July 2016 - The Spacewriter's Ramblings

Studying a Comet Long Term

This four-image montage shows the spectacular region of activity at the 'neck' of 67P/C-G. This is the product of ices sublimating and gases escaping from inside the comet, carrying streams of dust out into space. ESA/Rosetta/NAVCAM — This four-image montage shows the spectacular region of activity at the ‘neck’ of 67P/C-G. This is the product of ices sublimating and gases escaping from inside the comet, carrying streams of dust out into space. ESA/*Rosetta*/NAVCAM

I’ve been a comet fan since my grad school days. That was when I got pointed at Comet Halley and told, “study these images, and let’s figure out what’s happening with the plasma tail”. So, I pored over images of the comet taken from 1985-1986. I made lots of measurements and worked on papers with my team members. Eventually, we figured out what was happening with the plasma tail (hint: it’s affected by the solar wind). It was a pretty exciting time in my life, standing at the “frontier” of comet science (at that time) and opening my mind to the idea that what happens in the solar wind can make intricate “designs” in the shape and behavior of a plasma tail.

During that whole time, I was also intrigued by what a comet REALLY looks like. We didn’t have any close-up pictures of a comet nucleus. Sure, we had the Fred Whipple model of a chunky block of dusty ice (or icy dust, if you prefer) to study. And, there WERE some Giotto spacecraft images of the Halley nucleus. But they had to suffice until we could get REAL close-ups. What was needed was a long-term study of a nucleus. That’s what the Rosetta mission has done at the nucleus of Comet 67P/Churyumov-Gerasimenko.

Rosetta Orbits a Piece of Solar System History

For the better part of two years, the Rosetta spacecraft has visited the comet. It studied the chemical composition, sent back images, and gave astronomers the longest “timelapse” look at a comet ever. Along with its Philae lander, which functioned for only a short time, Rosetta is a great achievement. It’s something the European Space Agency and scientists around the world can be very proud to have sent. They’ve orbited a major piece of solar system history. They opened a window into the distant past when comets formed from materials that existed before the Sun and planets did. Studying a comet is like opening a treasure box.

In a few weeks, the mission will send its final images and data, and on September 30, 2016, the orbiter will do a slow crash landing on the surface of the comet. Its last messages should contain some very high-resolution images and data. You can follow the Rosetta mission at the ESA Website for the mission and track the spacecraft’s final days and weeks.

Rosetta: the Executive Summary

It’s been an amazing couple of years. Sure, we see what the comet’s surface looks like with its icy plains, boulders, and rocky inclusions. However, Rosetta’s chemical analysis on the comet’s ices and dust reveal information about the comet’s origins in the early epochs of the solar system’s formation. It also shows that the comet contains ingredients crucial to the formation of life. Mind you, Rosetta didn’t find life. However, uncovering the ingredients of life tells an important story. What did it find? Rosetta detected the amino acid glycine as well as the element phosphorus in the comet’s ices. These are key elements in our DNA and cell structures.

Comets as a Source of Water?

Another question astronomers wanted to answer was “Did Earth’s water come from comets?” Rosetta showed that the comet’s water chemistry is slightly different from Earth’s water. That means that ocean water on our planet didn’t all come from comets like 67P. Understanding where Earth’s water came from is still a big question in planetary science, and now astronomers are looking at other comets and asteroids for keys to the mystery.

I’m looking forward to the last images and data from Rosetta. I’m sure many comet fans, scientists, and graduate students are, too. There’s enough work in the treasury of information the spacecraft sent back to keep whole teams busy for years. In the end, even though Rosetta will no longer be working, its work WILL live on. That’s a major legacy for any mission!

Exploring Pluto

This image shows our previous best view of Pluto, provided by the Hubble Space Telescope, as it morphs into the spectacular new image from the New Horizons mission. The Hubble image was released in 2010, and the New Horizons image of the same region was taken on July 13, 2015 as the spacecraft -- nearing the culmination of its decade-long journey -- successfully captured the first detailed images of the distant dwarf planet. Credits: NASA/ESA/M. Buie (SwRI)/STScI/JHU-APL/SwRI

This image shows our previous best view of Pluto, provided by the Hubble Space Telescope, as it morphs into an image from New Horizons. The Hubble image was released in 2010, and the New Horizons image of the same region was taken on July 13, 2015, as the spacecraft successfully captured the first detailed images of the dwarf planet.
Credits: NASA/ESA/M. Buie (SwRI)/STScI/JHU-APL/SwRI

For my money, the New Horizons mission to Pluto and beyond is one of the most audacious and exciting missions sent out through the solar system. I say that as someone who cut her teeth doing science reporting on the Voyager missions! This time last year, we all waited for the spacecraft to arrive at the planet. When it did, on July 14, 2016, it whizzed past at a speed of 49,600 kilometers per hour, and then continued on its way. Hundreds of us — team members, friends, family, and the press were absolutely exhilarated at the dazzling visions of the distant world we were seeing. The data have been streaming back ever since then and each download provides an amazing look at a world that nobody expected. Here’s a “highlights” tour of what we know about Pluto so far.

Revealing Pluto

When the Pluto research papers came out in late 2015 and spring 2016, they revealed a curious and interesting place. Pluto is a real world, with diverse surface features and active geology. It has really fascinating surface chemistry. There’s a complex layered atmosphere, a somewhat puzzling interaction with the Sun, and a collection of small moons that are fascinating places in their own right.

Mind you, those facts (and the science behind them) are what the Pluto science team know after only a few months of data returned by the spacecraft. The full data load won’t finish relaying back to Earth until late 2016. So, there’s still lots to see — and learn. In the meantime, the mission team racks up awards and recognition by the scientific community for their contributions to planetary science. All of it is well-deserved.

Where’s New Horizons Now?

Right now, New Horizons is outbound from Pluto. It already has another target in sight — a Kuiper Belt object called 2014 MU69. NASA gave the official go-ahead for the extended mission to the next world “out there”. That flyby happens on January 1, 2019. I hope that we’ll all gather again to cheer the spacecraft on as it makes the first-ever close encounter with a KBO beyond Pluto. It’s been an amazing ride, and it’s all thanks to the amazing spacecraft and its Earthbound support team.

The Spacewriter's Ramblings

Monthly Archives: July 2016

The Rosetta Mission at Comet 67P Will Soon End