Enabling and Enhancing Astrophysical Observations with Autonomous Systems Rashied Amini1;a, Steve Chien1, Lorraine Fesq1, Jeremy Frank2 , Ksenia Kolcio3, Bertrand Mennsesson1, Sara Seager4, Rachel Street5 July 10, 2019 Endorsements Patricia Beauchamp1, John Day1, Russell Genet6, Jason Glenn7, Ryan Mackey1, Marco Quadrelli1, Rebecca Ringuette8, Daniel Stern1, Tiago Vaquero1 1NASA Jet Propulsion Laboratory 2NASA Ames Research Center 3Okean Solutions 4 arXiv:2009.07361v1 [astro-ph.IM] 15 Sep 2020 Massachusetts Institute of Technology 5Las Cumbres Observatory 6California Polytechnic State University 7University of Colorado at Boulder 8University of Iowa a [email protected] c 2019 California Institute of Technology. Government sponsorship acknowledged. 1 Executive Summary Servicing is a legal requirement for WFIRST Autonomy is the ability of a system to achieve and the Flagship mission of the 2030s [5], yet goals while operating independently of exter- past and planned demonstrations may not pro- nal control [1]. The revolutionary advantages vide sufficient future heritage to confidently meet of autonomous systems are recognized in nu- this requirement. In-space assembly (ISA) is cur- merous markets, e.g. automotive, aeronautics. rently being evaluated to construct large aper- Acknowledging the revolutionary impact of au- ture space telescopes [6]. For both servicing and tonomous systems, demand is increasing from ISA, there are questions about how nominal op- consumers and businesses alike and investments erations will be assured, the feasibility of teleop- have grown year-over-year to meet demand. In eration in deep space, and response to anomalies self-driving cars alone, $76B has been invested during robotic operation. from 2014 to 2017 [2]. In the previous Planetary The past decade has seen a revolution in Science Decadal, increased autonomy was identi- the access to space, with low cost launch ve- fied as one of eight core multi-mission technolo- hicles, commercial off-the-shelf technology, and gies required for future missions [3]. programs that have enabled numerous cubesat The impact of autonomous systems on our missions. NASA and academic institutions will ability to observe the universe can be just as be operating more small satellites and opera- revolutionary [4]. However, relevant autonomy tions centers will need to adapt. The need will work to date has been limited in scope and too be greater if future human exploration goals to disjoint to confidently deliver anticipated capa- launch dozens of cubesats per SLS launch is bilities, like in-space assembly (ISA), in a low met [7]. Operating autonomous observatories risk and repeatable manner in the 2020s or even provides one solution to this impending prob- the 2030s. This paper includes the following so lem. Notably, several ground-based observato- that the astrophysics community can realize the ries, like Las Cumbres and ALMA observato- benefits of autonomous systems: ries, have begun using autonomous operations to command large arrays of telescopes, identi- • A description of autonomous systems with fying advantages for observatories that follow relevant examples their example. Planet and presumably SpaceX's • Enabled and enhanced observations with Starlink, private space mission operators, have autonomous systems reached a break point where traditional com- manding is inadequate to command their large • Gaps in adopting autonomous systems constellations and are operating spacecraft with automated scheduling [8]. • Suggested recommendations for adoption by Gehrels/Swift is an inspiring example of the the Astro2020 Decadal time-domain observations that autonomous sys- As we consider the observations necessary tems enable. The multi-messenger approach for to answer new science questions formed in the characterizing the physics leading to and result- 2010s, the need for autonomy is clear. Concept ing from gravity wave events will require sim- studies for the Astro2020 Decadal require opera- ilar missions to Gehrels/Swift. Gehrels/Swift tions that are more complex than ever before. relies on prescriptive state machines, statically- Increasingly complex space- and ground-based programmed conditions and routines also used observatories have more systems, components, in spacecraft fault protection, to execute au- and software. More engineering complexity in- tonomous Gamma-ray burst (GRB) follow-up variably means that there are more paths for observations. The system autonomy approach anomalies to disrupt a system's ability to per- detailed in this paper offers several advan- form its mission. This can reduce observational tages over state machines in terms of dynamic efficiency and potentially negate the advantages decision-making and scalability. One major ad- of larger apertures and more sensitive detectors. vantage is the ability to make decisions using on- 1 missions, for instance through a cost cap credit. Adoption in the 2020s will reduce the risk of fu- ture Flagship servicing missions. 