All posts by Kimberly Ennico Smith

Focus is the name of the game! Flight Day (Nov 17, 2013): Part 2 Experiencing Microgravity for the First Time!

Reposted from https://blogs.nasa.gov/mission-ames/2013/12/17/focus-is-the-name-of-the-game-flight-day-nov-17-2013-part-2-experiencing-microgravity-for-the-first-time/.

My final blog summarizes my experiences of the flight and my evolving perspective on this type of platform for doing engineering, science and technology experiments. (Earlier posts, part 1 here, part 2 here).

First Impressions. So for a first timer, the first question asked is, “So what was it like?” I am so glad I had an audio recorder since my first experience on the onset of micro-gravity for the first time (and hopefully not the last time) in my life was said in deadpan fashion (totally not typical for me) “Alright. That’s interesting. Oh, wow. Okay. Yeah. We’re good.”

(The second question is “Did you get sick?” Well, it was challenging to keep disciplined to keep my head straight, especially during the 1.8-2G periods. I did not get sick, but got close to being sick on Parabola #25. But it was totally my fault since I looked out the window between Parabola #24 & #25 and saw the horizon almost vertical and that messed with my head. Lesson learned: don’t look out the window.)

In the interest of full disclosure, one payload had been having some intermittent issues that, like all intermittent issues, reared its head during a pre-flight end-to-end test a day before the flight. Luckily I had a contingency operations sketched out which performed perfectly. So when were on the plane and were doing the set-up and startup, I was really “uber-focussed” on the payload and not on myself for the first few cycles. When things started to get into a rhythm around Parabola #5 I had no idea we were 1/5th of the way done. Wow.

between_parabola1_and_2

“That was short. That was very short.” My comments after the very first parabola, which was a Martian (0.33 G) scenario. This image shows our team’s positions in between parabola 1 & 2. We did not have space enough to fully lay down so we reclined against the side of the aircraft. Left to right is Con Tsang, myself (monitoring a payload via a table), Cathy Olkin, and Alan Stern (face not visible). The photo is taken via Go-Pro camera on the head of Dan Durda who was across the way. Eric Schindhelm, who rounded out our team, was next to Dan and not in this view.

The rapid change between the onset of low-gravity for about 10-15 seconds followed by 2-3 sec transition to what appeared to be about 30s of 1.8-2G forces was very unexpected. With each parabola I did start to realize that the set-up time for the manual operation of one payload took way too long. (Lesson learned)

Sometimes we had unexpected escapes (I escaped my foot-holds on Parabola #7) and Eric Schindhelm (shown below) escaped the next one.

eric_parabola8

Con was monitoring BORE and deftly diverted Eric’s collision path. For BORE, the key thing was to keep the box free from any jostling by others or the cables.

The payloads. We had two payloads, each with different goals for the flight. The fact that a decision to tether them together (made a few weeks before the flight) complicated the conops (concept of operations). One was a true science experiment: BORE, the Box of Rocks Experiment. The other was primarily an operations test for the SWUIS, the Southwest Universal Imaging System. Both experiments are pathfinder experiments for the emerging class of reusable commercial suborbital vehicles. Providers like Virgin Galactic, X-COR, Masten Space Systems, Up Aerospace, Whittinghill Aerospace, etc. You can read more about this fleet of exciting platform at NASA’s Flight Opportunity page https://flightopportunities.nasa.gov/, where they have links to all the providers.

swuis_bore_setup_1

From left to right: Dan & Con monitoring BORE (aluminum box with foamed edges) while Cathy holds onto the SWUIS camera doing a “human factors” test using a glove (yellow). Image from Go-Pro camera affixed to the SWUIS control box.

swuis_pib_target_2

View of the SWUIS control box and Go-pro camera (used for situation awareness) while Dan’s holding it. You can see the SWUIS target that we used for the operations testing.  Image from a Go-Pro camera affixed to Dan’s head. Multiple cameras for context recording were definitely a must! (Lesson Learned)

dan_swuis_parabola23

Dan Durda taking a test run with SWUIS on Parabola #23 (19th zero-G).

With BORE, we ask the question: how do macro-sized particles interact in zero gravity? When you remove “gravity” from the equation, other forces (like electro-static, Van der Waals, capillary, etc.) dominate. In a nut shell, BORE is a simple experiment to examine the settling effects of regolith, the layer of loose, heterogeneous material covering rock, on small asteroids.

Our goal is to measure the effective coefficient of restitution (http://en.wikipedia.org/wiki/Coefficient_of_restitution) in inter-particle collisions while in zero-g conditions. The experiment consists of a box of rocks. There are two boxes, one filled with rocks of known size and density, one filled with random rocks. Video imagery (30fps) is taken of the contents of each box during the flight. After the flight, the plan is to use different software (ImageJ, Photoshop, and SynthEyes) to analyze the rocks and track their movements from frame to frame. The cost of BORE is less than $1K in total, making it in reach of a the proceeds of a High School bake sale!

