. 24/7 Space News .
IRON AND ICE
Navigating NASA's first mission to the Trojan asteroids
by Tamsyn Brann for GSFC News
Greenbelt MD (SPX) Dec 21, 2018

"The maneuvers to correct Lucy's trajectory are all going to be really critical because the spacecraft must encounter the Trojan at the intersection of the spacecraft and Trojan orbital planes," Stanbridge said. "Changing the spacecraft orbital plane requires a lot of energy, so the maneuvers need to be executed at the optimal time to reach to next body while minimizing the fuel cost."

In science fiction, explorers can hop in futuristic spaceships and traverse half the galaxy in the blink of a plot hole. However, this sidelines the navigational acrobatics required in order to guarantee real-life mission success.

In 2021, the feat of navigation that is the Lucy mission will launch. To steer Lucy towards its targets doesn't simply involve programming a map into a spacecraft and giving it gas money - it will fly by six asteroid targets, each in different orbits, over the course of 12 years.

Lucy's destination is among Jupiter's Trojan asteroids, clusters of rocky bodies almost as old as the Sun itself, and visiting these asteroids may help unlock the secrets of the early solar system. Lucy will encounter a Main Belt asteroid in 2025, where it will conduct a practice run of its instruments before encountering the first four Trojan targets from 2027-2028. In 2033, Lucy will end its mission with a study of a binary system of two Trojans orbiting each other.

Getting the spacecraft where it needs to go is a massive challenge. The solar system is in constant motion, and gravitational forces will pull on Lucy at all times, especially from the targets it aims to visit. Previous missions have flown by and even orbited multiple targets, but none so many as will Lucy.

Scientists and engineers involved with trajectory design have the responsibility of figuring out that route, under Flight Dynamics Team Leader Kevin Berry of NASA's Goddard Space Flight Center in Greenbelt, Maryland. One such engineer is Jacob Englander, the optimization technical lead for the Lucy mission.

"There are two ways to navigate a mission like Lucy," he said. "You can either burn an enormous amount of propellant and zig-zag your way around trying to find more targets, or you can look for an opportunity where they just all happen to line up perfectly." To visit these aligned targets, the majority of Lucy's high-speed lane changes will come from gravity assists, with minimal use of fueled tweaks.

Though Lucy is programmed to throw itself out into a celestial alignment that will not occur for decades, it cannot be left to its own devices. Once the spacecraft begins to approach its asteroid targets, optical navigation is the next required step.

"OpNav," as optical navigation technical lead Coralie Adam refers to it, is the usage of imagery from the on-board cameras to determine Lucy's position relative to the target. This is a useful measurement used by the navigation team to tweak Lucy's route and ensure it stays on the nominal flyby path. Adam works in Simi Valley, California, with KinetX, the company NASA selected to conduct Lucy's deep space navigation.

By using the communications link from the spacecraft to Earth, Adam said, the Lucy team gets information about the spacecraft's location, direction and velocity. The spacecraft takes pictures and sends them down to Earth, where Adam and other optical navigators use software to determine where the picture was taken based on the location of stars and the target.

The orbit determination team uses this data along with data from the communications link to solve for where the spacecraft is and where it is expected to be, relative to the Trojans. The team then designs a trajectory correction maneuver to get Lucy on track.

"The first maneuver is tiny," said navigation technical lead Dale Stanbridge, who is also of KinetX. "But the second one is at 898 meters per second. That's a characteristic of Lucy: very large delta V maneuvers." Delta V refers to the change in speed during the maneuver.

Communicating all of these navigation commands with Lucy is a process all on its own. "Lockheed Martin sends the commands to the spacecraft via the Deep Space Network," Adam said. "What we do is we work with Lockheed and the Southwest Research Institute, where teams are sequencing the instruments and designing how the spacecraft is pointed, to make sure Lucy takes the pictures we want when we want them."

"The maneuvers to correct Lucy's trajectory are all going to be really critical because the spacecraft must encounter the Trojan at the intersection of the spacecraft and Trojan orbital planes," Stanbridge said. "Changing the spacecraft orbital plane requires a lot of energy, so the maneuvers need to be executed at the optimal time to reach to next body while minimizing the fuel cost."

