NASA's InSight lander safely touches down on Mars

alexander koryagin написал(а) к All в Nov 18 14:07:40 по местному времени:

Нi, all!

Долго переводить, но почитать о процессе посадки очень интересно, а
также подробный рассказ о том, что аппарат собирается сделать.

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NASA's InSight lander safely touches down on Mars
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Last Updated Nov 26, 2018 7:11 PM EST

Slamming into the thin Martian atmosphere at more than 13,000 mph,
NASA's InSight lander pulled off a blazing six-and-a-half minute 77-mile
plunge to the surface of Mars Monday, using a huge parachute and then 12
pulsing rocket thrusters to settle to a gentle 5-mph touchdown in a
billion-dollar mission to study the red planet's hidden interior.

Utilizing the same entry, descent and landing system successfully
employed by NASA's Phoenix lander in 2007, InSight began its nail-biting
descent at 2:47 p.m. EST (GMT-5) and landed on a broad plain known as
Elysium Planitia at 2:54 p.m. EDT.

When signals reached Earth confirming a successful touchdown, anxious
flight controllers, engineers and scientists gathered at NASA's Jet
Propulsion Laboratory in Pasadena, Calif., burst into welcome cheers,
hugs and applause.

They erupted again when an initial photograph was beamed down, showing
the martian horizon through a lens cover speckled with dust kicked up
during landing. The photo served as confirmation the spacecraft was
working properly after its fiery descent to the surface.

"We spend most of our time visualizing all these bad things that can
happen, but sometimes things work out in your favor," said Rob Manning,
chief engineer at JPL and a Mars landing veteran. "It certainly looked
like it was a very successful and perfect landing."

Vice President Mike Pence tweeted his congratulations to NASA and
Lockheed Martin, InSight's builder, along with "all who made today's
(landing) possible. This marks the 8th time the US has landed on Mars &
the 1st mission to study its deep interior. Incredible milestone!"

The team had good reason to celebrate given the challenges the
spacecraft had to overcome.

InSight's protective heat shield endured temperatures up to 2,700
degrees Fahrenheit, the vehicle "felt" an atmospheric braking force of
7.5 times the force of gravity on Earth and still more as its
39-foot-wide supersonic parachute inflated with a force of 12,500 pounds
per square foot.

After slowing to subsonic velocities, InSight fell free of its parachute
and upper support structure for the final mile to the surface, using a
dozen small rocket motors to reduce its descent rate to about 5 mph
before settling to the surface atop three shock-absorbing landing legs.

InSight did not have the ability to send telemetry directly back to
Earth during its plunge to the surface, but flight controllers at JPL
were able to follow along thanks to a pair of small, experimental
"CubeSats" known as MarCO A and B that were launched along with InSight
last May as part of a technology demonstration project.

As the lander descended, a UНF radio sent telemetry up to the MarCOs,
which then relayed it directly back to Earth. As a backup, the entry was
timed to coincide with the passage of NASA's Mars Reconnaissance Orbiter
overhead. The satellite was programmed to record the full suite of
InSight telemetry for relay back to Earth about three hours after touchdown.

But thanks to the MarCOs, the flight control team already knew the
lander had made it safely to the surface, albeit 8.1 minutes after the
fact. That's how long it took for radio signals from Mars to cross the
90-million-mile gulf to Earth.

And it was an exciting, action-packed few minutes. InSight engineers
were on the edges of their seats listening to Christine Szalai, an
entry, descent and landing engineer at JPL, call out the milestones as
the telemetry came in, painting a picture of events taking place 90
million miles away.

"InSight has passed through peak deceleration," she reported. "Telemetry
shows the spacecraft saw about eight Gs."

A moment later, radio signals resumed after a brief blackout during peak
heating.

"InSight is now traveling at a velocity of about 2,000 meters per second
(4,473 mph)," Szalai said.

"It seems to have passed this very critical point of peak heating, peak
deceleration," Manning observed. "The next big step is parachute inflation."

"InSight is now traveling at 1,000 meters per second (2,237 mph),"
Szalai reported. "Once InSight slows to about 400 meters per second (895
mph), it will deploy its 12-meter diameter supersonic parachute. The
parachute will deploy, nominally, at about Mach 1.7. Standing by for
parachute deploy..."

"Radio science reports a sudden change in doppler," another engineer
added, meaning a change in the frequency of the incoming signals
indicated a sudden change in InSight's velocity.

"Ground stations are observing signals consistent with parachute
deploy," Szalai said, prompting a thunderous round of applause.
"Telemetry shows parachute deployment, radar powered on. Нeat shield
separation commanded."

"This is really good news so far," Manning, serving as a commentator on
NASA TV, said under his breath, listening like everyone else to the
telemetry calls. "Ahh, I'm on pins and needles!"

"We have radar activation where radar is beginning to search for the
ground," Szalai said a moment later. "Once the radar locks on the ground
and Insight is about one kilometer above the surface the lander will
separate from the backshell and begin terminal descent using its 12
descent engines."

