The Future of Rotorcraft and other Aerial Vehicles for Mars Exploration

Larry A. Young Pascal Lee Edwin Aiken

larry.a.young@nasa.gov pascal.lee@marsinstitute.net NASA Ames Research Center (Ret.)

NASA Ames Research Center Mars Institute, SETI Institute, Moffett Field, CA

Moffett Field, CA & NASA Ames Research Center

Moffett Field, CA

Geoffrey Briggs Gregory M. Pisanich

NASA Ames Research Center (Ret.) gregory.m.pisanich@nasa.gov

Moffett Field, CA KBR Wyle Services, LLC

Moffett Field, CA

Shannah Withrow-Maser Haley Cummings

shannah.n.withrow@nasa.gov haley.cummings@nasa.gov
NASA Ames Research Center NASA Ames Research Center

Moffett Field, CA Moffett Field, CA

ABSTRACT
The Ingenuity Mars Helicopter is a technology demonstrator. The hope is that Ingenuity will one
day lead to future generations of ever-more capable rotorcraft and other aerial vehicles for Mars
exploration and other planetary science missions. This paper builds upon nearly twenty-four years of
Mars rotorcraft and planetary aerial vehicle work at NASA Ames Research Center. It is posited that
a spectrum of different Mars aerial vehicle mission concepts and capabilities could be developed over
the next couple of decades – all of which are now potentially enabled by Ingenuity. A series of
technology challenges or problems are also detailed in this paper. These problems are presented as an
aid in helping establish a nascent planetary rotorcraft or planetary aerial vehicle research community
as well as, maybe, helping realize some of the vehicle/mission concepts discussed in the paper.

2020. It landed at Jezero crater on February 18, 2021.

The launch of Ingenuity was the culmination of a five
INTRODUCTION1 year development effort led by the NASA Jet
The Ingenuity Mars Helicopter was launched Propulsion Laboratory (JPL), NASA Ames Research
along with the Perseverance Mars rover on July 30, Center, NASA Langley Research Center, and the

1 This is a work of the U.S. Government and is not subject to

Presented at the Vertical Flight Society’s 77th Annual
Forum & Technology Display, Virtual, May 10-14, 2021. copyright protection in the U.S.

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industry partner AeroVironment. Ingenuity potentially of Mars -- are defined and updated by Reference
leads the way to new generations of vertical lift Missions initiated by the NASA Human Exploration
planetary aerial vehicles. NASA Ames Research and Operations Mission Directorate, e.g. Ref. 25.
Center has long been a pioneer of Mars rotorcraft and Ultimately, all future Mars rotorcraft missions will
planetary aerial vehicles, e.g. Refs. 3-7. This paper have to both respond to the evolving science and
especially builds upon work in Ref. 10 to consider exploration goals defined in these planning documents
what an overall vision of aerial exploration of Mars as well as be competitively selected against competing
might look like. non-rotorcraft and sometimes non-Mars missions.

The main thrust of this paper is not to present Here on Earth, helicopters are not generally used
‘solutions,’ or advocate for preferred for field research other than transporting scientists and
designs/missions, but rather to pose technology equipment to and from sites that are otherwise difficult
questions (or, rather, problems or challenges) for to access; terrestrial researchers can then gain access
future researchers to consider for the development of by foot to their intended sites to make observations,
future generations of Mars rotorcraft and other measurements and collect samples. On Mars, all sites
planetary aerial vehicles. The Ingenuity Mars are difficult to access and some are exceptionally
Helicopter is not instrumented for science and so the challenging. For example, the walls of the Valles
future potential of such a vehicle that is specifically Marineris (up to 7 km deep) provide a multi-billion-
instrumented for science investigations – a brand new year stratigraphic record that would be challenging to
exploration element – calls for new thinking. Figure 1 access. A rotorcraft with imaging and spectral
presents a high-level roadmap of possible future instrumentation would provide a unique means of
missions that could be supported by Mars rotorcraft. reading this record up close. A rotorcraft with
The general discussion of the paper will be organized specialized instrumentation might even be able to
around this general roadmap. acquire samples from these immense cliffs. It is
noteworthy, though, that there are less challenging
sites where a standalone rover can access the vertical
record of climate history – for example, the Curiosity
rover is currently recording the stratigraphy of Gale
Crater as it slowly climbs Mount Sharp.

More generally, as future Mars rovers like

Figure 1. High-Level Missions Roadmap Perseverance carry out their missions, the support of
an instrumented rotorcraft could safely extend their
reach into sites that challenge a rover’s mobility. At
each site or station that the rover reaches, a supporting
high resolution imaging and spectroscopic survey
KEY SCIENTIFIC QUESTIONS could be carried out to a radius of hundreds of meters
POTENTIALLY ADDRESSABLE WITH THE by a rotorcraft – thereby magnifying and speeding up
AID OF AERIAL VEHICLES the science return. Potentially, samples could also be
Most of NASA’s Mars exploration and planetary acquired from normally inaccessible sites.
science goals are defined from consensus input from
the scientific community. This includes periodic
input from the Mars Exploration Program Advisory POTENTIAL NEXT GENERATION MARS
Group (MEPAG), e.g. Ref. 22, and other science ROTORCRAFT
working groups, e.g. Ref. 23, and Decadal Surveys
NASA JPL and NASA Ames have been jointly
focused on planetary science (there are also other
investigating potential second-generation Mars
Decadal Surveys focused on other communities
rotorcraft since 2019, before even the completion of
supported by programs of the NASA Science Mission
the Ingenuity development. This includes the
Directorate (SMD)) that are sponsored by NASA and
Advanced Mars Helicopter (AMH), Ref. 11, which is
are organized by the National Science Foundation
an improved performance Ingenuity-sized vehicle.
(NSF), e.g. Ref. 24. Finally, human exploration goals
Larger sized vehicles, on the order of 20-40 kilograms
– including those for the eventual human exploration
with 4-5 kilograms of science instrument payload,

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called the Mars Science Helicopter (MSH), Ref. 12, rotorcraft should travel independently and carry all
are also being examined; Fig. 2. Finally, yet another science instrumentation needed for the duration of the
class of rotorcraft, one especially designed for mid-air- mission or to work collaboratively with a rover or
deployment from an entry and descent aeroshell back lander to mitigate the burden of communications
shell (Fig. 3) so as to explore the Martian highlands of systems, collect and analyze samples, and carry
the southern hemisphere of Mars, called the Mars secondary experiments. Additionally, one of the
Highland Helicopter (MHH), Ref. 13 and 21, is also primary open questions for the science community is
being examined. These potential second-generation that of site selection and which areas are of adequate
rotorcraft continue to be either coaxial helicopter diverseness and uniqueness scientifically to benefit the
configurations, like Ingenuity, or multirotor vehicles most from the flexibility of a rotorcraft vehicle.
such as hexacopter configurations. Mid air
deployment potentially allows a Mars rotorcraft to
successfully reach the higher elevations of the
highlands of the southern hemisphere.

