ESA Document - Emits - ESA

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HMM
Assessment Study
Report: CDF-20(A)
February 2004
page 159 of 422
plastic packaging material is overwrapped with a foil material to extend the shelf life (NASA
Food Technology Commercial Space Centre).
Packaging on the U.S. side (considered lighter because of the use of plastics rather than cans)
can be considered 220 g/(day*crew) for Shuttle missions and slightly higher for ISS due to
overwrap films and the additional thermostabilized pouches.
For comparison, food with relatively low humidity content was weighed and the ratio between
packaging and food was established. Test articles were dry ice cream, dried roasted seaweed,
mashed potato powder, instant soup and dried fungi. The average packaging to food ratio was
0.34(kgpackaging/kgfood) for ‘meal size’ ratios.
Based on the dry food demand of the crew of aboout 0.674 kg/(day*crew) and the data obtained
from NASA, the current packaging to food ratio is about 0.33(kgpackaging/kgfood) and for ISS
slightly higher.
Based on this outcome, the study considered 270 gpackaging/(day*crew) based on 0.674 kg dry
food per day and crew and a packing ratio of 0.4). Although this seems high, for a long duration
mission some food will probably be produced in-situ and needs additional packaging as well as
the more stringent demands on the food preservation.
3.3.2.2.6 EVA considerations
Based on the uncertainties regarding the conditions of crew as well as the environment during
trans-planetary flight, the frequency of EVA needs to be kept to a minimum. However,
provisions for emergency EVAs need to be foreseen to be able to recover to more favorable
spacecraft performance. Therefore the capability of performing EVAs during transit has been
implemented.
3.3.2.2.7 Contingency supply
Using a regenerative system it would be sufficient to launch the initial filling of the systems and
the make-up supply depending on the recycling efficiencies. However, it is necessary to provide
the crew with contingency supply if the life support system is failing. In an ideal case the
contingency supply would enable the crew to safely return to Earth. Apart from that, as a result
of the abort analysis it was discovered that no extra contingency is required in the ECLSS system
to cope with these scenarios:
Emergency supply of oxygen: 36 days
Emergency supply of potable water: 10 days
Emergency supply of hygiene water: 5 days
Emergency supply of food: 10 days
Currently, the assumption is that the supply would be sufficient for the crew to overcome the
contingency situation or to determine an alternative consumables supply strategy. It is clear that
these figures may significantly change but they give a reasonable starting point for further
discussions. In addition, this contingency supply shall be accessible from the radiation shelter as
the supply for an eventual stay inside.
3.3.2.2.8 Food production unit (Greenhouse)