Lockheed Martin Pressing To Simplify Orion Heat Shield
ARLINGTON, Va. — Lockheed Martin Space Systems will spend March 4 debriefing NASA on the first test flight of the Orion deep-space crew capsule, with an eye toward selling the agency on a redesign of the craft’s all-important heat shield, a senior company official said here Feb. 18.
Mike Hawes, Orion vice president and program manager at Denver-based Lockheed Martin Space Systems, said data from the four-and-a-half hour Exploration Flight Test (EFT)-1, carried out Dec. 5 indicates that a lower-cost heat shield design could provide the necessary protection for Orion crews.
In the EFT-1 mission, an uncrewed Orion launched aboard a United Launch Alliance Delta 4 rocket from Cape Canaveral Air Force Station in Florida, reached a peak altitude of 5,800 kilometers during two Earth orbits, and re-entered the atmosphere at about 80 percent of the speed it would achieve during a return from lunar space. Orion will venture to lunar space in 2018 in another uncrewed test flight, and repeat the mission with a crew in 2021.
Temperatures on re-entry “were lower than we expected” on EFT-1, Hawes told reporters here during Lockheed Martin’s annual media day.
That data supports a Lockheed Martin proposal to scrap the current heat-shield design, which features a 5-meter-diameter honeycombed frame, in favor of an alternative composed of rectangular heat-resistant tiles glued together with a silicone-based adhesive, Hawes said.
Such a change, Hawes said, could shave hours — and therefore dollars — off the heat shield manufacturing process currently employed by subcontractor Textron, which is based in Boston.
“That’s one of our bigger concerns with the heat shield, just the long-term manufacturing. [We want] something that would be less touch-intensive,” said Hawes, who joined Lockheed in 2011 after a 30-year NASA career.
The current process requires Textron technicians to inject insulating material into thumbnail-wide holes in the honeycombed frame using a caulking gun, Hawes said. The shield must then be cured in an oven and sanded down, an arduous and time-consuming process.
Replacing the honeycomb structure with plates that can be glued together with a silicone sealant that bonds at room temperature would be easier, cheaper and no less safe, Hawes said.
Lockheed Martin’s Orion contract, signed in 2006, is now worth about $12 billion. The deal covers only the first three capsules, only the last of which would carry a crew.
Hawes said Lockheed has already sent NASA a 600-megabyte preliminary report on EFT-1, which by all accounts was a success.
One of the few blemishes on the flight was the failure of two of Orion’s five so-called uprighting bags to fully inflate after the capsule splashed down some 1,015 kilometers southwest of San Diego. The bags are designed to prevent Orion from tipping top-down in the ocean.
One of the balky bags did not inflate at all; the other partially inflated. Preliminary data indicates that the bags themselves, and not the plumbing that pumps them full of gas, were to blame, Hawes said. Whether the bags were punctured somehow during flight, or their material is defective, Lockheed still is not sure.
Orion’s electronics, meanwhile, appear to have survived their trips through Earth’s high-radiation Van Allen belts during EFT-1, Hawes said. Orion is likely to pass through the Van Allen belts on its way to and from deep-space destinations.
There was a momentary electrical hiccup, Hawes acknowledged, but it does not appear to be tied to trans-Van Allen passage.
“We did see some restarts of the video processing units [aboard Orion], but right now the data doesn’t look like it was driven by the Van Allen belts,” said Hawes. “We can see that the avionics data tells us that we have passed through the high-radiation source, but it looks like the behavior was actually very crisp going through that.”