UAS Spacecraft - Design and Conceptual Proposal
Author: Dr. Michael Zimmer
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Unmanned spacecraft are uncrewed robotic crafts suited for spaceflight. Unmanned spacecrafts have human input that allows for various levels of autonomy (Quadrelli, 2015). These levels of autonomy are pre-programmed functions that are not executable unless instructed. As unmanned spacecraft have evolved, this paper will investigate the purpose, design, and functional design of the Impactor, the International Sun-Earth Explorer-3 (ISEE-3) and the Ulysses. Assessing on these unmanned spacecraft successes, this paper will propose a new conceptual design that holds protective, communication, and energy features.
Historical Analysis
Impactor (1959)
Purpose. The Impactor was an unmanned spacecraft that was part of a series of Russian robotic spacecrafts. Under the Luna Probe program these unmanned spacecrafts were developed to either orbit or land on the moon. The Impactor performed many moon experiments to study its chemical composition, gravity, and climate (Zak, 2021).
Design. The Impactor was designed to collide with the Moon’s surface. As the Impactor approached the moon’s surface images were transmitted back to Earth. The Impactor then selected a crash site with the intention to transmit data before impacting with the Moon’s surface (Orloff, 2004). Unfortunately, the Impactor missed its crash site and transmitted alternative data.
Functional Design Assessment. The Impactor’s goal to become the first spacecraft to escape Earth-Moon system, orbit and collide with the Moon’s surface was achieved (Siddiqi, 2018). The Impactor’s design was the simplest of the Luna Probe spacecrafts. The Impactor did not require a reverse propulsion system or a moon collision guidance system.
International Sun-Earth Explorer-3 (1978-1985)
Purpose. The ISEE-3, also known as International Cometary Explorer (ICE) was an unmanned spacecraft developed by NASA and ESRO/ESA. Under the International Sun-Earth Explorer program (ISEE) these unmanned spacecrafts were developed to study the Earth’s magnetic field and solar wind. The ISEE-3 mission held two missions. First, it studied gravitational fields in the halo orbit. It also passed through a comet’s plasma tail. The ISEE-3 completed its gravitational field mission in 1982 and passed through the Giacobini-Zinner comet plasma tail in 1985 (Stelzried, Efron, & Ellis, 1986).
Design. The ISEE-3 was designed to be the first artificial object to be placed at the Sun-Earth Lagrangian point. At this point, the ISEE-3 orbited to study the suspension between gravitational fields. The ISEE-3 held a special rotational axis that was perpendicular to the ecliptic. This allowed for the continuation of experiments while producing solar power to communicate with Earth (Robertson, 2014). Upon the completion of its mission, the ISEE-3 ejected itself from the Earth-Moon system with a trajectory toward Giacobin-Zinner comet.
Functional Design Assessment. The ISEE-3 was not equipped with cameras as it carried 13 instruments to measure particles, waves and plasmas. The ISEE-3 was covered in solar panels around its barrel cylindrical shape (Cowing, 2014). Four antennas were used to allow for different axis of communication. The ISEE-3 generated 173-watts to power payload and its data handling system.
Ulysses (1990-2009)
Purpose. The Ulysses was a robotic space probe developed by NASA and ESA. The Ulysses was a solar observational probe developed to orbit the Sun and study its latitudes. The Ulysses served a second unintended purpose as a comet observer (Poletto & Suess, 2013). To achieve a multi-perceptive reading of the Sun, the Ulysses scanned the Sun from three different orbits.
Design. The Ulysses was deactivated in 2009 as it operated four times its design lifespan (Carney, 2015). The probe was design in the shape of a box with a dish antenna and radioisotope thermoelectric generator as its power source. The Ulysses spun on a z-axis to coincide with its antenna axis during thruster burns. Based on payload, the Ulysses had to be divided into two sections, one for loud and the other for quiet components. The sectional separation was prompted by component sensitivity. The probe was able to withhold both heat and cold temperatures.
Functional Design Assessment. The Ulysses used S-band and X-band for communication. S-band served the Ulysses to uplink and downlink telemetry while X-band was for science downlink. The Ulysses had dual 45mb tape recorders to store scientific data. The Ulysses’ commands were processed through multiple computer systems that allowed for the multi-use of CPUs, microprocessors and data processing units (Elsner et al., 2005). The scientific instruments onboard the Ulysses were dependent on these computer systems.
