Nº CARGO/ RECOMENDACIONES ENE FEB MAR FIRMA SERVIDORES RESPONSABLES

Figure 22: Operational view of Short Stay Lunar Mission

Short Stay Lunar Missions have a crew of three astronauts and two of these astronauts spend approximately two days on the lunar surface.

A Crew Operations Vehicle (COV) containing three astronauts is launched into low Earth orbit on a man-rated launch vehicle such as a man-rated heavy EELV. A Lunar Lander (LL) is launched into LEO separately using an STS-derived launch vehicle.

Launch vehicles are chosen based on mass estimates documented in Appendix 9.3.

The COV and LL dock in LEO and transit to lunar orbit together using cryogenic chemical propellant. Once in lunar orbit, two crewmembers transfer to the LL, undock from the COV and descend to an equatorial landing site on the near side of the Moon using cryogenic chemical propellant. One crewmember remains in the COV in lunar orbit.

The astronauts on the lunar surface will live in the LL for approximately two days and

Upon the conclusion of the surface stay, the two astronauts ascend to lunar orbit in the LL using cryogenic chemical propellant and dock with the COV. One person is left in the COV as a safety measure for the basic technology demonstration; in case the LL fails to dock with the COV, the astronaut in the COV can manually maneuver to dock with the LL. Then, the astronauts transfer to the COV, undock with the LL, and initiate the return trip using cryogenic chemical propellant. The COV performs a ballistic re-entry, returning the astronauts to Earth.

4.2.4.2 Medium Stay Mission

Figure 23: Operational view of Medium Stay Lunar Mission

Medium Stay Lunar Missions have a crew of three astronauts and use the same spacecraft forms as the Short Stay Lunar Missions. However, there are three differences between the Short and Medium Stay Missions: the LL is pre-positioned in lunar orbit using electric propulsion, all astronauts transfer to the LL to descend to the lunar surface, and the astronauts stay on the lunar surface for one week.

The justification for pre-positioning the Lunar Lander in lunar orbit before the arrival of the crew is to test the technology of pre-positioning essential mission cargo utilizing electric propulsion technology. While not providing a major mass savings for missions

to the Moon, the capability of pre-positioning will allow for dramatic mass savings for missions to Mars. This is one of the ways the Moon can be used as a testbed for future missions to Mars.

First, a LL is launched into LEO alone using an STS-derived launch vehicle. Electric propulsion is then used to pre-position the LL in lunar orbit. Later, a COV containing the three astronauts is launched into low Earth orbit using an EELV (Delta IV Heavy). The COV transits to lunar orbit together using cryogenic chemical propellant. Once in lunar orbit, the COV docks with the pre-positioned LL, the three crew members transfer to the LL, undock from the COV and descend to non-equatorial landing sites on the near side of the Moon using cryogenic chemical propellant. No crewmembers remain in the COV in lunar orbit; it is assumed LL ascent was proven to be reliable during the Short Stay Lunar Missions.

The astronauts on the lunar surface will live in the LL for approximately one week and explore the landing site using an “open-air” rover to aid mobility within walking distance from the LL; EVA will have high science capabilities including research in some of the areas outlined in Section 3.2.1: Scientific Knowledge.

Upon the conclusion of the surface stay, the three astronauts ascend to lunar orbit in the LL using cryogenic chemical propellant and dock with the COV. The astronauts transfer the COV, undock from the LL, and initiate the return trip using cryogenic chemical propellant. The COV performs a ballistic re-entry, returning the astronauts to Earth.

4.2.4.3 Long Stay Lunar Mission

6 month stay

Earth orbit Moon orbit

Earth surface Moon surface

Electric propulsion

Modern Command Module # 1 Surface Habitation Module Crew Operations Vehicle

Service Module # 1 Lander # 2 Lander # 1 Habitation Module

LEO Reentry

Figure 24: Operational view of Extended Stay Lunar Mission

Extended Stay Lunar Missions have a crew of six astronauts and require a pre-positioned surface habitat for the crew to live in for up to six months. A crew of six is used for this mission since future missions to Mars will have crew sizes of six.

It is important to mention that the increased complexity of the Extended Stay Lunar mission is essential for two major reasons. First, the increased complexity results from the multitude of technologies being tested in preparation for missions to Mars. Second, the increased complexity is used to return even greater amounts of knowledge back to Earth. This is made possible from a crew living on the Moon for an extended period of time in a location that is highly valuable from a knowledge point of view.

First, a surface habitation module (SHM) is launched into LEO possibly using two STS-derived launch vehicles. The SHM is then pre-positioned on the lunar surface, using electric propulsion for the transit to lunar orbit, and cryogenic chemical propulsion for the descent. Second, two Lunar Landers are launched into LEO separately using STS-derived launch vehicles. Electric propulsion is then used to pre-position the Lunar Landers in lunar orbit. One module of the habitation module (HM) is launched into LEO along with one of the Lunar Landers. Third, a COV containing three astronauts is launched into LEO using a man-rated launch vehicle such as a man-rated EELV. The same launch vehicle also contains a Modern Command Module (MCM). Each of these

vehicles contains three astronauts. The COV docks with the HM and MCM, the crew of the MCM transfers to the HM, and the MCM undocks.

The docked COV and HM then transit to lunar orbit using cryogenic chemical propellant.

In lunar orbit, the pre-positioned LL1 docks with the COV and HM, the three crewmembers transfer to the LL1, the LL1 undocks from the COV and descends to the pre-positioned SHM on the far side or pole of the Moon using cryogenic chemical propellant. Likewise, the second pre-positioned Lander, LL2 then docks with the COV and HM and transfers the crew to the SHM. No crewmembers remain in the COV in lunar orbit.

The astronauts on the lunar surface will transfer from the Lunar Landers to the SHM for a surface stay of approximately six months. The semi-permanent base allows for extensive science capabilities, possibly including but not limited to Moon-based observatories, greenhouse technology demonstrations for closed-loop life support, and nuclear power production. A habitable, pressurized rover for overnight field trips will aid surface mobility.

At the end of the surface stay the six astronauts ascend to lunar orbit in the two Lunar Landers. Each Lander individually docks with the COV and HM. After each docking, three astronauts transfer to the COV and then the COV and Landers undock. Finally, the astronauts initiate the return trip to Earth in the COV using cryogenic chemical propellant. The COV and HM use aerobraking to establish Earth orbit and then dock with the MCM. Three astronauts transfer to the MCM to return to Earth. The other three astronauts remain in the COV, undock from the HM, and return to Earth.