Wednesday, December 16, 2009

Space Travel Part One- The Early Years

The major influence on human activity for the past two hundred years has been the discovery and exploitation of interstellar space. The invention of the Alcubierre drive in 2101 enabled faster than light travel within reasonable timeframes. A Drive technology has enabled the nations of earth to colonize and explore stars out to one hundred light years from earth.

A Drive
In 1994, the Mexican physicist Miguel Alcubierre proposed a method of stretching space in a wave which would in theory cause the fabric of space ahead of a spacecraft to contract and the space behind it to expand. The ship would ride this wave inside a region known as a warp bubble of flat space. Since the ship is not moving within this bubble, but carried along as the region itself moves, conventional relativistic effects such as time dilation do not apply in the way they would in the case of a ship moving at high velocity through flat space-time.
This method of travel does not actually involve moving faster than light in a local sense, since a light beam within the bubble would still always move faster than the ship; it is only "faster than light" in the sense that, thanks to the contraction of the space in front of it, the ship could reach its destination faster than a light beam restricted to travelling outside the warp bubble. Thus, the Alcubierre drive does not contradict the conventional claim that relativity forbids a slower-than-light object to accelerate to faster-than-light speeds.
Further development of warp theory in the 2060s by both Japanese and European space agency’s led to the first working drive which was attached to a joint venture probe ship. On the 1st of September 2072, the Hikari Explorer, an unmanned probe launched to explore earths closest neighbor- Proxima Centauri. The probe was a success finding a system of three planets, one tidally locked within Proximas habitable zone.
Both the JSA (Japan Space Authority) and the ESA (European Space Authority) signed a joint agreement to mount a manned mission to Alpha Centauri and by 2079 the Chinese, American and Russians had signed up to be part of the program. The combined efforts of these countries enabled the building of the Hikari Wanderer, the first A Drive explorer vessel. The ship would be manned by a large multinational crew with the overall command given to the Japanese Air Force Officer Junichi Asano who was tasked with molding together one hundred and eighty crew from twenty four countries.

The construction the Wanderer was the single most complicated construction project in the history of humanity. The technology of the A Drive worked on the principle of the more power fed into the, the faster you travel the only problem was that the generation of the “warp bubble” was severely retarded by the effects of gravity forcing ships to use conventional drives to get themselves away from the effects of a stars gravitational field. The ideal distance is around one thousand diameters from the star, a single diameter is approximately 1.3 million kilometers so to enable the A Drive, Wanderer would have to travel over one billion kilometers using traditional hydrogen fueled drives to get to this point although a fraction of the distance, the journey to this point would take eight months from the moon orbit. This is where the first limitations of the A Drive technology became apparent- .01% of the journey takes 99% of the time, mass and power.

An A Drive jump, although, takes massive amounts of power discharged from energy stored in capacitors it is relatively quick compared to conventional drives, the Wanderer was a huge vessel incorporating a large spin habitat and survey instrumentation but the conventional drive and its hydrogen fuel took up nearly 60% of the total mass of the ship. Later designs would explore more mass saving methods of propulsion but the hydrogen drives built into Wanderer remain in wide use today as the fastest means of moving about a system.
The actual jump to Alpha Centauri took just under three days and equated to a drive efficiency of one light year per day, today this would be seen as relatively poor in comparison to modern technology but that first jump changed the human race forever and opened the door to a new age of discovery. It also highlighted the second major drawback of the A Drive- charge build up.
The theory of the A Drive did not take into account the need to clear charge buildup from the drive arrays. This buildup increases with the time spent in A Space and with the amount of power applied to the drive array manifesting itself in the form of heat. Active and passive cooling systems can alleviate the problem but there comes a point where the amount of cooling is overtaken by the heat generated forcing the shutdown of the drive systems before they become critically damaged. Practical limits of the amount of mass that needs to be transported to the 1000 diameter limit versus the amount of fuel needed to get it there has put limits on the range of A Drive vessels, Wanderer arrived in the Alpha Centauri system with a drive that required four days to cool. Modern designs, mainly military couriers and high speed freighters carrying non-perishables, can reach up to three light-years per day but still only have four to five day duration. The longest jump made by the experimental scout vessel RV Thomas G Thompson, a US Navy ship, was 18.7 ly in 2172.

