12 research outputs found
Thermal Protection System Requirements for Future Planetary Entry and Aerocapture Missions
Thermal protection systems are a critical component of planetary exploration,
enabling probes to enter the atmosphere and perform in-situ measurements. The
aero-thermal conditions encountered during entry are destination and vehicle
dependent, ranging from relatively benign conditions at Mars and Titan, to
extreme conditions at Venus and Jupiter. The thermal protection system is a
single-point-of-failure for both entry probe and aerocapture missions, and
hence must be qualified using ground tests to ensure mission success. The high
density Carbon-Phenolic which was used in the Galileo and the Pioneer Venus
missions is no longer available due to the lack of the manufacturing base for
its raw materials. To address the need for Venus and outer planet missions,
NASA has developed the Heatshield for Extreme Environment Entry Technology
(HEEET). The present study uses the Aerocapture Mission Analysis Tool (AMAT) to
perform a comparative study of the thermal protection system requirements for
various planetary destinations and the applicability of HEEET for future entry
and aerocapture missions. The heat rate and stagnation pressure for aerocapture
is significantly less compared to probe entry. The large heat loads during
aerocapture present a challenge, but HEEET is capable of sustaining large heat
loads within a reasonable TPS mass fraction.Comment: 14 pages, 12 figure
Planetary Entry Probe Dataset: Analysis and Rules of Thumb for Future Missions
Since the beginning of robotic interplanetary exploration nearly six decades
ago, successful atmospheric entry has been accomplished at Venus, Earth, Mars,
Jupiter, and Titan. More entry probe missions are planned to Venus, Titan, and
Uranus in the next decade. Atmospheric entry subjects the vehicle to rapid
deceleration and aerothermal loads which the vehicle must be designed for, to
deliver the robotic instruments inside the atmosphere. The design of planetary
probes and their mission architecture is complex, and involves various
engineering constraints such as peak deceleration, heating rate, heating load,
and communications which must be satisfied within the budget and schedule of
cost constrained mission opportunities. Engineering design data from previous
entry probe missions serve as a valuable reference for designing future
missions. The present study compiles an augmented version of the blue book
entry probe dataset, performs a comparative analysis of the entry conditions,
and provides engineering rules of thumb for design of future missions. Using
the dataset, the present study proposes a new empirical correlation which aims
to more accurately predict the thermal protection system mass fraction for high
heat load conditions during entry and aerocapture at Uranus and Neptune.Comment: 15 pages, 15 figure
A Low Cost Mars Aerocapture Technology Demonstrator
The ability to launch small secondary payloads to Mars on future science
missions present an exciting opportunity for demonstration of advanced
technologies for planetary exploration such as aerocapture. Over the years,
several aerocapture technology demonstration missions have been proposed but
none could be realized, causing the technology to become dormant as it is seen
as too risky and expensive to be used on a science mission. The present study
proposes a low-cost Mars aerocapture demonstration concept as a secondary
payload, and could pave the way for future low-cost small interplanetary
orbiter missions. The proposed mission heavily leverages the mission
architecture and the flight hardware of the MarCO spacecraft for a low cost
mission. The 35 kg technology demonstrator would launch as an ESPA secondary
payload on a future Mars mission, and would be deployed from the upper stage
soon after primary spacecraft separation. The vehicle then independently
cruises to Mars, where it will perform aerocapture and insert a 6U MarCO
heritage CubeSat to a 200 x 2000 km orbit. The mission architecture
incorporates a number of cost saving approaches, and is estimated to fit within
a 30M cost cap, of which 10M is allocated for technology development and risk
reduction.Comment: 14 pages, 9 figure
Launch Vehicle High-Energy Performance Dataset
The choice of the launch vehicle is an important consideration during the
preliminary planning of interplanetary missions. The launch vehicle must be
highly reliable, capable of imparting sufficient energy to the spacecraft to
inject it on to an Earth-escape trajectory, and must fit within the cost
constraints of the mission. Over the recent past, the most commonly used
launchers for interplanetary missions include the Atlas V401, Atlas V551, Delta
IVH, and Falcon Heavy expendable version. The NASA Launch Vehicle Performance
website maintains a tool to help mission planners evaluate various launch
vehicles during mission studies. However, there is no comprehensive dataset
which can be used to quickly compare the launch performance and launch cost of
various options. The present study compiles a dataset of the high energy
performance of existing and planned launchers from open-source data and
performs a quantitative comparison of the launch performance and the launch
cost per kg. The Falcon Heavy expendable offers the lowest cost-per-kg for
high-energy launches, with only $0.075M per kg. The Vulcan Centaur offers
comparable performance to the Falcon Heavy. The results indicate Falcon Heavy
Expendable and the Vulcan Centaur will be the likely choice for several future
missions.Comment: 6 pages, 4 figure
Performance Benefit of Aerocapture for the Design Reference Mission Set
Aerocapture is a maneuver which uses aerodynamic drag to slow down a
spacecraft in a single pass through the atmosphere. All planetary orbiters to
date have used propulsive orbit insertion. Aerocapture is a promising
alternative, especially for small satellite missions and missions to the ice
giants. The large {\Delta}V requirement makes it practically impossible for
small satellites to enter low circular orbits. Aerocapture can enable insertion
of low-cost satellites into circular orbits around Mars and Venus. For ice
giant missions, aerocapture can enable orbit insertion from fast arrival