The relatively low bending stiffnesses typical of

larger diameter Mars rotorcraft blades means that they
may be susceptable to large out-of-plane deflections
due to flap bending moments. Aerodynamic damping
resisting these out-of-plane deflections is nearly (a)
negligible for Mars rotorcraft blades because of the
thin atmosphere. Until novel mechanical damping
devices are developed for Mars rotor flap damping,
multirotor configurations show more immediate
promise from a flight dynamics perspective over
simply “scaling up” Ingenuity’s coaxial design
because of improved stability for missions that require
larger payloads. Alternatively, the coaxial
configuration shows promise for working in tandem
(b)
with a larger vehicle, such as a rover, because of its
small stowage footprint. Like any other spacecraft, Figure 2. Mars Science Helicopter: (a) hover-in-
packaging/stowing in aeroshells is a significant ground-effect (HIGE) and hover-out-of-ground-
consideration for vehicle design. Assuming heritage effect (HOGE) CFD predictions
entry, descent, and landing (EDL) systems, the
aeroshell/lander constrains the rotor size and,
ultimately, the vehicle performance for current In addition to enabling vertical takeoff and
designs. landing, hover, and low-speed forward-flight, rotary-
In addition to carrying larger payloads, the range, wings can also enable near-vertical descent and
hover time, and cruise speed can be significantly deceleration. This capability, as applied to planetary
increased from the current state-of-the-art (i.e. science missions, was recognized early in the work of
Ingenuity) by optimizing rotor design and adding more Ref. 38. (Rotary-wing decelerators from reentry
robust and capable power systems. Increased speed capsules and space planes have been studied even as
and range means that many science sites can be far-back as the 1970’s by NASA – including work at
considered for investigations that were not previously NASA Ames – and other researchers from around the
feasible. The potential for modular payloads, that world.) Full or partial of rotary-wing deceleration
could be swapped out at lander-based automated post-release from entry aeroshells is, in fact, being
stations also means that multiple different types of employed by the Johns Hopkins University Applied
science could be performed under one mission. Physics Laboratory (JHU APL), The Pennsylvania
State University (PSU), et al team for the Titan
There are many remaining challenges to future Dragonfly mission, Ref. 37. Rotary-wing deceleration
Mars rotorcraft missions. To define such future has also been recently studied by NASA for future
missions requires discussions that include whether the Mars rotorcraft missions, Refs. 13-21. Undoubtedly

3
more work will follow in this area in the future. Figure flight endurance is still appealing from a future Mars
3, based on the work in Ref.13, illustrates one exploration perspective.
mission/vehicle concept employing rotary-wing
deceleration during entry (aka mid-air-deployment) Figure 4 illustrates CFD results of the original
called the Mars Highland Helicopter (MHH). Mars tiltrotor configuration introduced in Ref. 3. This
figure presents the isosurface of velocity magnitude
for the rotor wakes from the partially-tilted (thirty-
degree nose-down) rotors at a forward-flight speed of
60 m/s.

Figure 4. Mars Tiltrotor (Ref. 3)

Figure 3. Mars Highland Helicopter about to
be released from entry and descent aeroshell back
shell in a mid-air-deployment (Ref. 13); CFD
predictions at a descent velocity of 30 m/s Over the past several years, NASA Ames has
examined other longer range and higher speed vehicles
such as Mars tailsitters, of various forms, e.g. Ref. 17
and Figs. 5-7. In addition to issues regarding stowing
BEYOND-NEXT-GENERATION MARS and deploying such vehicles, there are also challenges
ROTORCRAFT AND OTHER PLANETARY
in providing for acceptable conversion corridors
AERIAL VEHICLES
whereby the vehicle transitions from having its lift
Two of the earliest Mars rotorcraft concepts predominately provided by rotors to that of lift being
explored (Ref. 3) were, first, a coaxial helicopter and, provided by its fixed-wings. This problem is
second, a Mars tiltrotor configuration. The coaxial compounded by the fact that compressible, low-
helicopter was studied the most because of its overall Reynolds number effects tend to reduce the maximum
compactness in both stowed and deployed states. As lift achievable by rotary- and fixed-wing airfoils.
acknowledged in that initial work, tiltrotors, tailsitters, Further, devices such as flaps, slats, and multi-element
and other ‘convertible’ vertical lift aerial vehicles airfoils used for terrestrial fixed-wing aircraft –
suffered from requiring large fixed-wing planform including tiltrotors and tailsitters – do not work as
areas. At the time it was hard to rationalize the self- effectively under low-Reynolds number conditions.
deployment of these types of vehicles on purely Finally, because of the necessity to employ ultra-
robotic missions. Over the years, tiltrotors, tailsitters, lightweight structures for rotors, propellers,
and tiltwing aerial concepts have persisted in the proprotors, and fixed-wings for Mars aerial vehicles,
literature, including work at Ames; e.g. Refs. 17-19. such structures will also tend to suffer from low
bending-moment/torsional stiffness. This, in turn,
might limit the maximum forward speed of highly-
Bigger, Longer Range, Greater Endurance Vehicles twisted rotors in helicopter-mode operation and,
Though a Mars tiltrotor configuration would be additionally, might present aeroelastic dynamic
more challenging to stow and deploy than a coaxial stability issues (such as whirl-flutter-stability) in high-
helicopter, its theoretical longer range and greater speed airplane-mode cruise flight. All of these

4
aerodynamic and structural dynamic issues can
potentially manifest themselves in terrestrial aircraft
but are anticipated to be even more troublesome for
Mars tiltrotor, tiltwing, or tailsitter designs. Still, it
must be emphasized that these challenges should not
ideally deter future work on high-speed Mars
rotorcraft; such vehicles could be, if realized, a
powerful tool for Mars exploration. As the time of
larger EDL systems – and the human exploration of
Mars – approaches, the self-assembly/self-deployment (a)
challenges of such vehicles becomes less critical, as
well. For example, it is not unreasonable to assume
that astronauts or external industrial-type robotic
systems could assist in the assembly of these large
high-speed rotorcraft.

