CASE STUDY: NITESat

VIIRS imagery of Chicago and Milwaukee

A Nanosatellite to Study Light Pollution

A research and educational institution is developing a program to study and characterize light pollution in the Midwestern United States, centered on Chicago. This program offers an opportunity to make a marked increase in our understanding of the effects of light pollution on our environment and particularly the loss of the night sky. They determined that a nanosatellite mission to capture high-resolution, three-color, night time imagery of the region from orbit would produce valuable data for this study.

Previous attempts to characterize nighttime illumination relied on data products primarily from two instruments, the Operational Line Scanner (OLS) flown since the 1970s, and more recently the Visible Infrared Imaging Radiometer Suite (VIIRS).  Although the data from these instruments were valuable to light pollution researchers, measuring nighttime illumination was not their primary mission.  Data provided by these instruments suffered from numerous shortcomings, including a relatively low ground resolution (742m/px), absence of onboard calibration, light saturation in highly populated urban centers resulting from standard operation at a high gain setting, the blooming effect (i.e. overestimation of lit area) due to the coarse spatial resolution, lack of multispectral information, a late overpass time after peak nighttime illumination, and a lack of ground-based calibration. Overcoming these shortcomings was a key goal for this client.

Simulated NITESat imagery from the same region

Modular Thinking, Agile Approach

Orbital Transports was selected as the prime systems integrator as we could support all aspects of the client’s mission from concept to completion. Our team determined that the mission payload could be hosted on a low-cost modular nanosatellite bus, providing standard command and control, communications, power, and ADCS for the mission. Our modular approach saved the client money and time.

Our engineers designed the imaging system for the mission payload to collect night time imagery of Earth while the nanosatellite is in eclipse. We ensured the imaging system is sensitive enough to detect dim light sources and has enough dynamic range to prevent saturation from all but the very brightest of city centers. We selected hardware that provides sufficiently high ground resolution to distinguish features such as major roads, commercial centers, and residential neighborhoods. We chose an RGB sensor that provides multispectral data, allowing identification of common sources of artificial lighting. Through the resources of our partner network, key capabilities were tested and validated on high altitude balloon missions launched at night.

Our team identified a flight opportunity to launch the nanosatellite from the International Space Station. The ISS orbit allows for varied overpass times at night during periods of peak illumination (astronomical twilight to 10pm). We optimized the mission by using daytime overpasses to transmit image data to the client’s ground station.

Mission Realized, Back to Business

Initially, the client was contemplating only the technical aspects of the mission. With the guidance of Orbital Transports, they were able to move forward on a low-cost, time-sensitive launch opportunity, and consider the legal and financial aspects, while lowering their risk. Now they are able to focus on studying the effects of light pollution—while Orbital Transports takes care of the space mission.

Let Orbital Transports assemble the pieces that fit best for your mission.

Contact us today for a mission assessment.

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