vendredi 9 novembre 2018

Crew Ends Week Researching Space Physics, Biology and Time

ISS - Expedition 57 Mission patch.

November 9, 2018

A crew of three from around the world are heading into the weekend aboard the International Space Station. The Expedition 57 trio from the United States, Russia and Germany studied a variety of space phenomena today including physics, biology and time perception.

Flight Engineer Serena Auñón-Chancellor joined Commander Alexander Gerst for eye checks first thing Friday morning. The duo then split up for a science-filled day and preparations for the next U.S. cargo mission.

Serena spent most of the day in the Japanese Kibo lab module mixing protein crystal samples and stowing them in an incubator for later analysis. She moved on to a little space gardening for the VEG-03 study before stowing gear that sequences ribonucleic acid, or RNA, from unknown microbes living in the station.

Image above: Flight Engineer Serena Auñón-Chancellor checks on plants being grown for botany research aboard the International Space Station. NASA is exploring ways to keep astronauts self-sufficient as humans learn to live longer and farther out into space and beyond low-Earth orbit. Image Credit: NASA.

Serena also found time to set up a command panel for communications with a Cygnus cargo craft when it arrives to resupply the station Nov. 18. The resupply ship from U.S. company Northrop Grumman is being packed and readied for launch atop an Antares rocket Nov. 15 at 4:49 a.m. EST. from Wallops Flight Facility in Virginia.

Gerst spent over an hour in the European Columbus lab module today researching how astronauts perceive time in space including its physical and mental impacts. The German astronaut from ESA (European Space Agency) also configured a specialized microscope for more protein crystal observations.

International Space Station (ISS). Animation Credit: NASA

Flight Engineer Sergey Prokopyev from Roscosmos continued his week-long research exploring complex plasmas, or ionized gases produced by high temperatures. The Russian experiment may benefit space physics research and improve spacecraft designs. The cosmonaut also swapped fuel bottles inside the Combustion Integrated Rack to maintain ongoing flame and gas research aboard the station.

Related links:

Expedition 57:

Protein crystal samples:



Sequences ribonucleic acid (RNA):

Perceive time in space:

Protein crystal observations:

Complex plasmas:

Combustion Integrated Rack:

Space Station Research and Technology:

International Space Station (ISS):

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Catherine Williams.

Best regards,

Small Tissue Chips in Space a Big Leap Forward for Research

CASIS - Chips in Space patch.

Nov. 9, 2018

A small device that contains human cells in a 3D matrix represents a giant leap in the ability of scientists to test how those cells respond to stresses, drugs and genetic changes. About the size of a thumb drive, the devices are known as tissue chips or organs on chips.

Image above: Made of flexible plastic, tissue chips have ports and channels to provide nutrients and oxygen to the cells inside them. Image Credit: NASA.

A series of investigations to test tissue chips in microgravity aboard the International Space Station is planned through a collaboration between the National Center for Advancing Translational Sciences (NCATS) at the National Institutes for Health (NIH) and the Center for the Advancement of Science in Space (CASIS) in partnership with NASA. The Tissue Chips in Space initiative seeks to better understand the role of microgravity on human health and disease and to translate that understanding to improved human health on Earth.

“Spaceflight causes many significant changes in the human body,” said Liz Warren, associate program scientist at CASIS. “We expect tissue chips in space to behave much like an astronaut’s body, experiencing the same kind of rapid change.”

Many of the changes in the human body caused by microgravity resemble the onset and progression of diseases associated with aging on Earth, such as bone and muscle loss. But the space-related changes occur much faster. That means scientists may be able to use tissue chips in space to model changes that might take months or years to happen on Earth.

Image above: The insignia representing the collaboration between CASIS and NIH (NCATS and NIBIB) for the Tissue Chips in Space investigations to the International Space Station National Laboratory. Image Credit: CASIS.

Also called a micro-physiological system, a tissue chip needs three main properties, according to Lucie Low, scientific program manager at NCATS. “It has to be 3D, because humans are 3D,” she explained. “It must have multiple, different types of cells, because an organ is made up of all kinds of tissue types. And it must have microfluidic channels, because every single tissue in your body has vasculature to bring in blood and nutrients and to take away detritus.”

“Tissue chips give cells a home away from home,” Warren said. They mimic the complex biological functions of specific organs better than a standard, 2D cell culture.

“Essentially, you get a functional unit of what human tissues are like, outside of the body,” said Low. “It’s like taking a little bit of you, putting it into a pot and looking at how your cells respond to different stresses, different drugs, different genetics and using that to predict what they would do in your body.”

One potential application of tissue chips is in development of new drugs. Approximately 30 percent of promising medications are found to be toxic in human clinical trials despite favorable pre-clinical studies in animal models. About 60 percent of potential drug candidates fail due to lack of efficacy, meaning the drug does not have the intended effect on a person.

“There is a need in the drug development process to have better models to predict responses of the human body and to gauge toxicity much earlier in the process, as well as to check that a potential drug actually does what it’s supposed to without adverse side effects,” Low said. As accurate models of the structure and function of human organs, such as the lung, liver and heart, tissue chips provide researchers a model for predicting whether a candidate drug, vaccine or biologic agent is safe in humans more quickly and effectively than current methods.

Tissue Chips in Space builds on microfluidics knowledge gained in previous space station investigations, Warren said, but also required creating new, as yet untested, hardware and systems. For one thing, the system had to be automated as much as possible.

Houston We Have a Podcast:

“We wanted to simplify everything for spaceflight, so astronauts essentially just have to plug in a box on the space station, without doing anything hands-on with syringes or fluids,” she said. Engineers also had to miniaturize complex, large equipment used to maintain proper environmental conditions for the chips. That hardware, the size of a refrigerator in laboratories on Earth, takes up about as much room as a shoebox in space.

The microfluidics presented unique challenges, such as dealing with formation of bubbles. On Earth, bubbles float to the top of a fluid and escape, but special mechanisms are needed to remove them in microgravity.

The automation and miniaturization accomplished for Tissues Chips in Space contributes to standardization of tissue chip technology, which advances research on Earth as well. “Now we have a tool that can be sent anywhere on the planet,” Low said.

On Earth, scientists are working on linking several organ chips together to mimic the whole body. That could enable precision medicine, or customized disease treatments and prevention that take into account an individual’s genes, environment and body.

This first phase of Tissue Chips in Space includes five investigations. An investigation of immune system aging is planned for launch on the SpaceX CRS-16 flight, scheduled for mid-November. The other four, scheduled to launch on SpaceX CRS-17 or subsequent flights, include lung host defense, the blood-brain barrier, musculoskeletal disease and kidney function. These first flights test the effects of microgravity on the tissue chips and demonstrate the capability of the automated system.

Tissue Chips In Space

All five investigations make a second flight about 18 months later to further demonstrate functional use of the model, such as testing potential drugs on the particular organs. In addition, four more projects are scheduled for launch in summer 2020, including two on engineered heart tissue to understand cardiovascular health, one on muscle wasting and another on gut inflammation.

Ultimately, Warren said, the technology could allow astronauts going into space to take along personalized chips that could be used to monitor changes in their bodies and to test possible countermeasures and therapies. That would be a really big leap toward keeping astronauts healthy on missions to deep space.

Related links:

National Center for Advancing Translational Sciences (NCATS):

National Institutes for Health (NIH):

Center for the Advancement of Science in Space (CASIS):

Tissue Chips in Space:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/JSC/International Space Station Program Science Office/Melissa Gaskill.


Jovian Close Encounter

NASA - JUNO Mission logo.