BORE does need more than 20 s of microgravity to enable a better assessment of rock movement, and this is exactly why this experiment is planned for a suborbital flight where 4-5 minutes of microgravity conditions can be achieved. Here, we used the parabolic flight campaign to test the instrumentation and get a glimpse of the first few seconds of the rock behavior. With this series of 15-20s of microgravity, we made leaps forward from previous tests using drop towers which provide only 1-2s of microgravity.

Today’s Microgravity platforms and durations of zero-G fromhttp://www.nasa.gov/audience/foreducators/microgravity/home/.

  • Drop Towers (1-5 s)
  • Reduced-Gravity Aircraft (10-20s)
  • Sounding Rockets (several minutes)
  • Orbiting Laboratories such as the International Space Station (days)

bore_samplezg_images

Some BORE images from one of the zero-G parabolas. Top Row: (left) Rest position of and (right) free-floating bricks of known size (they are actually bathroom tiles from Home Depot) but have the ratio L:W:H of 1.0:0.7:0.5. Surprisingly this is near the size and ratio of fragments created from laboratory impact experiments (e.g. Capaccioni, F. et al. 1984 & 1986, Fujikawa, A. et al. 1978) and similar to the ratio of shapes of boulders discovered on the rubble-pile asteroid Itokawa (see below).

Why is this important? Well, if you want to visit an asteroid someday and are designing tools to latch onto it, drill/dig into it, collect samples, etc. the behavior of collisional particles in this micro/zero-gravity environment is important. Scientifically, if you want to understand more about the formation, history and evolution of an asteroid where collisional events are significant, knowing more about how bombardment and repeated fragmentation events work is a key aspect.

itokawa_iss_forscale

Source: NASA & JAXA. The first unambiguously identified rubble pile. Asteroid 25143 Itokawa observed by JAXA’S Hayabusa spacecraft. (Fujiwara, A. et al. 2006). The BORE experiment explored some of the settling processes that would have played a role in this object’s formation.

SWUIS was more of a “operations experiment.” This camera system has been flown on aircraft  before to hunt down elusive observations that require observing from a specific location on earth. For example, to observe an occultation event, when a object (asteroid, planet, moon) in our solar system crosses in front of a distant star, the projected “path” of the occultation on our planet is derived from the geometry and time of the observation, similar to how the more familiar solar and lunar eclipses only are visible from certain parts of the Earth at certain times. Having a high-performance astronomical camera system on a flying platform that can go to where you need to observe is powerful. So, SWUIS got its start in the 1990s when it was used on a series of aircraft. You can read more about those earlier campaigns at http://www.boulder.swri.edu/swuis/swuis.instr.html.

Over the past few years I have been helping a team at the Southwest Research Institute update this instrument for use on suborbital vehicles that get higher above the earth’s atmosphere compared to conventional aircraft. Suborbital vehicles can get to 100 km (328,000 ft.; 62 miles) altitude, whereas aircraft fly mainly at 9-12 km (30,000-40,000 ft.; 5.6-7.5 miles). Flying higher provides a unique observational space, both spectrally (great for infrared and UV as you are above all of the water and ozone, respectively), temporarily (you can look along the earth’s limb longer before an object “sets” below the horizon) and from a new vantage point (you can look down on particle debris streams created by meteors or observe sprites & elves phenomena in the mesosphere). 100km altitude is still pretty low compared to where orbiting spacecraft live, which is 160-2000 km (99-1200 miles) up (LEO/Low Earth Orbit). For example, our orbiting laboratory, the International Space Station is 400 km (250 miles) in altitude.

suborbital_flight_trajectory

The SWUIS system today consists of a camera and lens, connected by one cable to a interface box. The interface box, which is from the 1990s version, allows one to manually control gain and black-level adjustments via knobs. It also provides a viewfinder in the form of a compact LCD screen. Data is analog but then digitized to a frame-grabber housed in a laptop. The 1990s version had a VCR to record the data, but since we are in the digital age, the battery-operated laptop augmentation was a natural and easy upgrade. The camera electronics are powered by a battery which makes it portable and compact. For this microgravity flight I introduced the notion of a tablet to control the laptop, to allow for the laptop to be stowed away. In practice this worked better than expected and my main take away is that the tablet is best fixed to something rather than hand-held to prevent unwanted “app-closure.” However, having a remote terminal for the laptop also would work.

Here’s a series of three short videos (no sound) of three legs when I got to hold the Xybion camera on Parabolas #13, 14 & 15. This captures how terribly short all the parabolas are and if you are doing an operations experiment, how utterly important it is to be positioned correctly at the start. One test was to position myself and get control of the camera and focus on a test target. A second test was to practice aiming at one target and then reposition for another target within the same parabola.

SWUIS_ZeroG_Parabola13_Web2

SWUIS_ZeroG_Parabola14_Web2

SWUIS_ZeroG_Parabola15_Web2

Above, the links are for lo-res (to fit within the upload file size restrictions on this site), no sound Videos of Parabola #13,14,15  (7,8 &9th in microgravity). By the third time I was getting faster at set-up and on-target time.

