We discuss two geosynchronous gravitational wave mission concepts, which we generically name gLISA. One relies on the science instrument hosting program onboard geostationary commercial satellites, while the other takes advantage of recent developments in the aerospace industry that result in dramatic satellite and launching vehicle cost reductions for a dedicated geosynchronous mission. To achieve the required level of disturbance free-fall onboard these large and heavy platforms we propose a "two-stage" drag-free system, which incorporates the Modular Gravitational Reference Sensor (MGRS) (developed at Stanford University) and does not rely on the use of micro-Newton thrusters. Although both mission concepts are characterized by different technical and programmatic challenges, individually they could be flown and operated at a cost significantly lower than those of previously envisioned gravitational wave missions. We estimate both mission concepts to cost less than 500M US$ each, and in the year 2015 we will perform at JPL a detailed selecting mission cost analysis.

翻译：我们讨论了两个地球同步重力波飞行任务概念,我们将其统称为GLISA。一个依靠在地球静止商业卫星上的科学仪器托管方案,另一个利用航空航天工业最近的发展情况,导致卫星和运载火箭专门地球同步飞行任务的成本大幅下降。为了在这些大型和重型平台上达到所需的扰动自由降落水平,我们提议了一个“两阶段”的拖动系统,它包含模块引力参考传感器(MGRS)(斯坦福大学开发),并不依赖微型牛顿推进器的使用。虽然这两个飞行任务概念都具有不同的技术和方案挑战的特点,但个别飞行和运行的成本可以大大低于先前设想的引力波飞行任务的成本。我们估计,这两个飞行任务概念的成本都低于每个50万美元,到2015年,我们将在日本大学实验室进行详细的飞行任务成本选择分析。