Purdue Space Program



Competition Overview

Every year, SEDS USA and SSPI (Space and Satellite Professionals International) team up to host an international satellite design competition. Purdue SEDS has won twice in a row, and just placed third in the 2018 competition. This team was co-led by Tyler Mason (mason67@purdue.edu) and Brian Campana (bcampana@purdue.edu).


2018 System Summary

As space opens to new opportunities, the idea of a new multipurpose spacecraft has drawn the attention of governments and private space agencies. These entities desire a multifunctional spacecraft that could act as a workhorse in and around Low Earth Orbit (LEO). This conceptual spacecraft has been referred to as a “tug” due to a functional similarity to tugboats used at sea. The role of a space tug would be vital to this opening of space as a commercial frontier. There are several capabilities that would be incredibly beneficial to governments, private space organizations, and the commercial sector. These include the relocation of spacecraft, clearing of space debris, provision of maintenance to space stations, and material transport. A tug with this functionality would save time and money for all involved, and in most cases, these missions would be operated from the ground, without risk to human life.

The Purdue SEDS SSPI team designed a system called the Sisyphus Tug-Station System (STSS), named after the famous Greek myth of Sisyphus, a King whose punishment was to push a rock up a hill for eternity. This system was designed with flexibility in mind, acting in regimes from an orbital janitor to a resupply system. This is accomplished by separating the system into three major components - the STSS Hub, STSS Tug, and the STSS modules.

A model of the STSS Hub.

A model of the STSS Hub.

The STSS Hub serves as a fuel depot and general rendez-vous for the STSS Tug and STSS Modules. The first system is placed in an 800 km altitude orbit, as that is where some of the highest concentrations of orbital debris are found. It is capable of storing enough Argon to fill the tanks on-board the STSS Tug twenty times. There are two berthing modules at either end to support docking with the STSS Tug and resupply capsules sent from Earth. The two Canadarm-esque arms coming off of the fuselage of the STSS Hub are there to grab onto STSS Modules, such as the claw system or any future expansions to the system, such as a human transport module.

A model of the STSS tug.

A model of the STSS tug.

The STSS Tug  was designed to be capable of delivering up to 3000 kg to the proposed Lunar Orbital Platform-Gateway (LOP-G), previously called the Deep Space Gateway (DSG), while also maintaining the flexibility to deorbit debris or move debris into a dead orbit. The STSS Tug is also capable of servicing different inclinations, with the plot below demonstrating the maximum mass at any originating radius value and inclination value to deorbit.