"Look up tonight & see Saturn in the sky. Tomorrow, our spacecraft will be part of the planet it studied for so long," Cassini's team said on Twitter
Thursday night.
The probe was running low on fuel, and the 13-year tour of the Saturn system mission must end. The spacecraft will make a deliberate plunge into Saturn's
atmosphere to avoid the small possibility of it crashing into a potentially
habitable moon, in particular Enceladus.
The long-lived spacecraft's fateful dive was the final beat in the mission's Grand Finale, which began in late April Women's Nike Air Vapormax 2018 Pink Australia , through the gap between Saturn and its rings. No spacecraft has ever ventured so close to the planet
before.
On its final orbit, Cassini will plunge into Saturn's atmosphere at tens of thousands of miles per hour, sending back new and unique science to the very
end. After losing contact with Earth, the spacecraft will burn up like a meteor,
becoming part of the planet itself.
"The spacecraft is transmitting the last data from its recorders," Cassini team tweeted on Thursday afternoon.
The spacecraft is in the process of emptying its onboard solid-state recorder of all science data, including the final images taken by its imaging
cameras Nike Air Vapormax 2018 Women's Purple Australia , prior to reconfiguring for a near-real-time data relay during the final plunge. The communications link
with the spacecraft is continuous from now through the end of mission.
Because of Earth's rotation, this 11-hour downlink begins with the NASA Deep Space Network (or DSN) antenna station in California, which then hands off
receiving to a station in Canberra, Australia. From this point the spacecraft
holds this orientation, its antenna pointed toward Earth, for the remaining
several hours of the mission.
According to the mission's final calculations, after beginning its descent into Saturn's upper atmosphere Nike Air VaporMax Plus Australia , the spacecraft is expected to lose radio contact with Earth at 4:55 a.m. PDT (1155 GMT) on Friday.
Cassini will enter Saturn's atmosphere at an altitude of about 1,915 km above the planet's estimated cloud tops, where the air pressure is 1-bar, equivalent
to sea level on Earth. During its dive into the atmosphere, the spacecraft's
speed will be approximately 113,000 km per hour.
According to NASA, when the probe first begins to encounter Saturn's atmosphere Nike Air Max 98 Womens Australia , Cassini's attitude control thrusters will begin firing in short bursts to work against the thin gas and keep
Cassini's saucer-shaped high-gain antenna pointed at Earth to relay the
mission's precious final data.
As the atmosphere thickens, the thrusters will be forced to ramp up their activity, going from 10 percent of their capacity to 100 percent in the span of
about a minute. Once they are firing at full capacity, the thrusters can do no
more to keep Cassini stably pointed, and the spacecraft will begin to tumble.
Cassini is set to make groundbreaking scientific observations of Saturn. Before contact is lost, eight of Cassini's 12 scientific instruments will be
operating. All of the mission's magnetosphere and plasma science instruments,
plus the spacecraft's radio science system Nike Air Max 90 Womens Australia , and its infrared and ultraviolet spectrometers will collect data during the final plunge.
In particular, the spacecraft's Ion and Neutral Mass Spectrometer (INMS) will be directly sampling the atmosphere's composition, which cannot be done from
orbit. It will potentially offer insights into the giant planet's formation and
evolution.
When the antenna points just a few fractions of a degree away from Earth, communications will be severed permanently. The predicted altitude for loss of
signal is about 1,500 kilometers above Saturn's cloud tops. From that point, the
spacecraft will begin to burn up like a meteor.
Within about 30 seconds following loss of signal, the spacecraft will begin to come apart; within a couple of minutes Nike Air Max 97 Womens Australia , all remnants of the spacecraft are expected to be completely consumed in Saturn's atmosphere.
"The spacecraft's final signal will be like an echo. It will radiate across the solar system for nearly an hour and a half after Cassini itself has gone,"
Earl Maize, Cassini project manager at NASA's Jet Propulsion Laboratory, said in
a statement.
Due to the travel time for radio signals from Saturn, which changes as both Earth and the ringed planet travel around the Sun, events currently take place
there 83 minutes before they are observed on Earth. This means that, although
the spacecraft will begin to tumble and go out of communication at 3:31 a.m. PDT
(1031 GMT) at Saturn Nike Air Max Womens Australia , the signal from that event will not be received at Earth until 83 minutes later.
"Even though we'll know that, at Saturn, Cassini has already met its fate, its mission isn't truly over for us on Earth as long as we're still receiving
its signal," Maize said.
On Thursday, other Cassini instruments will make detailed, high-resolution observations of Saturn's auroras Nike Air Max 93 Mens Australia , temperature, and the vortices at the planet's poles.
Cassini's imaging camera will take a last look at the Saturn system on the day before the plunge and will be off during this final descent.
Launched in 1997, the 3.26 billion U.S. dollar Cassini-Huygens mission has been touring the Saturn system since arriving there in 2004. The Huygens lander
separated from Cassini and plopped down on the surface of Saturn's moon Titan
shortly after the arrival. The Cassini probe was scheduled to study the Saturn
system until 2008, but the mission was given two extensions that stretched its
lifetime into 2017. During its journey, Cassini has made numerous dramatic
discoveries.
1st direct freight train service linking E China, Duisburg launched
Super typhoon Talim brings gale and heavy rainfall
CHICA.
