What is Orion’s technological significance?
by Anthony Young
|Many assume Orion is bristling with all the latest in technology in software, design, manufacturing, materials, human factors, and practically every other aspect.|
The Orion capsule was originally conceived as America’s next human spacecraft after the Space Shuttle and a key hardware component of Project Constellation. The fits and starts of the Orion program are well known to human spaceflight advocates, so there is no need to rehash that here. Previous articles here have documented some of this capsule’s design evolution and chaotic history (see “The next logical step becomes logical”, The Space Review, May 3, 2010, and “Memorials and malaise”, The Space Review, January 31, 2011)
Nevertheless, many assume Orion is bristling with all the latest in technology in software, design, manufacturing, materials, human factors, and practically every other aspect. The purpose of this article is to examine some of that technology and the rationale behind it.
To better understand Orion’s technology in context, it is worth looking at Orion’s Exploration Flight Test 1 (EFT-1) objectives. There were four primary flight test objectives Lockheed Martin and NASA wanted to achieve with EFT-1:
In addition to these primary objectives, tests were also planned for the crew module’s electrical power storage and distribution; cabin pressure and thermal control; command and data handling; communications and tracking; guidance, navigation and control; reaction control system propulsion, and flight software and computers.
Since there was no crew on this flight, the environmental control and life support system, crew seats, and crew-operable hatches were not in this Orion capsule. In addition, there was no fully-function service module on this flight. Instead, there was a structural simulator built by Lockheed Martin. The service module for future missions is being built by the European Space Agency (ESA).
For example, computer processors and software are not cutting edge. The prime contractor for Orion, Lockheed Martin, did not choose to create a proprietary new flight computer for the capsule. Instead, with NASA’s input, it selected the flight computer built by Honeywell International used on the Boeing 787 jetliner. Two flight-proven IBM PowerPC 750FX single-core processors are employed in each of the three flight computers; these processors were first used in 2002.
Matt Lemke, NASA’s deputy manager for Orion’s avionics, power and software team explained the reasons why this was done. “Compared to the [Intel] Core i5 in your laptop, it’s much slower… It’s probably not any faster than your smartphone,” he revealed. “But it’s not about the speed as much as the ruggedness and the reliability. I need to make sure it will always work.”
|For example, computer processors and software are not cutting edge. With NASA’s input, Lockheed Martin selected the flight computer built by Honeywell International used on the Boeing 787 jetliner.|
“The one thing we really like about this computer is that it doesn’t get destroyed by radiation. It can be upset, but it won’t fail. We’ve done a lot of testing on the different parts in the computer. When it sees radiation, it might have to reset but it will come back up and work again. Since we’ll be going through a lot of radiation for quite a while, we’ve added another computer—a third—so if the two main computers go down because of radiation, this one will know the state of the vehicle if those two are lost. When the first two reset, they’ll go to the third and get the current data.”
The conical exterior back shell of Orion is covered with 970 ceramic-bonded low-density silica fiber tiles very similar to those designed for the Space Shuttle. Similar tiles were proven on 135 shuttle flights. These tiles are protected during launch ascent by a composite fairing assembly that is part of the overall Launch Abort System.
At first glance, Orion’s Launch Abort System (LAS) resembles that used on earlier Apollo missions, but that is where the comparison ends. At about one meter in diameter, it is significantly larger than the one used for the Apollo capsule. The LAS on the EFT-1 mission was inert, but a pad abort test was successfully conducted in 2010 that demonstrated the launch abort motor, attitude control motor, and the jettison motor. If ever needed, the LAS solid rocket abort motor will generate nearly 1.8 million newtons of thrust to remove Orion from the launch vehicle. A second and final abort system test will be conducted from Complex 46 using an Orbital Sciences-modified Peacekeeper motor to launch the same Orion capsule flown on EFT-1.
The heat shield, five meters in diameter, is built over a titanium skeleton and carbon fiber skin. Protecting this was a fiberglass-phenolic honeycomb with each of its 320,000 small hexagonal cells filled with a material called Avcoat. Much the same material and process was used for the Apollo capsule. Unlike the shuttle tiles, this heat shield is an ablative type that incrementally burns away as the capsule travels through the Earth’s atmosphere upon reentry.
Orion relies on proven parachute deployment to slow the capsule for an ocean landing, but such design, development, and testing of parachutes on a capsule, again, has not been conducted in more than four decades. At four hours and 19 minutes into the EFT-1 mission, Orion jettisoned its forward bay cover. Two drogue chutes deployed to begin slowing the capsule and aligned it for the subsequent deployment of three pilot parachutes used to pull the three massive main chutes from their compressed state. On EFT-1, the three main chutes deployed perfectly and Orion splashed down on target.
|To draw a down-to-Earth analogy, a race car built to compete in the 24 Hours of Le Mans is significantly different than one built to compete in a North America 500-mile event lasting only a few hours. The same is true of Orion vis-à-vis the Boeing CST-100 and SpaceX Dragon v2 capsules.|
Recovery operations for Orion differed markedly from those conducted for the returning Apollo capsules. Apollo capsules were removed from the ocean by a recovery ship crane and then placed on the deck for return to land. For Orion, NASA and Lockheed Martin employed the U.S. Navy’s amphibious ship, the USS Anchorage. After its landing in the Pacific Ocean, the capsule was secured and winched into the USS Anchorage’s flooded well deck at the rear of the ship. It was positioned over stabilizing shock absorbers, then the ocean water was drained from the well deck for the capsule to rest on the shock absorbers. The ship then returned to Naval Base San Diego.
There is a significant aspect to the Orion program that is often overlooked amidst the debate over its proposed missions, their expense, and the overall program’s distant timeline. America and its aerospace firms involved in the Orion program need to maintain and advance the technology that make human exploration of our solar system possible. As a spacefaring nation, the United States must demonstrate the ability to do so.
This has a tangible impact in the areas of research and development, the expansion of our knowledge base and the potential benefits that derive from this effort. Critics of the Orion and SLS programs argue that all this could be done for far less cost commercially. The success of NASA’s commercial cargo program has demonstrated this, although the commercial crew program has a few years to go before astronauts are once again launched from America. The fact is, the Orion program is far more commercial in its structure and operation that the shuttle program was, and NASA acknowledges this.
Nevertheless, Orion and its proposed missions beyond low-Earth orbit involve technology research and development that cannot currently be addressed by the SpaceX or Boeing commercial crew programs. To draw a down-to-Earth analogy, a race car built to compete in the 24 Hours of Le Mans is significantly different than one built to compete in a North America 500-mile event lasting only a few hours. The same is true of Orion vis-à-vis the Boeing CST-100 and SpaceX Dragon v2 capsules.
The technological significance of Orion is driven by three key requirements: the mitigation of long-term deep space radiation exposure to the crew, development of advanced upper stage propulsion to cut transit time to the mission destination (as well as deceleration during approach), and development of systems to replenish consumables.
The Wright brothers could not have conceived of the possibility of traveling at the speed of sound. So too, America’s true capability in human spaceflight should not be limited by what has been achieved in the past. As philosopher René Descartes once wrote, “There is nothing so far removed from us as to be beyond our reach, or so hidden that we cannot discover it.”