NASA Prepares for High-Stakes Orion Heat Shield Test with First Crewed Lunar Mission
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The Challenge of Re-entry
Returning spacecraft safely to Earth is a critical and demanding phase of spaceflight. NASA is preparing for a particularly challenging re-entry, one it hasn’t attempted in over 50 years: bringing astronauts back from a lunar mission. The upcoming flight will mark the first time astronauts travel aboard the Orion spacecraft, and a key objective is to rigorously test the performance of its heat shield.
Re-entry subjects vehicles to extreme stress. The 2003 Space Shuttle Columbia disaster, where the orbiter broke apart during re-entry from low-Earth orbit, tragically demonstrated the risks, resulting in the loss of all seven astronauts. NASA’s investigation determined a breach during launch led to the catastrophic failure.
Orion’s mission is substantially more demanding than previous crewed re-entries. it will be returning from the Moon, traveling at much higher velocities and generating far greater energy, placing even more strain on the heat shield.
Heat Shield Concerns and Testing
A 2022 uncrewed test flight of Orion revealed issues with the heat shield’s performance, raising concerns about crew safety. NASA promptly launched an investigation to understand and address the anomalies. The agency is now planning to launch Orion with a crew as early as february 2024.
During re-entry, Orion will initially encounter the Earth’s atmosphere at approximately 25,000 miles per hour, facing temperatures reaching 5,000 degrees Fahrenheit. The Orion spacecraft, built by Lockheed Martin for NASA, features a heat shield nearly 17 feet in diameter, positioned on the underside of the vehicle.
This shield is covered with an “ablative” material. This material is designed to protect the spacecraft by burning away in a controlled fashion, carrying heat away from the capsule during the intense re-entry process.
What is Ablative Heat Shield Technology?
Ablative heat shields are a crucial technology for high-speed re-entry. Rather of reflecting heat, they dissipate it through a phase change – the material vaporizes, taking thermal energy with it. This process prevents the extreme heat from reaching the spacecraft’s structure and its occupants. The Apollo command module also used an ablative heat shield during lunar return missions.
