Importantly, the missions primary purpose is to test and demonstrate the vehicles capability to safely carry crew to and from Earth orbit, as the first step in the plan of commencing regular ISS missions and commercial space flights.
The extreme velocities and temperatures the vehicle must endure present a major challenge to engineers and makes reentry the most perilous part of a mission.
The danger starts with finding the right angle of the trajectory as the spacecraft enters the upper atmosphere. If it is too steep, the astronauts will experience potentially fatal g-forces, and the friction of the air drag could cause the spacecraft to explode. If it is too shallow, the capsule will instead catastrophically skip off the atmosphere and back into Earth orbit.
The spacecraft will enter the upper atmosphere at 27,000km/hour. That is 7.5km/second, or more than 20 times the speed of sound. In whichever units you prefer this is fast. At these velocities, a very strong shock wave forms around the front of the vehicle, compressing and superheating the air. Managing the immense thermal load is a huge reentry engineering challenge.
At the most extreme stage, the temperature of the air in the shock layer exceeds 7,000C. By comparison, the temperature at the surface of the Sun is around 5,500C. This makes the vehicles heat shield so hot that it starts to glow a process called incandescence. SpaceXs new and advanced PICA-X material heat shield has managed to protect the capsule in test flights, later being recovered in a very charred state.
The air molecules around the vehicle also break down into positively charged atoms and free electrons a so-called plasma. When some of the molecules recombine, excess energy is released as photons (light particles) giving the air around the vehicle an amber glow.
This plasma layer may be beautiful, but it can cause radio blackouts. When an electron travels along a conductive wire, we have electricity. Similarly, when free electrons move through the plasma around the vehicle, we have an electric field. If the electric field becomes too strong, it can reflect and attenuate the radiowaves trying to reach the spacecraft.
Blackout not only leads to a loss of connection to on-board crew and flight data, it can also make remote control and guidance impossible. The Apollo missions, the Mars Pathfinder and the recent, failed 2018 Soyuz rocket launch all incurred communications blackout on the order of minutes. NASA mission control are anticipating a nervous six minutes of blackout during the peak heating phase of Crew Dragons return if anything goes wrong during this time, its in the hands of the astronauts.
Another risky stage is the parachute-assisted landing. The Crew Dragon will deploy four parachutes upon the final stage of reentry, as the vehicle descends toward a gentle splashdown in the Atlantic Ocean off the coast of Florida. This manoeuvre has been tested by SpaceX 27 times prior to next weeks crewed landing, so it should work.
A successful landing will have huge implications lowering the cost of space exploration through the use of reusable rockets and enabling private space exploration. While SpaceX engineered the Crew Dragon vehicle under contract to NASA, the company is free to use the spacecraft for commercial flights without NASA involvement after operational certification.
SpaceX has a partnership with commercial aerospace company Axiom Space, which has the ultimate goal of building the worlds first commercial space station. The proposed commercial activities for the station are broad: from in-space research and manufacturing to space exploration support.
Then there is space tourism. Private citizens are already queuing for their ticket to space, and with a successful Crew Dragon splashdown, they wont be waiting long. American space tourism company, Space Adventures (partnered with SpaceX), are planning to offer zero-gravity atmospheric flights, orbital flights with a spacewalk option and laps of the Moon by late 2021.
Whether the costs, environmental impact and dangers of spaceflight is justified for space tourism is debatable. As this articles shows, the required safety briefing for Space Adventure ticket holders will be much more comprehensive than your regular please take a moment to read the safety card in the seat pocket in front of you.