Arriving in the Alpha Centauri system the crew of the Wanderer were greeted by three stars all of which had worlds within their habitable zones, the first explored was the world which would later become known as New Earth which orbited the largest star Alpha Centauri A. In total the system had over eighteen major worlds including two large gas giants only one, New Earth, had an atmosphere humans could operate in albeit using Mars style environment suits. The experience gained in colonizing Mars thirty years before and the start of the terra forming process on a largely barren world gave hope to permanent settlement on New Earth. The one thing the explorers did not find was life. New Earth had all the signs of a planet that, like Mars, once had standing water and a viable atmosphere but there were no sign that this world or any other within the Alpha Centauri system ever supported life of any kind. Now with the exploration of hundreds of worlds, we have found life in multiple forms but at the time it was expected there would be at least some sign that we were not alone- it was not to be.
Junichi Asano noted in his diary 23rd June 2085- “We all came with an unspoken expectation that as a race we would finally find we were not alone, Alpha Centauri was going to provide us positive indications of other life outside our own system but it was not to be. We found an amazing system of planets orbiting three stars that were so different to our own sun that we were hard pressed to collect enough data, every discovery pushed the boundaries of our knowledge, every new discovery lead to even more questions but the holy grail; life, was not to be found”

The discovery of new earth gave the nations of old earth something they had never had- perspective. The realization that the human race had finally “slipped the bonds of earth” gave a kick start to the UN starting a process that would later be known as the Berlin Protocols. It was recognized that the commercialization of space was now a reality, interplanetary and interstellar space were now open to both private and national interests and with this the world as a whole realized that if any one power held control over space they would effectively hold the high ground and control the Earth and all who lived there. The solution was found in the Berlin Protocols which effectively designated the orbital real-estate around the home planet as a demilitarized zone, activity would be monitored by the United Nations using resources drawn from each of the Earths nations, although not all nations signed up initially there was enough to enforce the Protocols. Eventually this would develop into the United Nations Orbital Management Authority (UNOMA) and as exploration, colonization and commerce expanded the taxes levied on goods entering earth space funded the policing. UNOMA also took on important role- quarantine.

Over the next fifty years the first wave of exploration burst out from Earth. Nations teamed with corporate interests to expand into the near neighborhood and by 2135 eight new colonies had been founded, most with multiple nations claiming a piece. Technology advanced at a pace not seen since the turn of the millennium, raw materials scarce on earth now became cheaper. Electronics and computing power improved to cope with space travel and advanced manufacturing techniques and zero-g factories produced the building materials for an ever increasing starship building industry. The ultimate expression of this rapid advance was the Orbital Elevator.
In 2138 UNOMA issued a tender for the building of an Orbital Elevator which would transfer cargo to and from orbit without the need for expensive interface vehicles. Advances in materials allowed for this to be built but it would still require a major feat of engineering. In 2140 the combined might of the Japanese firm of Mitsubishi, US giant General Electric and the European conglomerate Eurospace teamed up to win the tender. The first work on the foundations began off the coast of Singapore and in orbit in 2142 and by the following year both the foundation anchor and the tethering asteroid were in place. The cable itself was manufactured using ore mined from the tethering asteroid, the process forming the structure for what would later become the industrial hub of Gateway Heights.

