of these options. The eight projects chosen by the committee are shown in Table A.1. These include three ground-based telescope concepts for NEO detection, two space-based systems for NEO detection, one space-based NEO characterization mission, and two space-based NEO mitigation systems. The results are presented in a range of costs meant to give decision makers some idea of the inherent technological risks and the range of resources that might be required to undertake such projects. However, given the conceptual level of definition of many of these projects, the end points of the range of costs will very likely change significantly as the designs are matured.

A key issue in the cost and schedule assessment was that of ensuring that the cost and schedule estimates were as much as possible on an equal footing with one another despite the limited information available to the cost estimators for some of the projects. All of these cost and schedule estimates for the space- and ground-based activities employed cost and schedule risk analysis to try to achieve this equal footing. SAIC examined the major inputs to the cost model (including mass and power contingencies, heritage assumptions, technology readiness assumptions, etc.), compared these data with past data for similar missions where analogous historical missions existed, and made adjustments so that all missions were estimated on a “level playing field” to the extent feasible. SAIC cost and schedule estimates for each NEO project were also risk-adjusted using a risk rating approach. SAIC assessed technology readiness at the major subsystem level and provided an assessment of the critical technologies on the basis of information provided to the estimators.

The results of the SAIC assessment were reviewed by the committee, and significant differences, both plus and minus, were noted between the numbers produced by the SAIC cost modeling tools and the project team estimates as described in part above.

A second issue facing the committee was to decide how much time and money should be spent having SAIC reconcile the significant differences between the estimates produced by the SAIC assessment and the project team estimates. The committee decided that, based on the dispersions in the level of maturity of the eight projects, it was premature to attempt this reconciliation.

TABLE A.1 Activities and Projects Evaluated by the Study’s Independent Cost Assessment

Activity/Project

Description

Status

Panoramic Survey Telescope and Rapid Response System

(PanSTARRS 4, or PS4)

4 × 1.8 m ground-based optical telescope for NEO detection either at Mauna Kea or Haleakala, Hawaii.

PS1 existing. For NEO, a replicate of planned

PS4 is assumed.

Large Synoptic Survey Telescope

(LSST)

1 × 8.4 m ground-based optical telescope for NEO detection at Cerro Pachon, Chile.

Planned. For NEO, a replicate is assumed.

Binocular Telescope

(Catalina Sky Survey II)

6 × 1.8 m ground-based optical telescope for NEO detection at Mount Hopkins, Arizona.

Planned. For NEO, a replicate is assumed.

0.5-meter Infrared Space Telescope

1 × 0.5 m space-based telescope for NEO detection at L1.

Proposed.

0.5-meter Infrared Space Telescope

(Ball Aerospace and Technologies Corporation NEO Survey)

1 × 0.5 m space-based telescope for NEO detection in a Venus-trailing orbit.

Proposed.

Don Quijote

(European Space Agency, or ESA)

A spacecraft orbiter/observer and an impactor spacecraft for NEO characterization and kinetic impact mitigation.

Proposed (not active in ESA).

Gravity tractor

A spacecraft orbiter that uses the gravitational field between itself and the NEO to mitigate NEO orbit.

Proposed.

Nuclear deflector

A spacecraft orbiter/observer and a nuclear deflector spacecraft for NEO mitigation. The observer spacecraft is assumed to be characterized by the Don Quijote orbiter.

Proposed.



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