Electric Sail Propulsion Modeling and Mission Analysis
IEPC-2007-352
Presented at the 30th International Electric Propulsion Conference, Florence, Italy
September 17-20, 2007
Pekka Janhunen∗
Finnish Meteorological Institute, FIN-00101 Helsinki, Finland
Giovanni Mengali†and Alessandro A. Quarta‡
University of Pisa, I-56122 Pisa, Italy
Abstract: The electric sail1,2 is a new propulsion concept that uses the solar wind
momentum flux for producing thrust. Like the more conventional solar sail, it allows a
spacecraft to perform high-energy orbit transfers without a need for reaction mass. The
electric sail could accelerate small (10-100 kg) payloads to substantial final speeds, larger
than that are possible with conventional (either chemical or electric) propulsion systems.
It could also provide a lightweight propulsion alternative for larger payloads (100-1000 kg).
With reference to the latter choice, in this paper we provide quantitative estimates for
optimized Earth-Mars transfers for both an electric sail and a solar electric propulsion
(SEP) system. To facilitate the comparison we use the same specific power assumption for
both systems. For this case study it is found that the electric sail and SEP performance
are rather similar. The electric sail has higher payload fraction than SEP, whereas SEP
tends to have somewhat shorter mission times.
Nomenclature
α
= angle between thrust and the Sun-spacecraft line (coning angle)
β0
= initial specific power of SEP system (kg/W)
e
= electron charge
ε0
= vacuum permeability
K
= numerical coefficient (nominally 3.09)
λDe = solar wind Debye length
me = electron mass
mp = proton mass
mf = spacecraft final mass
m0 = spacecraft initial mass
n0
= solar wind plasma density
r0
= two times solar wind Debye length
rw
= wire radius
r∗w
= effective electric radius of tether
Te
= solar wind electron temperature in energy units
θ
= angle between radial and tether direction
v
= solar wind speed
∗Senior Researcher, Space Research, pekka.janhunen@fmi.fi.
†Associate Professor, Department of