By 2150 the first “train” made the six day journey to Gateway Heights carrying a load of Industry leaders, politicians and media for a grand opening ceremony in the zero-g caverns of the asteroid, the President of Singapore noted in one of the opening speeches-
“No longer are we tethered to the Earth, travel beyond the planet is now within the reach of ordinary people, we are all now citizens of the stars”
Although this opened up the elevator to commercial traffic it would be another ten years before the massive spin habitat of Gateway would be completed, this in itself in many ways rivaled the building of the elevator cable. Rotating around the cable itself the 4.5km long tube housing three floors of commerce, residential and retail and at any one time having a population of 850,000 people is capable of docking over one hundred ships in the docking structures fixed to the top and bottom of the huge space station. Capable of maintaining .8G gravity due to the massive radius of the tube, Gateway serves as the common hub for all interaction between Earth and the rest of known space. Before gateway freight had to be delivered from orbit to the surface by either Automated Containerized Reentry (ACR) or by shuttle. Getting product and people to the surface from orbit was easy and relatively inexpensive but getting from the surface to orbit was extremely difficult. Most durables that could withstand the acceleration we launched into orbit by one of several mass drivers located around the planet, the containers, once in orbit were recovered by automated cargo handlers and delivered to their corresponding orbital stations, ok for stuff that wasn’t affected by acceleration but no good for getting people to orbit.
For the pre elevator space traveler the most expensive part of the journey was getting into orbit via shuttle. Several companies offered regular services to the three orbital ports that handled passengers and perishable cargos but they were only for the well heeled or the Government and Cooperates. Gateway consolidated this into a single operation now serviced by both the elevator and shuttle craft, the elevator still can’t beat the speed to orbit of a shuttle. Mass drivers still continue to deliver bulk durables into orbit and there is still a huge traffic of ACR delivered cargo as they remain cost effective ways of transporting goods, but all this traffic in one way or another is handled through the Gateway complex and tax is gathered by UNOMA for each and every person and ton that comes through.

The elevator today consists of Anchor, the manmade Island off Singapore that handles all operations groundside and through which the cable is tethered three kilometers deep into the earth. Gateway, the orbital port and habitat, plus Gateway Heights which is now home to the largest zero-g industrial precinct in human history, there has been zero-g manufacturing for years but not to the scale found at Gateway Heights.
The cable itself is capable of generating enough solar energy to supply all its needs plus sell off excess to Singapore and Indonesia and provides employment to over 17,000 people directly and over one hundred times that number indirectly; economists credit the elevator with ushering in an economic revival to the whole region and lifting the living standards of millions.

All starships produced from the late 2100s to the current day consist of a more or less standard set of components, like a ship or an aircraft form follows function and although each manufacturer or class of ship looks and operates differently they all share common components that enable them to function. Obviously cargo ships devote space to cargo, warships to weapons and passenger ships to passengers but more or less each ship shares common features and the same general layout.

Starting from the front or “bow” the A Drive array forms a bulbous structure that encloses the field generator and capacitors, the faceted external panels act as radiators to handle heat buildup. A central spine extends the length of the ship to the fusion reactor, conventional drive and fuel storage.
The rear or “stern” is dominated by the exhausts from the High Efficiency Plasma Re-combustion drive or HEPLAR. The fusion reactor is used to heat the hydrogen to a plasma state while holding it in a magnetically managed containment chamber under massive pressure, fusion begins and the superheated mass is ejected through the exhaust nozzles creating thrust. The principle is similar to the way a star operates and generates massive amounts of heat, thrust and light. Operating HEPLAR drives can be detected at vast distances due to their emissions and Military ships have a secondary Ion Drive which can be used in situations where stealth is needed although the thrust generated from these is a lot smaller they are not as easy to detect as the HEPLARs.

Rotating around the middle is a spin habitat that generates a maximum of around .6g enabling the crew to function for extended periods in space. Spin habitats are usually of a ring design with access to the spine through multiple spokes. Crew comfort can vary from different watches sharing bunks or “hot bunking” to each crew member having their own stateroom, commonly officers will have their own stateroom while senior crew will share two to a room, junior crew six or more. The worst duty for crew is in the few ships like fast couriers or long range survey craft where the need for streamlining for planetary landing and mass constraints does not enable the installation of spin habitats.

