kommunikation i rymden - sunet-projekt mmproj.sunet.se/tp10/slides/rymdkom.pdf · 2004. 3. 29. ·...
TRANSCRIPT
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Kommunikation i rymden
Mats HolmströmInstitutet för rymdfysik (IRF)
SUNET TREFpunktKiruna
30 mars 2004
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Översikt
● ASPERA-3 på Mars Express– Vetenskapliga mål och bakgrund
– Nuläge
● Mars Express dataflöden
– Fysiskt
– Format
● Framgångar och problem
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Solar System Physics: Scientific Goals
Comparative research on the evolution and dynamics of the solar systemobjects (planets, asteroids, comets, meteoroids) and their interactionwith the solar wind.
• How does the interplanetary medium affect and shape the bodies in theinner solar system?
• What plasma physical processes determine the structure of the interactionregions?
• How do the solar system dust population evolve and interact with planetarybodies?
1
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Instrument Development and Construction
The detectors measure characteristic properties such as energy, mass and/ordistribution of the particles (electrons, ions or energetic neutral atoms (ENAs))
• Nozomi (PI). ISAS Mars orbiter. IMI: Ion detector.
• Rosetta (PI). ESA comet orbiter. ICA: Ion detector.
• Mars Express (PI). ESA Mars orbiter.ASPERA-3: ENA, electron and ion detectors.
• Venus Express (PI). ASPERA-4: ENA and ion detectors.
• SMART-1 (CoI). ESA Moon orbiter. D-CIXS: X-ray imager.
Future: Bepi-Colombo (ESA Mercury orbiter), Planet-C (ISAS Venus orbiter).
3
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2003-01-22
The Solar Wind
[Parker, 1963]
A collisionless plasma
2
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2003-01-22
Magnetized Planets
[Kivelson & Russell, 1995]
Mercury, Earth, Jupiter, Saturn, Uranus, Neptune
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2003-01-22
Non-Magnetized Planets
[Luhmann, 1986]
Venus, Mars
5
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OH +
HO+
ENA Production by Charge-Exchange
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ASPERA-3
On ESA’s Mars Express missionLaunch June 2003 on Russian Soyuz/Fregat
Arrives in December 2003
9
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ASPERA-3 Delivered June 2002
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Neutral Particle Imager (NPI)
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Neutral Particle Detector (NPD)
Three-dimensional view of the NPD principal components
Cut-away view of the NPD sensor
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July 3, 3 Million Kilometers
July 3, 8 Million Kilometers
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Rymden - En tuff miljö
● Uppskjutning● Temperatur● Strålning (Single Event Effects)
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Planeternas positioner...
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Geometri● Fri sikt. 5-10 grader över horisonten.
● Avstånd
– Bandbredden avtar som 1/d2
– Latency: Ljustiden (OWLT)
● Riktning (tre-axel stabiliserad)
– Markstation: Banbestämmning (centimetrar)
– Satellit● Bestämmning: Gyron. Star trackers. Sun sensors● Ändring: Reaktion wheels. Thrusters
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Markstationer
ESA (NNO), NASA (DSN)
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Satellit
1.6 m HGA (0.4 m LGA) X-band (7.1 GHZ) till Jorden
S-band (2.1 GHZ) från Jorden
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Avståndet Mars-Jorden
1/d2
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Bandbreddkbps
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Händelser idag
