A bunch of friends and I (5 grad students from UF + a friend getting her PhD in psychology) are down in Orlando at the Melrose Center downtown for the NASA SpaceApps HackDay. It’s a nice education and public outreach event that NASA’s been doing for about 5 years now. They invite members of the public to work on challenges that are solvable-ish in a weekend.
For example, a friend and I are working on the 3D print a rocket challenge, but there are more than a dozen challenges. Most deal with coding up apps or games for various purposes: from using satellite data to distinguish between high-level cirrus or contrails, predicting the time you should leave for the airport given weather/traffic, to simulations building a Martian base.
My coding skills are rather paltry, but my 3D printing skills and good-old engineering know-how are pretty good, so I corralled my friend Ally into helping me.
So far, we’ve come up with a modular design based on the Boeing 18-foot diameter 3D-printed composite fuel tank, the RocketDyne AR1 3D-printed rocket engine (supplying 500,000 lbf of thrust @sea level), and a laser-sintered fuselage of my own design.
I’ll keep this post updated throughout the weekend!
Update, day 2 (9:45 am):
Caffeine is a miracle drug. Long live the coffee trees!
Update, day 2 (3:18 pm):
Ally and I are feverishly working on our Prezi presentation. Presentations start at 4:30, so we’re getting there.
Our rocket, dubbed Tribus V (for its three-fold symmetry), is basically a Saturn V equivalent. However, we’ve incorporated 3D-printed fuel tanks and engines, so not only is the rocket more cost-efficient (or should be), its performance is also slightly higher.
It’s actually surprising to me that more than 50 years after the Saturn V was developed we struggled to build a better rocket. The engineering challenges haven’t been altered by improvements in materials technology or even 3D printing. Most of the difficulty is getting several million pounds of rocket moving at several kilometers per second — we struggled to do so in an efficient manner, despite the more efficient engines available today.
We made some rough models of the AR-1 engine in SolidWorks based on some pics we found on the web. We fit 15 (!) of them on the 1st stage of our rocket, which gives us ~7.5 million lbs of thrust — giving us a thrust-to-weight ration about 1.5x more than the Saturn V. This means the Tribus V would (quite literally) shoom off of the pad.
Our second stage only has 5 engines and the third stage only one.
I calculated that with our tankage and estimated weight, with Saturn V specific impulse numbers, that we could get ~130 tonnes into LEO, which isn’t too shabby. It’s probably an underestimate by ~10%, but given that we have no instrumentation or cabling, or anything of the sort, it’s not too bad of an estimate.
Update, 4:15 pm:
Here’s a link to our project page, where you can find our presentation and sources as well as a link to the github page with the SolidWorks files.