Thirdly, the AES division has selected a Near Earth Asteroid (NEA) scout mission to accompany SLS on her maiden voyage in order to investigate environmental elements surrounding an NEA.
Specifically, the NEA scout mission is tasked with determining the
size, rotational state, surface properties, and interaction environment
of an NEA.
This will be accomplished via a flyby or rendezvous with and
characterization of an NEA that is “representative of a potential human
mission target,” notes the AES presentation.
[…]
Specifically, the NEA scout will have an 85 square meter solar sail
which will allow it to target an NEA within 1 AU (Astronomical Unit –
average one-orbit distance between the Sun and the Earth) of Earth.
NASA selected Aerojet Rocketdyne of Sacramento, California, to
restart production of the RS-25 engine for the agency’s Space Launch
System (SLS), the most powerful rocket in the world, and deliver a
certified engine. SLS will use four RS-25 engines to carry the agency’s
Orion spacecraft and launch explorers on deep space missions, including
to an asteroid placed in lunar orbit and ultimately to Mars.Part of NASA’s strategy to minimize costs of developing the SLS
rocket was to leverage the assets, capabilities, and experience of the
Space Shuttle Program, so the first four missions will be flown using 16
existing shuttle engines that have been upgraded.Under the $1.16 billion contract, Aerojet Rocketdyne will modernize
the space shuttle heritage engine to make it more affordable and
expendable for SLS. The contract runs November 2015 and continues
through Sept. 30, 2024.
NASA has awarded contracts to three American propulsion companies to
aid the U.S. federal space agency with the development of advanced
deep-space Electric Propulsion systems – including VASIMR – needed to
one day transport astronauts to destinations beyond Low Earth Orbit
(LEO).
As part of NASA’s phased approach to the development of technology and systems needed to carry astronauts on long-duration, deep-space missions,
the agency’s Human Exploration Operations Mission Directorate’s
(HEOMD’s) Advanced Exploration Systems (AES) division has committed to
the “rapid development and testing of prototype systems and validation
of operational concepts to reduce risk and cost of future exploration
missions.”
Part of this initiative includes the development of systems that will aid in the human and robotic exploration of Beyond Earth Orbit targets.
To do so, however, requires new propulsion systems that have
previously been unnecessary for Near Earth Orbit exploration – where
traditional chemical-based propulsion works best toward the short
duration and relative close proximity of missions and their
destinations.
A new paper from Massimo Marengo (Iowa State) and colleagues looks at
what Tabetha Boyajian identified as the most likely natural cause of the
KIC 8462 light curves. All I have at this point is the JPL news release and a release
from Iowa State — the paper has not yet appeared online — describing
evidence for a swarm of comets as the culprit. The study, which has been
accepted at Astrophysical Journal Letters relies on Spitzer data dating from 2015, five years later than the WISE data that found no signs of an infrared excess.
If there had been a collision between planets or asteroids in this
system, it was possible that the WISE (Wide-field Infrared Survey
Explorer) data, taken in 2010, reflected conditions just before the
collision occurred. Now, however, we can rule that out, because Spitzer,
like WISE, finds no excess of infrared light from warm dust around KIC
8462. So the idea of planet or asteroid collisions seems even less
likely. Marengo, according to the JPL document, falls back on the idea
of a family of comets on an eccentric orbit.
[…]
It would take a very large comet indeed to account for the drop in flux
we’ve already seen, but a swarm of comets and fragments can’t be ruled
out because we just don’t have enough data to make the call. I assume
Marengo also gets into the fact that a nearby M-dwarf (less than 900 AU
from KIC 8462, is a possible influence in disrupting the system. The
comet explanation would be striking if confirmed because we have no
other instances of transiting events like these, and we would have found
these comets by just happening to see them at the right time in their
presumably long and eccentric orbit around the star.
So, despite PR headlines like Strange Star Likely Swarmed by Comets,
I think we have to take a more cautious view. We’re dealing with a
curious star whose changes in flux we don’t yet understand, and we have
candidate theories to explain them. We’re no more ready to declare
comets the cause of KIC 8462’s anomalies than we are to confirm alien
megastructures. At this point we should leave both natural and
artificial causes in the mix and recognize how long it’s going to take
to work out a viable solution through careful, unbiased analysis.
Washington and Beijing have established an emergency “space hotline” to reduce the risk of accidental conflict.
As fears grow of an orbital arms race, the new communications channel
between the US and China — like the nuclear hotlines of the cold war —
will serve as a diplomatic safety valve. By sharing technical
information, officials hope that misunderstandings can be avoided and
problems quickly resolved.
A short-lived outburst from comet 67P/Churyumov-Gerasimenko was
captured by Rosetta’s OSIRIS narrow-angle camera on July 29, 2015. The
image at left was taken at 13:06 Greenwich Mean Time (GMT) (6:06 a.m.
