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Can metal‐combus/on power systems enable
mid‐dura/on explora/on missions to:
Venus?
The Aitken Basin?
Titan?
A 2011 NASA Ins/tute for Advanced Concepts Proposal
PI: Michael Paul (Penn State); with John Dankanich (Gray Research), James Kas/ng (Penn State), Geoffrey
Landis (NASA GRC), Tim Miller (Penn State), and Steve Oleson (NASA GRC)
Non‐Radioisotope Power Systems For
Sunless Solar System Explora/on Missions
Non-‐Radioisotope Power Systems for Sunless Solar System Explora9on Missions
• A five-‐day (120-‐hour) mission on the surface of Venus • Powered by a Lithium-‐CO2 combus9on system • A S9rling Engine provides electricity to the lander • Direct-‐to-‐Earth Communica9ons from surface • Science goals aligned to Decadal Survey and VEXAG goals • Instrument suite derived from recent public mission concepts* • Atmpospheric sampling during descent • Panoramic Surface imaging • RAMAN LIBS spectrometer for surface composi9on • Cost Es9mate is within New Fron9ers cap (FY15$) • 5-‐Day baUery powered mission would require addi9onal 850 kg of baUeries, with addi9onal system-‐level growth!
Previous Venus landers have lasted less than 2 hours. Recent mission concepts last ~10 hours and cost as much as a Flagship mission.
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90!
2! 3.0! 20! 30! 63! 90!Time (min)!
Altit
ude
(km
)!
ASI Measurements Begin!
Deploy Parachute!& Heat Shield Separation! Deploy Landing Legs!
Release Parachute!& Backshell!
NMS & TLS Measurements Begin!
Descent Imager!
Landing and HG Antenna Deployment!
ALIVE Entry Descent and Landing
Launch and Cruise Phase and Arrival at Venus • Launch on an Atlas V 411 with lunar/earth flybys • 2070 kg launch mass at C3 = 6.2 km2/s2 • 4-‐m aeroshell fiUed with deck for cruise phase solar power
and propulsion • Shallow entry angle 3.92 km/s V∞ at arrival minimize risk • Landing at Ovda Terra provides long view period to Earth
* Venus Intrepid Tessera Lander, GSFC 2010,Venus Mobile Explorer, GSFC 2009
Genesis Derived Heat Shield and Backshell
Li Burner !(500kg/m^3)!
MgAl (1700kg/m^3)!Burner!
Battery NaS (500°C)!
Specific Energy! 1.3 kWehr/kg(Li)! 0.75 kWehr/kg(MgAl)!!
0.300 kWehr/kg!
Energy Density! 650 kWehr/m^3! 1200 kWehr/m^3! 350 kWehr/m^3!!
Mass of Reactants!(Power Rq 1800W for 5 days) 215 kWeHr!
200 kg (Li) + 10 kg tank/burner+ 25 kg Duplex Stirling!
289 kg (Mg/Al) + 60 kg tanks+ 25 kg Duplex Stirling!!
817 kg +10kg Stirling cooler !
Volume of Reactants! 0.3 m^3 (Li) !!
0.17 m^3 (MgAl)! ~1 m^3 (w packing factor)!
Products! Li2CO3 (2100 kg/m^3) (melt 618°C)!
Various (solids)! NA!
Heat of latency! 0.117 kWthHr/kg/ latent 0.178 kWHr/kg Sensible!(180°C melt pt)!(Can absorb 48 kWthHr phase change, Li starts at 0°C )!
.086 kWthHr/kg latent, 0.182 kWthHr/kg sensible!(437°C melt pt)!
• Lithium fueled combus9on systems have a 40+ year heritage at ARL • Li-‐C02 is a new spin on an old technology that would need tes9ng • Other metals (MgAl – see below) offer alterna9ves that change the mass/
volume/energy trade and should be explored to maximize opera9onal 9me on the surface of Venus
