Marspedia - User contributions [en]

Aerobraking

2008-05-29T00:10:34Z

Chris radcliff: fixed misspelling

'''Aerobraking''' is a technique used by mission scientists to reduce the height of spacecraft orbits by allowing atmospheric drag to slow the spacecraft's velocity. Often the solar panels onboard orbiters can be used to maximize and control the amount of drag applied to the craft. This technique will ultimately minimize the requirement for the use of propellants (to slow the craft down), thereby optimizing cost effectiveness.

This technique was used to great effect on missions such as the [[Mars Reconnaissance Orbiter]] in 2006 and [[Mars Odyssey]] in 2001, and is standard practice when spacecraft are being inserted into orbit or when a reduction in velocity is required.

[[category:Spaceflight science]]

Aerobraking

2008-05-29T00:08:57Z

Chris radcliff: Aerobreaking moved to Aerobraking: Misspelled.

'''Aerobreaking''' is a technique used by mission scientists to reduce the height of spacecraft orbits by allowing atmospheric drag to slow the spacecraft's velocity. Often the solar panels onboard orbiters can be used to maximize and control the amount of drag applied to the craft. This technique will ultimately minimize the requirement for the use of propellants (to slow the craft down), thereby optimizing cost effectiveness.

This technique was used to great effect on missions such as the [[Mars Reconnaissance Orbiter]] in 2006 and [[Mars Odyssey]] in 2001, and is standard practice when spacecraft are being inserted into orbit or when a reduction in velocity is required.

[[category:Spaceflight science]]

Aerobreaking

2008-05-29T00:08:57Z

Chris radcliff: Aerobreaking moved to Aerobraking: Misspelled.

#REDIRECT [[Aerobraking]]

Sunlight

2008-05-29T00:05:56Z

Chris radcliff: /* Open issues */ corrected typo

The [[Sun]] is on average 2.28 million km away from [[Mars]]. '''Sunlight''' takes 13 minutes to travel from the Sun to Mars with a power of 589 W/m2. It is not as bright as on [[Earth]] (1367 W/m2). No one has ever seen it, but it probably gives the impression of dawn or dusk during daytime. Colonists should have this impression only for a few days until their visual cortex adapts.

The Martian [[atmosphere]] does not filter sunlight as efficiently as on Earth, leaving to much UV ray and high energy particles to reach the surface. Life is considered not possible without additional shielding against [[cosmic radiation]] (perhaps highlighting the need for an [[Early warning system (solar radiation)|early warning system]]) and parts of the [[solar radiation|solar spectrum]].

The amount of usable energy on the surface is lower due to the rotation of the planet and the angle of the plain. Also, reflection and absorption ([[albedo]]) at the atmosphere must be considered. On Earth the annual usable energy per m2 is about 1000 kWh in Middle Europe and 2400 kWh in the Sahara.

==Facts and figures==
"in the UK we receive an average power of about 125 Wm-2 whilst the Sahara Desert gets 250-300 Wm-2" <ref>[http://cms.ises.org/uploads2/SSF/pictures/materials/307/solarrad.PDF the SOLAR ENERGY society: Solar Radiation - Distribution and Availability of Solar Energy]</ref>.

With 24*365 hours per year this results in an average usable energy per m2 and year of 1095 kWh in the UK and 2190-2628 kWh in the Sahara.

==Open issues==
* What are the psychological and physiological effects of the permanent dim light on humans, animals and plants?
* Are there scientific facts of a positive effect of artificial light to compensate the lack of sunlight?
* What is the annual usable energy on Mars in the equator region?

==References==
<references/>

[[Category: Solar system]]
[[Category: Climate]]