NASA’s orbital spacecraft Dawn has sent the closest images of the dwarf planet called Ceres. The stunning pictures display Ceres’ cater formation features with tall conical mountains and narrow braided fractures on it.
“Dawn’s view is now three times sharper than its previous mapping orbit, revealing exciting new details of this intriguing dwarf planet,” said Marc Rayman, Dawn’s chief engineer and mission director at NASA’s Jet Propulsion Laboratory in California.
At its current orbital altitude of 1,470 km, Dawn takes 11 days to capture and return images of Ceres’ whole surface. Over the next two months, the spacecraft will map the entirety of Ceres six times. The spacecraft is using its framing camera to extensively map the surface, enabling 3-D modelling. Every image from this orbit has a resolution of 450 feet per pixel, and covers less than one percent of the surface of Ceres.
At the same time, Dawn’s visible and infra-red mapping spectrometer is collecting data that will give scientists a better understanding of the minerals found on Ceres’ surface. Engineers and scientists will now refine their measurements of Ceres’ gravity field which will help mission planners in designing Dawn’s next orbit.
Dawn is the first spacecraft to visit a dwarf planet, and also the first to orbit two distinct solar system targets. In late October, Dawn will begin spiralling toward the final orbit, which will be at an altitude of 375 km.
Washington, October 12, 2017 : The shortage of plutonium threatens NASA’s future mission to explore deep space, the US government has warned.
The break in production of plutonium 238 (Pu-238) between 1988 and 2015 could result in a bottleneck situation, where there is not enough of this scarce resource to power spacecraft during long-duration missions, Newsweek.com reported this week citing a government report.
NASA has long used radioisotope power systems (RPS) to generate reliable electrical power and heat energy for long-duration space missions, the US Government Accountability Office (GAO) report said.
But given NASA’s current plans for solar system exploration, the supply of this critical resource could be exhausted within the next decade, putting in jeopardy its future missions that would require this fuel, it warned.
RPS can operate where solar panels or batteries would be ineffective or impossible to use, such as in deep space or in shadowed craters, by converting heat from the natural radioactive decay of plutonium-238 (Pu-238) into electricity.
Missions such as Mars Curiousity rover and the Voyager 1 and 2 spacecraft use radioisotope thermoelectric generators as power source.
The production problems of Pu-238 and subsequent risks to NASA have been known for several years.
The Department of Energy (DOE) and its predecessor agencies have been providing Pu-238 and fabricating RPS for NASA and other federal agencies for more than five decades decades
DOE currently maintains about 35 kgs of Pu-238 isotope designated for NASA missions, about half of which currently meets the power specifications for spaceflight.
However, given NASA’s current plans for solar system exploration, this supply could be exhausted within the next 10 years.
Specifically, NASA plans to use about 3.5 kg of Pu-238 isotope for one RPS to power the Mars 2020 mission, the Government Accountability Office report said.
NASA may also use an additional 10.5 kg of Pu-238 isotope for its New Frontiers #4 mission if three RPS are used.
If DOE’s existing Pu-238 supply is used for these two missions, NASA would be forced to eliminate or delay future missions requiring RPS until DOE produces or acquires more Pu-238, the report said. (IANS)
Cape Canaveral, Sep 23, 2017:NASA’s asteroid-chasing spacecraft is swinging by Earth on its way to a space rock.
Launched a year ago, Osiris-Rex will pass within about 11,000 miles (17,700 kilometers) of the home planet Friday afternoon. It will use Earth’s gravity as a slingshot to put it on a path toward the asteroid Bennu.
If all goes well, Osiris-Rex should reach the small, roundish asteroid next year and, in 2020, collect some of its gravel for return to Earth.
Friday’s close approach will occur over Antarctica. It will be a quick hello: The spacecraft will speed by at about 19,000 mph (31,000 kph). NASA has taken precautions to ensure Osiris-Rex does not slam into any satellites. Ground telescopes, meanwhile, have been trying to observe the spacecraft while it’s in the neighborhood.
The asteroid is called Didymos — Greek for “twin” — because it is an asteroid binary system that consists of two bodies
The target for the first-ever mission to demonstrate an asteroid deflection technique for planetary defense — the Double Asteroid Redirection Test (DART)
DART would fly to Didymos, and use an on-board autonomous targeting system to aim itself at Didymos B
July 10, 2017: Aiming to show how to protect Earth from a future killer asteroid strike, NASA plans to crash a refrigerator-sized spacecraft at a speed about nine times faster than a bullet into a space rock, forcing it to change its orbit.
The target for the first-ever mission to demonstrate an asteroid deflection technique for planetary defense — the Double Asteroid Redirection Test (DART) — is an asteroid that will have a distant approach to Earth in October 2022, and then again in 2024, NASA said.
“DART would be NASA’s first mission to demonstrate what’s known as the kinetic impactor technique — striking the asteroid to shift its orbit — to defend against a potential future asteroid impact,” said Lindley Johnson, planetary defence officer at NASA Headquarters in Washington.
The asteroid is called Didymos — Greek for “twin” — because it is an asteroid binary system that consists of two bodies — Didymos A, about 780 metres in size, and a smaller asteroid orbiting it called Didymos B, about 160 metres in size.
DART, scheduled for launch in 2020, would impact only the smaller of the two bodies, Didymos B.
The Didymos system has been closely studied since 2003. The primary body is a rocky S-type object, with the composition similar to that of many asteroids.
The composition of its small companion, Didymos B, is unknown, but the size is typical of asteroids that could potentially create regional effects should they impact Earth.
“A binary asteroid is the perfect natural laboratory for this test,” said Tom Statler, program scientist for DART at NASA Headquarters.
“The fact that Didymos B is in orbit around Didymos A makes it easier to see the results of the impact, and ensures that the experiment doesn’t change the orbit of the pair around the sun,” Statler added.
After launch, DART would fly to Didymos, and use an on-board autonomous targeting system to aim itself at Didymos B.
Then the spacecraft would strike the smaller body at a speed about nine times faster than a bullet, approximately six kilometres per second.
Earth-based observatories would be able to see the impact and the resulting change in the orbit of Didymos B around Didymos A, allowing scientists to better determine the capabilities of kinetic impact as an asteroid mitigation strategy.
The kinetic impact technique works by changing the speed of a threatening asteroid by a small fraction of its total velocity, but by doing it well before the predicted impact so that this small nudge will add up over time to a big shift of the asteroid’s path away from Earth.
“DART is a critical step in demonstrating we can protect our planet from a future asteroid impact,” saiid Andy Cheng of The Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, the DART investigation co-lead. (IANS)