Engineering topics
Pete Capizzo
Publications and source records attributed to Pete Capizzo.
A High Inclination Solar Mission Enabled by Near-Term Solar Sail Propulsion
Our current understanding of the Sun, its atmosphere, and the heliosphere is severely limited by a lack of good observations of the Sun’s polar regions. A High Inclination Solar Mission (HISM) mission would go into a 0.48-AU circular solar orbit with at least a 60° inclination to conduct long-term observations of the Sun’s poles using both situ and remote-sensing instruments to study the connections between the Sun, the solar wind, and solar energetic particle events. The propulsion requirements to implement HISM are beyond the capability of conventional chemical propulsion and extremely challenging even for highly efficient solar electric propulsion. To enable HISM and a host of other propulsion-intense space science missions, NASA is actively developing solar sail propulsion, capable of continuous low thrust for the extended periods of time required to meet the delta V requirements of HISM. Upcoming solar sail missions include the Near Earth Asteroid (NEA) Scout (2021 planned launch) and Solar Cruiser (candidate for flight in 2024).Solar sails use sunlight to propel vehicles through space by reflecting solar photons from a large, highly-reflective sail. This continuous photon pressure provides propellantless thrust, allowing for very high delta V maneuvers on long-duration, deep-space exploration. Since the Sun supplies the necessary propulsive energy, solar sails require no onboard propellant, thereby potentially increasing useful payload mass. The NASA MSFC Advanced Concepts Office recently completed a detailed mission concept study of HISM based on the solar sail propulsion technologies being developed for NEA Scout and Solar Cruiser. The HISM spacecraft concept envisions carrying a Doppler & Stokes Imager, a coronagraph, magnetometer, Faraday Cup, a plasma spectrometer, and a radio and plasma wave package to meet the science objectives established for a solar polar orbiting mission in the Heliophysics Decadal Survey. This paper will describe the mission concept and its solar sail propulsion system
Solar Polar Imager Concept
During late 2019 and early 2020, the Advanced Concepts Office design team at NASA’s George C. Marshall Space Flight Center (MSFC) completed a concept study for a Solar Polar Imager (SPI) mission. The goal of the study was to perform a preliminary design of the spacecraft bus containing a minimum set of science instruments and supporting subsystems. The science goal of the SPI mission is to better understand the Sun and the heliosphere by observing the Sun from a high heliographic latitude. A highly inclined orbit (of 75°) allows helioseismology observations from a high latitude, providing measurements in the high latitude regions for the first time. The orbit also allows measurements of the photospheric magnetic fields in the polar regions, as well as direct measurements of the heliospheric magnetic field and solar wind. The high latitude gives the spacecraft a unique top-down view of coronal mass ejections (CMEs) that could affect space weather around Earth and allow the velocity and directions of these CMEs to be better quantified. Solar sail technology is chosen as the propulsion option necessary to deliver the spacecraft to a heliocentric circular orbit at 0.48 AU and an inclination of 75°. The sail area is restricted to 7000 m2, the maximum size that can be developed in the near term. The sail is also assumed to rotate at 1 rpm to avoid buckling of the supporting booms. The total launch mass is 349 kg, which consists of 233 kg for the SPI Bus, 52 kg for the solar sail and deployment mechanisms, and 64 kg for the Spin-up Bus/launch vehicle payload adapter. Dropping the Spin-up Bus after sail deployment, the characteristic acceleration of the sail is about 0.22 mm/s2. The resulting total mission time is just over 13 years, which includes a 3-year duration at the 75° inclination.