ISEE-3: An Old Friend Comes to Visit Earth

Artist's concept image of ISEE-3 (ICE) spacecraft. Image Credit: NASA

It launched in 1978. It was the first satellite to study the constant flow of solar wind streaming toward Earth from a stable orbit point between our planet and the sun known as the Lagrangian 1, or L1. Monitoring that wind helped scientists better understand the interconnected sun-Earth system, which at its most turbulent can affect satellites around Earth.

In 1984, it was given a new mission and called the International Cometary Explorer. In September 1985, it passed directly through the tail of Comet Giacobini-Zinner, making it the first spacecraft to encounter and gather data from a comet. It also went on to fly by Comet Halley in March 1986. From 1991 until 1997, when it was too far away for reliable communications, this satellite continued to investigate the sun. Now it’s coming home to visit – making its closest approach to Earth in August 2014 before it heads back out to interplanetary space.


Top-down view of the orbit of ISEE-3 (ICE) relative to the inner solar system. We see the orbit alternates with the spacecraft occasionally closer, then further from the Sun than Earth.
Image Credit: NASA’s Scientific Visualization Studio

This is the story of NASA’s and the European Space Agency’s International Sun-Earth Explorer (ISEE-3). Beacon signals from the spacecraft’s communications system demonstrate that it is still operating, but scientists and engineers don’t know how well. This beacon is also how they know the spacecraft is still following the same orbit around the sun, moving slightly faster than Earth.

The ISEE-3 mission was state-of-the-art when it launched. It used an S-band frequency, part of the microwave band of electromagnetic waves, for communication. At the time, this frequency was reserved for government air and space communications. Today, the S-band once used for ISEE-3 is outmoded. Solar wind data that ISEE-3 gathered at the rate of once every 40 minutes has been replaced by spacecraft with instruments that are 10,000 times faster.

ISEE-3 opened new pathways for scientific exploration. Although overtaken by advances in technology, ISEE-3 remains a testament to the scientists and engineers who conceived, launched and managed this versatile, old spacecraft.


An oblique view of the orbit of ISEE-3 (ICE) relative to the inner planets. Close-up view of the Earth flyby in mid-2014.
Image Credit: NASA’s Scientific Visualization Studio

Today, some citizen scientists are investigating whether it would be feasible to communicate with ISEE-3 for the first time in almost two decades in order to send commands to return it to L1. A daunting prospect after all this time with NASA’s old friend.

 

The April 15, 2014 Total Lunar Eclipse by Astronomer Michelle Thaller

Tonight’s the night folks, so step outside and view an amazing sight.

The public will have the opportunity to view and learn more about the April 15, 2014 total lunar eclipse on NASA Television, the agency’s website and social media.

The eclipse begins about 2 a.m. EDT and will last about three hours. The eclipse’s peak, when the moon will enter Earth’s full shadow, or umbra, will occur at 3:45 a.m. EDT – Learn more here: www.nasa.gov/LRO

SpaceX Prep Continues for a Monday Launch.

SpaceX Falcon Rocket. Photo Credit: SpaceX

International Space Station Program officials and representatives of SpaceX decided Saturday to continue preparations for the launch of the Falcon 9 rocket and the Dragon cargo craft to the space station Monday from Launch Complex 40 at the Cape Canaveral Air Force Station, Fla., despite the failure Friday of a backup computer component that provides redundancy for commanding the Mobile Transporter rail car on the truss of the station. A final decision on whether to launch Dragon Monday will not be made until another status meeting is conducted Sunday morning.

LATEST UPDATE:  SpaceX launch has been scrubbed for today.

Live streaming video by Ustream

The briefing will provide an update on the status of the SpaceX-3 cargo mission launch to the International Space Station, currently scheduled for 4:58 p.m. Monday, April 14, and on the failure on Friday of a backup computer component that provides redundancy for commanding the Mobile Transporter rail car on the truss of the station.

The component, called a multiplexer demultiplexer (MDM) is one of more than a dozen housed on the truss of the station that routes computer commands to various systems on the outpost. The failure Friday to a box called EXT-2, a backup box to a prime component in the S0 truss that measures 10.5 x 14.9 x 16.4 inches and weighs 50.8 pounds, occurred during a routine health check of the device. The prime multiplexer continues to operate flawlessly, and there has been no impact to station operations. The crew was informed of the problem and is in no danger, continuing its normal complement of research work and routine maintenance. A reboost of the station using the ISS Progress 53 thrusters was conducted Saturday as planned and placed the laboratory at the correct altitude for Soyuz crew landing and launch operations in May.

SpaceX Dragon Cargo ship docks with ISS. Photo Credit: SpaceX

Station program officials, flight controllers and teams of engineers are working to determine whether there is any risk to launching the SpaceX cargo craft Monday. They will evaluate whether the station has enough redundancy to permit the launch to proceed, which would result in Dragon arriving at the station Wednesday where it will be grappled and berthed to the Earth-facing port of the Harmony module by Expedition Commander Koichi Wakata of the Japan Aerospace Exploration Agency and NASA Flight Engineer Rick Mastracchio. The station’s Canadarm2 robotic arm that would be used to capture and berth Dragon has other redundancy capabilities not affected by the backup MDM failure.

While a final decision on the SpaceX launch is being reviewed, another team of engineers is laying out a timeline for a contingency spacewalk that is required to replace the failed spare MDM. No date for the spacewalk has been scheduled. Such a spacewalk is one of the so-called “Big 12” spacewalks that station crews train to execute for the loss of a critical component on the complex.

