Proposal:

The objective of FLASH (FLare Activity Stellar Herald) is to obtain close-up images of the photosphere of the star EPS451, monitor it for sunspot or flare activity, and provide other missions with an early warning system for large and dangerous stellar flares. The spacecraft is equipped with wide-angle and high resolution cameras (with neutral density filters, line filters, coronograph, and polarizers), as well as a magnetometer, high-energy particle detector, plasma diagnostics package, and X-ray spectrometer for flare detection and monitoring. FLASH is equipped with heavy radiation and heat shielding against the intense sunlight to be encountered so close to EPS451.

FLASH will be injected into an eccentric polar orbit with semi-major axis of a = 0.15 AU and eccentricity e = 0.2 which will allow a survey of the entire disk of the star. The orbit will carry the probe from a perihelion of 0.12 AU to an aphelion of 0.18 AU. The spacecraft will encounter subsolar temperatures between 738K and 905K, and the choice of a slightly elliptical orbit was made to allow the spacecraft to cool somewhat at aphelion. Naturally, even the small 1 meter-square solar panels will provide more than 10 KW (even at reduced efficiency due to heavy shielding, as the solar constant at .18 AU is 16.8 kW/sqm) which is far more than the spacecraft will require. Some of this extra energy will be used to drive active cryo-coolers to keep the spacecraft electronics and instruments cool.

The heavy shielding is designed specially to protect against solar flares, scorching sunlight, and the high-energy particles that might be encountered so near the star. This mission is scheduled to be the first one to arrive at the EPS451 system, and will provide a watch for sudden solar flares which might disrupt other missions, especially those to the inner planets. Note however that the orbit is slightly outside the orbit of the innermost Planet 1, and thus missions to that planet will have to rely on their own monitors or shielding. The radios onboard FLASH will send a signal on the high-frequency common warning band which will allow other missions to take precautions if they are programmed for emergency protcols.

There are 6 science instruments on FLASH, which fully uses 2 DPUs. The Wide-Field Camera (WFC) will take whole disk image of the EPS451 sun. The high-resolution imager (HRI) is equipped with a filter wheel containing neutral density and narrow spectral line filters to image sunspots, flares, prominences, and provide helioseismological data, polarizing filters, as well as a coronograph to block the light from the disk to try and image the corona. A magnetometer (Mag) will map the solar magnetic field in the 0.12 to 0.18 AU that the spacecraft traverses. A high-energy particle (HEP) detector will analyze the solar wind particles (relativistic protons, electrons, alpha-particles, and heavier nuclei) while the plasma diagnostics package (Plas) will study the plasma propterties (thermal protons and electrons) and plasma waves propagating in the wind. The X-ray spectrometer (XRS) will spot active regions and hopefully provide advance warning of flares. This large suite of instruments will for the first time give us a close-up view of a star other than our own sun.

Personnel and Management Plan:

The duties of the mission team are as follows:

This team will guide the FLASH project through the design and development phase (2 years), spacecraft construction, testing and certification (3 years), and the beginning of the cruise phase (1 year out of 66 years). The onboard AI will take over full control after the first year of flight once the team certifies the performance. The Principal Investigator is responsible for the overall project, as well as the details of the construction of the spacecraft components and contractor liason. The Chief Investigator is primarily responsible for the spacecraft design and development. The Mission Control Officer has primary duties during the testing and certification phase, launch, and has the final say at to when full control is passed to the AI. At this point, control is passed over to the mission monitoring team, as only passive data reception is possible at this point due to light travel-time constraints (the spacecraft is moving away at relativistic speeds). The current Chief Scientists will then be responsible for guiding the science team during the long flight and signal return time (66 years + 65 years or 131 years total). Naturally, it will be team successors who have had team responsibilities passed on to them who will carry out the duties during the actual return of data!

Revised Mission Specifications:

Following the announced mission budget cut from $85M to $75M, the FLASH team elected to descope the High-Resolution Imager (HRI). The mission-critcal Wide-Field Camera (WFC, outfitted with the filter system intended for the HRI) and plasma diagnotics instruments will remain as the focus of the stellar flare monitoring program.

ESP451 Homepage ---

smyers@nrao.edu   Steven T. Myers