[ad_1]
WRITTEN HISTORY FOR NEWS FROM CBS AND USED WITH AUTHORIZATION
After a six-month trip from Earth, NASA's Mars InSight Mars, advancing to about 12,300 mph in space, will meet Monday in the afternoon in an atmosphere Martian to begin a descent of six and a half minutes. surface, begins a mission of one billion dollars to probe the hidden interior of the red planet.
"The goal of InSight is nothing less than to better understand the birth of the Earth, the planet we live on, and we will do it by going on Mars," said Bruce Banerdt, researcher. main.
On Earth, plate tectonics and the ever-changing mantle have altered the deep interior of the planet, obscuring its history and evolution. But Mars is a smaller planet and much less active than Earth, retaining the "fingerprints" of these earlier processes.
"By mapping these boundaries, these different sections of the interior of the planet, we can then better understand how the planet has formed and how our planet has become such that it can actually live, play and have fun. . So, let's go to Mars. "
A final corrective maneuver was planned Sunday afternoon to slightly change the trajectory of InSight and ensure a targeted landing in a vast plain called Elysium Planitia.
But like all landings on Mars, InSight's fully automated 90-mile descent will go well beyond any direct control – or help – of engineers on Earth. In fact, it will take 8.1 minutes for radio signals to get to the reaction propulsion laboratory in Pasadena, California, where worried scientists and engineers will be waiting to see if the spacecraft has managed to get to the surface.
"We did everything we could, we did everything in our power to ensure our success," said Tom Hoffman, InSight Project Manager. "But you never know what's going to happen."
Nestled in a flying saucer "aeroshell" and protected by a state-of-the-art thermal shield, InSight will begin to dive around 2:47 pm. EST Monday, the braking forces withstood up to 7.4 times the gravity of the Earth, while it slowed down quickly and heated to about 2700 degrees Fahrenheit.
Four minutes later, at an altitude of 12.8 km and now moving at a supersonic speed still of 928 km / h, a 39-foot-wide parachute will deploy, inflating with a force of 15,000 pounds per square foot for slow down the gear at a much more manageable speed. mph or so.
The now useless heat shield will be dropped, exposing the bottom of the LG to the environment, and then 10 seconds later, its three landing legs will unfold and lock into place.
A few seconds later, about a minute before touchdown, InSight's aiming radar down will be activated. It will measure the altitude and rate of descent of the spacecraft and transmit this data to the LG's flight computer.
Finally, within 1.5 km above the surface and descending to about 204 km / h, InSight will be released from the aeroshell and parachute to fall freely.
A second later, twelve small rocket engines will fire, each generating about 28 kg of thrust when they pulse 10 times per second, moving the spacecraft one on one side for avoid the fall of the parachute and the airship.
Reducing its horizontal speed and slowing down to about 5 mph, InSight is expected to land on Elysium Planitia around 14:54, which is about 14:00. local time on Mars.
Fifteen minutes later, after waiting for the dust thrown by the thrusters, the two circular solar panels of InSight unfold to begin charging the batteries of the spacecraft. The bays will generate about 1,300 watts of electricity on the planet, but on Mars, with its relatively dusty atmosphere, they will only manage about 300 to 600 watts.
The entry, descent and landing sequence was programmed to coincide with the passage over NASA's Mars Reconnaissance Orbiter probe, which is programmed to record UHF telemetry transmitted by radio from Insight during its diving to the surface. These data will be stored on board the orbiter and transmitted to the Earth approximately three hours after touchdown.
The real-time data will be returned by two experimental spacecraft known as Mars Cube One – MarCO – A and B, launched with InSight in May. These are the first so-called "CubeSats" to make an interplanetary voyage and the main way for flight controllers to follow the descent of InSight.
Unlike Mars Reconnaissance Orbiter, which is much more sophisticated, the $ 18.5 million MarCO satellite incorporates radio equipment capable of capturing InSight's UHF signals and retransmitting them immediately to Earth at normal frequencies. X band
"If it works, the two MarCO satellites will relay InSight's input, descent and landing data, which will be very cool for the MarCO team and for the InSight team to understand what's going on. immediately with the undercarriage. as much as possible, "said Anne Marinan, Mars Cube One Project Manager at JPL.
