by neufer » Mon Aug 24, 2015 5:00 pm
Curious Jay wrote:
Will Cassini be able to relay scientific data as it takes its swan dive or will it mostly just be lost in interference?
Not really. It would require some special probe to enter first:
The Galileo spacecraft had just a special atmospheric-entry probe that directly entered and returned data:
https://en.wikipedia.org/wiki/Galileo_Probe wrote:
<<The Galileo Probe was an atmospheric-entry probe carried by the main Galileo spacecraft to Jupiter, where it directly entered and returned data from the planet. The 339-kilogram measured about 1.3 meters across. Inside the probe's heat shield, the scientific instruments were protected from extreme heat and pressure during its high-speed journey into the Jovian atmosphere, travelling at 47.8 kilometers per second.
The probe was released from the main spacecraft in July 1995, five months before reaching Jupiter, and entered Jupiter's atmosphere with no braking beforehand. The probe was slowed from its arrival speed of about 47 kilometers per second to subsonic speed in less than two minutes.
At the time, this was by far the most difficult atmospheric entry ever attempted; the probe had to withstand 230 g and the probe's 152 kg heat shield, making up almost half of the probe's total mass, lost 80 kg during the entry. NASA built a special laboratory, the Giant Planet Facility, to simulate the heat load, which was similar to the convective heating experienced by an ICBM warhead reentering the atmosphere combined with the radiative heating of a thermonuclear fireball. It then deployed its 2.5-meter parachute, and dropped its heat shield, which fell into Jupiter's interior.
As the probe descended through 156 kilometres of the top layers of the Jovian atmosphere, it collected 58 minutes of data on the local weather. It only stopped transmitting when the ambient pressure exceeded 23 atmospheres and the temperature reached 153 °C. The data was sent to the spacecraft overhead, then transmitted back to Earth. All the probe's electronics were powered by lithium sulfur dioxide (LiSO2) batteries that provided a nominal power output of about 580 watts with an estimated capacity of about 21 ampere-hours on arrival at Jupiter.>>
http://physics.stackexchange.com/questions/25935/cassini-what-information-could-be-gained-from-the-2017-impact-with-saturn wrote:
Stuart Robbins
<<There are two main science goals for the Cassini death dive into Saturn that I know of. One of them is simply higher scale imagery of objects closer to Saturn as it journeys inwards. The other is that it will fly between the planet and the rings, and based upon the radio signals coming back to Earth, we should be able to, for the first time, directly measure the mass of the rings to within around 10
19 kg. This may seem pretty coarse, but there are several specific prediction papers (including one of mine ...) that estimates the ring mass in multiples of the moon Mimas, which has a mass of 3.8⋅10
19 kg.
A third that I thought of a few hours after writing this is that the spectrometers on board should be able to sample the saturnian atmosphere during entry and send back detailed composition information, just as it did when flying through the plumes of Enceladus.>>
http://saturn.jpl.nasa.gov/mission/saturntourdates/saturntourdates2017/ wrote:
Sept. 9, 2017 292 Distant flyby (altitude = 116,000 km; 72,000 mi) of moon Daphnis
Sept. 9, 2017 292 Distant flyby (altitude = 110,000 km; 68,000 mi) of moon Atlas
Sept. 9, 2017 292 Cassini passage through ring plane [North to South] (60,000 km; 40,000 mi wrt Saturn)
Sept. 9, 2017 292 Closest distance (62,000 km; 39,000 mi) to Saturn on rev number 292
Sept. 9, 2017 292 Distant flyby (altitude = 115,000 km; 72,000 mi) of moon Prometheus
Sept. 9, 2017 292 Cassini views the Earth as it passes behind Saturn's Rings
Sept. 11, 2017 292 Cassini passage through ring plane [South to North] (1,160,000 km; 720,000 mi wrt Saturn)
Sept. 11, 2017 292 Distant flyby (altitude = 84,000 km; 52,000 mi) of moon Titan
Sept. 12, 2017 293 Farthest distance (1,300,000 km; 800,000 mi) from Saturn. Start rev number 293.
