The strategic astrophysics missions of the coming decades will help answer the questions "How did our universe begin and evolve?" "How did galaxies, stars, and planets come to be?" and "Are we alone?" Enabling these missions requires advances in key technologies far beyond the current state of the art. NASA’s Physics of the Cosmos2 (PCOS), Cosmic Origins3 (COR), and Exoplanet Exploration Program4 (ExEP) Program Offices manage technology maturation projects funded through the Strategic Astrophysics Technology (SAT) program to accomplish such advances. The PCOS and COR Program Offices, residing at the NASA Goddard Space Flight Center (GSFC), were established in 2011, and serve as the implementation arm for the Astrophysics Division at NASA Headquarters. We present an overview of the Programs' technology development activities and the current technology investment portfolio of 23 technology advancements. We discuss the process for addressing community-provided technology gaps and Technology Management Board (TMB)-vetted prioritization and investment recommendations that inform the SAT program. The process improves the transparency and relevance of our technology investments, provides the community a voice in the process, and promotes targeted external technology investments by defining needs and identifying customers. The Programs’ priorities are driven by strategic direction from the Astrophysics Division, which is informed by the National Research Council’s (NRC) "New Worlds, New Horizons in Astronomy and Astrophysics" (NWNH) 2010 Decadal Survey report , the Astrophysics Implementation Plan (AIP)  as updated, and the Astrophysics Roadmap “Enduring Quests, Daring Visions” . These priorities include technology development for missions to study dark energy, gravitational waves, X-ray and inflation probe science, and large far-infrared (IR) and ultraviolet (UV)/optical/IR telescopes to conduct imaging and spectroscopy studies. The SAT program is the Astrophysics Division’s main investment method to mature technologies that will be identified by study teams set up to inform the 2020 Decadal Survey process on several large astrophysics mission concepts.
The James Webb Space Telescope (JWST) - the 21st century follow-on to NASA's highly successful Hubble Space Telescope - has moved one step closer to becoming a reality. In addition to selecting the instrument and science teams, NASA announced on September 10, 2002 that TRW Space and Electronics and its partners - Ball Aerospace and Eastman Kodak - had won the prime contract to build the high-profile observatory, formerly known as the Next Generation Space Telescope. It will be up to the contractor team and NASA to finalize designs and being laying the groundwork for assemblying one of the largest single-aperture telescopes ever flown. This article provides a general overview of the JWST mission - a centerpiece of NASA's Origins Program - and describes some of the technological challenges that NASA and TRW face.
With the discovery of galaxies that existed when the universe was very young, of planets not in our own solar system, and with the tantalizing evidence that he conditions for life may have existed within our solar system on planets or moons outside of the earth system, the pat year has seen an explosion of interest in astronomy. In particular, a new era of exploration and understanding seems imminent, where the connection between the existence for the conditions of life will be connected to the origin of galaxies, stars and planets within the Universe. Who knows where this quest for knowledge will take us.
One of the key charges to NASA's Mission to Planet Earth (MTPE) is to ensure the continuity of future Landsat data. The New Millennium Program's (NMP) first Earth orbiting flight will validate technologies contributing to the reduction in cost of Landsat follow-on missions. The centerpiece is an advanced land imager (ALI) instrument. The EO-1 imaging system will also incorporate alternative and innovative approaches to future land imaging, including two different hyperspectral imaging techniques. One of these is a hyperspectral wedge spectrometer and the other is a miniature hyperspectral grating spectrometer.
We present the preliminary results of a feasibility study performed by a team of scientists and engineers from NASA, academia and industrial concerns. The candidate concept is a deployable 8 meter diameter telescope optimized for the near infrared region (1 - 5 microns), but with instruments capable of observing from the visible all the way to 30 microns. The observatory is radiatively cooled to about 30 K and would be launched on an Atlas II-AS to the Lagrange Point L2.
