Posts Tagged ‘nasa’
NASA’s Falling UARS Satellite Found in Remote South Pacific
Maybe next time, Canada
See our gallery of the space race's greatest falls to Earth. (List compiled by .)
NASA has been tracking UARS for some time now as the decommissioned satellite’s orbit has been decaying. Much of the satellite was expected to burn up on re-entry, but experts estimated that roughly two-dozen pieces of the massive satellite would survive and could potentially be a threat to people or objects on the ground. Given UARS’s speed and the many variables involved (this is a decommissioned satellite, after all, so re-entry was completely uncontrolled) there was no telling exactly when or where UARS might land.
On Saturday, when the final descent began, previous calculations had placed the crash window across a large swath of northwestern North America. The Internet rumor machine fired up and sightings across Canada and the Pacific Northwest proliferated. But by that point updated U.S. Air Force calculations placed the satellite thousands of miles away in another hemisphere, and NASA has confirmed those calculations. UARS is now resting peacefully in the South Pacific, somewhere southwest of Christmas Island were small islands are scattered across a lot of water.
The difference between Seattle and Samoa? Just a few minutes. NASA said UARS came in for its rough landing several minutes earlier than they had projected. What they won’t say is how they know this--they referred those questions to the USAF, which also isn’t talking. Were DoD missile tracking assets employed in tracking UARS? The Air Force would rather not say at this point, but one would think something like this would be good practice.
UARS is to come crashing back to Earth, and it won’t be the last. In late October or early November a German astronomy satellite will make its uncontrolled final plunge back to Earth. Though smaller than UARS, more pieces are expected to survive re-entry (a total of 30 are expected, possibly including sharp pieces of mirror). Let’s hope that one finds a nice stretch of uninhabited ocean as well.
[]
Congress Preserves James Webb Telescope For Now, But At What Cost?
Budget writers in the Senate said last week the telescope will continue being built, which is much better than the news we heard in July, when a . Budget debates (and astronomers’ outrage) ensued, and in this latest version, NASA gets $1 billion more and the telescope is preserved.
last week indicated the telescope would be funded, but it wasn’t clear where the money originated; now it’s clear it comes out of NASA’s science budget. The Senate Approps’ Subcommittee on Commerce, Justice, Science and Related Agencies explains it thusly:
“NASA has never requested adequate resources to fund [JWST’s] development. As with many other projects, budget optimism led to massive ongoing cost overruns because the project did not have adequate reserves or contingency to address the kinds of technical problems that are expected to arise in a complex, cutting edge project.”
The report, issued Friday, is online . So now NASA will get $529.6 million for JWST, up from the initial $354.6 million the space agency requested. This is a direct response to a congressional report we told you about last fall, in which auditors from NASA and independent groups decried the mission's .
All this will likely mean negative consequences for other missions, however. NASA’s heliophysics, planetary science and Earth science divisions will all have to bear some of the JWST cost burden, thereby pitting scientists against scientists. Is infrared astronomy worth the astronomical price tag? It will be interesting to see how this plays out as Congress finishes the budget this fall. (It’s supposed to be completed by Sept. 30, but there’s no chance of that — the House has already introduced a continuing resolution, which funds everything at 2011 levels through Nov. 18).
Also, bear in mind that this is by no means over. Both chambers must agree on funding levels, and with a $1 billion gap between the House and Senate, it's a fair bet that the JWST debate isn't done yet.
Meanwhile, the telescope’s mirrors are done, and engineers at have started testing the Mylar coating that will shield the infrared telescope from the sun’s warmth. Read more of PopSci’s JWST coverage .
Meet NASA’s New Deep Space Rocket
The Space Launch System will be the next NASA-administered launch vehicle to take humans into Earth orbit and beyond
Resembling the Saturn V in both format and capabilities, the SLS is based around technology developed and honed in the Space Shuttle program. Its core stage rockets are the same RS-25 the shuttle used for main engines, and its strap-on solid rocket boosters are also similar to those used on the shuttle; these solid boosters will be used for initial flights, but NASA hopes to develop cheaper liquid-fueled detachable boosters for later missions. The J-2X engine used in the upper stage is similar to one developed by Rocketdyne for the Saturn V.
The SLS's payload capacity will range from 70 to 130 metric tons, depending on launch configurations, making it the most powerful launch system since the Saturn V. By utilizing different combinations of the core, upper and booster stages, NASA will be able to efficiently adapt the SLS to a variety of mission types.
And of course, the SLS will carry the Orion multi-use crew capsule, an offshoot from the now-defunct Constellation project. It is capable of carrying a crew of four to six astronauts.
NASA released a computer animation of the new SLS taking to the skies:
brightcove.createExperiences();
A Supernova Fades Gloriously into a Supernova Remnant
The supernova debris has been dimming in the years since its discovery, but a team of astronomers announced today that the debris is now beginning to brighten again. This means that it is being lit by a different power source, and is a sign of 1987a's transition from supernova to supernova remnant.
When a supernova forms, most of its light comes from the radioactive decay of elements created in the explosion, which decreases and fades over time. As you can see in the image above, 1987a is surrounded by a ring of detritus that flew off the progenitor star before it exploded. Inside the ring, the fish-shaped cloud of star guts is expanding ever outward. Some of this material is starting to hit the surrounding ring, which is creating shock waves that produce X-rays. These X-rays, combined with shock heating, are the new power source that is causing the supernova remnant to brighten.
