Pioneering Earth’s Escape 3 February 2006Posted by BT in Spaceflight.
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California’s desert brimmed with excitement on October 4, 2004, as Brian Binnie successfully piloted SpaceShipOne to an altitude of more than 367,000 feet (Brean, 2004). Forty seven years after Sputnik ignited the space race; mankind’s newest accomplishment captured the X Prize for designer Burt Rutan and sponsor Paul Allen. Loosely based on the Orteig Prize, which Charles Lindbergh won with his historic crossing of the Atlantic Ocean, the X Prize was founded to inspire privately funded space exploration and tourism. Currently, this vision is being realized; Virgin Atlantic is funding Rutan and his company, Scaled Composites, to build a larger version of SpaceShipOne as charter for suborbital space tourists. Proclaiming their vehicles to cost less than government counterparts while maintaining a higher degree of safety, this private sector industry has recently promised to make space tourism available to the masses. While vacationing in the cosmos would appeal to many people, the question of whether this industry will become viable in the immediate future garners much debate. Currently, this technology is unable to live up to its much hyped promises. Many problems occurred with SpaceShipOne which were never remedied or brought to the public’s attention, giving the program a false air of safety. Additionally, funding for this fledgling industry remains virtually nonexistent due to our nation’s current economic plight, tickets optimistically projected to cost as much as a house, and federal regulations threatening to blacken the opportunity for investors.
One benefit of private industry space tourism is the relatively low cost. Richard Branson, of Virgin Atlantic and most recently Virgin Galactic, announced a price tag of $200,000 per person for a suborbital flight. In conjunction, soda drink maker 7-Up has agreed to give a free ticket to the lucky winner of a contest expected to be held in 2005 (Brean, 2004). Space tourism is not a novel idea; already two humans have been tourists aboard the International Space Station. American Dennis Tito and South African Mark Shuttleworth each paid twenty million dollars to gain passage on a Russian Soyuz (Jones, 2005). Of course, public willingness to purchase tickets for suborbital flight depends on the safety of the machine which will carry them there.
Two of the most touted safety features are SpaceShipOne’s feathering system and hybrid rocket motor. Feathering is a unique procedure used to dissipate energy upon re-entering Earth’s atmosphere, vital for survivability of the completely composite vehicle. Additionally, SpaceShipOne’s motor, developed by SpaceDev, burns rubber fuel and laughing gas (Coppinger, 2004). This has the ability to be turned on and off during flight while maintaining a high level of thrust and providing easy and safe storage of the propellants. Pilots of SpaceShipOne remained at the top of their game flying a simulator replica of the tiny craft. During its three space flights, SpaceShipOne has maintained an impeccable safety record with zero fatalities (Antczak, 2004). Unfortunately, there exist many flaws in the design of this vehicle and mishaps occurred on almost every flight. Little has been done to remedy these problems, proving private space industry neither has the technological readiness nor the regulatory ability to pioneer space tourism.
Although SpaceDev’s motor for SpaceShipOne uses extremely safe propellants, there are serious flaws in design which have remained unchecked and are potentially lethal. During one test firing of the motor, a shutoff valve was unable to fully close and the subsequent fire destroyed a test stand (Dornheim, “Trials,” 2004). Additionally, inadequacies in SpaceShipOne’s design make landing without igniting the motor extremely hazardous. This was explained by pilot Peter Siebold following an April 8 flight in 2004 when loss of control prompted serious consideration of an aborted ascent. High landing weight due to having full propellant was considered too risky for both the pilot and his expensive craft. Additionally, dumping the motor’s oxidizer, which only accounts for half of the propellant and is the only part which can be cast away without ignition, would cause SpaceShipOne’s center of gravity to move out of limits and would certainly lead to an accident. In the end, the only “safe” option was to light the motor despite concerns with the aircraft’s stability (Dornheim, “Trials,” 2004).