PDT), and does not show any visible signs of the jet. It is very strong
in the middle image captured at 13:24 GMT (6:24 a.m. PDT). Residual
traces of activity are only very faintly visible in the final image
taken at 13:42 GMT (6:42 a.m. PDT).
The images were taken from a
distance of 116 miles (186 kilometers) from the center of the comet. The
jet is estimated to have a minimum speed of 33 feet per second (10
meters per second) and originates from a location on the comet’s neck.
Although Dione (near) and Enceladus (far) are composed of nearly the
same materials, Enceladus has a considerably higher reflectivity than
Dione. As a result, it appears brighter against the dark night sky.
The surface of Enceladus (313 miles or 504 kilometers across) endures
a constant rain of ice grains from its south polar jets. As a result,
its surface is more like fresh, bright, snow than Dione’s (698 miles or
1123 kilometers across) older, weathered surface. As clean, fresh
surfaces are left exposed in space, they slowly gather dust and
radiation damage and darken in a process known as “space weathering.”
This view looks toward the leading hemisphere of Enceladus. North on
Enceladus is up and rotated 1 degree to the right. The image was taken
in visible light with the Cassini spacecraft narrow-angle camera on
Sept. 8, 2015.
Jupiter showers its moon Europa with enough radiation to kill a human
in just a few days. Europa must also contend with the massive planet’s
powerful tidal forces. The moon literally creaks as Jupiter’s bulk rends
its frozen surface in deep crevasses, pushing and pulling the ice
upward and downward by tens of meters every few days. And with only a
very tenuous atmosphere, it is so very cold: -210 degrees Celsius.
Yet as forbidding as Europa’s surface may be, just a few kilometers
below lies the largest ocean in the known Universe. It dwarfs any on
Earth, encircling the entire moon and plunging as far as 100 kilometers
deep. The tidal forces that wrench Europa’s icy surface also tug on the
core of this ocean, dissipating heat and providing ample energy to warm
the ocean.
Outside of Earth, many astrobiologists say Europa’s vast, dark ocean
probably offers the best hope for finding life elsewhere in the Solar
System.
Orion’s thermal protection system is one of the most critical parts
of the spacecraft and is responsible for protecting it and the future
astronauts it will carry home from deep space destinations. It consists
of the spacecraft’s main heat shield that faces into the atmosphere on
reentry to slow the spaceship down and also the grid of tiles known as
the back shell. During Orion’s next mission atop the agency’s Space Launch System
rocket, called Exploration Mission-1 (EM-1), the spacecraft will be in
space for more than three weeks and return to Earth under even faster
and hotter conditions than during its last flight.
[…]
During EM-1, Orion will endure a more intense re-entry environment.
While the spacecraft encountered speeds of 30,000 feet per second during
Exploration Flight Test-1
and temperatures of approximately 4,000 degrees Fahrenheit, it will
experience a faster return from lunar velocity of about 36,000 feet per
second. While the speed difference may seem subtle, the heating the
vehicle sees increases exponentially as the speed increases. The work
engineering teams across the country are doing prepares Orion’s heat
shield to perform re-entry during any of missions planned near the moon
or in high lunar orbit (NASA’s “Proving Ground”) in the coming years.
For these future Orion missions, a silver, metallic-based thermal
control coating will also be bonded to the crew module’s thermal
protection system back shell tiles. The coating, similar to what is used
on the main heat shield, will reduce heat loss during phases when Orion
is pointed to space and therefore experiencing cold temperatures, as
well as limit the high temperatures the crew module will be subjected to
when the spacecraft faces the sun. The coating will help Orion’s back
shell maintain a temperature range from approximately -150 to 550
degrees Fahrenheit prior to entry and also will protect against
electrical surface charges in space and during re-entry.
Not to be confused with the Margaret Hamilton who played the Wicked Witch of the West in The Wizard of Oz, computer scientist Margaret Hamilton wrote the code that allowed humans to land on the moon. As the Director of the Software Engineering Division of the MIT Instrumentation Laboratory, she played a crucial role in the Apollo space program, ultimately preventing a computer overload that would have aborted the Apollo 11 mission.
The concepts Hamilton and her team created are considered the modern building blocks for “software engineering”, a term which she originally coined as an inside joke (long before it became a $400 billion industry). Today, she works as the CEO of Hamilton Technologies in Cambridge, just a few blocks away from where she began her career at MIT.
NASA said Monday the six astronauts were left with one less power
channel Friday. A short circuit in equipment on the station’s framework
is to blame. The short apparently tripped a current-switching device,
resulting in the loss of one of eight channels used to power the
orbiting lab. The affected systems were switched to alternate lines.
NASA spokesman Dan Huot said the crew has been operating normally and is in no danger.
A similar failure in 2014 required spacewalking repairs.
No good spare parts for the job are on board. NASA plans to launch a
replacement on a SpaceX delivery scheduled sometime early next year,
Huot said. SpaceX has been grounded since a failed launch in June.
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