The slingshot effect can be used to give a boost of speed/energy if a vehicle goes past a planetary or lunar body, it is possible to pick up (or lose) some of that body's orbital speed relative to the sun or another planet.Īnother effect is the Oberth effect-this can be used to greatly decrease the delta-v needed, because using propellant at low potential energy/high speed multiplies the effect of a burn. In other cases, boosting up to a relatively high altitude apoapsis gives low speed before performing the plane change and this can give lower total delta-v.
#Kerbal space program dv map free#
However, these plane changes can be almost free in some cases if the gravity and mass of a planetary body are used to perform the deflection. The velocity of the vehicle needs substantial burns at the intersection of the two orbital planes and the delta-v is usually extremely high. In that case there is an additional delta-v necessary to change the plane of the orbit.
![kerbal space program dv map kerbal space program dv map](https://i.ytimg.com/vi/Hy5TfryOl60/maxresdefault.jpg)
In some cases a bi-elliptic transfer can give a lower delta-v.Ī more complex transfer occurs when the orbits are not coplanar. The simplest delta-v budget can be calculated with Hohmann transfer, which moves from one circular orbit to another coplanar circular orbit via an elliptical transfer orbit. A key goal in designing space-mission trajectories is to minimize the required delta-v to reduce the size and expense of the rocket that would be needed to successfully deliver any particular payload to its destination. The Tsiolkovsky rocket equation shows that the delta-v of a rocket (stage) is proportional to the logarithm of the fuelled-to-empty mass ratio of the vehicle, and to the specific impulse of the rocket engine.
![kerbal space program dv map kerbal space program dv map](https://i.imgur.com/AAGJvD1.png)
2.6 Delta-vs between Earth, Moon and Mars.
#Kerbal space program dv map windows#
Because the delta-v needed to achieve the mission usually varies with the relative position of the gravitating bodies, launch windows are often calculated from porkchop plots that show delta- v plotted against the launch time. An atmosphere can be used to slow a spacecraft by aerobraking.Ī typical delta- v budget might enumerate various classes of maneuvers, delta- v per maneuver, and number of each maneuver required over the life of the mission, and simply sum the total delta- v, much like a typical financial budget. In the absence of an atmosphere, the delta- v is typically the same for changes in orbit in either direction in particular, gaining and losing speed cost an equal effort. Tables of the delta- v required to move between different space venues are useful in the conceptual planning of space missions. Also delta- v is additive, as contrasted to rocket burn time, the latter having greater effect later in the mission when more fuel has been used up. For example, although more fuel is needed to transfer a heavier communication satellite from low Earth orbit to geosynchronous orbit than for a lighter one, the delta- v required is the same. As input to the Tsiolkovsky rocket equation, it determines how much propellant is required for a vehicle of given mass and propulsion system.ĭelta- v is a scalar quantity dependent only on the desired trajectory and not on the mass of the space vehicle. It is calculated as the sum of the delta-v required to perform each propulsive maneuver needed during the mission. In astrodynamics and aerospace, a delta-v budget is an estimate of the total change in velocity ( delta- v) required for a space mission. That means the vessel can stop a 200 m/s descent with a 36 second burn.Delta- v in feet per second, and fuel requirements for a typical Apollo Lunar Landing mission. Subtract the gravity of Minmus and you have a remaining deceleration of about 5.5 m/s². A 10 ton vehicle with a LV-909 "Terrier" (60kN) engine has an acceleration of 60,000 / 10,000 = 6 m/s². So how do you calculate the acceleration of a vessel? Simply divide the thrust by the mass. That means the more thrust you have, the closer to the surface you can dare to start your break maneuver, which means you will be closer to the ideal delta-v budget. The later you start your deceleration burn, the less delta-v you need. How much more acceleration? That depends on how efficient you want to land. But to land, you need to reduce the speed to zero before surface contact, so you need more acceleration. When you have a craft which can accelerate at least that fast, it is capable to hold its speed constant while descending. You can look up the surface gravity acceleration of a body in the tracking station or on the wiki. But he didn't say anything about how much thrust you need.
![kerbal space program dv map kerbal space program dv map](https://i.imgur.com/CEZS1.png)
To get from orbit to ground you need at least as much delta-v as the orbital speed at ground level. Tgharold answered pretty well how much delta-v you need in the ideal case.