Global constants#
In pykep the access a number of common constants are provided for convenience. The user can overwrite their values if needed. These constants are not used in the pykep internals, they are only provided for convenience for the user to instantiate / use the various pykep objects and functionalities.
Constant’s Name |
Symbol in pykep |
Units |
Value |
|---|---|---|---|
Astronomical Unit |
pykep.AU |
\(m\) |
1.495978707e+11 |
Cavendish constant |
pykep.CAVENDISH |
\(\frac{m^3}{sec^2 kg}\) |
6.67430e-11 |
Sun’s gravitational parameter |
pykep.MU_SUN |
\(\frac{m^3}{sec^2}\) |
1.32712440041279419e20 |
Earth’s gravitational parameter (JPL DE440) |
pykep.MU_EARTH |
\(\frac{m^3}{sec^2}\) |
3.98600435507e+14 |
Moon’s gravitational parameter (JPL DE440) |
pykep.MU_MOON |
\(\frac{m^3}{sec^2}\) |
4.902800118e+12 |
Earth’s velocity |
pykep.EARTH_VELOCITY |
\(\frac{m}{sec}\) |
29784.691831696804 |
Earth’s radius |
pykep.EARTH_RADIUS |
\(\frac{m}{sec}\) |
6378137.0 |
Earth’s \(J_2\) |
pykep.EARTH_J2 |
– |
0.00108262668 |
CR3BP: Moon-Earth parameter |
pykep.CR3BP_EARTH_MOON |
– |
0.01215058439470971 |
BCP: Moon-Earth parameter (same as for the CR3BP) |
pykep.BCP_EARTH_MOON |
– |
0.01215058439470971 |
BCP [SimoGomezJM95]: Scaled mass of the Sun |
pykep.BCP_MU_S |
– |
328900.55970856483 |
BCP [SimoGomezJM95]: Scaled Sun–(Earth + Moon) distance |
pykep.CR3BP_RHO_S |
– |
3.88811143E2 |
BCP [SimoGomezJM95]: Scaled angular velocity of the Sun |
pykep.CR3BP_OMEGA_S |
– |
-9.25195985E-01 |
Seconds in one day |
pykep.DAY2SEC |
– |
86400.0 |
Days in one second |
pykep.SEC2DAY |
– |
1.1574074074074073e-05 |
Degrees in one radians |
pykep.RAD2DEG |
– |
57.29577951308232 |
Radians in one degree |
pykep.DEG2RAD |
– |
0.017453292519943295 |
Days in one year |
pykep.YEAR2DAY |
– |
365.25 |
Years in one day |
pykep.DAY2YEAR |
– |
0.0027378507871321013 |