By Jonny Lupsha, Wondrium Staff Writer
Elon Musk’s SpaceX will launch a space mission with two tickets up for grabs, USA Today reported. Members of the public can enter to win a seat on a space expedition, commanded by a payment systems entrepreneur, that will be flown as part of Musk’s private space program. Rocket science has evolved significantly since World War II.
According to USA Today, members of the public will soon have a chance to see Earth from orbit. “A tech billionaire will command SpaceX’s first all-civilian launch to orbit later this year, but the mission includes a twist: Members of the public can enter to fly in one of Crew Dragon’s seats,” the article said.
“Jared Isaacman, a payment systems entrepreneur and avid pilot, confirmed he purchased a Crew Dragon mission from SpaceX for a multi-day trip around Earth slated to launch from Kennedy Space Center before the end of this year. This mission is allowing members of the public to join the trip that will complete an Earth orbit every 90 minutes.”
The proceeds from the enter-to-wing drawing to win a seat on the flight—and the awareness campaign via setting up a website to share the story on Twitter to earn a seat—will benefit St. Jude Children’s Research Hospital in Memphis, Tennessee, as part of an effort to raise $200 million or more and awareness for the facility. The SpaceX launch represents a clear evolution from the early days of U.S. rocket technology, which originated after World War II.
Rocket propulsion offers a distinctly different approach to navigating the skies (and the stars) from helicopters or airplanes.
“Rockets do not beat the air into submission and do not depend in any way on aerodynamic forces to generate lift,” said Dr. James W. Gregory, Professor of Mechanical and Aerospace Engineering at The Ohio State University, in a lecture for The Great Courses. “Rockets also do not have to rely on the atmosphere for combustion, which is at the heart of all jet engines, and all internal combustion engines.
“However, rockets must still pass through the atmosphere on their way to space, and in so doing, the rocket flight must remain stable.”
Early post-WWII rockets like the German V-2 had sets of fins to perform some aerodynamic function, but rocket stability moved on. Dr. Gregory said that modern rockets are kept stable because they’re gimbaled, meaning that the thrust from the rocket engines is vectored as needed to keep the rocket stable. In simpler terms, it looks as though the bottom of the rocket wiggles to keep it headed in the right direction.
Most modern rockets use gimbals instead of fins in order to reduce weight and aerodynamic drag of their launch vehicle. Why the difference?
“Unlike a jet, rocket engines can easily operate outside the Earth’s atmosphere, where there is absolutely no oxygen available for the combustion process,” Dr. Gregory said. “This is because rockets carry along their own oxidizer needed for combustion of fuel. In fact, the presence of the atmosphere is mainly a limiting factor for rockets; it drives some of the structural design requirements.”
Thus, the dynamic pressure, which is proportional to the density and square of velocity, directly influences the aerodynamic loading on the rocket body.
With gimbaled thrust and other aspects of a rocket that are designed specifically for spacefaring purposes, vehicles like Elon Musk’s SpaceX shuttles will have a much smoother ride than they would have 60 years ago.
This article contains material taught by James W. Gregory from his course The Science of Flight. Dr. Gregory is Professor of Mechanical and Aerospace Engineering at The Ohio State University. He received a bachelor of science degree in Aerospace Engineering from Georgia Tech and a doctorate in Aeronautics and Astronautics from Purdue University.