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.

Filter by
Sorted by
Tagged with
4
votes
1answer
75 views

Question about orbital mechanics and trajectories for a space infrastructure project/climate adaption idea

I’m working on an alternate approach to the concept of using a solar shield to shade the earth from the Sun (to help with climate change adaptation). It would use streams of lunar soil from multiple ...
1
vote
0answers
42 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 ...
6
votes
1answer
129 views

What (the heck) are “space-fixed coordinates” as described in Apollo mission trajectory analyses?

@Ludo's answer to If I wanted to reconstruct an entire Apollo mission's crewed spacecraft trajectories, what are the key sources of historical data I'd look for? shows the table and its source shown ...
2
votes
1answer
123 views

What do these Apollo era terms mean?

@Ludo's answer to If I wanted to reconstruct an entire Apollo mission's crewed spacecraft trajectories, what are the key sources of historical data I'd look for? links to Apollo Mission 11, ...
22
votes
1answer
1k views

If I wanted to reconstruct an entire Apollo mission's crewed spacecraft trajectories, what are the key sources of historical data I'd look for?

The last few images in Robert A. Braeunig's Apollo 11's Translunar Trajectory; and how they avoided the heart of the radiation belts are fascinating and a bit perplexing as discussed in this answer ...
4
votes
1answer
87 views

Apollo lunar mission trajectory animation

Is there any animation of real trajectory (and real velocity profile) of any of the flown Apollo moon missions? Something similar to what is shown in the two following links, but using actual data ...
6
votes
2answers
587 views

What is the fate of SLA fairings jettisoned from lunar mission spacecrafts?

After TLI burn, just before Transposition, Docking and Extraction, the later design crafts jettisoned 4 pieces of the SLA fairing/shroud. These 4 pieces supposedly would follow similar path as the CSM/...
5
votes
3answers
1k views

Does trajectory of an object orbiting a planet depend on the object's mass? (With hypothetical Apollo example)

For example (hypothetically), if an Apollo crew of one of the lunar missions went on EVA just after Trans Earth Injection burn and carefully released a small bolt, or a plastic package from their food,...
1
vote
1answer
96 views

How to find the optimal launch trajectory for a rocket launched from a planet with an atmosphere?

I originally asked this question on maths stack exchange As the title states I am trying to find the optimal launch trajectory for a rocket launched from a planet with an atmosphere (Earth) in order ...
2
votes
1answer
87 views

STK Astrogator Earth Flyby

TLDR: How do you set up an EEV maneuver, specifically, how do you go from an earth orbit to a heliocentric orbit with a periapsis within Venus’s orbit in astrogator? I know the theory but astrogator ...
2
votes
0answers
28 views

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 ...
2
votes
0answers
69 views

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 ...
3
votes
1answer
446 views

What exactly is rhumb-line control in the context of a launch trajectory?

The conference paper SS-520 Nano satellite launcher and its flight result SSC18-IX-03 from the 32nd Annual AIAA/USU Conference on Small Satellites linked in this answer describes the use of rhumb-line ...
5
votes
1answer
88 views

How to choose between Hermite and Chebyshev interpolation for spacecraft trajectory?

There's a related question, but it doesn't seem to apply to spacecraft trajectories. Suppose you want to send a non-thrusting spacecraft far from earth, and you have ground tracking of the spacecraft,...
1
vote
0answers
55 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 ...
0
votes
0answers
26 views

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 ...
5
votes
1answer
90 views

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 ...
5
votes
1answer
201 views

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 ...
8
votes
2answers
2k views

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 ...
3
votes
0answers
37 views

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 ...
3
votes
1answer
58 views

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 ...
3
votes
1answer
215 views

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 ...
1
vote
1answer
55 views

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 ...
3
votes
2answers
259 views

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 ...
3
votes
0answers
67 views

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 ...
0
votes
0answers
118 views

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,...
2
votes
3answers
178 views

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 ...
3
votes
1answer
92 views

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 ...
16
votes
2answers
2k views

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 ...
2
votes
2answers
165 views

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 ...
3
votes
0answers
82 views

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. ...
2
votes
0answers
133 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 ...
3
votes
1answer
63 views

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 ...
6
votes
2answers
469 views

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 ...
1
vote
1answer
77 views

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 ...
5
votes
2answers
257 views

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 ...
11
votes
1answer
485 views

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 ...
2
votes
0answers
37 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 ...
4
votes
0answers
54 views

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). ...
11
votes
1answer
768 views

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?
6
votes
1answer
345 views

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 ...
8
votes
1answer
569 views

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 ...
3
votes
2answers
286 views

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 ??...
5
votes
1answer
231 views

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, ...
4
votes
0answers
70 views

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. ...
2
votes
0answers
61 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 ...
4
votes
0answers
39 views

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 ...
3
votes
0answers
58 views

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 ...
2
votes
1answer
74 views

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 ...
3
votes
0answers
54 views

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?