(b)

Figure 6. Ring-wing Tailsitter: (a) hover and (b)

forward-flight
(a)

(a)

(b)

Figure 5. X-wing Mars Tailsitter: (a) hover and

(b) forward-flight

(b)

Figure 7. Elliptical-wing Tailsitter: (a) hover and

(b) forward-flight

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 Alternate approaches to provide higher-speed mobility concept is from Ref. 8 and shown in Fig. 9.
rotorcraft from Mars exploration include the potential This concept switches between level flight – in- and
development of “lift+cruise” multirotor configurations out-of-ground-effect – with short hops provided
(e.g. Ref. 32). The maximum speed for lift+cruise through a combination of impulsive periodic rotary-
configurations (where two separate sets of wing collective/thrust changes as well as, again, pogo-
rotors/propellers are provided with one set dedicated like spring/mass/damper legs.
to providing lift throughout the flight and the second
set dedicated to forward propulsion) is dominated by
the maximum allowable advance ratio of the “lifting”
rotors. Most terrestrial rotorcraft are approximately
limited to advance ratios of ~0.4; it is currently
unexplored as to the maximum advance ratio of a rotor
designed for Mars operation in edgewise rotor
forward-flight. Such rotors have to be ultra-
lightweight and will likely suffer from low flap-
bending stiffness and, consequently, may be limited to
advance ratios below that of terrestrial vehicles.

Hybrid Mobility (Surface and Aerial) Vehicles

Future Mars vertical lift aerial vehicles might also
incorporate hybrid mobility capabilities – i.e. where
ground mobility is merged with flight capability. One
example of that hybrid mobility is found in Ref. 19 and
shown in Fig. 8; in this particular case, rotary-wing
lift/propulsion is combined with “pogo” like motion.
Hybrid mobility would seek to take advantage of the
lower power and potential precision positioning of
ground mobility while still retaining the speed, range,
and ability to fly over uncertain terrain afforded by
flight.

Figure 9. Skim, Skip, Jump, and Fly (Ref. 8)

Another hybrid-mobility enabled mission concept

is the proposed LILI (Long-term Ice-field Levitating
Investigator) mission. This vehicle and associated
mission concept are being independently studied at
NASA Ames. The vehicle is shown with skis/wedges
to reflect exploration of the Martian polar regions but
Figure 8. Pogo Rotary-wing Locomotion could, alternatively, work with free-wheeling wheels
or a combination of wheels and skis. Through a
combination of tilting tandem rotors providing for
tandem helicopter flight as well as forward propulsion
Concepts where aerial vehicles also have some
while on the ground, the vehicle could optimize
level of ground mobility must be trade-studied against:
overall mission energy expenditures by switching
(a) aerial vehicles that carry small ground robots as
between flight and ground modes of operation.
payload/cargo and deploy them upon need or (b)
working in co-equal concert/partnership with larger
ground robots. Another Mars rotorcraft hybrid

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 (c)

Figure 11. Rotors on Wheels: (a) isometric view,

(b) front view, and (c) side view

There are four potential advantages of hybrid

ground-air-mobility systems over purely aerial
(a) platforms: first, the overall mission energy efficiency
can potentially be increased; second, precision
movement/positioning on the surface can potentially
be increased; third, exploration of inaccessible-by-air
terrain features can potentially be realized and, fourth,
ground-mobility is a mode of graceful degradation if
aerial mobility becomes unsustainable at some point
during the overall mission.
(b)

Figure 10. “LILI” Concept: hover/flight

mode and (b) surface mode (with skis versus EXPANSIVE, SUSTAINED ROBOTIC
SCIENCE CAMPAIGNS WITH NETWORKS
possible wheels)
OF MULTIPLE VEHICLES AND SURFACE
ASSETS
Robotic Science Campaigns
Alternatively, it may be effective to simply add
There will be a natural evolution in mission
small electric-motor direct-drive wheels to Mars
design where the single, focused missions of today and
rotorcraft landing legs, e.g. Fig. 11. Weight is always
in the past will be supplanted by a sustained, multi-
a major concern when considering a hybrid-mobility
objective robotic science campaigns along the way
vehicle. Accordingly, such a wheeled Mars rotorcraft
towards ultimately a true expeditionary human
would not be designed for long-range surface transit
exploration of Mars. These next step robotic science
but only for precision ground movement for the final
campaigns present perhaps ideal opportunities to take
couple of meters after landing.
full advantage of aerial vehicle exploration of Mars.
Among other things, they will represent the greatest
challenges in autonomous system technologies,
robotics, and information/data networks.

A largely unexplored enabling capability is to

examine new types of entry, descent, and landing
aeroshells that could accommodate larger and/or
(a) (b) multiple aerial vehicles.

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 16), and finally culminating in full-fledged robotic
ecologies or ecosystems (Fig. 17).

Figure 13. Generic Outpost Mission Profile

Figure 12. Entering Craters to Examine

Recurring Slope Lineae; rotor wake visualization
of an eight-rotor configuration over the sloped-
surface of a crater interior (e.g. Ref. 28)

Additionally, sustained robotic science

Figure 14. Generic Trek Mission Profiles
campaigns can contemplate concatenation of
successive missions/systems to perform
expanding/augmented missions. For example, a rover
that was flown to Mars in one launch opportunity
might be joined by a Mars rotorcraft flown during a
subsequent launch opportunity to augment/expand and
extend the mission life of the older rover robotic
system. This would entail generalizing robotic
explorers’ ability to communicate with other robotic
explorers, in addition to/through orbiters and direct-to-
Earth telecom.
Figure 15. Generic Caravan, or Loose Network,
With time, increasing robotic system – and overall Mission Profiles
mission – sophistication will ultimately transform
Mars planetary science missions from single-mission,
single-robotic-platform endeavors to instead
sustained, integrated networks of multiple platforms
that can explore large expanses of terrain and/or
exhaustively investigate regions of scientific interest.
Such sustained robotic science campaigns will, in turn,
ultimately lead to combined robotic/human
exploration campaigns of Mars. It is reasonable to
anticipate that such sustained robotic campaigns might
evolve over time to various different (from simple to
more complex) campaigns: first, perhaps starting with
outposts (Fig. 13), then proceeding to long-rage solo
or rove/rotorcraft treks (Fig. 14), followed then by Figure 16. Generic Integrated Networks Mission
loose networks of multi-robotic-systems traversing Profiles
between one or more outpost stops (Fig. 15), to
enabling integrated networks of vehicles performing Robotic ecosystems are defined in terms of how
back or forth transits between sites and outposts (Fig, tightly coupled and how sustained the interchange of

8
functionality, data, and resources are across multiple Fig. 4a). Reference 9 considered the deployment of
robotic systems. In terms of both attributes – the fixed-wing aircraft, carrying robotic symbiotes of a
degree of coupling and how much exchange of variety of types (e.g. Fig. 4b), as an extension of the
information/resources – robotic ecosystems represent entry, descent, and landing process. This will be
a level just shy of the automated infrastructure explored further at a high level.
required ultimately for human exploration of Mars.
Robotic ecosystems could be established both prior to,
during, and after the initial human exploration of
Mars.

