A shock‐tolerant thermal enclosure has been designed for use in distributed landed missions. Missions such as Pascal and the Mars Long‐Lived Landed Network require low power sources capable of surviving an omnidirectional load at impact and delivering reliable power for several Martian years. With the use of a radioisotope heat source and a thermoelectric converter, power can be generated reliably, but the challenge of developing an insulating canister that delivers sufficient power at end of life and is shock tolerant has been elusive. We describe a manufacturable design using conventional materials that meets mission requirements and show preliminary analysis of impact load response. © 2004 American Institute of Physics