Space Launch System keeps pace
By Brian O'Connor|December 2016
The Space Environmental Systems Program Committee focuses on environmental and thermal control technologies for aircraft, spacecraft and space missions.
NASA’s Space Launch System, or SLS, continued development toward a November 2018 launch date of the Block 1 (70-metric ton lift) vehicle, and has begun development of the Block 1B (105-metric ton lift). In June, the Qualification Motor 2 test firing was completed at Orbital ATK’s Promontory Propulsion Systems facility in northern Utah. The motor was a full-scale five-segment Solid Rocket Booster that will be used for SLS. By cooling the motor for more than a month using large air-conditioning units, this test was conducted at the minimum propellant temperature of 40 degrees Fahrenheit. When ignited, those temperatures inside the booster reach nearly 6,000 degrees Fahrenheit.
The Marshall Space Flight Center in Huntsville, Alabama, continued development of more environmentally friendly cryogenic insulation materials for use on the Block 1 Core Stage and Block 1B Upper Stage cryogenic tanks. Testing of the foam systems will be conducted by NASA and prime contractor Boeing to qualify the insulation for the challenging environments SLS will experience before and during flight. Marshall has tested conceptual designs to protect the Core Stage flight base heat shield thermal protection system during the “Green Run” static test firing. The designs involved spray-on foam insulations that could be removed after testing, as well as surface coatings to reduce the plume radiation heat loading on the heat shield. Additionally, several characterization development tests of various cryogenic areas of the vehicle that could form ice and frost have been performed. Ice and frost could lead to both additional vehicle mass and a potential debris source that could lead to dangerous impact damage during ascent.
GOES-R, the first of four, planned next-generation Geostationary Operational Environmental Satellites, completed environmental testing at Lockheed Martin Space Systems in Denver earlier this year and was flown to Florida aboard a massive U.S. Air Force C-5M Super Galaxy cargo plane. There, it arrived at the Astrotech Space Operations facility in Titusville outside Kennedy Space Center for final assembly, including thermal blanket installation, electrical testing and fueling. GOES-R will provide faster weather coverage, better data for severe weather forecasts, advanced warning of space weather hazards, and improved transportation safety. The mission operations team conducted the final mission rehearsal in September from the NOAA Satellite Operations Facility in Suitland, Maryland. The satellite was scheduled to launch aboard an Atlas V 541 at Cape Canaveral in late November to begin its 15-year mission.
The thermal design for the Iodine Satellite has progressed leading up to critical design review. The 12-unit cubesat system has unique thermal considerations with an iodine propellant that requires specific temperature profiles throughout the feed system to sublimate the propellant at specific flow rates, while mitigating deposition along the flow path. The spacecraft thermal design is compartmentalized and will demonstrate a power density an order of magnitude higher than state-of-the-art smallsats. The thermal design utilizes both custom heaters and insulation; it also may rely on attitude control during operation to maintain appropriate temperatures. NASA’s Glenn Research Center in Cleveland is leading the propulsion thermal design and Marshall is leading the integrated bus solution. ★