3 CubeSats flying with OA-9 Cygnus spacecraft
WALLOPS ISLAND, Va. — Monday’s launch of Orbital ATK’s OA-9 Cygnus resupply mission to the International Space Station carried with it supplies and science experiments. Also riding with the cargo freighter are 15 CubeSats to be deployed by the outpost’s astronauts. These micro-satellites include a trio designed to greatly-enhance different areas of Earth observation.
The principal investigators for the three missions spoke about their briefcase-sized spacecraft at a “What’s On Board” pre-launch briefing at NASA’s Wallops Flight Facility Visitor Center auditorium on May 20, 2018.
The Temporal Experiment for Storms and Tropical Systems – Demonstration (TEMPEST-D), is a CubeSat developed at Colorado State University in Fort Collins, Colorado. It is designed to use radiometers to measure clouds and the precipitation processes within them. If its technologies are successful and eventually deployed in a satellite constellation, they could observe the origin of precipitation, and precipitation cycles on a global scale.
“We have to prove that this works, and after that we are going for a constellation,” V. Chandrasekar, TEMPEST-D’s primary investigator, told Spaceflight Insider. “But it is a stepped process. We have to show that it can work for 90 days.”
Chandrasekar said there are a lot of things the team needs to communicate and demonstrate such as orbital maneuvers.
“The thing about CubeSats is that they have no propulsion,” Chandrasekar said. “So just by tilting we have to do orbital maneuvering for the observations.”
The TEMPEST-D CubeSat’s attitude control is accomplished through the combination of reaction wheels and torque rods. Chandrasekar said that attitude control must be ultra-precise.
“We have to show that we can do that,” Chandrasekar said. “Then, because it is all radiometers, we have to show a very high level of precision of measurement, and show that all the smaller cheaper things we have developed are as good as the big boys. If we can do those three things, then we are good to go for the constellation.”
A successful demonstration of the TEMPEST-D technologies could lead to significant gains in the understanding of storms and important improvements in weather forecasting.
Radar in a CubeSat (RainCube) is designed to demonstrate the feasibility of a radar payload in a CubeSat platform. It is expected to use radar to measure rain and snowfall, and hopefully improve the capability on-orbit to validate climate and weather models using cost-efficient, quick-turnaround technologies.
One of these technologies is a compact—almost invisible—radar antenna deployment mechanism. It deploys almost like an umbrella, in stages, emerging from its hidden tubular orifice at one end of the CubeSat, very slowly, in its folded or retracted position, until the folded “ribs” of the umbrella are released from the orifice and spring the rest of the “umbrella” to the fully open position.
“It is a parabolic antenna about half a meter in size that is stored in a canister,” said Eva Peral, RainCube’s principal investigator at NASA’s Jet Propulsion Laboratory in Pasadena, California. “The ribs are spring-loaded, and they open up to become a parabolic reflector. This system can be used not only for radar, but can be used to improve the speed of many other communications in space.”
RainCube antenna deployment. Video courtesy of NASA
CubeRRT, pronounced Kew-bert, stands for the Cubesat Radiometer Radio Frequency Interference Technology. This satellite is designed to test new ways for future radiometer instruments to overcome the ever-increasing amount of radio frequency interference that satellites encounter while attempting to collect data. Microwave radiometers, which gather meteorological, climate, and soil moisture data, are encountering greater challenges in collecting their data due to radio frequency interference.
“As demand for the spectrum gets higher and higher it gets harder and harder to do these important scientific measurements,” said Joel Johnson, principal investigator of CubeRRT at the Ohio State University in Columbus, Ohio. “CubeRRT is all about attaching a new kind of processor to a microwave radiometer so that it can still continue to monitor and measure the natural thermal emissions, even in the presence of other signals coming from Earth that are man-made. We built a new processor, a very capable processor, and this will be the first time that processor has ever been used in space. The goal of CubeRRT is to demonstrate the success of that processor so that it can be used in future radiometer missions.”
What the CubeSat designs share in common is the original intent of all CubeSats—to make technologies for space smaller and cheaper, and to make space-bound research more accessible to more researchers at a lower cost.
The three CubeSats launched inside Orbital ATK’s OA-9 Cygnus spacecraft atop the company’s Antares rocket at 4:44 a.m. EDT (08:44 GMT) May 21, 2018. The resupply vehicle, named S.S. J.R. Thompson, is scheduled to reach the ISS in the early-morning hours of May 24. Once it rendezvous with the outpost, the Expedition 55 crew is expected to use the station’s robotic Canadarm2 to grab the spacecraft. Ground teams are then expected to remotely command the arm to berth the freighter on the Earth-facing port of the Unity module.
These three CubeSats and the 12 others are currently packed inside a NanoRacks deployer inside Cygnus. Once the spacecraft rendezvous with and is berthed to the ISS, the deployer is expected to be moved into the Japanese Kibo module by an astronaut. They will place it on a slide table to be transferred via the equipment airlock to the vacuum of space where the Japanese robotic arm will move it into a position for deployment. Exactly when this will occur is not known.
Video courtesy of NASA
Michael Cole is a life-long space flight enthusiast and author of some 36 educational books on space flight and astronomy for Enslow Publishers. He lives in Findlay, Ohio, not far from Neil Armstrong’s birthplace of Wapakoneta. His interest in space, and his background in journalism and public relations suit him for his focus on research and development activities at NASA Glenn Research Center, and its Plum Brook Station testing facility, both in northeastern Ohio. Cole reached out to SpaceFlight Insider and asked to join SFI as the first member of the organization’s “Team Glenn.”