She continued a few seconds later: "Altitude convergence, the radar has
locked on the ground (applause)! Standing by for lander separation...
lander separation commanded. Altitude 600 meters... gravity turn,
altitude 400 meters... 300 meters.. 200 meters... 80 meters... 60
meters... 50 meters, constant velocity, 37 meters... 30 meters... 20
meters... 17 meters, standing by for touchdown."

And then came the words everyone in the room was waiting to hear:
"Touchdown confirmed! InSight is on the surface of Mars!" Szalai called
out as the JPL team burst into cheers.

But one last milestone remained: confirmation of solar array deployment.
The arrays were expected to begin opening up about 16 minutes after
touchdown. The MarCO spacecraft were out of range by that point, but
telemetry confirming solar panel deploy was expected Monday night after
a pass by NASA's Mars Odyssey orbiter.

InSight -- the acronym stands for Interior Exploration using Seismic
Investigations, Geodesy and Нeat Transport -- is the ninth lander sent
to Mars by the United States since the twin Viking spacecraft touched
down in 1975. One of the eight previous landers crashed to the surface
in 1999, but InSight's descent marked NASA's fifth success in a row.

Overall, NASA has spent an estimated $22.7 billion sending 23 spacecraft
to Mars since the initial - and unsuccessful - Mariner 3 flight in 1964.
Only 24 of the 57 missions launched so far by any nation, including
combination lander/orbiter flights, have been successful, but NASA's
batting average tops the list with 17 successes in 23 attempts.

Unlike previous projects that primarily studied the surface of Mars to
probe its geology, history and past habitability, InSight is focused on
the red planet's interior, using an ultra-sensitive seismometer and a
sophisticated thermometer to map out the sub-surface architecture all
the way down to the core 2,000 miles below the landing site.

But science observations are not expected to begin until next spring.
First, the Seismic Experiment Interior Structure - SEIS - seismometer,
provided by the French space agency, CNES, and the Нeat Flow and
Physical Properties Probe - НP3 - provided by the German Aerospace
Agency, DLR, must be placed on the surface using the lander's robot arm.

"We have a picture of the ground, and now the work to deploy the
seismometer is beginning," said Philippe Laudet, SEIS project manager
with CNES. "The deployment is going to take abut two or three months. Of
course, we will have some data during the deployments, but the best data
to make the best science will be about the beginning of March."

Engineers plan to spend weeks photographing the surrounding landscape to
identify the best spots near the spacecraft to place the instruments,
looking for the smoothest, flattest-possible terrain.

Then, they plan to rehearse operations with InSight's robot arm to make
sure every step in the instrument-lowering procedure is well understood.
An engineering mockup of InSight is available in a simulated Mars
environment at JPL that will be used to test the hardware and software
needed to get the job done.

But getting the instruments to the surface is just half the job. The
heat probe must then hammer its way into the crust up to a depth of
about 15 feet, a procedure that will take still more weeks to complete.
Only then will science operations commence.

Bruce Banerdt, the InSight principal investigator, said the seismometer
"is really the heart of the InSight mission." It is capable of measuring
vibrations that measure less than the width of a hydrogen atom. As
seismic waves from marsquakes or meteor impacts travel through the
planet, different types of soil and rock will also their shape.

"Scientists understand how to take the shapes of those wiggles, their
frequency, their amplitude, the polarization, the timing, all kinds of
properties of those waves and pull that information out and finally,
after we've gotten many, many marsquakes from different directions, we
can put together a three-dimensional view of the inside of Mars,"
Banerdt said.

The German heat probe will use a spring-driven internal hammer-like
device to pound its way down into the martian soil trailing a cable
carrying sensitive temperature sensors. After some 10,000 hammer blows,
the probe should reach a maximum depth of about 15 feet, pausing along
the way to measure the thermal conductivity of the soil at different depths.

By precisely measuring that thermal conductivity, scientists will be
able to extrapolate the temperature profile all the way to the core.

"And that amount of heat is tied to the geological activity of the
planet," Banerdt said. "It's the heat engine of the planet that drives
vulcanism, it drives tectonic activity, it drives mountain building. So
all the geological processes that happen on a planet are driven by its
heat engine, and we want to measure sort of the vigor of that heat engine."

While the surface instruments are measuring Mars' internal structure,
scientists will be studying the spacecraft's radio signals, noting how
the planet's rotation affects them. They hope to use those data to
pinpoint the orientation of Mars' polar axis and how it changes over time.

"Over the course of a year, we can watch that north pole wobble just a
little bit because of the core sloshing around inside the planet, and
that will give us a very, very tight constraint on the size of that
core, its density and so its composition," Banerdt said.

"That tells us the structure of Mars, the structure of Mars tells us
something about the processes that put that structure together, we can
put that into our models, extrapolate to the Earth and understand how
the Earth formed four and a half billion years ago. And that's really
the crux of the science behind this mission."

https://www.cbsnews.com/news/mars-la...ay-2018-11-26/
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Bye, all!
Alexander Koryagin



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