Jim Grossmann / NASA

At NASA's Kennedy Space Center in Florida, Lockheed Martin crews uncover the Orion ground test vehicle in the Launch Equipment Test Facility, or LETF.

By Jillian Scharr
Space.com

Since the space shuttle's retirement in 2011, NASA has relied on Russian rockets to launch its astronauts to space. But the United States plans to have its own homemade spacecraft again soon. Called the Orion Multipurpose Crew Vehicle, the new vehicle will be able to carry astronauts to Earth orbit, to the moon, asteroids and eventually to Mars.

Though it looks similar to the gumdrop shape of the Apollo moon-bound capsules, the Orion spacecraft is a whole new machine. Unlike the old capsules, Orion — set to make its first test flight in 2014 — can be reused.

The Orion capsule consists of three basic sections: a crew module, a service module, and a launch abort system. A powerful new rocket, called the Space Launch System, will be used to launch Orion into space. It's the crew module section, in particular, that can be recycled for multiple spaceflights. [Infographic: The Orion Capsule Explained]

No easy feat
Making a spacecraft reusable is not an easy feat.  Since the Apollo 11 first moon landing mission, many manned spacecraft have achieved a safe return to Earth by landing in the ocean.

Though ocean landings are easier from an engineering standpoint — the descending capsule doesn't need to slow down as much for a water impact, and there's no need for airbags or other cushioning devices — ocean landings are also expensive, as the salt water often ruins the spacecraft's electronics.

NASA

NASA's Orion spacecraft will carry astronauts further into space than ever before using a module based on Europe's Automated Transfer Vehicles (ATV).

A refurbishable Orion means the spacecraft will be cheaper to operate over the long term.

Lockheed Martin, NASA's lead contractor on the Orion project, originally looked into enabling the craft's crew module to set down on dry land by outfitting it with heavy drag parachutes, reverse thrusters, and airbags. But simulations revealed that the necessary equipment would add about 1,400 pounds (635 kilograms) of extra weight to the crew module, making the vessel far too heavy.  

So for the first few flights, at least, Orion's crew module will make water landings.

This poses a problem, as one of the ways Lockheed Martin is making Orion reusable is by placing the majority of its valuable electronics and computers in the crew capsule, the only part of Orion that returns to Earth. This design greatly reduces the amount of hardware and software that needs to be replaced for each flight, but it leaves the question — how to protect these valuable components from the corrosive effects of salt water?

Inside with the crew
Larry Price, Lockheed Martin's Orion deputy program manager, explained that Orion's design locates the majority of these electronics not only in the crew module, but within the pressurized section of the crew module in which the astronauts ride. This chamber is able to withstand the vacuum of space, and will also serve to keep out salty ocean water upon returning to Earth.

Equipment that has to be outside the pressurized section of the crew module, like exterior sensors or docking cameras, will be sealed to minimize damage from water as well as dust and micrometeoroids in space.

A major exception is the crew module's heat shield, which is designed to be consumed as the vessel re-enters Earth's atmosphere, thereby shielding the crew module from the heat of re-entry.

What's more, all of the Orion's component parts have been designed to be as generic as possible, so that between the craft's first test flight in 2014 and its projected Mars voyage in the 2030s, the spacecraft can be upgraded as new technologies become available.

"If the vehicle's designed to be viable for 30 years, you want to be able to upgrade these components when advances are made," Price said, explaining that if one component is upgraded — or discontinued — the whole system won't have to be redesigned.

While the crew module is designed to be almost entirely reusable, Orion's service module is a different story.

For Orion's first few flights, the service module will be detached just before the crew module re-enters the atmosphere, and is expected to burn up as it falls.

But further down the line, it may be possible to refurbish the service module as well. Price talked hypothetically about outfitting the service module with sensors so that it could stay in orbit as a satellite after detaching from the crew module. This way, it could be refilled with fuel for future missions in space. Then, future crew modules could be launched separately, to rendezvous with the service module outside the atmosphere.

This story was updated to correct the date of the first Orion test flight, which is planned for 2014, not 2017, as originally stated. The article was also updated to reflect the fact that many, but not most, crewed spacecraft have made landings in water.

Email jscharr@technewsdaily.com or follow her @JillScharr. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

• The Orion Space Capsule: NASA's Next Spaceship (Photos)
• 9 Things That Are Better Made in Space
• Photos: NASA's Space Exploration Vehicle for Asteroids & Beyond

Copyright 2013 Space.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

This story was originally published on Thu Jun 13, 2013 1:13 PM EDT

Science file

This is a view of the Great Sand Sea of Egypt from the Gilf Kebir Plateau in the Sahara desert.

By Becky Oskin
LiveScience

From lakes and grasslands with hippos and giraffes to a vast desert, North Africa's sudden geographical transformation 5,000 years ago was one of the planet's most dramatic climate shifts.

The transformation took place nearly simultaneously across the continent's northern half, a new study finds. The results will appear in an upcoming issue of the journal Earth and Planetary Science Letters.

