Situation du cryostat à hélium superfluide pour vol embarqué de la "Mission relativity".

The world's largest capacity helium flight dewar has been assembled for use on the Relativity Mission, also known as Gravity Probe-B (GP-B). Acceptance tests have been successfully performed and the dewar has been delivered to Stanford University. The science mission dewar is the first piece of flight hardware delivered for GP-B. It will be used in testing to demonstrate payload functionality with a prototypical Science Instrument Assembly, the flight spare probe (Probe-B), and prototypical electronics. The paper reviews the key design features of the dewar, especially those driven by the ultralow magnetic field requirements. The measured mass, helium boil-off, and ground hold performance are compared to those of the previously launched superfluid helium cryostats (IRAS, COBE, and ISO).