How many burns are involved in a Hohmann transfer between coplanar circular orbits with minimum delta-v?

• A. Three burns
• B. One burn
• C. Two burns
• D. Four burns

Answer: (C)

Two impulsive thrusts are all that is needed for a Hohmann transfer between coplanar circular orbits. The spacecraft first fires at the initial orbit to place itself on an elliptical transfer orbit that is tangent to the starting circle at periapsis. This burn raises the energy just enough to reach the target radius as the ellipse’s apogee. At that second point, a second burn circularizes the trajectory by matching the velocity to the final circular orbit. Any other plan would either require extra burns (three or more) or use a different transfer method, which isn’t the standard Hohmann approach. So, the minimum-delta-v Hohmann transfer involves two burns.