2 Nanotechnology and space Ralph C. Merkle Principal Fellow, Zyvex

3 Three historical trends in manufacturing More diverse More precise Less expensive Overview

4 The limit of these trends: nanotechnology Fabricate most products consistent with physical law Get essentially every atom in the right place Inexpensive (less than $1/kilogram) Overview

5 Coal Sand Dirt, water & air Diamonds Computer chips Wood Why it matters Overview

6 The principles of physics, as far as I can see, do not speak against the possibility of maneuvering things atom by atom. Richard Feynman, Over forty years ago There’s plenty of room at the bottom

7 The book that laid out the technical argument for molecular nanotechnology: Nanosystems by K. Eric Drexler published in ’s and 1990’s

8 National Nanotechnology Initiative Announced by Clinton at Caltech Interagency (AFOSR, ARO, BMDO, DARPA, DOC, DOE, NASA, NIH, NIST, NSF, ONR, and NRL) FY 2001: $497 million Today

9 President Clinton on the NNI “Imagine the possibilities: materials with ten times the strength of steel and only a small fraction of the weight -- shrinking all the information housed at the Library of Congress into a device the size of a sugar cube -- detecting cancerous tumors when they are only a few cells in size.” Today

10 “Nanotechnology” has been applied broadly to almost any research where some dimension is less than a micron (1,000 nanometers) in size “Molecular nanotechnology” is focused specifically on inexpensively making most arrangements of atoms permitted by physical law Definitions

11 Possible arrangements of atoms. What we can make today (not to scale) Definitions

12 The goal: a healthy bite.. Definitions

13 Positional assembly (so molecular parts go where we want them to go) Self replication (for low cost) Fundamental ideas Nanotechnology

14 H. J. Lee and W. Ho, SCIENCE 286, p. 1719, NOVEMBER 1999 Manipulation and bond formation by STM Positional devices

15 Saw-Wai Hla et al., Physical Review Letters 85, , September Manipulation and bond formation by STM II Positional devices

16 Theoretical proposal for a molecular robotic arm Positional devices

17 σ:mean positional error k: restoring force k b : Boltzmann’s constant T:temperature Classical uncertainty

18 σ:0.02 nm (0.2 Å) k: 10 N/m k b : 1.38 x J/K T:300 K Classical uncertainty

19 Synthesis of diamond today: diamond CVD Carbon: methane (ethane, acetylene...) Hydrogen: H 2 Add energy, producing CH 3, H, etc. Growth of a diamond film. The right chemistry, but little control over the site of reactions or exactly what is synthesized. Molecular tools

20 A hydrogen abstraction tool Molecular tools

21 Some other molecular tools Molecular tools

22 A synthetic strategy for the synthesis of diamondoid structures Positional assembly (6 degrees of freedom) Highly reactive compounds (radicals, carbenes, etc) Inert environment (vacuum, noble gas) to eliminate side reactions Molecular tools

23 A hydrocarbon bearing Molecular machines

24 Molecular machines A planetary gear

25 The Von Neumann architecture ComputerConstructor Self replication

26 Molecular computer Molecular constructor Positional deviceTip chemistry Drexler’s architecure for an assembler Self replication

27 Self replication main(){char q=34, n=10,*a="main() {char q=34,n=10,*a=%c%s%c;printf(a,q,a,q,n );}%c";printf(a,q,a,q,n);} A C program that prints out an exact copy of itself

28 Self replication Print the following statement twice, the second time in quotes: “Print the following statement twice, the second time in quotes:” English translation:

29 Von Neumann's constructor 500,000 Mycoplasma genitalia 1,160,140 Drexler's assembler 100,000,000 Human6,400,000,000 Complexity of self replicating systems (bits) Self replication

30 An overview of self replicating systems for manufacturing Advanced Automation for Space Missions, edited by Robert Freitas and William Gilbreath NASA Conference Publication 2255, 1982 A web page with an overview of replication: Self replication

31 Nanotechnology is a manufacturing technology The impact depends on the product being manufactured The impact of nanotechnology The Vision

32 We’ll have more computing power in the volume of a sugar cube than the sum total of all the computer power that exists in the world today More than bits in the same volume Almost a billion Pentiums in parallel Powerful Computers The Vision

33 Disease and ill health are caused largely by damage at the molecular and cellular level Today’s surgical tools are huge and imprecise in comparison The Vision Nanomedicine

34 In the future, we will have fleets of surgical tools that are molecular both in size and precision. We will also have computers much smaller than a single cell to guide those tools. The Vision Nanomedicine

35 Killing cancer cells, bacteria Removing circulatory obstructions Providing oxygen (artificial red blood cells) Adjusting other metabolites The Vision Nanomedicine

36 By Robert Freitas, Zyvex Research Scientist Surveys medical applications of nanotechnology Volume I (of three) published in 1999 The Vision Nanomedicine

37 Human impact on the environment depends on Population Living standards Technology The Vision

38 Restoring the environment with nanotechnology Low cost hydroponics Low cost solar power Pollution free manufacturing The Vision

39 Military applications of molecular manufacturing have even greater potential than nuclear weapons to radically change the balance of power. Admiral David E. Jeremiah, USN (Ret) Former Vice Chairman, Joint Chiefs of Staff November 9, The Vision

40 New, inexpensive materials with a strength-to-weight ratio over 50 times that of steel Critical for aerospace: airplanes, rockets, satellites… Useful in cars, trucks, ships,... Lighter, stronger, smarter, less expensive The Vision

41 Space Launch vehicle structural mass could be reduced by a factor of 50 Cost per kilogram for that structural mass could be under a dollar Which will reduce the cost to low earth orbit by a factor 1,000 or more publications/1997/applications/ The Vision

42 Greater function per unit weight Computers and sensors will weigh less per unit mass Greater functionality per pound, further reducing cost per function publications/1997/applications/ The Vision

43 Nanotechnology offers... possibilities for health, wealth, and capabilities beyond most past imaginings. K. Eric Drexler Summation

45 Born-Oppenheimer approximation A carbon nucleus is more than 20,000 times as massive as an electron Assume the atoms (nuclei) are fixed and unmoving, and then compute the electronic wave function If the positions of the atoms are given by r 1, r 2,.... r N then the energy of the system is: E(r 1, r 2,.... r N ) This is fundamental to molecular mechanics Quantum uncertainty

46 Ground state quantum uncertainty σ 2 :positional variance k: restoring force m: mass of particle ħ :Planck’s constant divided by 2 π Quantum uncertainty

47 C-C spring constant:k~440 N/m Typical C-C bond length:0.154 nm σ for C in single C-C bond:0.004 nm σ for electron (same k):0.051 nm Quantum uncertainty A numerical example

48 Basic assumptions Nuclei are point masses Electrons are in the ground state The energy of the system is fully determined by the nuclear positions Directly approximate the energy from the nuclear positions, and we don’t even have to compute the electronic structure Molecular mechanics

49 Example: H 2 Internuclear distance Energy Molecular mechanics

50 Parameters Internuclear distance for bonds Angle (as in H 2 O) Torsion (rotation about a bond, C 2 H 6 Internuclear distance for van der Waals Spring constants for all of the above More terms used in many models Quite accurate in domain of parameterization Molecular mechanics