By the time Space Shuttle Atlantis touched down after its final voyage in July 2011, bringing an end to NASA's 30-year-long space shuttle program, a major shift in the nation's strategy for space exploration was already underway. NASA's new plan involves using the fast-developing, private space-launch industry to carry out the low-orbital missions the space shuttles once performed. That approach will allow the U.S. space program to concentrate its efforts and funding on longer-range manned missions and unmanned probes that will venture deeper into the solar system.
In a 2011 speech, NASA Administrator Charles Bolden sketched out some of the details, including the agency's new Space Launch System, a launch vehicle similar to the Apollo's Saturn V booster that'll be the most massive rocket ever built, and the Multi-Purpose Crew Vehicle, a manned spacecraft capable of transporting four astronauts for space missions of up to three weeks in length. In addition to those programs, NASA also plans on a number of other robotic missions, including a quest to find evidence of conditions that would support microbial life on Mars [source: NASA].
What else is up NASA's sleeve? Here's a rundown of five of the more interesting new NASA forays into the cosmos.
When the Spirit and Opportunity rovers landed on Mars in 2004, it was one of the most phenomenally successful space exploration missions ever [source: NASA]. The twin robots survived for years beyond their expected lifespan and gathered a treasure trove of knowledge, including evidence that liquid water may have existed fairly recently on the planet's surface [source: NASA]. Scientists hope that the Curiosity robotic rover, which is scheduled for launch in late November to mid-December 2011, will follow in its predecessors' illustrious tread marks.
At 10 feet (3 meters) in length, Curiosity is twice as big as the previous rovers, and it carries the most extensive array of scientific instruments ever sent to explore another planet's surface. Powered by an on-board nuclear generator, the six-wheeled robot is designed to roam between an eighth and a quarter of a mile each day. Its super-high resolution camera, which is capable of capturing details smaller than the width of a human hair, will take extreme close-up photos of rocks, soil and -- if it exists -- ice on the Martian surface. Another instrument, the ChemCam, will aim a laser beam at Martian rocks and turn them into hot gas, which then can be analyzed by other instruments to determine the rocks' chemical composition down to the atomic level. The rover's most important scientific mission is to search for conditions in which microbial life might possibly exist, but it will also measure radiation levels on Mars, a prerequisite for an eventual manned mission [source: NASA].
In August 2011, less than a month after the final shuttle flight touched down, NASA launched Juno, a robotic probe that will venture vastly farther than any human astronaut has ever gone. Named after the Roman goddess who was Jupiter's spouse, the 11-foot-by-11-foot (3.3-meter-by-3.3-meter) spacecraft will circle the solar system's biggest planet, following a polar orbit designed to avoid its high-radiation regions.
While other spacecraft have transmitted glimpses of Jupiter, Juno is the first that'll be able to "see" 30 to 45 miles (48.2 to 72.4 kilometers) through the planet's dense cloud cover with its infrared camera. Other instruments will map Jupiter's magnetic and gravitational fields and use microwave radiation to provide data on the structure, chemical composition and movement of Jovian clouds. To take in the optimal amount of data, Juno is designed to rotate twice each minute as it orbits, allowing its instruments to sweep the field of view. The probe's main purpose is to learn more about how the giant planet formed and evolved, knowledge that will help scientists understand giant planets being discovered around other stars [source: NASA].
While the dream of another manned mission to the moon seems to be on hold for a while, there's still plenty that we don't know about Earth's satellite, particularly about its interior and its natural history, which might give us a better understanding of the solar system's formation. But scientists are hopeful that the twin GRAIL orbital probes, launched in September 2011 and scheduled to orbit the moon for several months starting in December 2011, will shed light on some of the moon's mysteries by creating a high-resolution map of the variations in its gravitational field.
The twin satellites, each about the size of a washing machine, will circle the moon together in a polar orbit, which means they'll fly over the moon's north and south poles, rather than around the moon's equator. The two satellites are designed to fly in tandem in an exact alignment. But as they pass over any feature on the moon's surface -- such as a mountain or crater, or an underground deposit of minerals -- that's big enough to cause a variation in the lunar gravitational field, that change in gravitational pull will slightly alter the position of the satellites in relation to each other. When that happens, super-sensitive instruments will measure the difference, down to a few microns -- the diameter of a red blood cell. That data will enable scientists to draw an extremely precise gravitational field map. Each spacecraft also will carry a set of cameras that will send images to NASA's MoonKAM educational Web site, where they can be viewed by teachers and students [source: NASA].
In February 2012, the NuSTAR orbital observatory is scheduled to be launched into orbit in a path near the equator at about 300 miles (483 kilometers) in altitude (in space exploration lingo, a low-Earth orbit). It will be equipped with telescopes capable of focusing on X-ray radiation from distant stars, and will be able to transmit images that are 10 to 100 times more detailed than images from previous orbital telescopes. During its two-year main mission, NuSTAR will survey regions around the center of the Milky Way, searching for dying stars and black holes [source: Caltech]. The latter are the burned-out remnants of once-giant suns whose immense mass has collapsed to form bizarre points of zero volume and infinite density, with gravity so powerful that not even light can escape [source: NASA]. In addition, NuSTAR will study the mysterious streams of particles that gush out of supermassive black holes. It also will examine the chemical remnants of exploded stars, to shed light on how stars explode and create elements in the process [source: Caltech].
