The Kármán Line — 100 km or 62 miles above sea level — is where space arbitrarily starts. And through Project SpaceShot, the Stanford Space Initiative (SSI) plans to get there by December 2021 with a somewhat unusual rocket, nicknamed a “rockoon.”
The project, housed under both the Rockets and Balloons Teams at SSI, plans to have a zero-pressure high-altitude balloon carry a rocket 25 km up into the atmosphere. The spin-stabilized rocket will then launch through the balloon to complete the journey to 100 km, Project SpaceShot Co-Lead Ahmed Abdalla ’22 explained.
Abdalla had actually first heard of the idea at his Admit Weekend in June 2018, and decided to join SSI because of its originality.
“I thought either these people are just completely insane and they don’t know what they’re doing, or they’re going to do something super exciting,” Abdalla said.
In 2017, Berkeley’s Space Enterprise announced Project Karman, their attempt to pass the Kármán Line, and challenged peer institutions to join the collegiate space race. Universities around the nation had been attempting the feat for years, but Berkeley’s challenge prompted SSI to begin their attempt.
The University of Southern California’s Rocket Propulsion Laboratory (USCRPL) announced their victory on May 22, 2019 with 90% certainty. Their rocket, Traveler IV, was officially the first student-designed and student-built rocket to cross into space.
The 13-foot, 310 pound rocket is designed more traditionally than Project SpaceShot’s, using fins for stabilization and not utilizing a balloon.
“A lot of people have focused on the ‘bigger is better mentality,’” Abdalla said. “You know, a bigger rocket, super intense fuels and ‘muscle nearly all the way up there.’ SpaceShot has prided itself on trying to take a very ingenuitive approach that really shakes up what people expect from a suborbital launch system.”
Abdalla explained that the prospect of a space race as a motivation for the project is second to the fact that it is an interesting engineering challenge.
SSI Balloons Team Co-Lead Aditeya Shukla ’22 congratulates USCRPL for their successful launch but also feels that SSI is still in a space race of sorts.
“Fortunately for us, nobody has sent a rocket to space from a balloon [to this scale], so we’re still in the more unique territory,” Shukla said.
In space, balloons are normally used to fill the gap in the atmosphere that is too high for drones to reach but too low for satellites to orbit in order to obtain meteorological data or use cameras to monitor events like forest fires.
The idea to use a high-altitude balloon as a high launchpad for a rocket was born from SSI’s storied experience with balloons; they broke the world record for the longest high-altitude flight with a latex balloon in 2016 and has since broken their own record again.
“Since SSI is such a tight-knit community, the Balloons members were really interested in [Project SpaceShot],” Shukla said. “It was the balloons guys shooting up the idea that ‘what if we launched the rocket from a much higher altitude so that we have less drag and we can actually go to space?’”
Designed in 1957 during the Space Race between the U.S. and the USSR, NASA’s Project Far Side attempted a similar approach to getting into space. A rocket carrying scientific equipment was launched off a 200-foot carrier balloon. The rocket’s maximum altitude reached 6,440 km.
In the context of SSI, the atmospheric implications of launching a rocket from 25 km are a double-edged sword. Although the lower air pressure reduces drag, allowing the rocket to go farther, fins, which are normally used to stabilize rockets, are no longer sufficient.
“Usually you can use the fins as a way to counter the force of gravity trying to take you down by using aerodynamic forces to say, ‘Actually, I prefer the rocket to continue pointing this way,’” Abdalla said. “And as long as the rocket points up, the motors will be pushing in whatever direction up is. But you can’t do that at 25 km up.”
Using the rocket’s own momentum to stabilize it through spinning is another way to get the rocket pointed in the right direction.
“It’s going to be spin-stabilized, like a bullet, where it’s going to spin really fast and then hopefully go out straight,” SSI Rockets Team Co-Lead Maya Harris ’22 said. “And so it’s a really complicated project.”
The idea of spin stabilization did not come about until this past year. Before then, the plan was to use a three-balloon system, and SSI had yet to figure out a stabilization technique.
Once the spin stabilization technology was agreed upon, Abdalla’s task was to design a system that would allow the rocket to spin as fast as was needed to maintain stability; the fastest speed they reached was 2,700 revolutions per minute. He is proud of the progress he has seen with ground launches that were completed before campus closed due to COVID-19.
Next year, because of the uncertainty surrounding lab accessibility and the lack of ability to conduct launches, the team will use simulations to make progress on their goals.
This is something that SSI actually has experience with, Shukla said; some members have worked with research labs and companies like SpaceX, who have done similar simulations. Members modified Open Rocket, a program that allows users to design their own rocket, to better fit the design of Project SpaceShot, renaming it Open Rockoon.
“Normally, Open Rocket is open-source software where you can design any rocket and it’ll tell you all the details ranging from center of mass and center of gravity to how it will do with certain atmospheres,” Shukla said. “But Open Rockoon incorporates the balloon aspect of it and the spin aspect of it, so we can do much finer simulations that way.”
The code, CAD, avionics, onboard electronics and any other aspect of Project SpaceShot that a person would need to replicate the rockoon is open-source.
“What I think is really exciting for me about SpaceShot is the idea that we designed everything so if you wanted to send something to space with your high school or with your college rocketry team, you could really easily just do [so] on your own,” Abdalla said.
This openness aligns with the club’s mission to teach about space.
“SSI’s model has always been to give resources and knowledge to anybody who needs it, irrespective of whether they’re part of the organization,” Shukla said. “So every other project is also as open-source as SpaceShot.”
And so, in December of 2021, SSI hopes to cross into space, but the project itself means more than crossing an arbitrarily-defined line.
“Astrophysics and astronomy has always been such a big part of my life,” Adballa said, “and so actually being able to achieve the goal of getting there would be fantastic. But what we’ve done so far and all the progress that we’ve made is already so rewarding.”
Contact Alexandra Rozmarin at alexroz918 ‘at’ gmail.com.