In 1-G this camera and lens weigh 6.5 lbs. (3 kg) . Held at arms length, when I was composing the test in my lab, as I scripted the steps, I had trouble controlling the camera. In fact, I was shaking to keep camera on target after some seconds. I was amazed at how easy it was to hold this in zero-G, and complete the task. The Zero-G flight told us many things we need to redesign. One issue we learned was the tethering cabling was not a good idea and in some cases the camera, held by one person, was jerked from the control box, held by another person. In the next iteration, one of those items will need to be affixed to a structure to remove this weakness.

My lessons learned from the whole experience: Everything went by very quickly. Being tethered was difficult to maintain. Design the conops differently (what we did seemed awkward). Laptop and tablet worked better than expected. Hard to concentrate on something other than the task at hand. Don’t plan too much. Have multiple cameras viewing the experiment. Need to inspect the cable motion via video, as it was hard to view it in-situ. Very loud, hard to heard, hard to know what other people were working on. The video playback caught a lot more whoops during transitions to zero-G than I remembered. Heard the feet-down call clearly but not the onset of zero-G. The timing between parabolas is very short. The level breaks were good to reassemble the cabling then. Next time, don’t hang onto the steady-wire which is attached to the plane (I got that idea from Cathy & Alan next to me) as it caused more motion than needed (the plane kept moving into me): instead remain fixed with the footholds and do crouch positions like Con & Dan did and let the body relax (Con & Dan were most elegant).

And, my biggest take-away of all: If you want to do a microgravity experiment, I strongly recommend doing a “reconnaissance” flight first. Request to tag along a research flight to observe, perhaps lend a hand as some research teams might need another person. Observe the timing and cadence and space limitations. Use that to best perform your experiment. It is an amazing platform for research and engineering development and can truly explore unique physics and provide a place to explore your gizmo’s behavior in zero-G and find ways to make it robust before taking it to the launch pad.

I am very much hoping to experience microgravity again! With these same two payloads or with others. One of the key points of these reduced-gravity flights, they fly multiple times a year, so in theory, experiment turn-around is short. Ideally I wished we flew the next day. I could have implemented many changes in the payload-operations and also in Kimberly-operations.

Our team is now working to assess what worked and what did not work on this flight. We achieved our baseline goals, so that is great! Personally, I wished I had not been that focused on certain aspects of the payload performance and made more time to look around. However, that said, my focus keyed me on the task at hand, the payload performed better than expected, and when you have 10-15s, focus is the name of the game!

It’s time to fly and go weightless! Microgravity Flight Day (Nov 17, 2013): Part 1, TSA Check, Board, Ascent, and Flight Profile.

Reposted from https://blogs.nasa.gov/mission-ames/2013/12/17/its-time-to-fly-and-go-weightless-microgravity-flight-day-nov-17-2013-part-1-tsa-check-board-ascent-and-flight-profile/.

This is a second entry (part one here, part three here) of a three part blog series about my recent experience in microgravity.

pre-flightphoto

The team is outfitted in their flight suits ready to go! left –to-right Kimberly Ennico (me), Con Tsang, Eric Schindhelm, Dan Durda, and Cathy Olkin. The photo was taken by Alan Stern, another member of the team, rounding us to six flyers. Con & Cathy had flown once before. Dan & Alan had multiple flight histories. It was Eric & I to savor the first-time-flyer award. All my colleagues work at the Southwest Research Institute in Boulder, Colorado.

In writing this blog entry, I still giggle at recalling the moments before the flight. We actually had a TSA check before boarding the plane. Now, pretty much every person has a go-pro or a recorder strapped to some limb, all carefully secured in the pockets of his/her flight suit. So as each person went through security, all the pockets had to be emptied before the TSA wand-scan, and then all the devices got re-pocketed ready for the adventure.

So what were in my pockets? I had some spare duct-tape affixed to plastic (for easy removal) to do patch-taping (came in super handy), a Nexus tablet for one of the experiments (with velcro on its backside ass it needed to be velcroed to the floor), 6 AA fresh batteries (for me to putt in one of the payloads during the setup leg), two checklists (both velcroed to me), and an audio recorder (affixed to my arm with a iPod armband). Any items that did not have some sort of way to be strapped or velcroed down had to be lanyard to you (such as a camera).

kim_boarding

That’s me outfitted with documentation. I’m “walking documentation.” My right shoulder holds an audio recording device, my right thigh our checklists, and my left wrist (not shown) the list of tests vs. parabola. If you look closely my name badge is upside down, indicating I am a first-flyer.  (Photo by Dan Durda).

I was assigned seat 3C for takeoff (and yes, they actually gave us boarding passes!). There are a few rows of seats in the back which all fliers have to be buckled in for take up.  We boarded from the rear of the 727-200. There was an in-flight safety briefing (oxygen, life jacket, seatbelts). There is an emergency card, tailored for Zero-G, similar to what was provided for SOFIA. The plane is operated by Zero-G corporation, but registered under Amerijet. Its call sign was AJT213. The main body is empty with padded floors, walls and ceilings. There are specific areas to bolt down footstraps and equipment. For those items that cannot be bolted down, there are a series of Velcro strips we placed the day before. This turned out to be important as during the in between microgravity parabolas, you experience 1.2-2 G and holding free-floating equipment will immediate come crashing down. So this experiment which involve 5 separate free-floating equipment, having a “safe place to store.”