NASA originally planned to follow the space shuttle program with Constellation, a $97 billion effort whose main purpose was to be a return visit to the moon in 2020. However, the program was cancelled in 2010 by the Obama administration after escalating cost overruns and delays raised doubts that Constellation could achieve its goal. But even though increasingly money-conscious NASA plans to outsource some of the missions in low-Earth orbit that once were the shuttle's bread and butter, we shouldn't assume that the U.S. space program is done thinking big.
To the contrary, in September 2011, NASA unveiled the design for its new Space Launch System (SLS), a gargantuan two-stage rocket whose five engines will produce as much as 9 million pounds (4 million kilograms) of thrust when lifting off from the launch pad, even more than the towering Saturn V that was the mainstay of the Apollo program. And when SLS is ready for launch in 2017, each flight will be able to hoist 286,000 pounds (129,727 kilograms) of payload into space, nearly six times what the shuttle could carry in its cargo hold, for about the same $3 billion annual cost [source: Harwood]. The agency plans to use SLS to launch the Orion spacecraft, which can support four astronauts for trips of three weeks or even longer, and is capable of venturing deeper into space than the shuttle could. (Orion originally was envisioned as the spacecraft for the now-cancelled 2020 return to the moon.) When welders started working on an Orion capsule in New Orleans in September 2011, it marked the first time that a manned spacecraft had been built in the United States since space shuttle Endeavor left the factory in 1991 [source: NASA].
Why are missions like Cassini important? Learn more about the Cassini mission in this HowStuffWorks article.
More Great Links
- "About NuSTAR: The Nuclear Spectroscopic Telescopic Array." Caltech.edu. (Sept. 19, 2011) http://www.nustar.caltech.edu/about-nustar
- "GRAIL: Gravity Recovery and Interior Laboratory." Nasa.gov. July 12, 2011. (Sept. 19, 2011) http://www.nasa.gov/mission_pages/grail/overview/index.html
- Harwood, William. "NASA Picks Orion-type Capsule for Deep Space Missions." CNET.com. May 24, 2011. (Sept. 21, 2011) http://news.cnet.com/8301-19514_3-20065857-239/nasa-picks-orion-type-capsule-for-deep-space-missions/
- Harwood, William. "NASA Unveils New Super Rocket for Manned Flights Beyond Earth Orbit." CBS News. Sept. 14, 2011. (Sept. 19, 2011) http://www.cbsnews.com/network/news/space/home/spacenews/files/8ef7f2e7f3ddec1c1a67085fd26c335b-336.html
- "Mars Science Laboratory." Jpl.nasa.gov. April 2011. (Sept. 19, 2011) http://marsprogram.jpl.nasa.gov/msl/news/pdfs/MSL_Fact_Sheet.pdf
- Matson, John. "Phased Out: Obama's NASA Budget Would Cancel Constellation Moon Program, Privatize Manned Launches." Scientific American. Feb. 1, 2010. (Sept. 19, 2011) http://www.scientificamerican.com/article.cfm?id=nasa-budget-constellation-cancel
- Matthews, Mark. "NASA's Post-shuttle Plan Draws Criticism." Los Angeles Times. May 12, 2011. (Sept. 19, 2011) http://articles.latimes.com/2011/may/12/nation/la-na-recycled-shuttle-rocket-20110512 .
- "Modified Record of Decision for NASA's Post-Shuttle Human Spaceflight Program and the Constellation Programmatic Environmental Impact Statement." NASA Exploration System Missions Directorate. June 2011. (Sept. 19, 2011) http://www.nasa.gov/pdf/576209main_CxP%20ROD%20wSignatures%207-29-11.pdf
- "NASA Facts: Mars Exploration Rover." Marsrover.nasa.gov. April 20, 2010. (Sept. 19, 2011) http://marsrover.nasa.gov/newsroom/factsheets/pdfs/Mars03Rover041020.pdf
- "Orion: America's Next Generation Spacecraft." NASA. 2010. (Sept. 19, 2011)
- "Orion MPCV." Nasa.gov. Sept. 19, 2011. (Sept. 19, 2011) http://www.nasa.gov/exploration/systems/mpcv/firstweld.html
- "Solar System Exporation: Juno." Jpl.nasa.gov. Aug. 8, 2011. (Sept. 19, 2011) http://sse.jpl.nasa.gov/missions/profile.cfm?MCode=Juno&Display=ReadMore
- Sauser, Brittany. "What are NASA's Post-Shuttle Plans?" Technology Review. July 8, 2011. (Sept. 19, 2011) http://www.technologyreview.com/blog/deltav/26980/