Heather Muir, PhD in Computational Physics, University of Cambridge
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Read this article:
- 'It just sounds like a thud': astronomers hear biggest cosmic event since big bang - The Guardian - September 4th, 2020
- The Sky This Week from September 4 to 11 - Astronomy Magazine - September 4th, 2020
- A nearby supernova could have caused the Devonian mass extinction - Astronomy Magazine - September 4th, 2020
- Great Basin National Park astronomy festival to be held mostly virtually this month - FOX5 Las Vegas - September 4th, 2020
- Indian astronomers discover one of the farthest galaxies in the universe - Moneycontrol - September 4th, 2020
- Breaking down the astronomical number of mail-in ballot requests in NC - CBS17.com - September 4th, 2020
- Meet The Woman Behind Ninjas Astronomical Success: Jessica Blevins - Forbes - September 4th, 2020
- Tesla To Cash in on Astronomical Stock Price With $5 Billion Capital Raise - The Drive - September 4th, 2020
- A supernova that left chaos in its wake - SYFY WIRE - September 4th, 2020
- The ghost of an angry black hole still haunts this galaxy - SYFY WIRE - September 4th, 2020
- Amazon Satellites Add to Astronomers Worries About the Night Sky - The New York Times - August 10th, 2020
- The Last Stargazers? Why You Will Never See An Astronomer Looking Through A Telescope - Forbes - August 10th, 2020
- Ceres: An ocean world in the asteroid belt - Astronomy Magazine - August 10th, 2020
- Small stars are vital to dispersing the building blocks of life - Astronomy Magazine - August 10th, 2020
- Bookmonger: 'The Last Stargazers' is a behind-the-scenes look at astronomy - Discover Our Coast - August 10th, 2020
- Explore Pollinators And Islamic Astronomy This Week With PEEC - Los Alamos Reporter - August 10th, 2020
- Astronomers May Have Identified The Biggest Impact Structure in Our Solar System - ScienceAlert - August 10th, 2020
- ASTRONOMY: When it comes to night sky, be prepared! - Mdcp.nwaonline.com - August 10th, 2020
- Astronomers Say That Planets Orbiting Black Holes Are Called "Blanets" - Futurism - August 10th, 2020
- Because the Universe isn't weird enough: Black hole planets may exist. - SYFY WIRE - August 10th, 2020
- When the supermassive black hole's away, the stars will play - SYFY WIRE - August 10th, 2020
- A Star Went Supernova in 1987. Where Is It Now? - The New York Times - August 10th, 2020
- Astronomers Part of Pasadena-Based Carnegie's Team Reveal 'Last of its Kind' Remnant of Ancient Globular Cluster - Pasadena Now - August 10th, 2020
- NASA is changing some insensitive space terminology - heres why - Linlithgow Journal and Gazette - August 10th, 2020
- VLT Measures Main-Belt Asteroid Euphrosyne and Its Moon | Astronomy - Sci-News.com - August 10th, 2020
- View On Astronomy: Perseids meteor shower an annual attraction - The Independent - August 10th, 2020
- A Globular Cluster was Completely Dismantled and Turned Into a Ring Around the Milky Way - Universe Today - August 10th, 2020
- Could JWST Discover the Largest Object in the Universe? Now. Powered by - Now. Powered by Northrop Grumman. - August 10th, 2020
- Here's How Exploding Stars Forged The Calcium in Your Teeth And Bones - ScienceAlert - August 10th, 2020
- Astronomers find the largest impact crater in the solar system - FREE NEWS - August 10th, 2020
- See the 'space butterfly' astronomers captured from thousands of light years away - CNN - August 8th, 2020
- The best place to see stars from Earth also happens to be the coldest place on the planet - Space.com - August 8th, 2020
- Astronomical First: Differences Detected Between Discs of Active and Non-Active Galaxies - SciTechDaily - August 8th, 2020
- Rivers on ancient Mars may have flowed beneath sheets of ice - Astronomy Magazine - August 8th, 2020
- Move over, SpaceX Amazon is sending its own satellites into orbit - Salon - August 8th, 2020
- Amateur Astronomers Find a Saturn-Sized Planet in The Habitable Zone of a Distant Star - ScienceAlert - August 8th, 2020
- Astronomy Apps Market Expected to Witness the Highest Growth 2025 - AlgosOnline - August 8th, 2020
- Saturn-Sized Exoplanet Discovered by the Gravitational Wobble in the Small, Cool Star It Orbits - SciTechDaily - August 8th, 2020