Nov. 8, 2018

A multitude of magnificent, swirling clouds in Jupiter's dynamic North North Temperate Belt is captured in this image from NASA's Juno spacecraft. Appearing in the scene are several bright-white “pop-up” clouds as well as an anticyclonic storm, known as a white oval.

This color-enhanced image was taken at 1:58 p.m. PDT on Oct. 29, 2018 (4:58 p.m. EDT) as the spacecraft performed its 16th close flyby of Jupiter. At the time, Juno was about 4,400 miles (7,000 kilometers) from the planet's cloud tops, at a latitude of approximately 40 degrees north.

Citizen scientists Gerald Eichstädt and Seán Doran created this image using data from the spacecraft's JunoCam imager.

JunoCam's raw images are available for the public to peruse and to process into image products at:  

More information about Juno is at: and

Image, Text,  Credits: NASA/Tony Greicius/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran.


Space Station Science Highlights: Week of November 5, 2018

ISS - Expedition 57 Mission patch.

November 9, 2018

The Expedition 57 crew members aboard the International Space Station said farewell to a Japanese resupply ship Wednesday, and are getting ready to welcome U.S. and Russian space freighters in less than two weeks. In addition to preparation for the arrival of cargo vehicles, the crew spent time maintaining space-grown plants, continuing research on DNA and RNA sequencing in microgravity and studying the formation of plasma crystals in a weightless environment.

Image above: The H-II Transfer Vehicle-7 (HTV-7) of the Japan Aerospace Exploration Agency (JAXA) over the coast of Chile. Image Credit: NASA.

Learn about some of the science launching aboard the Northrop Grumman Commercial Resupply-10 mission here:

Here’s a look at some of the science conducted this week aboard the orbiting lab:

Direct RNA sequencing initialized

Biomolecule Extraction and Sequencing Technology (BEST) seeks to advance use of sequencing in space in three ways: identifying microbes aboard the space station that current methods cannot detect, assessing microbial mutations in the genome because of spaceflight and performing direct RNA sequencing.

This week, part three of the experiment was completed to demonstrate direct RNA sequencing with the MinION miniature DNA sequencer.

Learn more about the BEST investigation here:

Investigation monitors plant growth progression

Future long-duration missions into the solar system will require a fresh food supply to supplement crew diets, which means growing crops in space.

The Veg-03 investigation expands on previous validation tests of the new Veggie hardware, which crew members used to grow cabbage, lettuce and other fresh vegetables in space. The latest crop marks the first time that Red Russian Kale and Dragoon Lettuce are being grown on station.

Image above: Plant pillows containing Red Russian Kale and Dragoon Lettuce are currently growing within the Veggie plant growth facility. Image Credit: NASA.

This week, the crew placed markings on the watering syringes in preparation for future plant watering and checked Veg-03 plants for growth progression, watering them as necessary.

Investigation studies plasma formation in space

Plasmas are found throughout the universe, from the interstellar medium to the heat shields of spacecraft re-entering Earth's atmosphere. Understanding how plasma crystals form in microgravity could shed light on plasma phenomena in space. The Plasma Kristall-4 investigation (PK-4) is a scientific collaboration between the European Space Agency (ESA) and the Russian Federal Space Agency (Roscosmos), performing research in the field of "Complex Plasmas": low temperature gaseous mixtures composed of ionized gas, neutral gas, and micron-sized particles.

This week, as a part of PK-4, the crew:

- Performed video setup and checkout, connected gas supply hoses (Argon and Neon) and verified valve functionality.

- Initiated the second of four experiment runs with the start of Particle Trapping via the European Physiology Module (EPM) laptop commanding using Neon Gas. This will allow clouds of particles to be captured inside the PK-4 chamber:

- Performed particle trapping activities using the Argon Gas line. Experiment was initiated via the EPM laptop.

- Exchanged the hard drive containing data from experiment run two and inserted a new hard drive for the third run. The crew then reconfigured the gas chamber from Neon to Argon gas usage.

Other work was done on these investigations:

- Meteor is a visible spectroscopy instrument used to observe meteors in Earth orbit:

- JAXA LT PCG contributes to the development of new drugs by revealing disease-related protein structure, and to the production of new catalysts for the environmental and energy industries:

- The Advanced Plant Habitat Facility (Plant Habitat) is a fully-automated facility used to conduct plant bioscience research and provides a large, enclosed, environmentally-controlled chamber aboard the space station:

- BCAT-CS studies dynamic forces between sediment particles that cluster together:

- Food Acceptability examines changes in how food appeals to crew members during their time aboard the station. Acceptability of food – whether crew members like and actually eat something – may directly affect crew caloric intake and associated nutritional benefits:

Space to Ground: Surviving the Plunge: 11/09/2018

Related links:

Expedition 57:

Biomolecule Extraction and Sequencing Technology (BEST):



Plasma Kristall-4 investigation (PK-4):

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/Vic Cooley, Lead Increment Scientist Expeditions 57/58.

Best regards,

Oxia Planum favoured for ExoMars surface mission

ESA & ROSCOSMOS - ExoMars Mission patch.

9 November 2018

The ExoMars Landing Site Selection Working Group has recommended Oxia Planum as the landing site for the ESA-Roscosmos rover and surface science platform that will launch to the Red Planet in 2020.

Oxia Planum texture map

The proposal will be reviewed internally by ESA and Roscosmos with an official confirmation expected mid-2019.

At the heart of the ExoMars programme is the quest to determine if life has ever existed on Mars, a planet that has clearly hosted water in the past, but has a dry surface exposed to harsh radiation today.

ExoMars rover 360

While the ExoMars Trace Gas Orbiter, launched in 2016, began its science mission earlier this year to search for tiny amounts of gases in the atmosphere that might be linked to biological or geological activity, the rover will drive to different locations and drill down to two metres below the surface in search of clues for past life preserved underground. It will relay its data to Earth through the Trace Gas Orbiter.

Both landing site candidates – Oxia Planum and Mawrth Vallis – preserve a rich record of geological history from the planet’s wetter past, approximately four billion years ago. They lie just north of the equator, with several hundred kilometres between them, in an area of the planet with many channels cutting through from the southern highlands to the northern lowlands. Since life as we know it on Earth requires liquid water, locations like these include many prime targets to search for clues that may help reveal the presence of past life on Mars.

“With ExoMars we are on a quest to find biosignatures. While both sites offer valuable scientific opportunities to explore ancient water-rich environments that could have been colonised by micro-organisms, Oxia Planum received the majority of votes,” says ESA’s ExoMars 2020 project scientist Jorge Vago. 

“An impressive amount of work has gone into characterising the proposed sites, demonstrating that they meet the scientific requirements for the goals of the ExoMars mission. Mawrth Vallis is a scientifically unique site, but Oxia Planum offers an additional safety margin for entry, descent and landing, and for traversing the terrain to reach the scientifically interesting sites that have been identified from orbit.”

The Landing Site Selection Working Group also emphasised that the discoveries generated during the landing site selection process are essential to guide the science operations of the ExoMars rover.

ExoMars landing sites in context

The recommendation was made today following a two-day meeting held at the National Space Centre in Leicester, UK, which saw experts from the Mars science community, industry, and ExoMars project present and discuss the scientific merits of the sites alongside the engineering and technical constraints.

The quest to find the perfect landing site began almost five years ago, in December 2013, when the science community was asked to propose candidate locations. Eight proposals were considered in the following April, with four put forward for detailed analysis in late 2014. In October 2015, Oxia Planum was identified as one of the most compatible sites with the mission requirements – at that time with a 2018 launch date in mind – with a second option to be selected from Aram Dorsum and Mawrth Vallis. In March 2017, the down-selection identified Oxia Planum and Mawrth Vallis as the two candidates for the 2020 mission, with both undergoing a detailed evaluation over the last 18 months.

