The Orion’s Heat Shield Gets a Scorching on Re-entry

Yes, she’s a little worse for wear, isn’t she? But then again, that’s what atmospheric re-entry and 2200 °Celsius (4000 °Fahrenheit) worth of heat will do to you! Such was the state of the heat shield that protected NASA’s Orion Spaceship after it re-entered the atmosphere on Dec. 5th, 2014. Having successfully protected the craft during it’s test flight, the shield was removed and transported to the Marshall Space Flight Center in Huntsville, Alabama, where it arrived on March. 9th.

Since that time, a steady stream of NASA employees have been coming by the facility to get a look at it while engineers collect data and work to repair it. In addition to being part of a mission that took human-rated equipment farther out into space than anything since the Apollo missions, the heat shield is also living proof that NASA is restoring indigenous space capability to the US.

First unveiled by NASA in May of 2011, the Orion Multi-Purpose Crew Vehicle (MPCV) was intrinsic to the Obama administration’s plan to send astronauts to a nearby asteroid by 2025 and going to Mars by the mid-2030’s. In addition to facilitating these long-range missions, the Orion spacecraft would also handle some of the routine tasks of spaceflight, such as providing a means of delivering and retrieving crew and supplies from the ISS.

NASA Orion spacecraft blasts off atop 1st  Space Launch System rocket in 2017 - attached to European provided service module – on an enhanced m mission to Deep Space where an asteroid could be relocated as early as 2021.   Credit: NASA
Artist’s concept of the Orion spacecraft being sent into orbit atop the first Space Launch System (SLS) rocket in 2017. Credit: NASA

The uncrewed test flight that took place on December 5, 2014, known as Exploration Flight Test 1 (EFT-1), was intended to test various Orion systems, including separation events, avionics, heat shielding, parachutes, and recovery operations prior to its debut launch aboard the Space Launch System,

This design of this mission corresponded to the Apollo 4 mission of 1967, which demonstrated the effectiveness of the Apollo flight control systems and the heat shields ability to withstand re-entry conditions, as part of the spacecraft’s return from lunar missions.

After being retrieved, the heat shield was transported by land to the Marshall Space Flight Center, where it was offloaded and transferred to a large support structure so engineers could perform studies on it for the next three months.

This will consist of collecting samples from the shield to measure their char layers and degree of erosion and ablation, as well as extracting the various instruments embedded in the heat shield to assess their performance during re-entry.

The heat shield arrived March 9 at Marshall, where experts from the Center and NASA’s Ames Research Center will extract samples of the ablative material, or Avcoat. Image Credit:  NASA/MSFC/Emmett Given
The heat shield arriving at Marshall on March 9th, where experts from the Center and NASA’s Ames Research Center. Credit: NASA/MSFC/Emmett Given

After the analysis is complete, technicians will load the shield into the 7-axis milling machine and machining center, where it will be grind down to remove the remaining material covering. Known as Avcoat, this heat-retardant substance is similar to what the Apollo missions used, with the exception of toxic materials like asbestos.

This material is used to fill the 320,000 honeycomb-like cells that make up the outer layer of the shield. When heated, the material burns away (aka. ablates) in order to prevent heat being transferred into the crew module. This shield is placed over the craft’s titanium skeleton and carbon-fiber skin, providing both protection and insulation for the interior.

Once all the Avcoat is removed and only the skeletal frame remains, it will be shipped to the Langley Research Center in Hampton, Virginia, for more tests. Since the Orion was returning from a greater distance in space than anything since Apollo, it experienced far greater heat levels than anything in recent decades, reaching as high as 2200 °C (4000 °F).

During Orion's test flight the heat shield reached temperatures of about 4,000 degrees Fahrenheit. Instrumentation in the heat shield measured the rise of the surface and internal temperatures during re-entry as well as heating levels and pressures. Image Credit:  NASA/MSFC/Emmett Given
Instrumentation in the Orion heat shield (visible here) measured the rise of the surface and internal temperatures during re-entry. Credit: NASA/MSFC/Emmett Given

Instrumentation in the shield measured the rise of the surface and internal temperatures during re-entry as well as the ablation rate of the shield’s coating. Over the next few months, NASA experts will be pouring over this data to see just how well the Orion shield held up under extreme heat. But so far, the results look positive – with only 20% of the Avcoat burning away on the test-flight re-entry.

In the future, the Orion spacecraft will be launched on Space Launch System on missions that will take it to nearby asteroids and eventually Mars. The first mission to carry astronauts is not expected to take place until 2021 at the earliest.

Further Reading: NASA

Most Powerful Solid Rocket Booster Ignites in Milestone Test, Propelling NASA on Path to Deep Space

At the Orbital ATK test facility, the booster for NASA’s Space Launch System rocket was fired for a two minute test on March 11. The test is one of two that will qualify the booster for flight before SLS begins carrying NASA’s Orion spacecraft and other potential payloads to deep space destinations. Image Credit: NASA
Watch the complete test firing video below[/caption]

KENNEDY SPACE CENTER, FL – NASA’s goal of sending humans back to deep space in the next decade advanced a major step forward today, March 11, with the successful ground test firing of the largest and most powerful solid rocket booster ever built that will be used to propel NASA’s Space Launch System (SLS) rocket and manned Orion spacecraft to destinations including the Moon, Asteroids and Mars.

The two minute long, full duration static test firing of the motor marked a major milestone in the ongoing development of NASA’s SLS booster, which is the most powerful rocket ever built in human history.