(a)

Figure 17. Generic Robotic Ecosystems Mission

Profiles
(b)

Figure 18. (a) Fixed-wing aerial explorers as one

part of the entry, descent, and landing process as a
Aerial Vehicles, Robotic Symbiotes, and means of distribution of probes and robotic
Deployed/Distributed Sensor Networks systems and (b) samara rotary-wing decelerator;
Though it is tempting for focus solely on new or one possible micro-probe or robotic symbiote
more capable Mars aerial vehicle configurations (in
the traditional aerospace sense to improve them – i.e.
“higher, farther, faster”) in this paper, it is equally References 9 and 33 discussed the
important to consider them in another context. To reconceptualization of Mars airplane deployment and
fully maximize the utility of Mars rotorcraft, it is flight as being one additional/final stage of the overall
crucial to begin to think of these aerial vehicles as entry, descent, and landing process. Additionally,
‘rotorcraft as robots’ (RAR), e.g. Ref. 20. In this because flight time and range are going to be limited
regard, this paper will discuss networks of Mars resources, novel approaches to searching and
rotorcraft and other robotic systems that exchange distributing (deploying in flight) sensors and robotic
some level of information and functions to accomplish symbiotes were also studied; among those approaches
the overall mission. It will be through such networks were bio-inspired search strategies, e.g. Refs. 6-7.
that expansive, sustained science campaigns (versus This search, find, and distribute (SFD) type of mission
single missions with one, or few, rotorcraft) can be would be enabled, in part, by the foundational
conducted. Such precursor science campaigns could advancements in Mars airplane technologies as
then be followed by human exploration of Mars. established by the NASA ARES Mars airplane
concept (e.g. Refs. 29 and 35). The ARES technology
In addition to Mars aerial vehicles performing development effort proved that efficient aerodynamic
imaging or sensor surveys, they will also perform airframes could be developed that were consistent or
utility missions. Some of those missions would focus compatible with a number of volume/span-efficient
on the transport and distribution of drop probes and wing and tail folds for stowage and deployment from
small robotic ‘symbiotes.’ This will be a role not only an aeroshell. A key ARES milestone was the proof-
for Mars rotorcraft but fixed-wing aircraft as well (e.g. of-concept demonstration of a high-altitude (~100,000

9
feet) release from a stratospheric balloon and the Automated Stations and Multi-Sortie Utility
unfolding/deployment of the wings and tail surfaces Missions
and then the pullout to near-level flight as an Even under the most benign Martian
unpowered glider. This high-altitude Mars airplane environmental conditions, robotic systems on the
balloon drop built, in part, on independent, parallel Martian surface are challenged to merely survive let
‘Mars airplane’ balloon drops, e.g. Ref. 34. The ARES alone maximize their productivity. For example, a
concept used rocket-propulsion but could be adapted large fraction of battery power has to be dedicated to
into incorporating more efficient propeller-driven providing for survival heat during the Martian
propulsion – especially if those propellers could serve evenings and winters. An additional example is that
dual-purpose as rotary-wing decelerators for a portion robotic systems that rely on solar-energy battery
of the vehicle release and descent from an aeroshell. recharging are very susceptible to atmospheric-
conveyed dust covering the solar array cells and,
therefore, reducing the overall available power.

An automated base station – an aircraft hangar so

to speak – to house, maintain, and otherwise support
small Mars rotorcraft, both in aerial scout and utility
roles, could greatly expand mission duration and
capability; refer to Figs. 20-21. As noted earlier, the
struggle to provide adequate battery margins for
vehicle electronics survival heat can be ameliorated
considerably by having the rotorcraft dock, and be
housed, in an enclosed, heated hangar. The
(a) automated base station could accommodate larger
solar cell arrays than could be carried by the rotorcraft
and, so, the hangar could recharge the rotorcraft
quicker. (Hangar retractable coverings could also
protect those station solar cell arrays from long term
exposure to dust.) Finite life batteries could be
swapped out in the automated base station. Science
instruments or other rotorcraft payloads could also be
swapped out. Further, in addition to protecting and
maintaining one or more Mars rotorcraft, such an
automated base station could also protect rovers and
(b) other robotic systems (such as a robotic arm), station-
based instruments, and science processing hardware.
It can be readily imagined that such automated base
stations might allow Mars rotorcraft to survive
Martian winters or extensive dust storms. This, in
turn, greatly increases mission return on investment.
Even if a full-support hangar is not possible, there are
still several advantages of combining an automated
base station with one or more Mars rotorcraft. To
develop such automated base stations will require
significant technology development efforts by
(c) roboticists and information technologists.
Figure 19. Generic SFD Mission Profiles: (a)
straight and fast distribution, (b) grid search and
distribution, and (c) bioinspired search and
distribution

10
 swarm (not physically connected together but
coordinated through a telecom network) of small
vehicles (shown flying at different heights, and
relative vehicle-to-vehicle spacing, while again
showing isosurfaces of velocity magnitude in HIGE).
Finally, Fig. 22c shows a number of small modular
rotorcraft physically connected into a tiled array
(approximately half the rotorcraft rely on tractor type
propellers and half using pusher propellers) flying,
again, in HIGE. External payload pods, with multiple
attach points to the rotorcraft ‘elements,’ would be
added and used to carry the larger loads.

