Featured Research

from universities, journals, and other organizations

25 Years Later, Voyager Mission Keeps Pushing The Space Envelope

Date:
August 19, 2002
Source:
NASA/Jet Propulsion Laboratory
Summary:
A quarter-century after NASA's twin Voyager spacecraft departed Earth to visit outer planets, the historic mission is flying a race against time.

A quarter-century after NASA's twin Voyager spacecraft departed Earth to visit outer planets, the historic mission is flying a race against time.

During the first 12 years after launch in 1977, the Voyagers chalked up a wealth of discoveries about four planets and 48 moons, including fast winds on Neptune, kinks in Saturn's rings and volcanoes on Jupiter's moon Io. As scientists and engineers mark the mission's silver anniversary, they hope at least one Voyager will pass beyond the boundary of the Sun's influence before the onboard nuclear power supply wanes too low to tell us what's out there. Voyager 1 is now the most distant human-made object, about 85 times as far from the Sun as Earth is. Voyager 2 is now about 68 times the Sun-Earth distance.

"After 25 years, the spacecraft are still going strong," said Dr. Edward Stone, Voyager project scientist since 1972 and former director of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Back in 1977, we had no way to know they would last so long. We were initially just on a four-year journey to Jupiter and Saturn."

The Voyager team at JPL still receives information almost daily from the durable spacecraft traveling beyond all the planets. The Voyagers are examining the far reaches of the solar wind, a gusty flow of particles hurled outward by the Sun. The eventual goal is to become the first spacecraft to taste interstellar space. Voyager 1, which launched on Sept. 5, 1977, flew past Jupiter and Saturn, then angled northward out of the plane of the planets' orbits. After Voyager 2 launched on Aug. 20, 1977, and completed its tour of Jupiter and Saturn, NASA extended the spacecraft's adventure with flybys of Uranus in 1986 and Neptune in 1989.

"A radio signal traveling at the speed of light takes nearly 12 hours to travel between Voyager 1 and Earth. That raises operational concerns," said Ed Massey, Voyager's project manager at JPL. " If something went wrong on board, at least a full day would lapse before a signal revealing the problem could reach Earth and commands to fix it could be returned. It could be too late." So the project team tries to anticipate any emergencies and program the spacecraft's computers with advance instructions on how to react to them, he said.

Both spacecraft are studying the vast bubble the Sun inflates around itself by outward pressure of the solar wind. The bubble has a boundary, called the heliopause, where this outward pressure is counterbalanced by inward pressure of the interstellar wind in our neck of the galaxy. The interstellar wind outside that boundary is a flow of atoms and other particles blasted from explosions of dying stars. The location of the heliopause varies with the level of solar activity during the Sun's 22-year sunspot cycle and with changes in the interstellar wind, Stone said. Some scientists suggest that, on a much longer time scale, the interstellar wind may occasionally press the boundary far enough inward to sway Earth's climate.

Voyager 1 is rushing toward the heliopause at about 1.6 million kilometers (about one million miles) a day. Whether it gets there before about 2020, while it still has adequate electrical power, depends on how far away the heliopause is. Recent estimates are that, depending on that distance, it would take Voyager 1 between seven and 21 years to reach the heliopause.

Voyager 1 has already discovered that the outbound solar wind around it is slowing from effects of inbound interstellar particles leaking through the boundary. A much better prediction of the boundary's location will come when the spacecraft encounters the termination shock, the zone where the solar wind begins piling up against the heliopause. That encounter may come within the next three years, Stone estimates.

Whatever their future holds, Voyager 1 and Voyager 2 have already earned a prominent place in the history of exploration. Among their big surprises: Jupiter's moon Io has active volcanoes. Jupiter's atmosphere has dozens of huge storms. Saturn's rings have kinks and spoke-like features. The hazy atmosphere of Saturn's moon Titan extends far above the surface. Miranda, a small moon of Uranus, has a jumble of old and new surfacing. Neptune has the fastest winds of any planet. Neptune's moon Triton has active geysers.

Long after they fall silent, the Voyager twins will keep speeding away from our solar system, each carrying an "interstellar outreach program" of recorded sounds and images from Earth, Massey said.

Further information about Voyager's past discoveries, current interstellar mission and messages from Earth is available at http://voyager.jpl.nasa.gov. JPL, a division of the California Institute of Technology in Pasadena, manages Voyager for NASA's Office of Space Science, Washington, D.C.


Story Source:

The above story is based on materials provided by NASA/Jet Propulsion Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

NASA/Jet Propulsion Laboratory. "25 Years Later, Voyager Mission Keeps Pushing The Space Envelope." ScienceDaily. ScienceDaily, 19 August 2002. <www.sciencedaily.com/releases/2002/08/020819065638.htm>.
NASA/Jet Propulsion Laboratory. (2002, August 19). 25 Years Later, Voyager Mission Keeps Pushing The Space Envelope. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2002/08/020819065638.htm
NASA/Jet Propulsion Laboratory. "25 Years Later, Voyager Mission Keeps Pushing The Space Envelope." ScienceDaily. www.sciencedaily.com/releases/2002/08/020819065638.htm (accessed October 22, 2014).

Share This



More Space & Time News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Comet Siding Spring Grazes Mars' Atmosphere

Comet Siding Spring Grazes Mars' Atmosphere

Newsy (Oct. 19, 2014) A comet from the farthest reaches of the solar system passed extremely close to Mars this weekend, giving astronomers a rare opportunity to study it. Video provided by Newsy
Powered by NewsLook.com
Latin America Launches Communications Satellite

Latin America Launches Communications Satellite

AFP (Oct. 17, 2014) Argentina launches a home-built satellite, a first for Latin America. It will ride a French-made Ariane 5 rocket into orbit, and will provide cell phone, digital TV, Internet and data services to the lower half of South America. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
This Week @ NASA, October 17, 2014

This Week @ NASA, October 17, 2014

NASA (Oct. 17, 2014) Power spacewalk, MAVEN’s “First Light”, Hubble finds extremely distant galaxy and more... Video provided by NASA
Powered by NewsLook.com
Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Saturn's 'Death Star' Moon Might Have A Hidden Ocean

Newsy (Oct. 17, 2014) The smallest of Saturn's main moons, Mimas, wobbles as it orbits. Research reveals it might be due to a global ocean underneath its icy surface. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins