Better Example Crafts: Near Future Propulsion Edition

[Captain Sierra]

Moderator note: Thread was closed on request of the OP.

Anyone familiar with BSC run by Xeldrak will be very familiar with how this works. For starters, I too outsourced the rules and guidelines to a blog entry here.

Better Example Crafts for Near Future Propulsion

Let it be known that Nertea knows about this and has given me some assistance with what kinds of things the crafts should demonstrate for the pack.

For the pack, I usually like the example ships to demonstrate particular concepts that the pack uses.

• A ship with insufficient power to run engines that must use capacitors
  
• Ships using solar power to run engines
  
• A ship demonstrating clustering of many small engines
  
• A ship using the VASIMRs to achieve low and high inefficiencies
  
• A ship using hydrogen-fuelled engines
  
• A ship using xenon-fuelled engines
  
• A ship using argon-fuelled engines
  
• Ships demonstrating the "standard" placement of conformal radiators on reactors
  
• Ships demonstrating use of non-conformal radiators
  
• A tug-type vessel for pushing an Orion or similar
  

Obviously, you'll need to download Near Future Propulsion if you haven't already.

On to the task this time.

We'll be tackling a solar powered craft first. Here are the exact design requirements.

• Craft should use a Dual Stage 4-Grid ion thruster
  
• Craft must not use any reactors for power*
  
• Craftshould require capacitors for pulsed burns
  
• Craft should be reasonably small and must fit within a 2.5m expanded KW Rocketry Fairing**
  

*An NFP update is coming soon which may break compatibility with all crafts using radiators (required for reactors). As such, nuclear power is off limits until I know for certain that the crafts are compatible with the latest version. New engines to expand the possibilities are also coming soon.

**KW Rocketry fairings are not procedural and will be used as a size restriction to ensure crafts are easy to get into orbit, as NFP focuses on in-space propulsion and not getting craft to orbit. That is the job of the person flying, though builders are encouraged to design and include a launch vehicle for their craft. It should not include the KW fairing in the DL.

This particular design requirement is pretty simple. The DS4G is effectively a stronger stock ion engine and is a good starter for people new to the pack, so it will be our first engine for demonstration. The craft should also not be able to fully power itself on solar and must resort to using large battery capacity and capacitors to do pulsed burns. The smallest NFP xenon tank gets you at least 10000 delta V so the delta V department should be easy. Beyond that, it's up to you how you do it.

For an example, I'll leave you with this:

How this works:

Like BSC before this, you will have 168 hours, one week to begin construction. To keep things easy for me, the time officially begins tomorrow at 12 noon EST (eastern time). It will end next Sunday at 12 noon EST. There will then be a 1 week period of voting. If there are more than 10 entries, we will do a preliminary and final round of voting, taking the top 5 from preliminaries. Each vote will have 5 days in such case. It is strongly recommended that you download and test fly the craft files before voting.

Useful Facts:

The DS4G thruster consumes around 220 units of power per second at maximum throttle. It also consumes about 0.1 units of xenon gas per second at full throttle. The smallest NFP xenon tank contains 1500 units, allowing for 15000 seconds, 250 minutes, or over 4 hours of continuous operation! It produces 3 kN of thrust, which is 6x more than the stock PB-ION thruster, so you can get decent acceleration even with heavier craft.

Edited February 17, 2014 by Supernovy
thread closure

[Captain Sierra]

Here is my preliminary entry and I think it serves as a good start with some interesting techniques while producing something I feel is representative of the requirement.

This is the Long Ranger (haha lol). It packs over 13 hours of burn time and has enough solar power to run the engine at about 2/3 throttle. For full speed, capacitor pulsed burns are required. Capacitor battery setup is optimized to prevent power loss and maximize benefit. It has ample torque to turn quickly and stay on course. It weighs in at just over 4 tons. It has not yet been tested orbitally, but I wanted an entry in quickly as an example.

Here it sits on a simple parallel staged launcher with solid first stage for high launch TWR.

Craft file will be uploaded following some finalizing tests and that will complete the entry.

[Dodgey]

Quick question what timezone are you in. I mean how many hours in font of our behind gmt are you.

[Captain Sierra]

Quick question what timezone are you in. I mean how many hours in font of our behind gmt are you.

I'm in the same time zone as I listed, EST. That's 4 or 5 hours behind GMT,I don't remember *exactly* which.

[Mazlem]

EST is GMT -5