According to Eddie Adcock of the Advanced Sensors and Optical Measuring Branch, "This technology would improve the capability of NASA to achieve...the Agency's Vision to explore the universe and to search for life."

Photo by Jeff Caplan

Lassos in Space
Giant Slings Seek to Capture, Launch Spacecraft

Editor’s note: This is the sixth in a series of articles about small, high-tech, high-risk companies that have partnered with NASA through the Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) programs. Each one is different — different sizes, different locations, different technologies — yet all have become successful and are considered to be “Hallmarks of Success.”

By SHERI BEAM
Langley Research Center

TETHERS UNLIMITED INC.

Roping cattle takes skill and finesse, but imagine trying to lasso a satellite in space. Now, imagine flinging the satellite up to a higher orbit to actually launch it!

That’s what a small business in Bothell, Wash., is planning to do.
The researchers and engineers at Tethers Unlimited Inc.—TUI—are not cowboys, but they are developing unique lassos. Their “lassos” are new systems that will be used to capture and launch spacecraft.

The TUI tether is a long string or wire deployed in space from a spacecraft. These tethers can be used in different ways to move satellites or spacecraft in space.

The “lasso” concept is similar to a giant sling that would rotate as it orbits the Earth. The craft, ballast and tether increase orbital momentum and energy for boosting the payload to a higher orbit.

“It could swing down, pick up a spacecraft in low orbit and carry it up and toss it into a higher orbit,” said Rob Hoyt, TUI president.

Hoyt’s interest in space tethers began while he was in graduate school. Not long after graduating, he formed TUI with another tethers researcher. Very early on, the firm worked on a NASA project through a Small Business Innovation Research (SBIR) contract from Marshall Space Flight Center.

During that time, the company developed the “Hoytether,” named for Hoyt. With its multiple, interconnected lines, the Hoytether resembles a huge fishnet stocking. Its special netlike design actually provides the long-duration strength that’s needed while in orbit. Today, TUI is collaborating with the Air Force Research Laboratory to refine the Hoytether.

A few years after developing the Hoytether, Marshall funded TUI to continue its work on developing other tethers. The company then created the “Terminator Tether,” a cost-effective method for removing space debris after missions have been completed.

The Terminator Tether would be attached to a satellite before it is launched. When the mission is completed, the tether would deploy below the spacecraft. As the tether drags against the Earth’s magnetic field, it would lower the orbit of the craft, until it hits the upper atmosphere and burns up.

Using the Terminator Tether would have advantages over other methods for removing orbital debris. “It can deorbit the spacecraft with a much lower mass requirement than a rocket, and the system is basically self-powered,” Hoyt said.

Through another SBIR contract, TUI is partnering with Langley Research Center on a technology known as “SensorLine, which will enable spacecraft to deploy distributed arrays of microsensors on planet surfaces.

“This small business uses a truly innovative approach in solving a classical sensor deployment dilemma [by] providing a method to position a large array of sensors in hostile environments, with minimal impact on the weight and volume budget,” said Eddie Adcock of Langley’s Advanced Sensors and Optical Measuring Branch.

The microsensors would be able to perform a variety of experiments, such as taking measurements of temperatures, chemicals and other important data, usually done by more-expensive robots.

Sensorline could enable hazardous materials response teams to remotely place chemical sensors in contaminated areas, or provide troops with a safe and secure way to set up an array of sensors to warn of chemical weapons or other threats.

Adcock thinks the technology could undoubtedly have a major impact on various programs at NASA. “This technology would improve the capability of NASA to achieve many aspect of the Agency’s mission; specifically, the Agency’s vision to explore the universe and to search for life,” Adcock said. “The pending successes of this project ... could improve the current state of deployable sensors for a variety of applications.”

Through the In-Space Propulsion Technology Program, NASA is funding TUI to produce key technologies for a Momentum-Exchange/Electrodynamic Reboost tether system, called MXER (“mixer”). MXER will deploy a 100-kilometer cable in orbit around the Earth.

Hoyt says MXER will be like a railroad in space. The concept uses a high-strength, rotating, momentum-exchange tether that catchs payload and tosses it to a higher orbit, resulting in additional orbital energy for the payload.

“Essentially, it serves as a reusable, in-space, upper-stage and could handle missions to different destinations,” Hoyt said. “It’s a way of boosting multiple payloads from low-Earth orbit up to geo-stationery orbit, or to the Moon, or possibly even to Mars without using any propellant.”
TUI’s greatest obstacle to tether development is flight testing.

Most all of TUI’s potential customers want to see the tethers tested in a space environment. They were scheduled to test an experiment abroad a NASA shuttle mission, which has been postponed.

In the near term, TUI is using microgravity test environments to prove that its systems are reliable and can be operated successfully.

The firm is also conducting some very low-cost nano-satellite experiments.

TUI has teamed with Stanford University on a Small Business Technology Transfer (STTR) award from Marshall. With this contract, the team is developing a flight experiment, called the Multi-Application Survivable Tether, or MAST. MAST will deploy three mini-cube satellites along a tether to study how well the tether propulsion technologies will hold up in space.

A significant challenge or TUI is developing a new, different and unconventional technology. Although it has a niche market, the company knows what it takes to survive and be successful. Besides finding multiple customers for its technologies, Hoyt says, “You need to look for other markets for your technology or your skills that may not be entirely obvious.”

After realizing that it analyzes and simulates many strange and complex space objects, TUI formed a new division, called ScienceOps. Through ScienceOps, they provide scientific computing services to commercial companies.

Today, there aren’t any hard and fast requirements for commercial organizations to dispose of their spacecraft at the end of a mission, but the space debris issue continues to worsen. With more than 8,000 satellites and other large objects orbiting the Earth, and with more being launched, TUI is positioning itself to be ready with timely, low-cost solutions for lassoing satellites.

Sheri Beam is in charge of marketing and media relations for Langley’s Small Business Partnership Team.