Sept. 15, 2017 293 Distant flyby (altitude = 111,000 km; 69,000 mi) of moon Janus
Sept. 15, 2017 293 Distant flyby (altitude = 91,000 km; 57,000 mi) of moon Pan
Sept. 15, 2017 293 Distant flyby (altitude = 86,000 km; 53,000 mi) of moon Pandora
Sept. 15, 2017 293 Distant flyby (altitude = 92,000 km; 57,000 mi) of moon Epimetheus
Sept. 15, 2017 293 End of mission, atmospheric entry into Saturn
[quote="Curious Jay"]
Will Cassini be able to relay scientific data as it takes its swan dive or will it mostly just be lost in interference?[/quote]
Not really. It would require some special probe to enter first:
The Galileo spacecraft had just a special atmospheric-entry probe that directly entered and returned data:
[quote=" https://en.wikipedia.org/wiki/Galileo_Probe"]
[float=right][img3="[b][color=#0000FF]The Galileo Probe[/color][/b]"]https://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/Descent_Module.jpeg/235px-Descent_Module.jpeg[/img3][/float]<<The Galileo Probe was an atmospheric-entry probe carried by the main Galileo spacecraft to Jupiter, where it directly entered and returned data from the planet. The 339-kilogram measured about 1.3 meters across. Inside the probe's heat shield, the scientific instruments were protected from extreme heat and pressure during its high-speed journey into the Jovian atmosphere, travelling at 47.8 kilometers per second.
The probe was released from the main spacecraft in July 1995, five months before reaching Jupiter, and entered Jupiter's atmosphere with no braking beforehand. The probe was slowed from its arrival speed of about 47 kilometers per second to subsonic speed in less than two minutes.
At the time, this was by far the most difficult atmospheric entry ever attempted; the probe had to withstand 230 g and the probe's 152 kg heat shield, making up almost half of the probe's total mass, lost 80 kg during the entry. NASA built a special laboratory, the Giant Planet Facility, to simulate the heat load, which was similar to the convective heating experienced by an ICBM warhead reentering the atmosphere combined with the radiative heating of a thermonuclear fireball. It then deployed its 2.5-meter parachute, and dropped its heat shield, which fell into Jupiter's interior.
As the probe descended through 156 kilometres of the top layers of the Jovian atmosphere, it collected 58 minutes of data on the local weather. It only stopped transmitting when the ambient pressure exceeded 23 atmospheres and the temperature reached 153 °C. The data was sent to the spacecraft overhead, then transmitted back to Earth. All the probe's electronics were powered by lithium sulfur dioxide (LiSO2) batteries that provided a nominal power output of about 580 watts with an estimated capacity of about 21 ampere-hours on arrival at Jupiter.>>[/quote][quote=" http://physics.stackexchange.com/questions/25935/cassini-what-information-could-be-gained-from-the-2017-impact-with-saturn"]
Stuart Robbins
<<There are two main science goals for the Cassini death dive into Saturn that I know of. One of them is simply higher scale imagery of objects closer to Saturn as it journeys inwards. The other is that it will fly between the planet and the rings, and based upon the radio signals coming back to Earth, we should be able to, for the first time, directly measure the mass of the rings to within around 10[sup]19[/sup] kg. This may seem pretty coarse, but there are several specific prediction papers (including one of mine ...) that estimates the ring mass in multiples of the moon Mimas, which has a mass of 3.8⋅10[sup]19[/sup] kg.
[b][color=#0000FF]A third that I thought of a few hours after writing this is that the spectrometers on board should be able to sample the saturnian atmosphere during entry and send back detailed composition information, just as it did when flying through the plumes of Enceladus.[/color][/b]>>[/quote][quote=" http://saturn.jpl.nasa.gov/mission/saturntourdates/saturntourdates2017/"]
Sept. 9, 2017 292 Distant flyby (altitude = 116,000 km; 72,000 mi) of moon Daphnis
Sept. 9, 2017 292 Distant flyby (altitude = 110,000 km; 68,000 mi) of moon Atlas
Sept. 9, 2017 292 Cassini passage through ring plane [North to South] (60,000 km; 40,000 mi wrt Saturn)
Sept. 9, 2017 292 Closest distance (62,000 km; 39,000 mi) to Saturn on rev number 292
Sept. 9, 2017 292 Distant flyby (altitude = 115,000 km; 72,000 mi) of moon Prometheus
Sept. 9, 2017 292 Cassini views the Earth as it passes behind Saturn's Rings
Sept. 11, 2017 292 Cassini passage through ring plane [South to North] (1,160,000 km; 720,000 mi wrt Saturn)
Sept. 11, 2017 292 Distant flyby (altitude = 84,000 km; 52,000 mi) of moon Titan
Sept. 12, 2017 293 Farthest distance (1,300,000 km; 800,000 mi) from Saturn. Start rev number 293.
Sept. 15, 2017 293 Distant flyby (altitude = 111,000 km; 69,000 mi) of moon Janus
Sept. 15, 2017 293 Distant flyby (altitude = 91,000 km; 57,000 mi) of moon Pan
Sept. 15, 2017 293 Distant flyby (altitude = 86,000 km; 53,000 mi) of moon Pandora
Sept. 15, 2017 293 Distant flyby (altitude = 92,000 km; 57,000 mi) of moon Epimetheus
[b][color=#0000FF]Sept. 15, 2017 293 End of mission, atmospheric entry into Saturn[/color][/b][/quote]