At approximately 9:16 am EST (local time), we taxied and the takeoff felt just like a normal plane. At about 10 minutes after takeoff, we were instructed we could begin our set-up. This set-up leg is about 15-30 minutes in length. From our practice sessions last week we knew that setting up SWUIS took about 15 minutes (with no glitches). BORE took a similar amount and they are dovetailed in such a way that we need to go in parallel but also stage certain setup first. So the checklist came in handy to remind us our “dance” for setup. We put in fresh batteries for our equipment and got it up and running in a we bit more than 15 minutes, after experiencing a momentary pause when a known interference issue might have reared its head, but it played nice that morning.  We had a pretty complex set-up, which I realized we should simplify on future flights and I made some oral notes into the audio-recorder.

We knew from the review the day before we would be experiencing 25 parabolas in total, performed in bunches of five with a flat 1-2 minutes of 1 G of “level” in between. The first “set” would be four Martian (1/3 G) and one zero-G. The second set would be one lunar (1/6 G) and 4 zero-G. And all the remaining parabolas would be zero-G. There was only one experiment on board who had requested the Martian gravity, all others needed zero-G. I gathered that the tourist flights get 15 parabolas also similarly put in 5-sets, and depending on the experiments on the flight, the number of Martian & lunar parabolas are tailored appropriately.

Besides the research teams, Zero-G assigns at least one “coach” per experiment group. He or she can help with the experiment logistics, and also provide assistance if one of the team comes down with motion sickness. To avoid motion sickness, I was strongly advised not to turn my head, or if I had to turn my head, to ensure I turned my entire upper torso and slowly, and this especially important during the high-G parts of the parabolas.

Let me divert from the experience to summarize what the plane is supposed to do to provide these “periods” of reduced gravity. This “reduced-gravity environment” is created as the plane flies on a parabolic path: the plane climbs rapidly at a 45 degree angle (“pull up”), traces a parabola (“pushover”), and then descends at a 45 degree angle (“pull out”). During the pull up and pull out segments, everything on board, then crew and experiments, experience accelerations of about 2 g (and boy did I feel this! This was actually more striking than the <1 g). During the parabola (pushover), net accelerations are supposed to drop as low as 1.5×10-2 g for about 15-20 seconds. For me, this was the largest take-away of the entire experience: those periods of zero-G went by very, very, very quickly. Also the period of 2G felt like they went by much slower, but essentially they were the of similar duration. I was very surprised, but when I decoded my voice recorder results and looked at the camera data taken by our two experiments (which were time stamps) those “pushover” events were indeed in “20 s duration time chunks.”

After  5 parabolas, the aircraft was leveled off to get us back to “old familiar” 1 G. This was a key time I learned to help re-position cables (and in many cases, people!) to get ready for the next series of five. We erred in our conops design to rotate things in threes, which did not work very well with the break after 5 parabolas. Having known now the importance of using those breaks, I would have designed the operations-experiment differently. The other science experiment was not affected by that issue.

After speaking with other folks, apparently, the “20s duration of zero-G” is driven by safety limits on the aircraft’s flight profile, to drop only a few thousand feet during the parabolas. Here’s where the suborbital rockets (one-use) and the emerging new reusable commercial suborbital platforms come in, as they promise 4-5 minutes of microgravity in a single flight. This longer duration of zero-G is highly attractive for some experiments. However, others may still want multiple zero-G test times in a short time and those are nicely provided by these aircraft doing parabolic flight profiles.

Our entire flight from nose-up to nose-down was only 2 hrs. The time between the start of parabola 1 and the end of parabola 25 was about 1 hr. It was quick.

After the flight I looked up the flight path on flightaware.com and we were doing some pretty neat aerobatics over the Gulf of Mexico. Our altitude ranged from 25,000 ft. to 20,000 ft. during the parabolic maneuvers.

flightaware_1

flightaware_2

 

My final blog summarizes my experiences of the flight and my evolving perspective on this type of platform for doing engineering, science and technology experiments.

This little scientist’s first taste of microgravity research aboard a reduced gravity aircraft. Flight Day Minus 1 (Nov 16, 2013): Briefing, Test Readiness Review (TRR), and Load Up the Plane.

Reposted from https://blogs.nasa.gov/mission-ames/2013/12/16/this-little-scientists-first-taste-of-microgravity-research-aboard-a-reduced-gravity-aircraft-flight-day-minus-1-nov-16-2013-briefing-test-readiness-review-trr-and-load-up-the-plane/.

This is the first of a three-blog series (part 2 here, part 3 here) of this little scientist’s first foray into microgravity research. I participated in a research flight provided by the Zero-G corporation. To read more about their company go to https://www.gozerog.com/.

