News from Space: New Horizons Passes Neptune

new-horizons-neptuneIt certainly has been a momentous few weeks for space exploration! Between the final weeks of August and the month of September, we’ve seen the Curiosity rover reach Mount Sharp, the Rosetta spacecraft created the first full map of a comet’s, the completion of the Orion space module, and the MAVEN orbiter reach Martian orbit. And before the month is out, India’s Mars Orbiter Mission (MOM) will also arrive in orbit around the Red Planet.

Despite all these developments, that occurred (relatively) close to home, there was even more news to be had, coming all the way from the edge of the Solar System no less. At the tail end of August, NASA announced that the New Horizons space probe passed Neptune orbit and is on its way to Pluto. Launched back in 2006 for the purpose of studying the dwarf planet, the probe is expected to arrive on July 14th of next year.

new-horizons-neptune-8NASA says that the the craft passed the Neptunian orbit at 10:04 pm EDT on Monday August 25th, which coincided with the 25th anniversary of Voyager 2’s flyby of Neptune in 1989. But where Voyager came within 4,950 km (3,080 mi) of the gas giant, the New Horizons craft passed by at a distance of 3.96 billion km (2.45 billion mi). The spacecraft is now almost 4.42 billion km (2.75 billion mi) from Earth, and is the fastest man-made object ever sent into space.

Nevertheless, New Horizons’ Long Range Reconnaissance Imager (LORRI) was still able to capture images of Neptune and its giant moon Triton. As you can see from the image below, Neptune appears as the large white disc in the middle, while Triton is the small black dot passing in front and sitting slightly to the ride. NASA says that Triton may be very similar to Pluto and the information gathered by Voyager 2 may prove helpful in the coming encounter.

new_horizons_plutoRalph McNutt of the Johns Hopkins University Applied Physics Laboratory.

There is a lot of speculation over whether Pluto will look like Triton, and how well they’ll match up. That’s the great thing about first-time encounters like this – we don’t know exactly what we’ll see, but we know from decades of experience in first-time exploration of new planets that we will be very surprised.

The first mission in NASA’s New Frontiers program, the New Horizons mission was launched on January 19, 2006 atop an Atlas V rocket from Cape Canaveral, Florida. It broke the record for the fastest man-made object on lift off with a speed of 58,536 km/h (36,373 mph). The 478 kg (1,054 lb) spacecraft was sent on a 9.5-year mission to fly by Pluto – a distance so far that radio signals from the nuclear-powered probe take four hours to reach Earth.

new-horizons-neptune-7Sent on a slingshot trajectory using the gravitational pull of Jupiter, which tacked on another 14,480 km/h (9,000 mph) to its speed, New Horizons will pass Pluto in July of next year at a distance of 13,000 km (8,000 mi). After this encounter, it will continue on out of the Solar System, during which it will be in the distant Kuiper belt studying one or more Kuiper belt objects (KBOs).

Though this will still not rival Voyager 1’s accomplishments, which left our Solar System last year, New Horizons promises to gather far more information on the Outer Solar System and what lies beyond. All of this will come in mighty handy when at last, humanity contemplates sending manned missions into deep space, either to Alpha Centauri or neighboring exoplanets.

Sources: gizmag.com, nasa.gov

News From Space: 200 km Water Jets on Europa

europa-landerAs the prime candidate for extra-terrestrial life, the Jovian moon of Europa has been the subject of much speculation and interest over years. And while our understanding of the surface has improved – thanks to observations made by several space probes and the Hubble space telescope – what lies beneath remains a mystery. Luckily, Europa may yet provide Earth scientists with a chance to look at its interior.

Earlier this month, data collected from the Hubble space telescope suggested that enormous jets of water more than 200 kilometers tall may be spurting intermittently from the moon’s surface. The findings, presented last week to the American Geophysical Union, await independent confirmation. But if the jets are real, the frozen world would join the tiny number of others known to have active jets, including Saturn’s moon Enceladus and Neptune’s moon Triton.

europa-lander-2What’s more, should these newly observed water plumes be tapping into some Europan sea, they could be bringing material to the surface that would otherwise stay hidden. Follow-up observations from Earth or with probes around Europa could sample the fountains, hunting for organic material and perhaps finding the evidence need to prove that living organisms exist beyond Earth.

Scientists spotted the plumes thanks to ultraviolet images taken by Hubble in December 2012. The research team, which hails from the Southwest Research Institute in Texas, then published their research in Science magazine. In the paper, astronomer and co-author Lorenz Roth explained their findings:

We found that there’s one blob of emission at Europa’s south pole. It was always there over the 7 hours we observed and always at the same location.

Previous observations from NASA’s Galileo mission, which visited the Jupiter system in the 1990s and early 2000s, suggest that Europa’s south pole is full of ridges and cracks quite similar to features called tiger stripes on Enceladus that spew water.

europa_chaosterrainLorenz and his team looked back through previous Hubble data to see if the plumes could have been spotted earlier but saw nothing, suggesting that they are likely transient. At the time, Europa was at its farthest from Jupiter, which could explain why the jets appeared only then. Researchers recently determined that Enceladus’ plumes are weakest when the moon is closest to Saturn, likely because the ringed planet’s gravity squeezes the tiger stripes shut.

Astronomer Kurt Retherford, also of SwRI and another co-author, claimed that the case of Enceladus helped them to make a connection with what they were observing:

We actually saw this press release on Enceladus. And we thought, ‘Oh my god! This is the explanation’” for why Europa’s plumes might only appear when it’s far from Jupiter.

In the past, scientists have looked for evidence of jets coming from Europa’s surface. When the Voyager probes flew by in the 70s, one image showed a fuzzy spot that some thought to be a plume, though most considered it an artifact of imaging. Galileo also saw a row of dark spots on a ridge of Europa which looked similar to spots seen on planet Earth before an eruption begins.

europaBecause of these previous false positives though, scientists are likely to be cautious when interpreting these newest results. But even with these reservations, Robert Pappalardo – who leads the planning team for the Europa Clipper Pre-Project (a proposed mission to Europa) – said that he’s already discussing with other scientists how these new results should affect their study priorities.

For instance, some future orbiter headed to Europa could carry detectors specifically designed to search for heavy organic molecules that could be indicative of life in the subsurface. When it passed over the geyser’s spray, it would be bathed in material from the moon’s interior, giving scientists a window into Europa’s ocean. Pappalardo also hopes that the finding will help push Europa to a place of high priority in NASA’s exploration agenda.

Due to budget constraints, a manned mission is not yet feasible, but NASA has indicated that it would be willing to send a robot lander there in the near future. In addition, recent computer models provided from the University of Texas showed that the ice is likely to be thinnest at the equator. Between the possibility that the oceans might be most accessible in this region, and the likelihood that some of that water escapes into space, unlocking the mysteries of the Jovian satellite might be easier than previously thought.

europa_gieserSources: wired.com, science.jpl.nasa.gov