| Operator: | NASA |
| Manufacturer: | Jackson School of Geosciences and JPL |
| Type: | Ice penetrating radar |
| Function: | Characterize ice shell structure |
| Mission Duration: | Cruise: 5.5 years Science phase: 4 years |
| Mass: | 32.2 kg |
| Dimensions: | Antenna: 16 m (52 ft) |
| Power Consumption: | 55 W |
| Data Rate: | 5 - 80 Mbps |
| Spacecraft: | Europa Clipper |
| Sc Operator: | NASA |
| Launch: | UTC (12:06 p.m. EDT) |
| Rocket: | Falcon Heavy |
The Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) is a multi-frequency, multi-channel ice penetrating radar system that will be flown on board the Europa Clipper mission to Jupiter's moon Europa. REASON investigation will provide the first direct measurements of Europa's ice shell surface character and subsurface structure.[1]
The REASON instrument makes innovative use of radar sounding, altimetry, reflectometry, plasma and particles analyses. These investigations will use a dual-frequency radar emitting HF (9 MHz) and VHF (60 MHz) with concurrent shallow and deep sounding.[1] [2] [3] Both VHF and HF radiating elements are mounted on a single boom, reducing antennamass. The mission plan also includes using REASON as a nadir altimeter capable of measuring tides to test ice shell and ocean hypotheses as well as characterizing roughness across the surface to identify potential landing sites for a future Europa Lander.[1]
The REASON instrument will also be able to spot pockets of water within the ice shell that could serve as a passageway for chemicals on the moon's surface to the ocean below — an environment where life could potentially develop.
The instrument was developed by the Jackson School of Geosciences,[4] and its Principal Investigator is Donald Blankenship.[4] REASON was fabricated by engineers from NASA's Jet Propulsion Laboratory and the University of Iowa.[4]
| REASON | Units/performance | |
|---|---|---|
| Electronics mass | 17.5 kg | |
| Antenna mass | 14.7 kg | |
| Total mass | 32.2 kg | |
| Operating power | 55 W | |
| Antenna length | 16m (52feet) | |
| VHF (shallow sounding) | 300 m to 4.5 km | |
| HF (deep sounding) | 1 km to 30 km | |
| Pulse length | 30 - 100 μs | |
| Operational altitude | 10 - 1000 km | |
| Radar potential | HF | |
| Data rate | 5 - 80 Mbps | |
| Data volume per flyby | 24 Gbits |
The scientific objectives of the REASON investigation are: [5]