# Questions tagged [delta-v]

Literal meaning is "change in velocity". The quantity has utility in rocketry as measure of the change in velocity that a reaction engine must produce to move into a given trajectory. The rocket equation establishes that the mass ratio of payload to initial mass is an exponential function of delta-v divided by the propellant velocity.

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### How do you calculate the percentage of light-speed a ship with a certain delta-v can achieve, accounting for relativistic effects?

I was doing some back-of-a-postage-stamp calculations on high-isp interstellar spacecraft earlier and realised something. If I design a spaceship which according to the rocket equation has a very high ...
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### Delta-v for landing on the moon

I'm doing a few calculations to understand how to go from the Earth to the Moon. I used an elliptical (Hohmann Transfer) orbit to go from LEO to a circular Moon's orbit performing two $\Delta v$ (...
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### What is the delta-v required to reach Titan (Saturn's moon)

How much speed do I need to put something to orbit on Titan? I know it is a simple question but look among those maps that are there but they are not clear to me.
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### Launch to orbit delta-v penalty from Venus compared to Earth?

Thinking about the no atmosphere caveat here made me think of Venus, which is the opposite of no atmosphere for solid/rocky bodies in our solar system. Earth's low orbital velocity is about 7.8 km/s. ...
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### How much Delta-V is needed for Orbital Maintenance?

My question is aimed at understanding the how much Delta-V is needed for orbital maintenance in different orbits. Obviously, there still is some residual air resistance that decreases as the orbital ...
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### What would the rocket equation look like for 4 ion thrusters?

If i have 4 ion thrusters(IFM Nano Thrusters), how would the rocket equation have to be done to calculate the total delta-v?
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### How to calculate delta v for orbit change around body; not necessarily Earth?

Let me express my joy at having found this great place of Stack Exchange. My question concerns the calculation of delta v requirements when already in orbit around a body and lowering or raising ...
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### What would be the best course of orbital maneuvers for soft landing an asteroid near the lunar south pole? [duplicate]

Wouldn't it be nice for a colony near the south pole of our Moon to have a nickel-iron asteroid on the surface nearby ! Thousands near-Earth asteroids (NEAs) have been discovered with a diameter up to ...
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### When is it okay or at least helpful to use energy arguments in orbital mechanics?

When faced with energy-based questions about spaceflight we often comment something like orbits are about momentum, not energy and use delta-v math in answers. But in this answer to How big a nuke ...
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### How to use specific impulse for multiple stages

I am given a scenario where I need to create a program to give the initial launch mass of a spacecraft that can vary between 4 and 20 stages. I am given that the "specific impulse for all stages is ...
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### What is delta-v calculated in reference to?

I understand delta-v is literally just the potential change in velocity, but this would obviously differ between air resistance, gravity and many other factors, so what is delta-v calculated in ...
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### Why did Voyager 2's velocity drop far below escape velocity before the first gravity assist?

As per @kasperd's comment on another question. Looking at the graph below, it appears that Voyager 2 started at just over escape velocity of the solar system. Just before the Jupiter flyby, it was ...
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### Can a Mars orbiter mass only 50 kg?

A press release by the SatRevolution consortium says that it plans to send cubesats "as small as 50 kg" to Mars to "conduct a variety of valuable science." So that means orbiting, not just a flyby ...
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### What is the optimal inclination change strategy?

Consider a transfer between two circular orbits of similar radius, the only difference being the inclination difference, $\alpha$. What's the minimal $\Delta v$ required to perform this transfer? ...
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### Delta-V required for lift-off from a planet/ asteroid

How can I find a estimation of the delta-V needed to lift-off from a planet and go into a low orbit around it?
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### Trivial lower bounds for single point mass delta-v problems?

Given two arbitrary elliptic orbits around an ideal single point mass, there will always exist a transfer with the minimal $\Delta v$ required. It's easy to find an upper bound for this ideal ...
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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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### Delta-v cost of longitudinal plane change correction?

