H. COST

The HESSI team has been refining this mission concept for several years and fully understands the requirements, design implications and cost of the investigation. After HESSI’s selection as an alternate in the MIDEX program, the NASA Office of Space Science challenged the HESSI team to develop a mission at SMEX cost able to meet the HESSI/MIDEX minimum science goals. The team together with the GSFC SMEX office produced the HESSI-Lite mission, which was presented to the Associate Administrator in January 1997, but was not started because of launch vehicle problems and other pressures on the budget.

The HESSI-Lite design is the basis for this HESSI/SMEX mission. Table H-1 lists the simplifications. All new technology development items, such as LIGA grids, have been deleted. Recent improvements in GeD performance from developments at UCB allowed us to delete the Si detectors. GSFC’s cryogenics group has flight-qualified an inexpensive cryocooler, and UCB has proven its compatibility with GeDs.

Table H-1 HESSI-SMEX Simplifications

The number of RMCs and GeDs is reduced from 12 to 9, and identical grids are now possible for the front and rear trays. With the 12 SiDs eliminated, the cryostat is simpler, and together with a more capable cryocooler and less heat load, the GeDs can be maintained much colder, enough to survive the radiation dose of an inclined orbit. Thus, the costly equatorial launch, the on-orbit propulsion system, the equatorial ground station, and communications costs, have been eliminated.

The spacecraft is built from already designed and qualified subsystems. Finally, the schedule is trimmed to reflect a greatly simplified system, now composed of mainly heritage designs.

Instrument

This category includes costs for management, science support, systems engineering, instrument systems, and instrument integration. The fabrication costs are based on FAST and Polar, with separately itemized GeD and grid cost based on the HIREGS and HEIDI programs.

Spacecraft

The spacecraft provider, Spectrum Astro, estimated the effort using a grass-roots method, itemizing the known cost of each qualified subsystem and its manpower. During the selection process, the cost for the spacecraft concepts received from the four industry finalists fell between $8 and $12M.

MSI&T

MSI&T costs are based on the FAST program, assuming a comparable effort for HESSI. Included are spacecraft and launch vehicle integration costs for Spectrum Astro.

Operations

Preps costs are grass-roots estimates based on FAST. Costs of writing and testing data display and analysis software was estimated on the SDAC experience at handling similar requirements for SMM, Yohkoh, BATSE, and SOHO. Included also are $300K for ground-based observatory upgrades.

Ground Data System

The Ground Data System cost is based upon the FUSE LEO-T cost, the GSFC cost for the ITOS system used for FAST, and actual costs of FAST database creation and CD production equipment.

MO&DA

The MO&DA costs are based on a grass-roots estimate, based on known FAST, Yohkoh, and Wind costs, assuming a 2-year operations lifetime and 3 years of data analysis. They include science operations, data analysis and distribution, maintenance for the LEO-T, and $500K to fund a US Guest Investigator program.

Budget Reserve

The budget contains a development reserve of 20% on all components of the program, except launch and MO&DA. This is more than ample, given the maturity of these efforts.

Responsible NASA Official: Brian Dennis Web Design: Merrick Berg

Solar Physics Laboratory, Goddard Space Flight Center

Space Science Laboratory, University of California Berkeley

Responsible Berkeley Official: Hugh Hudson Systems Admin: Jon Loran

This page last updated: June 27, 2011