Zero-G operates a Boeing 727-200F aircraft, “G-Force One,” specially modified for reduced gravity operations. They provide opportunities for research flights (people and equipment) and also opportunities for you to experience zero-G (people). For experiment/research flights, you can apply directly to Zero-G where they organize a flight once they have enough researchers to fill a flight, or apply to NASA through their Flight Opportunities program https://flightopportunities.nasa.gov/, when NASA organizes the flight-manifest and Zero-G provides the flight platform. University students have additional opportunities to get flights through NASA’s Microgravity University,http://microgravityuniversity.jsc.nasa.gov/, with annual proposal calls. Had I known this when I was at school, I totally would have been a veteran flyer by now! Aircraft doing parabolic flight profiles are not restricted to the USA or to NASA. One list is provided here http://en.wikipedia.org/wiki/Reduced_gravity_aircraft.

The day before the flight, the flight director and series of “coaches” provided by the Zero G Corporation, came around to each of the research groups to look at the payloads and ascertain safety items. Prior to our arriving at our departure airport (in our case, Titusville, FL, but the “G-Force One” does fly from many airports, see their website), each team had to complete a Research Package, which contains the usual information such as mass, volume, power (including specifying “kill switch” items) and particular requests for gravity (the pilots can fly the airplane to simulate Martian and Lunar gravity in addition to near zero-G).  A series of weekly telecons were held in the weeks leading up to the flight to discuss interface needs and potential interference issues with others sharing the flight.

We meet the other teams for the first time. There were 6 experiments aboard this flight along with a BBC crew for the show Stargazing Live. One of the BBC presenters, Dara Ó Briain, joined us on this flight. So Kimberly gets to be an (unnamed) extra on TV show!

The other research experiments included (1) CubeSat solar-sail deployment mechanism, (2) testing a new IMU (inertia measurement unit), (3) evaluating sedimentations under Martian gravity, (4) Australian company developing ways to brew, and pour beer in zero-gravity, and (5) a mystery payload as it was under a NDA (non-disclosure agreement) with Zero G. Our Box of Rock science experiment (BORE) plus the SWUIS (Southwest Universal Imaging System) operations experiment rounded us to a total of 7 unique experiments. It was very fun getting to know the other experimenters, many who were also first timers!

suitcase_science

(left) Our two payloads in the hotel before driving out to the airport. (right) Easy to transport our suitcase-sized payloads to the airfield.

settingup_trr

(left) Heading to the Test Readiness Review (TRR). Payloads coming in cardboard boxes, pelican cases and roller bags. (right) Julia Laystrom-Woodard, a senior engineer from CU Aerospace (another first time flyer like me) describing her solar sail deployment experiment at the TRR.

The Test Readiness Review (TRR) was held in a hangar near the plane. Each group had to show the Zero-G staff the exact payload and configuration and describe the experiment in more detail and call attention to unique configurations and requests. In our case, we were going to use both blue tooth and wireless communication to monitor our payloads during the flight, so this meant an interference test with the airplane would need to be scheduled later in the day. The reviewers were mainly concerned about safety, safety to ourselves, safety to fellow passengers and equipment nearby, and safety to the airplane. For example, we had filed down edges on our payload, but due to the free-floating nature of the experiment, they requested we “foam our edges.” As we had experienced flyers with us, we had brought foam pipe-insulation with us and, of course, the ever-essential duct tape.  However, we had to send a few members of our team over lunch to Home Depot to pick up some more. Duct tape and foam were the order of the day!

assembling_bore

Assembling BORE for the TRR. No shortage of duct tape and foam.

assembling_swuis

Assembling SWUIS and showing the layout of the tethering cables.

After the TRR, we waited for our time to set up in the aircraft. Along the floor of the aircraft are designated hook points. All payloads need to be secured to the floor with straps. For those that are “free-floating” they need to be secured within a storage box, whose dimensions were given to use prior. In our case, we configured our two free floating payloads to the size of two suitcase volumes. With our team of six, we identified where wanted our “footholds” to help keep us in place. These footholds were manually installed by the Zero-G folks and torqued down.

loading_up-768x1024

Loading up the plane via the back door to this Boeing 727. Not shown is that is another way to enter the aircraft via a large cargo bay door that can be opened on the side of the fuselage for larger payloads. For this flight, all the researcher’s experiments were all hand carried and broken down into smaller suitcase sized parts.

setting_up_plane

(left) Securing one of the other experiments to the floor of the aircraft. You can see the large cargo door opened to the left. It was a hot day in Titusville, FL so it made setting up a bit cooler to have air circulating. (middle) Using loads of Velcro to provide “temporary” binding for our free-floating experiments during the high-G times. (right) Setting up and installing the foot straps (red cords) to specific locations on the  floor.

During this setup we learned where each group would be physically situated on board and we could re-assess interference items not previously considered. Each experimenter group was assigned a 10 foot x10 foot area on the plane and were designated by the color of their socks. We were the “grey team” and had a spot about half-way down the aircraft near the exit windows.

After the configuration of all the mechanical hold-down areas, we did our powered tests and also checked for interference. All looked good. Anything we would bring the next day to board the flight had to fit in our flight suit. We next stowed our two suitcase payloads for takeoff and headed back to the hotel for a team briefing and light dinner.

