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The Green Propellant Infusion Mission (GPIM) spacecraft was launched in June of 2019 as a secondary payload on the Air Force’s STP-2 Falcon Heavy launch vehicle. GPIM is a BCP-100, a line of ESPA class spacecraft designed by Ball. The BCP-100 was designed around the capability to support multiple payloads on a single platform, and be able to fly in a wide range of orbits without the need to reconfigure the spacecraft in any way. Proving the flexibility and multi-role capability of the BCP-100 design, there are three secondary payloads on GPIM. In addition to the green propellant payload, iMESA, SWATS, and SOS are hosted on the spacecraft. These were provided by the Air Force through their Space Experiments Review Board (SERB) payload list. Finally, an advanced multi-layer insulation (MLI) technology, integrated MLI (IMLI), was employed as insulation for the propulsion subsystem. This technology was developed by Ball and Quest Thermal Group under Small Business Innovative Research (SBIR) funding provided by NASA STMD. GPIM adds to the 15 years of combined flight time for the BCP-100 line. Ball Aerospace built the GPIM spacecraft for NASA’s Space Technology Mission Directorate (STMD) in order to provide a platform to accomplish on-orbit testing and validation of an AF-M315E based green propellant propulsion subsystem. After a very successful spacecraft commissioning phase that was completed in less than 24 hours, check out of the primary green propellant payload commenced. This included testing the primary and redundant catbed heaters, opening the latch valve, and commanding the thrusters in both open loop and closed loop control modes, all of which was accomplished within three and a half days of being on-orbit. The propulsion system employs five protoflight 1 N thrusters, four for attitude control and the fifth for use during delta-v burns to provide higher thrust. Characterization of the green propellant system has been on-going. This characterization includes performing closed loop delta-v burns, 3-axis thruster-based attitude control, and momentum dumping. In addition to these tests, on-orbit measurement of the thruster impulse-bit has been performed over the course of the mission. This measurement involves a complex command sequence in which the spacecraft must execute a delta-v, perform multiple maneuvers, spin down the reaction wheels, and execute a series of 200 msec long open loop thruster pulses. Analysis of the spacecraft motion that results from each thruster pulse provides the amount of force that was applied. This paper provides a brief background of the GPIM program, including objectives of the technology demonstration, and presents on-orbit flight results of propulsion tests performed to date.

The Green Propellant Infusion Mission (GPIM) Project is sponsored by the NASA Space Technology Mission Directorate (STMD) as part of the work conducted by the Technology Demonstration Mission (TDM) Office. The goal of GPIM is to advance the technology readiness level (TRL) of a green propulsion technology based on the monopropellant AF-M315E via flight demonstration. As the Project lead, Ball Aerospace & Technologies Corp. (Ball Aerospace) is coordinating contributions from industry, NASA, and the U.S. Air Force to execute the GPIM project. In May 2014, the GPIM Project was authorized to integrate three Air Force Science Experiments Review Board (SERB) secondary payloads onto the GPIM space vehicle: iMESA-R, SWATS and SOS. This paper summarizes the flexibility of the BCP-100 spacecraft and describes the work to accommodate the three Air Force SERB payloads. The GPIM space vehicle consists of a GPPS Module mounted on a BCP-100 bus module with the three SERB payloads mounted to a bus side panel.

The Green Propellant Infusion Mission (GPIM) Project is sponsored by the NASA Space Technology Mission Directorate (STMD) as part of the work conducted by the Technology Demonstration Mission (TDM) Office. The goal of GPIM is to advance the technology readiness level (TRL) of a green propulsion technology based on the monopropellant AF-M315E via flight demonstration. Ball Aerospace & Technolo-gies Corp. (Ball Aerospace) is leading an Industry, NASA and Department of Defense (DoD) team to execute the GPIM Project. The green propellant propulsion subsystem (GPPS) is being developed and manufactured by Aerojet Rocketdyne. Ball Aerospace is providing the spacecraft bus, a Ball Configu-rable Platform (BCP)-100, to which the GPPS payload is integrated. Ball is providing all spacecraft level assembly, integration and test (AI&T) activities and manages launch services and flight operations. The Air Force Space & Missile Systems Center (SMC) will launch GPIM as a secondary payload via the STP-2 Mission. The GPIM space vehicle will be operated through SMC's Multi-Mission Satellite Operations Center (MMSOC). This paper describes the BCP-100 space-craft and its straight-forward modification to accommodate and operate the GPPS, the GPIM launch vehicle interface and ground system.

We can now accurately theoretically predict the embedded element gain and 2-way scan loss of the PAVE PAWS array to within 0.25 dB over 420–450 MHz band up to 60° scan and 0.4 dB up to 75° scan. When the PAVE PAWS array, which uses a bent, crossed-dipole element, was built in the 1970's tools were not available for accurate prediction. Expensive experimental trial-and-error measurements were used. The theoretical predictions were made using the Ansoft High Frequency Structure Simulator (HFSS). Accurate mutual coupling measurements made in 1977 on a 320 element PAVE PAWS test array were used for verification.

The tombs in the Valley of the Kings can be protected from damage by flash floods by planning for emergencies, monitoring and maintaining tomb conditions, and implementing flood-protection measures.

SPIE grants to authors (and their employers) of papers, posters, and presentation recordings published in SPIE Proceedings or SPIE Journals on the SPIE Digital Library (hereinafter "publications") the right to post an author-prepared version or an official version (preferred version) of the publication on an internal or external server controlled exclusively by the author/employer or the entity funding the research, provided that (a) such posting is noncommercial in nature and the publication is made available to users without charge; (b) an appropriate copyright notice and citation appear with the publication; and (c) a link to SPIE's official online version of the publication is provided using the item's DOI. This authorization does not extend to third-party web sites not owned and maintained by the author/employer such as ResearchGate, Academia.edu, YouTube, etc. The Imaging X-ray Polarimetry Explorer (IXPE) will add polarization to the properties (time, energy, and position) observed in x-ray astronomy. A NASA Astrophysics Small Explorer (SMEX) in partnership with the Italian Space Agency (ASI), IXPE will measure the 2-8-keV polarization of a few dozen sources during the first 2 years following its 2021 launch. The IXPE Observatory includes three identical x-ray telescopes, each comprising a 4-m-focal-length (grazingincidence) mirror module assembly (MMA) and a polarization-sensitive (imaging) detector unit (DU), separated by a deployable optical bench. The Observatory's Spacecraft provides typical subsystems (mechanical, structural, thermal, power, electrical, telecommunications, etc.), an attitude determination and control subsystem for 3-axis stabilized pointing, and a command and data handling subsystem communicating with the science instrument and the Spacecraft subsystems.