[meteorite-list] Lasers Could Give Space Research its 'Broadband' Moment

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 16 Feb 2017 14:25:19 -0800 (PST)
Message-ID: <201702162225.v1GMPJ19020344_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?feature=6746

Lasers Could Give Space Research its 'Broadband' Moment
Jet Propulsion Laboratory
February 14, 2017

Thought your Internet speeds were slow? Try being a space scientist for
a day.

The vast distances involved will throttle data rates to a trickle. You're
lucky if a spacecraft can send more than a few megabits per second (Mbps).

But we might be on the cusp of a change. Just as going from dial-up to
broadband revolutionized the Internet and made high-resolution photos
and streaming video a given, NASA may be ready to undergo a similar "broadband"
moment in coming years.

The key to that data revolution will be lasers. For almost 60 years, the
standard way to "talk" to spacecraft has been with radio waves, which
are ideal for long distances. But optical communications, in which data
is beamed over laser light, can increase that rate by as much as 10 to
100 times.

High data rates will allow researchers to gather science faster, study
sudden events like dust storms or spacecraft landings, and even send video
from the surface of other planets. The pinpoint precision of laser communications
is also well suited to the goals of NASA mission planners, who are looking
to send spacecraft farther out into the solar system.

"Laser technology is ideal for boosting downlink communications from deep
space," said Abi Biswas, the supervisor of the Optical Communications
Systems group at NASA's Jet Propulsion Laboratory, Pasadena, California.
"It will eventually allow for applications like giving each astronaut
his or her own video feed, or sending back higher-resolution, data-rich
images faster."

Science at the speed of light

Both radio and lasers travel at the speed of light, but lasers travel
in a higher-frequency bandwidth. That allows them to carry more information
than radio waves, which is crucial when you're collecting massive amounts
of data and have narrow windows of time to send it back to Earth.

A good example is NASA's Mars Reconnaissance Orbiter, which sends science
data at a blazing maximum of 6 Mbps. Biswas estimated that if the orbiter
used laser comms technology with a mass and power usage comparable to
its current radio system, it could probably increase the maximum data
rate to 250 Mbps.

On Earth, data is sent over far shorter distances and through infrastructure
that doesn't exist yet in space, so it travels even faster.

Increasing data rates would allow scientists to spend more of their time
on analysis than on spacecraft operations.

"It's perfect when things are happening fast and you want a dense data
set," said Dave Pieri, a JPL research scientist and volcanologist. Pieri
has led past research on how laser comms could be used to study volcanic
eruptions and wildfires in near real-time. "If you have a volcano exploding
in front of you, you want to assess its activity level and propensity
to keep erupting. The sooner you get and process that data, the better."

That same technology could apply to erupting cryovolcanoes on icy moons
around other planets. Pieri noted that compared to radio transmission
of events like these, "laser comms would up the ante by an order of magnitude."

Clouding the future of lasers

That's not to say the technology is perfect for every scenario. Lasers
are subject to more interference from clouds and other atmospheric conditions
than radio waves; pointing and timing are also challenges.

Lasers also require ground infrastructure that doesn't yet exist. NASA's
Deep Space Network, a system of antenna arrays located across the globe,
is based entirely on radio technology. Ground stations would have to be
developed that could receive lasers in locations where skies are reliably
clear.

Radio technology won't be going away. It works in rain or shine, and will
continue to be effective for low-data uses like providing commands to
spacecraft.

Next steps

Two upcoming NASA missions will help engineers understand the technical
challenges involved in conducting laser communications in space. What
they'll learn will advance lasers toward becoming a common form of space
communication in the future.

The Laser Communications Relay Demonstration (LCRD), led by NASA's Goddard
Space Flight Center in Greenbelt, Maryland, is due to launch in 2019.
LCRD will demonstrate the relay of data using laser and radio frequency
technology. It will beam laser signals almost 25,000 miles (40,000 kilometers)
from a ground station in California to a satellite in geostationary orbit,
then relay that signal to another ground station. JPL is developing one
of the ground stations at Table Mountain in southern California. Testing
laser communications in geostationary orbit, as LCRD will do, has practical
applications for data transfer on Earth.

Deep Space Optical Communications (DSOC), led by JPL, is scheduled to
launch in 2023 as part of an upcoming NASA Discovery mission. That mission,
Psyche, will fly to a metallic asteroid, testing laser comms from a much
greater distance than LCRD.

The Psyche mission has been planned to carry the DSOC laser device onboard
the spacecraft. Effectively, the DSOC mission will try to hit a bullseye
using a deep space laser -- and because of the planet's rotation, it will
hit a moving target, as well.

http://go.nasa.gov/2gBzbyx

UPDATED AT 10:40 a.m. PST on 2/15/17 to clarify relative data speeds.

News Media Contact
Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good at jpl.nasa.gov

2017-036
Received on Thu 16 Feb 2017 05:25:19 PM PST