import pykep as pk
earth = pk.planet.jpl_lp("earth")
mars = pk.planet.jpl_lp("mars")
dep = pk.epoch(10000)
arr = pk.epoch(10300)
r1, _ = earth.eph(dep)
r2, _ = mars.eph(arr)
tof = (arr.mjd2000 - dep.mjd2000) * 86400
lamb = pk.lambert_problem(r1, r2, tof, pk.MU_SUN)
lamb.get_v1()[0](14997.23930157594, -27871.526640838634, -813.6013109250553)