Today we really got to know our space suits by undertaking a four person walking
endurance EVA. The plan was to walk a circuit consisting of a three waypoints.
The first was 'North Hills' 1.16km North of the hab. The second was 'breakdown',
the site of our ATV problems East of the first way point, and the third was
'brain rock', South of way point 2 and about 1.34km east of the hab.
Our plan was to leave the hab at 9:30, and keep walking the circuit until just
before sunset, to get an idea of what distances are feasible in the suits. We
equipped ourselves with water bottles that would allow rehydration without
removing the helmet, and even a cereal bar that could be manoeuvred to our
mouths at lunch time.
We entered the airlock at 9:50am, having (as always) taken longer than expected
to get all the suits adjusted satisfactorily. We made our way to our first
waypoint, arriving at 10:30, and spent approximately 15 minutes taking samples.
However we were not able to communicate with the hab from this location, and
Christiane had to climb to a nearby ridge before we could report in. This was
achieved at 11:17, allowing us to continue to our second waypoint. At 11:59 the
hab called the EVA asking for our position, and we had to stop for a while to
respond. Twenty minutes later we arrived at our second waypoint and commenced
the sampling and permafrost experiment practice.
At 12:44 we second waypoint, and headed for brain rock. At 1:35 we reached a
point 200m from brain rock, but as it was a mountainous feature, it was another
thirty minutes before we located the waypoint position on the side furthest from
the hab. We left brain rock at 14:37 and headed back in the direction of the
hab, arriving at 15:08. We took the opportunity to have the hab place radio in
the airlock so that we could swap one that I had been having trouble
transmitting with. At 15:25 I decide that there was just time to proceed back to
waypoint 1, and then directly back to the hab to arrive before nightfall, so we
departed the hab again. We reached reached North Hills again and return to the
hab arriving at the airlock at 16:39.
So what did we learn? Fitness is important. Not just for the usual reasons that
apply when walking normally, but even more so in a space suit. Fitness effects
how soon you start to breath heavily, and when I started to breath heavily, my
helmet started to mist up very quickly. Especially in the cold morning air. The
other problem is that when physical exertion causes heavy breathing, it is
because more oxygen is needed, and it is much more difficult to get ones breath
back in the restricted environment of a space helmet. The fans in the backpack
only deliver so much air. And as the day gets on and the batteries lose power,
the air flow decreases significantly.
The best idea seems to be to walk at a leisurely pace so as not to become too
tired. When doing that, the spacesuit is not too much of an impediment. I did
have trouble with my radio transmissions in the bulky gloves. I think there was
a problem with the first radio, but even with the second which seemed to work, I
frequently failed to press the transmit key effectively. This may be a problem
that can be avoided with the VOX option, which I have not tested yet.
In the end, we had covered about 12km in six and a half hours, stopping at three
sampling points for up to about half an hour each. I expect the younger and
fitter members of the EVA team could have gotten further than I did, but hiking
in a space suit is definitely harder.