Figure 20. An Automated Base Station, aka

‘Hangar’ with ‘Clam-shell’ Siding/Roof, for Mars
Rotorcraft

(a)

(b)
Figure 21. System flow chart of Automated Base
Stations, aka Hangars, supporting Mars Vertical
Lift Aerial Vehicles

One approach to increase payload capacity is to

use external slung loads supported by two or more
Mars rotorcraft to carry those payloads. This implies
either human intervention to set up the slung load or a
very sophisticated automated system to attach the (c)
slung load. An alternate approach is to consider the Figure 22. One Possible Modular Rotorcraft
use of small modular Mars rotorcraft, physically Configuration: (a) single vehicle ‘element,’ (b)
connected together, to add to an aggregate payload swarm of small independent rotorcraft ‘elements,’
capacity. Figure 22a is a single modular rotorcraft and (c) vehicle ‘elements’ integrated into a
‘element’ (showing isosurfaces of velocity magnitude modular rotorcraft configuration
while hovering in ground effect). Figure 22b show a

11
 There are significant tradeoffs between missions vehicle is accidently flipped upside down, hybrid air
that employ a single large, complex robotic system and ground mobility systems, and maybe
versus those proposed using multiple, small, simple deployment/retraction of tethers from the vehicles.
robots. This is true, as well, for autonomous Mars The necessity and complexity of such novel design
rotorcraft. This tradeoff also depends on the general features would require specific and detailed
character of the mission – as to whether it is to design/mission tradeoff analyses.
principally perform aerial surveys or, alternatively,
use the rotorcraft as utility platforms carrying varied
science payloads that can perhaps be periodically ASTRONAUT ASSISTANTS AND HUMAN
exchanged. Underlying these tradeoff considerations EXPLORATION OF MARS
will be assessments of: risk versus redundancy (both
in terms of vehicle design and mission operations), the References 8, 10, and 14-16 reflect early work on
time criticality to survey/assess multiple sites, and the the concept of aerial vehicles – in particular, rotorcraft
necessity for distributed, interconnected (through as robots – supporting astronauts in the human
telecom) platforms and sensors to meet mission exploration of Mars. In particular, this paper is a
objectives. Such tradeoff assessments would greatly continuation of Ref. 10 in that both papers comment
benefit from developing new system analysis tools and on the near- and longer-term future of Mars rotorcraft.
capabilities specifically tailored to all notional Mars Not only can Mars rotorcraft support robotic science
rotorcraft types and missions. missions but they also potentially have a role
supporting precursor missions for human exploration
The modular Mars rotorcraft concepts discussed of Mars as well as play a key role as astronaut
earlier are also a compromise strategy between a large assistants during that exploration. In addition to Ref.
complex rotorcraft and many small simple rotorcraft. 10, Refs. 14-16 recently also considered this question
By performing on-demand assembly, or disassembly, of Mars rotorcraft acting as astronaut assistants.
of such modular rotorcraft, the complexity and number Finally, one extreme engineering example of Mars
of aerial vehicles can be tailored to individual rotorcraft supporting the human exploration of Mars is
missions. a crewed rotorcraft platform, e.g. Ref. 10.

Novel Environments and High-Risk/High-Payoff Astronaut Assistants

Missions Trying to accomplish productive science and
Low altitude aerial surveys over relatively benign exploration campaigns while operating in a spacesuit
terrain (free of obstacles that might result in collision) will be a major challenge. The utility of small Mars
is only the beginning of possible Mars rotorcraft rotorcraft as astronaut assistants is probable for future
mission flight profiles. Among the many more human missions to Mars. Such astronaut assistants
extreme terrains that such aerial platform could fly could be operated/guided by astronauts from their
over, next to, or even inside the interior of, include: habitats, their crewed transportation rovers, and, yes,
caves and lava tubes, polar out-gassing geysers, cliff from within their spacesuits.
faces, canyon walls, large geological formations, and
crater interiors (with their sloped/unstable surfaces); One of the key paradigms of terrestrial UAVs is
e.g. Refs. 28 and 32. Flights could even intentionally to use these vehicles to perform “dirty, dull, and
attempt to fly during periods of extreme atmospheric dangerous” missions instead of relying on people on
and seasonal conditions such as during: dust storms, the ground or manned aerial platforms to perform such
dust devil formation/propagation, dune Aeolian missions. This problem is compounded by the fact
evolution, and dry- and water-ice formation and that not only will astronauts be encumbered by their
sublimation. suits and/or the limitations of their facilities but also
limitations on their physical strength and endurance
Attempting to fly next to (or into) extreme terrain, stemming from their outbound journey to Mars and
or geological obstacles, will dictate vehicle further physical deconditioning when on the planet’s
configurations that require unique design features such surface due to the lower gravity of Mars compared to
as protective guards for rotors, different landing gear Earth.
geometries, configurations that are still flyable if the

12
 A considerable body of research into human/robot
interactions exists for industrial-type robots. A similar
large body of work has been performed for robots and
UAVs supporting military applications. Only a
limited amount of research into human/robot
interactions have been performed for ‘astronaut
assistant’ applications. Among this limited research is
Refs. 14-16; more work is clearly in order. For Mars
rotorcraft to effectively, productively support
astronauts, it is essential that notional astronaut/robot
interactions continue to be investigated in the future.
(b)
Two fundamental types of interactions have to be
recognized: those where the astronaut who was
operating the rotorcraft and other robots is located in a
habitat or pressurized vehicle and those where the
astronaut is on the Martian surface in a space suit. It
should be noted that Refs. 14-16 focused on rotorcraft
– using commercial-off-the-shelf quadcopter and
multirotor configurations – operations conducted by
researchers in surrogate space-suits at Mars-analog
sites.

(c)
Large Utility Platforms for Sustained Exploration
Campaigns Figure 23. Large Autonomous Utility Platforms:
One of the key challenges of early-generation (a) HIGE, (b) HOGE, and (c) forward-flight at
Mars rotorcraft is their volumetric challenges in 30m/s
stowing and deploying from very confined entry,
descent, and landing aeroshells. The constraints upon
the size and payload capacities of Mars rotorcraft that Crewed Rotorcraft
are a part of standalone robotic missions can be A very speculative type of Mars rotorcraft is that
expected to be relaxed somewhat when human of a crewed rotorcraft for human exploration of Mars.
exploration missions (including immediate precursor Reference 10 briefly examined the possibility of the
staging missions) of Mars get underway. If some rotary-wing transport of a single-occupant, suited
assembly was provided by astronauts then larger, more astronaut. The concept entailed examining a tandem
capable utility-type Mars rotorcraft might be enabled. coaxial-rotor helicopter configuration powered by a
hydrazine, or potentially other monopropellants,
Akkerman-type reciprocating engine (Ref. 40). This
early work is partially supported by recent additional
work briefly summarized below in Figs. 23-25.
Further, advances into thinking as to in-situ-derived
propellants (examples such as methane, hydrogen, and
oxygen) might instead enable bi-propellant, or internal
combustion-type, reciprocating engines and,
therefore, improved propulsion efficiencies.
(a)
Alternate crewed aircraft have been proposed in
the literature. One recent example is Ref. 39, which
proposes a VTOL aircraft using rocket propulsion for
takeoff and landing. As the era of human exploration
of Mars approaches, such design studies – and
tradeoffs between aerial and ground-mobile vehicle

13
types – will gain considerable importance. There will
be two key considerations for evaluating potential
mobility options for astronauts on Mars: first, the
health and safety of the astronauts, and, second, the
productivity of the astronauts in terms of providing
time-saving, effective tools to perform tasks.

