Entry, Descent, and Landing: EDL is one of our biggest challenges. The
revolutionary sky crane landing system used for the Curiosity rover placed just
under 1 mt of payload on the surface of Mars. The smallest viable humanscale lander concept is more than an order of magnitude larger, and it may
be necessary to land multiple 20-30 mt payloads at a human landing site.
Consequently, a completely new approach is needed for human-scale EDL.
For instance, supersonic retropropulsion may be necessary to provide safe
and accurate atmospheric entry, descent, and precision landing on Mars.
Ascent from Planetary Surfaces: A Mars Ascent Vehicle (MAV) is required
to transport crews from the surface to Mars orbit. The MAV drives lander and
EDL requirements, which in turn impact in-space propulsion and the total mass
launched from Earth, a major driver for mission cost. Current MAV designs
require a minimum lander size of just under 20 mt, assuming propellant can
be generated from the Martian atmosphere via ISRU. The MAV is also critical
to crew survival, requiring additional reliability and redundancy, zero boil-off
cryogenic storage, and limited maintenance during years of dormancy. Current
studies continue to refine our understanding of this critical element.
Communication and Navigation: Currently, Mars robotic rovers have
data rates around two million bits per second, using a relay, such as the Mars
Reconnaissance Orbiter. The ISS data rate is 300 million bits per second, two
orders of magnitude faster. Future human Mars missions may need up to a
billion bits per second at 1,000 times greater range than ISS, requiring laser
communications to reduce weight and power. In addition, disruption and
error-tolerant interplanetary networking and improved navigation capabilities
are required to ensure accurate trajectories and precision landing.
Working in Space
Even with 50 years of human operations in space, new capabilities are
necessary to sustain productive operations for crew and robotic systems
at multiple destinations within the cislunar and Martian environments.
Exploration Extravehicular Activity: New EVA systems must supply
basic biological needs during spacewalks, provide protection from hostile
environments, and enable comfort, flexibility, and dexterity to support
human exploration and investigation of new worlds. These EVA
systems will be integrated and tested with vehicle interfaces, such as
suitports, using lower-pressure, higher-oxygen atmospheres (e.g., 8.2
pounds per square inch with 34 percent oxygen) for rapid and frequent
EVAs with minimum loss of valuable atmospheric gasses. The
Asteroid Redirect Crew Mission will be an early opportunity in the
Proving Ground to validate new EVA systems when crews conduct
spacewalks to collect samples of an asteroid boulder. The potential
effects on human health resulting from surface dust and its safe removal
will also need to be thoroughly understood.
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