ESA Document - Emits - ESA
Share Embed Flag
Download ePaper

ESA Document - Emits - ESA

ESA Document - Emits - ESA ESA Document - Emits - ESA

emits.esa.int
from emits.esa.int More from this publisher
06.02.2013 Views

s HMM Assessment Study Report: CDF-20(A) February 2004 page 160 of 422 A greenhouse has not been introduced at this stage of the study. The study team is aware of the positive impact of the greenhouse on the different functions of a LSS, the nutrition of the crew and on the crew psychology. On the basis of preliminary knowledge, a greenhouse would provide:: • A high degree of closure of carbon dioxide to oxygen conversion • A high degree of water loop closure • A high percentage of fresh food to the crew However, it would cause an increase in structural mass and power requirements that perhaps offset the gain of mass on the LSS. Therefore, at this stage of the study and the incomplete tradeoff between LSS with greenhouse and LSS without greenhouse, the greenhouse was not considered. 3.3.2.3 Waste management strategy The long duration of this mission inherently involves the production of substantial amounts of both organic and inorganic solid waste. This amount adds up to several tonness and has to be taken into account and dealt with in an efficient way. Several options were considered for waste management. It was decided to jettison the generated solid waste using existing airlocks to minimise the mass penalties of the mission. However, some treatment and storage is still necessary before jettisoning. This treatment depends on the nature of the waste and can be described as follows. Waste treatment strategy The handling of the inorganic waste (i.e. cleaning supplies, hygiene supplies, waste collection supplies, etc) is somewhat easier than for organic waste as it does not require because much treatment. Care must be taken in correctly classifying the nature of the waste. Supplies classified as inorganic upon launch become organic waste upon use by the crew. The first step in the management of the inorganic waste would be to compact it to reduce its volume. Mass reduction is possible by reducing the waste reusable solid, gaseous and liquid compounds. After compaction, decontamination and bioresistant storage would be sufficient to have the inorganic waste safely stored before jettisoning. The management of the organic waste (i.e. used tissues, faecal material, hair and skin material, nail clippings, food leftovers, etc) is more complicated and it requires waste stabilization. Three main technologies could be used for this purpose: chemical stabilization, sterilization or lyophilization (commonly referred to as freeze drying). Mass and power considerations, and assessing their technology readiness level, lyophilization looks most promising for the reduction of the organic waste. Lyophilization is the process of removing water from a product by sublimation and desorption. It is performed in lyophilization equipment which consists of a drying chamber with temperature controlled shelves, a condenser to trap water removed from the product, a cooling system to supply refrigerant to the shelves and condenser, and a vacuum system to reduce the pressure in the chamber and condenser to facilitate the drying process. Lyophilizers come in a wide variety of sizes and configurations and can be equipped with options that allow system controls to range from fully manual to completely automated. Lyophilization cycles consist of three phases:

s HMM Assessment Study Report: CDF-20(A) February 2004 page 161 of 422 Freezing, primary drying, and secondary drying. Conditions in the dryer are varied through the cycle to ensure that the resulting product has the desired physical and chemical properties, and that the required stability is achieved. This freeze drying technique allows recovery of water, which could be fed to the water recycling system, while inactivating and compacting the remaining solid waste. This treated waste needs to be stored in airtight bags to avoid its humidification and recontamination to be then jettisoned together with the compacted and treated inorganic waste according to the strategy explained hereafter. Figure 3-30 summarizes’ the waste management strategy selected for this mission: Treatment: Lyophilization Airtight Storage Jettison Gaseous Waste Organic Solid Waste Waste Solid Waste Resource Recovery Inorganic Solid Waste Liquid Waste Treatment: Decontamination Bioresistant Storage Jettison Figure 3-30: Waste strategy The MELiSSA cycle could provide an alternative way of treating organic waste. However, its maturity is currently not advanced enough to be considered in this study. 3.3.2.3.1 Jettisoning strategy For the proposed waste management strategy to have an optimal beneficial impact on the mission performances, the stored waste should be jettisoned at strategic mission phases; this is, before any major ∆v manoeuvres to reduce the mass that needs to be accelerated or decelerated. Having this in mind, two waste discarding operations are envisioned: • The first jettisoning would occur prior to the Mars Orbit Insertion manoeuvres and it would discard around 1210 kg of solid waste stored during the 217 days of the transfer to Mars phase. • The second discarding operation would be to transfer the waste stored during the 533 days orbiting around Mars to the MAV after it has docked with the THM and before it is undocked. • The waste accumulated in this phase is calculated to be about 2890 kg, which after treatment and compaction can be stored in the MAV’s cabin. • Finally, the 1170 kg of waste stored during the 210 days of transfer to Earth can remain in the THM and would be discarded with it. Compliant with the Planetary Protection rules, it is necessary to ensure that none of the jettisoned waste units would reach the surface of Mars or Earth.

s<br />

HMM<br />

Assessment Study<br />

Report: CDF-20(A)<br />

February 2004<br />

page 161 of 422<br />

Freezing, primary drying, and secondary drying. Conditions in the dryer are varied through the<br />

cycle to ensure that the resulting product has the desired physical and chemical properties, and<br />

that the required stability is achieved. This freeze drying technique allows recovery of water,<br />

which could be fed to the water recycling system, while inactivating and compacting the<br />

remaining solid waste. This treated waste needs to be stored in airtight bags to avoid its<br />

humidification and recontamination to be then jettisoned together with the compacted and treated<br />

inorganic waste according to the strategy explained hereafter. Figure 3-30 summarizes’ the waste<br />

management strategy selected for this mission:<br />

Treatment:<br />

Lyophilization<br />

Airtight Storage<br />

Jettison<br />

Gaseous<br />

Waste<br />

Organic<br />

Solid<br />

Waste<br />

Waste<br />

Solid<br />

Waste<br />

Resource<br />

Recovery<br />

Inorganic<br />

Solid<br />

Waste<br />

Liquid<br />

Waste<br />

Treatment:<br />

Decontamination<br />

Bioresistant Storage<br />

Jettison<br />

Figure 3-30: Waste strategy<br />

The MELiSSA cycle could provide an alternative way of treating organic waste. However, its<br />

maturity is currently not advanced enough to be considered in this study.<br />

3.3.2.3.1 Jettisoning strategy<br />

For the proposed waste management strategy to have an optimal beneficial impact on the<br />

mission performances, the stored waste should be jettisoned at strategic mission phases; this is,<br />

before any major ∆v manoeuvres to reduce the mass that needs to be accelerated or decelerated.<br />

Having this in mind, two waste discarding operations are envisioned:<br />

• The first jettisoning would occur prior to the Mars Orbit Insertion manoeuvres and it<br />

would discard around 1210 kg of solid waste stored during the 217 days of the<br />

transfer to Mars phase.<br />

• The second discarding operation would be to transfer the waste stored during the 533<br />

days orbiting around Mars to the MAV after it has docked with the THM and before<br />

it is undocked.<br />

• The waste accumulated in this phase is calculated to be about 2890 kg, which after<br />

treatment and compaction can be stored in the MAV’s cabin.<br />

• Finally, the 1170 kg of waste stored during the 210 days of transfer to Earth can<br />

remain in the THM and would be discarded with it.<br />

Compliant with the Planetary Protection rules, it is necessary to ensure that none of the jettisoned<br />

waste units would reach the surface of Mars or Earth.

logo

products

Resources

Company

Terms of service
Privacy policy
Cookie policy
Cookie settings
Imprint
Change language
Made with love in Switzerland
© 2024 Yumpu.com all rights reserved

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!