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.  

23

0!

10!

20!

30!

40!

50!

60!

70!

80!

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