Very large aerial vehicles will not only require

some level of manual or semi-automated assembly but
may also likely require on-site component fabrication (a)
using both materials sent from Earth as well as in-situ-
derived materials. The clearest example of this is the
extremely large rotor blades of such vehicles (and/or
wings) that would likely have to be fabricated while
on Mars rather than shipped from Earth.
(b)
Whether such vehicles might or might not be
Figure 25. Mars Crewed Rotorcraft hover in
theoretically feasible, the practical logistics of
ground effect
realizing such vehicles would be extremely
challenging. Alternate solutions, such as crewed
ground-mobile rovers are far more likely. Still, it is
important from a research and development
community perspective to periodically reexamine the
maximum practical size of Mars rotorcraft as new
technologies and mission capabilities are introduced.

(a)

(a)
(b)

Figure 26. Notional Crewed Rotorcraft: (a)

hover out of ground effect and (b) hover in ground
effect

OTHER AERIAL PLATFORMS: MARS

AIRPLANES, (SEMI-) BUOYANT AIRCRAFT
(b) AND (GAS-) HOPPERS
Figure 24. Building Leviathan (astronaut CAD Hopefully, the Ingenuity Mars Helicopter and the
model in foreground from Ref. 26) Titan Dragonfly missions will act as catalyst for aerial
explorers of all types for future planetary science
missions. This potentially includes Mars airplanes,
(semi-) buoyant aircraft including airships and
balloons, and gas-hopper systems. Each of these aerial
systems, in addition to future rotorcraft and vertical lift

14
planetary aerial vehicles, can potentially address 30-31 were among the earliest discussions to consider
unique exploration opportunities. As briefly discussed the use of small autonomous rotorcraft to support not
earlier in the paper, Mars airplanes could potentially only planetary science missions but terrestrial field
be thought of as a means of targeted distribution of science. The aerial imagery from such platforms can
sensor networks and robotic micro-systems. (Semi-) provide context for the science being performed on the
buoyant aircraft also have a long history of conceptual ground. Additionally, specialized science instruments
study – and actual NASA SMD mission proposals – can be integrated into these platforms in addition to
within the planetary science and exploration imaging cameras to acquire unique data. Finally, such
community. Semi-buoyant vehicles may ultimately platforms can – just like planetary rotorcraft – could
find their niche as regional aerial observers. Finally, acquire samples from the ground at sites that are
gas-hopper (using hot- or cold-gas thrusters) platforms difficult to otherwise access.
may become a potential technology bridge between
‘aerial’ exploration of planetary bodies such as Mars,
Titan, and Venus to that of off- or near-surface Terrestrial Extreme Environment Explorers (TE3)
exploration of airless planetary bodies such as Europa, and Sentinel Networks
Enceladus, and the asteroids. Field science campaigns oftentimes occur under
The planetary aerial vehicle research community extreme environmental conditions. In many cases, the
becomes stronger if various vehicle advocates can join science campaigns are adversely impacted by seasonal
together to try advancing the field as a whole. To and other environmental conditions that practically
nurture such a research community, it will be required prohibit year-round or sustained multi-year
to acknowledge and balance the interests of the observations or investigations. To successfully
mission-competition-driven NASA Science Mission employ autonomous aerial vehicles for field science
Directorate (SMD) with the foundational research, or campaigns that are year-round or multi-year will
applied research and technology, approach of the require the development of deployable automated
NASA Aeronautics Research Mission Directorate base-stations that can support/protect those vehicles
(ARMD). Similarly, an efficient but collaborative when they are not flying.
means of drawing in academic institutions into the References 8 and 36 include, among other things,
planetary aerial vehicle research community needs to early conceptual descriptions of TE3 and sentinel
be nurtured. networks.

TECHNOLOGY TRANSFER OPPORTUNITIES

TO/FROM TERRESTRIAL VERTICAL LIFT
AERIAL VEHICLES
As exciting as the potentiality of planetary aerial
vehicles is for supporting planetary science missions,
such mission opportunities will inevitably be
relatively rare. Accordingly, it is important to
recognize that many of the technologies derived from (a)
the development of planetary aerial vehicles will also
be cross-cutting for a number of other fields – such as
terrestrial field science or public service
missions/applications – that could or do employ
vertical lift uninhabited aerial vehicles.

Smart Rotorcraft Field Assistants

Almost every terrestrial field science campaign
(b)
could potentially benefit from small autonomous
rotorcraft assisting those campaigns. References 8 and Figure 27. Sentinel Networks

15
Disaster Relief and Emergency Response, (representatives of our civilization that might even
Environmental Monitoring, and Wildlife outlast us). Such a level of autonomy would only be
Conservation required for perhaps interstellar probes or otherwise
Although the rotor and vehicle aerodynamics will remote multigenerational robotic scientific observers.
be quite different between planetary aerial vehicles This penultimate level of autonomy is not necessary
and terrestrial uninhabited aerial vehicles, many other for the vast majority of plausible Mars rotorcraft
vehicle technologies will be cross-cutting. This missions.
includes autonomous system technology, advances in
avionics and flight computers, robotic systems that can
interact and interconnect with aerial vehicles, novel FUTURE MARS ROTORCRAFT: MISSION
deployable sensors and systems, electric-propulsion ARCHITECTURE AND TECHNICAL
and power-electronics, novel health monitoring and CHALLENGES
thermal management techniques/systems. For
Mission Architectures Challenges
example, one of the key capability demonstrations of
A key theme of this paper is promoting the vision
the Ingenuity Mars Helicopter is the use of solar-
of transitioning from a single mission perspective for
electric propulsion with periodic between-flight
Mars exploration to one of sustained robotic science
vehicle battery recharging. This same general type of
campaigns, which in turn leads to a transition to human
solar-electric propulsion for terrestrial vertical lift
exploration missions. Aerial vehicles are a key
autonomous aerial vehicle will enable longer overall
component of realizing this vision. Further, it has to
mission durations for a variety of terrestrial
be emphasized that not one vehicle size or type is
applications.
going to be sufficient to realize an expansive
Three of the most compelling emerging architecture for both near- and far-term missions.
applications for terrestrial vertical lift autonomous Accordingly, there is considerable room for the
aerial vehicles are: disaster relief and emergency planetary aerial vehicle research and development
response (DRER); environmental monitoring; wildlife community for design innovation and technology
conservation. Reference 24, for example, discusses advancements.
the potential for such aerial vehicles for DRER
Technical Challenges/Problems
missions. Further, it has become commonplace to use
Though the Ingenuity Mars Helicopter will result
multirotor configuration ‘drones’ for aerial surveys of
in key technology demonstrations for the flight in the
disaster sites. UAV’s are already being used for
atmosphere of Mars, to fully realize this vision of
environmental monitoring. With, though, an
aerial vehicles as a critical component of the sustained
improved understanding of the cause and effects of
scientific investigation, and human exploration, of
climate change, advanced autonomous aerial vehicles
Mars there are many advances in vehicle design, and
could also provide major advances in environmental
technology development, required that go well beyond
monitoring. Finally, as well, UAV’s are already being
that demonstrated by Ingenuity.
used for wildlife monitoring for conservation
purposes. Being able to keep such conservation
monitoring vehicles nearby the wildlife populations
and onsite twenty-fours a day, 365-days a year through Next generation Mars rotorcraft:
the use of advance sensors, solar-electric propulsion,
1. Assessing the engineering data, and lessons
and/or automated base stations would enable a
learned, information from the Ingenuity Mars
tremendous expansion of conservation efforts. Helicopter.
2. Development of advanced compressible,
low-Reynolds number airfoils for the tip
Pushing the Boundaries of Autonomous Aerial (and Mach range of <0.9 and Reynolds number
non-aerial) Systems ranges <30,000.
Reference 9 outlined a level of autonomy (LOA) 3. Improved understanding of vertical lift aerial
scale ranging from zero to ten. The penultimate rating vehicles in descent, especially studying the
autorotative, vortex ring, and turbulent wake
of LOA=10 was reserved for robotic systems that will
states.
exhibit the autonomous system capability of being our 4. Development of new structural/dynamic
legates (full surrogates for humankind) or even legacy analysis tools to analyze rotors compatible