The next blog entries follow the flight day.

The Pluto science community is rich and diverse, just like its target of study: the ever-fascinating Pluto and its satellite moons.

Reposted from https://blogs.nasa.gov/mission-ames/2013/07/27/the-pluto-science-community-is-rich-and-diverse-just-like-its-target-of-study-the-ever-fascinating-pluto-and-its-satellite-moons/.

This blog entry concludes my series of talk summaries for the July 22-26, 2013 Pluto Science Conference, “The Pluto System on the Eve of Exploration by New Horizons: Perspectives and Predictions.” You can read more about the conference and browse through the abstracts at the conference website.

In his closing comments, Alan Stern (SwRI), the lead scientist (Principal Investigator) for NASA’s New Horizons fly-by mission to Pluto, told us about the last time a scientific discussion gathering specifically about Pluto occurred. It was twenty years ago, a 3-day meeting in July 1993, in Flagstaff, Arizona. The talks and presentations from that workshop led to ten contributed papers in a special issue in 1994 in Icarus (Vol 108, Issue 2) and, in 1997, the publication of a book entitled “Pluto and Charon” by The University of Arizona Press.

When the group gathered in 1993, the 1989 Voyager 2 fly-by of Neptune’s moon Triton’s was still “fresh data”, the prime Pluto-Charon “Mutual Events Period” of the 1985-1990 had just ended, and the Hubble Space Telescope (HST) would be soon coming back on-line with its fixed optics (the 1st HST servicing mission would occur in December 1993). It was a busy time for the Pluto science community.

Some attendees at the open workshop meeting on Pluto & Charon in July 1993, Flagstaff, Arizona.

This five-day July 2013 meeting has demonstrated that the quest to better understand Pluto and its environment is a very rich and diverse field of study. With each new data set about Pluto and its companions, surprises are uncovered and new questions are posed. When the New Horizons spacecraft reaches the Pluto system in July 2015, a true “first encounter experience,” its on-board suite of modern instruments will transform our current-best resolution ~800 km/pixel (from Hubble observations) to a resolution of 0.46 km/pix (hemisphere) with 0.09 km/pix (regional) resolution with the LORRI instrument. You can be certain there will be a lot more surprises in store. Combining this with new and unique data sets from New Horizons’ particle & dust instruments and the UV and IR spectrometers, our understanding of the Outer Solar System will find a new grounding.

With 103 oral talks + 30 posters + 13 “topical sessions” this was a jammed pack week of sharing old information, sharing new data from the past few years, sharing “hot off the press data” (it’s Pluto observing season right now and during the conference attendees were doing observations of Pluto & Charon with IRTF, Keck and other telescopes, remotely or with their colleagues at the telescopes), identifying what computations or experiments are needed before the 2015 encounter, and in some cases, providing predictions of what might be detected at Pluto and Charon. Several papers presented at this conference will be submitted to the Icarus journal.

Attendees at the “The Pluto System on the Eve of Exploration by New Horizons: Perspectives and Predictions,” held July 22-26, 2013, in Laurel, MD. The topical sessions covered Atmospheres, Charon, Dust & Rings, Interiors, Kuiper Belt Context, Laboratory Studies, Magnetosphere, New Horizons Mission, Origins, Satellites, Surface Composition, Surface Geology, and Surface-Atmosphere Interactions.

The stage is set for a summer 2017 Pluto Science Conference. New Horizon’s flyby of the Pluto System is on July 14, 2015, but it will take a bit over a year for all the data to come down losslessly (i.e. without compression). Deliveries to the NASA’s Planetary Data System are planned in 2016 and early 2017.

I hope you enjoyed this blog series reporting on these intriguing topics. You can follow the New Horizons mission status at any time by visiting the New Horizons Mission Website at http://pluto.jhuapl.edu/ and http://www.nasa.gov/mission_pages/newhorizons/main/index.html.

To Pluto and Beyond!!!!

Pluto Exotica. Atoms. Pick Up Ions. Bow Shocks. Suprathermal Tails. X-Rays. UV airglow.

Reposted from https://blogs.nasa.gov/mission-ames/2013/07/27/pluto-exotica-atoms-pick-up-ions-bow-shocks-suprathermal-tails-x-rays-uv-airglow/.

The morning of the last day of this week’s July 22-26, 2013, Pluto Science Conference opened up the discussion with outer atmosphere (far out) and magnetosphere (really far out) talks.

Fran Bagenal (University of Colorado) started the session with a talk on “The Solar Wind Interaction with Pluto’s Escaping Atmosphere.” Pluto’s interaction with the solar wind was first suggested in 1981 by Larry Trafton. There are two generally predicted regimes of what this interaction might look like: (1) Venus-like (small escape rate) and (2) Comet-Like (high escape rate). A key parameter distinguishing the two is what the atmospheric escape rate might be, that is, how many atmospheric molecules (assumed to be nitrogen) are escaping from Pluto, no longer being bound by gravity. Current estimates for the escape rate, based on a number of approaches, notably a recent one by Darrell Strobel (2012), have this number at 2-5×1027molecules/sec.  This is large enough to suggest Pluto will appear to be “comet-like” in its interaction with the solar wind. However, we need to wait until 2015 for the New Horizons fly-by with their in-situ particle instruments SWAP & PEPSSI to make the interaction measurements.

