CubeSat
OPAL's mission to deploy daughter-ship "picosatellites" had resulted in the development of a launcher system that was "hopelessly complicated" and could only be made to work "most of the time".
With the project's delays mounting, Twiggs sought DARPA funding that resulted in the redesign of the launching mechanism into a simple pusher-plate concept with the satellites held in place by a spring-loaded door.
Inspired by a 4 in (10 cm) cubic plastic box used to display Beanie Babies in stores,[6] Twiggs first settled on the larger ten-centimeter cube as a guideline for the new CubeSat concept.
[2] The smallest standard size is 1U, consisting of a single unit, while the most common form factor was the 3U, which comprised over 40% of all nanosatellites launched to date.
For very low Earth orbits (LEO) in which atmospheric reentry would occur in just days or weeks, radiation can largely be ignored and standard consumer grade electronics may be used.
Consumer electronic devices can survive LEO radiation for that time as the chance of a single event upset (SEU) is very low.
Spacecraft in a sustained low Earth orbit lasting months or years are at risk and only fly hardware designed for and tested in irradiated environments.
[28] Further considerations are made for operation in high vacuum due to the effects of sublimation, outgassing, and metal whiskers, which may result in mission failure.
Structures often feature soft dampers at each end, typically made of rubber, to lessen the effects of impacting other CubeSats in the P-POD.
Commonly found on nearly all CubeSats are magnetorquers which run electricity through a coil to take advantage of Earth's magnetic field to produce a turning moment.
The biggest challenge with CubeSat propulsion is preventing risk to the launch vehicle and its primary payload while still providing significant capability.
[39] Components and methods that are commonly used in larger satellites are disallowed or limited, and the CubeSat Design Specification (CDS) requires a waiver for pressurization above 1.2 atm (120 kPa), over 100 Wh of stored chemical energy, and hazardous materials.
[40] Small motors may also not have room for throttling methods that allow smaller than fully on thrust, which is important for precision maneuvers such as rendezvous.
Due to this low performance, their use in CubeSats for main propulsion is limited and designers choose higher efficiency systems with only minor increases in complexity.
Small hydrazine fueled motors have been developed,[44] but may require a waiver to fly due to restrictions on hazardous chemicals set forth in the CubeSat Design Specification.
This propulsion method is the only one not plagued with restrictions set by the CubeSat Design Specification, as it does not require high pressures, hazardous materials, or significant chemical energy.
A small number of CubeSats have employed a solar sail as its main propulsion and stability in deep space, including the 3U NanoSail-D2 launched in 2010, and the LightSail-1 in May 2015.
[58] These satellites have a limited surface area on their external walls for solar cells assembly, and has to be effectively shared with other parts, such as antennas, optical sensors, camera lens, propulsion systems, and access ports.
To venture farther in the solar system, larger antennas compatible with the Deep Space Network (X-band and Ka-band) are required.
[70] JPL's engineers have also developed a 0.5 m (1 ft 8 in) mesh reflector antenna operating at Ka-band and compatible with the DSN[64][69][71] that folds in a 1.5U stowage volume.
For MarCO, JPL's antenna engineers designed a Folded Panel Reflectarray (FPR)[72] to fit on a 6U CubeSat bus and supports X-band Mars-to-Earth telecommunications at 8 kbit/s at 1AU.
Such testing provides a larger degree of assurance than full-sized satellites can receive, since CubeSats are small enough to fit inside of a thermal vacuum chamber in their entirety.
[79] On February 13, 2012, three P-POD deployers containing seven CubeSats were placed into orbit along with the Lares satellite aboard a Vega rocket launched from French Guiana.
[82] Five CubeSats (Raiko, Niwaka, We-Wish, TechEdSat, F-1) were placed into orbit from the International Space Station on October 4, 2012, as a technology demonstration of small satellite deployment from the ISS.
[83][84][85] Four CubeSats were deployed from the Cygnus Mass Simulator, which was launched April 21, 2013 on the maiden flight of Orbital Sciences' Antares rocket.
The satellites were: AAUSAT4 (Aalborg University, Denmark), e-st@r-II (Politecnico di Torino, Italy) and OUFTI-1 (Université de Liège, Belgium).
During InSight's entry, descent and landing (EDL) in November 2018,[95] the lander transmitted telemetry in the UHF radio band to NASA's Mars Reconnaissance Orbiter (MRO) flying overhead.
[101] NASA initiated the Cube Quest Challenge in 2015, a competition to foster innovation in the use of CubeSats beyond low Earth orbit.
[103] Participating student teams can experience the full cycle from designing, building, and testing to eventually, the possibility of launching and operating their CubeSat.
[114] No matter how inexpensive or versatile CubeSats may be, they must hitch rides as secondary payloads on large rockets launching much larger spacecraft, at prices starting around $100,000 as of 2015.
