Since the start of 2015, there has been progress of sorts in the Mars One project. The applicants have been whittled down to a group of 100 and the long awaited study by Paragon on the habitat life support systems has been made available. And then there is the study carried out independently last year by MIT.
But there are also shifts in the project definition, in the timing and in the fund raising model. Here we look at the Paragon study. Later posts will look at the selection process, followed by some comments arising from the MIT study, and take at look at the changes in the Mars One plans.
The Paragon Study
In March 2013 Mars One contracted the US company Paragon Space Development Corporation to carry out an initial conceptual design study of the Environmental Control and Life Support System (ECLSS), as well as the Mars Surface Exploration Spacesuit System. On their website, Paragon state that the scope of the study included identifying major suppliers, as well as existing concepts and technologies that can be used as the basis for further development.The Paragon ECLSS concept design assessment can be downloaded from the Mars One web site, and it is to the project’s credit that the report has been made public.
The report runs to 52 pages, and is authored by Barry Finger, Gary Lantz and Tad Tehno, two aerospace engineers and a mechanical(?) engineer. An initial draft was given to Mars On in May 2013 as a basis for discussion, the final version was issued in May 2015. Two years in the making.
The first section of 4 pages includes a section on the scope of the report, a couple of pages outlining the background and phasing of the Mars One project and a list of references.
The first point to note is what this report is not.
It does not cover the spacesuit system, it does not identify major suppliers nor (to any significant degree) does it identify appropriate life support technologies; there is no overview or discussion of the available technologies. The report explicitly excludes consideration of the collection and removal of regolith, electrical power production, and consideration of crew functions such as lighting, food preparation, fire suppression and radiation protection. Is it ‘an initial conceptual design’? That phrase can be used to mean all most anything. We will return to what this report is and is not later.
The next seven pages cover ‘System-Level Design Drivers’. This briefly goes through the Mars environmental conditions (air composition, pressure, temperature range, the general nature of the regolith) and makes some remarks about design requirements (launch mass and volume are important, the life support system should be simple to operate, sufficient instrumentation, minimum maintenance , need for reliable power) . There are also statements about the (non) use of biological systems, and a nod to future possible use of ‘3D-printing’.
The next 23 pages of Section 3 goes through the habitat requirements, defined in two sections as pre- and post- crew arrival, giving the current assessment of the capacity requirements for each system within the life support system. This is preceded by a list of functional requirements, the wording of which is somewhat curious in places. Each requirement is followed by a brief rationale. There are about 4 pages of this.
There is much commonality between the pre- and post- crew arrival requirements and sections of the report, including a table on water quality requirements, are simply repeated verbatim, the repeated material amounting to perhaps 2 and half pages of text. In addition, the same paragraph explaining the rationale for buffer storage is repeated, verbatim, some seven times in the report (one page contains this paragraph 3 times in successive sections). This alone adds another page to the report length. There are other examples of where blocks of text are simply repeated.
Some of the post crew arrival specifications seem confused, with two sets of ‘nominal’ figures for sensible heat removal and latent heat removal. The layout, and general verbosity of this entire section, along with the lack of any summary makes it difficult to get an overview of the system requirements.
The final page of section 3 lists a series of standards, many of which are repeats of the reference list given in the opening part of the report.
Section 4 begins with a schematic (Figure 4) of the ‘ECLSS Functional Layout’. This is followed by five pages that describe each of the five functional areas shown in the figure. There is then a section giving the basis of the ECLSS sizing for post crew arrival operation (oxygen and gas use, potable water use, estimated heat generation, throughput of regolith and Mars atmospheric gas).
Table 10 in section 4.3 gives the estimated mass and volume of the life support system component units. The origin and basis for these estimates is not given. The body of the report gives the volume of most of the storage vessels as ‘TBD’ – which we take to stand for ‘To Be Determined’ (Paragon omit to tell us their actual definition); but Paragon must at least have taken a guess of the volumes and weights for all storage vessels to come up with the numbers in Table 10.
Section 5 makes a number of generalized statements about general design requirements and steps that can be taken to minimize risk.
Mars - Alluvial Fans [credit - NASA]
M1101-0915
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