When describing the Pluto System in terms of solar wind interaction, Fran Bagenal showed this image, which superimposed one of Darrell Strobel’s atmospheres (characterized with an exobase at 12 Pluto radii). Pluto becomes a “large object” for interaction with the solar wind.

When solar wind particles (protons) interact with the Pluto atmosphere, their path through space is bent along the magnetic field lines, and to convert momentum, pickup ions (neutral hydrogen atoms from the heliosphere that undergo a collisional charge-exchange interaction with solar wind protons, get ionized, are “picked up” by the solar magnetic field) get tossed onto new trajectories. Those ions are charged and will begin to rotate and follow electrical field lines. Where do the ionized particles go? A weak magnetic field will create large gyro-radii of pick-up ions which can extend millions of kilometers upstream of Pluto.  This is best modeled with a kinetic interaction.

Peter Delamere (University of Alaska, Fairbanks) spoke in greater detail about “The Atmosphere-Plasma Interaction: Hybrid Simulations.” Plasma interaction is an atmospheric diagnostic tool. Neutral gases are not easily picked up, but ions and how they interact with the solar wind can be detected with in-situ instruments such Hew Horizons’ SWAP and PEPSSI. He discussed his model plasma interaction mode, which was validated using Comet 19P/Borrelly that had been visited by Deep Space 1 on Sept 22, 2001.

Example of Comet 19B/Borelly environment time vs. energy reveals the structure of the interaction between a comet and the solar wind. The X-axis is time from closes approach, with the Y-axis energy. The color code is the number of particles counted by the PEPE instrument aboard Deep Space 1. This is similar to what the data is expected to look at for Pluto when New Horizons reaches it in 2015, however, the solar wind at 33 AU may be more extended and more diffuse and therefore the signal strength (in terms of counts) will be much less.

If we can understand where the bow shock forms, this becomes a diagnostic of the atmosphere, and if indeed the exosphere extends out to 10 Pluto radii as suggested by recent work by Darrell Strobel (2012) and other models, then this is a sizable ‘obstacle.’ But is it inflated enough to form a bow shock? Peter Delamere thinks so. He stepped us through a variety of simulations. One of the simulations predicts a partial bow shock. If you increase Qo (the escape rate parameter, predicted to be in the 2-5×1027 N2 molecules) or increase magnetic field strength you can create a full bow shock. Future work includes adding the pickup part of the solar wind model as input.  If there is a very slow momentum transfer, perturbed flow could extend out to an AU.

Simulations predict all sorts of shock structures (Mach cones, bow shocks), but these structures depend on the escape rate parameter.

Example of a plasma interaction mode for three escape rates, decreasing from right to left. This is a slide in space of plane vs. distance from.  The white lines are sample solar wind proton trajectories. The color scale indicates ion density. The solar wind (and hence, the direction from the sun) is incident from the left. Pluto is at (0,0).

Predictions at Pluto. He anticipates significant asymmetry. The predicted bow show could be as far as 500 Pluto radii.

Heather Elliot (SwRI, San Antonio) in her talk “Analysis Techniques and Tools for the New Horizons Solar Wind around Pluto” described the New Horizons SWAP instrument and the different rate modes (sampling rate and scan types) it will be using during the 2015 encounter.

Measurement of the solar wind taken with the SWAP instrument aboard New Horizons during the last 6 years of cruise. This data set covers AU=10 (Saturn distance) out to AU=23 in 2012. The solar wind is mostly protons (H+). The second most abundant species are alphas (He++). The colors are the intensity of species. The vertical axes are energy per charge units and the horizontal axis is time.

Fitting the SWAP data to a solar wind model requires making adjustments for view angle and during the hibernation period, when they do not have attitude information, they have modeled the Sun-probe-Earth angle to estimate the attitude and this works well to fit their data.

John Cooper (NASA Goddard) spoke about the  “Heliospheric Irradiation in Domains of Pluto System and Kuiper Belt.”  He is interested in computing the “radiolytic” dosage onto bodies in the outer solar system (that is, the effect of how molecules break down or change molecular band structure due to the influence of radiation, such as by cosmic rays, particles, UV, etc.). For this he needs measurements of the particle flux at large AU.  New Horizons joins its cousins Voyager 1 & 2, Pioneer 10 & 11 and Ulysses in exploring the outer solar system.

spacecraft_outersolar

Location of the NH spacecraft (orange on the left, purple on the right) for two different views of the solar system. Also plotted are deep space missions Voyager and Pioneer, among many. The left view is s top down view of the solar system with the Sun at (0,0), the axes are in AU, where 1 AU (Astronomical Unit) is the distance between the Earth and Sun. The right is a view of time vs. latitude for the crafts. Comparative data sets to New Horizons, which travels along the solar ecliptic, are Pioneer 10 and early Voyager 2 data.