While Lucy is conducting deep space maneuvers to correct its trajectory toward its targets, communications with the spacecraft are sometimes lost for brief periods. "Blackout periods can be up to 30 minutes for some of our bigger maneuvers," Stanbridge said. "Other times you could lose communications would be when, for example, the Sun, comes between the Earth tracking station and the spacecraft, where the signal would be degraded by passing through the solar plasma."

Losing contact isn't disastrous, though. "We have high-fidelity predictions of the spacecraft trajectory which are easily good enough to resume tracking the spacecraft when the event causing a communication loss is over," Stanbridge said.

What route will Lucy take once its mission is complete, nearly 15 years from now? "We're just going to leave it out there," Englander said. "We did an analysis to see if it passively hits anything, and looking far into the future, it doesn't." The Lucy team has given the spacecraft a clear path for thousands of years, long after Lucy has rewritten the textbooks on our solar system's history.

The Lucy mission is led by Principal Investigator Dr. Hal Levison from Southwest Research Institute in Boulder, Colorado. NASA Goddard in Greenbelt, Maryland, manages the mission. Lockheed Martin Space in Denver will build the spacecraft and conduct mission operations.


Related Links
Lucy Asteroid Mission
Asteroid and Comet Mission News, Science and Technology


Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Monthly Supporter
$5+ Billed Monthly


paypal only
SpaceDaily Contributor
$5 Billed Once


credit card or paypal


IRON AND ICE
Space telescope detects water in a number of asteroids
Kobe, Japan (SPX) Dec 19, 2018
Using the infrared satellite AKARI, a Japanese research team has detected the existence of water in the form of hydrated minerals in a number of asteroids for the first time. This discovery will contribute to our understanding of the distribution of water in our solar system, the evolution of asteroids, and the origin of water on Earth. The findings were made by the team led by the Project Assistant Professor Fumihiko Usui (Graduate School of Science, Kobe University), the Associate Senior Researc ... read more

Comment using your Disqus, Facebook, Google or Twitter login.



Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

IRON AND ICE
Roscosmos Chief Could Visit US in Early 2019, NASA Working on Sanctions Waiver

Russian Cosmonaut Dismisses Rumours About ISS Crew, Hole in Soyuz Spaceship

Investigators to Question Russia Cosmonauts Amid ISS 'Hole' Probe

NASA astronaut, crewmates return to Earth after 197-Day mission in space

IRON AND ICE
Arianespace supports Drance and European defense with launch of CSO-1

SpaceX blasts off powerful GPS satellite for US military

Russia to Complete Flight Tests of Soyuz-2.1V Carrier Rocket in 2019 - Source

Roscosmos selects super-heavy rocket concept designed for lunar flights

IRON AND ICE
InSight places its first instrument on Mars

InSight Engineers Have Made a Martian Rock Garden

Opportunity team performs more frequent communication attempts throughout each day

Planetary scientists assist in capturing image of Insight from orbit

IRON AND ICE
China launches first Hongyun project satellite

China's Chang'e-4 probe enters lunar orbit

China launches rover for first far side of the moon landing

Evolving Chinese Space Ecosystem To Foster Innovative Environment

IRON AND ICE
ESA astronaut Alexander Gerst returns to Earth for the second time

Year of many new beginnings for Indian space sector

Scaled back OneWeb constellation Not to affect number of Soyuz boosters

Spacecraft Repo Operations

IRON AND ICE
Finding ways to protect crews from the effects of space radiation

NASA industry team creates and demonstrates first quantum sensor for satellite gravimetry

Raytheon awarded $114M for AN/SPY-6V radar integration, production

Celestia wins major ESA contract for UK

IRON AND ICE
Narrowing the universe in the search for life

A young star caught forming like a planet

Planets with Oxygen Don't Necessarily Have Life

Where did the hot Neptunes go

IRON AND ICE
NASA spacecraft hurtles toward historic New Year's flyby

Teledyne e2v has provided New Horizons with two specialist image sensors

New Horizons Notebook: On Ultima's Doorstep

Ultima Thule's First Mystery: Lack of a 'Light Curve'









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.