(Top Left: Johns Hopkins Applied Physics Laboratory engineers test the solar arrays on the ORS Tech 1 cubesat. Photo courtesy of John Hopkins University Applied Physics Laboratory)
PEO Space Systems is working with other Navy organizations in the development of an emerging low-cost space technology – nanosatellites. The Naval Research Laboratory developed some of the first military nanosatellites and it continues to develop technologies such as miniature solid propellant thrusters, environmental monitoring sensors and automated satellite operations software. The U.S. Naval Academy and Naval Postgraduate School also are heavily involved in developing nanosatellites.
Nanosatellites are less than a foot long and weigh less than 25 pounds. A common form factor is the CubeSat, which was developed as a low-cost means to teach university students how to develop space systems. CubeSats were originally 10 centimeters on each side and weighed less than a kilogram. That size was later called one unit or “1U,” and larger sizes were developed. Now 3U is common and many organizations are building 6U or larger satellites.
Nanosatellites are launched into orbit when a larger satellite mission has spare room, similar to riding on a space-available airline flight. Once the primary space mission separates from the launch vehicle, the nanosatellites are deployed from a spring-loaded canister. More than 100 were launched in both 2013 and 2014 and hundreds more nanosats are in development by academic, commercial and military organizations.
PEO Space Systems, with support from SPAWAR Systems Center Pacific, is developing a 3U CubeSat called Integrated Communications Extension Capability, ICE-Cap. After launch in 2016, the system will be the first satellite of its size to demonstrate the ability to communicate through the Mobile User Objective System to send data directly to the warfighter. ICE-Cap also will show the ability to relay communications from a disadvantaged user near the North Pole to another sailor halfway around the world. ICE-Cap leverages technology from five different Small Business Innovative Research (SBIR) projects funded by PEO Space Systems.
Radar altimeters are currently used to provide key information about the ocean, measure the sea surface height and wave height, and wind speed. In January 2015, PEO Space Systems, SPAWAR Systems Center Pacific and the Naval Research Laboratory began a study to evaluate the impact of nanosatellites on ocean modeling.
As a baseline for the study, the team created a Miniature Altimeter Payload (MAP) design, including a 6U satellite bus with a radar altimeter. The study showed that the use of nanosats could provide an increase in effectiveness with a minimum cost increase. As a possible next step for the MAP program, a nanosat demonstration mission could verify the ability to build a radar altimeter mission to meet the performance studied.
The Vector Joint Capability Technology Demonstration launched two satellites to orbit in November 2013 to test advanced communications capabilities. The system was evaluated by a combatant command for potential operational use. The satellites successfully demonstrated the communications mission before de-orbiting in April 2015.
(Artist redering of the ORS Tech 1 cubesat in flight. Illustration of Johns Hopkins University Applied Physics Laboratory)
The High-bandwidth Anti-jam LPI/LPD Optical Network (HALO-Net) project is developing an optical communication system that will enable low size, weight and power, secure, anti-jam, low probability of intercept / low probability of detection (LPI/LPD) downlink and crosslink optical communications for a CubeSat-sized platform. The intent of the HALO-Net project is to deliver assured communications in a radio frequency-constrained environment. However, the retro-reflector can also be used for precise orbit determination using laser ranging techniques, a key capability for radar altimetry systems.
On July 28 2016, the optical retroreflectors in the HALO-Net risk reduction payload passed shock testing. Shock testing was required to validate the survivability of the delicate optics during spacecraft separation from the launch vehicle. Shock occurs and propagates through the spacecraft when the pyrotechnic device(s) are fired to release the spacecraft from the upper stage.
The Space and Naval Warfare Systems Center Pacific (SSC Pacific) Nano-Satellite Tracking Experiment (NTE) is a project co-sponsored by the Space Experiment Review Board (SERB) to develop and test a passive RADAR retro-reflector to improve the ability to track cube-satellites and nanosatellites with ground based RADARs. A retro-reflector will reflect incident RADAR pulses back toward the source, regardless of the incidence angle. The RADAR return of nanosatellites outfitted with retro-reflectors will be compared to the return of similar sized nanosatellites without retro-reflectors to demonstrate improvement in tracking ability.