RSID: <<2025-06-28T02:36Z MFSK-64 @ 9265000+1500>>

.
.
.
.
.

This is Shortwave Radiogram in MFSK64

Please send your reception report to radiogram@verizon.net
 

From Eos (American Geophysical Union):

Orbiter Pair Expands View of Martian Ionosphere

Radio signals sent between two Mars orbiters -- rather than
between an orbiter and an Earth-based receiver -- capture
new insights into atmospheric dynamics.

by Sarah Stanley
20 June 2025

Like Earth, Mars is surrounded by an ionosphere -- the part of
its upper atmosphere where radiation from the Sun knocks
electrons off of atoms and molecules, creating charged particles.
The Martian ionosphere is complex and continuously changes over
the course of the day, but its role in atmospheric dynamics and
radio communication signals means understanding it is key for
Mars exploration.

One way to study the Martian ionosphere is with radio
occultation, in which a spacecraft orbiting Mars sends a radio
signal to a receiver on Earth. When it skims across the Martian
ionosphere, the signal bends slightly. Researchers can measure
this refraction to learn about Martian ionospheric properties
such as electron density and temperature. However, the relative
positions of Mars, Earth, and the Sun mean conventional radio
occultation cannot measure the middle of the Martian day.

Now, Parrot et al deepen our understanding of the Martian
ionosphere using an approach called mutual radio occultation, in
which the radio signal is sent not from an orbiter to Earth but
between two Mars orbiters. As one orbiter rises or sets behind
Mars from the other's perspective, the signal passes through the
ionosphere and refracts according to the ionosphere's properties.

The researchers analyzed 71 mutual radio occultation measurements
between two European Space Agency satellites orbiting Mars: Mars
Express and the ExoMars Trace Gas Orbiter. Thirty-five of these
measurements were taken closer to midday than was ever previously
achievable, in effect allowing scientists to see a new part of
the Martian ionosphere.

The new data enabled the research team to calculate how the
ionosphere's electron density changes throughout the day. They
were also able to learn more about how the altitudes of the upper
and lower layers of the ionosphere -- called M2 and M1,
respectively -- vary daily. The new data suggest that the peak
electron density of the M2 layer changes less dramatically during
the day than has been suggested by prior research. The data also
show that the M1 does, indeed, still exist during the midday,
contradicting previous assumptions.

The researchers also used the new data to calculate ionospheric
temperatures. They found that instead of being hottest at midday,
temperatures in the ionosphere rise as the Sun reaches Martian
sunset. Simulations using a Mars climate model suggest that it is
likely winds transporting air, rather than the Sun's direct heat,
that control these temperature dynamics.

https://eos.org/research-spotlights/orbiter-pair-expands-view-of-martian-ionosphere

See also:
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JE008854
.
.
.
.
.

This is Shortwave Radiogram in MFSK64

Please send your reception report to radiogram@verizon.net

 

This week's images ...

.
.
.
.

A pheasant in Bursa, Turkey, among fields of wild lavender.
tinyurl.com/2xmlhax9 ...

Sending Pic:142x196C;
 

.
.
.
.
.

A black and white marble floor from a UK supplier.
tinyurl.com/25zfz6zv ...

Sending Pic:190x143C;



.
.
.
.
.

A Bowl of Beauty Peony at the Univerity of Michigan's Nichols
Arboretum in Ann Arbor. tinyurl.com/2dgmneh6 ...

Sending Pic:155x194C;

.
.
.
.
.

Sunrise over Edinburgh as seen from Bo'ness, Scotland.
tinyurl.com/222q6nb9 ...

Sending Pic:205x139C;


.
.
.
.
.

The sun behind Newhaven Lighthouse in Edinburgh makes it look
like its lamp is illuminated. tinyurl.com/222q6nb9 ...

Sending Pic:155x195C;
 

.
.
.
.
.

Sunrise with boats at Gosport, England. tinyurl.com/26gmhj3s ...

Sending Pic:201x139C;

.
.
.
.
.

A jogger along the George Washington Memorial Parkway at sunrise
in Arlington, Virginia, June 24. tinyurl.com/28x5yhyf

Sending Pic:205x132C;


.
.
.
.
.

A turtle finds relief from the heat in a pond at the Tyler
Arboretum, Media, Pennsylvania. tinyurl.com/2ar3d83f ...

Sending Pic:209x126C;

.
.
.
.
.

A wooden sea defence at dawn near Saltcoats in North Ayrshire,
Scotland. tinyurl.com/222q6nb9 ...

Sending Pic:201x132C;
 

.
.
.
.
.

A walking trail in Nairbobi, Kenya. tinyurl.com/2588yqcj ...

Sending Pic:133x222C;


.
.
.
.

Our painting of the week is "Moving Day" (detail) by Sue Ellen
Ross (American, b. 1941). tinyurl.com/29btvalw ...

Sending Pic:165x204C;
 

.
.
.
.
.

Shortwave Radiogram returns to MFSK32 ...


 

fb