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Microsatellites’ Performances Reaching Commercial Level

The Commercial Space Project Group blog posts will refocus again on the group’s research after the series of publications about SGC13. This post will analyze how the performances of microsatellites have reached a level in which they are commercially attractive.

The miniaturization of components is dramatically expanding the mission capabilities for Nano and Microsatellites. Key performance indicators (resolution, downlink rate…) improve more than an order of magnitude per decade approximating the so called Moore’s law. This is empowering Microsatellites to perform increasingly challenging missions beyond technology demonstrations. Multiple factors have contributed to enhance their performances such as miniaturization of electronics or the availability of low-cost and high-performance electronics.

Nano/Microsatellites present a completely new set of attributes that make them especially appropriate for missions requiring shorter development times, low development costs or short replacement periods due to rapid technology obsolescence.

Many of the satellites in this segment follow the standardized CubeSats frames (U = 1kg and 10x10x10 cm: 1U, 3U, 12U), which lead to easier design and integration. The fact that these satellites usually orbit at LEO (Low Earth Orbit) makes the requirements to support the harsh Space environment less pressing. 30 years ago Surrey Satellite Technology Ltd disrupted the satellite market when demonstrated that the use of COTS (Commercial Off-The Shelf) components was feasible in space. This enabled the design of more affordable satellites without giving up on performance. Moreover, it has permitted to leverage on the R&D investments done in commercial electronics for the mass market. These products are manufactured in high volumes reducing cost, need to have high reliability and their performances far exceeds the ones seen in radiation-hard components. Easier designs and the use of existing technologies lead to reduced manufacturing costs, which opens the market to new customers. More satellites built reinforces the standard CubeSat platforms allowing manufacturers to establish batch production processes again lowering costs. Some satellite manufacturers have even developed pre-assembled spacecrafts significantly reducing development times. All these factors minimize the economic loss in case of mission failure, which at the same time reduces investment risk, insurance costs, and launch cost (reliability is less critical and economies of scale).

GSD

Fig. 1: Evolution of Downlink Rate & On-Board Storage in SSTL Delivered Satellites: 1.a) Absolute Value; 1.b) Specific Value

Key enabling technologies for Microsatellites have witnessed a tremendous evolution. Because of the use of COTS components, some sub-systems have followed Moore’s law. Downlink rate and storage capacity have increased more than an order of magnitude every decade. GSD (Ground Sampling Distance) has been evolving following a similar trend (Fig. 1.a & 2.a). Specific performances have grown an order of magnitude per decade (Fig. 1.b & 2.b). 10 years ago, to achieve a resolution of 1m a satellite in the 1 ton order of magnitude was necessary; today, such resolutions can be achieved with satellites in the 100kg order of magnitude.

Downlink rate

Fig. 2: Evolution of GSD in SSTL Delivered Satellites: 1.a) Absolute Value; 1.b) Specific Value

This trend hasn’t reached its limit with new breakthrough technologies coming. As electronics shrink and increase performances, more power need to be created in the reduced exterior area of Microsatellite platforms. Tests on multilayer solar cells have reached efficiencies up to 44%. Shape memory alloys will soon permit reduce mass, volume and cost of deployment mechanisms.

Nano/Microsats still have some limitations. There is some room for improvement in some sub-systems like the AOCS (Attitude and Orbit Control System) in nanosatellites that will allow them to deploy new concepts like formation-flying. Key technologies to perform beyond-LEO missions are still to be developed (thermal control, laser communications…). LEO orbits present some challenges such as lower visibility times over local targets leading to the need for bigger constellations. Increasingly crowded orbits and Space debris certainly pose a collision risk for LEO constellations. Finally, the lack of a dedicated Microlauncher limits their capacity to select launch date, orbit or the development of advanced concepts like formation-flying or distributed architectures.

Despite some challenges still need to be solved, the performances of microsatellites are improving at a very rapid pace. For some applications like Earth observation, microsatellites have reached a performance level at which they can be commercially competitive with bigger platforms.

Additional details can be found at Palerm, Barrera & Salas; MICROSATELLITES AND MICROLAUNCHERS – THE TANDEM THAT WILL DISRUPT THE SATELLITE INDUSTRY, IAC-13-E6.1.9. This paper is the winner of the Space is Business Competition organized by the International Astronautical Federation’s (IAF) Entrepreneurship and Investment Committee (EIC) in cooperation with the Space Generation Advisory Council (SGAC).

This article expresses the opinion of the authors alone; it does not represent the official positions of any organization or company, including Space Generation Advisory Council or the authors’ employer.

by Lluc Palerm