VSAT index

How to make inclinometer

Inclined orbit operation

Geo orbit repositioning

O3b orbit

Design a sat beam

Focal length of parabola

List of geo satellites

2-line element calculation

Convert TLE to Charlie

Elliptical orbit height and speed

Sub reflector adjustment

Use rear side struts

Antenna anti-icing

Satellite link budget

Site shielding

Dish distortion

Antenna panel alignment

Mass and weight

Station keeping

Circular orbit height speed

Delta V calculator for LEO/MEO/GEO orbit injection

Transfer orbit inclination (or launch site latitude) Initial circular orbit height, same as transfer orbit perigee altitude (bottom) Transfer orbit apogee altitude (top)

Initial, circular, low earth orbit Velocity
Period of initial low earth orbit
Injection into elliptical transfer orbit delta V
Transfer orbit initial velocity
Transfer time from perigee to apogee
Transfer orbit final velocity at apogee
Injection into circular orbit delta V (inc+circ)
Final circular orbit Velocity
Final orbit period
Final orbit geo drift rate

Low earth orbit mass (inc fuel) Specific Impulse of perigee thruster
Fuel used at perigee injection
Transfer orbit Mass

Transfer orbit mass Specific Impulse of apogee thruster
Fuel used at geo injection
Beginning of Life GEO Mass

Enter your initial low earth circular orbit inclination and height.

Example inclinations: Based on latitudes of launch sites:
Sea Launch 0 deg, Kourou 5.23 deg, Kennedy 28.5 deg, Tyuratam 46 deg.

Example initial low parking orbit heights: 200 km or 300 km.

Final circular orbit height for geostationary orbit satellites is 35786.13 km
O3b orbit height is medium earth orbit (MEO) at 8063km.

If interested, enter your low earth circular orbit  'off-the-rocket' orbit mass (inclusive of spacecraft fuel) and specific impulse of the perigee motor.
Specific impulse of solid fuel motors is about 285 to 295 s.
Liquid bi-propellant systems give a specific impulse of about 310 s.
Ion thrusters, specific impulse = 1000 - 10000 s (approx)

Calculation results are the delta Vs to get from circular LEO orbit to elliptical transfer orbit and and from transfer orbit to geo orbit and fuel used.


These are approximate calculations.  Typical launch sequences may involve direct injection into a transfer orbit with probably a small reduction of the inclination at the same time.  The calculations assume impulse (short time) burns so that the spacecraft does not move significantly during the burn time.  If it takes longer you would do better to split the burn into a sequence of shorter burns done at the sequential apogees (about 12 hours apart).  You may wish to start the orbit life with a small 'negative' inclination so it settles down of its own accord by the time you want to commence service. Ion thrusters have very high specific impulse but very low thrust so are better suited to station keeping rather than transfer orbit manoeuvres. If used for GEO orbit injection the use of ion thrusters give a very substantial reduction in cost to GEO orbit, but at the penalty of a very long time taken to get there.  A typical apogee motor with have a thrust of 490 N, while an ion thruster will have a thrust of 0.05 N, so it might take perhaps seven to ten months to raise the orbit using ion thruster.

Modified to allow the possibility of using different specific impulses for transfer orbit and geo injection, illustrating the benefit of ion thrusters, albeit with the very long thrusting times, measured in months.

8-9 July 2019: Modified by adding the full period for the initial low circular and time for the elliptical transfer.

This calculator is only for educational purposes.  The results of may be in error and should not be used for orbital manoeuvres or the navigation of real spacecraft.

If anyone uses this page and is able to do the calculations independently themselves please tell me where I am wrong.

Design your own rocket.

Do you need a rocket ?  Here is a good educational tool to help you specify/design a rocket and get a price: https://www.rocketbuilder.com/start/configure

Any problems, suggestions for improvements or comments, please e-mail me Eric Johnston
This calculator is copyright (c) 2012 Satellite Signals Ltd.

Page started 30 Aug 2012. Amended 18 Nov 2018 HTML5, 8-10 July 2019 (added transfer orbit time and LEO period), 5 April 2021, 27 Feb 2022, 14 Dec 2023.