Deep Space One
Deep Space 1, an eight foot long spacecraft launched by
NASA in October 1998, is testing new forms of technology
for future deep-space flights. Some of these are:
A self-navigating artificial intelligence system that
lets the spacecraft set its own course which could make
future spacecraft less reliant on orders from Earth;
A radio that can transmit at a higher frequency than most
of today's probes. The frequency, called Ka band, is
expected to speed up communications by four fold over
current transmitters;
An instrument that analyzes charged particles called ions;
An ion propulsion engine that moves the spacecraft by
sending out a stream of high-speed ions, delivering
10 times more thrust than a conventional engine for
a given amount of fuel. That means spacecraft can be
smaller, lighter and less expensive to launch into space.
Deep Space 1 will remain functional when its prime mission
officially ends Sept. 18, and could fly by two comets in
2001 if an extended mission is funded.
Mission Data
LIFTOFF!
October 24, 1998
Deep Space 1 blasted into space at 8:08 a.m. Eastern time
from Cape Canaveral Air Station, FL. The probe separated
from the Delta II launch vehicle about 550 kilometers
(345 miles) above the Indian Ocean and was sent on its way
to test 12 technologies in coming months. All critical
spacecraft systems, such as power, temperature and attitude
control were performing well. The solar arrays and a new
radio transmitter/receiver were validated within the first
two hours after launch. Telemetry was received from the
spacecraft through NASA's Deep Space Network at 1 hour,
37 minutes after launch, and 13 minutes later it was
determined that the spacecraft's two solar arrays had
been deployed.
ION PROPULSION SYSTEM STARTS UP
November 25, 1998
Deep Space 1's ion propulsion drive came on-line yesterday,
MAIN SYSTEMS TEST FINISHED
April 6, 1999
Deep Space 1 has successfully demonstrated most of its new
Testing of two technologies that make the Deep Space 1 less
A robotic navigator, called AutoNav, that will guide the
Two advanced science instruments, a camera/spectrometer
The ion propulsion system has performed flawlessly, logging
COMPUTER PROGRAM ASSUMES SPACECRAFT COMMAND
May 17, 1999
Remote Agent, a new Artificial Intelligence software, has
"Remote Agent can create and carry out its own plans to
Remote Agent features three components:
The Planner/Scheduler, which determines detailed activities
the Executive, which interprets the plans and adds more
Livingstone, a system monitoring program, designed to spot
REMOTE AGENT SUCCESSFUL
June 7, 1999
During the week of May 17, the Remote Agent Artificial
Remote Agent itself provided all the clues for scientists
The result: From 11 a.m. on Monday, May 17th, and in six
The challenges scientists gave Remote Agent were:
On May 17, the spacecraft's camera appeared to be stuck
On May 21, "when the artificial intelligence detected that
Finally, a thruster was simulated stuck in the "off"
.
ION PROPULSION SYSTEM WINS DISCOVER MAGAZINE AWARD
June 22, 1999
Discover magazine's annual awards, now in their 10th year,
The ion drive combines a gas found in photo flash units
The fuel used in Deep Space 1's ion engine is xenon, a
At the rear of the chamber is a pair of metal grids which
At full throttle, the ion engine would consume about 2,500
ASTEROID FLYBY
Thursday, July 29, 1999
Deep Space 1 made the closest flyby ever of an asteroid
CAMERA TRANSMISSION
Saturday, July 31, 1999
Deep Space 1 flew within an estimated 10 miles of the
Visit the Official
Deep Space 1 Website!
and has run smoothly since. The engine started up at 2:53
p.m. Pacific Standard Time in response to commands sent to
the spacecraft. After running overnight in low-thrust mode,
engineers commanded the engine to switch to higher-thrust
modes today. The mission team plans to leave the engine
running over the four-day Thanksgiving weekend.
technologies in space, including the ion engine that is
expected to be 10 times more efficient than conventional
liquid or solid rocket engines, proving they are ready for
use in science missions of the 21st century. Of the dozen
advanced technologies onboard the spacecraft, seven have
completed testing, including the ion propulsion system,
solar array and new technologies in communications,
microelectronics and spacecraft structures.
reliant on humans is 75 percent complete, while testing of
a third is scheduled to begin in May:
spacecraft to a rendezvous with asteroid 1992 KD on July
29 without active human control from the Earth;
and an instrument that studies electrically charged
particles emitted by the Sun and other sources, are on
schedule, having finished 75 percent of their tests;
more than 1,300 hours of operation.
