Verification, Validation and Testing The New Worlds ...

Verification, Validation and Testing The New Worlds Observer: First Thoughts a

Jonathan W. Arenberg*a and M.C. Noeckerb Northrop Grumman Space Technology, One Space Park, Redondo Beach, CA. 90278 b Ball Aerospace & Technologies Corp., 1600 Commerce St., Boulder, CO, 80301 ABSTRACT

The New Worlds Observer is mission concept for detection of extra-solar planets made up of two spacecraft, one hosting the starshade and the other the telescope and detectors. These two spacecraft are located ten of thousands of kilometers apart, making full scale terrestrial based testing impossible. Key elements include (a) the starshade, a large scale precision structure; (b) alignment sensors accurate to a meter laterally at 20-80 megameter distances; and (c) high specific impulse thrusters for slew and fine alignment. Clearly, the "test as you fly" approach is simply inapplicable for this mission. However, the telescope requirements are those of a generic space astronomy observatory, alignment sensing has been simplified to solvable problems [Noecker 2007] and navigation is a straightforward application of known principles with flight heritage. From this patchwork, some cohesive testing plan is needed ensure proper performance of the system when deployed on orbit. We will describe our first thoughts on how to verify, validate and test this very large system. We will discuss the roles of subsystem and subscale testing, computer based modeling, model validation and full scale inspection. Keywords: New Worlds Observer, external occulter, starshade, coronagraph, verification, validation, testing

1. INTRODUCTION New Worlds Observer (NWO) is a recently introduced mission designed to fulfill all the requirements of TPF.1,2,3 NWO consists of a telescope and an external starshade aligned with a target star. A sketch of the NWO architecture is shown in Figure 1. Several × 3×1013 km

30,000-80,000 km

Figure 1: Basic architecture of the New Worlds Observer

The starshade has an apodized transmission function designed to cancel out diffraction effects and create a high level of starlight suppression. Cash (2006) began with a hypergaussian apodization function given by 0 ρ