Proposed Conceptual Design
Unmanned spacecrafts are designed with specialized features to allow for maximum performance as objects in space hold unique properties from one another. Because of cost, needs have formed for unmanned spacecrafts to have multipurpose functions. Currently, NASA is working to standardize its rovers. Under NASA proposed conceptual design, their rovers will hold both rover (land) and rotor (air) capabilities. The rover will be equipped with quadcopter rotors while also having individual wheel suspension to allow for complete freedom of movement. Under this proposed conceptual design, the Dragonfly will be NASA’s first rover and is estimated to be launched in 2027. The Dragonfly is targeted to reach Titan nine years following its launch. Currently the Dragonfly’s design is externally flawed as components will be exposed to Titan’s elements. As Titan’s climate and terrain will direct the Dragonfly’s mode of movement, a spherical shell will aid to combat external elements that may affect Dragonfly’s components. Externally, this added feature will appear to be a ball with retractable rover and rotor capabilities. Often NASA crafts will either have a dipole or dish antenna. Spherical antennas are an evolving concept. This concept is made possible through a spiral electrical wrap allowing for 360-degree frequency transmission. Furthermore, traditional rovers use flat solar panels to power its craft. As solar technology has evolved, spherical micro solar cells are possible. To power the rover/rotor ball design, spherical micro solar cells will be embedded into the rover’s outer shell. A spherical shell design will hold protective, communication and energy benefits that aligns will NASA rover standardized goals.
Conclusion
Conceptual design elements of unmanned spacecrafts must be simple while configured in a way that serves multiple functions (Alfriend, 2010). In addition, unmanned spacecrafts must withhold the durability of elements that affects spacecraft component functionality. NASA engineers continually seek for methods, materials and structural design to improve performance while extending a spacecraft’s life span. It is common for spacecrafts to be re-missioned following the completions of its intended objectives. According to Howell (2021), "extended missions leverage NASA's large investments, allowing continued science operations at a cost far lower than developing a new mission" (para. 9). When this occurs, engineering best-practices are formed and often replicated into future spacecrafts. Proposing a spherical outer shell for future rovers is a conceptual design that is realistic. If a spherical design is implemented, rovers will hold superior features compared to its predecessors.
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References
Alfriend, K. (2010). Spacecraft formation flying: Dynamics, control and navigation (1st ed.). Butterworth-Heinemann.
Carney, E. (2015). A deathblow to the Death Star: The rise and fall of NASA’s Shuttle-Centaur. Science. Condé Nast. https://arstechnica.com/science/2015/10/dispatches-from-the-death-star-the-rise-and-fall-of-nasas-shuttle-centaur/
Cowing, K. (2014). Lost and Found in Space. The New York Times. The Opinion Pages.
Elsner, R., Lugaz, N., Waite Jr, P., Cravens, T., Gladstone, G., Ford, P., Grodent, D., Bhardwaj, A., MacDowall, R., Desch, M., & Majeed, T. (2005). Simultaneous chandra X ray, hubble space telescope ultraviolet, and ulysses radio observations of jupiter's aurora. Journal of Geophysical Research - Space Physics, 110(A1), A01207-n/a. https://doi.org/10.1029/2004JA010717
Howell, E. (2021). NASA extends planetary science missions at Mars and Jupiter. Spaceflight. Future US, Inc. https://www.space.com/nasa-extends-mars-insight-and-jupiter-juno
Poletto,G., & Suess, S. (2013). The Sun and the Heliopsphere as an Integrated System. Springer Science & Business Media. ISBN 9781402028311.
Orloff, R. (2004). Extravehicular Activity. Apollo by the Numbers: A Statistical Reference. NASA History Division, Office of Policy and Plans. The NASA History Series. Washington, D.C.: NASA. ISBN 978-0-16-050631-4.
Quadrelli, M., Wood, L., Riedel, J., McHenry, M., Aung, M., Cangahuala, L., Volpe, R., Beauchamp, P., & Cutts, J. (2015). Guidance, navigation, and control technology assessment for future planetary science missions. Journal of Guidance, Control, and Dynamics, 38(7), 1165-1186. https://doi.org/10.2514/1.G000525
Robertson, A. (2014). Spaceship come home: can citizen scientists rescue an abandoned space probe?. The Verge.
Siddiqi, A. (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016. The NASA history series, 2nd. Washington, D.C.: NASA History Program Office. p. 1.
Stelzried, C., Efron, L., Ellis, J. (1986). Halley Comet Missions. NASA. pp. 241–242. TDA Progress Report 42-87.
Zak, A. (2021). Planetary Spacecraft – Moon Missions. Spacecraft Planetary Lunar.
http://www.russianspaceweb.com/spacecraft_planetary_lunar.html
