Loading
/custom-emojis/emojis/contour-map.png
Templates
📚
Articles & Resources
📖
Guides & Support
🎖️
Bounty Program
🌵
CalcTree
Orbital velocity and period are an integral part of space mission design that is affected by key parameters such as the apogee and perigee of the spacecraft's orbit. This orbital mechanics calculator can help you the orbital velocity and period of a spacecraft in any circular or elliptical orbit around the Earth.

Calculation

Inputs



Apogee Height
:700.00km



Perigee Height
:700.00km

Constants


Radius of Earth
:6378.1km



Gravitational Parameter of Earth
:398600m3/s2



Primary outputs



Orbital Velocity (Apogee)
:7.50km/s



Orbital Velocity (Perigee)
:7.50km/s



Orbital Period
:1.65hours



Eccentricity
:0.0


Explanation

Perigee and apogee explanation

Perigee and apogee are terms used in orbital mechanics to describe the closest and farthest points, respectively, between an object and the primary body it orbits. Perigee represents the point of closest proximity, while apogee denotes the farthest distance in the object's orbit.

Additional equations and outputs

The radii of the apogee and the perigee of the orbit is found using:

R=RE+AR = R_E + A

R=RadiusofApogee/Perigee(km)RE=RadiusofEarth(km)A=AltitudeofApogee/Perigee(km)R = Radius\,of\,Apogee/Perigee\,(km)\\R_E=Radius\,of\,Earth\,(km)\\A = Altitude\,of\,Apogee/Perigee\,(km)\\



RA
:7,078.10km



RP
:7,078.10km

The semi-major axis of the orbit is found using:

SMA=RA+RP2SMA=\frac{R_A+R_P}{2}
Where:

SMA=SemiMajorAxis(km)SMA=Semi-Major\,Axis\,(km)



SMA
:7,078.10km

The specific energy of the spacecraft in orbit is found using:

ϵ=GP2SMA(km2/s2)\epsilon=-\frac{GP}{2*SMA}\,(km^2/s^2)
Where:

ϵ=specificenergy(km2/s3)GP=GravitationalParameter\epsilon = specific \: \:energy \: \: (km^2/s^3) \\ GP=Gravitational \: \: Parameter


Specific energy (km2/s2)
:-28.16


The orbital velocity of the spacecraft at any point in the orbit is found using:

vorbital=2(GPR+ϵ)(km/s)v_{orbital}=\sqrt{2*(\frac{GP}{R}+\epsilon)} \,\,(km/s)


Orbital Velocity (Apogee)
:7.50



Orbital Velocity (Perigee)
:7.50

The orbital period in hours of the spacecraft is found using:

T=2π(SMA3GP)13600(Hours)T =2\pi (\sqrt{\frac{SMA^3}{GP}})\frac{1}{3600} \,\,(Hours)


Orbital Period
:1.65hours



Related Resources

If you liked this, check out our other articles and resources!
  1. Check out our full calculation template library
  2. More physics calculators and explanations
  1. Centre of Gravity Calculator
  1. Centre of Mass Calculator
  2. Orbital Mechanics Calculator
  3. Radius of Gyration In Structural Engineering