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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31
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7answers
12k views

How could a 90 m/s delta-v be enough to commit the space shuttle to landing?

Wikipedia claims (although with no citation) that in order to make the space shuttle land, an initial powered delta-v of 322 km/h was applied in orbit, retrograde to the shuttle's orbit. 322 km/h is ...
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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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1answer
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Delta-V of Starlink Satellites

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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1answer
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Is the ideal transfer between two arbitrary planar orbits always a bi-tangential ellipse?

I was reading Hollister David's short paper on bi-tangential transfers. The example he uses is a transfer between a planar circular and an elliptical orbit. I am wondering: Is an ideal, that is, the ...
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Is this a correct understanding of Tsiolkovsky's rocket equation?

When I graph the rocket equation, substituting arbitrary values for v(exhaust) and m1, so m0 because m1 - m0, the graph implies that increasing propellant mass past a certain point does not increase ...
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How much delta-v can we squeeze out of a gravitational slingshot and what factors limit it?

A lot of space probes use gravity assists from various space objects to boost their speed and save on propellant requirements. On what factors does the increase of delta-v depend? My guesses are: ...
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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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1answer
550 views

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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Delta-V chart mathematics

Could someone explain me the mathematics behind the Delta-V charts one can find on internet such as:                 &...
17
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1answer
375 views

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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How to calculate Delta V for lunar flyby

As I understand the idea of a lunar flyby, you can pass a spacecraft by the far side of the moon without having to burn fuel to decrease your momentum and get to LLO (Low Lunar Orbit). But it seems ...
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1answer
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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 ...
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Calculating solar system escape and and sun-dive delta V from lower Earth orbit

According to http://en.wikipedia.org/wiki/Escape_velocity at the Earth/Moon distance from the sun, the escape velocity is 42.1 km/s. According to http://en.wikipedia.org/wiki/Earth the average ...
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Do you need 0 km/s velocity to crash into the sun?

I was reading a popular thread about the delta-v required to escape the solar system compared to the delta-v required to crash into the sun. I get it: the earth itself already has a high speed (29.7km/...
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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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1answer
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Range of travel time between particular planets using the Interplanetary Transport Network/Interplanetary Superhighway?

I understand the Interplanetary Transport Network allows for travel at low speeds between different planets in the solar system using very little energy. Is there flexibility in how long it would take ...
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Can a miniature Saturn V get to the moon and back?

If the Saturn V rocket along with its Apollo spacecraft was miniaturized, for example to 1/72 scale so it was five feet tall, could it still perform a moon landing like the Apollo missions and get ...
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How can delta-v and aerobraking as shown in this chart be explained?

The following diagram was included in Rikki-Tiki-Tavis' answer to this fine question of a few hours ago. I am hoping somebody can explain some of the questions I have about this data. It shouldn't ...
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1answer
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Minimum Delta V to a staging area in cislunar space for a vertical space gun

Space guns have a lot of confounding factors for getting to LEO. The projectile must be a rocket capable of large delta v in order to circularize the orbit. Then, giving more sideways velocity ...
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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. ...
13
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1answer
485 views

How much delta-v can be achieved by venting the ISS atmosphere?

A sort-of follow-up to What do the astronauts do whilst the air-lock cycles? The ISS fact-sheet writes to say Pressurized Volume: 32,333 cubic feet (916 cubic meters) Elsewhere on the stack are ...
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1answer
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Delta-v of deep space maneuvers in deep space missions like Voyager or Pioneer

What are typical delta-v for deep space maneuvers, used by deep space missions to outer planets or for "interstellar missions" ? For example, Voyager 1 now has 17 km/s speed relative to the Sun. What ...
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How useful is the Interplanetary Transport Network?

Wikipedia summarizes the Interplanetary Transport Network/Interplanetary Superhighway fairly succinctly, although it's pretty vague to someone who doesn't know what's going on: The Interplanetary ...
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1answer
566 views

Are ion thruster trajectories classified as brachistochrones?