PERICENTRE_PASSAGE_0254_/_SSP_(155.68,-43.34)_/_SZA_050 L34T 303 P 04-090T09:40:17.000Z 0 CAN_LOS_10 KMAS 1013 P 04-090T09:50:57.000Z 0 800_KM_ASCEND KMAS 1014 P 04-090T09:55:50.000Z 0 1200_KM_ASCEND L34H 303 P 04-090T10:04:11.000Z 0 CAN_LOS_06 KMAS 1015 P 04-090T10:04:19.000Z 0 2000_KM_ASCEND KMAS 1016 P 04-090T10:24:53.000Z 0 4000_KM_ASCEND L74T 303 P 04-090T12:06:01.000Z 0 NNO_LOS_10 L74H 303 P 04-090T12:54:07.000Z 0 NNO_LOS_01 A75H 303 P 04-090T13:15:37.000Z 43164 KOU_AOS_02 MAPO 255 P 04-090T13:25:10.000Z 0 APOCENTRE_PASSAGE_0255 A75T 303 P 04-090T13:48:06.000Z 39005 KOU_AOS_10 MO2S 6 P 04-090T15:16:27.000Z 2032 OCC_MARS_200KM_START_/_RA_063.81_/_DE_022.41_/_OMP_(331.04,014.80)_/_SZA_113 MOCS 2 P 04-090T15:28:00.000Z 626 OCC_MARS_START_/_RA_063.82_/_DE_022.41_/_OMP_(325.94,-00.10)_/_SZA_118 PENS 154 P 04-090T15:28:34.000Z 3852 MAR_PENUMBRA_START UMBS 151 P 04-090T15:29:23.000Z 3772 MAR_UMBRA_START MOCE 2 P 04-090T15:38:26.000Z 0 OCC_MARS_END_/_RA_063.82_/_DE_022.41_/_OMP_(321.21,-14.32)_/_SZA_121 MO2E 6 P 04-090T15:50:19.000Z 0 OCC_MARS_200KM_END_/_RA_063.83_/_DE_022.41_/_OMP_(315.61,-29.62)_/_SZA_121 KMDS 1017 P 04-090T16:25:16.000Z 5661 4000_KM_DESCEND UMBE 151 P 04-090T16:32:15.000Z 0 MAR_UMBRA_END PENE 154 P 04-090T16:32:46.000Z 0 MAR_PENUMBRA_END KMDS 1018 P 04-090T16:46:02.000Z 3181 2000_KM_DESCEND A24H 303 P 04-090T16:54:06.000Z 47424 GDS_AOS_06
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Resursbehov
Sensor-Mode Bit rate [bps] IMA Mode 24 2400IMA Mode 26 600ELS Low 68ELS Normal 260ELS High 1029ELS Burst 4100NPI Normal, High, Burst 265NPD Low 424NPD Normal, High 1576NPD Burst 12328NPD Raw 34000
Power consumption: 16.8 W without scanner 23.4 W with scanner
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Dataformat
● Till satelliten:
– Telecommands (TC)
● Från satelliten:
– Telemetri (Payload data, temperaturer, strömmar, ...)
● Datapaket
– CCSDS standard (ESA, NASA,...)
– Felkorrigerande kodning. Komprimering
● 100 Mbit databuss. 12 Gbit massminne
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Dataflödet
Mars Express
ESOCDarmstadt
Markstation
IRFKiruna
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Commanding
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KommandofilerPOR_ 00085 04-086T14:57:34.000Z04-091T00:21:16.000Z 04-091T01:48:12.000Z 0079H1AASF01A2 SH2I UTC T P 000H3 H4 H5 S1 MPER 0000000256 -00:25:00 S204-086T14:57:34Z [email protected] SH2I UTC T P 010H3 H4 H5 S1 MPER 0000000256 -00:23:17 S204-086T14:57:34Z [email protected] E D ON PVASD6502 E D OFF PVASD6503 E D ON PVASD6504 E D OFF PVAS00026 R A D 0 PVAS01026 R A D 0 PVAS01126 R A D 0 PVAS01226 R A D 0 PVAS01326 R A D 0 PVAS01426 R A D 0
...
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SIEMENSHRSC
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SIEMENSOMEGA: Water on Mars
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Note: Mars (and Venus) are planets lacking a strong intrinsic magnetic field (umbrella) => dehydration.
Solar wind scavenging of the martian atmospherePlanetary wind = Outflow of atmosphere and ionosphere
(cometary interaction)ASPERA will do global imaging and in-situmeasurements of:
Inflow — solar wind
Outflow — planetary wind
using:
Energetic neutral atom cameras and plasma (ion+electron)spectrometers
Solarwind
Planetary wind100 ton/day
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ASPERA-3 — Preliminary results (IMA)
Planetary wind (O+)
QuickTime och enTIFF (okomprimerat)-dekomprimerare
krävs för att kunna se bilden.
Solar wind/sheath (H+, He++)
Planetary wind (O+)Solar wind
MEX orbit
Solar wind/sheath Tail/planetary windClosestapproach
Confirmation of the planetary wind - O+ and molecular ions