In a recent question, the slow drift of a landing site on a rotating body relative to an orbiter came up. This would sometimes require a plane change correction when one desires to recover the ...
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### Is it really ~648.69 km/s delta-v to “land” on the surface of the Sun?

According to the following diagram it would require ~648.69 km/s to do all of the intermediate transfers that would land you at or around the sun's surface at perigee. Is this a real number? How would ...
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### How can I calculate the delta-v correctly, this way does not seem to be correct?

I'm learning about Astrodynamics, and I would like to ask how can I calculate the $\Delta V$ for an interplanetary mission. I used a website for the porkchop plots (http://sdg.aero.upm.es/index.php/...
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### Can someone help Scott Manley explain this Snoopy-capturing maneuver?

In his recent video Apollo 10's Lunar Module Snoopy Is Lost In Space - Could We Bring it Home? Scott Manley uses some fancy supplemental techniques in KSP to simulate and explain a possible mission to ...
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### Does the Delta v to leave the entire solar system depend on its angle to the ecliptic?

Does the delta-v requirement change depending on the angle a craft is leaving the ecliptic? If a craft were to be leaving only a few degrees above the ecliptic, would it take less delta-v than if a ...
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### How do you plot a porkchop plot like this one?

I was looking around for gravity gradients then got sidetracked by looking at pork-chop plots because they're extremely cool. I'm still struggling to fully understand them, but I did find an ...
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The recently launched Starlink satellites are designed to use their HAL Ion thrusters to seek their own independent orbits, evade collisions, and de-orbit at the end of their lives. That's a lot of ...
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### Delta V to get to the Sun-Earth Lagrange Point 1?

For any of these starting positions, GEO, GTO, EM-L2 or EM-L4/5, which would require the least delta-V to get to Sun-Earth L1? How much delta-V would it require? Would this chart help in identifying ...
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### Is there a general relativistic relativistic rocket equation?

I am not to familiar with rocket equations but I know that if you combine special relativity with classical mechanics you get "c" as a speed limit. Basically the closer you get to "c" the more you ...
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### What are Mass Rate(āv)/āv, Mass Rate(Isp)/Isp and time of burn(MR)/MR graphs?

I have some problems about Tsiolkovsky's Rocket Equation and some graphs. Firstly, I didn't get what I can do with Rocket Equation formulas as seen below, Also, what these three graphs try to mean? ...
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### Details about traveling from EM-L2 to SE-L1

Would the optimal time to launch be when the Moon was on the opposite side of the Earth from the Sun? What direction would be optimal leaving EM-L2, radially away from the moon? Is the last line of ...
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### Does it take more energy to get to Venus or to Mars?

Let's assume we use the ideal positions of those planets relative to Earth for launch. And let's assume the spacecraft is launched from the same place on Earth. Also let's assume the goal is to get ...
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### How much Delta-V would be required to escape the Gravitational Influence of the Earth without entering orbit?

As impractical as it sounds (and it's definitely impractical) I was wondering what the Delta-V required to leave Earth's influence would look like if we launched "just straight up" into the Earths ...
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### Delta-V to accelerate to/decelerate from .5c

I have a reasonably good understanding of delta-V (from playing KSP). However, I don't have a great understanding of how it works once you start running into the limitations of physics. I know that ...
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### Delta-V chart mathematics

Could someone explain me the mathematics behind the Delta-V charts one can find on internet such as:                 &...
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### Is there a list of space exploration mission ordered by “size”?

While playing KSP I came to realize how how counter-intuitive distances in space exploration are. Just because a planet is closer doesn't mean it's easier to get to. For example, I used to think ...
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### What would your altitude be after you had achieved escape velocity from the moon?

I have been trying to work out how much ĪV would be required to deorbit a spacecraft after it had achieved escape velocity from the moon but I don't know how to work out what the radius of the orbit ...
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### Does launching to interplanetary space from LEO require the least delta-v?