- 9 of the Best Books About Astronomy - Book Riot - August 8th, 2020
- Prof Melvin Hoare is Driving Development in Africa with Radio Astronomy - Space in Africa - August 8th, 2020
- Top astronomical events to look forward to in August 2020 - Wales Online - August 7th, 2020
- A Strange Planet has been Found thats Smaller than Neptune But 50% More Massive - Universe Today - August 7th, 2020
- What planets should we search to find alien life? - Astronomy Magazine - August 4th, 2020
- Mars 2020 launch: NASA's Perseverance rover ready for the Red Planet - Astronomy Magazine - August 4th, 2020
- A Movie of the Evolving Universe Is Potentially Scary - Scientific American - August 4th, 2020
- Mini-Neptunes could be super-Earths with bloated atmospheres of water - Astronomy Magazine - August 3rd, 2020
- A Movie of the Evolving Universe, Potentially Scary - Scientific American - August 3rd, 2020
- Study: Universe Might Be 1.2 Billion Years Younger | Astronomy - Sci-News.com - August 3rd, 2020
- Stargazing: Astronomers estimate Earth-size planets number in the billions - Oklahoman.com - August 3rd, 2020
- Boosting the representation of Black students - Symmetry magazine - August 3rd, 2020
- There are Natural Starshades Out There, Which Would Help Astronomers Image Exoplanets - Universe Today - August 3rd, 2020
- How astronomers rediscovered a lost world - EarthSky - August 3rd, 2020
- Antonia: A Maury to be Proud Of - Vashon-Maury Island Beachcomber - August 3rd, 2020
- Neuroscience, astronomy, animal behavior, and more: Black scientists are showcasing their research on social media - Massive Science - August 2nd, 2020
- The CO2 Elephant in the Room: Curbing the Carbon Footprint of Astronomy - Astrobites - August 2nd, 2020
- Scientists Find The Best Place on Earth For Viewing The Night Sky, But There's a Catch - ScienceAlert - August 2nd, 2020
- Mind-blowing Astronomy Photo of the Year competition reveals strange galaxies and space portals - The Sun - August 2nd, 2020
- Innovative balloon-borne telescope promises rich infrared reward - Astronomy Now Online - August 2nd, 2020
- Astronomers just spotted ancient stars lurking at the edges of our galaxy - BGR - August 2nd, 2020
- Astronomers found a bunch of ancient stars displaced by our galaxy - BGR - July 31st, 2020
- Astronomy - Wikipedia - July 31st, 2020
- astronomy | Definition & Facts | Britannica - July 31st, 2020
- Astronomy for Beginners | Night Sky Facts, FAQs ... - July 31st, 2020
- What is Astronomy? Definition & History | Space - July 31st, 2020
- Mars shifting sands revealed by long-term observations - Astronomy Magazine - July 31st, 2020
- Astronomers nab the farthest visible explosion from a neutron star collision ever seen - SYFY WIRE - July 31st, 2020
- A&M-Commerce Planetarium & Observatory Offer the Universe to Students and Community - frontporchnewstexas.com - July 31st, 2020
- This Is the Single Best Place To Stargaze on Earth - Popular Mechanics - July 30th, 2020
- Apple TV+ has Acquired the Rights to the Original Astronomy Documentary 'Fireball' - Patently Apple - July 30th, 2020
- Hitting the reset button | Lifestyles - Enid News & Eagle - July 29th, 2020
- Astronomers Discover One of the Coolest Transiting Gas Giants | Astronomy - Sci-News.com - July 29th, 2020
- A Faraway Solar System Is an Uncanny Reflection of Our Own - The Atlantic - July 29th, 2020
- Gamma-Ray Telescopes Can Measure the Diameters of Other Stars - Universe Today - July 29th, 2020
- Astronomers Capture the First Ever Photo of Two Planets Orbiting a Sun-Like Star - PetaPixel - July 29th, 2020
- Thanks to astronomy, researchers in Texas figure out the time, date, and year of Vermeer's "View of Delft" - Art Critique - July 29th, 2020
- To Mars! Perseverance rover all set to launch on Thursday 30 July - SYFY WIRE - July 29th, 2020
- Thinking Outside the Classroom: Astronomical phenomena you can see during the day - Summit Daily News - July 29th, 2020
- Astronomy news: Never before seen cosmic structures spotted in distant galaxy - Daily Express - July 26th, 2020
- Astronomers Do the Math to Figure Out Exactly When Johannes Vermeer Painted this, More than 350 Years Ago - Universe Today - July 26th, 2020
- Pinning down the suns birthplace just got more complicated - Science News - July 26th, 2020