Delta-v budget (or velocity change budget) is a term used in astrodynamics and aerospace industry for velocity change (or delta-v) requirements for the various propulsive tasks and orbital maneuvers over phases of the space mission. Sample delta-v budget will enumerate various classes of manoeuvres, delta-v per manoeuvre, number of manoeuvres required over the time of the mission. In the absence of an atmosphere and landings where the ground is hit with some speed, the delta-v is the same for changes in orbit the other way around: gaining and losing speed cost an equal effort.
Launch/landing budget
- Launch to LEO — this not only requires an increase of velocity from 0 to 7.8 km/s, but also typically 1.5–2 km/s for atmospheric drag and gravity drag
- Re-entry from LEO — the delta-v required is the orbital manoeuvring burn to lower perigee into the atmosphere, atmospheric drag takes care of the rest.
Stationkeeping budget
| Maneuver |
Average delta-v per year [m/s] |
Maximum per year [m/s] |
| Drag compensation in 400–500 km LEO |
<25 |
<100 |
| Drag compensation in 500–600 km LEO |
< 5 |
< 25 |
| Drag compensation in > 600 km LEO |
|
< 7.5 |
| Station-keeping in geostationary orbit |
50 – 55 |
|
| Station-keeping in L1/L2 |
30 – 100 |
|
| Station-keeping in Moon orbit |
0 [1] – 400 |
|
| Attitude control (3-axis) |
2 – 6 |
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| Spin-up or despin |
5 – 10 |
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| Stage booster separation |
5 – 10 |
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| Momentum wheel unloading |
2 – 6 |
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Earth-Moon space budget
Delta-v needed to move inside Earth Moon system (speeds lower than escape velocity) in km/s The return to LEO figures assume that a heat shield and aerobraking/aerocapture is used to reduce the speed by up to 3.2 km/s. The heat shield increases the mass, possibly by 15%. Where a heat shield is not used the higher from LEO Delta-v figure applies.
[2] [3] [4]
Interplanetary budget
According to Marsden and Ross, "The energy levels of the Sun-Earth L1 and L2 points differ from those of the Earth-Moon system by only 50 m/s (as measured by maneuver velocity)."[6]
Delta-vs between Earth and Mars
Delta-v's in km/s for various orbital manuevers
[7][8] using conventional rockets. Red arrows show where optional aerobraking can be performed in that particular direction, black numbers give delta-v in km/s that apply in either direction. Lower delta-v transfers than shown can often be achieved, but involve rare transfer windows or take significantly longer, see:
fuzzy orbital transfers. Not all possible links are shown.
Abbreviations used
See also
References
External links
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Orbits |
| Types |
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Parameters |
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Classical orbital elements
<math>i\,\!</math> Inclination
<math>\Omega\,\!</math> Longitude of the ascending node
<math>e\,\!</math> Eccentricity
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<math>\omega\,\!</math> Argument of periapsis
<math>a\,\!</math> Semi-major axis
<math>M_o\,\!</math> Mean anomaly at epoch
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Other parameters
<math>v\,</math> True anomaly
<math>b\,</math> Semi-minor axis
<math>\epsilon\,</math> Linear eccentricity
<math>E\,</math> Eccentric anomaly
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<math>L\,</math> Mean longitude
<math>l\,</math> True longitude
<math>T\,</math> Orbital period
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| Maneuvers |
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Related
topics |
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| List of orbits |