There is a growing interest in applying the resources of the Tracking and Data Relay Satellite System (TDRSS) as the primary support capability for future small satellite users. This interest is based on a variety of benefits offered by the TDRSS, and not available with globally-distributed space-ground links. An architecture based on an optical augmentation to the current TDRSS space network is discussed, including a candidate design for the user and relay terminals.
A design for an advanced camera (AC) third-generation Hubble Space Telescope scientific instrument is discussed. The AC is a three-channel spectrophotometric camera with wavelength sensitivity from 115-1000 nm. The AC, if selected, would be launched in 1999 for installation on HST. The axial bay design incorporates optical correction for the aberrated HST primary mirror and evolutionary advances in imaging capability.
The study reviews the research and development of a prototype laser used to study one possible method of short-pulse production and amplification, in particular, a pulsed Nd:YAG ring laser pumped by laser diode arrays and injected seeded by a 100-ps source. The diode array pumped, regenerative amplifier consists of only five optical elements, two mirrors, one thin film polarizer, one Nd:YAG crystal, and one pockels cell. The pockels cell performed both as a Q-switch and a cavity dumper for amplified pulse ejection through the thin film polarizer. The total optical efficiency was low principally due to the low gain provided by the 2-bar pumped laser head. After comparison with a computer model, a real seed threshold of about 10 exp -15 J was achieved because only about 0.1 percent of the injected energy mode-matched with the ring.
Some of the tradeoffs involved in selecting a laser source for space-based laser ranging are outlined, and some of the recent developments in the laser field most relevant to space-based lasers for ranging and altimetry are surveyed. Laser pulse width and laser design are discussed. It is argued that, while doubled/tripled ND-host lasers are currently the best choice for laser ranging in two colors, they have the shortcoming that the atmospheric transmission at 355 nm is significantly poorer than it is at longer wavelengths which still have sufficient dispersion for two-color laser ranging. The life requirement appears to demand that laser diode pumping be used for space applications.
Proc. SPIE. 1417, Free-Space Laser Communication Technologies III
KEYWORDS: Signal to noise ratio, Point spread functions, Digital signal processing, Detection and tracking algorithms, Sensors, Calibration, Laser applications, Detector arrays, Telecommunications, Free space optical communications
A proof-of-concept (POC) demonstration system has been developed which demonstrates acquisition, tracking and point-ahead angle sensing for a space optical communications terminal utilizing a single high speed area array detector. The detector is the 128 x 128 pixel Kodak HS-40 photodiode array. It has 64 parallel readout channels and can operate at frames rates up to 40,000 frames/sec with rms readout noise of 20 photoelectrons. A windowing scheme and special purpose digital signal processing electronics are employed to implement acquisition and tracking algorithms. The system operates at greater than 1 kHz sample (frame) rates. Acquisition can be performed in as little as 30 milliseconds with less than 1 picowatt of 0.85 micron beacon power on the detector. At the same power level, the rms tracking accuracy is approximately 1/16 pixel. Results of system analysis and measurements using the POC system are presented.
The main areas of research being conducted at NASA Goddard Space Flight Center are reviewed. Research on transmitter source technology is addressed, emphasizing the development of AlGaAs semiconductor laser diodes. Research on receiver technology is examined, and progress being made in the development of the Pointing, Acquisition, and Tracking System (PATS) is reviewed. Plans for an in-space technology demonstration are briefly discussed.
The transcript proceedings of the panel discussion has been included in this volume to provide a permanent record of the opinions and views of the panel members and the audience participants. It also provides a snap-shot of the status of free-space laser communications and the projections for the future. There were a few difficulties encountered in the compilation of this transcript. It was not possible to include all of the view graphs presented by the speakers. Additionally the quality of the audio recording was less than desirable. Every effort was made to accurately interpret the more garbled sections. lt is hoped that these omissions will not detract form the utility of the text. The panel members are acknowledged for their thoughtful presentations and ensightful discussions. Members of the audience asking questions, who could be identified by the conference chairs, have also been included in the transcript.