'Sandstalker' is a manned, unpressurized vehicle, designed to transport two astronauts plus scientific equipment to destinations anywhere within a 40km radius around the main habitat. It carries a variety of different analysing tools, such as moesbauer-spectrometer etc. plus drilling-devices and - as one of our main features - a device to pack up mars-samples. The vehicle should assist the astronauts as much as possible during their missions, improve their abilities and give them a feeling of comfort and safety. It has the ability to move above most of the marsian "flat" surfaces, resuplies the crew and gives them vital information about their hostile environment. 'Sandstalker's' structure is foldable and very lightweight to safe both room and weight. It's size is (unfolded) about 4m (length) x 3.3m (width) x 1.9m (height) at an astimated mass of 1t (including two fully equipped astronauts). Two of these "mars-buggies" find place in the habitat to ensure mission's success
Powersupply, propulsion and struture
The energy sources are rechargeable batteries mounted on top of the vehicle, above the container. They power all the vehicles components. 'Sandstalker' is a 4WD plus four-wheel-steering, to insure maximized maneuverability. All 'legs' can be moved indepentantely and are built up similiar to a human leg. The hip is attached to the main body, turnable 90° forward and backward. The knee helps keeping the whole vehicle in upright position when moving above rough surfaces and stones. It can bend about 60° in both directions to give the hip-control enough time to lift the whole leg softly above any obstacle. We think it is important to give the astronauts as much comfort as possible during their missions. The wheel itself is basicly a 'common' full-metal construction as known from many other rovers, just improved by some soft structures.
The main processor-units and some of the aggregates are positioned in an eliptic part right behind the seats. It can be removed by sliding down. Handlebars help to carry it, so it can be maintained in the habitat.
Basicly, 'Sandstalker' can move autonomously, controlled by a GPS-like system. Nevertheless, we added some features which allow the crew to alter direction at any time. The trackball at the center console - just between the two seats - allows manual changes by moving the gloved hand above the ball's surface. Also speed can be altered in this manner. Alternatively, waypoints and landmarks can be set through the helmet mounted display just by speech and eye-movement, additionaly by hand movement.
A large variety of sensors ensure that the vehicle will not collide with any obstacle. The leg's movement is completely controlled by the computer.
'Sandstalker' has no seats in common means. Due to improved hard-shell EVA-suits, we found an alternative way to provide seating devices. The astronaut will be lifted up by the whole vehicle. The front-knees bend like a camel, the crew moves into position and 'Sandstalker' moves up again. Two bolts on the astronaut's hip fix him. Thus, the astronaut is sitting in his own suit. The two bolts also work as a human-metabolic-interfaces. Fluids and avionics can be transferred and help saving carried resources on the crew's backpack.
To ensure a comfortable seating position, the vehicle's bumper functions as a stirrup. The backpack is supported by an lightwight iron mesh mounted behind the crew. The astronauts now sit in a comfortable "easy-rider" position, their head above the legs (good sight and no visual "barriers") and the possibility of a greater agility caused by the limited restrictions this concept provides.
Universal Plug In System (UPIS)
Real problems can be caused by incompatible plugs. UPIS combines all different kinds of plugs in one system. Avionics, oxygene, hydrogene, elektricity and water can be transferred by using this one plug. All plugs on the vehicle, the habitat and the EVA should be the same. The plug itself is well covered and will only open when attached. We want to ensure that no marsian dust wastes the plug. A handlebar helps attaching. When attached, a simple turn will fix the plug and transfer can start (see Formula 1, pit-stop!). A LED-light indicates the plug's status. Green blinking for active (transfer), green permenent for finished, blue blinking for error, blue permanent for inactive. Blue seems to be more suitable for a warning and finding the plug - it's a harsh contrast to the red mars-surface.
In the moment, the plug works with the mother-father system. We want to think about a system with equals, so you never need an adaptor. A system similar to two airlocks seems a possible solution but is not worked out yet.
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