SpaceShipOne has major design flaws with regard to the ship’s stability. Due to a lack of a stability augmenter, all of the pilots of SpaceShipOne have been pushed considerably into their seats directly after ignition, often pulling the control stick back in the process. Senior pilot Mike Melvill explains the process (Dornheim, “Trials,” 2004), “It’s really difficult to handle in the first 10-15 sec. We jacked up the early oxidizer flow for more thrust but it gives unstable flow–in the video you can see your head jerk back and forth. You need instruments to round the corner, it’s too disorienting.” Additionally, due to poor flight characteristics of SpaceShipOne at high weights, the amount of rocket oxidizer was reduced without modifying the size of the fuel tanks. When the motor is ignited, all of the oxidizer moves toward the back of the fuel tanks, exacerbating the ship’s pitch up tendencies (Dornheim, “Trials,” 2004).
In addition, uncontrollable rolls have occurred at the peak of almost all of the flights. This is due to control ineffectiveness in the thin upper atmosphere and side forces imposed on the aircraft by the feathering mechanism. Rutan admitted poor design (Dornheim, “Spin,” 2004) when describing the causes of the upper atmosphere rolls, “SpaceShipOne has too much dihedral effect, or that sideslip causes too much rolling moment. This makes it too sensitive to side gusts or rudder input, which is exacerbated by the short wingspan with low roll inertia and damping.” In classic fashion, Rutan declined to make improvements to his design (Dornheim, “Spin,” 2004) saying, “the problem has to be lived with in SpaceShipOne.”
With the great risks involved, it is not a surprise that congress has stepped in to pass regulations. The Commercial Launch Act was pushed through the house in November of 2004 (Klotz, 2004). In its broadest scope of regulatory ability, the act requires the Federal Aviation Administration to inform space tourists of the possible dangers and experimental nature of privately funded space tourism. A waiver of consent would be collected by all passengers, much like with other extreme activities, such as sky diving or rafting. Unfortunately, one area which was not covered by the act is the possible damage and death to persons on the ground following a catastrophic launch. This seems to be an area where an act will be set in place after an unfortunate event occurs. With the uncertainty presented by congress with regard to unintentional damage and casualties, this may be a sticking point for investors who realize the inherent dangers present in space travel of any kind and the inevitability of an accident.
Already 18,000 people have reserved seats aboard Virgin Galactic flights (Werner, 2005). Using projected ticket prices, this makes private space tourism only a three and one half billion dollar industry. Considering the amount of technology needed to vastly improve safety over the existing standard of SpaceShipOne and the trepidation of investors over future congressional actions, it seems private space tourism has neither the funding nor the technological prowess required to fulfill its promises of family trips to the cosmos within the immediate future. With public excitement for space tourism dwindling and no signs of further development on the horizon, it seems private space tourism may have been just a test of the waters, instead of a plunge into the brave new world of tomorrow.
Antczak, J. (2004, September). Aviators planning space shot [Electronic Version]. Pittsburgh
Brean, H. (2004, October). SpaceShipOne successful again [Electronic version]. Las Vegas
Review – Journal.
Coppinger, R. (2004, November). SpaceDev wins more USAF cash to develop small launch
Vehicle [Electronic version]. Flight International.
Dornheim, M. A. (2004). Spin control; SpaceShipOne proved it can meet the altitude/payload
requirement of the X-Prize. The next step: do it again by Oct. 13 [Electronic version]. Aviation Week & Space Technology: World News & Analysis, 161(13), 28.
Dornheim, M. A. (2004). Trials of SS1; winning the X Prize took courage. Next craft will have
electronic assist [Electronic version]. Aviation Week & Space Technology: World News & Analysis, 161(15), 36.
Jones, T. D. (2005, February). Coming soon: ticket to ride [Electronic version]? American
Institute of Aeronautics and Astronautics.
Klotz, I. M. (2004, November). Space race 2: congress weighs in [Electronic version]. United
Werner, E. (2005, February). Entrepreneurs promise outer-space vacations, but there are risks
[Electronic version]. The Associated Pre
Hello World 3 February 2006Posted by BT in Misc..
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“If I have seen further it is by standing on the shoulders of giants.” -Isaac Newton
Currently spaceflight in the United States is experiencing tremendous competition from other countries and private sector industry. As I am currently attending college to become a rocket scientist, I am inclined to provide commentary on current events when time permits. Enjoy!