First use of BioMars Experimental Sterile External Suits

Background:

BioMars consists of two experiments, "LiMa" (Life on Mars) and "Track and Trace". The latter one is the first ever conducted quantitative backward forward contamination experiment at MDRS. Various experimental set-ups test the quantity of organic material being carried from the station onto Martian surface as well as from the surface back into the station; additionally, the cross distribution change of material on the EVA suits during EVA activity is measured. Whereas the forward contamination and suit cross-distribution is measured with fluorescent micro spherules, the backward contamination is quantified using sterile cellulose patches attached to sterile external suits. This report describes the first testing of the BioMars backward contamination quantification method, i.e. the first test use of sterile external suits.

First Application:

The AustroMars crew flight plan foresaw the first usage of the BioMars suits for Wednesday, 12th April, afternoon, during EVA # 11. Three crew members were assigned for this EVA: Ch. Kandler, EVA Commander, as only "normally dressed" analogue astronaut, and Ch. Hutsteiner and A. Soucek testing the suits.

The procedure started with a normal suit-donning of the MDRS EVA suits, enriched by the AustroMars medical telemetry devices (heart rate and CO2 measurements). The PLSS was mounted, but not the helmet yet.

After procedure up to PLSS mounting, the two suit-donning assistants G. Grömer and M. Spiss, both in semi-sterile TYVAK suits, prepared the sterile external suits. The team of BioMars around B. Sattler, S. Klammer and F. Selch had constructed, sterilized and packed nine suits in total in Austria, and shipped them to the USA together with 600kg equipment of all other AustroMars experiments. The suit consists of a pair of trousers, a jacket and a PLSS cover, all in substance ABC protection suits1 of the Austrian army covered with silver Mylar foil. The outside of the foil was sterilised, and the parts were separately packed in sterile plastic bags for transportation and storage. For the first test EVA, two packages were used (# 1 and 4). The two assistants had to prepare one test subject at a time, as the procedure of suit-donning was more complex than expected.

First, the crew member had to put on the trouser without touching it and without the trouser being touched by anything else than the glove-covered hands of the assistants – and without touching the ground. What sound easy in terms of every-day life turns out to be quite complex with a space suit and in the narrow environment of an airlock and a 3m² EVA prep room filled with four people. It has to be added that the analogue airlock environment is not sterile; hence the care applied may seem illogical to outsiders. However, one task beside the actual quantification was to test the suit and suit-donning procedure as such. Insofar it made sense to stick to the sterile procedures as close as possible.

"Schutzanzug Leicht" (light ABC protection dress)

After the trousers, the jacket was put upon the test subject, even more complex. It turned out that the large hole on the back, foreseen for the PLSS, could not be used as planned, because the jacket could not be put over the PLSS easily. Therefore the assistants had to cut the lower backside strip of the jacket (and close it again after having slipped the jacket over upper body, head and PLSS of test subject).

Jacket Donning:

When these procedures were finished, a 'nice' side effect could be felt by the crew member wearing the new exterior cover: heat. A. Soucek, who was dressed first, had to wait almost 40min fully suited in the airlock, which was a challenge for his blood circulation. Although not moving, his heart rate was constantly above 100.2

Finally, the PLSS cover was attached by the assistants, who had to come up with some improvised solutions in order to figure out the best and most efficient way to do so. This sub-part of the donning sequence took another 15min approximately.

It has to be said, however, that HR measurements are to be judged carefully as the proximity of various test subjects may give wrong measurements.

Then, the helmet was attached to the PLSS system, closed and fixed. All in all, the procedure for one test subject had lasted 45min (Note: for just one!).

After test subject one had been fully prepared, the sequence was started was subject 2 (Ch. Hutsteiner). Here, a slight learning curve could be seen already (e.g handling of jacket and PLSS cover). Nevertheless, things remained complicate due to restricted space.

