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Starscraper

The Next Generation of Suborbital Rockets

Boston, MA, United States

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Starscraper is a 30 foot-long, 1,100 pound suborbital rocket that can carry 100 pounds of experiments 435,000 feet into space and return gently to earth. But beyond that, Starscraper is an educational breakthrough.  It’s a project that allows us to figure out how to do things never thought possible to do at the student level, which has important implications in all disciplines.

Our vision is to launch Starscraper on July 25, 2015. We believe that the Megafounder community can help us close the gap on support to realize this vision. Check out Update #4 for more information about how you can design a payload for the rocket that will be launched into space and brought back to Earth.

Schematic of Starscraper

Up close view of a Mk IV hot fire test. The Mk V's predecessor, the Mk IV is a subscale motor used on the Quasar launch vehicle.

Currently, NASA and a few commercial companies offer a fleet of suborbital rockets that launch about 100 times per year worldwide. They conduct research in physics, biology, space weather, astronomy, and microgravity research. However, they have two problems;

  • These solid fuel rockets subject their payloads to extreme conditions: more than 20 times the force of gravity in some cases with vibration more intense than a jackhammer. 
  • They are expensive and single use only; after launching their payload out of the atmosphere, the booster rockets are discarded. The cost of a NASA sounding rocket mission is on the order of about a million dollars per launch.

The extreme forces experienced by the experiments onboard limit the research that can be done by these flights. The problem is that the extreme launch environments are functions of the solid fuel rocket boosters used: they burn very quickly with a lot of thrust, generating intense acceleration.

A solution to this is to use rockets powered by liquid fuels – like the Saturn V from Apollo. But liquid rocket engines are expensive and would make an already expensive solid rocket propelled mission cost-prohibitive. 

Mk IV oxidizer tank after a cold flow test. Following the cold flow test, the tank reaches a temperature lower than -50 degrees Celcius.

Starscraper uses a relatively underdeveloped type of rocket technology called a hybrid motor. This motor (which you can learn more about on our website) uses a combination of solid fuel and liquid oxidizer which produces less thrust at a greater efficiency than a solid rocket. As a result, our rocket motor burns smoothly for a very long time. This means that our rocket places much less stress on our payloads, about what you would experience on a theme park ride. We do this by throttling back the motor as the rocket ascends to keep acceleration loads small.

With a long burning rocket, it is hard to keep it pointed where you want it. That means that we need a stabilization and control system just like the Space Shuttle or Saturn V. We have figured out how to do this with low-cost, off the shelf components that is good enough for what we need at a small fraction of the cost of traditional flight control systems.

It is also reusable. The entire rocket re-enters the Earth's atmosphere and lands using big parachutes for a soft touchdown. The rocket can then be re-fueled and re-launched for the next mission. Traditional "throw-away" rockets of this size are like throwing away something that costs as much as a house after each flight. With our reusable rocket, we are re-using something that costs as much as a car after each flight. 

We have partnered with two organizations called Magnitude.Io and Teton Aerospace that are dedicated to advancing math, science, engineering, and technology education around the world. Our first launch will carry 20 lbs (or 9 kg) of CanSats, satellites built to fit the approximate form factor of a soda can. These suborbital payloads can be built by anyone from high school students all the way up to sounding rocket scientific instruments. The idea is that it gives anyone a chance to work on real space-grade hardware, fly to space and analyze the data from launch and in-space operations.

  

The Mk IV on the test stand during a hot fire test. 

Yes. We are a team of passionate students at Boston University who have been working hundreds of man-hours per week for three years to make this possible. Interestingly, Boston University does not have any faculty members with backgrounds in rocket propulsion, so we have had to learn everything ourselves. As a result the program is entirely student run.

From the rocket engine to the flight computers to the trailer used to carry the rocket, everything we design and build is from scratch. 

Hyperion Rev. A - Data Acquisition and Fuel & Process Control Board 

Kronos - the primary flight computer on Starscraper. 