For now, Dragon remains scheduled for launch Monday at 4:58 p.m. EDT

 

NASA to Provide Live Coverage and Commentary of April 15 Lunar Eclipse

This photo was taken by Doug Murray of Palm Beach Gardens, Florida, during the total lunar eclipse of Oct. 27, 2004. NASA Science News.

The public will have the opportunity to view and learn more about the Tuesday, April 15 total lunar eclipse on NASA television, the agency’s website, and social media. Coverage begins at 2 a.m. EDT and will last about three hours. The eclipse’s peak, when the moon will enter the Earth’s full shadow or umbra, will occur at 3:45 a.m.

Credit: Sky and Telescope.com

The United States will be in a prime orbital position and time of day to view the eclipse. Depending on local weather conditions, the public will get a spectacular view looking into the sky as the moon’s appearance will change from bright orange to blood red to dark brown and perhaps gray. The eclipse is a phenomenon that occurs when the Earth, moon and sun are in perfect alignment, blanketing the moon in the Earth’s shadow.  The United States will not be able to witness a full lunar eclipse in its entirety again until 2019.

Leading up to the eclipse, NASA will host a Reddit Ask Me Anything (AMA) on Monday, April 14 at 2 p.m. with astronomers from the agency’s Marshall Space Flight Center. Various NASA researchers also will be available for media interviews. NASA Twitter, Google+, Facebook, and Instagram followers will be able to join the conversation and ask questions using the hashtag #eclipse.

The public will be able to tag and share their images of the eclipsed moon on Instagram and on the agency’s Flickr group at:

https://www.flickr.com/groups/nasalunareclipse

Live NASA TV coverage and commentary will begin at 1 a.m. To view the coverage and access eclipse streaming video, visit:

http://www.nasa.gov/nasatv

 

Dwayne Brown
Headquarters, Washington
202-358-1726
dwayne.c.brown@nasa.gov

Janet Anderson
Marshall Space Flight Center, Huntsville, Ala.
256-544-0034
janet.l.anderson@nasa.gov

Nancy Neal Jones
Goddard Space Flight Center, Greenbelt, Md.
301-286-0039
nancy.n.jones@nasa.gov

Supernova . . . The Galactic Sweeper.

Image credit: X-ray: NASA/CXC/Morehead State Univ/T.Pannuti et al.; Optical: DSS; Infrared: NASA/JPL-Caltech; Radio: NRAO/VLA/Argentinian Institute of Radioastronomy/G.Dubner

Supernovas are the spectacular ends to the lives of many massive stars.  These explosions, which occur on average twice a century in the Milky Way, can produce enormous amounts of energy and be as bright as an entire galaxy. These events are also important because the remains of the shattered star are hurled into space.  As this debris field – called a supernova remnant – expands, it carries the material it encounters along with it.

Astronomers have identified a supernova remnant that has several unusual properties. First, they found that this supernova remnant – known as G352.7-0.1 (or, G352 for short) – has swept up a remarkable amount of material, equivalent to about 45 times the mass of the Sun.

Chandra Space Telescope. Credit: NASA

Another atypical trait of G352 is that it has a very different shape in radio data compared to that in X-rays. Most of the radio emission is shaped like an ellipse, contrasting with the X-ray emission that fills in the center of the radio ellipse.  This is seen in a new composite image of G352 that contains X-rays from NASA’s Chandra X-

Very Large Array. Credit: NSF/NASA

ray Observatory in blue and radio data from the National Science Foundation’s Karl G. Jansky Very Large Array in pink.  These data have also been combined with infrared data from the Spitzer Space Telescope in orange, and optical data from the Digitized Sky Survey in white. (The infrared emission to the upper left and lower right are not directly related to the supernova

The Spitzer Space Telescope. Credit: NASA Jpl/Caltech

remnant.)

A recent study suggests that, surprisingly, the X-ray emission in G352 is dominated by the hotter (about 30 million degrees Celsius) debris from the explosion, rather than cooler (about 2 million degrees) emission from surrounding material that has been swept up by the expanding shock wave. This is curious because astronomers estimate that G352 exploded about 2,200

Sloan Digitized Sky Survey Telescope. Credit: SDSS

years ago, and supernova remnants of this age usually produce X-rays that are dominated by swept-up material.  Scientists are still trying to come up with an explanation for this behavior.

Although it does not produce a lot of X-ray emission, the amount of material – the aforementioned 45 times the Sun’s mass – swept up by G352 is remarkably high for a supernova remnant located in our Galaxy. This may indicate that a special type of evolution has occurred, in which the massive star that exploded to create G352 interacted with an extraordinary amount of dense surrounding material.

Astronomers also conducted a search for a neutron star that may have been produced by the supernova explosion. They did not find any hints of a neutron star in G352, another astronomical puzzle involved with this system. One possibility is simply that the neutron star is too faint to be detected or that the supernova created a black hole instead.

G352 is found about 24,000 light years from Earth in the Milky Way galaxy. A paper describing these enigmatic results was published in the February 20th, 2014 issue of The Astrophysical Journal, and is available online.  The first author of this paper is Thomas Pannuti from Morehead State University in Morehead, Kentucky, with co-authors Oleg Kargaltsev (George Washington University), Jared Napier (Morehead State), and Derek Brehm (George Washington).

Nasa’s Twin Study to Launch Next Year.

Next year, with the assistance of the world’s only twin astronauts, NASA will conduct an unprecedented experiment in human biology.

While one twin remains on the ground, the other will circle Earth onboard the International Space Station for a full year.

Will the twins still be identical when they are re-united?

The answer could help NASA make space travel safer for generations of astronauts to come.