Breakthrough capability for UVOIR space astronomy: Reaching the darkest sky

Matthew A Greenhouse,Scott W Benson,Jacob Englander,Robert D Falck,Dale J Fixsen,Jonathan P Gardner,Jeffrey W Kruk,Steven R Oleson,Harley A Thronson

doi:10.1016/j.asr.2014.11.007

Abstract

We describe how availability of new solar electric propulsion (SEP) technology can substantially increase the science capability of space astronomy missions working within the near-UV to far-infrared (UVOIR) spectrum by making dark sky orbits accessible for the first time. We present a proof of concept case study in which SEP is used to enable a 700kg Explorer-class observatory payload to reach an orbit beyond where the zodiacal dust limits observatory sensitivity. The resulting scientific performance advantage relative to a Sun–Earth L2 point orbit is presented and discussed. We find that making SEP available to astrophysics Explorers can enable this small payload program to rival the science performance of much larger long development-time systems. We also present flight dynamics analysis which illustrates that this concept can be extended beyond Explorers to substantially improve the sensitivity performance of heavier (7000kg) flagship-class astrophysics payloads such as the UVOIR successor to the James Webb Space Telescope by using high power SEP that is being developed for the Asteroid Redirect Robotics Mission.

Highlights

The Earth is imbedded in a cloud of dust grains that are produced by comet outgassing and impact fragmentation of asteroids that surround the inner planets
This interplanetary dust (IPD) cloud produces a UVOIR background light, known as the zodiacal light, through which all space observatories have had to observe. This background light is a source of noise that typically limits the sensitivity of all space astronomy imaging systems that have operated within the nearUV to far-infrared spectrum
In Appendix A, we look beyond Explorer-class mission application and present flight dynamics analysis which illustrates the potential of high power electric propulsion systems being developed for deep space human exploration to enable a 7000 kg flagship-class astrophysics mission to reach dark sky

Summary

Introduction

The Earth is imbedded in a cloud of dust grains that are produced by comet outgassing and impact fragmentation of asteroids that surround the inner planets. This interplanetary dust (IPD) cloud produces a UVOIR background light, known as the zodiacal light, through which all space observatories have had to observe. The EZE refers to a detailed mission architecture study (Benson et al, 2011; Greenhouse et al, 2012) that was conducted jointly by the Goddard Space Flight Center and the Glenn Research Center (GRC) using the GRC COllaborative Modeling for Parametric Assessment of Space Systems (COMPASS) facility to determine if and how a technically mature SEP system, such as the NASA Evolutionary Xeon Thruster () shown, can be used to enable astrophysics Explorer missions to operate in an IPD density environment that is very low relative to the SEL2 point in order to increase the scientific potency of this small payload program. We found that acceptable science data downlink rates in the range of approximately 0.5–3.5 Mbps can be enabled by conventional Ka-band (32 GHz) flight-ready

AU 30 deg elliptical

Findings

Discussion

Summary and conclusions