Engineering topics

Cornwell, Donald M.

Publications and source records attributed to Cornwell, Donald M..

6 records

NASA NTRS2018

Toward a NASA Deep Space Optical Communications System

As discussed at SpaceOps in 2016, we expect the data rates from deep space missions to increase approximately one order of magnitude per decade for the next 50 years. The first order of magnitude improvement will come from existing plans for radio frequency (RF) communications including enhancements to both spacecraft and Deep Space Network (DSN) facilities. The next two orders of magnitude are predicted to come from the introduction of deep space optical communications. Studies indicate that optical receive apertures of between 8m12m are desired. The large cost of dedicated receive telescopes makes this method unrealistic – at least in the near-term. The cost of large optical ground terminals is driven primarily by the cost of the optics and by the cost of a stable structure for the telescope. We propose a novel hybrid design in which existing DSN 34m beam waveguide (BWG) radio antennas can be modified to include an 8m equivalent optical primary. By utilizing a low-cost segmented spherical mirror optical design, pioneered by the optical astronomical community, and by exploiting the already existing extremely stable large radio aperture structures in the DSN, we can minimize both of these cost drivers for implementing large optical communications ground terminals. Two collocated hybrid RF/optical antennas could be arrayed to synthesize the performance of an 11.3m receive aperture to support more capable or more distant space missions or used separately to communicate with two optical spacecraft simultaneously. NASA is in the midst of building six new 34m BWG antennas in the DSN. The final two are planned to be built at the DSN Goldstone, California and Canberra complexes. We are now investigating building these last two antennas as RF/optical hybrids. By delaying their operational dates by two years, we would be able to add the 8m optical receive capability for these two antennas while fitting within existing budgetary constraints. This paper describes the hybrid antenna design, the technical challenges being addressed, and plan for using this concept, together with ongoing work on optical flight terminals, to infuse operation optical communications into deep space missions.

Cornwell, Donald M.↗

NASA NTRS2016

Enabling Communication and Navigation Technologies for Future Near Earth Science Missions

In 2015, the Earth Regimes Network Evolution Study (ERNESt) Team proposed a fundamentally new architectural concept, with enabling technologies, that defines an evolutionary pathway out to the 2040 timeframe in which an increasing user community comprised of more diverse space science and exploration missions can be supported. The architectural concept evolves the current instantiations of the Near Earth Network and Space Network through implementation of select technologies resulting in a global communication and navigation network that provides communication and navigation services to a wide range of space users in the Near Earth regime, defined as an Earth-centered sphere with radius of 2M Km. The enabling technologies include: High Rate Optical Communications, Optical Multiple Access (OMA), Delay Tolerant Networking (DTN), User Initiated Services (UIS), and advanced Position, Navigation, and Timing technology (PNT). This paper describes this new architecture, the key technologies that enable it and their current technology readiness levels. Examples of science missions that could be enabled by the technologies and the projected operational benefits of the architecture concept to missions are also described.

Networking↗

NASA NTRS2016

Deep Space Network: the Next 50 Years

In 2014, NASA’s Deep Space Network (DSN) celebrated its 50th year of enabling exploration of the Moon, Solar System planets, and beyond. During those 50 years, the DSN has grown along with the associated spacecraft flight systems, providing some 13 orders of magnitude communications systems improvement. It has also contributed to many of the world’s most important scientific discoveries and provided substantial technological spinoffs that have become part of everyday life on Earth. Studies of the next 25 years indicate that deep space missions will need an order of magnitude increased communications performance per decade - and this is likely to continue beyond that time. As exhibited by this meeting, another major change happening right now is the emergence of a standardized international community for tracking deep space missions. The future definitely involves increased international cooperation. This paper explains the near term plans already underway for the DSN. We also consider the plans and possibilities for deep space optical communications. Finally, we will discuss opportunities for international participation in the next 50 years of deep space exploration.

Deutsch, Leslie J.↗

NASA NTRS2016

Deep Space Network: The Next 50 Years

In 2014, NASA’s Deep Space Network (DSN) celebrated its 50th year of enabling exploration of the Moon, Solar System planets, and beyond. During those 50 years, the DSN has grown along with the associated spacecraft flight systems, providing some 13 orders of magnitude communications systems improvement. It has also contributed to many of the world’s most important scientific discoveries and provided substantial technological spinoffs that have become part of everyday life on Earth. Studies of the next 25 years indicate that deep space missions will need an order of magnitude increased communications performance per decade – and this is likely to continue beyond that time. As exhibited by this meeting, another major change happening right now is the emergence of a standardized international community for tracking deep space missions. The future definitely involves increased inter-national cooperation. This paper explains the near term plans already underway for the DSN. We also consider the plans and possibilities for deep space optical communications. Finally, we will discuss opportunities for international participation in the next 50 years of deep space exploration.

Deutsch, Leslie J.↗

NASA NTRS2015

NASA's Optical Communications Program for 2015 and Beyond

NASA's Space Communications and Navigation (SCaN) program at NASA headquarters is pursuing a vibrant and wide-ranging optical communications program for further planetary and near-Earth missions following the spectacular success of NASA's Lunar Laser Communication Demonstration (LLCD) from the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft orbiting the moon in 2013. This invited paper will discuss NASA's new laser communication missions, key scenarios and details, and the plans to infuse this new technology into NASA's existing communications networks.

Communications↗

NASA NTRS1998

Reference Interferometer Using a Semiconductor Laser/LED Reference Source in a Cryogenic Fourier-Transform Spectrometer

A combination of a single mode AlGaAs laser diode and broadband LED was used in a Michelson interferometer to provide reference signals in a Fourier transform spectrometer, the Composite Infrared Spectrometer, on the Cassini mission to Saturn. The narrowband light from the laser produced continuous fringes throughout the travel of the interferometer, which were used to control the velocity of the scan mechanism and to trigger data sampling. The broadband light from the LED produced a burst of fringes at zero path difference, which was used as a fixed position reference. The system, including the sources, the interferometer, and the detectors, was designed to work both at room temperature and instrument operating temperature of 170 Kelvin. One major challenge that was overcome was preservation, from room temperature to 170 K, of alignment sufficient for high modulation of fringes from the broadband source. Another was the shift of the source spectra about 30 nm toward shorter wavelengths upon cooldown.

Martino, Anthony J.↗