2 Understanding Autonomous Systems Observing the proceedings of the Space Astro- physics Landscape in 2020 and Beyond meeting, it is clear that a gap exists between the expec- tations of the astrophysics community and the technical readiness of autonomy technologies re- quired to meet these expectations. To under- Figure 1: Effective, reliable autonomous systems stand this gap, we need to first define autonomy must coordinate between the resources utilized by a in a relevant context. system's lower level functions to achieve system-level goals. AppendixA offers an illustrated example of a A hierarchy of systems is represented in Fig- system autonomy framework. ure1. At the bottom of the hierarchy is the functional-level, where control and autonomy is board analysis of data to change an observation exercised in a limited domain. Functional control program. is the commanding actuators and sensors, e.g. a Dynamic decision-making also enables the command is sent and a motor turns at a com- restoration of functionality in the event of an manded rate. Functional autonomy is decision- anomaly. This type of decision-making is en- making within the boundaries of the functional abled by on-board health monitoring software, element. A simple example is a state machine which monitors and diagnoses hardware anoma- that (dis)engages a heater based on thermome- lies to support autonomous systems. This re- ter input. A more complicated example is an sults in greater observational efficiency and uni- attitude controller that takes inputs of attitude versally benefits all observatories. For observa- knowledge (e.g. star trackers). Its output is con- tories with competed time, this means more PIs trol system actuation to maintain a desired atti- can be supported. For mapping missions, like tude. Pre-programmed routines filter inputs and the Galaxy Evolution Probe, Probe of Inflation evaluate conflicting knowledge, resulting in pre- and Cosmic Origins, and Cosmic Dawn Intensity dictable behavior. Mapper Probe, greater depths can be reached More complex forms of functional auton- per unit time [9, 10, 11]. For time-domain sur- omy have already been demonstrated and are veys, this results in less gaps in data. currently being developed. For instance, au- As evidenced by private investments and de- tonomous optical navigation determines devia- velopments in ground-based observatories, the tion from desired orbit ephemeris and has been adoption of autonomous systems in space is in- used on Deep Space-1, Deep Impact/EPOXI, evitable. There are two questions to the field: other planetary missions, and soon Arcsecond \When will we start using it?" and \How will Space Telescope Enabling Research in Astro- we start using it?" Given the ambitions of physics (ASTERIA) [12, 13]. On-going work the community, the time to begin is now. In on servicing and ISA utilizes computer vision as order to use it in a repeatable, low risk, and a knowledge source to control robotic actuation cost-effective way, NASA, spacecraft vendors, [6]. On-orbit robotic servicing was first demon- and the astrophysics community need to coop- strated on DARPA's OrbitalExpress in 2007 [14]. eratively develop a coherent technical path for- In the next few years, RESTORE-L will be used ward. To do so, our primary recommenda- to service Landsat-7 in low earth orbit using tele- tion is for NASA to incentivize the use of operation after autonomous docking [15]. autonomous systems for competed space However, functional elements utilize system 2 resources, e.g. time, power, attitude, data stor- age, etc. Spacecraft are resource limited and efficient use is critical to mission success. Dif- ferent activities may utilize resources in a mu- tually exclusive way; for instance, a space tele- scope may not be able to point its telescope at a target while simultaneously pointing its antenna toward Earth for communications. Some re- sources are zero-sum but accommodating of mul- tiple spacecraft goals; for instance, all powered equipment require power but not all subsystem power modes can be supported simultaneously. Thus, there is a state of competition between different system goals. In the current state of practice, this competition is resolved by human planning during operations. Tools are used to define system activities, like observing and trans- mitting data, based on commands that are tied Figure 2: Task networks offer numerous pathways in to certain resources. The goals of the scientists time and state-space to achieve goals requested from to observe the sky and