Based on this chart from wikipedia, (I do not know if I am reading it correctly) This all assumes LEO-Eq LEO to C3/0=3.22 LEO to GEO to C3/0=3.9+1.3=5.2 LEO to EML-1 to C3/0=3.77+0.14=3.91 LEO to ...
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### Delta-v to move from GEO to GEO

To move a satellite in geostationary orbit, 166Ā°55ā²E, to the antipode, 13Ā° 4' 3.2" W, what delta-V would be needed for this to be accomplished? As for time constraints, I do not know what are the ...
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### Have there been any correlations between rocket size and the delta V it achieves

Have there been any studies that discuss the delta V of the vehicle and compare it to the altitude of operation, or compare it across launchers. If not, what kind of criteria, would one look for ...
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### Is there an absolute limit to single stage āV when tank mass is a fixed faction of propellant mass?

Many space exploration fans are familiar with the rocket equation [https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation] $$\Delta V = V_{e} \times ln\frac{M_0}{M_F}$$ where $V_e$ is the exhaust ...
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### What would it cost to bring a 1 gram payload to the CMBR rest frame (i.e. Īv 368 km/s ?)

Suppose we wanted to do a very small experiment in (or very close to) the Cosmic Microwave Background Radiation rest frame, which we are travelling at 368Ā Ā±Ā 2Ā km/s relative to. Without considering the ...
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### Online Porkchop Plotter

Is there an online tool available to calculate porkchop plots at arbitrary resolutions? Real world only please -- I am aware of the tools available to do this for, say, KSP.
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### What is the delta-V equivalent to cross the Kármán line in vertical (suborbital) flight?

...or, well, for a typical example - how much delta-V does New Shepard carry? For orbital launches, there's the ~1km/s estimate to overcome drag and gravitational losses on orbital launches; 8km/s of ...
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### How to calculate the delta-v necessary for a suborbital “transfer” of ice from Mars' pole to equator?

I have a big chunk of water ice that needs to go from (say) one of Mars's poles to its equator. Neglecting the atmosphere, how would you calculate the delta-v necessary for this trajectory, and what ...
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### How does the delta v for leaving Earth orbit change in different directions from the Earth?

Inspired by this answer on How to intuitively explain that reaching geostationary orbits consume more Delta V than escape orbits?, which states Move to the edge of the Hill sphere, sit at Earth-...
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### How to intuitively explain that reaching geostationary orbits consume more Delta V than escape orbits?

Studying again orbital maneuvers, I found the following plotting the cost of a Hohmman transfer between coplanar circular orbits (black line), in terms of $\Delta V$ against the orbit ratio $r_f/r_i$. ...
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### How does the delta V to reach and orbit L4 and L5 compare to entering orbit around the Moon?

The L4 and L5 Lagrange points, 60 degrees in front of and behind the Moon in its orbit around Earth, orbit at the same speed as the Moon. But when a spacecraft flies to the Moon, the gravity of the ...
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### Budgeting delta-v for atmospheric drag when orbit is elliptical?

I'm trying to calculate the delta-V budget to maintain a generic elliptical orbit. Looking at the atmospheric drag losses I can only find equations that calculate delta-V loss for circular orbits. ...
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### Energy consumption for travelling to the Moon vs. to Mars

I just finished reading Clarke's "Prelude to Space". In chapter XXVII the character Taine gives a talk where he states It sounds paradoxical, but it's easier to make the forty-million-mile journey ...
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### Where is the optimal location to launch payloads to outer space?

Imaginary scenario: The US, Russia, China, Europe, India, and all the private space companies in between combine resources for a sustained space exploration program beyond Earth. They can choose any ...
If we assume that we have a given launcher that is able to produce a $\Delta v$ of 10km/s at sea level takeoff, and is able to reach an LEO of 200km above sea level, what LEO altitude would that ...