ALAT

Airborne Large Aperture Telescope


Jeffrey R. Charles



Copyright 1993, 1994, 1995, 1996, Jeffrey R. Charles, All Rights Reserved.

Document converted to HTML on June 12, 1996.
Drawing files are not posted.
When posted, drawing files will total ~1 megabyte.


Instrumentation and applications relating to an airborne large aperture telescope which is envisioned to reside on a multiple function lighter than air platform, as presented at the JPL Advanced Concepts Program Mini conference for "Innovative Space Mission Applications for Thin Films and Fabrics" on May 8, 1995 and published in the proceedings. ALAT was first presented as part of my ARDOC (Airborne Relay for Deep-Space Optical Communication) presentation at JPL's "Seminar 331" on December 8, 1993. Some data from the earlier presentation has been added to this file. Even though this material was presented at JPL and subsequently proposed for JPL/NASA Project(s), it was all conceived and developed with my own time and resources.

Contents:

  1. ALAT. Airborne Large Aperture Telescope; Abstract
  2. Thin Film / Fabric Structural Material Application Concept Summary; Objectives
  3. Benefits of a Multiple Function LTA Platform; summary of payload capabilities
  4. Performance features
  5. Design Characteristics
  6. Environment
  7. Major Structural / Material / System Challenges:
  8. Proposed Payloads & their Locations on the ALAT Platform.
  9. Disadvantages of a Large LTA Platform.
  10. What else is being done or proposed now?
  11. Additional "Spin-off" Technology & Applications.
  12. Illustrations of Concept Development of and "Spin-off" Applications.



-1-

ALAT

Airborne Large Aperture Telescope

ABSTRACT


A multiple function telescope for astronomical observation and other applications, residing on a multiple function lighter than air platform which is also suitable for:

ARDOC - Airborne Relay for Deep-Space Optical Communication

STRATOCOM (TM) - Stratospheric Observation and Communication

HOST - High Precision Orbital Debris and Satellite Tracking

HIAA - High Resolution Imaging and Astrometry of Asteroids

Instrumentation and applications to be proposed for JPL/NASA Project(s)

Investigator: Jeffrey R. Charles

Abstract for ALAT & Related Concepts:

A multiple function lighter than air robotic platform which is capable of residing in the lower stratosphere for an extended period of time would be an elegant solution for a variety of long standing research and communications problems. Such a platform would be invaluable to the continued pursuit of many disciplines, including astrophysics, high resolution imaging and ranging of satellites and orbital debris, air and space communications utilizing weather dependent frequencies (including optical), atmospheric research, commercial broadcasting, cellular communications, regional position information (including "smart maps" for automobiles), and surveillance. The platform can house inflatable structures which would serve both as ballonets and as reflectors for power collection, communications, and radio astronomy. Additionally, the platform could be used for educational payloads and as a high altitude test bed for materials and instrumentation.

The Airborne Large Aperture Telescope (ALAT) is envisioned to be a multiple function optical telescope (or series of telescopes) which will reside on a high altitude lighter than air robotic platform. The large aperture (~2-3 m) of the telescope and the altitudes at which it operates (~16-22 km) will allow it to perform nearly as well as a space based telescope, yet have many additional advantages, including lower cost, accessibility for maintenance & upgrading, the ability to perform long integrations over a large portion of the sky, and mobility to facilitate strategic positioning for specific events such as eclipses, occultations, or communications. ALAT is the cost effective way to provide the high performance telescopes required for expanded research on a global scale.

Copyright 1993, 1994, 1995, 1996, Jeffrey R. Charles, All Rights Reserved


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-2-

ALAT

Thin Film / Fabric Structural Material Application Concept Summary

Objectives:


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-3-

Benefits of a Multiple Function LTA Platform:

MULTIPLE FUNCTIONS = LESS COST PER FUNCTION, ENABLING MORE CUSTOMERS TO AFFORD TO IMPLEMENT THEIR PROGRAMS, SUCH AS:
  • Astronomical observation, benefiting astrophysics.
  • Optical space communication relay (ARDOC) benefiting space missions, military.
  • High resolution imaging/ranging of satellites & debris, benefiting space missions and the military.
  • High altitude atmospheric & environmental observation, benefiting everyone.
  • Optical and other surveillance, benefiting the police, DEA, military.
  • Forestry, mapping, etc., benefiting civil development and the environment.
  • Security of optical transmissions, benefiting the police and military.
  • Public cellular communications, benefiting everyone.
  • Public broadcasting, benefiting everyone.
  • Deep space RF applications (using inflatable communication & observation reflectors) benefiting astrophysics (space missions & radio astronomy).
  • Beamed power development and use, benefiting communications, scientific research, and travel.
  • Regional position reference (smart maps, etc.) benefiting motorists, police.

