# Tag Info

Accepted

### Venus-Mars-Venus cycler?

Is it possible to create a cycler that can travel from Venus to Mars, then back to Venus? Yes. When only two planets are involved, there are several infinite families of cycler orbits. Given the 434 ...
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### Is it possible to change to different orbit inclinations with a simple push?

No, a small push will not change a satellite's inclination by 90°. Remember that, when in low Earth orbit, a satellite is already travelling some 7-8km/s. A small push of only some m/s will leave the ...
• 9,854

### What is the least energetic trajectory design to send uncrewed supplies to Mars?

How do you minimize Δv to get to Mars? The answer is simple: Wait until 2018 or 2035. Those are the local minima in the Δv needed to get to Mars. The required minimum Δv varies by a large amount. ...
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### What is the least energetic trajectory design to send uncrewed supplies to Mars?

I don't think that's really the question you want to ask. The lowest energy trajectories are ones like you suggest, which achieve most of the energy to get to Mars with short impulsive burns very ...
• 57.9k

### Is it possible to "map" the Interplanetary Transport Network?

The Lagrange 1 and Lagrange 2 regions are the hubs of the trajectories that Ross, Lo, Martin, and Belbruno advocate. Szebehely developed equations to find the L1 and L2 regions. Using his equations I ...
• 15.2k

### Why does the Buzz Aldrin Mars Cycler not play a larger role in planning for Mars exploration?

A cycler makes sense where there is expected to be a small but steady shuffle of humans back and forth between Earth and Mars on a fixed timeline. Notably boarding and leaving a cycler involves more ...
• 17.8k

### Transfer between elliptical orbits

It is my belief that a bitangential transfer between two coplanar orbits is best. For such a transfer, no direction change is needed at departure or arrival since velocity vectors are parallel at ...
• 15.2k
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### Change of inclination using low thrust

I found this kind of counterintuitive as well at first. This is the way I rationalized it to myself: consider a high-thrust maneuver to change inclination. Obviously if it's impulsive, you perform it ...
• 633
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### What does the BackFlip lunar cycler do in its pass by Earth?

Page 10 of the article: "Earth-return trajectory that has a period of 1/2 month (or 1/3 month is some cases) in order to ensure return to the Moon after 2 (or 3) revolutions of the Cycler in its Earth-...
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### What uses would the Aldrin-Cycler have?

Well, you might get a huge amount of data back by putting a satellite with optical comms on a cycler orbit. A small(ish) satellite on a cycler orbit would pass by Mars and Earth with regular frequency,...
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### Are L1 to L2 and back "cheap" transfers/cyclers possible?

A connection between two different periodic orbits around Lagrange / libration points is often termed a heteroclinic connection. Although the L1 and L2 points in the Earth-Moon system are themselves ...
• 811
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### Would it be practical to fly a probe to Mars using gravitational assistance from Venus?

It is not practical to use Venus to get to Mars in all but one circumstance. I searched for Earth-Mars and Earth-Venus-Mars (EVM) trajectories in a 900 day launch period starting Jan. 1st 2024. The ...
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### What is the least energetic trajectory design to send uncrewed supplies to Mars?

According to this recent Scientific American article, there is a cheaper way to get to Mars than the traditional Hohmann transfer. The mission design relies on a ballistic capture to do away with the ...
• 7,411
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### How does bi-elliptic transfer compare to Low Energy transfers / Interplanetary Transfer Network?

To enjoy a bi-elliptic savings, destination needs to be greater than destination orbit by a factor of 11.94 or greater. Going from LEO to the moon certainly qualifies: 384,400/6678 = ~58. I'll pull ...
• 15.2k

### Transfer between elliptical orbits

I can give you an upper bound for the necessary $\Delta v$, between all elliptical orbits, regardless of inclination. You can always do a bi-elliptical transfer, performed by almost reaching escape ...

### Low Energy Transfer within Earth-Moon system

Wow, three years and still no answers!. I will give it a try. What I am going to answer applies just for transfers between periodic orbits at the Lagrangian points (the OP asked so many things but I ...
• 1,712

### Change of inclination using low thrust

I would like to share a GMAT example that demonstrates the thrust node changes for the low thrust satellites. In this case my example relays on electric thrust with low Isp and N. Finite burn at the ...

### What is the cheapest possible way to land a crew of 2 on the moon?

While the overall scope is too broad, let me address the "low energy transfer" part. Firstly, the idea of "gradually increasing apogee" doesn't save you any fuel. Chandrayaan-2 did ...

### What is the least energetic trajectory design to send uncrewed supplies to Mars?

In addition to possibilities outlined in your post, you can also take advantage of the fact that (gross simplification ahead) orbits around Lagrange points are possible, but very unstable, letting you ...

### Change of inclination using low thrust

This is a well-known phenomenon in helicopter dynamics and in control systems. In a second order control system (which roughly describes your low-thrust scheme), the phase angle change is 90° when the ...
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### Cyclers To Mercury?

Usable Mercury cyclers exist. Given the large inclination of Mercury, we want the encounter to happen along the line of apsides, thereby requiring a quasi-periodic stationary cycler. The simplest ...
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### Travel time from lunar orbit (EML2) to Jupiter using skyhook only?

Transfer Regardless of how escape from the Earth system is achieved, orbital mechanics pose some restrictions on travel time. The minimum velocity transfer possible is an elliptical transfer orbit ...

### Transfer between elliptical orbits

I don't know the answer for certain, but am willing to hazard a guess that the most efficient way of transferring between a circular orbit and an elliptical orbit, assuming for a moment that they are ...
• 7,212
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There's two ways to view your proposal; If you can do impulse burns but not constant acceleration burns, like your mention of multi-stage accelerations suggests, then what you describe is a series of ...
• 75.7k
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### Is the Jacobi constant stationary along a periodic orbit?

Yes it is constant along the trajectory as the Jacobi energy is computed using the initial state vector. From Wikipedia's Jacobi integral: In celestial mechanics, Jacobi's integral (also known as the ...
• 1,357
1 vote
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### Trajectory Optimization To The Moon (Case Study: Chandrayaan-2)

A study on such transfers requires the knowledge of : Optimal Control Theory and Optimal space trajectories https://www.elsevier.com/books/optimal-space-trajectories/marec/978-0-444-41812-8 This ...

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