Running head: CREW TRANSIT VEHICLE SYSTEMS
Crew Transit Vehicle Systems
Camryn Burley
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Crew Transit Vehicle Systems
A goal for the near future is to send humans to Mars to establish a long-lasting human
presence there. In order to practice using the systems, technology, and other training necessary to
carry out such a daunting operation, this mission proposes to set up a human colony on the
moon. For the first phase of the mission, setting up the colony and transporting inhabitants there,
using existing technology, is the focus. Eventually, as technology has been developed, the actual
mechanisms that will carry humans to and sustain their life on Mars can be tested with this
colony. This mission will serve to expand human presence in space, give valuable insight and
experience for an eventual mission to Mars, and carry out some of the facets of the cancelled
NASA program Constellation (Wilson, 2007), making it an important undertaking for today.
This report concentrates on getting the first humans to the colony, using equipment and
machinery that has already been developed, exploring the propulsion and landing, guidance, life
support, crew accommodations, communication, and emergency systems of the Crew Transit
Vehicle (CTV).
The propulsion system will allow the craft to exit Low Earth Orbit (LEO) and will get it
on track to reach the moon, and the landing system will allow the craft to touch down on the
surface of the moon. The propulsion system for this mission is based off of the one utilized for
the Apollo 11 first moon landing. The third stage of the Saturn V rocket, the S-IVB employs
both liquid hydrogen and liquid oxygen, as well as a J2 engine, which provides enough thrust to
move the CTV out of LEO and into a lunar transfer orbit (Bell, 2014). After the CTV has
reached the moon, it will need to make use of the landing system. To absorb the shock of landing
on the surface of the moon, crushable aluminum honeycombs will be installed on the four legs of
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the landing gear. They have been tested and can absorb the amount of energy necessary to
cushion the CTV’s landing (Kelly, 2001).
The guidance system allows the CTV to be controlled during flight, by computers and the
crew. This system, again based on that used in Apollo 11, is made up of three main subsystems:
inertial guidance, optical, and computer (Jones, 2013). The inertial guidance subsystem collects
data about changes in the position and velocity of the vehicle and helps steering commands to be
created. Navigational and angle measurements are taken by the optical subsystem. The computer
subsystem uses the data from the other two subsystems to make position, velocity, and steering
commands. The main display console houses all of the necessary buttons and controls for the
crew (Jones, 2013).
The life support system provides for the air, food, water, waste management, and thermal
protection of the crew in the CTV. New technologies, more efficient than even those abord the
International Space Station (ISS), are ready or almost ready to be implemented in spacecraft, and
this mission will utilize them once they are fully avaible, helping to test the latest equipment for
future missions, potentially to Mars. A Temperature Swing Adsorption CO2 Compressor (TSAC)
has been chosen for use. It is more efficient, as it closes the air loop, than the mechanical
compressor currently being used for air revitalization (Dino, 2008). Ample food storage space
for the journey to the moon will be included, but since this is merely a transport vehicle to a
colony, which will have its own food set-up, no out-of-the-ordinary preparations must be made.
As for water recovery, another important element of the life support system, the Vapor Phase
Catalytic Ammonia Removal (VPCAR) has been selected. The VPCAR is a cutting-edge
technology that uses a single step to recover water, and it is advantageous in that it needs no
consumables or any maintenance for about three years (Dino, 2008). An advanced waste-
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processing element will be added to the life support system. The Ames Research Center (ARC)
has developed a new waste oxidation and inceration system that has gone through testing and
was found to produce fewer than the acceptable amount of gas contaminants, making it a
promising, updated technology (Dino, 2008). The final component of the life support system is
thermal protection, which guards the crew in the CTV against extremely low or extremely high
temperatures. An ablative material, which is any of several plastics or polymers that has a very
low thermal conductivity and is also degraded by heat (CRC Press, LLC., 1989), is best served
for this CTV. The thickness of the ablative material will depend on the part of the CTV, being
most abundant on the aft heat shield. The material will be bonded to steel in a honeycomb
pattern, and then insulation is placed underneath. (Pavlosky & St. Leger, 1974). Multi-Layer
Insulation (or MLI), comprised of Mylar and dacron, is used as insulation on the ISS, and is
effective for temperature control and blocking solar radition, making it a good choice for the
CTV. The MLI can trap too much heat, though, and that problem will be solved by installing
heat exchangers and cold plates, which remove excess heat by cooling with a circulation of water
(Price, Phillips, & Knier, 2011).
The crew accommodations system provides space for the crew of the CTV to live, eat,
exercise, and relax, as well as cargo racks for storage. There will be space for the crew to carry
out their daily activities, including mission-related tasks, eating, and other imperatives. The crew
will have trays that fasten to their laps or walls to eat their food (Watson, 2008). As for exercise,
the crew will be provided with a rowing machine, like the one implemented on the space shuttle
(Ryder, 2013), that will be engineered to fold up when not in use, so as not to take up vital space.
The colony will have other provisions for exercise. For sleeping and relaxing, the crew can
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secure sleeping bags to available wall and floor space, or attach themselves to chairs (Fuller
&Trimarchi, 2008).
The communication systems allow the crew to speak with mission control during flight.
Radio waves are commonly used as the communication system in spacecraft and will be emplyed
on this CTV as well. The CTV will have a transmitter and a reciever. Radio waves transmitted
from spacecraft are usually weak once they are received on Earth, so large radio recievers that
are properly aimed will be necessary. Trasmitters from the mission control will also need to be
properly aimed so that the CTV can pick them up (Qualitative Reasoning Group, 2014).
The crew will need emergency systems in place to ensure that they are protected, because
an important goal of any mission is the safety of the crew. These emergency systems include life
support systems, or how to keep the crew alive, and propulsion systems, or how to get the crew
to a safe place after an emergency has occurred. To aid in keeping the crew alive, they will be
outfitted with Advanced Crew Escape Suits (ACES). The bright orange suits are pressurized and
will help the crew survive in an emergency, with air and water, as well as other items such as
flares, medication, and radios (Moskowitz, 2010). The crew will be trained on many emergency
procedures, such as bailout, also to ensure their safety. Since the crew is going to the moon to
start a colony, return should be thought of, but it is not an immediate concern. They will need
safety procedures for if something goes wrong during launch, but reentry is not directly an
element of this particular CTV at this time. Therefore, emergency propulsion systems for reentry
are not considered in as much detail as other safety precautions for this phase of the mission.
Efficient use of the limited space in the CTV is mandatory for ensuring that all of these
systems can be included. The systems work together to provide for the crew and to ensure that
they will make it to their destination, the moon, safely, so as to start the colony outlined in this
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mission. The proper research and development must be put into the propulsion and landing,
guidance, life support, crew accommodations, communication, and emergency systems to make
this mission a success.
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References
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