SolidWorks rendering of Atlas, the transporter and test stand for the Mk V motor.

 

Current progress on Atlas. 

Suppose you had two students: a theoretical learner and a hands on learner. You could go to the first one and he could derive you Bernoulli’s Law (the equation that governs flow in pipes) or you could go to the other student and they could build you a working high pressure fluid system. 

The second student is from the Boston University Rocket Propulsion Group. We take students that are restricted by traditional classroom learning and we put them in an applied environment and that is where the magic happens.

We have become very good at teaching through application. Undergrads are only at school for four years, we do not have time for them to take four years of classes and then start designing rocket parts. We need them to start designing rocket parts right away and we want to share what we come up with from an educational standpoint. 

Student installing electronics on the Mk IV motor 

Student working on parts for Atlas, the test stand for the Mk V. 

For the past three years, our goal has been to launch Starscraper for the first time in July 2015 in Nevada, and we are on schedule. We have built and test fired three sub-scale rocket motors, and are almost done testing every technology that we need for Starscraper (including flight testing the flight control system in January).

  • We are currently fabricating the first Starscraper and intend to start ground testing in February.
  • We have run a successful Kickstarter campaign, raising the funds that we need this year.
  • We are looking to continue the project on Megafounder and let their community join us.

Become a backer and you can be part of the team; gain exclusive behind the scenes access to the Starscraper mission. When we launch into space, you will be able to say that you were part of making it happen.

Front: ASTRo - Used to test our guidance systems. Rear: Mk IV - Launch Vehicle during the 2013-2014 Campaign. 

Mk V oxidizer tank being transported to the lab. The tank is 14 ft long, which is only less than half the length of the launch vehicle. 

How does the control system work?

We use small servo motors that turn small valves to inject liquid nitrous oxide into the nozzle, which creates supersonic shock waves in the expansion bell of the nozzle. This has the effect of changing the direction that the thrust is pointed. It is called Liquid Injection Thrust Vector Control. This is much lighter and cheaper than other methods of vectoring thrust, which either require heavy and expensive actuators or flexible bearing joints that can withstand extreme temperatures and require exotic materials.

What about the high loads during re-entry?

Our rocket bleeds off energy by using its control system in a low stress controlled tumble through the atmosphere. This means that the parachutes are deployed at low dynamic pressure, which results in low opening jolts. 

Nobody gets hybrid rocket engines to work well…

We have achieved 95%+ of theoretical max performance on our two most recent engine designs: one motor at 1/20 of the full scale thrust and one motor at 4/5 of the full scale thrust.

We have also demonstrated stable combustion all the way from full thrust down to a 10% thrust level. The stable and smooth combustion is a combination of good injector design, conservative oxidizer mass flux targets, and segmented fuel grain design.

What are your plans after the first flight?

We stand with Boston University’s commitment to open research. We intend to make available the key parts of the work that we have done both from a technical standpoint and from a pedagogical standpoint. There are two caveats to this: there are some export regulations related to rocket hardware, and we have picked up a couple of tips and tricks from various professional companies along the way whose intellectual properties we must respect. However, 90% of what we are learning can and will be released.

As for the second and later flights, there are a couple of payload opportunities that have popped up. We believe that Starscraper will fly operational missions, but it remains to be seen whether those will take place under the BURPG banner or if they will be operated by another to-be-named organization while BURPG keeps advancing the state of the art in affordable rocket technology in other areas.

Where does your financial support currently come from?

About 30% of the funding comes from various departments around Boston University, 60% from corporate sponsors such as Advanced Circuits, GE Aviation, and Raytheon, and 10% from private donors.

How much does a Starscraper launch cost?

Per vehicle reusable hardware: $60k for the first vehicle, $30k to $50k for multiple unit production

Launch operations and propellant: $8k per launch

To date development costs (infrastructure, subscale test vehicles, R&D): $90k 

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