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Ken Kobayashi

Publications and source records attributed to Ken Kobayashi.

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

The High Inclination Solar Mission (HISM)

The High Inclination Solar Mission (HISM) is a concept for an out-of-the-ecliptic mission for observing the Sun and the heliosphere. The mission profile is largely based on the Solar Polar Imager concept; initially taking ~2.6 yrs to spiral in to a 0.48 AU equatorial orbit, then increasing the orbital inclination at a rate of 10 degrees per year, ultimately reaching an inclination of >75 degrees at the end of the mission. The orbital profile is achieved using solar sails derived from the technology currently being developed for the Solar Cruiser mission. HISM remote sensing instruments comprise an imaging spectropolarimeter (Doppler imager/magnetograph) and a visible light coronagraph. The in-situ instruments include a Faraday cup, an ion composition spectrometer, and magnetometers. Plasma wave measurements are made with electrical antennas and high speed magnetometers. The 7,000 m2 sail used in mission assessment is a direct extension of the 4-quadrant, 1,600 m2 Solar Cruiser Phase-A design and employs the same type of high strength composite boom, deployment mechanism, and membrane technology. The sail system modeled is spun (~1 rpm) to assure required boom characteristics with margin. The spacecraft bus features a fine-pointing 3-axis stabilized instrument platform that allows full science observations as soon as the spacecraft reaches the 0.48 AU orbit.

Solar sail, high inclination, solar physics, helio↗
NASA NTRSDate not supplied

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 Sail↗
NASA NTRSDate not supplied

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.

Dan Thomas↗
NASA NTRSDate not supplied

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.

Dan Thomas↗
NASA NTRSDate not supplied

Wavelength Calibration of the Full-sun Ultraviolet Rocket SpecTrograph (FURST)

The Sun has a well-known periodicity in sunspot number and magnetic field variation. The underlying cause of this 11-year cycle is not fully understood and has yet to be connected with those processes in other stellar objects. The Full-sun Ultraviolet Rocket SpecTrograph (FURST) is a sounding rocket payload being developed by Montana State University (MSU) alongside the Marshall Space Flight Center(MSFC) solar physics group. Scheduled to launch from White Sands Missile Range (WSMR) in 2022, this instrument is unique in that it will provide the connection between stellar observatories with measurements of our Sun. It will achieve this through measuring high-resolution full-disk spectral irradiance. We aim to obtain a wavelength resolution R>10,000 in the 120 - 181 nm UltraViolet (UV) range, on par with that of the Hubble (HST) Space Telescope Imaging Spectrograph (STIS). This resolution goal will allow us to study the relatively low-temperature plasma in the chromosphere and lower corona with spectral accuracy down to 0.1 Å (a Doppler-shift of about±30 km/s). In addition, the Lyman Alpha(121 nm) line is known to saturate most CCD electronics. These factors illustrate the particular challenge of precise wavelength calibration for this spectral range. We are building a collimator in order to calibrate the FURST instrument under these strict spectral requirements. This paper will present the results of our simulation of the diagnostic lamp signal to be used for wavelength calibration. The simulation allows us to begin to account for photon noise, electronic readout noise, and statistical error. These in turn lead to the development of our pre- and post-launch calibration plans. Future work includes absolute radiometric and wavelength calibration with this new collimator. In addition, the ability of FURST to measure small Doppler-shifts will provide capabilities for planetary atmospheric scientists. This impact is coupled with the diverse international partnership created by the closely-knit Sounding Rocket teams around the globe. Sounding Rockets like FURST have an even broader impact, as they encourage future satellite missions under the prospect of long-term observations

FURST↗
NASA NTRSDate not supplied

Wavelength Calibration of the Full-sun Ultraviolet Rocket SpecTrograph: (FURST)

The Sun has a well-known periodicity in sunspot number and magnetic field variation. The underlying cause of this 11-year cycle is not fully understood and has yet to be connected with those processes in other stellar objects. The Full-sun Ultraviolet Rocket SpecTrograph (FURST) is a sounding rocket payload being developed by Montana State University (MSU) alongside the Marshall Space Flight Center (MSFC) solar physics group. Scheduled to launch from White Sands Missile Range (WSMR) in 2022, this instrument is unique in that it will provide the connection between stellar observatories with measurements of our Sun. It will achieve this through extremely high-resolution full-disk spectroscopy in EUV. We aim to obtain a wavelength resolution R > 10,000 in the 115 - 181 nm range, on par with that of the Hubble (HST) Space Telescope Imaging Spectrograph (STIS). The Lyman Alpha line (121 nm) is known to oversaturate most CCD electronics and is of particular challenge for this spectral range. In addition, this resolution goal will allow us to study the 3 km/s motion (a Doppler-shift of about 0.01 Angstroms) of the relatively low-temperature plasma in the chromosphere and lower corona. This paper will present the results of our simulation of the diagnostic lamp signal to be used in this wavelength calibration. To test the viability of this precise of a device, we are building a collimator capable of calibrating the FURST instrument under these strict radiometric requirements. By way of a diagnostic lamp simulation, we will account for photon noise, CCD electronic readout noise, and statistical error. These will lead to the development of our pre- and post-launch calibration plan. Future work includes absolute radiometric and wavelength calibration with this new collimator. In addition, the ability of FURST to measure extremely small Doppler-shifts will provide capabilities for planetary atmospheric scientists. This impact is coupled with the diverse international partnership created by the closely-knit Sounding Rocket teams across the globe. These Sounding Rockets have an even broader impact, as they encourage future satellite missions under the prospect of long-term observations.

FURST↗
NASA NTRSDate not supplied

The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) Solar Sounding Rocket Campaign – Calibration and Performance

The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a sounding rocket experiment that is designed to observe, for the first time, soft X-ray spectra of high-temperature, low-emission plasma of coronal structures spatially resolved along a narrow slit.MaGIXS observation involves a set of high temperature spectral lines in soft X-rays from 0.5 - 2.0 keV from an active region core,which will extend the DEM coverage from 3MK to 10MK constraining the slope of the DEM fall-off. The novel instrument designincludes a Wolter-I type telescope and a 3-optic grazing-incidence spectrometer. The spectrometer consists of a finite conjugatemirror pair and a blazed planar, varied line spaced grating, which disperses the rays on to a CCD and provides a high spatial andspectral resolution. Component level instrument testing, integration of the instrument and end-to-end X-ray calibration are carriedout using the X-ray and Cryogenic Facility (XRCF) at NASA Marshall Space Flight Center. MaGIXS is scheduled for launch in2021. We will present the results of X-ray calibration tests for MaGIXS and discuss the expected inflight performance throughdifferent solar observation scenarios.

P. S. Athiray↗