Figure A2. An artistic sketch of the Mars Express Spacecraft on its elliptic orbit around
Mars.
Mars.
Figure A3. Collection and transmission of the data by the radar. The radar collects data at
periapsis and transmits data to Earth at the apoapsis.
periapsis and transmits data to Earth at the apoapsis.
Figure A4. The electronic block diagram of MARSIS.
Figure A5. The five receiver bands. The first one is only for ionospheric sounding. The
other four are for both ionospheric and subsurface soundings.
other four are for both ionospheric and subsurface soundings.
Figure A6. The frequency scan of the radar.
Figure A7. The top figure is a typical vertical profile of the ionospheric data which shows
the apparent altitude values as a function of the frequency. The bottom one is
a typical example of time delay versus frequency plot where the ionospheric
echo and surface reflections are seen.
the apparent altitude values as a function of the frequency. The bottom one is
a typical example of time delay versus frequency plot where the ionospheric
echo and surface reflections are seen.
Figure A8. An example of an ionogram. The vertical and oblique ionospheric echoes as
well as the surface reflection can be seen clearly.
well as the surface reflection can be seen clearly.
Figure A9. An example of a color–coded spectrogram of apparent altitude versus
Universal Time at a frequency value of 1.9 MHz. A typical ionospheric
sounding pass lasts about 36 minutes. The intensity code is shown at the top
of the spectrogram.The hyperbola-shaped echo is at 04:57:02 UT.
Universal Time at a frequency value of 1.9 MHz. A typical ionospheric
sounding pass lasts about 36 minutes. The intensity code is shown at the top
of the spectrogram.The hyperbola-shaped echo is at 04:57:02 UT.
Figure A10. A sketch of the ionospheric density structure that is thought to be responsible
for the oblique ionospheric echoes detected by MARSIS. As the spacecraft
approaches the bulge two echoes are detected, a vertical echo from the
horizontally stratified ionosphere and an oblique echo from the bulge. It is
easily demonstrated that a hyperbola-shaped echo is generated by the
temporal variation of the range to the reflection point as the spacecraft
passes over the bulge.
for the oblique ionospheric echoes detected by MARSIS. As the spacecraft
approaches the bulge two echoes are detected, a vertical echo from the
horizontally stratified ionosphere and an oblique echo from the bulge. It is
easily demonstrated that a hyperbola-shaped echo is generated by the
temporal variation of the range to the reflection point as the spacecraft
passes over the bulge.
Figure A11. The apparent altitude versus time spectrogram. The white line is obtained by
computing the apparent altitude that would occur if the signal is reflected
from a fixed point target with respect to Mars. The observed hyperbola is in
agreement with it. Lower panel shows the radial (red line), eastward (blue
line) and southward (green line) components and the magnitude (black line)
of the magnetic field.
computing the apparent altitude that would occur if the signal is reflected
from a fixed point target with respect to Mars. The observed hyperbola is in
agreement with it. Lower panel shows the radial (red line), eastward (blue
line) and southward (green line) components and the magnitude (black line)
of the magnetic field.
Figure A12. The histogram of the apparent altitude difference between the positions of
the hyperbola apexes and the surrounding ionosphere. The mean value is
14.72 km. The near absence of negative ∆h values indicates that in almost
every case the spacecraft passed almost directly over the closest approach
point to the bulge
the hyperbola apexes and the surrounding ionosphere. The mean value is
14.72 km. The near absence of negative ∆h values indicates that in almost
every case the spacecraft passed almost directly over the closest approach
point to the bulge
Figure A13: Map of magnetic fields of Mars observed by Mars Global Surveyor Satellite
at an altitude of 400 km. In many parts of Mars, it is possible to observe the
east-west structure orientation.
at an altitude of 400 km. In many parts of Mars, it is possible to observe the
east-west structure orientation.
Figure A14. One half (01:02:21UT), one full (01:07:20 UT) hyperbola at the places
where the magnetic field is nearly vertical are seen in this spectrogram.
Lower panel shows the radial (red line), eastward (blue line) and southward
(green line) components and the magnitude (black line) of the magnetic
field.
where the magnetic field is nearly vertical are seen in this spectrogram.
Lower panel shows the radial (red line), eastward (blue line) and southward
(green line) components and the magnitude (black line) of the magnetic
field.
Figure A15. The cartoon showing the formation of the bulges on the ionosphere due to
vertical magnetic field. The bulges are believed to cause the oblique echoes.
vertical magnetic field. The bulges are believed to cause the oblique echoes.
Figure A16. A latitude-longitude map of Mars showing the relationship between the
origin of the oblique echoes and the magnetic field of Mars. Red dots show
the positions of 163 hyperbolas and black dots are the places on the Mars
where the magnetic field is within 20 degrees of vertical. Altitude is 150 km
and only magnetic fields greater than 150 nT are shown. The Cain et al.
(Cain et al., 2003) model is used for the magnetic field.
origin of the oblique echoes and the magnetic field of Mars. Red dots show
the positions of 163 hyperbolas and black dots are the places on the Mars
where the magnetic field is within 20 degrees of vertical. Altitude is 150 km
and only magnetic fields greater than 150 nT are shown. The Cain et al.
(Cain et al., 2003) model is used for the magnetic field.
Figure A17. The number of hyperbola-shaped oblique echoes as a function of the
angle between the magnetic field and the vertical at the apexes of the
hyperbolas. A large peak is observed at around 12 degrees. This plot shows
that oblique echoes tend to originate from regions where the magnetic field
is strong and vertical.
angle between the magnetic field and the vertical at the apexes of the
hyperbolas. A large peak is observed at around 12 degrees. This plot shows
that oblique echoes tend to originate from regions where the magnetic field
is strong and vertical.
