They’re working to build it bigger and send it higher. Cal Poly Space Systems is one step closer to building a rocket that will reach space.
Space Systems has built five hybrid motor (HM) rockets during the past decade using liquid and solid fuels, according to club president and materials engineering senior Joe Vanherweg.
The first four were “test stand” engines that didn’t fly, but this past year’s rocket — the fifth — was the first to launch. And now the latest rocket, called HM6 or the “Lockheed Martin Rocket,” is far more advanced than any rocket Space Systems has ever built, Vanherweg said.
“The difference between HM5 and HM6 is that HM6 is about 15 times larger,” Vanherweg said. “It’s a lot bigger, a lot more power.”
Near the end of Spring 2012, aerospace company Lockheed Martin approached Space Systems with an interest in producing a hybrid rocket it could use to test small satellites. After that, Space Systems came up with a sounding rocket, which can be used to test different payloads for various organizations including Cal Poly’s CubeSat and PolySat projects.
Space Systems has a strategic plan to eventually build a vehicle that will enter space while carrying a 3U CubeSat (three CubeSats stacked together), Vanherweg said.
“We want to be able to launch that payload into space for testing,” Vanherweg said. “That would be a highest-level sounding rocket, and that’s the goal of our strategic plan.”
What’s in a rocket?
One of the benefits of the club’s decision to design hybrid rockets is in the fuel they use. A hybrid rocket uses both a solid fuel and a liquid oxidizer, which allows it to be much safer and less likely to explode, Vanherweg said.
“A hybrid has higher performance than a solid engine, but it’s not nearly as complicated as a liquid engine,” Vanherweg said.
The solid fuel in the club’s rocket will be made of hydroxyl-terminated polybutadiene, the plastic used to manufacture tires.
When the liquid oxidizer enters the chamber with the plastic, it turns into gel. The gel is then ignited and the exhaust gases push through the nozzle, creating thrust, fellow materials engineering senior Ross Gregoriev said.
But when creating rockets, money, not just innovation, can go a long way toward a project’s success.
Space Systems currently has a $35,000 budget for the HM6. It received $10,000 from Boeing Co. and approximately $5,000 from various aerospace industries. National Aerospace Supply Co. donated vacuum bagging materials, and Nextel Aerospace Defence and Security donated two rolls of carbon fiber cloth. Now Space Systems is waiting for funding from both the Lockheed Martin and Orbital Sciences corporations, which has caused a delay in rocket production.
From HM5 to HM6
Vanherweg has been working on hybrid rockets at Cal Poly, starting with Space Systems’ HM3 project, for several years. This past year’s rocket, the HM5, was Vanherweg’s senior project, in which he focused primarily on mechanical design, along with three other aerospace engineers, he said.
The difference between the HM5 and the HM6 is not only innovation but scale, Vanherweg said. While Space Systems’ past rockets have been capable of carrying 10 pounds of payload, the team is anticipating that HM6 will be able to carry up to 60 pounds, Vanherweg said.
The power of a rocket is measured by total impulse, or how much energy the rocket produces, Vanherweg said. The HM5 and HM6 will burn for the same amount of time: approximately 10 seconds. Yet the HM6 will produce a considerably greater amount of thrust, he said.
“HM5 produced 225 pounds of thrust,” Vanherweg said. “HM6 is designed to produce about 3,000 pounds of thrust.”
The HM6 is also designed to reach an altitude of 60,000 feet. This surpasses the last Space System’s launch, which reached an altitude of 25,000 feet (according to NASA, “Space” begins at an altitude of 264,000 feet).
Problems, propulsion and production
The HM6 brings a significant increase in challenges within rocket production, because of the substantial change in size and power, Vanherweg said.
First, no motor is commercially available for Space Systems to buy that is capable of going high enough with the amount of weight the HM6 will carry, he said.
But according to propulsions team leader, Steven Rieber, Space Systems faces difficulties in creating the rocket motor itself.
“We have to use different tools for a lot of our parts and we might have to (use Computer Numerical Control on) a bunch of things, so it will be a lot more challenging,” Rieber said.
Space Systems’ is also incorporating multiple disciplines on this project: Space Systems members will likely spend between five to 10 hours per week on HM6 production, with each discipline focusing on its role, Gregoriev said.
“We will have basic control systems done by the end of this quarter,” Gregoriev said.
To test the control systems, Space Systems will do a rocket launch using past rockets such as the HM5. This is necessary to ensure its reliability, because there have been problems with past launches, Gregoriev said.
Space Systems current focus is working on small-scale tests to make sure the design of the HM6 is correct, Vanherweg said. Next quarter, the team will begin building large components of the rocket once they’ve confirmed the design calculations, Vanherweg said.
The club estimates it will finish the project in March 2014, and launch around that time or possibly later, Vanherweg said. The team is expecting to launch from the Mojave Desert at Friends of Amateur Rocketry, a non-profit organization. It previously launched two rockets from this location, Vanherweg said.
Space Systems has used the launch stand equipment from Friends of Amateur Rocketry in the past. However, the team is negotiating with the Cal Poly mechanical engineering department to use a launch trailer built for a student’s senior project a few years ago, Vanherweg said.
No matter the specifics of the project, the HM6 is still a huge leap forward, Vanherweg said.
“It’s way bigger than anything we’ve ever done before,” Vanherweg said. “I guess that’s the best way to put it, it’s way cooler.”
Katie Tomayk0 contributed to this article.