Proceedings of the 2013 International Workshop on Planning & Scheduling for Space, Mountain View, CA, USA, March 25-26, 2013, Paper AIAA-2013-XXXX. THIS SPACE MUST BE KEPT BLANK] Multi-Mission Scheduling Operations at UC Berkeley Manfred Bester, Gregory Picard, Bryce Roberts, Mark Lewis, and Sabine Frey Space Sciences Laboratory, University of California, Berkeley [email protected], [email protected], [email protected], [email protected], [email protected] Abstract completed in 2011 when both probes were inserted into The University of California, Berkeley conducts mission stable lunar orbits (Cosgrove et al. 2012, Bester et al. operations for eight spacecraft at present. Communications 2013). with the orbiting spacecraft are established via a multitude of network resources, including all NASA networks, plus • The Nuclear Spectroscopic Telescope Array (NuSTAR) – assets provided by foreign space agencies and commercial a NASA SMEX mission launched in June 2012 – is a companies. Mission planning is based on the science re- high-energy X-ray observatory carrying twin telescopes quirements as well as accessibility to communications net- with focusing optics (Kim et al. 2013). work resources. The integrated scheduling process is com- plex and is supported by partly automated software tools. • The CubeSat for Ion, Neutral, Electron, and MAgnetic Challenges encountered and lessons learned are described. fields (CINEMA) – the first CubeSat built in-house at SSL – launched in September 2012. The project home page can be found at http://sprg.ssl.berkeley.edu/cinema. Introduction A summary of these missions and their characteristics is The University of California, Berkeley (UCB) currently provided in Table A1 in the Appendix. In addition to those conducts operations for eight spacecraft from its Multi- five missions, the UCB MOC also operated the Fast Auro- mission Operations Center (MOC) at Space Sciences ral SnapshoT Explorer (FAST) – a NASA SMEX mission Laboratory (SSL). Science goals and observations fall into launched in August 1996 – and the Cosmic Hot Interstellar the solar/heliophysics and astronomy categories: Plasma Spectrometer (CHIPS) – a NASA University-class • The Reuven Ramaty High-Energy Solar Spectroscopic Explorer (UNEX), launched in January 2003. After many Imager (RHESSI) – a NASA Small Explorer (SMEX), years of successful operations, these two missions came to launched in February 2002 – is a solar observatory (Lin, a termination in 2009 and 2008, respectively. Dennis, and Benz 2002). Mission requirements for the currently operating mis- sions are levied onto planning and scheduling, and are ex- Time History of Events and Macroscale Interactions • plained in more detail further below. Mission orbits in- during Substorms (THEMIS) – a NASA Medium Ex- clude the low-Earth orbit (LEO), as well as highly elliptical plorer (MIDEX), launched in February 2007 – is a mag- orbit (HEO) regimes around the Earth and the Moon, and netospheric constellation of originally five spacecraft, with a wide range of inclinations. Scheduling tasks are called probes (Angelopoulos 2008). Three of these rather complex, as they involve arranging for communica- probes (P3, P4, P5) are currently still operating in Earth tions opportunities via a large number of ground stations orbit while the other two probes (P1, P2) have been across multiple, dissimilar networks to allow for spacecraft transferred into lunar orbits. command and control, as well as science data return. • Acceleration, Reconnection, Turbulence and Electrody- Mission planning is interrelated with scheduling to en- namics of the Moon’s Interaction with the Sun sure science data are acquired onboard and returned to the (ARTEMIS) – two of the original five THEMIS probes – ground. In addition, special operations events such as is a new mission that started after THEMIS completed thrust maneuvers need to be covered. THEMIS and its primary two-year mission phase (Angelopoulos ARTEMIS also require tracking passes to be scheduled to 2013). The low-energy lunar transfer trajectory was collect radiometric tracking data for accurate orbit deter- mination in both Earth and lunar environments. Copyright © 2013. All rights reserved. Communications Networks Mission planning for RHESSI is relatively straightfor- ward, as the observatory is pointed at the Sun most of the Currently the following communications networks are in time. RHESSI is pointed off the Sun once or twice per year operational use at the Berkeley MOC to support RHESSI, for seasonal observations of astronomical targets passing THEMIS, ARTEMIS, NuSTAR and CINEMA: near the Sun. 1. NASA Near Earth Network (NEN) ground stations at However, collected on-board data volumes are depend- Wallops Island, VA, White