# How to find the TLE (two-line element) for a satellite using orbital parameters?

Can I calculate the two-line element for a new satellite using the orbital parameters? How do I calculate mean motion for a satellite?

Is BSTAR drag term in TLE same for all satellites? If not, then how do I calculate BSTAR drag term?

• Can you clarify which orbital elements you already have? Jun 27 '16 at 17:47

$$n = \frac{1}{P}$$ This gives $n$ in as a revolutions per unit time.
The b-star is essentially empirical. One could calculate it as $$B = \frac{C_d A}{m}$$ $$B^* = B \rho / 2$$ with $m$ as mass, $C_d$ a drag coefficient one might get from CFD, $A$ the cross-sectional area, $\rho$ density of atmosphere. In practice this is determined from curve fitting with multiple observations, so it can end up incorporating multiple pertubative effects, not just drag. (In fact, it can be negative!) For a small near-earth satellite setting it to zero often suffices.