He showed computations of irradiation dosage when applying those particle rates measured by New Horizon’s PEPSSI instrument and instruments aboard Voyager 2 and Pioneer 10.

He maintains a database of all particle instrument flux measurements at the Virtual Energetic Particle Observatory http://vepo.gsfc.nasa.gov.

Thomas Cravens (JHU/APL) with ”The Plasma Environment of Pluto and X-Ray Emission: Predictions for New Horizons,” asked “What happens when you get to within 1000 km of Pluto?“  Pluto is anticipated to be “Comet-Like” in its interaction with the solar wind, however when you get closer to Pluto (around 1000 km), it may more closely resemble “Venus-like” interaction. He is trying to compute where the charge-exchange boundary could be, probably around r~5000km. This is boundary between the kinetic (r>5000km) and fluid (r<5000 km) regimes, essentially probing the ionosphere regime of Pluto.

Switching to slightly lower energies, Casey Lisse (JHU/APL) gave a talk on “Chandra Observations of Pluto’s Escaping Atmosphere in Support of New Horizons.” X ray interactions (charge exchange, scattering and auroral precipitation) require an extensive neutral atmosphere, which is what is expected at Pluto. Interaction of solar wind with comets has consistently shown X-ray emission. He expects to see X-ray emission from Pluto. If detected it would tell us about the size and mass of Pluto’s unbound atmosphere. The best time to look for x-rays at Pluto is about 100 days after a large CME (corona mass ejection) event, which is about the time it takes for CME to get to Pluto at 33 AU.

He and his colleagues applied for, and got, time on NASA’s Chandra X-ray telescope. On Chandra, Pluto & Charon will appear to fill one Chandra pixel using the Chandra HRC instrument.  He ended his talk suggesting that looking at background counts with the LORRI and RALPH CCDs might serve as a poorman’s x-ray detector. It is also possible that PEPSSI background counts could be used to infer presence of lower X-rays.

Kandi Jessup (SwRI) gave a talk addressing the “14N15N Detectability at Pluto.” We care about14N15N because it can be used to determine the 15N to 14N isotropic fractionation. This can help tell us about the evolution of Pluto’s atmosphere. Learning about Pluto’s atmospheric evolution history also provides vital suggestions for the evolution of equivalent TNOs (Trans-Neptunian Objects) and other objects in the Kuiper Belt, and hence, the outermost parts of our Solar System

The measurement will be the UV spectral observations during the solar occultation of Pluto by the Alice instrument during the New Horizons fly-by. N2 is the dominant absorber between 80-100nm. To identify the molecule 14N15N they use an atmosphere model from Krasnopolsky & Cruikshank (1999). That model does not have a troposphere. Next they need absorption cross-sections (a parameter that quantifies the ability of a molecule to absorb a photon of a particular wavelength) for 14N2 and 14N15N. 14N2 is the more dominant species and they are trying to find a very small percentage for 14N15N. Using these simulations they anticipate the Alice instrument will be sensitive enough to detect at least a 14N15N to 14N2 ratio of 0.3%. They will be look at the UV spectrum between 88 and 90 nm where the 15N lines spectrally shifted from 14N line. 14N15N to 14N2 ratio has been measured on Mars (0.58%), Titan (0.55%), and Earth (0.37%). What ratio will Pluto have? New Horizons data will hopefully tell us.

Randy Gladstone (SwRI, San Antonio) spoke about “Ly-alpha at Pluto.” Pluto ultraviolet (UV) airglow line emissions will be very weak, except at HI Lyman-alpha (Ly-a). Ly-a at Pluto could have both a solar (Sun) and an interplanetary (IPM/interplanetary medium) source. Ly-a should be scattered by Hydrogen atoms in Pluto’s atmosphere.  He uses the Krasnopolsky & Cruikshank (1999) Pluto atmosphere model that predicts the number of Hydrogen atoms at altitude. There are several observations near Pluto closest approach planned with the New Horizons Alice instrument to measure Lyman-alpha emissions.  This data will provide information about the vertical distribution of H and CH4 in Pluto’s atmosphere. Observation of the IPM Lyman-alpha source will be unique and provide important information to model Pluto’s photochemistry, especially for the nightside and winter pole region.

Randy Gladstone (SwRI, San Antonio) ended the session with a talk about “Pluto’s Ultraviolet Airglow.” He presented a model by Michael Stevens (Naval Research Lab), which has been used to explain the Cassini UVIS (Ultraviolet Imaging Spectrograph) observation of UV airglow at Titan over the 80-190 nm wavelength, emissions arising from processes on N2 (Stevens et al 2011). The model is called AURIC, the Atmospheric Ultraviolet Radiance Integrated Code. This model will be used for interpreting Pluto atmosphere data taken at UV wavelength with the New Horizons Alice instrument.

If Pluto was not already an exotic place to visit with all the predictions about its formation, its interior, its surface, it surface-atmosphere interaction, its composition, etc., it certainly will prove to be an amazing place if any or all of these predicted upper atmosphere and mesosphere molecular species, ions, and high energy particles are measured with the New Horizons spacecraft!