The helicopter testbed has been used to demonstrate the effectiveness of algorithms Chung and his students, Dan Morgan and Saptarshi Bandyopadhyay, have developed for implementing swarms consisting of hundreds to thousands of very small spacecraft – each about the size of an iPhone. Using the swarms for a mission instead of one large craft can reduce costs. The mission’s launching and operating costs would be less, and losing one small craft in a swarm would be less expensive than losing and/or replacing a large craft, plus the mission would not be interrupted.
“Even though the motion of the helicopters is very different from the motion of the spacecraft, this testbed still gives us a way of verifying our algorithms in a real-world setting,” Morgan explained. “This gives us information that we cannot obtain from computer simulations.
“In addition to testing our algorithms, the testbed also allows us to demonstrate potential uses of the swarms of spacecraft. One of the main advantages of swarms is the ability to deal with individual spacecraft malfunctions. This idea is shown in the video. As each helicopter is removed, the remaining helicopters adjust their positions to maintain the formation, which is a circle in this case. Additionally, these malfunctioning spacecraft can be replaced if necessary. This idea is demonstrating in the second half of the video as helicopters are added to the formation.”
Swarms of spacecraft provide new challenges that have not existed in previous space missions. First, the large number of spacecraft working together in a small area greatly increases the probability that some will collide. Additionally, the spacecraft must be extremely small in order for the mission to be more cost effective than flying a single spacecraft. The small size of the spacecraft results in limited computing and communication capabilities. One particular mission in which formation flying excels is space telescopes, Morgan said. Launching a large telescope can be either very expensive or impossible. However, several smaller telescopes can be launched and placed close together in order to imitate a larger telescope.