ExoMars landing site candidates – elevation

On the technical side, the landing site must be at a suitably low elevation level, so that there is sufficient atmosphere and time to help slow the landing module’s parachute descent. Then, the 120 x 19 km landing ellipses should not contain features that could endanger the landing, the deployment of the surface platform ramps for the rover to exit, and the subsequent driving of the rover. This means scrutinising the region for steep slopes, loose material and large rocks.

On the science side, the analysis had to identify sites where the rover could use its drill to retrieve samples from below the surface, and to define possible traverses it could make up to 5 km from its touchdown point in order to reach the maximum number of interesting locations.

A slice of Oxia Planum

Oxia Planum lies at the boundary where many channels emptied into the vast lowland plains. Observations from orbit show that the region exhibits layers of clay-rich minerals that were formed in wet conditions some four billion years ago, likely in a large body of standing water. The channels that transported material into the lower-elevation ‘sink’, where the landing ellipse is situated, cover an area of 212 000 square kilometres. Layers of material that have been recently exposed through erosion are accessible from any of the touchdown points, giving a window into the early history of this area.

The minerals in Oxia Planum are representative of those found in a wide area around the region and so would provide insight into the conditions experienced at a global scale, putting constraints on the climate and habitability potential of Mars in this period.

Diverse aqueous episodes were followed by late volcanic activity, covering over the clay-rich deposits. Some lava material has resisted erosion until today, so the underlying materials may only have been exposed recently, initially protecting them from space radiation and later making them accessible to the rover and its analytical tools.

The landing ellipse has low elevation and contains very few topographic obstacles or challenging slopes.

How big is the ExoMars 2020 mission?

The ESA-led rover and Roscosmos-led surface science platform will launch in the 25 July–13 August 2020 launch window on a Proton-M rocket from Baikonur, Kazakhstan, and cruise to Mars in a carrier module containing a single descent module, arriving at Mars 19 March 2021.

The descent module will separate from the carrier shortly before reaching the martian atmosphere, and will use two large parachutes, along with thrusters and a damping system, to slow its descent to land on the Red Planet. While the rover will drive to different locations to analyse the surface and subsurface, the stationary platform will provide context imaging at the landing site, and long-term climate monitoring and atmospheric investigations.

Rover laboratory inside test chamber

The test campaign for preparing the rover for Mars is in full swing. The rover structural and thermal model test campaign has been successfully completed, and a six-week qualification test on the Analytical Laboratory Drawer – the onboard laboratory where the rover’s drill samples will be processed and analysed – is also nearing completion. The test included verifying the functionality of the sample processing mechanisms using Mars analogue samples under simulated Mars environment conditions – a low pressure, carbon dioxide atmosphere and a range of temperatures.

Tests to characterise the rover’s ability to tackle different types of terrain are also ongoing with the locomotion verification model. The delivery of flight hardware has also started, including the rover’s computer, battery and deployable mast, along with the majority of science instruments.

“Our ExoMars mission combines extreme performance with the novel design features of the rover, and we are looking forward to operating the first European mission on the surface of Mars,” says Francois Spoto, ExoMars Programme team leader.

“Landing on Mars has a long chain of risks, but thanks to the combined skills and expertise of European and Russian industries working with reliable technologies, we are focused on a safe landing.”

Notes for editors:

More information about the Landing Site Selection Working Group is available here:

Related links:

Robotic exploration of Mars:



ExoMars at IKI:

Images, Video, Text, Credits: ESA/IRSPS/TAS; NASA/JPL-Caltech/Arizona State University/NASA/JPL/University of Arizona/USGS/TAS-I/ESA/Jorge Vago/Francois Spoto/Markus Bauer.

Best regards,

jeudi 8 novembre 2018

U.S., Russian Spaceships Line Up for Launch After Japanese Vessel Departs

ISS - Expedition 57 Mission patch.

November 8, 2018

The Expedition 57 crew said farewell to a Japanese resupply ship Wednesday and is getting ready to welcome U.S. and Russian space freighters in less than two weeks. The trio first practiced International Space Station emergency procedures today then went on to space research and robotics training.

The U.S. company Northrop Grumman is getting its 10th Cygnus cargo craft packed and ready for launch atop an Antares rocket Nov. 15 at 4:49 a.m. EST. Russia will launch its 71st station resupply mission aboard a Progress spaceship the next day at 1:14 p.m.

Image above: Japan’s HTV-7 resupply ship is pictured after it was released from the grips of the Canadarm2 robotic arm. Both the HTV-7 and the International Space Station were orbiting about 254 miles above the Pacific Ocean and about 311 miles west of Baja California. Image Credit: NASA.

Both resupply ships are due to arrive at the station Sunday Nov. 18 just 10 hours apart. The Cygnus will get there first following its head start. Commander Alexander Gerst assisted by Flight Engineer Serena Auñón-Chancellor will capture the American vessel with the Canadarm2 robotic arm at 4:35 a.m. A few hours later, cosmonaut Sergey Prokopyev will monitor the approach and automated docking of the Russian Progress 71 cargo craft to the Zvezda service module at 2:30 p.m.

All three crew members called down to mission controls centers in Houston and Moscow for a coordinated emergency drill today. The orbital residents practiced communication and decision-making skills while maneuvering along evacuation paths and locating safety gear.

Afterward, Gerst and Serena partnered up and reviewed next Sunday’s Cygnus approach and rendezvous procedures. Gerst will command the Canadarm2 to reach out and grapple Cygnus as Serena monitors the spaceship’s telemetry and data.

Prokopyev continued his science and maintenance duties in the orbital lab’s Russian segment. The cosmonaut explored the physics of plasma-dust crystals then conducted an eye exam in conjunction with doctors on Earth. Prokopyev also photographed the inside of the Zvezda and stowed radiation detectors.

Image above: The Frozen Wild Dnieper River. Curling snow drifts are magnified by the terrain around the 1,400 mile Dnieper River, flowing from Russia to the Black Sea. European Space Agency astronaut Thomas Pesquet, a member of the Expedition 50 crew, captured this image from the International Space Station on "Feb. 9th, 2017, saying, "winter landscapes are also magical from the International Space Station: this river north of Kiev reminds me of a Hokusai painting." Image Credits: NASA/ESA/Thomas Pesquet.

Each day, the International Space Station completes 16 orbits of our home planet as the crew conducts important science and research. Their work will not only benefit life here on Earth, but will help us venture deeper into space than ever before. Crew members on the space station photograph the Earth from their unique perspective, hovering 200 miles above us, documenting Earth from space. This record is crucial to how we see the planet changing over time, from human-caused changes like urban growth, to natural dynamic events such as hurricanes, and volcanic eruptions.

Related links:

Expedition 57:

Plasma-dust crystals:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Text, Credits: NASA/Mark Garcia/Nasreen Alkhateeb.

Best regards,

Parker Solar Probe Reports Good Status After Close Solar Approach

NASA - Parker Solar Probe patch.

Nov. 7, 2018

Image above: Illustration of Parker Solar Probe approaching the Sun. Image Credits: ​NASA/Johns Hopkins APL/Steve Gribben.

Parker Solar Probe is alive and well after skimming by the Sun at just 15 million miles from our star's surface. This is far closer than any spacecraft has ever gone — the previous record was set by Helios B in 1976 and broken by Parker on Oct. 29 — and this maneuver has exposed the spacecraft to intense heat and solar radiation in a complex solar wind environment.