When the rest of the expanding stellar debris hits, the ring will shred and little of the former star's history will remain. Until then, scientists can study the last several thousand years of the stars life by observing the swirls of gas and interstellar stuff.
GRAIL Mission Is On Its Way to the Moon
Read our full coverage of the mission .
After Weather Delay, Grail Moon Mission Now Set to Launch Saturday
Strong winds in the upper atmosphere forced NASA to scrub Thursday's planned launch of its . The Gravity Recovery and Interior Laboratory is now set to lift off at 8:33 a.m. EDT or 9:12 a.m. PDT Saturday — but the weather is still not cooperating.
There's about a of favorable conditions for Saturday, the same initial forecast for Thursday, the space agency said. Upper level winds were in violation of the launch criteria and must calm down before NASA will send a rocket through them.
Grail is designed to study the gravity field and interior composition of the moon. Twin probes will fly in formation, monitoring tiny changes in the distance between then to discern the moon's gravitational field.
They will take several months to arrive at the moon, ensuring they burn as much fuel as possible before arrival.
NASA Heads Back to the Moon, to Uncover Its Origins and to Inspire A New Generation
The GRAIL mission launches this week
GRAIL A and its twin GRAIL B are set to launch Thursday morning aboard a Delta II rocket from Cape Canaveral Air Force Station. The launch window opens at 8:37 a.m. EDT, although weather looks pretty iffy for the next couple days, according to NASA. Once they arrive at the moon, the two washing machine-sized probes will fly in formation, with instruments sensitive enough to detect a hair’s breadth separation. Along with those gravity-mapping instruments, GRAIL will carry something called MoonKAM — “Moon Knowledge Acquired by Middle school students.”
Logging in from schools around the country, students will be able to virtually coast a few miles above the surface of the moon, scanning the pallid dirt for craters or perhaps an open plain that might someday make a . Students can select target areas by studying topographic maps on the , and send them to NASA’s MoonKAM operations center. The images will be fairly high-resolution, but they won’t approach the abilities of the Lunar Reconnaissance Orbiter, which took the snapshots we saw this week of . But that’s not the point, said Maria Zuber, a professor of geophysics at MIT and the mission’s lead investigator.
“If a student takes an image of the surface, it’s really a transformative experience. You can bet that a smart kid will take the time to sit down and figure out how to use this software,” she said in an interview.
Each spacecraft will carry a digital camera setup with four camera heads, one pointed ahead, two pointed below and one pointed behind the spacecraft’s trajectory. They can capture video and still images up to 30 fps, and downlink them to the project’s control center at the University of California-San Diego. The program is a partnership with Sally Ride Science, a company founded by Ride, the first American woman in space.
Zuber and the other mission scientists, many of whom have kids and grandkids, hope the moon images will inspire a new generation of lunar scientists — who will understand, as they have, that the history of the moon is crucial for understanding the history of Earth.
With its perennially unchanging mountains and craters, the moon is a good proxy for the early Earth, Zuber said. Understanding how it formed could shed some light on the geologic processes behind Earth’s formation, and that of the other terrestrial planets. Just last month, researchers from the University of California-Santa Cruz said the moon may have once had a after a collision. Grail will shed some light on this question, as well as explain whether the moon has a molten core, which will provide some more information about how it coalesced.
Zuber said Grail will solve a few pieces of the larger lunar puzzle.
“If you think about your family and friends and the people you know best, if you just see what they’re like on the outside, you don’t really know them,” she said. “If you really want to know them, you want to understand what’s inside of them, and that tells you what they’re all about.”
Grail has several unique characteristics that will help it pull this off. The spacecraft are based on a classified military satellite called XSS-11, built to demonstrate satellite rendezvous maneuvers, which helped mission planners design a system that could work well in tandem. Its avionics are modeled after the Mars Reconnaissance Orbiter, a successful mapping mission that is still sending back data. Previous gravity mapping missions, including the Gravity Recovery And Climate Experiment, also helped inform some of the project's goals, Zuber said.
Grail’s instruments are sensitive enough to measure changes of a few tenths of a micron every second, infinitesimally small differences that result from changing topographic features. But such small differences can also be caused by other phenomena, like solar wind and fuel sloshing around in the spacecraft’s tanks, for instance. Grail scientists had to account for that, too, so they are sending Grail A and B on a lengthy, circuitous course so they burn as much fuel as possible before entering orbit.
The probes will arrive at the moon as 2012 dawns, with one arriving Dec. 31 and one arriving Jan. 1. They will spend about two months synchronizing their orbits, and once everything is in alignment, the probes will spend three months making their gravity measurements. The whole mission will be done by next June, Zuber said. The spacecraft will crash into the lunar surface shortly thereafter — but not before sending photos back to schoolchildren.
Although the main mission is to map the moon’s gravity field, Grail will accomplish much more than that, Zuber said.
“It’s very hard to get a gravity mission funded. You definitely have to have the big picture in mind,” Zuber said. And for NASA, that can mean much more than just science.