Differences

This shows you the differences between two versions of the page.

--- blog:articles:general:getting_to_mars [2020/03/11 02:53] – created Phil Ide
+++ blog:articles:general:getting_to_mars [2021/04/15 10:21] (current) – [Days and Sols] Phil Ide
@@ Line 1: / Line 1: @@
 ====== Getting To Mars ======
 {{:blog:articles:general:mars_globe.jpg?direct&300 |Mars}}
+//Edit: updated to include [[#Aldrin Cyclers|Aldrin Cyclers]]//
 There are multiple ways to get to Mars, and each has pros and cons. The one thing they all have in common is orbital mechanics. Some options can get to Mars in a short period of time, while others could take up to a year. Some are better suited for robotic missions, others for crewed missions. This article takes a look at the problems of getting to Mars (and getting back) and what options are available.
@@ Line 7: / Line 9: @@
 ==== Days and Sols ====
-On Mars, the day is almost 40 minutes longer. Since it is both awkward and confusing to have a clock run on an extra 39 minutes and 53 seconds before resetting, Mars was given its own clock which resets after 24 hours in the same way clocks do here on Earth. To achieve this, the Martian second is stretched a little. A Martian second is approximately 1.02749 universal seconds. This gives the Martian clock the same number of seconds per 'day' as on Earth (86,400 in case you were interested).
+On Mars, the day is almost 40 minutes longer. Since it is both awkward and confusing to have a clock run on an extra 39 minutes and 35 seconds before resetting, Mars was given its own clock which resets after 24 hours in the same way clocks do here on Earth. To achieve this, the Martian second is stretched a little. A Martian second is approximately 1.02749 universal seconds. This gives the Martian clock the same number of seconds per day as on Earth (86,400 in case you were interested).
 Incidentally, when early missions to Mars reached their destinations, the mission teams were issued watches that kept Martian time. They were nothing special, just off-the-shelf-watches adjusted to run a bit slower.
@@ Line 110: / Line 112: @@
 Every minute an astronaut/cosmonaut/taikonaut spends in space is a hazard, especially when they are outside the Earth's very protective magnetosphere. Not only are they subject to harmful radiation, but their equipment is too. It should be remembered that cosmic radiation can damage silicon chips. It should also not be forgotten that they are not the only things in interplanetary space. The trade-off between cost and time is also reflected in crew safety: the cheaper the mission, the less safe the crew are. This leaves the space agencies with a dilemma. They must fulfil the mission at the cheapest possible price while keeping the crew safe and still having a reasonable chance of the mission being a success. The higher the cost of a mission, the bigger the onus on the agency to have a successful mission. Getting to Mars (with or without a crew) is a very expensive business.
+===== Aldrin Cyclers =====
+[{{:blog:articles:general:aldrin_cycler.gif?direct&250 |A Mars cycler is an elliptical orbit (green) that crosses the orbits of Earth (blue) and Mars (red), and encounters both planets at the points where it crosses their orbits, although not necessarily on every orbit. }}]
+Cycler orbits are those that regularly visit two or more celestial bodies. Over a hundred ballistic Earth-Mars cyclers have been discovered, and hundreds more non-ballistic cyclers. Non-ballistic cyclers require some powered maneuvers. Ballistic cyclers are the most interesting ones - they can get a vessel from one planet to another at no fuel cost.
+In 1985, Buzz Aldrin - he of 2nd man on the Moon fame - calculated a cyler orbit which became known as the Aldrin Cycler. This is just one type of Mars cycler, but it's powered by an impressive vision that harks back to the science-fiction of the 1950's. Aldrin describes two types of vessel - taxis and castles.
+Taxis take the crew from the planet to the castle and vice versa. This is the only part of the journey requiring the expenditure of fuel. The castles permanently follow the cycler orbit, and provide both a habit of sufficient size it is comfortable for the crew, and a safe haven against the ravages of the interplanetary medium, particularly in regard to radiation.
+The really important point of the Aldrin Cycler is the amount of time it takes to travel between the two planets - 146 days. That's less than five months. What's more, you can have several castles in operation at once, granting you the ability to travel to and from Mars at regular intervals, although only the Aldrin Cyclers grant the 146-day transfer period.
+[[https://Wikipedia.com|Wikipedia]] has a page on [[https://en.wikipedia.org/wiki/Mars_cycler|Mars Cyclers]] that details some of the other cyclers available.
 ===== Future Technology =====
 Plasma rocket engines sound very futuristic, but they actually exist and have done for a while. BepiColombo, a spacecraft destined for Mercury and launched in October 2018, uses an ion-plasma engine, a type of solar-electric propulsion system. [[http://www.adastrarocket.com|Ad Astra]] have been working on their [[http://www.adastrarocket.com/aarc/VASIMR|VASIMR plasma]] engine for some time. Plasma is the fourth state of matter, after solid, liquid and gas. Their engine can heat the propellant (they use argon) somewhere between 5,000,000 and 10,000,000°K.
-{{youtube>IdcOWVm_Ov4?medium }}
+{{ youtube>IdcOWVm_Ov4?medium}}
 This movie (from Ad Astra) shows another method of getting to Mars, by swinging out beyond its orbit and then falling back towards Mars again. It is possible because of the capabilities of the VASIMR engine. Note that **OTV** means //orbital transfer vehicle//, and means the vehicle that goes from Earth to Mars and vice versa (you could call it the mother ship).
@@ Line 153: / Line 166: @@
 These are not all the options, and I'm sure more will come in the future.
+~~socialite~~
+~~DISCUSSION~~