Achieving Science with CubeSats Thinking Inside the Box (2016) / Chapter Skim
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5 Technology Development: Current Status and Future Direction
5 Technology Development: Current Status and Future Direction
Pages 55-70
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From page 55... ...
Due to their geometrical and mass constraints, CubeSats provide a unique innovation platform from which to rethink many engineering subsystems, especially in the context of modern developments in integrated sensors, as well as advances in computational and communications technologies. Such development may have important consequences beyond CubeSats for spacecraft of various sizes.1 Table 5.1 presents some of the CubeSat enabling technologies and examples of potential applications derived from Chapter 4's discussion of each science discipline.
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From page 56... ...
Attitude and Orbit Passive, magnetic Reaction wheels, with limited Reaction wheels, de-saturate Determination and system and de-saturation via propulsion systems Control, p. 60 hysteresis Orbit Two Line 2-way ranging.
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From page 57... ...
62 Thermal f Passive Passive and electrical heaters Passive heat-pipes, thermal Electrical Power, louvers, deployable Sun Energy Storage, and shield; new active systems, Thermal Control, e.g., micro-cryocoolers p. 63 Deployable None Solar arrays and UHF/VHF Ka-band antennas, gossamer Deployable Systems, systems dipole antennas structures, and tethers p.
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From page 58... ...
The commercial CubeSat sector is composed of a number of segments, such as the following: • Firms that focus on hardware and software manufacturing and development, including manufacture of components. Current examples include both established and newer firms such as Blue Canyon Technologies, Black Swift Technologies, Maryland Aerospace Inc., Pumpkin Inc., SSBV Aerospace and Technology Group, Sinclair Interplanetary, Tyvak Nano-Satellite Systems Inc., and Tethers Unlimited, Inc., in the United States and Clyde Space, Gomspace, and Innovative Solutions in Space in Europe.
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From page 59... ...
Star trackers, attitude control systems, momentum wheels, transponders, and power supplies are examples of such "stock" items, exploiting economies of scale not available to other space platforms to drive the price point down. However, some long-lead-time items, such as solar arrays, do remain.
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From page 60... ...
Commercial activity has accelerated the development of technologies -- for example, attitude control, making it more robust and reliable for use in science missions. TECHNOLOGY AREAS Attitude and Orbit Determination and Control Attitude Determination and Control Perhaps the most significant improvement in CubeSat technology performance has been in attitude determination and control because this has, in turn, enabled the development and application of other subsystems, such as enhanced communication.
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From page 61... ...
Proposed Science Missions Enabled 2006 2008 2010 2012 2014 2016 2018 Year FIGURE 5.2 Improvement of attitude control capabilities with time. Many scientific missions, especially in astrophysics, would benefit from control below a few tens of arcseconds.
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From page 62... ...
Mobility also complements the capability of CubeSats to control their attitude to the precision required by a particular mission and would be required to dump stored momentum from the reaction wheels for CubeSats beyond LEO, when the magnetic field of Earth can no longer be used. At present, limited mobility options exist without overly penalizing the volume available to the payload.
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From page 63... ...
• Solar sails making use of photon pressure to change the momentum of the spacecraft and enable propellantless mobility with potential applications for deep space CubeSats. Electrical Power, Energy Storage, and Thermal Control Early CubeSats employed body-mounted solar arrays, generating an orbit average power of a few watts per CubeSat unit.
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From page 64... ...
Although the improvement has not been of the magnitude seen in attitude control systems, storage capabilities continue to track terrestrial capabilities; however, peak power levels remain limited by battery discharge rates due to thermal concerns. Thermal Given the power-intensive characteristics and densely packed dimensions of payloads, thermal control can be a critical issue for many science missions; however, as the power density continues to increase, it is likely that thermal control of CubeSats will become even more challenging.
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From page 65... ...
Bottom: NASA Marshall Space Flight Center, "NASA, Industry Partner Test 20-Meter Solar Sail System," July 26, 2005, http://www.nasa.gov/centers/marshall/ multimedia/photos/2005/ photos05-121.html.
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From page 66... ...
16 developed for the NASA ESTO-sponsored RainCube 6U precipitation radar CubeSat (antenna stows within 1.5U) , as well as the USC/ISI-designed 0.5 m deployable antenna that flew on the Aeneas CubeSat as a technology demonstration from which KaPDA was derived.17 Instruments and Sensors The CubeSat form factor, power constraints, and thermal environments offer formidable challenges to the development of sensors that can perform valuable science measurements as part of CubeSat missions.
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From page 67... ...
Of special importance to various science-based CubeSat missions are technologies that require a stable and highly calibrated performance (i.e., for Earth observations) , good thermal stability, especially at low temperatures (i.e., for infrared observations and some microgravity science)
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From page 68... ...
In particular, for constellation and other advanced science opportunities, more capability will be demanded of CubeSat flight software.24,25 There are new efforts to develop provably correct general-purpose CubeSat flight software, such as CubedOS,26 which is intended for use on the Lunar IceCube mission. While experimental, such efforts are trying to advance the leading edge of how CubeSat flight software would be developed.27 Data Handling, Processing, and Autonomy CubeSat development has benefited from the increasing availability of low-cost consumer electronics for data processing and storage.
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From page 69... ...
Consideration is also being given to levels of radiation tolerance as well as mitigation techniques as CubeSat developers begin to develop missions beyond LEO. Within the ground segment, once again the use of commercial hardware and software is more common than in traditional space systems.
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From page 70... ...
Current science data management techniques (tracking instrument health, calibration changes, and anomaly response) do not generally include more than 10 spacecraft.
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