The Mars EVA suit design

With Mars as the current flavour of the month, I have been looking via
google around sites concerned with the design of the Mars eva suit for
when we eventually go there. All the sites were fairly interesting
but none seemed to answer a fairly simple question I have regarding
the Mars eva suit design that I have wondered about for sometime, and
that is how was the astronaut going to put it on and get into the
thing.

If the suit is going to be a polymer body hugging soft suit then it is
a reasonably simple exercise as the astronaut will put it on like a
heavy duty body stocking feet first, but all the paintings and NASA
illustrations I've seen show the Mars suit to be a full pressure suit.

The Apollo eva suits had IIRC a series of zippers, and Neil, Buzz and
the other guys entered the suit from the front, but they were one time
suits, and zippers are not very airtight. The shuttle eva suit comes
in a two-part construction joined at the middle, but a suit for Mars
with that design would most probably be a nightmare to maintain.

The Russians have an eva suit where the entry is via the back with a
door like arrangement, but that to is problematical as it requires
someone else to swing the entry door closed, plus it requires the
person in the suit to double up to get into the thing as they have to
put their legs in at the same time as they duck and put their head and
arms in at the same time.

I would have a Oxygen Nitrogen mix at 12lb psi so no prebreathing is
required, as in an emergancy the suit would need to be put on asap.

My design on the back on an envelope and pondering idea while I'm
doing other things is to combine the shuttle and Russian design. You
have a pants lower section like the shuttle eva suit, but have it high
up to chest bone hight like a fisher man/woman waders, the top section
is hinged back by 90 degrees, think of the upper part like on a small
plane whose canopy swings up and back. The astronaut goes up a ladder
type frame and via a T [inverted] roped device lowers themselves into
the pants section putting their arms in once their feet are at the
bottom, once comfortable, they then just reach up and lower the top
section with it's attached helmet down, and an airtight 0 seal like on
a tupperware box is secured with a two clamps on the chest plate
section and one each on each shoulder part of the suit.

My design has the pants section and life support backpack as one
single unit, and all connections don't need to be concerned with the
door design of the Russian eva suit or needing to be attached together
like in the shuttle eva suit.

Comments, criticisms anyone?

In article ,
Christopher wrote:
If the suit is going to be a polymer body hugging soft suit then it is
a reasonably simple exercise as the astronaut will put it on like a
heavy duty body stocking feet first...

If you're thinking of the Space Activity Suit, no, putting it on is not
particularly simple, because it's necessarily a very tight fit.

but all the paintings and NASA
illustrations I've seen show the Mars suit to be a full pressure suit.

That's the orthodox party line. Left undiscussed is the question of how
a classical suit can be made light enough for sustained wear on Mars.
(Even the Apollo suits would probably be too heavy.)

(NB, all suits even vaguely appropriate for use on Mars are full pressure
suits -- that is a technical term with a specific meaning.)

The Apollo eva suits had IIRC a series of zippers, and Neil, Buzz and
the other guys entered the suit from the front, but they were one time
suits, and zippers are not very airtight.

Zippers can be adequately airtight, and those suits were reusable a fair
number of times, in the absence of lunar dust. (Their expected working
life in the presence of lunar dust was short -- joints, visors, etc. were
giving trouble at the end of the 3-day stays of the later Apollos.)

The Russians have an eva suit where the entry is via the back with a
door like arrangement, but that to is problematical...

Actually it's generally considered a superior design. A new US suit for
shuttle/station use would almost certainly work the same way.

...as it requires someone else to swing the entry door closed...

With *any* current suit design, a helper is very useful.

I would have a Oxygen Nitrogen mix at 12lb psi so no prebreathing is
required, as in an emergancy the suit would need to be put on asap.

NASA and the Russians would both *love* to have a no-prebreathing suit.
It isn't sheer stupidity that has prevented this. Nobody has been able to
make a classical fabric suit whose limbs are adequately flexible with that
much pressure inside them.

None of these suits is something you can put on quickly. Emergencies have
to be handled otherwise.
--
MOST launched 30 June; science observations running | Henry Spencer
since Oct; first surprises seen; papers pending. |

(Henry Spencer) writes:

In article ,
Christopher wrote:

[...]

The Russians have an eva suit where the entry is via the back with a
door like arrangement, but that to is problematical...

Actually it's generally considered a superior design. A new US suit for
shuttle/station use would almost certainly work the same way.

...as it requires someone else to swing the entry door closed...

With *any* current suit design, a helper is very useful.

True, but it's worth noting that the Russian EVA suits do not REQUIRE a
helper; they can be donned and doffed without aid (I believe there is a
strap and lever arrangement to do the job). Like Henry said, a helper
is very useful, especially for the parts on back, and I'm sure they use
help any time it's available.