Whatever the case may be, InSight – the convoluted acronym for Interior Exploration for the help of seismic surveys, geodesy and heat transport – will send a "tone" Generated by computer directly on Earth seven minutes after touch to indicate his general state of health.
But detailed telemetry will not arrive until the Mars Recognition Orbiter relays its stored data three hours after touching it. The confirmation of the normally deployed solar panels will be relayed by NASA's Mars Odyssey orbiter about five and a half hours after landing.
"I am completely excited and completely nervous at the same time because everything we have done so far makes us feel comfortable being able to land on Mars," said Hoffman. "But everything has to go perfectly. Mars could still throw us a curved ball. "
But if it works, InSight will be profitable with the first detailed look at the inside of Mars, bringing long-sought answers to questions about how the planets were assembled when the solar system merged from a cloud of debris 4.5 billion years ago.
InSight is equipped with two main instruments: the SEIS seismic experimentation (seismometer) internal structure provided by the CNES, the French Space Agency, and the heat flux and physical properties (HP3) probe, provided by the German Aerospace Agency DLR. Both instruments cost European space agencies around $ 180 million.
To function properly, both instruments must be lowered to the Mars surface using a robotic arm. They both require a relatively flat area with no rocks near the base of the undercarriage. The landing site of Elysium Planitia was chosen because it is precisely what it proposes.
"As landing engineers, we really like this landing site," said Rob Grover, InSight's entry, descent and landing manager for Elysium Planitia. "It's flat, there are not a lot of pebbles, it's a very safe place to land."
Engineers will use cameras on the undercarriage to accurately examine the area around the spacecraft to ensure that the instruments are placed in the best possible location.
But it will not be fast.
"It's kind of a slow-motion casual mission compared to a lot of things we've done before," Banerdt said. "It will probably take us two or three months, at least, to get our instruments. We have to do a study of the area in front of our spaceship, make sure we do not put the instruments on a rock or in a hole or something like that.
"Then we pay very close attention to the way we put the instruments. … So it will probably take us a month or two to get the seismometer and another month or so for the heat flow sensor to go down and go to the surface. We are probably looking at the beginning of next spring to start reintroducing this type of Mars science. "
The seismometer is able to detect motions smaller than the width of a hydrogen atom, to record the weak vibrations of distant marsquakes, meteors and even light tugboats caused by the passage of the two small moons of Mars, Phobos and Deimos, to map out the inner structure of the planet.
The self-hammering temperature probe hammers its way up to a depth of 15 feet to measure changes in temperature and, by extrapolation, determine the amount of heat flowing from the core to the deepest.
In a third survey, an accurate analysis of the radio signals of the LG during the rotation of Mars will allow scientists to determine the exact orientation of its polar axis while it is wobbling slowly, or precesses, because of the core "sliding" around the inside. From these data, they hope to determine the size, density and composition of the nucleus.
The goal is to help scientists understand how the terrestrial planets of the solar system – Mercury, Venus, Earth, and Mars – and their evolution in the very different worlds we know today have formed.
"Venus is hot enough to melt the lead," Banerdt told reporters last week. "Mercury has a sunny surface. Mars is pretty cold today, but Earth is a nice place to take a vacation. We would really like to know why one planet goes in one direction and another planet goes in another direction. These answers are in the details of the structure that formed very early in the history of the planet. "
On Earth, this structure has been "somehow scrambled, both by plate tectonics and mantle convection," he said. "And so, the evidence of the oldest processes has been erased."
But on Mars, a planet twice as small as the Earth where plate tectonics and the mantle do not turn, traces of the planet's history are still preserved in the depths of the interior.
"The goal of InSight is nothing less than to better understand the birth of the Earth, the birth of the planet we live on, and we will do it by visiting Mars." said Banerdt. "How can we move from a rock ball without peculiarities to a planet that can or can not support life?
"All these processes take place in the first tens of millions of years," he said. "We would like to be able to understand what has happened, and the clues to it are in the structure of the planet that settled in those early years."
[ad_2]
Source link
