Space.com Heliosphere Explorer 1 (SHE-1) (edit 2009.08.30)

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**1. Lander:**
Start with

**Altair** (Lunar lander), keep it in one piece (

**SSTO**), apply

**COTS** tricks to lower cost.

**2. Habitation and logistics:**
1x

**BA330**, 1x

**ISS Node-1**, 2x

**ISS PMA**
**3. Power source** (20 MW or 20 000 kW for engines)

**a.) use RTG**
- RTG generator

- cooling radiators

**b.) use PV**
- PV cells

- batteries

**4. VASIMR, fuel**
- 20t argon fuel tank for 80t of argon

- 4x VX-5000

**5. Supplies, instrumentation, science** (edit 2009.08.31)

- 20t supplies for 6 people for 6 months

- 40t instrumentation, science, for first evaluation

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**1. = 20t**
**2. = 40t**
**3a.** - using HPM (1MWe/t, text in reference speculates it could work in space, heat sink?) =

**20t**
**3b.** - using SAFE-6400 (0,083MWe/t, heat sink?) = 16 * (16 * SAFE-400) = 16 * 20t =

**320t**
**3c.** - using Solaren PV (0,72 MWe/t) =

**60t** (check above discussion)

- batteries or fuel cells ?

**4.** - 20t fuel tank + 80t fuel =

**100t**
- 4x VX-5000 = 4 * (25 * VX-200) = 4 * 10t =

**40t**
- heat sink = ?

**5.** 20t + 40t =

**60t**
(edit 2009.09.30, added equation)

http://en.wikipedia.org/wiki/Rocket_equation
Isp = 5000

**Ve = Isp * g = 5000 s * 10 m/s^2** = 50km/s (edit 2009.08.31, changed g0 to g, added * multiplication symbol)

**dV = Ve * ln (m1/m2)**
Options:

(using rocket equation,

**Isp = 5000**)

**3a.)** 20t + 40t + 20t + 100t + 40t + 60t = 280t, delta V =

**16,8 km/s**
**3b.)** 20t + 40t + 320t + 100t + 40t + 60t = 580t, delta V =

** 7,4 km/s**
**3c.)** 20t + 40t + 60t + 100t + 40t + 60t = 320t, delta V =

**14,4 km/s**
(using rocket equation,

**Isp = 10000**) (edit 2009.08.31, calculations for Isp 10000)

** 3a.)** 280t full (m1), 200t empty (m2), delta V = 33647,22 m/s =

**33,65 km/s**
**3b.)** 580t full, 500t empty, delta V =

**14,84 km/s **
**3c.)** 320t full, 240t empty, delta V =

**28,77 km/s**
(using rocket equation,

**Isp = 30000**) (edit 2009.09.01)

** 3a.)** delta V =

**99 km/s**
**3b.)** delta V =

**43 km/s**
**3c.)** delta V =

**84,7 km/s**
**Thrust** assuming 60 % efficiency for 4x VX-5000 (edit 2009.09.01, expected efficiency around 80 %)

Isp

**1000s** =

**20000 kW * 0,6 / (1000s * 9,81 m/s^2)** =

**1220 N** (not in operational range of VASIMR)

Isp

**5000s = 245 N**
Isp

**10000s = 122 N**
Isp

**30000s = 41 N**
(edit 2009.08.30, added burn time)

**Burn time**, assuming 80t argon, using equation

**(fuel * Isp * g)/thrust**, numbers are approximate :

Isp

**1000s = 7 days** (not in operational range of VASIMR)

Isp

**5000s = 189 days**
Isp

**10000s = 758 days**
Isp

**30000s = 6646 days** (18+ years)

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We are missing info on heat sink (8 MWt for engines), batteries/fuel cells and radiation shielding mass. I am also avoiding cost discussion until we have stable hardware configuration.

I'm still checking the list, please comment.

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Here are some links for reference: (edit 2009.09.01, references)

I have some assumptions about size and mass of heat sinks, but no real data yet, using this page:

http://en.wikipedia.org/wiki/Thermal_radiation
(2009 U.S. Commercial Space Transportation Developments and Concepts:

Vehicles, Technologies, and Spaceports January 2009)

http://www.faa.gov/about/office_org/hea ... 202009.pdf
Reference Guide to the International Space Station :

http://www.nasa.gov/mission_pages/stati ... Guide.html
VASIMR article on Wikipedia with lots of links:

http://en.wikipedia.org/wiki/VASIMR
This document includes information about maximum possible Isp in 30 000s range.

I have received email from Ad Astra Rocket,

**confirming operational Isp range from 5000s - 30000s**
(edit 2009.09.02)

(VASIMR Plasma Rocket Technology)

http://dma.ing.uniroma1.it/users/bruno/Petro.prn.pdf
About nuclear option:

Seven of the nuclear generators would provide 200 MW of power to enable 39 day one way trips to Mars.

(November 28, 2007 - Vasimr engines plus 200 MW of nuclear "batteries" = 39 days to Mars )

http://nextbigfuture.com/2007/11/vasimr ... clear.html
Hyperion Power Module information:

http://www.hyperionpowergeneration.com/product.html
Link on Wikipedia to get specific energy for SAFE-400

http://en.wikipedia.org/wiki/SAFE-400
Some past projections:

(Future NASA Multi-kilowatt Free Piston Stirling Applications)

This paper describes the preliminary work that will be performed toward development of a nuclear-fission-powered nominal 30 kW Stirling power system for use on the lunar surface with a specific power goal of about 140 W/kg for the Stirling power conversion system.

http://sri.auburn.edu/papers/2006/futur ... irling.pdf
Solar alternative:

(Stretched Lens Array SquareRigger (SLASR): A New Space Array for High-Power Missions)

http://www.stretchedlensarray.com/Paper ... WCPEC4.pdf
· Areal Power Density = 300 - 400 W/m2

· Specific Power = 300 W/kg - 500 W/kg

· Stowed Power = 80 - 120 kW/m3

· Scalable Array Power = 4 kW to 100’s of kW’s

· Super-Insulated Small Cell Circuit = High-Voltage (300-

600 V) Operation at Low Mass Penalty

· Super-Shielded Small Cell Circuit = Excellent Radiation

Hardness at Low Mass Penalty

· 85% Cell Area Savings = 66% to 75% Lower Array Cost

per Watt than One-Sun Array

· Modular, Scalable, & Mass-Producible at MW’s per Year

Using Existing Capacities

Orbital Data for the Planets & Dwarf Planets :

http://www.windows.ucar.edu/tour/link=/ ... table.html
Conceptual Mars mission using 3 VASIMR engines (SHE has 100):

http://www.youtube.com/watch?v=Zj53rVWK5z0