Usually, when performing trajectory optimizations for chemical rockets, the limiting factor is the $\Delta v$ budget. That means velocity change is the optimization factor, with things like transfer ...
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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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Dragon 2 Propellant Capacity

According to its wikipedia article, the Dragon 2 is powered by 8 SuperDraco engines. And according to the SuperDraco's article, each one of them can store up to 1,388kg of propellant at an Isp of 240s....
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1answer
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Delta-v to move from GEO to GEO

To move a satellite in geostationary orbit, 166°55′E, to the antipode, 13° 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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2answers
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Delta-V to Low Mars Orbit

I'm making a Mars probe in Kerbal Space Program Real Solar System, and I have 13 km/s of Delta-V in the lifter itself. I have a cryogenic second stage with a KVD-1 engine, it has 7.36 km/s of Delta-V, ...
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1answer
860 views

Moon orbit station-keeping delta-V budget

I am looking for examples of station-keeping delta-V budgets from lunar orbiters to verify the results of an orbital-perturbations programm that I wrote for my master thesis. Any indication on where ...
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1answer
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What spacecraft has had the greatest total propulsive delta-v?

How fast is fuel escaping a rocket for it to reach the escape velocity 11 km/s? was an active and well-received discussion! It's always exciting when we first realize that a rocket can go much faster ...
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Lambert's problem solution: optimal transfer time

I'm solving the Lambert's problem, and already have written a program, which solves the BVP using Shooting method and computes ...
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1answer
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Could any modern launch vehicle have put Ulysses in it's polar heliocentric without going to another planet first?

This answer to Why aren't satellites launched into a Polar LEO to get into Polar Heliocentric Orbit? leaves me wondering if it could be done today without the trip to Jupiter. Could a replica of the ...
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1answer
138 views

Is there a list of space exploration mission ordered by “size”?

While playing KSP I came to realize 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 that ...
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How much energy is required to send a payload of 40 t from Earth's surface to LEO?

I am confused with energy requirement equations... Am I anywhere near with my following assumptions: $\Delta v$ from surface to LEO is 9000 m/s typical exhaust velocity $v_e$ = 4500 m/s and mass of ...
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1answer
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Why is “delta-v + $\sqrt{{v_E}^2 + C_3}$ where ${v_E}^2 = $11.19 km/s” the correct way to calculate total propulsive delta-v? Please show all work

There is one answer to What spacecraft has had the greatest total propulsive delta-v? and I can not understand how its numbers have been calculated. Response to comments does not seem forthcoming so I'...
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What would it cost to bring a 1 gram payload to the CMBR rest frame (i.e. Δv 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 368 ± 2 km/s relative to. Without considering the ...
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Are transfers between two orbits commutative?

Are the propellant mass and transfer time from orbit A to orbit B the same as from orbit B to orbit A, considering low-thrust propulsion? That is, in the case of dealing with Keplerian orbit ...
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How much harder is it to land on the Moon away from the equator and the poles?

If a ship enters orbit around the Moon's equator, any place on the equator is equally accessible and doesn't take long to get to. The ship passes over the same strip of land with each orbit. Equally, ...
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1answer
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How much delta v does it take to get to the Sun-Earth Lagrange 3 point?

How much delta v does it take to get to the Sun-Earth Lagrange 3 point? Also, Would higher delta-v allow a craft to get there much quicker? Would two hohmann transfer orbits be the most efficient ...
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1answer
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Could a Mars return mission go directly back to the ISS?

I was reading a FAQ on Mars missions when I came across the following snippet: NASA does have the rocket technology to get humans to Mars. However, current technology is not advanced enough to get ...
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1answer
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Maximum speed reachable by Saturn V

If we launch a Saturn V rocket from space (far away from Earth so that Earth's gravity has no effect on it) then what would be the maximum velocity achievable? How close could it get us to the speed ...
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2answers
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Is there an absolute limit to single stage ∆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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1answer
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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 transfer:...
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1answer
926 views

How do I calculate lowest possible mission delta V from Escape velocities?

The gravitational potential of an object around the sun, relative to some point far far away (from the sun), should be smaller zero and proportional to $V_{escape}^2$. Hence the speed one needs should ...
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4answers
556 views

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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Do any current ICBM's have the delta-V to target the sun?

Based on an XKCD comic, XKCD 1626 which has the image: Do any of the active duty ICBM's have the ability to actually target the Sun? Considering that the R-7 booster that is the basis used by Soyuz/...
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2answers
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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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1answer
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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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1answer
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How much delta-v does the Orion spacecraft have?

Orion is intended to transport astronauts around cis-lunar space. How much delta-v performance does it actually have?
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1answer
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How exactly do “commanded delta-v burns” work in practice? (e.g. OSIRIS-REx)

Reading this answer to Could the uncertain mass of the OSIRIS-REx sample affect the trajectory of the return capsule? I infer that traditionally deep space spacecraft are sent timed commands for burns ...