How a $10K student built cubesat can help clean space junk

SBUDNIC: A solution with a shoestring budget

It was one of the smallest and cheapest satellites ever sent to space, costing only about $10,000 and measuring 10 by 10 by 10 centimeters. Built using readily available materials like 48 Energizer AA batteries, SBUDNIC's journey started on Elon Musk's SpaceX rocket last May as part of the Transporter 5 ridesharing mission. Brown alumnus Marco Cross, faculty member Rick Fleeter, and an academically diverse team of undergraduates worked diligently to address the growing problem of space junk.

A key feature of SBUDNIC is a plastic drag sail made from Kapton polyimide. Unfurling like an umbrella at about 520 kilometers, it allowed the satellite to descend to Earth faster than anticipated.

Selia Jindal, a recent Brown graduate and project lead, explained that the aim was to showcase inexpensive ways of deorbiting space debris. She stated, “This showed that we can do that...there are significant plans we can put in place to combat the space junk problem that is cost-effective.”

The main objective of SBUDNIC was to demonstrate that space debris can be reduced by using passive deorbiting devices that do not require any propulsion or complex mechanisms. The students chose Kapton polyimide, a material commonly used in spacecraft insulation, to make a drag sail that deployed like an umbrella once the satellite reached its orbit at about 520 kilometers above the Earth.

Impact on space debris reduction

The implications of this successful proof of concept could be substantial in the fight against space debris. 

Dheraj Ganjikunta, a Brown graduate of 2022 and the lead program manager of SBUDNIC, contrasted the project with other more expensive and complex solutions for space junk, such as space tow trucks or nets. Praising the SBUDNIC for its low-cost and simple approach to tackling the problem of space junk, he said that SBUDNIC was amazing because it used a simple $30 drag device that could be attached to satellites and shorten their orbital lifespan.

NASA reports that more than 27,000 pieces of orbital debris or space junk are being monitored by the global Space Surveillance Network of the Department of Defense. The worst-case scenario is a satellite explosion setting off a chain reaction, hitting other satellites in the same orbit. Marco Cross, SBUDNIC’s chief engineer, warned, “We need to be prepared.”

Overwhelming success

Most satellites remain in orbit for an average of 25 years after serving their purpose. In line with the Federal Communications Commission's new 5-year rule for deorbiting satellites, SBUDNIC demonstrated a swift success.

SBUDNIC, a small cube satellite designed and built by Brown University students to demonstrate a practical, low-cost method to cut down on space debris reentered Earth’s atmosphere about five years ahead of schedule. @brownengin https://t.co/eJgMQzUaIq

— Brown University (@BrownUniversity) August 18, 2023

SBUDNIC's drop was visibly exponential, burning up in the atmosphere from the heat generated from re-entry. While other similarly-sized satellites remained at higher altitudes, SBUDNIC's last known position was recorded at 146 kilometers.

A solar activity might have contributed to SBUDNIC's rapid descent, but the exact influence is still under study.

An unusual learning experience at Brown

Created on Brown's campus and developed as part of the Design of Space Systems course, SBUDNIC was built in a year by about 40 students from diverse fields such as engineering, economics, and sculpture.

Rick Fleeter, an adjunct associate professor in Brown's School of Engineering, reflected on the project, “In terms of depth of learning in this project, this is the kind of experience that I think students come to Brown for.”

As of mid-August, all other comparison satellites are still in orbit, a testament to SBUDNIC’s remarkable efficiency and design. The success of this project represents not just an academic achievement but a significant step forward in space technology, offering a low-cost and practical solution to a pressing global challenge.