Small Satellite Rideshares on Commercial Resupply Missions to the International Space Station SmallSat Conference 2012 Joshua R. Robinson(Presenting) Daniel W. Kwon August 14, 2012 Introduction Gaining access to space is a challenge for small satellites Ride needs to be: Reliable Affordable Compatible with small satellite/payload CRS missions to the ISS have the potential to provide a robust and repetitive platform for rideshare payloads Eight planned missions of the Orbital Antares rocket and Cygnus spacecraft to ISS through 2016 Strong potential for additional missions beyond 2016 2 Cygnus Background COTS = Commercial Orbital Transportation Services Orbital and NASA invested in commercial development of a cargo resupply system under a funded Space Act Agreement Includes first flight of Antares and the first flight of Cygnus to the ISS in 2012 CRS = Commercial Resupply Services IDIQ contract for frequent commercial flights to carry cargo to ISS Includes multiple flights to station through 2016 2011 2012 2013 2014 2015 2016 COTS Demonstration Mission CRS Operational Missions Regular interval fills void left after Shuttle retirement 3 Rideshare Capabilities Rideshare can be a deployable or Ride-Along payloads (Pressurized or unpressurized) Deployable from Antares or Cygnus Altitude: Less than ISS (333-460 km) Inclination: 51.62°-51.68° (±0.1°) Deployment from Cygnus will require adherence to ISS safety regulations Small satellite technology demonstration for Ride-along payloads on Cygnus Non-deployable technology demos can be activated after ISS berthing ISS safety regulations must be evaluated in accordance with the potential hazards (if any) presented by the demo 4 Cygnus Spacecraft Overview ● Pressurized Cargo Module (PCM) Built by Thales Alenia Space Heritage: Multi-Purpose +X Logistics Module Berthing at ISS: Node 2 Common Berthing Mechanism ● Service Module (SM) Built by Orbital Heritage: STAR Bus, Dawn Compatible with Antares Rocket +Y 5 Wallops Launch Pad Turnover Nearing Completion 6 Antares Final Assembly for Hotfire Test on Launch Pad 7 Antares Core Pad Fit Check 8 Cygnus Rideshare Concept of Operations Rendezvous with ISS Depart • Payload Off from ISS • Survival Heater Power Provided Secondary Payload Opportunities post undocking from ISS USN Ground Stations Orbital MCC Controlled Deorbit Payload Ops Center Launch from Wallops 9 Power, Orbit Lifetime, and Data Allocations Power Solar Array Power – 3500 W (32V main bus) Battery Capacity – 20,262 W-Hrs Secondary Payload Power – 1,300 W (OAP) Orbit Altitude: Less than ISS altitude (333-460 km) Inclination: 51.62°-51.68° (±0.1°) Operational lifetime depends on propellant available Up to 1 year possible after standard mission S-Band Communications 3 Mbps downlink 2 kbps uplink Ground network compatibility Universal Space Network NASA Near Earth Network 10 Rideshares on Cygnus Good Fields of View Volume allocation on outer service module Minimal Interference from comm, GPS antennas, and thruster plumes Nominal attitude with –X to sun x Other attitudes feasible Propellant margin dictates slewing capability y z Potential Mounting Location Potential +Z Face Volume Potential -X Face Volume 11 Available External Volume +Z Face 64 cm 27 cm 27 cm 122 cm 61 cm 122 cm 18 cm x 14 cm 31 cm 28 cm Thruster plume clearance 12 Available External Volume -X Face 50 cm 50 cm 24 cm 98 cm 24.1 cm 86 cm 36 cm 50 cm 33 cm 114 cm Thruster plumes 13 Cygnus Mission Control Cygnus Controlled from Orbital Mission Control Center at Dulles (MCC) Dedicated Mission Operation Center Secure Connectivity to NASA and Tracking Networks MCC Controls Cygnus Throughout Mission, Including Secondary Payload Operations After Departure, Cygnus Maneuvers to Customer-Desired Altitude Number of Burns/Duration of Orbit are Dependent on the Amount of Reserve Propellant Remaining 14 Lifetime and Power Lifetime constrained by propellant availability Up to 1 year lifetime for tech demos Excess of power due to large array and redundant systems Sun pointing mode Daily propellant usage for attitude maintenance Sun Pointing Mode Shorter lifetime, but full power capability Gravity gradient mode Longer lifetime through minimal slewing Energy budget may not close for certain sun angles and with tech demos requiring significant power Gravity Gradient Mode 15 Ground Network S-Band Communications Ground network Universal Space Network Data throughput Data throughput to one USN station can average 0.6 GB/day Single Ground Station Latency 83.4% of time latency is less than 200 minutes 16.6% of time latency is > 13 hours Improved latency and throughput through additional USN stations Additional Ground Stations 16 New Missions of Opportunity in LEO National Lab Authorized missions of opportunity In conjunction with NASA, Orbital can provide 1-2 SmallSat Rideshare opportunities per year Starting in 2013 Generally, accommodation Internal to PCM and External to SM Available Mass Dependent on ISS Resupply Needs Cargo Manifest Near Firm at L – 10 Months Decision date for rideshare at L – 18 Months 17 Questions? 18 .