned up nothing quantitative, just some rough trajectory diagrams. I've looked ...
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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 ...
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The appropriate reference frame for the interplanetary missions

In the JPL Horizons there are Earth mean equator and ecliptic reference planes. The ecliptic is an apparent path of the Sun's ...
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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?
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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 ...
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Can someone give me a 'trajectory optimisation for dummies' answer?

So, I am currently doing a project on trajectory optimisation. I get the principle of it, minimise fuel cost for a journey, or try to maximise the spacecraft weight at target destination, and that ...
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Spacecraft Inertial Data

I am a developer of motion analytics algorithm. Having been using a 9 Dof IMU strap-down onto human and land vehicles for this algorithm. Would be interested to run my algorithm of a spacecraft IMU ...
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Mars transfer window frequency

According to this website I drew up a timeline of Mars transfer windows and the time you'd need to stay on Mars before the next return window: Blue to red arrows are Earth to mars transitions, red ...
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First interplanetary launch from California! How far from Earth will InSight be when it separates from the Centaur 2nd stage?

The Phys.org article Bound for Mars—countdown to first interplanetary launch from California says: In the early morning hours of May 5, millions of Californians will have an opportunity to witness ...
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Could an astronaut safely shoot the Sun with a gun?

I'm rather skeptical of this comic: I think a bullet's speed is insignificant to the orbital speed around the Sun, but is such possible without the astronaut falling into the Sun? Maybe with an ...
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Calculating spacecraft thrust manoeuvres with JPL data

I've recently programmed an animated simulation of the main elements (core planets and Sun) of our solar system: by using the initial coordinates from the JPL (Jet Propulsion Laboratory - NASA) ...
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How can I find sources for Launch Trajectories?

The trajectories of space launches and the deployment of their payload (both scientific and commercial) are certainly carefully monitored by the space agency or company providing the launch capability,...
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Earth polar orbit to Lunar polar orbit

Suppose you wanted to achieve a polar orbit around the Moon, starting from LEO. Would it be better to start from a polar orbit around the Earth? "Better" meaning using less fuel, having more frequent ...
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Can the Falcon Heavy handle deep space missions?

Can the Falcon Heavy rocket handle sending payloads past Jupiter like the Atlas V?
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Did SpaceX intend to overshoot Mars?

There seems to be a lot of buzz around the Internet that the now famous Roadster is going to overshoot mars. Was this intentional, just to show the kind of capacity it is capable of? Or was there some ...
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How long will it take for Starman to complete one orbit of the sun?

I have seen that the original estimate to pass by Mars was about 6 months, but the current trajectory overshot Mars by quite a bit. How long until Starman and the Roadster return to complete their ...
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Current position of Starman

Have looked at current videos of Starman and not found data as to it's current position. Is there a site plotting the current position of Starman?
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Starman trajectory in future

How will the Starman move in the future? So far I have seen it goes quite beyond Mars, but what happens after that, will it orbit sun in some peculiar orbit? Isn't it risk for future flights? I ...
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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 ...