Hello Space Fans and welcome to another edition of Space Fan News.
This week, NASA delivers the detectors for the European Space Agency's Euclid Mission,;
SpaceX nails another landing, this time on the ground and not on a barge; and uhhh Houston,
we have a JWST.
NASA earlier this week announced that it has shipped, and ESA has received, the first set
of detectors and electronics that will make up the heart of the two near-infrared detectors
on board the Euclid spacecraft.
The detector systems are key components of NASA's contribution to this upcoming ESA mission
designed to look at billions of faint galaxies in the early universe in an attempt, among
other things, to try and figure out why the universe is accelerating as it expands.
Euclid will carry two instruments: a visible-light imager (VIS) and a near-infrared spectrometer
and photometer (NISP).
The Euclid telescope has a special light-splitting plate that enables incoming light to be shared
by both instruments, which enables them to can carry out observations at the same time.
The spacecraft is scheduled for launch in 2020 and will observe billions of faint galaxies
to, as I said, investigate why the universe is expanding at an accelerating pace.
As I've told you many times, astronomers think dark energy is responsible for this,
and Euclid will explore this hypothesis and its observations will help constrain the dark
energy models that are out there.
This census of distant galaxies from Euclid will also reveal how galaxies are distributed
in our universe, which will help astrophysicists understand how the delicate interplay of the
gravity of dark matter, luminous matter and dark energy forms large-scale structures in
the universe.
And let's not even go into Dark Matter right now, you all know how I feel about that.
Annoying stuff.
So why is Euclid observing in infrared light?
For the same reason JWST is, that's where all the interesting astronomy is happening
in the distant universe.
If you want to look at galaxies far, far away, you'd better be doing it in the infrared
or you won't see much.
Infrared light, which is invisible to the human eye, is the money shot for studying
the universe's distant galaxies.
I know you've heard this example before, but like the Doppler effect for sound, where
a siren's pitch seems higher as it approaches and lower as it moves away, the frequency
of light from an astronomical object gets shifted with motion.
So for stuff moving away from us, light appears redder, and light from those approaching us
appears bluer.
Because the universe is expanding, distant galaxies are moving away from us, so their
light gets stretched out to longer wavelengths.
For the galaxies Euclid is interested in, between 6 and 10 billion light-years away,
the light from the galaxies have shifted to the red so much that they are now brightest
in infrared light.
Euclid observations hold a lot of promise for those looking to understand universal
acceleration.
JWST will contribute, but Euclid is going to help characterize the geometry of the universe
which will tell us a lot about the nature of the dark energy that's supposed to be
accelerating the universe.
I covered the basics of Euclid in SFN 175 so click on the link up here to watch that.
Next, SpaceX has done it again.
They've successfully launched another satellite and landed the first stage, but this time,
they landed on the ground, at the Kennedy Space Center, not on a barge.
I was at the launch but was too far away to see the landing, I did see the launch though,
and it was awe-inspiring as usual.
SFN correspondent Chris Marshall filed this report last week, but because I was sick and
couldn't post an episode, we're airing it this week.
This week SpaceX passed another important milestone for the company as they launched
their first National Reconnaissance Office Payload, let's listen in as the rocket lifts off
This launch was important for SpaceX as it allowed them to break the monopoly that United
Launch
Alliance had on NROL launches going back at least two decades.
As with all NROL launches, the details of the payload and destination were kept secret,
therefore SpaceX did not show any video or data related to the second stage.
However, they did show the return of the booster all the way from separation to landing back
on Landing Zone One at Cape Canaveral Air Force Station.
This was the fifth launch for SpaceX this year and their fourth landing.
Since the introduction of the Falcon 9 they have launched 33 times with one failure in
2015 when the second stage exploded during the CRS-7 mission, they also lost a booster
in 2016 during a static fire fueling process, which also resulted in the loss of the Amos
6 payload and badly damaged Launch Complex 40.
So far SpaceX has landed ten times, six aboard their Autonomous Spaceport Drone Ships and
four at Landing Zone One, one of those boosters was recently reused to launch the SES-10 payload.
SpaceX has several more important milestones planned for this year including the resumption
of launches from Launch Complex 40, the launch of Falcon Heavy and launch of their Crewed
Dragon vehicle.
Finally, Houston we have a JWST!
The mission for the successor to the Hubble Space Telescope has moved to the next critical
phase.
The main telescope is assembled and completed at the Goddard Space Flight Center earlier
this year and has been packed up and shipped to the Johnson Space Flight Center.
Here it will begin cryo testing in a huge Apollo-era vacuum chamber that will simulate
the operating environment at the L2 point, the final stop on JWST's journey in late
2018.
Now when I say packed up and shipped, I'm not talking about a UPS box with a tracking
number.
NASA has built a special container to hold the spacecraft so that it fits in a C5 cargo
plane, the largest plane the U.S. has.
So they packed it up in the container, put it on a special truck that was also designed
just for this mission, drove it in the dead of night through the streets of Washington
D.C., which, let's face it, is about the only time you can get anywhere in that town,
to get to Andrews Air Force base.
That's the same base Air Force One flies out of I think.
Then they put it in a C5 cargo plane and flew it to Texas.
Once it got to Johnson, they took it inside a cleanroom where the telescope was removed
from its special shipping container.
In the coming weeks it will be prepared for a key cryogenic test that will run nearly
100 days.
JWST is being tested like crazy, because once it gets to the L2 point some million and a
half kilometers away, there will be no repair mission to fix anything that goes wrong like
with Hubble.
To ensure the telescope's optics will operate in space, it must complete tests at cryogenic
temperatures in a vacuum.
And this will happen as I said in the biggest and baddest cryogenic-vacuum chamber in the
world: Johnson's Chamber A, the same vacuum chamber where Apollo spacecraft were tested.
This test is critical in that it will verify the performance of the whole telescope as
a system end-to-end at its extremely cold operating temperatures.
After these test at NASA Johnson, the telescope will get packed up all over again and head
out to Northrop Grumman Aerospace Systems in Redondo Beach, California, where the final
assembly will occur and testing with the spacecraft bus and sunshield prior to launch.
Oooh, things are getting tense now, this mission is gonna give us all a heart attack, I can
just tell.
Well that's it for this week Space Fans, thanks to all of you for signing up for our
newsletter which entered you in our first contest, sponsored by Displate.com, and thanks
to them as well.
SFN is made possible by support from Patreon Patrons whose contributions each month contribute
and make these episodes possible.
Please consider giving a dollar or so if you find this program useful.
Thanks to all of you for watching and as always, Keep Looking Up!
Không có nhận xét nào:
Đăng nhận xét