trajectories which are impractical with propulsive insertion. By utilizing the
atmospheric drag to impart the {\Delta}V, aerocapture can offer significant
propellant mass and cost savings for a wide range of planetary missions. The
present study analyzes the performance benefit offered by aerocapture for a set
of design reference missions and their applications to future Solar System
exploration from Venus to Neptune. The estimated performance benefit for
aerocapture in terms of delivered mass increase are: Venus (92%), Earth (108%),
Mars (17%), and Titan (614%), Uranus (35%), and Neptune (43%). At Uranus and
Neptune, aerocapture is a mission enabling technology for orbit insertion from
fast arrival interplanetary trajectories.Comment: 11 pages, 8 figure
Aerocapture Enabled Fast Uranus Orbiter Missions
At the far reaches of the outer Solar System, the ice giants remain the last
class of planets yet to be studied using orbiters. The 2023-2032 Planetary
Science Decadal Survey has underscored the importance of the ice giants in
understanding the origin, formation, and evolution of our Solar System. The
enormous heliocentric distance of Uranus presents considerable mission design
challenges, the most important being able to reach Uranus within a reasonable
time. The present study presents two examples of aerocapture enabled short
flight time, fast trajectories for Uranus orbiter missions, and highlights the
enormous benefits provided by aerocapture. The first is an EEJU trajectory with
a launch opportunity in July 2031 with a flight time of 8 years. The second is
an EJU trajectory with a launch opportunity in June 2034 with a flight time of
only 5 years. Using the Falcon Heavy Expendable, the available launch
capability is 4950 kg and 1400 kg respectively for the two trajectories. Both
trajectories have a high arrival speed of 20 km/s, which provides sufficient
corridor width for aerocapture. Compared to propulsive insertion architectures
which take 13 to 15 years, the fast trajectories offer significant reduction in
the flight time.Comment: 9 pages, 6 figure
Aerocapture: A Historical Review and Bibliometric Data Analysis from 1980 to 2023
Aerocapture is a technique which uses atmospheric drag to decelerate a
spacecraft and achieve nearly fuel-free orbit insertion from an interplanetary
trajectory. The present study performs a historical review of the field, and a
bibliometric data analysis of the literature from 1980 to 2023. The data offers
insights into the evolution of the field, current state of research, and
pathways for its continued development. The data reveal a pattern in the rise
of publications, followed by a period of stagnation, which repeats itself
approximately once every decade. Mars is the most studied destination, while
Uranus is the least studied. Prior to 2013, NASA centers produced the most
publications and are the most cited in the field. However, academic
institutions produced the majority of publications in the last decade. The
United States continues to be the leading country in terms of publications,
followed by China. The Journal of Spacecraft and Rockets is the leading source
of publications, both in terms of number and citations. NASA is the leading
funding source, followed by the National Natural Science Foundation of China. A
proposed low-cost Earth flight demonstration of aerocapture will greatly reduce
the risk for future science missions.Comment: 19 pages, 20 figure
Aerocapture Design Reference Missions for Solar System Exploration: from Venus to Neptune
Aerocapture is the technique of using planetary atmospheres to decelerate a
spacecraft in a single pass to achieve nearly fuel-free orbit insertion.
Aerocapture has been extensively studied since the 1980s but has never been
flown yet. The entry conditions encountered during aerocapture are strongly
destination dependent, and performance benefit offered by aerocapture is also
destination dependent. Aerocapture is applicable to all atmosphere-bearing
destinations with the exception of Jupiter and Saturn, whose extreme entry
conditions make aerocapture infeasible. A recent study by the NASA Science
Mission Directorate highlighted the need for baseline design reference
missions, as a starting point for system level architecture studies. The
present study uses the Aerocapture Mission Analysis Tool (AMAT) to compile a
list of design reference missions at Venus, Earth, Mars, Titan, Uranus, and
Neptune. These reference missions can provide an initial assessment of the
feasibility of aerocapture for a proposed mission, and provide intial baseline
values for more detailed system studies. The reference mission set provides a
quick estimate of the entry conditions, control requirements, and aero-thermal
loads for architectural level studies.Comment: 12 pages, 7 figure
Comparison of Lift and Drag Modulation Control for Ice Giant Aerocapture Missions
Aerocapture is an orbit insertion technique which uses atmospheric drag from
a single pass to decelerate a spacecraft. Compared to conventional propulsive
insertion, aerocapture can impart large velocity changes to the spacecraft with
almost no propellant. At the far reaches of the outer Solar System, the ice
giants remain the last class of planets to be explored using orbiters. Their
enormous heliocentric distance presents significant mission design challenges,
particularly the large V required for orbit insertion. This makes
aerocapture an attractive method of orbit insertion, but also challenging due
to the comparatively large navigation and atmospheric uncertainties. The
present study performs a comparison of the lift and drag modulation control and
their implications for future missions. Lift modulation provides nearly twice
the entry corridor width as drag modulation, and can thus accommodate larger
uncertainties. Lift modulation offers continuous control throughout the flight
enabling it to adjust the trajectory in response to the actual density profile
encountered. Drag modulation offers much more benign aero-thermal conditions
compared to lift modulation. With drag modulation, there is no control
authority after the drag skirt jettison making the vehicle more susceptible to
exit state errors from density variations encountered after the jettison event.Comment: 7 pages, 3 figure