Representation theory of the Galilean group to , and applying Hamilton's equations, we obtain the mass-velocity relation . The hypersurface is parametrized by this velocity In . Consider the stabilizer of a point on the orbit, (), where the velocity is . Because of transitivity, we know the unitary irrep contains a nontrivial linear subspace with these energy-momentum eigenvalues. (This subspace only exists in a rigged Hilbert space, because the momentum spectrum is continuous.) The subspace is spanned by , , and . We already know how the subspace of the irrep transforms under all operators but the angular momentum. Note that the rotation subgroup is
Propellant mass fraction important role in the rocket equation: Where formula_10 is the ratio of final mass to initial mass (i.e., one minus the mass fraction), formula_11 is the change in the vehicle's velocity as a result of the fuel burn and formula_12 is the effective exhaust velocity (see below). The term effective exhaust velocity is defined as: where "I" is the fuel's specific impulse in seconds and "g" is the "standard acceleration of gravity" (note that this is not the local acceleration of gravity). To make a powered landing from orbit on a celestial body without an atmosphere requires the same mass