been operating NASA's Deep Space 1 mission and its new ion
engine since 11 a.m. Pacific Daylight Time today. The big
question: Can a spacecraft function entirely on its own
nearly 120 million kilometers (75 million miles) from Earth,
without detailed instructions from the ground?
achieve the mission goals that we give it," said Dr. Doug
Bernard, Remote Agent manager at NASA's Jet Propulsion
Laboratory, Pasadena, CA. "This technology could allow
us to pursue solar system exploration missions that only
a few years ago would have been considered too elaborate,
too costly or excessively dependent on teams of Earth-bound
controllers."
needed to achieve general goals;
detail to them, then issues commands to the flight software,
coordinating the three parts of Remote Agent;
problems and inform the Executive program, which then acts
to correct the problem if possible, or wait for help from
Earth if it is too difficult for its' limited parameters.
Intelligence program passed all of the tests put to it,
including aiding in the correction a real glitch that was
not part of the test. This occurred when the system fired
the ion engine on but failed to turn it back off due to
some type of computer bug.
to diagnose and resolve the problem precisely. The program
provided a list of possible reasons for the bug, which the
scientists at NASA's Ames Research Center found was related
to a timing error during an exchange of information between
system components. Said computer scientist Nicola Muscettola,
"After defining the bug, our experiment team was confident
we could complete the flight test. We asked Remote Agent to
develop a new plan and then to fly Deep Space 1 solo for six
more hours."
hours on Friday, May 21, the remote agent team met 100
percent of their experiment objectives. "If had not been
for Remote Agent's ability to do onboard planning, we
would not have been able to complete the tests so quickly.
It would have taken days for the ground team to come up with
a new plan," said Dr. Pandu Nayak, deputy manager of Remote
Agent development at Ames.
in the "on" position. Remote Agent formulated a new plan
that accounted for the fact that the camera could not be
turned off, thus impacting total power availability.
an electronics unit had 'failed,' the software fixed the
unit by reactivating it, not unlike rebooting a personal
computer after the screen freezes," said Dr. Marc Rayman,
Deep Space 1 deputy mission manager and chief mission
engineer at JPL, Pasadena, CA. "Next, a sensor 'failed,'
and Remote Agent correctly recognized the sensor was the
problem, not the device it was sensing. In each case, Remote
Agent correctly distinguished which situation it was in."
position, which Remote Agent detected and for which it
compensated by switching to a different set of thrusters.
recently honored NASA's Solar Electric Propulsion Technology
Application Readiness (NSTAR) program team for development
of the ion propulsion system powering Deep Space 1. Accepting
on behalf of the team was former NSTAR manager Jack Stocky
of NASA's Jet Propulsion Laboratory, Pasadena, CA.
with some of the technologies that make television picture
tubes work to deliver a thrust only no stronger than the
pressure of a sheet of paper resting on the palm of a hand.
Despite this, the engine, for a given amount of fuel, can
increase a spacecraft's velocity 10 times more than can a
conventional liquid or solid fuel rocket.
colorless, odorless and tasteless gas more than 4-1/2
times heavier than air. When the ion engine is running,
electrons are emitted from a cathode into a chamber ringed
by magnets. The electrons strike atoms of xenon, knocking
away one of the 54 electrons orbiting each atom's nucleus.
This leaves each atom one electron short, giving it a net
positive charge, creating an ion.
are charged positive and negative, respectively, with up
to 1,280 volts of electric potential. The force of this
electric charge exerts a strong "electrostatic" pull on
the xenon ions causing the ions to shoot past at a speed
of more than 100,000 kilometers per hour (60,000 miles per
hour), continuing right on out the back of the engine and
into space.
watts of electrical power and put out 90 millinewtons
(1/50th of a pound) of thrust. This is compares to the
force exerted by a single sheet of paper resting on the
palm of a hand.
and apparently misaimed its camera about 20 minutes before
the 35,000 mph encounter and failed to get any close-ups
of the giant orbiting rock, disappointing scientists.
The probe flew within about 10 miles of the Asteroid
Braille on Wednesday night, but the pictures it sent back
show only empty space, said Robert Nelson, project scientist
at NASA's Jet Propulsion Laboratory. "This is analogous to
mispointing a camera and getting a blank field of view."
Asteroid Braille on Wednesday, began transmitting data
from its infrared camera on Friday, NASA's Jet Propulsion
Laboratory said. Four black-and-white images were taken
by the spacecraft's camera - two about 70 minutes before
its closest approach and two of lesser quality about 15
minutes after the encounter more than 117 million miles
from Earth. The probe didn't capture close-ups because
of a failure to aim the spacecraft's camera correctly.
Pictures sent back showed only empty space.
