Title: OPAG 1. Outer Planet Missions in Discovery Program: Phase E

Respondent and contact information

Dr. Candice Hansen, on behalf of the Outer Planets Assessment Group (OPAG) Planetary Science Institute [email protected]

Statement of the issue

Phase E costs (spacecraft flight operations costs) result in an inherent cost advantage for missions with a shorter cruise phase, thereby imposing a geographical bias in the Discovery program. There is also a bias against missions that require more time in operation to achieve their science objectives. To better enable the Discovery program to extend its reach and better address NASA’s Science Goals (http://discovery.nasa.gov/p_goals.cfml), Phase E costs should be removed from the cost cap, or a mechanism for Phase E “cost allowances” should be implemented.

Significance to a wide range of proposers

No Discovery Mission has yet ventured beyond the asteroid belt. Addressing this issue is one way to help open the Discovery program to the community that studies the wide variety of planets, moons, and solar system objects beyond the asteroid belt. There may be other mission concepts in the inner Solar System that could also become viable if a longer Phase E was affordable.

Impact of not resolving the issue

Addressing the Phase E cost issue is perhaps the ‘lowest hanging fruit’ for leveling the geographic playing field of the Discovery Program. By not addressing this issue, mission proposers will have to increasingly rely on other cost saving measures (e.g. new technologies, less capable subsystems, etc.), almost all of which come with increased risk to the mission. Based on current plans NASA will not have a single active mission beyond Mars after 2017, a dramatic retreat from the past when NASA was the clear leader in exploration.

Suggested pathway(s) to resolve the issue

Here we provide three potential pathways for resolving this issue. This list is by no means complete. - Option 1 is to incorporate some function such as “The cost cap is increased by {a few} $M per year of phase E required beyond 2 years.” The incentive should be sufficiently small to prevent “gaming” of proposals to exploit this rule. - Option 2 is to invest in, and enable, cruise phase hibernation and other mechanisms for reducing overall Phase E cost. Such capability has been demonstrated, but it is still considered risky, which may downgrade some proposals. - Option 3 is to partner with the Astrophysics Division to explore options for cruise phase science wherein Phase E cost could be offset by a partnership with Astrophysics.

Potential impacts of the suggested solution(s)

The potential impact from each of the above-described solutions includes, but is not limited to, the following: - Option 1: Potentially the simplest and most effective solution for opening the Discovery program to outer solar system targets and other long-duration missions. This option would likely lead to new mission designs that better optimize science return. Pressure on New Frontiers and Flagship missions could, in part, be alleviated by providing this mechanism for addressing outer solar system science. - Option 2: Investment in Phase E cost reduction mechanisms would likely yield positive repercussions through all mission classes, leading to reduction in Discovery, New Frontiers, and Flagship mission Phase E costs. - Option 3: Partnering with the Astrophysics directorate for Phase E operation could yield new science results during a phase of the mission that is not normally of great interest to the Planetary Science community. The astrophysics community has expressed considerable interest in utilizing the cruise phase of missions that go beyond the asteroid belt in order to, for instance, better characterize the dust and scattering of light in the ecliptic.