**2.1 Orbital transfer delta-V**

Phobos and Deimos exploration and exploitation methods have been studied for many decades: landers, flybys, etc. [6–11]. While landers have been assessed in the past, this chapter will focus on the orbital transfer delta-V requirements and orbital transfer vehicle designs that would allow the 2 moons' exploration and exploitation.

The orbital missions are controlled by the delta-V or change of velocity needed for the orbit transfers. Both high-thrust missions and low-thrust missions were assessed. The high-thrust delta-V values were computed with a standard Hohmann transfer Equations [12]. The values for the low-thrust delta-V were calculated using the Edelbaum equation [13]. The nominal semi major axes for Phobos and Deimos are 9,378 and 22,459 km [2].

In all cases, the delta-V values are for round trip missions. There are 5 trips that were assessed: Phobos to Deimos, Phobos to areosynchronous Mars orbit (AMO), Phobos to 100,000 km altitude, Deimos to AMO, and Deimos to 100,000 km altitude.

**Figure 1** and **Table 1** provide the round trip delta-V for Phobos and Deimos missions. Both high thrust and low thrust delta-V values are presented. Due to the typical gravity losses with high thrust propulsion systems, a 20% delta-V increase

#### **Figure 1.**

*OTV delta-V, Phobos and Deimos orbital transfer missions.*


**193**

used [12]:

*Martian Moons and Space Transportation Using Chemical and Electric Propulsion Options*

was added; no added losses were imposed on the low thrust systems. In **Figure 1**, the Phobos to 100,000 km low thrust delta-V was 2.99 km/s. The Phobos to Deimos low thrust delta-V was 1.58 km/s. At Deimos, the highest round trip delta-V is for the Deimos to AMO transfer was 0.24 km/s. The round trip low-thrust transfer to

High thrust chemical propulsion, using oxygen/hydrogen rocket engines is a natural choice [14]. If indeed water were available on the Martian moons, it would make sense to capitalize on that water resource, and finally producing rocket-purity

Electric propulsion systems with either ion or Hall thrusters are potential options. Xenon or other inert gases are the typical choice for such thrusters. Using hydrogen as an electric propulsion propellant with a pulsed inductive thruster (PIT)

Several advanced propulsion options for Martian moon transportation, exploration, and industrialization were investigated. Chemical propulsion and nuclear electric propulsion (NEP) with a range of power levels for Martian orbital transfer vehicles (OTVs) were assessed. Design parameters, vehicle mass scaling equations, and summaries of these analyses are presented; Mass scaling equations were developed for the

In sizing the chemical propulsion OTVs, a vehicle mass scaling equation is used [14]:

*m dry stage m dry coefficient x m p a fixed* ( , , ) = ( ) ( ) + ( ) (1)

O2/H2 chemical propulsion and the nuclear electric propulsion systems [14].

m(dry, stage) = the stage dry mass, including residual propellant (kg). m(dry, coefficient) = the B mass coefficient (kg of tank mass/kg of usable

system masses. The Martian moon OTVs were single-stage vehicles.

The chemical propulsion OTVs had a B coefficient of 0.4. The fixed mass was 500 kg. The fixed mass includes guidance systems, adapters and reaction control

The NEP OTV mass and trip time were estimated based on the power system and the propulsion system design [14]. The following dry mass scaling equation was

*m dry stage NEP alpha x P x m p m fixed* ( . , ) =+ + 0.05 ( ) ( ) (2)

*DOI: http://dx.doi.org/10.5772/intechopen.96717*

100,000 km required only 1.42 km/s.

**3. Propulsion options**

oxygen and hydrogen.

has also been proposed.

where

propellant. mass).

*3.1.2 NEP OTV sizing*

**3.1 Advanced propulsion options**

*3.1.1 Chemical propulsion OTV sizing*

m(p) = usable propellant mass (kg). a(fixed) = chemical OTV fixed mass (kg).

#### **Table 1.**

*Orbital transfer mission options (for the high thrust options, the delta-V is increased by 20%).*

*Martian Moons and Space Transportation Using Chemical and Electric Propulsion Options DOI: http://dx.doi.org/10.5772/intechopen.96717*

was added; no added losses were imposed on the low thrust systems. In **Figure 1**, the Phobos to 100,000 km low thrust delta-V was 2.99 km/s. The Phobos to Deimos low thrust delta-V was 1.58 km/s. At Deimos, the highest round trip delta-V is for the Deimos to AMO transfer was 0.24 km/s. The round trip low-thrust transfer to 100,000 km required only 1.42 km/s.