“Parker Solar Probe was designed to take care of itself and its precious payload during this close approach, with no control from us on Earth — and now we know it succeeded,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate at the agency headquarters in Washington. “Parker is the culmination of six decades of scientific progress. Now, we have realized humanity’s first close visit to our star, which will have implications not just here on Earth, but for a deeper understanding of our universe.”

Mission controllers at the Johns Hopkins University Applied Physics Lab received the status beacon from the spacecraft at 4:46 p.m. EST on Nov. 7, 2018. The beacon indicates status "A" — the best of all four possible status signals, meaning that Parker Solar Probe is operating well with all instruments running and collecting science data and, if there were any minor issues, they were resolved autonomously by the spacecraft.

Image above: Members of the Parker Solar Probe mission team celebrate on Nov. 7, 2018, after receiving a beacon indicating the spacecraft is in good health following its first perihelion. Image Credits: NASA/Johns Hopkins APL/Ed Whitman.

At its closest approach on Nov. 5, called perihelion, Parker Solar Probe reached a top speed of 213,200 miles per hour, setting a new record for spacecraft speed. Along with new records for the closest approach to the Sun, Parker Solar Probe will repeatedly break its own speed record as its orbit draws closer to the star and the spacecraft travels faster and faster at perihelion.

First Perihelion: Into the Unknown - Parker Solar Probe

Video above: On Nov. 5, 2018, Parker Solar Probe achieved its first close approach to the Sun, called perihelion, a maneuver that exposed the spacecraft to intense heat and solar radiation. Video Credits: NASA/JHUAPL.

At this distance, the intense sunlight heated the Sun-facing side of Parker Solar Probe's heat shield, called the Thermal Protection System, to about 820 degrees Fahrenheit. This temperature will climb up to 2,500 F as the spacecraft makes closer approaches to the Sun — but all the while, the spacecraft instruments and systems that are protected by the heat shield are generally kept in the mid-80s F.

Parker Solar Probe's first solar encounter phase began on Oct. 31, and the spacecraft will continue collecting science data through the end of the solar encounter phase on Nov. 11. It will be several weeks after the end of the solar encounter phase before the science data begins downlinking to Earth.

Parker Solar Probe:

Images (mentioned), Video (mentioned), Text, Credits: NASA/Goddard Space Flight Center, by Sarah Frazier.


Multimessenger Links to NASA’s Fermi Mission Show How Luck Favors the Prepared

NASA - Fermi Gamma-ray Space Telescope logo.

Nov. 8, 2018

In 2017, NASA’s Fermi Gamma-ray Space Telescope played a pivotal role in two important breakthroughs occurring just five weeks apart. But what might seem like extraordinary good luck is really the product of research, analysis, preparation and development extending back more than a century.

On Aug. 17, 2017, Fermi detected the first light ever seen from a source of gravitational waves — ripples in space-time produced, in this event, by the merger of two superdense neutron stars. Just five weeks later, a single high-energy particle discovered by the National Science Foundation’s (NSF) IceCube Neutrino Observatory was traced to a distant galaxy powered by a supermassive black hole thanks to a gamma-ray flare observed by Fermi. 

“For millennia, light was our only source of information about the universe,” said Julie McEnery, the Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The recent discoveries connect light, our best-known cosmic courier, to gravitational waves and particles like neutrinos — new messengers delivering different kinds of information that we’re just beginning to explore.”

NASA's Fermi Mission Shows How Luck Favors the Prepared

Video above: Explore how more than a century of scientific progress with gravitational waves, gamma rays and neutrinos has helped bring about the age of multimessenger astronomy. Video Credits: NASA’s Goddard Space Flight Center.

Deep roots

The origins of these discoveries stretch back to cutting-edge research as long ago as 1887. That’s when physicists Albert Michelson and Edward Morley conducted an experiment to detect a substance, called the aether, which was postulated as a medium that permitted light waves to travel through space. As their experiment showed and many since have confirmed, the aether doesn’t exist. But the negative result proved to be one of the inspirations for Albert Einstein’s 1905 special theory of relativity. He generalized this into a full-fledged theory of gravity in 1915, one that predicted the existence of gravitational waves.

A century later, on Sept. 14, 2015, the NSF’s Laser Interferometer Gravitational-Wave Observatory (LIGO) detected these space-time vibrations for the first time as waves from the merger of two black holes reached Earth. In between came a steady stream of advances, including lasers, improved instrumentation and increasingly more powerful computers and software.

“Just as inventing the detector technologies has taken decades, so too has the theoretical and computational framework for analyzing and interpreting multimessenger observations,” said Tyson Littenberg, the principal investigator of the LIGO research group at NASA's Marshall Space Flight Center in Huntsville, Alabama. “We went through countless simulations to test new ideas and improve on existing algorithms so that we were prepared to make the most out of the first observations, and that basic research and development work continues.”

Until 2005, it wasn’t even possible to simulate in detail what happens when a pair of orbiting black holes coalesce. The breakthrough came when separate teams at Goddard and the University of Texas at Brownsville independently developed new computational methods that overcame all previous hurdles. An accurate understanding of gravitational-wave signals was one important step in evolving techniques designed to rapidly detect and characterize them.

Fermi and LIGO Graphs of Observations From Aug- 2017 Gravitational Wave

Video above: On Aug. 17, 2017, gravitational waves from a neutron star merger produced a signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO). The sound in this video represents the same frequencies as the combined stretching and squeezing caused by waves passing through the LIGO detectors at Hanford, Washington, and Livingston, Louisiana. Just 1.7 seconds later, a brief burst of gamma-rays — indicated by a ping — was seen by NASA's Fermi Gamma-ray Space Telescope. Video Credits: NASA's Goddard Space Flight Center, Caltech/MIT/LIGO Lab.

“Another fundamental development was the highly optimized analysis pipelines and information technology infrastructure that can compare the theoretical model with the data, recognize the presence of a signal, calculate the location of the source on the sky and format the information in a way that the rest of the astronomical community could use,” explained Tito Dal Canton, a NASA Postdoctoral Program Fellow and a member of a LIGO research group at Goddard led by Jordan Camp.

Astronomers need to know about short-lived events as soon as possible so they can bring to bear a wide array of telescopes in space and on the ground. Back in 1993, scientists at Goddard and Marshall began developing an automated system for distributing the locations of gamma-ray bursts (GRBs) — distant, powerful explosions that typically last a minute or less — to astronomers around the world in real time. Located at Goddard and led by Principal Investigator Scott Barthelmy, the Gamma-ray Coordinates Network/Transient Astronomy Network now distributes alerts from many space missions as well as ground-based instruments like LIGO and IceCube.

Ghost particles

The historical thread for neutrinos began with French physicist Henri Becquerel and his 1895 discovery of radioactivity. In 1930, after studying a radioactive process called beta decay, Wolfang Pauli suggested it likely involved a new subatomic particle, later dubbed the neutrino. We now know neutrinos possess little mass, travel almost as fast as light, come in three varieties and are among the most abundant particles in the universe. But because they don’t readily interact with other matter, neutrinos weren’t discovered until 1956.

In 1912, Victor Hess discovered that charged particles, now called cosmic rays, continually enter Earth’s atmosphere from every direction, which means space is filled with them. When cosmic rays strike air molecules, the collision produces a shower of particles — including neutrinos — that rains down through the atmosphere. Searching for astronomical neutrino sources meant placing experiments underground to reduce interference from cosmic rays and building very large detectors to tease out the weak signals of publicity-shy neutrinos.