The findings come from analyses of dust blown west from Africa and dropped into the Atlantic Ocean. Researchers sifted through 30,000 years of dust and ocean bottom muck retrieved with ocean drilling ships. The changing levels of windblown dust in the ocean sediments provide scientists with clues to Africa's climate and how it has changed over time. Simply put, a lot of dust means drier conditions and less dust means a wetter environment.

The wet period, called the African Humid Period, started and ended suddenly, confirming previous studies by other groups, the sediments revealed. However, toward the Humid Period's end about 6,000 years ago, the dust was at about 20 percent of today's level, far less dusty than previous estimates, the study found.

The study may give scientists a better understanding of how changing dust levels relate to climate by providing inputs for climate models, David McGee, an MIT paleoclimatologist and lead study author, said in a statement. Sahara desert dust dominates modern-day ocean sediments off the African coast, and it can travel in the atmosphere all the way to North America.

McGee and his colleagues are now testing whether the dust measurements can resolve a long-standing problem: the inability of climate models to reproduce the magnitude of wet conditions in North Africa 6,000 years ago.

Email Becky Oskin or follow her @beckyoskin. Follow us @OAPlanet, Facebook or Google+. Original article on LiveScience's OurAmazingPlanet.

• The 10 Driest Places on Earth
• Earth Quiz: Mysteries of the Blue Marble
• 50 Amazing Facts About Earth

Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

Georgia Institute of Technology / DOE

A map generated by Georgia Tech's tidal energy resource database shows mean current speed of tidal streams.

Next-generation technologies that harvest electricity from ocean waves and tides sloshing along the U.S. coasts could provide about 9 percent of the nation's demand by 2030, according to a pair of recent studies.

The findings, which include maps of these ocean energy resources, should help guide companies looking to develop them.

"We have believed for a long time that the resource was significant and these assessments add a tremendous level of confidence to what that potential is," Mike Reed, water power team lead with the U.S. Department of Energy's Wind and Water Program told me Monday. 

Today, about 6 percent of the nation's electricity comes from traditional hydropower projects, such as the Grand Coulee Dam, that direct the flow of the river through turbines to generate power.

Since such dams plug up rivers and make it difficult for migrating fish species such as salmon to reach their spawning grounds, they have lost favor in recent years. 

Looking forward, energy developers see promise in technologies that capture the energy in waves and tides off the coasts. 

Designs to do this range from buoys that harness the up-and-down motion of passing waves to turbines on the ocean floor that are spun by the ebb and flow of the tides.

The studies released earlier this month from the U.S. Department of Energy could help nudge along the development and deployment of these technologies by showing the resource is there to be captured.

Motion of the ocean
The U.S. uses about 4,000 terawatt hours of electricity per year. The maximum theoretical electric generation that could be produced from waves and tides is approximately 1,420 terawatt hours per year, the assessments found.

"We are never suggesting that all of that would be captured," Hoyt Battey, team lead for water power market acceleration and deployment with the DOE Wind and Water Program, told me. 

But based on the resource assessments and current understanding of what it will take to scale up and deploy the technology, wave and tidal power could be upwards of 9 percent by 2030.

The DOE has set a goal that water power, including traditional hydroelectricity, total 15 percent of the nation's supply by 2030.

To measure the wave resource, the DOE worked with the Electric Power Research Institute and Virginia Tech to develop a model that accurately predicted past wave regimes and used it to predict future wave climate.

Those predictions are converted into wave power densities. As surfers know, waves from one day to the next are not the same, but they know what beaches tend to have the best waves when conditions are right, Reed noted.

Like surfers trying to figure out where and when to vacation, utility owners and operators can use the new resource data to figure out where the best reliable waves are to put their converters.

This knowledge, combined with reliable forecasts out several days on wave heights, will allow utilities to balance their loads with other sources such as a natural gas fired power plant.

"Wave energy is predictable and forecastable," he said. "If you are a utility operator or utility owner, that predictability adds value."

Tides are even more predictable, noted Battey. "You know down to the second years ahead of time what the tidal regime will be," he said.

The tidal resource maps were created by researchers at Georgia Tech and are available online.

Realizing the potential
Resource assessments such as these, as well as others mapping potential geothermal, solar and wind resources, can nudge development of green energy technologies.

But a key word in such assessments is "potential." As long as generating electricity from coal, oil, and natural gas remains cheap and politically salable, wave and tidal resources will struggle to compete.

Reed takes the long view. Although wave and tidal energy projects today are expensive, he said, their costs should fall as the technology is improved and scaled up over the next few decades.

"A good comparison would be to go back 15 to 20 years in the wind and solar industry and see how their costs have dramatically come down," he said.

While wind and solar still struggle to compete with traditional sources today, the falling prices of the technologies and abundance of the resources are beginning to make them attractive.

Given the size of the wave and tidal resource identified, Reed said there's plenty of room for wave and tidal energy developers to get their feet wet and begin to drive down costs.

More on wave and tidal energy:

• $28 billion in wave energy projects proposed
• IBM sees energy, money in motion of the ocean
• Here's an idea: Floating webs that capture sun, wave power
• Oregon coast could be wave energy hub
• Maine offers testbed for power from tides