Sands, NM and Santiago, ent on solar activity and are therefore difficult to predict. Chile (WLP 11M, LEOT; WHS 18M1; AGO 9M, 13M) On-board data decimation and generation of ancillary in- strument data can be adjusted to accommodate times when 2. NASA Space Network (SN) ground stations at White the Sun is active. During times of high solar activity the Sands, NM and Guam plus five operational Tracking operations team arranges for additional downlink band- and Data Relay Satellites (TDRS 5, 6, 7, 9, 10) width by scheduling passes at the Weilheim, Germany 3. NASA Deep Space Network (DSN) ground stations at ground station. three complexes at Goldstone, CA; Madrid, Spain; and Canberra, Australia (DSS-14, 15, 24, 27, 34, 43, 45, 54, NuSTAR 63, 65) The NuSTAR observatory is a three-axis stabilized instru- 4. German Aerospace Center (DLR) ground station at ment platform carrying two co-aligned hard X-ray tele- Weilheim, Germany (WHM 9M, 15M1, 15M2) scopes with grazing-incidence, nested mirrors with a 10-m 5. Italian Space Agency (ASI) ground station at Malindi, focal length (Kim et al. 2013). Kenya (MLD 10M1, 10M2) The concept of operations includes long, pointed obser- 6. Universal Space Network (USN) ground stations at vations of survey fields or of specific science targets, such South Point, Hawaii and Dongara, Australia (USNHI as supermassive black holes. In addition, the operations 13M1, 13M2; USNAU 13M1) team may be alerted by the Principal Investigator to sup- 7. Kongsberg Satellite Services (KSAT) ground station at port observations of targets of opportunity on short notice. Singapore, Singapore (SNG 9M1) Planning of observations for NuSTAR is carried out at the Science Operations Center (SOC) at the California In- 8. University of California, Berkeley (UCB) ground sta- stitute of Technology (Caltech), Pasadena. The SOC deliv- tion at Berkeley, California (BGS 11M) ers to the MOC observatory pointing requests via an elec- The architecture of the ground data system at the MOC tronic messaging interface. The information includes time- integrates all of these networks elements. Transmission tagged target slew coordinates, as well as expected photon Control Protocol/Internet Protocol (TCP/IP) based socket count rates and a criticality/priority classification code. interfaces are utilized across secure mission networks to The MOC in turn processes the observatory pointing re- establish connectivity for real-time spacecraft command quests, and assesses how many ground station passes are and control functions. The MOC is responsible for delivery required to recover the expected science data volume. Fur- of acquisition data to all supporting networks to allow for ther details of the mission planning and mission operations communications antenna configuration and pointing. processes will be described elsewhere. The level of work required for planning observations and science data acquisition varies greatly between the five CINEMA supported missions. The CINEMA CubeSat carries a three-axis magnetometer mounted on a boom, and a solid-state detector to measure Mission Planning for Single Spacecraft auroral ion and electron precipitations. Due to limited on- board power resources, passes can be afforded only a few This section covers the mission planning activities for the times per day. Passes are scheduled only at the Berkeley single spacecraft missions operated at UCB, namely Ground Station, using a S-band downlink and a UHF RHESSI, NuSTAR, and CINEMA. uplink. At present CINEMA is still in an experimental phase to RHESSI improve the concept of operations. The RHESSI observatory carries only one instrument, a spectroscopic imager to measure solar flares at hard X-ray Mission Planning for Constellations and gamma-ray wavelengths. The instrument consists of a rotating grid collimator and cooled germanium detectors to Mission planning for the THEMIS constellation, and since achieve high spatial as well as high spectral resolution. 2009 for THEMIS and ARTEMIS, includes activities to determine, based on inputs from the science team, where and when along the orbits science instruments are config- Regions of interest were originally implemented for the ured and science data are acquired, and how science data THEMIS multiprobe mission to define time intervals, such are transmitted to the ground to achieve mission goals. as crossing times of specific regions in space that sequenc- Activities related to mission trajectory design, execution ing of on-board activities can be queued of off. In total, of thrust maneuvers, and navigation operations that have THEMIS and ARTEMIS use 26 ROIs for mission planning an influence on mission planning as well, are described purposes. Some of these regions are defined to indicate