Soaring on a terraformed Mars - winter diversions

OK, it's cold outside in Earth's northern hemisphere and here's something
topical.

http://www.webolutionary.com/3d/imag...med_mars-1.jpg

What do you think the soaring possibilities would be on a terraformed Mars
with an atmosphere as dense as Earth's?

For one thing, your compass wouldn't work - there's no magnetic field. The
Sun's heating would be much less but the gravity is only one third that of
Earth. Maybe a hang glider that folds into a backpack?

Speculation, Mr. Spock?

Bill Daniels

Assuming that to qualify as terraformed the Martian
atmosphere would have to be similar to that of the
Earth then if the Martian gravity is one third of Earth's
you would be unlikely to have an atmosphere of the
same density as Earth's.

I asked a similar question a couple of years ago but
it was in the summer - so here goes again. What configuration
of human survivable planet would give the best (i.e.
fastest) soaring conditions. Planet size and mass,
gravity, atmospheric density, heating from the (?)
Sun, proportion of land mass to ocean, precipitation
and cloud amounts etc. would all be interrelated.
Glider configurations would also differ - I guess we
could have bigger spans in low gravity and atmospheric
density planets like terraformed Mars. Only known
or realistic materials for glider design to be considered.

My guess is that the Earth would come out as pretty
close to the optimum planet for Soaring and probably
merits saving (although I realise this isn't thought
necessary by GWB et al) for future generations. On
the other hand if it turns out that the Earth is pretty
useless as a soaring planet we wouldn't need to bother
so much.

John Galloway


MAt 18:06 25 January 2004, Bill Daniels wrote:
OK, it's cold outside in Earth's northern hemisphere
and here's something
topical.

http://www.webolutionary.com/3d/imag...med_mars-1.jpg

What do you think the soaring possibilities would be
on a terraformed Mars
with an atmosphere as dense as Earth's?

For one thing, your compass wouldn't work - there's
no magnetic field. The
Sun's heating would be much less but the gravity is
only one third that of
Earth. Maybe a hang glider that folds into a backpack?

Speculation, Mr. Spock?

Bill Daniels

"John Galloway" wrote in
message ...
Assuming that to qualify as terraformed the Martian
atmosphere would have to be similar to that of the
Earth then if the Martian gravity is one third of Earth's
you would be unlikely to have an atmosphere of the
same density as Earth's.


Venus, with about the same gravity as Earth, has an atmosphere 90 times as
deep and dense (With a surface pressure equal to the water pressure one
Kilometer below the Earth's ocean). Mars, even though much smaller, might
be able to hold an atmosphere with a surface pressure of 1000 mb - at least
for a reasonable time. Assuming the technology to terraform Mars in the
first place, the atmosphere could be maintained at that surface pressure.
This implies that the atmosphere would be much deeper with a surface
boundary layer measured in 10's of Kilometers. (Think really tall
thermals.)

Thinking about a theoretical terraformed Mars make you realize just how much
everything we know about terrestrial aerodynamics and weather depends on the
ICAO standard atmosphere. I guess the first step is to figure out what the
terraformed Mars equivalent of that would be.

It's interesting to think of a 15 meter glider in 1/3 gravity. At 1000 mb
the Reynolds numbers would be the same but the flying weight would be
reduced by 2/3rds. You might want to carry a LOT of ballast.

The Mars year is 687 Earth days so it would be a really long soaring season.

Bill Daniels

On Sun, 25 Jan 2004 15:21:44 -0700, "Bill Daniels"
wrote:

Thinking about a theoretical terraformed Mars make you realize just how much
everything we know about terrestrial aerodynamics and weather depends on the
ICAO standard atmosphere. I guess the first step is to figure out what the
terraformed Mars equivalent of that would be.

It's interesting to think of a 15 meter glider in 1/3 gravity. At 1000 mb
the Reynolds numbers would be the same but the flying weight would be
reduced by 2/3rds. You might want to carry a LOT of ballast.

I suspect you'd need to bring the wing loading up to something like
current practise in order to get into the same Re number regime we're
used to. You could either add lots of ballast (200 kg or so) or reduce
the wing area. If you did the latter at current weights you'd end up
with 3 - 3.5 sq. m of wing. Consider also that the chord should not
be reduced by much, because that reduces Re, so you'd end up with a 5
- 6m wing. The roll rate should be spectacular!

The Mars year is 687 Earth days so it would be a really long soaring season.

The sun is weaker (about 52% of Earthly incident solar radiation) due
to Mars' 37% greater distance from the sun, so the thermals would be
quite a lot weaker, possibly starting later and stopping earlier in
the day. Does anybody on this 'ere ng know anything about when dust
devils are active during the Martian day?

And, sadly, the non-soaring season would also be rather long. OTOH it
wouldn't be so nearly far to tow our trailers to go to the Martian
Antipodes for winter.

--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :

At an astronomy meeting this evening, I obtained a
bit of met data about Mars. Not sure as to how accurate
this all is.
The day (sol) is 24.5 hours long.
The atmospheric pressure is about 6 millibar on the
plains, increasing to a maximum of 10 millibars in
some of the basins such as the Hellas Basin. The pressure
falls off rapidly and is probably negligible in the
highlands and at the top of Olympus Mons.
On the equator the temperature varies between around
+10 centigrade at midday down to maybe -40 centigrade
at night. However this is the surface temperature.
At 2 feet the temperature falls to 0 centigrade, and
at 4-5 feet the temperature is down to -20 centigrade.
Winds have been measured at around 50-60 mph. There
are large scale atmospheric events such as duststorms
which can be global in extent. There are also thought
to be 'dust devils' which are similar in profile to
tornados but which extend up to 30,000ft.
There are clouds which may be water at 15 miles and
carbon dioxide at upto 25 miles.
Mars is about 1/10 the mass of the earth.
There are some ridge features available. Many craters
have ridges about 300ft high at the top. There are
also dunes and step effects with heights of 6-30 feet.
There is a very large valley, Mariner valley which
is much bigger than the rift valley.
Around the base of Mons Olympus there is a ridge which
is four miles high.
There can be carbon dioxide fogs in the Hellas basin.

Wilst the earth year is 365 days, the earth is 93 million
miles from the sun and this distance only varies by
about 4 million miles. However on Mars the distance
to the sun is around 120 million miles at the closest
but over 150 million miles at the furthest.

So the possible gliding conditions appear to be:

Ridge running on Olympus Mons - 4 mile high ridge,
pressure 2-4 millibar, temp around -20 to -60 centigrade,
wind 20-100 knots.

IMC climbs in small very tight dust devils - practice
in tornados first. Probably significant G-force/stress
issues!

Thermal flying - pressure 2-8 millibar, temp around
-60 to +10 centigrade, height range 3-30 ft, flight
time 6-10 hours. This would probably be quite difficult
to achieve as long wingspans would not be compatible
with steep banking at a few feet.

Straight downhill glides at very shallow angles (LD
may need to be several 100 or 1000) from the top of
the Hellas basin, or across/along the Mariner 'rift'
valley.

Thus I think the glider would need to fly in very low
atmospheric pressure of 0.1 to 10 millibars, in a temperature
range of -80 to +20 centigrade. It would need to be
strong enough not to break up in the local dust devils.
Have an excellent LD and possibly very small wingspan.

I suspect that we will need to sort out our local stratospheric
soaring before we can build a glider to fly successfully
in these conditions.

Rory O'Conor