16
 with novel high-performance compressible, advanced Akkerman (hydrazine or other
low-Reynolds airfoils. monopropellant) engines; (c) ‘vacuum rated’
5. Development of new rotor control system (pressurized) internal combustion engine
technologies and structural damping motors/motor-generators for very large Mars
mechanisms/approaches to provide for vertical lift aerial vehicles.
adequate rotor control despite the inherent 4. Development of self-deploying or automated
aerodynamic damping of Mars rotors deployment rotors with mid-span hinges for
folding, telescoping blades, and blades with
(partial) flexible blade sections for folding or
reeling into a compact stowed state.
Beyond next generation rotorcraft and other planetary 5. Accelerated cross-cutting development of
aerial vehicles: autonomous system technology for both
aerial vehicles, mission science computers,
1. Development of, and/or study, of multi- and multi-agent robotic systems and
element compressible multi-element airfoils distributed sensors.
for rotors and/or fixed-wing lifting-surfaces. 6. Novel flight control of modular distributed
2. Development of and/or study, of flaps, arrays of rotorcraft to form larger payload
flaperons, ailerons, and other fixed-wing capacity aerial platforms.
control surfaces in the compressible, low- 7. Development of new types of entry, descent,
Reynolds number regimes. and landing aeroshells that could
3. Development of new types of vertical lift accommodate larger and/or multiple aerial
aerial vehicles – beyond that of coaxial vehicles.
helicopters and multi-rotor configurations – 8. Development of novel (ground and flight)
to increase range, speed, and payload control for hybrid mobility robotic systems;
capability. This would include developing potentially requires novel fusion of sensors
hybrid multi-modal mobility solutions. and path/trajectory planning algorithms.
4. Develop new types of fixed-frame ultra-
lightweight structures for wings, fuselages, Astronaut Assistants and human exploration missions:
landing gear, and rotor pylons/rotor-support-
structures. 1. Novel human/rotorcraft interfaces to
5. Expand vehicle/mission design concepts of maximize day-to-day mission flexibility.
novel planetary aerial vehicles. 2. Development of ‘back-pack’ (manually)
6. In parallel, new design analysis tools need to deployable aerial asset for scouting for
be developed, including those that account astronauts performing field science; proof of
for design constraints imposed: (a) by concept testing in analog-sites.
considering stowing and then deploying 3. (Alternatively) development of rover-towed
vehicles from Entry, Descent, and Landing utility carts to transport/deployment Mars
systems; (b) integration and interaction with rotorcraft tailored to be astronaut assistants;
landers, rovers, and automated ground- proof of concept of analog-sites.
stations; (c) integration and interaction with 4. Development of very large aerial platforms
‘robotic symbiotes,’ sensor networks, and that are assembled/deployed through
modular payloads; and (d) incorporating manual/semi-automated approaches.
hybrid multi-modality mobility capabilities. 5. Development of very large ultra-lightweight
rotor with blades that are rigidly joined
together in multiple sections through novel
structural joints, pinning mechanisms, or in-
Expansive, sustained robotic science campaigns: place bonding approaches.
6. Development of modular system to be able to
1. Development of refinement of solar-electric
scale aerial vehicles from the moderate to
propulsion Mars rotorcraft to extend their
very large scale (from tens to hundreds of
mission duration.
kilograms).
2. Development of novel power systems –
and/or ‘hanger’ automated bases – to extend
mission duration beyond a few weeks to
years.
3. Development of novel propulsion systems for
larger vehicles; (a) regenerative fuel cells; (b)