The attached helmet and the running air supply system had a cooling effect and helped A. Soucek to wait for Ch. Hutsteiner to be fully dressed. However, the road to enjoy cooling was longer than expected: Concentrating on other mattes, no one had thought of the fans on the left side of the PLSS and so the PLSS was fully covered by the Mylar foil without leaving any hole for air supply. The observation was, however, that still some air went through the foil (or other little holes) as a stream of air could be felt inside the helmet, even though much weaker than usual. Originally, A. Soucek thought of the overheating as reason for less felt air, but luckily M. Spiss discovered this "trifle" half way through the suit-donning of test subject 2.

Heat made the donning procedure a challenge for the test subjects…

Airlock Depressurization Procedure:

The inner hatch was closed at 16:25, starting EVA # 11. The airlock sequence went nominal, but the heat augmented another factor, as three people stood next to each other on 2,5m² for 10min. Both test subjects were a bit worried about the coming activities under the afternoon desert sun, but interestingly, when the outer hatch was opened, the situation improved – it became cooler under the suits!

Weather situation during EVA: Clear sky, sunny. Crew experienced very strong winds from SE.

The first suit problems started during the airlock procedure: Whenever Ch. Hutsteiner moved his arms, the attached patches fell off. Collecting them again and attaching them back onto the sterile suit was a challenge for his colleagues due to the EVA gloves. After each successful "rescue operation", it took just one minute until the same patches fell off again. When the outer hatch was opened and Ch. Hutsteiner stepped into the wind, he lost another patch which could not be collected (it was blown away).

The Suit Testing During EVA:

One immediate observation was that the arm length of the external suit was not sufficient. The sleeve got stuck at the O-rings of the normal EVA suit, thus the arms could not be fully stretched. Also, the usual movement with the right hand to the VOX button attached at the left side of the helmet proved to be impossible. Instead, the test subjects had to do this with their left arm, which lead to wonderful acrobatics.

The medical telemetry box usually attached to the left arm was not used during this EVA, except for Ch. Kandler. It was not sterile, and the question was whether the signal from the chest belt would have been transmitted properly through the Mylar foil.

Another problem concerned the water supply: The Plathapus water supply bag could not be used, as the Mylar foil covered the PLSS. This, however, is easy to change for the next test. Due to this fact, Ch. Kandler had to give water at regular intervals to his colleagues.

Opposite to the expectations, the moving ability was quite good (except the arm problem). However, actions like bending or quick movements were not possible. The experienced moving capability could be best compared with a diver in old times, walking on the bottom of the sea with plummet and attached to a rope. The care in walking and acting might be as well explained by the first-time experience and the psychological barrier not to destroy the "fragile" suit3 by fast movements.

In order to test the suit extensively, the crew took the ATVs to drive in the vicinity of the hab. Again, opposite to expectations, the handling of the ATV was easy and worked well. The sitting position was not much different to normal EVAs, however the non-sufficient arm length could be felt at times. The head wind was a problem for the exterior suit when driving a bit faster, as the wind immediately started to tear off loose parts of the suit.

Patches falling off continued to be a problem especially for Ch. Hutsteiner. The reason for this divergence between the two sterile external suits has not been found yet. The patches were not applied by the same assistant for each of the two test subjects. Also, after falling off once, the same patch kept falling off again. Maybe the punctual force possible to apply with the EVA gloves is not high enough.

In fact, the suit is less fragile than seems, as the basis is an ABC protection dress; the silver Mylar foil is only a second layer attached to the main suit.

The biggest "enemy" during EVA # 11 was the strong wind. Needless to say that especially the PLSS cover (as separate foil) was at risk. Accordingly, until the end of the EVA, most of it was destroyed.

End of EVA & Additional Observations:

EVA # 11 ended at 1815. The entire water supply of Ch. Kandler was used up, the test subjects were quite exhausted, although the EVA itself was not stressful and also one of the shortest EVAs so far.

It was extremely important to have one crew member without sterile exterior suit among the EVA team, to help in various situations (re-attaching patches, checking suit exterior, checking med telemetry, etc.).

The problem with patches falling off should be easy to solve by enlarging the adhesive part and paying more attention to fixing the patches properly during suit-donning procedures.

All in all: EVA Crew # 11 and assistants could successfully perform the first testing of the sterile external suits. There is room for improvement, and we are looking forward to the second test EVA.