## SubL1Accel:

```--------------------------------------------------------------------------
Find a sail acceleration to maintain a Sub-L1 station.
Assumes a circular orbit of the Earth-Moon barycenter at 1 AU.
The angles theta and phi measure the displacement of the sail from the
Sun-Earth line.

Note: Unlike Carl Sauer's plotted results, a nonzero theta or phi seem to
push the acceleration completely off the radial direction.

Since version 7.
--------------------------------------------------------------------------
Form:
[a, a0, alpha] = SubL1Accel( dX, theta, phi )
--------------------------------------------------------------------------

------
Inputs
------
dX         Distance from the Earth, AU

-------
Outputs
-------
a          Sail acceleration at station
a0         Characteristic accel, km/s2
alpha      Sail normal angle

--------------------------------------------------------------------------
Reference: Carl G. Sauer, The L1 Diamond Affair. 14th AAS/AIAA Space Flight
Mechanics Conference. Maui, Hawaii, 2004. AAS 04-278
--------------------------------------------------------------------------
```

## Children:

```Math: Linear/Mag
Math: Linear/Unit
```