Image above: On Sept. 22, 2017, the IceCube Neutrino Observatory at the South Pole, represented in this illustration by strings of sensors under the ice, detected a high-energy neutrino that appeared to come from deep space. NASA's Fermi Gamma-ray Space Telescope (center left) pinpointed the source as a supermassive black hole in a galaxy about 4 billion light-years away. It is the first high-energy neutrino source identified from outside our galaxy. Image Credits: NASA/Fermi and Aurore Simonnet, Sonoma State University.

Neutrinos produced by nuclear reactions inside the Sun’s core were first detected in 1968 thanks to an experiment using 100,000 gallons of dry-cleaning fluid located deep in a South Dakota gold mine. Discovering the next astronomical neutrino source would take another 19 years. Supernova 1987A, a stellar explosion in a nearby galaxy, remains the brightest and closest supernova seen in over 400 years and is the first for which the original star could be identified on pre-explosion images. Theorists anticipated that neutrinos, which escape a collapsing star more readily than light, would be the first signal from a new supernova. And hours before 1987A’s visible light arrived at Earth, experiments in Japan, the U.S. and Russia detected a brief burst of neutrinos, making the supernova the first source of neutrinos identified beyond the solar system.

“If none of these experiments was operating at the time, the neutrino signal would have passed by unnoticed,” said Francis Halzen, the principal investigator of IceCube, which is essentially a neutrino telescope build into a cubic kilometer of ice at the South Pole. “It isn’t enough to develop the technology, refine theories or even construct a detector. We need to be making observations as often as we can for the best chance of catching brief, rare and scientifically interesting events. Both Fermi and IceCube are operating continuously, making uninterrupted observations of the sky.”

Light fantastic

The third historical thread belongs to gamma rays, the highest-energy form of light, discovered in 1900 by the French physicist Paul Villard. When a gamma ray of sufficient energy interacts with matter, it provides a perfect demonstration of Einstein’s most famous equation, E=mc2, by instantly transforming into particles — an electron and its antimatter counterpart, a positron. Conversely, crash an electron and a positron together and a gamma ray results.

NASA’s Explorer 11 satellite, launched in 1961, detected the first gamma rays in space. In 1963, the U.S. Air Force began launching a series of satellites as part of Project Vela. These increasingly sophisticated satellites were designed to verify compliance with an international treaty that banned nuclear weapons tests in space or in the atmosphere. But starting in July 1967, scientists became aware the Vela satellites were seeing brief gamma-ray events that were clearly unrelated to weapons tests.

These explosions were GRBs, an entirely new phenomenon now known to mark the death of certain types of massive stars or the merger of orbiting neutron stars. NASA further explored the gamma-ray sky with the Compton Gamma Ray Observatory, which operated from 1991 to 2000 and recorded thousands of GRBs. Starting in 1997, critical observations by the Italian-Dutch BeppoSAX satellite proved that GRBs were located far beyond our galaxy. Compton was succeeded by NASA’s Neil Gehrels Swift Observatory in 2004 and Fermi in 2008, missions that continue exploring the high-energy sky and that follow up on LIGO and IceCube alerts.

“In the fields of observation, chance favors only the prepared mind,” noted Louis Pasteur, the French chemist and microbiologist, in an 1854 lecture. Supported by decades of scientific discoveries and technological innovation, the burgeoning field of multimessenger astronomy is increasingly prepared for its next stroke of luck.   

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy and with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

For more about NASA’s Fermi mission, visit:

Related links:

NASA Postdoctoral Program Fellow:

Gamma-ray Coordinates Network/Transient Astronomy Network:

Compton Gamma Ray Observatory:


Neil Gehrels Swift Observatory:

NASA’s Explorer 11:

NASA’s Neil Gehrels Swift Observatory:

Image (mentioned), Videos (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Francis Reddy.

Best regards,

Windy with a chance of magnetic storms – space weather science with Cluster

ESA - Cluster Mission logo.

8 November 2018

Space weather is no abstract concept – it may happen in space, but its effects on Earth can be significant. To help better forecast these effects, ESA’s Cluster mission, a quartet of spacecraft that was launched in 2000, is currently working to understand how our planet is connected to its magnetic environment, and unravelling the complex relationship between the Earth and its parent star.

Despite appearances, the space surrounding our planet is far from empty. The Earth is surrounded by various layers of atmosphere, is constantly bathed in a flow of charged particles streaming out from the Sun, known as the solar wind, and sends its own magnetic field lines out into the cosmos.

The Cluster quartet

This field floods our immediate patch of space, acting as a kind of shield against any extreme and potentially damaging radiation that might come our way. It also defines our planet’s magnetosphere, a region of space dominated by Earth’s magnetic field and filled with energy that is topped up by the solar wind and sporadically released into the near-Earth environment.

With this comes ‘weather’. We occasionally experience magnetic storms and events that disturb and interact with Earth’s radiation belts, atmosphere, and planetary surface. One of the most famous examples of this is the auroras that Earth experiences at its poles. These shimmering sheets of colour form as the solar wind disrupts and breaches the upper layers of our atmosphere.

Space weather has a real impact on our activities on Earth, and poses a significant risk to space-farers – robotic and human alike.

Sudden flurries of high-energy particles emanating from the Sun can contain up to 100 million tons of material; this can penetrate spacecraft walls or affect their electronics, disable satellites, and take down terrestrial electrical transformers and power grids. There are currently about 1800 active satellites circling our planet, and our dependence on space technology is only growing stronger.

Aurora over Norway

“This highlights a pressing need for more accurate space weather forecasts,” says Philippe Escoubet, Project Scientist for ESA’s Cluster mission.

“To understand and predict this weather, we need to know more about how the Earth and the Sun are connected, and what the magnetic environment around the Earth looks and acts like. This is what Cluster is helping us to do.”

Various spacecraft are investigating the magnetic environment around the Earth and how it interacts with the solar wind. Efforts have been internationally collaborative, from observatories including ESA’s Cluster and Swarm missions, NASA’s Magnetospheric MultiScale mission (MMS), the Van Allen Probes, and THEMIS (Time History of Events and Macroscale Interactions during Substorms), and the Japanese (JAXA/ISAS) Arase and Geotail missions.

The science of space weather

Cluster comprises four identical spacecraft that fly in a pyramid-like formation, and is able to gather incredibly detailed data on the complex structure and fluctuations of our magnetic environment.

For nearly two decades, this quartet has mapped our magnetosphere and pinpointed flows of cold plasma and interactions with the solar wind, probed our magnetotail – an extension of the magnetosphere that stretches beyond the Earth in the direction opposite to the Sun. The mission also modelled the small-scale turbulence and intricate dynamics of the solar wind itself, and helped to explain the mysteries of Earth’s auroras.

While this back catalogue of discoveries is impressive enough, Cluster is still producing new insights, especially in the realm of space weather. Recently, the mission has been instrumental in building more accurate models of our planet’s magnetic field both close to Earth (at so-called geosynchronous altitudes) and at large distances from Earth’s surface – no mean feat.

These recent models were based on data from Cluster and other missions mentioned above, and put together by scientists including Nikolai Tsyganenko and Varvara Andreeva of Saint-Petersburg State University, Russia. They provide a way to trace magnetic field lines and determine how they evolve and change during storms, and can thus create a magnetic map of all the satellites currently in orbit around the Earth down to low altitudes.

In addition, ESA's Swarm mission is also providing insight into our planet’smagnetic field. Launched in 2013 and comprising three identical satellites, Swarm has been measuringpreciselythe magnetic signals that stem from Earth’s core, mantle, crust and oceans, as well as from the ionosphere and magnetosphere.

