Kommunikation i rymden Mats Holmström Institutet för rymdfysik (IRF) SUNET TREFpunkt Kiruna 30 mars 2004
Översikt ● ASPERA-3 på Mars Express – Vetenskapliga mål och bakgrund – Nuläge ● Mars Express dataflöden – Fysiskt – Format ● Framgångar och problem
Solar System Physics: Scientific Goals Comparative research on the evolution and dynamics of the solar system objects (planets, asteroids, comets, meteoroids) and their interaction with the solar wind. • How does the interplanetary medium affect and shape the bodies in the inner solar system? • What plasma physical processes determine the structure of the interaction regions? • How do the solar system dust population evolve and interact with planetary bodies? 1
Instrument Development and Construction The detectors measure characteristic properties such as energy, mass and/or distribution 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
2003-01-22 The Solar Wind [Parker, 1963] A collisionless plasma 2
2003-01-22 Magnetized Planets [Kivelson & Russell, 1995] Mercury, Earth, Jupiter, Saturn, Uranus, Neptune 4
2003-01-22 Non-Magnetized Planets [Luhmann, 1986] Venus, Mars 5
ENA Production by Charge-Exchange O H + H O +
ASPERA-3 On ESA’s Mars Express mission Launch June 2003 on Russian Soyuz/Fregat Arrives in December 2003 9
ASPERA-3 Delivered June 2002 7
Neutral Particle Imager (NPI)
Neutral Particle Detector (NPD) Three-dimensional view of the NPD principal components Cut-away view of the NPD sensor
�������������������
July 3, 3 Million Kilometers July 3, 8 Million Kilometers
Rymden - En tuff miljö ● Uppskjutning ● Temperatur ● Strålning (Single Event Effects)
Planeternas positioner...
Geometri ● Fri sikt. 5-10 grader över horisonten. ● Avstånd – Bandbredden avtar som 1/d 2 – Latency: Ljustiden (OWLT) ● Riktning (tre-axel stabiliserad) – Markstation: Banbestämmning (centimetrar) – Satellit ● Bestämmning: Gyron. Star trackers. Sun sensors ● Ändring: Reaktion wheels. Thrusters
Markstationer ESA (NNO), NASA (DSN)
Satellit 1.6 m HGA (0.4 m LGA) X-band (7.1 GHZ) till Jorden S-band (2.1 GHZ) från Jorden
Avståndet Mars-Jorden 1/d 2
Bandbredd kbps
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_(331.04,01 MOCS 2 P 04-090T15:28:00.000Z 626 OCC_MARS_START_/_RA_063.82_/_DE_022.41_/_OMP_(325.94,-00.10)_ 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)_/_ MO2E 6 P 04-090T15:50:19.000Z 0 OCC_MARS_200KM_END_/_RA_063.83_/_DE_022.41_/_OMP_(315.61,-29. 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
Resursbehov Sensor-Mode Bit rate [bps] IMA Mode 24 2400 IMA Mode 26 600 ELS Low 68 ELS Normal 260 ELS High 1029 ELS Burst 4100 NPI Normal, High, Burst 265 NPD Low 424 NPD Normal, High 1576 NPD Burst 12328 NPD Raw 34000 Power consumption: 16.8 W without scanner 23.4 W with scanner
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
Dataflödet Mars Markstation Express ESOC IRF Darmstadt Kiruna
Commanding
Kommandofiler POR_ 00085 04-086T14:57:34.000Z 04-091T00:21:16.000Z 04-091T01:48:12.000Z 0079 H1AASF01A2 S H2I UTC T P 000 H3 H4 H5 S1 MPER 0000000256 -00:25:00 S204-086T14:57:34Z matsh@irf.se H1AASF03A1 S H2I UTC T P 010 H3 H4 H5 S1 MPER 0000000256 -00:23:17 S204-086T14:57:34Z matsh@irf.se PVASD6501 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 ...
HRSC
OMEGA: Water on Mars
Solar wind scavenging of the martian atmosphere Planetary wind = Outflow of atmosphere and ionosphere (cometary interaction) ASPERA will do global imaging and in-situ measurements of: Solar Inflow — solar wind wind Outflow — planetary wind using: Planetary wind Energetic neutral atom � 100 ton/day cameras and plasma (ion+electron) spectrometers Note: Mars (and Venus) are planets lacking a strong intrinsic magnetic field (umbrella) => dehydration.
ASPERA-3 — Preliminary results (IMA) Confirmation of the planetary wind - O + and molecular ions Solar wind/sheath (H + , He ++ ) Planetary wind (O + ) MEX orbit Solar wind Planetary wind (O + ) Closest approach Solar wind/sheath Tail/planetary wind QuickTime och en TIFF (okomprimerat)-dekomprimerare krävs för att kunna se bilden.
Recommend
More recommend