Warships generally have a mass driver running along this spine for launching ordnance while cargo ships will have their whole length taken up by bulk storage or containers; passenger ships have their spin habitat extending the length of their spine. A ships total length can vary depending on usage, the larger container ships and bulk haulers can hit almost a kilometer from bow to stern, some of the bigger warships can also be this long but usually ships average around the three hundred to four hundred meter mark.

Most ships have a collection of smaller service craft that enable them to liaise between other ships, orbital facilities and the surface of worlds although not all ships have a dedicated vehicle for ship to surface travel that involves atmospheric reentry, large commercial carriers have no need to interface with a planet’s surface, they travel between worlds whose orbital facilities can accommodate their needs without having any interaction with the planets themselves. Docking bays or hangers are usually located in clusters along the central spine. All ships carry a full complement of survival suits and escape pods, this is determined by UN mandate, every crew and passenger must have a survival suit and space in an escape pod, these are located in clusters mounted on the outside of the spin habitat and accessed through floor hatches. An escape pod must be capable of supporting its occupants for a minimum of one week and be capable of reentry and enough maneuverability to get itself away from a stricken ship.

Freedom of the Stars
There have been several major losses over the years, usually through drive malfunction or object strike, the worst incident occurred when the passenger liner MS Freedom of the Stars was struck by a one meter long nickel iron meteor on the 26th February 2162 while in transit through the system of Delta Pavonis, the colony world of Port Anguilla is a popular destination for both settlers and tourists. The meteor was not detected by the ships countermeasures system and crashed through the spin habitat and severed the ships spine just in front of the drives. The initial impact, although not fatal in itself, severed the main power and drive from the ship, backup systems were unable to maintain the life support for the 4300 passengers and 1300 crew, a major part of the solar array mounted to the outside of the spin habitat was destroyed in the first impact. Hull integrity within the spin habitat and the forward control compartments in the spine was maintained but not before 476 passengers and crew lost their lives to decompression.

The remainder of the passengers were embarked in life boats accompanied by the surviving crew that were in the spin habitat at the time of impact, the bridge crew remained sealed in the bridge compartment and attempted to manage the situation as best they could. Communications were maintained with Port Anguilla and Captain Jorge Erickson held his shattered ship and crew together until rescue arrived. The lifeboats were kept in close but far enough away to be clear of the debris field, this enabled all to be recovered and limited the casualties to those killed in the initial impact.

Rescue operations were mounted quickly but it took the best part of a week for the first ship, the freighter Androssen to reach the wreckage. When it did arrive it had no way to slow the wreck down or the facilities to take on such a large amount of people, just matching vector and velocity was enough to use most of its fuel reserves. Time was critical. Androssen could only keep station for eight hours before having to break off and return to Pt Anguilla Orbital. Androssen was a midsized container ship so it was decided to dock the lifeboats to empty container anchor points and leave the passengers in them for the journey back. By this time conditions on board the lifeboats were becoming dire, food and life-support were low and there was no way to get to the boats once they were docked into the container bays. During all this the Captain Erickson and his crew remained at their stations with the full knowledge that there was not going to be any way to get them off.
Androssen broke off from the Freedom of the Stars with six minutes to spare and commenced the burn that would take them back to safety; Capt Erickson maintained contact for another two weeks before the remaining power failed. The passengers and crew locked in their lifeboats aboard the Androssen began to die from lack of oxygen and starvation and by the time the French Frigate La Fayette managed a rendezvous four days later only two hundred and six people were able to be saved.
The loss of such a large ship with so many passengers highlighted the danger of space travel, it is a big universe and you are always a long way from help. Since then all ships have standard docking systems and the ability to connect docked ships to power and life support. Life support on all ships can now accommodate four times the crew number in an emergency and life boats have to be rated at one year per person for life support.
All orbital facilities on the major shipping and tourist routes now have dedicated rescue ships capable of coping with emergencies such as the Freedom wreck but the fact remains that it is a dangerous pastime.

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