“This kind of research is invaluable,” adds Escoubet. “Unexpected or extreme outbursts of space weather can badly damage any satellites we have in orbit around the Earth, so being able to keep better track of them – while simultaneously gaining a better understanding of our planet’s dynamic magnetic field structure – is key to their safety.”

Cluster also recently tracked the impact of huge outbursts of highly energetic particles and photons from the outer layers of the Sun known as coronal mass ejections (CMEs). The data showed that CMEs are able to trigger both strong and weak geomagnetic storms as they meet and are deformed at Earth’s bow shock – the boundary where the solar wind meets the outer limits of our magnetosphere.

Coronal mass ejection

Such storms are extreme events. Cluster explored a specific storm that occurred in September 2017, triggered by two consecutive CMEs separated by 24 hours. It studied how the storm affected the flow of charged particles leaving the polar regions of the ionosphere, a layer of Earth's upper atmosphere, above around 100 km, and found this flow to have increased around the polar cap by more than 30 times. This enhanced flow has consequences for space weather, such as increased drag for satellites, and is thought to be a result of the ionosphere being heated by multiple intense solar flares.

The mission has observed how various other phenomena affect our magnetosphere, too. It spotted tiny, hot, local anomalies in the flow of solar wind that caused the entire magnetosphere to vibrate, and watched the magnetosphere growing and shrinking significantly in size back in 2013, interacting with the radiation beltsthat encircle our planet as it did so. 

Importantly, it also measured the speed of the solar wind at the ‘nose’ of the bow shock. These observations connect data gathered near Earth to those obtained by Sun-watching satellites some 1.5 million km away at a location known as Lagrangian Point 1 – such as the ESA/NASA Solar and Heliospheric Observatory (SOHO) and NASA’s Advanced Composition Explorer (ACE). These data offer all-important evidence for solar wind dynamics in this complex and unclear region of space.

“All of this, and more, has really made it possible to better understand the dynamics of Earth’s magnetic field, and how it relates to the space weather we see,” says Escoubet.

“Cluster has produced such wonderful science in the past 18 years – but there’s still so much more to come.”

Notes for editors:

This article uses information from “Data-based modeling of the geomagnetosphere with an IMF-dependent magnetopause” by N.A. Tsyganenko (2014); “Empirical modeling of the quiet and storm time geosynchronous magnetic field” by V.A. Andreeva & N.A. Tsyganenko (2018); “Statistical study of the alteration of the magnetic structure of magnetic clouds in the Earth's magnetosheath” by L. Turc et al (2017); “O+ escape during the extreme space weather event of 4–10 September 2017” by A. Schillings et al (2018); “A statistical study on hot flow anomaly current sheets” by L.L. Zhao et al (2017); “Earth’s magnetosphere and outer radiation belt under sub-Alfvénic solar wind” by N. Lugaz et al (2016); “A statistical comparison of solar wind propagation delays derived from multi spacecraft techniques” by N.A. Case & J.A. Wild (2012)

Related article:

ESA rocks space weather:

Related links:

Space weather:

ESA’s Cluster:

ESA's Swarm:

ESA/NASA Solar and Heliospheric Observatory (SOHO):

Catalogue of discoveries:

Space weather and its hazards:

Space Weather Segment:

Monitoring space weather:

Images, Video, Text, Credits: ESA/Philippe Escoubet/Markus Bauer/S. Mazrouei/CC BY-SA 3.0 IGO.


Aboard the First Spacecraft to the Trojan Asteroids: NASA Ralph's Next Adventure

NASA - LUCY Mission patch.

Nov. 8, 2018

Ralph, one of NASA’s most well-traveled space explorers, has voyaged far and accomplished much: on the New Horizons mission, Ralph obtained stunning flyby images of Jupiter and its moons; this was followed by a visit to Pluto where Ralph took the first high-definition pictures of the iconic minor planet. And, in 2021, Ralph journeys with the Lucy mission to Jupiter’s Trojan asteroids.

Ralph, however, is not an impossibly accomplished astronaut — it is a scientific instrument that has made many discoveries since it first launched aboard the New Horizons spacecraft in 2006. Given a name and not an acronym, Ralph enables the study of the composition and atmospheres of celestial objects.

New Horizon’s Ralph — which was the first mission to visit Pluto and its moons — will fly by another Kuiper Belt object called 2014 MU69 (nicknamed Ultima Thule) in January 2019. Ralph’s observations of 2014 MU69 will provide unique insights into this small, icy world.

Illustration of Lucy. Image Credit: SwRI

The Lucy spacecraft carries a near-twin of Ralph, called L’Ralph (“Lucy Ralph”). This instrument will investigate Jupiter’s Trojan asteroids, which are remnants from the early days of the solar system. The L’Ralph instrument suite will study this diverse group of bodies; Lucy will fly by six Trojans and one Main Belt asteroid — more than any other previous asteroid mission. L’Ralph will detect the Trojan asteroids’ chemical fingerprints.

The Lucy mission payload will investigate the Trojans using: the Long Range Reconnaissance Imager (L’LORRI), the Thermal Emission Spectrometer (L’TES), and L’Ralph. L’LORRI will take high-definition photos of the Trojans, and L’TES will analyze the heat given off of the Trojans’ surface structures. L’Ralph, meanwhile, allows scientists to interpret data provided by the Sun’s reflected light that are the fingerprints of different elements and compounds. These data could provide clues about how organic molecules form in primitive bodies, a process that might also have led to the emergence of life on Earth.

L’Ralph’s instrument suite contains the Multi-spectral Visible Imaging Camera (MVIC) and the Linear Etalon Imaging Spectral Array (LEISA), both of which are fed by the same optics, meaning that Ralph can observe both visible and infrared wavelengths. These dual capabilities are what makes Ralph and its cousin L’Ralph so special, according to Dennis Reuter, the instrument principal investigator for L’Ralph. “Most instruments can image visible or infrared wavelengths, but L’Ralph can do both,” said Reuter. “We fit everything into this one small package.” At NASA’s Goddard Space Flight Center in Greenbelt, Maryland, Reuter is also the instrument scientist for Ralph on New Horizons.

L’Ralph needs to have many capabilities in a small, light body structure to keep the spacecraft efficient and the mission productive. “The key to instrument design for spacecraft is that you want to keep everything as simple as you can possibly keep it,” said Lucy Project Scientist Keith Noll, who is also located at Goddard. “L’Ralph splits light as a function of wavelength: shorter wavelengths of visible light are sent in one direction and the infrared light goes in another direction. You build a picture as the spacecraft flies along.”

Infrared telescopes are vital for modern astronomy: infrared radiation, though at wavelengths too long for the human eye to see, can be sensed by humans as heat. But breaking this infrared radiation into its constituent “colors,” a process called spectroscopy, is where the infrared instruments like L’Ralph LEISA become necessary. In conjunction with L’Ralph MVIC’s multi-color mapping ability, L’Ralph LEISA will allow scientists to detect the presence of surface compounds including ices and minerals made from various compounds and, particularly, organic materials.

If the L’Ralph instrument suite finds these substances, it will provide key information on the material that replenished the Earth’s atmospheres and oceans, after its hot and violent beginnings.

In comparison to the Ralph that flies with New Horizons, Lucy’s L’Ralph has enhanced technology. It can detect a broader spectrum of electromagnetic radiation, it has a moving mirror that reflects light into L’Ralph instead of requiring movements of the entire spacecraft, and Ralph’s infrared detectors are 2,000 pixels square, compared to New Horizons Ralph’s 256 by 256, allowing for images with more detail.

