RocketSTEM Issue #5 - January 2014 | Page 41

Lynx spacecraft to give big boost to space tourism By Sherry Valare Like a scene out of a futuristic movie, imagine an airplane that could take off from a runway, fly sub-orbital, and return to the ground with a runway landing. The concept seemed pretty far-fetched not even ten years ago. Now, a handful of commercial spaceflight companies are breathing life into what was once only sentiment. The Reuseable Launch Vehicle (RLV) industry is heating up fast. With several different companies having similar spacecraft in various stages of production or testing, the race is on, and XCOR Aerospace is close to the finish line. XCOR has developed an RLV they call “Lynx”. It is powered by a fully reusable rocket propulsion system that gives it the unique capability of taking off and landing horizontally, while most other companies are using rocket rides and air-launch methods to take to the skies. Some of the advantages the Lynx spacecraft boasts are a low operating cost and the capability of fulfilling four flights per day with two-hour turnarounds in between, without any compromise to the safety of the vehicle. Lynx will be able to operate out of any spaceport with a 7,900 foot runway, though the first flights will occur at the Mojave Air and Spaceport in California. Lynx will take paying customers for rides as tourists, and transport research payloads, as well. A flight in the Lynx will last about thirty minutes. Fueled by a burning mix of liquid oxygen (LOX) and kerosene, 2,900 pounds of thrust will be created by each of the four XR-5K18 rocket engines residing in the back of the fuselage. This will lift the vehicle through takeoff and ascent, where it will reach a maximum airspeed of Mach 2.9 until about 3 minutes into flight. At this point, Lynx will be around 190,000 feet in the air, where it will turn off its engines and coast upwards, until it reaches apogee at 328,000 feet. It will experience weightlessness for about 4.6 minutes, followed by re-entry, with its passengers experiencing gravity four times greater than normal. The final leg of the trip is a spiral glide back to the runway where Lynx will safely touch down and roll to a stop. Jeff Greason, President of XCOR Aerospace, explains, “It takes about a minute after engine light to go supersonic. At about 70 to 80,000 feet, the sky will start to turn dark, and by 100,000 feet, it’s gone black. You will get an opportunity to maneuver, using the reaction control systems – GW&