HUMAN-AIDED CONSTRUCTION OF A LARGE LUNAR TELESCOPE by Paul van Susante A thesis submitted to the Faculty and the Board of Trustees of the Colorado School of Mines in partial fulfillment of the requirements for the degree of Master of Science (Engineering Systems) Golden, Colorado Date ___________ Signed: ________________________ Paul van Susante Approved: ________________________ Dr. R.H. King Thesis Advisor Golden, Colorado Date ____________ ________________________ Dr. D. Munoz Department Head Division of Engineering ii ABSTRACT The Moon is an excellent platform for operations for astronomical purposes while at the same time it is possible to combine such scientific activities with exploration and resource utilization. The purpose of this NASA-sponsored study was to find out how a large infrared telescope can be built inside a permanently shadowed crater on the Moon using humans and robots, to define the required infrastructure. The results will give NASA a lunar reference to compare to a telescope mission to free-space. The alt-azimuth telescope design will consist of a 25 m diameter segmented primary mirror. The secondary mirror will be 50 meter above the primary and will be supported by three truss structures. It will use super-conducting magnetic bearings and a counterweight / instrument housing. The required infrastructure for constructing this telescope includes space- and surface transportation. A (temporary) lunar base will need to be established and a smaller construction outpost will be required. The surface transportation will consists of robots and a ski-lift-type cable system. Communication links will be needed at Malapert Mountain and at the rim of Shackleton crater to guarantee continuous communications. Power for the telescope and the lunar base will be iii generated at the so-called Peak of Eternal Light and transported using the lift cables. To construct this telescope five different types of robots will be needed and two humans will be supervising the robots during certain phases while the robots will be remotely controlled from the lunar base or from Earth. During this report it is shown that for such large telescopes, it is possible to think of ways to deal with the perceived negative aspects of the Moon such as dust, gravity, temperatures, etc. The choice between free space (Sun-Earth L2) and the lunar surface for a large infrared telescope is not immediately clear. Both locations have advantages and disadvantages. The major advantage of S-E L2 is the possibility to observe the whole universe, while the major advantage of the lunar South Pole is the possibility to operate for many years longer and at the same time allowing easier maintenance and expansion than possible in S-E L2. For a choice it is not only important to look at the possible astronomy, but also to the construction, operations and other factors such as maintenance options, efficiency, expansion possibilities and the support of a larger infrastructure. Many improvements will be required in many technological areas dealing mostly with the capabilities of robots, the extension of operational environment into the extremely cold regions of 40 K, remotely operated performing delicate construction tasks, the creation of infrastructure, the super-conducting magnetic iv bearings in a much larger type and their required three orders of magnitudes increase in precision, but none seem unacceptably far in the future. Next to technology improvements, there is also the need to know more about the lunar local environment such as the dust behavior, the topography with a vertical and horizontal spatial resolution better than one meter, absolute temperature measurements and the temperature fluctuations. Some of these measurements will be done by lunar missions that will reach the Moon in the coming years such as SMART-1, LUNAR-A and SELENE. As far as humans are concerned it will require augmentations in the space-suits of the astronauts, such as enhanced sensors, artificial muscles in the suit and display capabilities in the helmet, to make sure the humans are optimally equipped to handle all situations during the construction process. A change in philosophy will be required in scientists and other involved partners to build and invest in infrastructure instead of going the path of "throw- away" missions every few years. This change in philosophy might prove to be the most difficult of all steps forward. v TABLE OF CONTENTS ABSTRACT .......................................................................................................iii LIST OF FIGURES .............................................................................................xi LIST OF TABLES .............................................................................................xiv LIST OF ABREVIATIONS ................................................................................xvi ACKNOWLEDGEMENTS............................................................................... xviii Chapter 1 INTRODUCTION............................................................................ 1 Chapter 2 SUPPORT INFRASTRUCTURE .................................................... 6 2.1 Transportation to the lunar surface ................................................ 6 2.2 Power generation ........................................................................... 8 2.3 Power storage .............................................................................. 13 2.4 Power transmission...................................................................... 13 2.5 Communication ............................................................................ 15 2.6 Lunar base ................................................................................... 16 2.7 Lift system.................................................................................... 17 2.8 Transportation on the lunar surface ............................................. 20 2.9 Construction site .......................................................................... 22 Chapter 3. STATE OF THE ART OF ROBOTICS IN SPACE & CONSTRUCTION ........................................................................................... 23 3.1 Earth construction robotics........................................................... 23 3.2 Earth mining automation .............................................................. 24 3.3 Space robotics ............................................................................. 25 3.4 Space construction....................................................................... 26 3.5 General research ......................................................................... 27 3.6 Supervised autonomy and teamwork .......................................... 29 vi Chapter 4. THE LUNAR ENVIRONMENT AND ITS RELEVANCE TO TELESCOPE-DESIGN AND OPERATIONS .................................................. 31 4.1 Location topography..................................................................... 31 4.2 Gravity.......................................................................................... 33 4.2.1 Effect of zero- or micro-gravity on a large telescope .......... 33 4.2.2 Deformation of the mirror due to gravity ............................. 34 4.2.3 Vibration generation and damping in the structure ............. 40 4.2.4 Pointing and tracking of the telescope................................ 42 4.2.5 Construction ....................................................................... 43 4.2.6 General influences on engineering ..................................... 44 4.3 Vacuum........................................................................................ 45 4.3.1 No atmospheric absorption................................................. 45 4.3.2 Contamination of the vacuum............................................. 45 4.3.3 Thermal heat rejection........................................................ 46 4.4 Dust.............................................................................................. 46 4.4.1 Contamination of surfaces and sensitive elements............. 47 4.4.2 Wear and tear of moving parts ........................................... 48 4.4.3 Foundation design .............................................................. 48 4.5 Temperature................................................................................. 49 4.5.1 Absolute temperature must be very low ............................. 50 4.5.2 Thermal gradients............................................................... 52 4.5.3 Thermal control................................................................... 52 4.6 Lighting conditions ....................................................................... 53 4.7 Seismicity..................................................................................... 53 4.8 Meteoroid impacts........................................................................ 54 Chapter 5. TELESCOPE DESIGN & DESIGN DECISIONS .......................... 57 5.1 Relevant general parameters for a telescope & its construction .. 57 5.2 Requirements for a large lunar telescope .................................... 65 5.3 Space transportation influences on elements............................... 67 5.4 Optimization of construction elements, transportation and robots 69 vii 5.5 Phases in the construction process.............................................. 69 5.5.1 Main Phases....................................................................... 70 5.5.2 Subphases ........................................................................