University of Southern California (USC) students soared above an international altitude record, launching an amateur rocket 470,000 feet into space.
The Aftershock II spacecraft has now broken a twenty-year-old record set by hobbyists from the Civilian Space eXploration Team (CSXT), who in 2004 managed to launch their rocket to an altitude of 100,000 meters.
But USC’s Aftershock II also reached hypersonic speeds: It reached a maximum speed of 1,800 meters per second at Mach 5.5, or more than five times the speed of sound.
Now their deliberately lightweight rocket, weighing about 330 pounds, has made history as the first launch by individuals outside of government or private industry to ever take off so far beyond Earth’s atmosphere..
Student Ryan Kraemer, who worked as an executive engineer on the project, said Aftershock II featured “the most powerful solid propellant engine ever fired by students and the most powerful composite housing engine made by amateurs.”
The 4-meter-high craft with a diameter of 23.5 cm was powered by a custom-made, ‘ammonium perchlorate composite’ solid chemical propellant, invented by students themselves.
“Using a formula developed by students at the club,” according to the USC Rocket Propulsion Lab (USCRPL), “each propellant bead is created by USCRPL from raw chemicals, setting the club apart from many other collegiate rocket teams. ‘
Fittingly, USC’s Aftershock II and CSXT’s previous record holder were both launched from the same spot: the remote Black Rock Desert, 100 miles north of Reno, Nevada.
The University of Southern California’s student-run Rocket Propulsion Lab (USCRPL) designed and built the new record-breaking rocket, Aftershock II. Above, the nose cone of the student rocket, photographed in space during their successful, historic space launch on October 20, 2024
The student rocket broke a 20-year record set by hobbyists from the Civilian Space eXploration Team (CSXT) – which launched a 350,000-foot rocket in 2004, surpassing the official mark into space. Above is a video from the USC rocket that broke CSXT’s record
USCRPL students last made history in 2019, when the club became the first student group to fire a rocket above the Kármán Line: the internationally recognized legal boundary separating Earth’s atmosphere from space, 62 miles above sea level.
Aftershock II climbed another 27 miles into space, for a total of 87 miles.
‘This special group of students shows how you can imagine it, what you can do in the lab and how you can make it reality.’ Yannis Yortsos, dean of USC’s Los Angeles-based Viterbi School of Engineering, said a university statement.
“It is exciting to see how they have now not only broken their previous global student record of reaching the Kármán Line,” Yortsos added, “but also the record of any amateur team in history.”
The rocket’s ability to endure the heat and friction of its Mach 5.5 hypersonic ascent was made possible by the club’s new thermal protection design – which includes a new paint job and titanium coating for the rocket’s fins.
“The titanium not only prevented fraying, but actually turned blue from the intense heat during flight due to anodization,” said Kraemer, who studies mechanical engineering when not active at USCRPL.
The hot anodizing reaction where the oxygen gas rubs against these fins, he says, “really demonstrates the extreme conditions that our rocket has successfully endured.”
“Thermal protection at hypersonic speeds is a major industry-level challenge,” the student added, “and the protective paint system we developed performed perfectly, allowing the rocket to return largely intact.
Fittingly, USC’s Aftershock II and CSXT’s previous record holder were both launched from the arid and remote Black Rock Desert, 100 miles north of Reno, Nevada. Above, students from the USC Rocket Propulsion Laboratory club watch as their Aftershock II blasts off on October 20, 2024
USCRPL’s custom-built electronic suite, dubbed the ‘High Altitude Module for Sensing, Telemetry, and Electronic Recovery’ or ‘HAMSTER’ system (above), included a radio-based transponder to measure altitude and five circuit boards of computing power
Earlier versions of the USCRPL missile fins had edges composed of bare carbon.
The latest history of the club that makes a rocket, Traveler IV launched in 2019, had returned from outside the Kármán line with the paint on the rocket “completely burned off” and “excessive ‘heat damage’ to the leading edges of the fin.”
“To exceed the standard we set for ourselves with Traveler IV, we had to solve many technical and operational challenges,” said Kraemer.
For example, to power thrust beyond Earth’s atmosphere, Aftershock II’s solid-fuel engine ultimately required nearly 200 pounds of propellant consisting primarily of controlled-release propellant pellets, known in the industry as the BATES type.
The team also had to design and program a unique avionics system, both to guide the craft and to record flight data that would be used in their official document on the historic Aftershock II launchpublished on November 14.
USCRPL’s custom avionics suite, dubbed the “High Altitude Module for Sensing, Telemetry, and Electronic Recovery” or “HAMSTER” system, included a radio-based transponder to measure altitude and five circuit boards of computing power.
HAMSTER’s Integrator Board integrated live sensor data from the rocket’s magnetometer, gyroscope and accelerometer to locate the rocket’s highest point, or apogee.
And the ‘Lightspeed Rangefinder Transponder’ measured the distance to multiple points on the ground to calculate the spacecraft’s radio-based, radar-like method known as trilateration.