NASA has selected three proposals, including one from NASA’s Jet Propulsion Laboratory in Pasadena, Calif., as Technology Demonstration Missions to transform space communications, deep space navigation and in-space propulsion capabilities. The projects will develop and fly a space solar sail, deep space atomic clock, and space-based optical communications system.
NASA will fly the Laser Communications Relay demonstration mission within 4 years. They will fly and validate a reliable, capable, and cost-effective optical communications technology. Optical communications technology provides data rates up to 100 times higher than today’s systems, which will be needed for future human and robotic space missions. The technology is directly applicable to the next generation of NASA’s space communications network. After the demonstration, the developed space and ground assets will be qualified for use by near-Earth and deep space missions requiring high bandwidth and a small ground station reception area.
Data rates 10-100 times more capable than current RF systems will allow greatly improved connectivity and enable a new generation of remote scientific investigations as well as provide the satellite communication’s industry with disruptive technology not available today. Space laser communications will enable missions to use bandwidth-hungry instruments, such as hyperspectral imagers, synthetic aperture radar (SAR), and other instruments with high definition in spectral, spatial, or temporal modes. Laser communication will also make it possible to establish a “virtual presence” at a remote planet or other solar system body, enabling the high-rate communications required by future explorers.
As an example, at the current limit of 6 Mbps for the Mars Reconnaissance Orbiter (MRO), it takes approximately 90 minutes to transmit a single HiRISE high resolution image back to earth. In some instances, this bottleneck can limit science return. An equivalent MRO mission outfitted with an optical communications transmitter would have a capacity to transmit data back to earth at 100 Mbps or more, reducing the single image transmission time to on order of 5 minutes.
A Deep Space Atomic Clock demonstration mission will fly and validate a miniaturized mercury-ion atomic clock that is 10-times more accurate than today’s systems. This project will demonstrate ultra-precision timing in space and its benefits for one-way radio navigation. The investigation will fly as a hosted payload on an Iridium spacecraft and make use of GPS signals to demonstrate precision orbit determination and confirm the clock’s performance. Precision timing and navigation is critical to the performance of a wide range of deep space exploration missions.
The device ‘swooshing’ into a satellite is the vacuum tube, one of the main components of an atomic clock that will undergo a technology flight demonstration.
The Deep Space Atomic Clock (DASC) demonstration will enable numerous opportunities for navigation and science enhancements, new missions, and mission cost savings, including:
* Increase Data Quantity: A factor of 2 to 3 increase in navigation and radio science data quantity by allowing coherent tracking to extend over the full view period of Earth stations.
* Improve Data Quality: Up to 10 times more accurate navigation, gravity science, and occultation science at remote solar system bodies by using one-way radiometric links.
* Enabling New Missions: Shift towards a more flexible and extensible one-way radio navigation architecture enabling development of capable in-situ satellite navigation systems and autonomous deep space radio navigation.
* Reduce Proposed Mission Costs: Reduce mission costs for using the Deep Space Network (DSN) through aperture sharing and one-way downlink only time.
* Benefits to GPS: Improve clock stability of the next GPS system by 100 times.
One example of the benefits possible for future missions is illustrated by considering a follow on replacement to the Mars Reconnaissance Orbiter (MRO) outfitted with a DSAC. Such a system could avoid the current MRO reliance on two-way coherent tracking using the DSN to perform orbital determination, freeing the usage of DSN for one-way downlink only time to transmit scientific data. This would amount to an $11M reduction in just the network operational costs, as well as a 100% increase in the amount of usable downlinked gravity science and navigation data.
A Solar Sail demonstration mission will deploy and operate a sail area 7 times larger than ever flown in space. It is potentially applicable to a wide range of future space missions, including an advanced space weather warning system to provide more timely and accurate notice of solar flare activity. This technology also could be applied to economical orbital debris removal and propellant-less deep space exploration missions. The National Oceanic and Atmospheric Administration is collaborating with NASA and L’Garde Inc. on the demonstration.
The Solar Sail demonstration will:
* Demonstrate the deployment of a 38 meters x 38 meters solar sail in space (quadrupling the area of the largest sail deployed and tested on the ground of 20m x 20m by L’Garde at NASA’s Plumbrook facility in Ohio).
* Demonstrate attitude control plus passive stability and trim using beam-tip vanes.
* Execute a navigation sequence with mission-capable accuracy.
The clock and solar sail will be ready for flight in three years. The optical communications team anticipates it will take four years to mature the technology for flight.