ESA Document - Emits - ESA

s
Oxygen tank (fuel
cells): (x 2)
Cryo systems
HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 294 of 422
per tank, two coolers, each 8.3 kg (7 kg compressor, 1.3 kg displacer), consumption 37W
each
MLI: 4.6 kg for each tank
Table 4-14: Synthesis per subsystem
4.3.4.4.2 Overall budget (as introduced to the system)
4.3.5 Power
4.3.5.1 Design drivers
Table 4-15: Overall budget
The environment encountered by the MEV and the specific requirements are completely new for
a space power design. Therefore, the completion of this power subsystem is one of the most
challenging power designs of the coming 20 years. Until now, except nuclear technologies,
power storage and generation were only performed on space applications by: solar cells, batteries
(primary or secondary) or fuel cells. More extended technologies for power storage and
generation have to be considered.
The Martian environment is hostile for power system for several reasons: dust deposit, daily
temperature cycling, diffusion and scattering of the sunlight, high-speed winds, presence of
oxidizing soil characteristics, dust storms, roughness and relief of the landing spot, low solar
irradiance and long eclipse durations.
Several studies dealing with a large range of possible technologies candidates have already been
performed (See [RD4],[RD5],[RD60],[RD62],[RD64],[RD65]…). The conclusions vary from
stray to another.
An important rationale is the fact that the technologies shall be available and qualified only for
2015. Hence, designs that are nowadays still at experimental or even conceptual level are also
considered. Moreover, the expected efficiency increase of the qualified technologies during the
following 10 years can also differ.
This study therefore focuses on:
• the qualified/existing technologies: on the ESA development programmes plan
• other technologies at the current level of confidence