By Bob Granath,
NASA's John F. Kennedy Space Center
As NASA plans for future spaceflight programs to low-Earth orbit and beyond, teams of engineers at the Kennedy Space Center in Florida are gaining flight systems experience in designing and launching vehicle systems on a small scale. As part of Rocket University, the engineers are given an opportunity to work a fast-track project to develop skills in flight systems through the life cycle of a program.
Four teams of five to eight members from Kennedy are designing rockets complete with avionics, separation and recovery systems. Launch operations require coordination with federal agencies, just as they would with rockets launched in support of a NASA mission.
"Rocket University began in the summer of 2010," said Kevin Vega, assistant chief engineer for NASA's Commercial Crew Program (CCP). "As the Space Shuttle Program was coming to an end, we realized many of our engineers were working systems designed long ago. 'Rocket U' was developed to help civil service and some contractor engineers expand their skill set, flight systems engineering experience and learn to manage design programs."
Rocket University is designed to develop, refine and maintain flight engineering skills. The training program's goals include developing and testing new technologies and potential ground-breaking systems through projects involving small scale vehicles. The effort also provides a fresh perspective to engineers who then take this hands-on expertise back into large-scale NASA programs, providing for more experienced, multi-disciplined systems engineers.
NASA is currently working in partnership with the nation's aerospace industry in the Commercial Crew Program to develop space transportation systems to launch astronauts safely to the International Space Station. Also in the design stages are the Orion multi-purpose crew vehicle and the Space Launch System advanced, heavy-lift rocket to provide the capability for human exploration beyond low-Earth orbit.
Rocket University involves research and development in four platforms: rockets, unmanned aerial systems, weather balloons and the Neo liquid engine test bed.
"All these platforms have different training classes," said Vega, who also is the Rocket University rocketry lead. "The students are assigned projects based on the platform they are working. In these cases, it's done on a small scale with the full-scale project outline."
The scaled-down projects allow the efforts to be completed over a period of months rather than years, as a full-scale system would require.
On May 24, a team calling itself the "Space Coast Star Chasers" launched a single-stage rocket that was more than seven feet tall from Kennedy's Launch Pad 39A. The goal was to independently test its in-house deigned avionics systems and to verify that it performed as planned, along with additional objectives to validate the rocket's functional and structural integrity. This marks the team's second test flight and first from Kennedy.
"In developing a rocket, each team member has an area of responsibility such as chief engineer or avionics," Vega said. "While some of the design characteristics are pre-determined, the team has the responsibility to develop unique elements including how some of the vehicle's systems work and ensuring there are back-ups in place to complete a successful flight and recovery."
Like any NASA launch vehicle, coordination is required prior to launch. This includes involving organizations such as the NASA/Air Force Management Office, NASA Range Safety, NASA Safety and Mission Assurance and the Kennedy Launch Weather Office.
This kind of coordination sets the ground work for future customers interacting with the U.S. Air Force's 45th Space Wing command, as well as NASA Range and Safety officials to provide a streamlined process to launch more frequently at Kennedy. The teams also use predictive modeling processes for ascent and recovery including day before and day of weather forecasts from the 45th Space Wing Weather Office.
"In the design process, engineers learn to not only develop designs," Vega said, "but to also determine the coordination for a decision, the impact to other systems and overall risk for a particular change or approach. In the end, the engineers are accountable for their decisions.”
The rockets use commercial, off-the-shelf parts to develop a uniquely designed avionics system for high acceleration platforms. A microcontroller unit is programmed to autonomously command critical mission events with data gathered from an altimeter and an inertial navigation system including accelerometers, gyroscopes and magnetometers. The use of a wireless telemetry system allows for real-time downlink of data and uplink of commands.
Each of the rockets uses a solid propellant motor. This test was with about 300 pounds of thrust for launch and a drogue and main parachute system for safe recovery. The teams develop the avionics to measure velocity, position, acceleration and altitude, as well as a system to command deployment of the parachutes.
"The challenge for the team that recently launched a rocket was to ensure they could receive telemetry from the rocket during flight and to also send commands up to the vehicle while it was flying," said Susan Danley, chief engineer for the Star Chaser team. "In this case, the uplink command was to open a small door near the top of the rocket, which was simulated on this test flight."
On a future flight, the plan is to send up a command to have the door open, deploying an American flag that will be attached to the side of the rocket.
"Other instrumentation measured the rocket's performance at a predicted sub-sonic speed of Mach 0.59," said Danley who works in the Flight Structures branch of the NASA Engineering and Technology Directorate.
Mach is the speed of sound -- about 741 miles per hour at sea level.
"After the rocket motor fires for less than two seconds, the rocket coasts for about 14 seconds to its maximum altitude," said Danley. "The team designed the avionics systems to deploy the drogue parachute at apogee -- the highest altitude -- and main parachute at 700 feet up during descent. If that doesn't happen, a redundant system will deploy a back-up ordnance charge to deploy the parachute at 450 feet."
Vega explained that the other three teams are designing rockets with similar challenges.
In the final portion of the Rocket U program, the four teams will join forces and develop a three-stage launch vehicle capable of flying to an altitude of between 90,000 to 150,000 feet, carrying a payload with experiments.