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Compton Spectrometer and Imager (COSI)
Mission Overview
The Compton Spectrometer and Imager (COSI) is a soft gamma-ray (0.2 to 5 MeV) observatory designed to: map the 511 keV galactic electron-positron annihilation emission; look for radioactive isotopes (26 Al, 60 Fe, and 44 Ti) that trace the galactic history of supernovae; measure polarization of gamma-ray bursts, compact galactic objects and active galactic nuclei; and detect and localize electromagnetic counterparts to multi-messenger sources such as gravitational wave and high-energy neutrinos for follow-up observations by other telescopes.
COSI consists of a compact Compton telescope that utilizes sixteen, 3-dimensional imaging, high-spectral-resolution, germanium detectors contained within a cryostat. A mechanical cryocooler maintains the detectors are at their cold operating point. The cryostat is enclosed on all sides and bottom by bismuth germanate scintillator detectors that act as an anti-coincidence shield to reduce the background and effectively constrain the field of view to 25% of the sky.
COSI is planned to launch in 2025. It will be placed in low Earth orbit.
Note: Mission information is from NASA's Space Science Data Coordinated Archive.
Spending Summary
| FY 2024 Total | By of FY 2024 | By of FY 2025 | Change from FY 2024 | |
|---|---|---|---|---|
| Obligations | $12.9M | $12.9M | $54.3M | +$41.4M |
| Outlays | $22.0M | $22.0M | $43.0M | +$21.0M |
Comparing Contract Obligations
Running sum of 6 awards. Shows cumulative actual spending by fiscal period. Period 2 represents combined Oct-Nov data (this is a reporting quirk of USASpending.gov). Negative values indicate adjustments or credits. Data last updated: 2026-01-13
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What are obligations? Obligations represent NASA's legal commitments to spend money — contracts signed, grants awarded, and purchase orders issued. Unlike outlays (actual payments), obligations show when spending decisions are made.
Reading this chart: The chart displays cumulative obligations throughout the fiscal year (October through September). The solid line shows the current fiscal year's running total, while the dotted line (when available) shows the previous year for comparison. This allows you to see spending patterns and track whether funding is ahead or behind the prior year's pace.
Comparing Contract Outlays
Running sum of 6 awards. Shows cumulative actual spending by fiscal period. Period 2 represents combined Oct-Nov data (this is a reporting quirk of USASpending.gov). Negative values indicate adjustments or credits. Data last updated: 2026-01-13
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What are outlays? Outlays represent actual cash payments made by NASA. While obligations show when spending decisions are made, outlays show when money actually leaves the treasury.
Reading this chart: The chart displays cumulative outlays throughout the fiscal year (October through September). The solid line shows the current fiscal year's actual spending, while the dotted line (when available) shows the previous year for comparison. This reveals the actual cash flow timing and whether spending is keeping pace with the prior year.