 Conceptual image of the Lucy mission to the Trojan asteroids. Image Credits: NASA/SwRI

Originally paired with the ultraviolet spectrometer Alice, Ralph was named for Ralph Kramden of the television show “The Honeymooners,” a character whose wife was named Alice. “Since L’Ralph is using the same concept as the Ralph on New Horizons, when we did the proposal, we wanted to connect them,” Reuter said. Ralph’s lineage was born.

As one Ralph advances deeper into the Kuiper Belt and another prepares for its voyage to the Trojan Asteroids, both instruments are tasked with examining some of the oldest bodies in our solar system. Each second of flyby brings us many steps closer to answering an ancient question: how did we get here? Perhaps L’Ralph will help us find this long-awaited answer.

The Lucy mission is led by Principal Investigator Dr. Hal Levison, a program director at Southwest Research Institute’s branch in Boulder, Colorado. Goddard is building much of L’Ralph, including its telescope assembly and LEISA. SwRI’s headquarters in San Antonio is packaging MVIC. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will provide overall mission management, systems engineering, and safety and mission assurance. Lockheed Martin will assemble all of the instruments and put them on the spacecraft, which will undergo further testing before Lucy and L’Ralph will be among the planets.

Related article:

Cosmic Detective Work: Why We Care About Space Rocks:

For more information about NASA's Lucy mission, visit:

Images (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Tamsyn Brann.


mercredi 7 novembre 2018

Astronauts Release Japanese Spaceship

JAXA - H-II Transfer Vehicle HTV-7 patch.

November 7, 2018

Expedition 57 Commander Alexander Gerst of ESA (European Space Agency), with back-up support from NASA astronaut Serena Auñón-Chancellor, used the International Space Station’s Canadarm2 robotic arm to release a Japanese cargo spacecraft at 11:51 a.m. EST. At the time of release, the space station was flying 254 miles over the northern Pacific Ocean. Earlier, ground controllers used the robotic arm to unberth the cargo craft.

Image above: Japan’s H-II Transfer Vehicle-7 (HTV-7) is pictured moments after it was released from the grips of the Canadarm2 robotic arm. Image Credit: NASA.

After release, a new, small reentry capsule will be deployed from the unpiloted H-II Transfer Vehicle-7 (HTV-7) of the Japan Aerospace Exploration Agency (JAXA). Designed by JAXA and assembled by the station crew, the conically shaped capsule measures 2 feet in height and 2.7 feet in width. The project is a technology demonstration designed to test JAXA’s ability to return small payloads from the station for expedited delivery to researchers.

HTV-7 departs the International Space Station

HTV-7 will be a safe distance away from the space station after the last of several deorbit maneuvers. The return capsule will be ejected from a hatchway after the deorbit burn. The experimental capsule will perform a parachute-assisted splashdown off the coast of Japan, where a JAXA ship will be standing by for its recovery.

The HTV-7 spacecraft is scheduled to re-enter the Earth’s atmosphere and burn up harmlessly over the South Pacific Ocean Nov. 10.

Related links:

Expedition 57:

Space Station Research and Technology:

International Space Station (ISS):

Image (mentioned), Video, Text, Credits: NASA/Mark Garcia/NASA TV/SciNews.

Best regards,

Cosmic Detective Work: Why We Care About Space Rocks

NASA logo.

Nov. 7, 2018

Animation above: The small worlds of our solar system help us trace its history and evolution, including comets. This video clip was compiled from images taken by NASA's EPOXI mission spacecraft during its flyby of comet Hartley 2 on Nov. 4, 2010. Animation Credits: NASA/JPL-Caltech/UMD.

The entire history of human existence is a tiny blip in our solar system's 4.5-billion-year history. No one was around to see planets forming and undergoing dramatic changes before settling in their present configuration. In order to understand what came before us -- before life on Earth and before Earth itself -- scientists need to hunt for clues to that mysterious distant past.

Those clues come in the form of asteroids, comets and other small objects. Like detectives sifting through forensic evidence, scientists carefully examine these small bodies for insights about our origins. They tell of a time when countless meteors and asteroids rained down on the planets, burned up in the Sun, shot out beyond the orbit of Neptune or collided with one another and shattered into smaller bodies. From distant, icy comets to the asteroid that ended the reign of the dinosaurs, each space rock contains clues to epic events that shaped the solar system as we know it today -- including life on Earth.

NASA's missions to study these "non-planets" help us understand how planets including Earth formed, locate hazards from incoming objects and think about the future of exploration. They have played key roles in our solar system's history, and reflect how it continues to change today.

"They might not have giant volcanoes, global oceans or dust storms, but small worlds could answer big questions we have about the origins of our solar system," said Lori Glaze, acting director for the Planetary Science Division at NASA Headquarters in Washington.

NASA has a long history of exploring small bodies, beginning with Galileo's 1991 flyby of asteroid Gaspra. The first spacecraft to orbit an asteroid, Near Earth Asteroid Rendezvous (NEAR) Shoemaker, also successfully landed on asteroid Eros in 2000 and took measurements that originally hadn't been planned. The Deep Impact mission drove a probe into Comet Tempel 1 in 2005 and prompted scientists to rethink where comets formed. More recent efforts have built on those successes and will continue to teach us more about our solar system. Here's an overview of what we can learn:

Image above: This representation of Ceres' Occator Crater in false colors shows differences in the surface composition. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

Building Blocks of Planets

Our solar system as we know it today formed from grains of dust -- tiny particles of rock, metal and ice -- swirling in a disk around our infant Sun. Most of the material from this disk fell into the newborn star, but some bits avoided that fate and stuck together, growing into asteroids, comets and even planets. Lots of leftovers from that process have survived to this day. The growth of planets from smaller objects is one piece of our history that asteroids and comets can help us investigate.

"Asteroids, comets and other small bodies hold material from the solar system's birth. If we want to know where we come from, we must study these objects," Glaze said.

Two ancient fossils providing clues to this story are Vesta and Ceres, the largest bodies in the asteroid belt between Mars and Jupiter. NASA's Dawn spacecraft, which recently ended its mission, orbited both of them and showed definitively that they are not part of the regular "asteroid club." While many asteroids are loose collections of rubble, the interiors of Vesta and Ceres are layered, with the densest material at their cores. (In scientific terms, their interiors are said to be "differentiated.") This indicates both of these bodies were on their way to becoming planets, but their growth was stunted -- they never had enough material to get as big as the major planets.

But while Vesta is largely dry, Ceres is wet. It may have as much as 25 percent water, mostly bound up in minerals or ice, with the possibility of underground liquid. The presence of ammonia at Ceres is also interesting, because it typically requires cooler temperatures than Ceres' current location. This indicates the dwarf planet could have formed beyond Jupiter and migrated in, or at least incorporated materials that originated farther from the Sun. The mystery of Ceres' origins shows how complex planetary formation can be, and it underscores the complicated history of our solar system.

Image above: This artist's concept depicts the spacecraft of NASA's Psyche mission near the mission's target, the metal asteroid Psyche. Image Credits: NASA/JPL-Caltech/Arizona State Univ./Space Systems Loral/Peter Rubin.

Although we can indirectly study the deep interiors of the planets for clues about their origins, as NASA's InSight mission will do on Mars, it's impossible to drill down into the core of any sizeable object in space, including Earth. Nevertheless, a rare object called Psyche may offer the opportunity to explore a planet-like body's core without any digging. Asteroid Psyche appears to be the exposed iron-nickel core of a protoplanet -- a small world that formed early in our solar system's history but never reached planetary size. Like Vesta and Ceres, Psyche saw its path to planethood disrupted. NASA's Psyche mission, launching in 2022, will help tell the story of planet formation by studying this metal object in detail.

