Vision and Voyages for Planetary Science in the - Solar System ...

of this mission and the Mars Sample Return Orbiter (see below) would be borne by the European Space
Agency, as part of their partnership with NASA to carry out the Mars Sample Return campaign.
• Mars Sample Return Orbiter—This is the third component of the Mars Sample Return
campaign. It includes a Mars orbiter, an Earth-entry vehicle, and a terrestrial sample handling facility.
The orbiter is designed to rendezvous with the sample launched into orbit by the Mars Sample Return
Lander’s ascent vehicle, then transfer this sample into the Earth-entry vehicle and return it to Earth. The
MSR Lander and the MSR Orbiter are deferred to the decade following 2013-2022 because of
programmatic balance and the need to execute MAX-C first. Again, the committee assumes that a
significant fraction of the combined MSR Lander and Orbiter costs would be borne by ESA.
• Mars Geophysical Network—The primary science objectives of this mission are to
characterize the internal structure, thermal state, and meteorology of Mars. The mission includes two or
more identical, independent flight systems, each consisting of a cruise stage, an entry system, and a lander
carrying geophysical instrumentation. Science data are relayed from each lander to an existing orbiting
asset to be transmitted back to Earth. Consideration of the Mars Geophysical Network is deferred to the
decade following 2013-2022 because of its lower scientific priority relative to the initiation of the Mars
sample return campaign.
• Titan Saturn System Mission—This mission addresses key science questions regarding
Saturn’s satellite Titan as well as other bodies in the Saturn system. The baseline mission architecture
consists of an orbiter supplied by NASA, and a lander and Montgolfière balloon supplied by ESA. These
components will examine Titan, concentrating on the prebiotic chemical evolution of the satellite. In
addition, in transit to Titan the mission will examine the plumes of Enceladus and take measurements of
Saturn’s magnetosphere. As discussed in Chapter 8, consideration of this mission is deferred to the
decade following 2013-2022 primarily because of the greater technical readiness of JEO. Its high
scientific priority, however, is especially noteworthy. Because the Titan Saturn System Mission is a
particularly strong candidate for the future, continued thorough study of it is recommended.
• Neptune System Orbiter and Probe—If unforeseen circumstances were to make it impossible
to begin the Uranus Orbiter and Probe mission on the schedule recommended above, Neptune could
become an attractive alternate target for most ice giant system science. The committee’s mission studies
indicate, however, that significant hurdles remain in the area of aerocapture or other mission-enabling
technologies for a Neptune Orbiter and Probe to be feasible at a reasonable cost.
While consideration of the missions listed above is deferred to the following decade, technology
investments must be made in the decade 2013-2022 in order to enable them and reduce their costs and
risk. In particular, it is important to make significant technology investments in the Mars Sample
Return Lander, Mars Sample Return Orbiter, Titan Saturn System Mission, and Neptune System
Orbiter and Probe. The first two are necessary to complete the return of samples collected by MAX-C.
The Titan Saturn System Mission has the highest priority among the deferred missions to the satellites of
the outer planets. Finally, the Neptune System Orbiter and Probe could be an attractive mission for the
next decade if the Uranus Orbiter and Probe cannot be flown in the coming decade for some reason. All
four missions are technically complex, so early technology investments are important for cost and risk
reduction. The technology needs for these missions are discussed in greater detail in Chapter 11.
LAUNCH VEHICLE COSTS
The costs of launch services pose a challenge to NASA’s program of planetary exploration.
Launch costs have risen in recent years for a variety of reasons, and launch costs today tend to be a larger
fraction of total mission costs than they were in the past.
Superimposed on this trend of increasing launch costs are upcoming changes in the fleet of
available launch vehicles. The primary launch vehicles likely to be available to support the missions
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