SUDBURY — A hush fell as a dozen Boston University students, clustered atop a sandy hill on a recent Sunday morning, trained their attention on a 14-foot-tall test stand several hundred feet away.
“Autosequence starts in 3, 2, 1,” Jeremy Pedro, a sophomore, counted down. On cue, a jet of flame erupted from the rocket motor mounted within the stand. For 20 seconds, a roar filled the former sand quarry and black smoke billowed.
There was no liftoff that day; the motor, called Mark IIB, was anchored to the ground by 10,000 pounds of concrete. But this was no classroom demonstration, either. It was one in a series of tests that the ambitious team of undergraduates has scheduled over the past three years in the hope of setting a few world records this summer.
If they are successful, experts say, they will be the first group of amateurs to build and launch a particular type of rocket — a 30-foot hybrid fueled by a combination of liquid and solid fuel — all the way into space.
The feat would elevate BU, a school that hasn’t been a typical leader in aerospace engineering, to the cutting edge of amateur rocketry. While most people know of professional rocket scientists in industry or government, there is a vibrant and increasingly ambitious amateur rocketry community that includes teams at universities across the country as well as hobbyists.
Getting hybrid rockets into space, however, has been a particular challenge for both amateurs and professionals.
“It’s been a holy grail nobody has been able to crack,” said Thomas Atchison, chairman of the Mavericks Civilian Space Foundation, a nonprofit in California that runs education programs and provides support for amateur rocketry. “These guys, I think, are going to do it — which is pretty remarkable.”
It’s a big goal by any measure — the technology is complex, and the logistics and fund-raising are equally as daunting for a project of this scale. The actual rocket launch requires permits from the federal government, which the students say they are in the process of obtaining.
On top of it all is the difficulty of coordinating a team of undergraduates to collaborate on a multiyear effort that can add up to as much as 60 or 70 hours of extracurricular work each week.
There are about 40 team members in the student-run BU Rocket Propulsion Group, with a core group of about 15 who put in the longest hours. At the Sunday launch, there was some talk about whether there would still be a Monday meeting of the rocket club even though people were in the midst of taking finals. The answer was unwavering: of course.
The faculty adviser for the team, Caleb Farny, is a lecturer at BU in mechanical engineering whose specialty is in instrumentation and measurement analysis, not rocket design. He’s always liked the rocket team, which formed in 2003, because it gave students a chance to apply principles they learned in the classroom by solving real engineering problems and building real rockets.
About three years ago, the team scaled up its ambitions, when Armor Harris, who had developed extensive experience with amateur rocketry in high school, made a bold proposal.
Harris, now a senior, proposed that over three years, the team would build successively more powerful rockets and motors, learning lessons that would culminate in a large hybrid rocket capable of reaching space.
“My personality and disposition is always kind of set up to do something nobody’s done before, so I came up with this goal to go to space,” said Harris, who plans to work at SpaceX, which designs and manufactures rockets and spacecraft, after graduation.
When Farny heard that the student club had decided to build a large hybrid rocket nicknamed Starscraper — using a technology that had enormous promise but had been largely neglected by industry because it was finicky — he initially discouraged them.
He said he told Harris “this was way too ambitious. It can’t be done for a number of reasons, and one of them is money.”
The team budget for the year is $110,000 and a number of corporate sponsors — including GE Aviation and Raytheon — and BU support the effort. The team has about $40,000 left to raise and is currently running a Kickstarter fund-raising campaign .
When the time comes, just getting their rocket out of the lab won’t be simple. In order to get Starscraper out of the basement laboratory where they have been building it, the team will have to angle it out a window and push it on a 20-foot-long ramp built by one of the team members. They will load it on to a custom-built trailer to drive it all the way to the Black Rock Desert in Nevada for an attempt at history in July.
The stats are impressive: Starscraper’s motor will burn for 60 seconds and reach 4.7 times the speed of sound, and the rocket will soar to a height of at least 62 miles. If successful, the rocket would re-enter Earth’s atmosphere, deploy parachutes, and be recovered by the team.
The hybrid rocket is powered by a combination of fuels: a solid fuel that is a type of rubber and a liquid fuel, nitrous oxide. The team likes to joke that its rockets are fueled by tire rubber and laughing gas.
Liquid fuel rockets are high-performance and expensive, like the ones NASA sends to space. Solid fuel rockets have lots of thrust, but lots of vibration.
The hybrid rocket seemed to the BU students like a technology that could have many practical uses. It offered higher performance and control than a solid fuel rocket and a smoother ride that could potentially launch a sensitive scientific instrument into space.
“We don’t encourage people to do these types of things unless they know what they’re doing, and this team is incredible,” Atchison said of the BU students.
Even with great preparation and testing, success is not certain. Every test is an opportunity to learn and improve.
After the Sunday test, the diagnostics began. Was the smoke a sign that a new nozzle design they were testing had ruptured or just a sign the wind had changed direction? The team clambered down the hill to begin their inspection.
“If it were 100 percent certain it would work, that wouldn’t be that interesting,” Harris said.