17
Other Planetary Bodies and (Maybe, One Day) opportunities. In particular, as more advanced
Extra-Solar Planets planetary aerial vehicles and missions are
Vertical lift aerial vehicles will be limited to contemplated beyond Ingenuity, higher levels of
exploration of just three (four if you count Earth) vehicle autonomy need to be developed and,
planetary bodies in the Solar System: Mars. Titan, and importantly, demonstrated in relevant environments.
Venus. This is because not only do these planetary The most relevant environments, short of on Mars
bodies have sufficient atmospheres for powered flight itself, is testing in Mars-analog sites on Earth.
but they also have well-defined and/or accessible
planetary surfaces to explore (versus the gas giant
planets who do not). There may well be opportunities Enabling Terrestrial Field Science Campaigns and
for non-vertical-lift vehicles for the gas giant planets, Other Public Service Missions
e.g. Ref. 1. The increased flexibility of planetary Technologies critical to enabling rotorcraft on
aerial vehicles will enable expansive new planetary Mars can be applied to Earth-based field science and
science missions. Additionally, some cross-cutting various other missions as well. NASA technology
technologies from planetary aerial vehicle “spin-offs” are ubiquitous in modern society, and there
development could also find their way into small is no doubt that Mars rotorcraft will contribute “spin-
spacecraft (such as gas-hoppers with cold-gas offs” as well. Rotorcraft as rescue tools, whether as
thrusters) that could explore asteroids and other scouts or as active emergency de-escalation tools, are
planetary bodies without atmospheres. Such cross- already gaining popularity. However, the aerodynamic
cutting technologies include avionics, visual conditions that such vehicles encounter are vastly
navigation and other GNC technologies, ultra- different than typical rotorcraft flight conditions. In
lightweight but high-stiffness structures, and power addition, the accuracy and decision-making of the
electronics. autonomy for such vehicles is beyond current
technological capabilities. However, as Mars
rotorcraft gain popularity and the autonomous
MARTIAN AVIATORS AND PLANETARY technology matures to enable such vehicles to
AERIAL VEHICLE DESIGNERS: HOW TO meaningfully and efficiently explore Mars, such
REALIZE THE FUTURE advances in autonomy will contribute to the ability of
In 2000, NASA Ames, Sikorsky Aircraft, and the terrestrial autonomous rotorcraft as well.
American Helicopter Society International (AHS) (the Similarly, as rotorcraft on Mars enable the
precursor to the Vertical Flight Society) sponsored the exploration of the Red Planet in a greatly expanded
first-ever student design competition on the topic of way, this will lead to the optimization of science tools
Mars rotorcraft. In 2002, NASA Ames and the NASA for use on rotorcraft. A majority of Earth-bound
Office of Education’s Minority University Research rotorcraft science campaigns are limited to utilizing
Program (MUREP) sponsored a student design cameras on the rotorcraft. While cameras allow for
competition on the topic of vertical lift aerial vehicles remote sensing and mapping, they do not enable the
for exploring Titan, Saturn’s largest moon. This was characterization of surface or sub-surface materials.
followed, in 2008, by the last (known to the authors) As science instruments are conceptually designed and
NASA student design competition on the topic of subsequently tested and manufactured for Mars
planetary aerial vehicles, sponsored by the NASA rotorcraft, this will open up the types of science that
Aeronautics Research Mission Directorate. can be accomplished by rotorcraft on Earth as well,
Hopefully, more such student design competitions as Ref 8.
well as fellowships and grants will be enabled by the
acceptance of the vertical lift aerial vehicles for The aerodynamics experienced with flight on
planetary science missions. Mars is vastly different than on Earth, and results in
very low chord-based Reynolds numbers (Re ~103).
The research and development into this aerodynamic
Deriving the Most Benefit from Mars Analog-Site flow regime will increase understanding of the flow
Field Testing regime experienced by Earth-based High Altitude
Mars analog site testing of prototype technologies Long Endurance (HALE) aircraft and micro-air
provide important technology maturation vehicles. As Re decreases, conventional airfoils are

18
less efficient, and the understanding of low-Re flow 2017.
regimes has not been widely investigated prior to
2. Grip, H., Scharf, D., Malpica, C., Johnson, W.,
increased interest in rotorcraft for Mars. Thus, as Mandić, M., Singh, G., and Young, L.A.,
understanding of this flow regime increases, research “Guidance and Control for a Mars Helicopter,”
will be applicable to Earth-based flight experiencing AIAA Science and Technology Forum and
reduced Re as well, resulting in more efficient aircraft. Exposition (SciTech 2018), Kissimmee, Florida,
January 8-12, 2018.
3. Young, L. A., Chen, R. T. N., Aiken, E. W.,
CONCLUDING REMARKS Briggs, G. A., "Design Opportunities and
To fully realize the full potentiality of Mars Challenges in the Development of Vertical Lift
Planetary Aerial Vehicles," Proceedings of the
rotorcraft and other planetary aerial vehicle it will be
American Helicopter Society International
necessary to address numerous technology challenges Vertical Lift Aircraft Design Conference, San
or problems. A number of these key technology Francisco, CA, January 2000.
challenges are identified in this paper. These
challenges are organized in the context of near- and 4. Young, L.A., Aiken, E.W., Gulick, V.,
far-term mission concepts and scenarios. These Mancinelli, R., and Briggs, G.A., “Rotorcraft as
Mars Scouts,” 2002 IEEE Aerospace Conference,
mission concepts and scenarios – as enable by various
Big Sky, MT, March 9-16, 2002.
potential aerial vehicle implementations – are also
5. Young, L.A., et al, “Experimental Investigation
summarized in this paper. These technology and Demonstration of Rotary-Wing Technologies
challenges reflect an opportunity for the nascent for Flight in the Atmosphere of Mars,” the 58th
planetary aerial vehicle research community to Annual Forum of the AHS, International,
broadly and noncompetitively contribute to future Montreal, Canada, June 11-13, 2002
planetary science or exploration opportunities. 6. Plice, L., Pisanich, G., Lau, B., and Young, L.,
“Biologically Inspired Behavioral Strategies for
Autonomous Aerial Explorers on Mars,” 2003
IEEE Aerospace Conference, Big Sky, MT,
ACKNOWLEDGMENTS
March 8-15, 2003
The authors would like to acknowledge the 7. Pisanich, G., Young, L.A., Ippolito, C., Plice, L.,
accomplishments of the JPL, AeroVironment, NASA Lau, B., “Actions, Observations, and Decision-
Ames, and NASA Langley Ingenuity Mars Helicopter Making: Biologically Inspired Strategies for
technology demonstrator team. The authors would Autonomous Aerial Vehicles,” AIAA Aerospace
also like to acknowledge the accomplishments to date Sciences Conference, Intelligent Systems
of the Johns Hopkins University Applied Physics Session, Reno, NV, January 2004.
8. Young, L.A., Aiken, E.W., and Briggs, G.A.,
Laboratory and The Pennsylvania State University
“Smart Rotorcraft Field Assistants for Terrestrial
(and many other team members) Titan Dragonfly New
and Planetary Science,” 2004 IEEE Aerospace
Frontiers mission team. The programmatic support of Conference, Big Sky, MT, March 2004.
Ms. Susan Gorton and Dr. William Warmbrodt is 9. Young, L.A., Pisanich, G., and Ippolito, C.,
gratefully acknowledged. Additionally, the Early “Aerial Explorers,” 43rd AIAA Aerospace
Career Initiative support provided by the NASA Space Sciences Meeting, Reno, NV, January 10-13,
Technology Mission Directorate is also gratefully 2005.
acknowledged. Finally, this paper is dedicated to the 10. Young, L.A., Lee, P., Briggs, G., and Aiken, E.,
memory of Benton Lau, the prototypical Martian “Mars Rotorcraft: Possibilities, Limitations, and
aviator. Implications for Human/Robotic Exploration,”
IEEE Aerospace Conference, Big Sky, MT,
March 2005.
11. Withrow-Maser, S., et al, “An Advanced Mars
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