  • Return to ALAT Table of Contents



    -4-

    PERFORMANCE FEATURES



    -4a-

    Performance Features;
    Multiple Function Lighter Than Air Platform:
    Why Use a Lighter Than Air Platform?


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    -4b-

    Performance features;
    Why an Airship Instead of a Conventional Balloon?


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    -4c-

    Performance Features;
    Airborne Large Aperture Telescope


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    -4d-

    Airborne Large Aperture Telescope &
    LTA Platform;
    Combined Performance Features & Specifications


    Return to ALAT Table of Contents



    -5-

    Thin Film / Fabric Structural Material Application Concept Summary, continued:

    Design Characteristics


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    -6-

    Thin Film / Fabric Structural Material Application Concept Summary, continued:

    Environment Description:


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    -7-

    CHALLENGES



    -7a-

    Major Structural / Material / System Challenges

    Design:


    Return to ALAT Table of Contents



    -7b-

    Major Structural / Material / System Challenges

    Materials:


    Return to ALAT Table of Contents



    -7c-

    Major Structural / Material / System Challenges

    Demonstration, phase 1:

    Ground based demonstration & materials testing


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    -7d-

    Major Structural / Material / System Challenges

    Demonstration, phase 2:

    Limited airborne demonstration


    Return to ALAT Table of Contents



    -7e-

    High Resolution Imaging and
    Air to Retroreflector Satellite Demonstration Hardware:


    Return to ALAT Table of Contents



    -7f-

    Simplified Experimental Imaging, Tracking, & Optical Communication Demonstration:

    The demonstration will ultimately involve imaging of astronomical and terrestrial objects with small telescopes from an airborne platform. To demonstrate feasibility of an airborne relay for deep-space optical communication, or ARDOC, satellite tracking and a simplified air-space optical communication demonstration will follow. Active space borne optical communication systems are not readily available; therefore, a passive space borne retroreflector (such as that on Lageos) will be utilized for the near term. As necessary studies are completed and a platform has been selected that is compatible with fiscal and mission requirements, it is envisioned that a small scale system test would progress as follows:


    Return to ALAT Table of Contents



    -8-

    Proposed Payloads & their Locations on the Actual Multiple Function ALAT Platform:


    Return to ALAT Table of Contents



    -9-

    Disadvantages of a large lighter than air "airship" platform:


    Return to ALAT Table of Contents



    -10-

    What Else is Being Done or Proposed Now?


    Return to ALAT Table of Contents



    -11-

    Additional "Spin-off" Technology and Applications:


    Return to ALAT Table of Contents



    -12-

    Illustrations:


    The following illustrations show the development of the concept and related "spin-off" technology. To allow a long mission duration and minimize boundary layer effects on the payload, all airborne embodiments utilize lighter than air platforms.

    Airplanes with adequate lift require substantial power and forward air speed in order to fly. This causes undesirable boundary layer effects and makes the aircraft more difficult to track; and tracking can be important for optical and some other communications, or in beaming power. Flying rotors (variants of the helicopter) can remain in a fixed location but can require a lot of power. The necessity to "de-spin" the payload on a flying rotor also adds complexity.

    Since the stability of the telescope is very important, it is either attached to the airship structure or suspended below widely separated support points. The concept has evolved considerably since conception, resulting in "spin-off" applications and technology that will benefit other fields. The drawing and illustration list is shown below.

    All illustrations are under construction, so the drawing files are not posted. When posted, each drawing file will be about 120K.

    1. Illustration of the ALAT Platform***
    2. Illustration of ARDOC (Airborne Relay for Deep-Space Optical Communication)***
    3. Original ALAT Conceptual Drawing; Arrayable LTA (Lighter Than Air) Platform Unit with Telescope***
    4. Second Conceptual Drawing; LTA Platform with Multiple Payloads***
    5. Third Conceptual Drawing; LTA Platform with Internal Inflatable Reflector***
    6. Detail of Steerable Feed Inflatable Antenna Concept***
    7. Ground Based Steerable Feed Antenna with 110 deg. Fully Illuminated Scan Range (based on inflatable version)***
    8. Ground Based Steerable Feed Antenna with Limited Scan Range***
    9. Airborne or Spaceborne Inflatable Antenna with Inflatable Spherical Enclosure***
    10. Large Ground Based Inflatable Antenna with Inflatable Spherical Enclosure under an Inflatable Dome Housing***



    Do you need creative solutions for your engineering, motion picture, or other project? Jeffrey R. Charles performs systems engineering, conceptual design, and technical writing for a variety of applications. In addition, Jeff can provide science consulting in regard to total solar eclipse phenomena, and engineering consulting for optical instrumentation. Please direct inquiries to Jeffrey R. Charles jcharles@versacorp.com or click here for more information.

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