NASA Approves Demonstration Flight for Circular DiskSats

NASA Approves Demonstration Flight for Circular DiskSats

NASA Approves Demonstration Flight for Circular DiskSats

SAN FRANCISCO – NASA approved a demonstration flight for DiskSat, the thin circular satellite designed by the Aerospace Corp.

Engineers from Aerospace Corp. are building four DiskSats and a DiskSat dispenser, which they plan to send to low Earth orbit by 2024 to validate the technology.

“People ask me, ‘Can you really fly that? Can you control it?’” said Richard Welle, DiskSat inventor and senior scientist in Aerospace’s Mission Systems Engineering division. Space news† “It’s a very bulky vehicle compared to other things that are traditionally flown. Can you do the heat management so you don’t melt by collecting all that solar energy?”

DiskSats with a diameter of one meter are 2.5 centimeters thick. With the large surface area for solar panels, DiskSats could deliver about 60 to 80 watts to on-board electronics. A DiskSat with a rigid solar panel provides an average power on board of 100 to 160 watts.

Much of the power will likely be used for propulsion. During the demonstration mission, Aerospace plans to fly DiskSats into very low Earth orbit.

A pair of DiskSats, deployed from a rocket at an altitude of about 500 kilometers, will maneuver to an orbit of 250 kilometers. With propulsion to combat resistance, mission planners plan to keep the DiskSats at that altitude for more than a week before moving them to higher orbit.

The second pair of DiskSats will fly into eccentric orbit with a perigee of less than 200 kilometers.

“The propulsion system has enough thrust to compensate for drag up to about 230 kilometers in a circular orbit,” Welle said. “But in an elliptical orbit, you can go lower, provided you have time at a higher altitude to do the drag makeup.”

In late April, Aerospace began the 18-month development campaign for the DiskSat demonstration mission. No launch vehicle has yet been identified.

At the Small Satellite Conference at Utah State University in August, Aerospace plans to showcase a DiskSat model.

“We’ll be happy to talk to anyone interested in driving a DiskSat,” Welle said. “We plan to develop a DiskSat standard, analogous to the cubesat standard. We will define the interface between the satellite and the launch vehicle with the idea that it can be used in rideshare operations.”

Aerospace engineers are developing a dispenser to release the circular spacecraft.

“In the long run, you might have flights with 20 DiskSats in a single dispenser,” Welle said. “We are developing a dispensing mechanism that will release them one at a time with a reasonable amount of time in between to ensure separation between adjacent disks in the stack.”

Welle sees significant advantages of circular DiskSats over Cubesats.

In terms of power, an eight kilogram DiskSat with a flip-out panel can easily deliver 100 watts of average power on board. To deliver the same power, a cubesat with fold-out panels would weigh about 30 kilograms, Welle said.

With higher power and lower mass than cubesats, DiskSats could use electric propulsion to drastically change their orbits. For example, a 10-kilogram DiskSat could move from a low Earth to a geosynchronous or even lunar orbit.

In addition, the two-inch bezel of a DiskSat would experience little atmospheric drag, which is why the miniature satellites could operate at low altitudes. There is a growing interest in very low orbits where sensors can collect high-resolution images of the Earth.

“Using DiskSats under 300 miles is easy,” says Welle. “That gives you a whole new orbital regime that isn’t overpopulated by other satellites.”

DiskSats are lightweight composite structures with hollow interiors. Components can be distributed throughout the internal volume or clustered in a central avionics space.

“There’s a lot of volume that’s scattered and easily accessible,” Welle said. “It greatly simplifies the production process.”

Additionally, DiskSats in low Earth orbit will likely soon enter Earth’s atmosphere once their missions end. Without attitude control, a DiskSat orbiting 600 kilometers will enter the atmosphere for about two and a half years.

“If the attitude control system fails, the satellite collapses,” Welle said. “That will increase the drag by an order of magnitude.”