The booster known as qualification motor, QM-1, is the world’s largest solid rocket motor and was ignited at about 11:30 a.m. EST by prime contractor Orbital ATK at the newly merged firms test facility in Promontory, Utah.

Video caption: Space Launch System Booster Passes Major Ground Test on Mar. 11, 2015. The 5 segment solid rocket booster being developed for the SLS rocket fired for two minutes, the same amount of time it will fire when it lifts the SLS off the launch pad, and produced about 3.6 million pounds of thrust. The test was conducted at the Promontory, Utah test facility of commercial partner Orbital ATK. Credit: NASA

It burned for exactly the same amount of time as it will during flights of the SLS booster which will lift off from Launch Complex 39B at the Kennedy Space Center in Florida.

The booster test firing was the second of two major do or die tests conducted by NASA in the past three months in support of the agency’s “Journey to Mars” strategy to develop the infrastructure required to send astronauts to an asteroid in the next decade and beyond to the Red Planet in the 2030s.

“The work being done around the country today to build SLS is laying a solid foundation for future exploration missions, and these missions will enable us to pioneer far into the solar system,” said William Gerstenmaier, NASA’s associate administrator for human exploration and operations, in a statement.

“The teams are doing tremendous work to develop what will be a national asset for human exploration and potential science missions.”

Orbital ATK’s five segment rocket motor is assembled in its Promontory, Utah, test stand where it is being conditioned for the March 11 ground test.  Credit: Orbital ATK
Orbital ATK’s five segment rocket motor is assembled in its Promontory, Utah, test stand
where it is being conditioned for the March 11 ground test. Credit: Orbital ATK

The 5-segment booster produces 3.6 million lbs of maximum thrust which equates to more than 14 Boeing 747-400s at full takeoff power!

The new 5-segment booster was derived from the 4-segment booster used during NASA’s three decade long Space Shuttle program. One segment has been added and therefore the new, longer and more powerful booster must be requalified to launch the SLS and humans.

A second test is planned a year from now and will qualify the boosters for use with the SLS.

“This test is a significant milestone for SLS and follows years of development,” said Todd May, SLS program manager.

“Our partnership with Orbital ATK and more than 500 suppliers across the country is keeping us on the path to building the most powerful rocket in the world.”

Solid rocket boosters separate from SLS core stage in this artists concept. Credit: NASA
Solid rocket boosters separate from SLS core stage in this artists concept. Credit: NASA

The QM-1 booster weighs in at 1.6 million pounds and required several month of conditioning to heat to the 90 degrees temperature required to conduct the static fire test and thereby qualify the booster design for high temperature launch conditions. It was mounted horizontally in the test stand and measured 154 feet in length and 12 feet in diameter and weighs 801 tons.

Temperatures inside the booster exceeded over 5,600 degrees F.

The static fire test was exquisitely planned to collect data on 103 design objectives as measured through more than 534 instrumentation channels on the booster as it was firing.

The second booster test in March 2016 will be conducted to qualify the propellant temperature range at the lower end of the launch conditions at 40 degrees F.

The first stage of the SLS will be powered by a pair of the five-segment boosters and four RS-25 engines that will generate a combined 8.4 million pounds of liftoff thrust.

The maiden test flight of the SLS is targeted for no later than November 2018 and will be configured in its initial 70-metric-ton (77-ton) version with a liftoff thrust of 8.4 million pounds. It will boost an unmanned Orion on an approximately three week long test flight beyond the Moon and back.

NASA plans to gradually upgrade the SLS to achieve an unprecedented lift capability of 130 metric tons (143 tons), enabling the more distant missions even farther into our solar system.
The first SLS test flight with the uncrewed Orion is called Exploration Mission-1 (EM-1) and will launch from Launch Complex 39-B at the Kennedy Space Center.

NASA’s first Orion spacecraft blasts off at 7:05 a.m. atop United Launch Alliance Delta 4 Heavy Booster at Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida on Dec. 5, 2014.   Launch pad remote camera view.   Credit: Ken Kremer - kenkremer.com
NASA’s first Orion spacecraft blasts off at 7:05 a.m. atop United Launch Alliance Delta 4 Heavy Booster at Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida on Dec. 5, 2014. Launch pad remote camera view. Credit: Ken Kremer – kenkremer.com

Orion’s inaugural mission dubbed Exploration Flight Test-1 (EFT) was successfully launched on a flawless flight on Dec. 5, 2014 atop a United Launch Alliance Delta IV Heavy rocket Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.

Orion’s inaugural mission dubbed Exploration Flight Test-1 (EFT) was successfully launched on a flawless flight on Dec. 5, 2014 atop a United Launch Alliance Delta IV Heavy rocket Space Launch Complex 37 (SLC-37) at Cape Canaveral Air Force Station in Florida.

Wide view of the new welding tool at the Vertical Assembly Center at NASA’s Michoud Assembly Facility in New Orleans at a ribbon-cutting ceremony Sept. 12, 2014.  Credit: Ken Kremer – kenkremer.com
Wide view of the new welding tool at the Vertical Assembly Center at NASA’s Michoud Assembly Facility in New Orleans at a ribbon-cutting ceremony Sept. 12, 2014. Credit: Ken Kremer – kenkremer.com

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer
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Learn more about MMS, Mars rovers, Orion, SpaceX, Antares, NASA missions and more at Ken’s upcoming outreach events:

Mar 11: “MMS, Orion, SpaceX, Antares, Curiosity Explores Mars,” Kennedy Space Center Quality Inn, Titusville, FL, evenings