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 Post subject: Re: Hard Space Redux
PostPosted: Sat Sep 29, 2018 6:58 am 
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One thing I'm looking for is a "universal lander" design - 10-ton and 30-ton variants of a small craft, probably with chemical engines (as "nuclear lightbulbs" are risky in an atmosphere) capable of landing on both atmospheric and vacuum worlds. This is for use as a general interface craft for the smaller starships (such as the Type-S) which are too small to carry both a spaceplane and a vacuum-world lander.

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 Post subject: Re: Hard Space Redux
PostPosted: Mon Oct 01, 2018 7:14 pm 
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Since it is chemical, 10-tons may be too small to give you an effective cargo.

Basically 80% of the volume is going to be taken up by fuel/engines, so with a 10-ton lander, you only get about 2 tons for bridge/passengers/cargo... not much usable space.

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 Post subject: Re: Hard Space Redux
PostPosted: Mon Oct 01, 2018 8:41 pm 
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Cyborg IM1 wrote:
Since it is chemical, 10-tons may be too small to give you an effective cargo.

Basically 80% of the volume is going to be taken up by fuel/engines, so with a 10-ton lander, you only get about 2 tons for bridge/passengers/cargo... not much usable space.

I'm looking for interface capabilities for smaller starships such as a 100-ton Prospector Or will interacting with worlds with breathable atmospheres require larger starships capable of carrying a larger lander?

And will 30 dtons be sufficient for a universal lander?

Still thinking of the nuclear option for interface crafts, as I see this option discussed quite often as a launch vehicle from Earth surface:

http://www.angelfire.com/space/nuclearm ... cript.html

https://en.wikipedia.org/wiki/Gas_core_reactor_rocket

http://www.projectrho.com/public_html/r ... cnrliberty

https://www.nextbigfuture.com/2007/07/g ... berty.html

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 Post subject: Re: Hard Space Redux
PostPosted: Wed Nov 21, 2018 6:23 pm 
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I have updated the Hard Space map. This reflects my rethinking of the Trading Blocs.

The two veteran players in interstellar colonization are the UN - led by Switzerland, Britain, Russia, and some Asian countries including parts of the devastated China; and the International Commonwealth, which is mostly African and Chinese. The American Federation - where Brazil, Argentina, and the former US hold sway - are latecomers to the interstellar scene. However, they are aggressively expanding into further stars using cutting-edge ships with long-range jump drives.

The default setting is the UN Arm, which is mainly British and Swiss in culture, with some strong elements of Southeast Asian culture as well. The biggest corporations around the UN Arm are the Royal British Interstellar Company (RBIC), the Russo-Chinese Zhang-Markov, and the Swiss biotech giant Sanapharm.

ImageHS WIP 21-11-18 by golan2072, on Flickr

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 Post subject: Re: Hard Space Redux
PostPosted: Sun Apr 28, 2019 6:32 pm 
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An interesting interface engine I found on Atomic Rockets

What I am researching is interface craft, especially dual-use craft capable of landing on both worlds with atmospheres and airless rocks. This would be inefficient, but necessary as interface craft for small ships, including Sulaco-style small ones.

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 Post subject: Re: Hard Space Redux
PostPosted: Sun May 05, 2019 2:03 pm 
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I love the ideas for multi-purpose engines, like the SABRE and this one. Human beings can be so clever. If only it were always used for good.


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 Post subject: Re: Hard Space Redux
PostPosted: Mon May 06, 2019 5:59 pm 
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My idea is a multi-purpose shuttle- it can land on airless rocks and worlds with various types of atmospheres.

The cost of this is fuel efficiency, as the shuttle does not specialize - it cannot rely on low gravity to reduce its weight (as a lander for a low-grav vacuum world does), rely on atmospheric oxygen to reduce oxidizer load (as a spaceplane does), or rely on aerobreaking to save fuel (as a spaceplane does). So it is sturdy (and heavy) enough to withstand the gravity of a Size A world, and carries enough fuel to land on one and take off from it with or without an atmosphere. It is only as streamlined as reentry into atmospheres dictates.

Any world expecting commercial traffic would use specially-build, localized craft for maximum efficiency, but exploratory ships will need something capable of landing everywhere.

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 Post subject: Re: Hard Space Redux
PostPosted: Fri May 24, 2019 3:42 pm 
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One thing I am considering is using the reaction drive rules from the Moon Toad Publishing Spacecraft Design Guide, even at a slightly more efficient rating for a fusion-plasma engine. Even at a fuel coefficient of 1 (better than anything in that book), you'll need 1% of the ship's "mass" (actually volume since this is Traveller) per hour of thrust per G. So a typical ship carrying 20% fuel will have a total of 20 hours of acceleration. I like that; very hard and harsh, and gives you a cool fusion plasma engine.

The problem is that this is sufficient to lead you to and from a typical jump point (Earth surface to high Earth orbit, for example) using constant acceleration, but you will have to burn only part of the time and "coast" part of the time to reach further destinations. The big question is how you provide players with a good, playable estimate of travel times, as this is literally within the domain of rocket science.

The alternative is to proceed as I have thought before, and as in Zozer's HOSTILE, with each %1 of the ship's hull in fuel gives you 10 hours of thrust per G.

What do you think?

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 Post subject: Re: Hard Space Redux
PostPosted: Tue May 28, 2019 5:59 pm 
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I can do the math for you. Basically, you have to know the distance between where you are and where you are going.

1G = 9.807m/sec-sec

1 hour of acceleration is 3600 seconds, so 35.3 km/sec velocity after 1 hour at 1G or 127,100 km/hr or 3,050,369 km/day. So 3Mkm per day for 1G for 1 hour of acceleration.. ( I would recommend 35 km/sec and 125,000 km/hr and 3 mega km/day as your simplified speeds for easy calculations)

So for each 1 AU trip (average trip to either Mars or Venus) would be 150 MKm

So the trip takes:

150/3 = 50 days

So 50 days and you burn 2G-Hrs of fuel. (1 G-Hr to accelerate and 1G-hr to decelerate) - YES, there is orbital insertion if desired, but I would simplify that and just say it takes 0.1 G-Hr to enter an orbit.

(at that time scale, you can forget the acceleration/deceleration time)

Either double the G force or double the time (2 G-hr) and you get half the time to get there at double the fuel. Half the acceleration and double the time for half the fuel.

The numbers really work out pretty simply.
:)

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 Post subject: Re: Hard Space Redux
PostPosted: Wed May 29, 2019 3:54 am 
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Thanks!

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