Image above: Artist's impression of NASA’s New Horizons spacecraft encountering 2014 MU69, a Kuiper Belt object that orbits the Sun 1 billion miles (1.6 billion kilometers) beyond Pluto, on Jan. 1, 2019. Image Credits: NASA/JHUAPL/SwRI.

Farther afield, NASA's New Horizons spacecraft is currently on its way to a distant object called 2014 MU69, nicknamed "Ultima Thule" by the mission. One billion miles farther from the Sun than Pluto, MU69 is a resident of the Kuiper Belt, a region of ice-rich objects beyond the orbit of Neptune. Objects like MU69 may represent the most primitive, or unaltered, material that remains in the solar system. While the planets orbit in ellipses around the Sun, MU69 and many other Kuiper Belt objects have very circular orbits, suggesting they have not moved from their original paths in 4.5 billion years. These objects may represent the building blocks of Pluto and other distant icy worlds like it. New Horizons will make its closest approach to MU69 on Jan. 1, 2019 -- the farthest planetary flyby in history.

"Ultima Thule is incredibly scientifically valuable for understanding the origin of our solar system and its planets," said Alan Stern, principal investigator of New Horizons, based at Southwest Research Institute in Boulder, Colorado. "It's ancient and pristine, and not like anything we've seen before."

Delivery of the Elements of Life

Small worlds are also likely responsible for seeding Earth with the ingredients for life. Studying how much water they have is evidence for how they helped seed life on Earth.

"Small bodies are the game changers. They participate in the slow and steady evolution of our solar system over time, and influence planetary atmospheres and opportunities for life. Earth is part of that story," said NASA's chief scientist Jim Green.

Image above: This "super-resolution” view of asteroid Bennu was created using eight images obtained by NASA’s OSIRIS-REx spacecraft on Oct. 29, 2018, from a distance of about 205 miles (330 kilometers). Image Credits: NASA/Goddard/University of Arizona.

One example of an asteroid containing the building blocks of life is Bennu, the target of NASA's OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mission. Bennu may be loaded with molecules of carbon and water, both of which are necessary for life as we know it. As Earth formed, and afterward, objects like Bennu rained down and delivered these materials to our planet. These objects did not have oceans themselves, but rather water molecules bound up in minerals. Up to 80 percent of Earth's water is thought to have come from small bodies like Bennu. By studying Bennu, we can better understand the kinds of objects that allowed a barren young Earth to blossom with life.

Bennu likely originated in the main asteroid belt between Mars and Jupiter, and it's thought to have survived a catastrophic collision that happened between 800 million and 2 billion years ago. Scientists think a big, carbon-rich asteroid shattered into thousands of pieces, and Bennu is one of the remnants. Rather than a solid object, Bennu is thought to be a "rubble pile" asteroid -- a loose collection of rocks stuck together through gravity and another force scientists call "cohesion." OSIRIS-REx, which will arrive at Bennu in early December 2018, after a 1.2-billion-mile (2-billion-kilometer) journey, and will bring back a sample of this intriguing object to Earth in a sample-return capsule in 2023.

The Japanese Hayabusa-2 mission is also looking at an asteroid from the same family of bodies thought to have delivered ingredients for life to Earth. Currently in orbit at asteroid Ryugu, with small hopping rovers on the surface, the mission will collect samples and return them in a capsule to Earth for analysis by the end of 2020. We will learn a lot comparing Bennu and Ryugu, and understanding the similarities and differences between their samples.

Tracers of Solar System Evolution

Most of the material that formed our solar system, including Earth, didn't live to tell the tale. It fell into the Sun or was ejected beyond the reaches of our most powerful telescopes; only a small fraction formed the planets. But there are some renegade remnants of the early days when the stuff of planets swirled with an uncertain fate around the Sun.

A particularly catastrophic time for the solar system was between 50 and 500 million years after the Sun formed. Jupiter and Saturn, our system's most massive giants, reorganized the objects around them as their gravity interacted with smaller worlds such as asteroids. Uranus and Neptune may have originated closer to the Sun and been kicked outward as Jupiter and Saturn moved around. Saturn, in fact, may have prevented Jupiter from "eating" some of the terrestrial planets, including Earth, as its gravity counteracted Jupiter's further movement toward the Sun.

Image above: Conceptual image of the Lucy mission to the Trojan asteroids. Image Credits: NASA/SwRI.

Swarms of asteroids called the Trojans could help sort out the details of that turbulent period. The Trojans comprise two clusters of small bodies that share Jupiter's orbit around the Sun, with one group ahead of Jupiter and one trailing behind. But some Trojans seem to be made of different materials than others, as indicated by their varying colors. Some are much redder than others and may have originated beyond the orbit of Neptune, while the grayer ones may have formed much closer to the Sun. The leading theory is that as Jupiter moved around long ago, these objects were corralled into Lagrange points -- places where the gravity of Jupiter and the Sun create holding areas where asteroids can be captured. The Trojans' diversity, scientists say, reflects Jupiter's journey to its present location. "They're the remnants of what was going on the last time Jupiter moved," said Hal Levison, researcher at Southwest Research Institute.

NASA's Lucy mission, launching in October 2021, will send a spacecraft to the Trojans for the first time, thoroughly investigating six Trojans (three asteroids in each swarm). For Levison, the mission's principal investigator, the spacecraft will test ideas he and colleagues have been working on for decades about Jupiter's reshaping of the solar system. "What would really be interesting is what we don't expect," he said.

Processes in an Evolving Solar System

After sundown, under the right conditions, you may notice scattered sunlight in the ecliptic plane, the region of the sky where the planets orbit. This is because sunlight is being scattered by dust left over from the collisions of small bodies such as comets and asteroids. Scientists call this phenomenon "zodiacal light," and it's an indication that our solar system is still active. Zodiacal dust around other stars indicates that they, too, may harbor active planetary systems.

Dust from small bodies has had an important role in our planet in particular. About 100 tons of meteoritic material and dust material fall on Earth every day. Some of it comes from comets, whose activity has direct implications for Earth's evolution. As comets approach the Sun and experience its heat, gases inside the comet bubble up and carry away dusty material from the comet -- including ingredients for life. NASA's Stardust spacecraft flew by Comet 81P/Wild and found that cometary dust contains amino acids, which are building blocks of life.

Image above: This view shows Comet 67P/Churyumov-Gerasimenko as seen by the OSIRIS wide-angle camera on ESA's Rosetta spacecraft on September 29, 2016, when Rosetta was at an altitude of 14 miles (23 kilometers). Image Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.

Occasional outbursts of gas and dust observed in comets indicate activity on or near their surfaces, such as landslides. The European Space Agency's Rosetta mission, which completed its exploration of Comet 67P/Churyumov-Gerasimenko in 2016, delivered unprecedented insights about cometary activity. Among the changes in the comet, the spacecraft observed a massive cliff collapse, a large crack get bigger and a boulder move. "We discovered that boulders the size of a large truck could be moved across the comet's surface a distance as long as one-and-a-half football fields," Ramy El-Maarry, a member of the U.S. Rosetta science team from the University of Colorado, Boulder, said in 2017.

Comets also influence planetary motion today. As Jupiter continues to fling comets outward, it moves inward ever so slightly because of the gravitational dance with the icy bodies. Neptune, meanwhile, throws comets inward and in turn gets a tiny outward push. Uranus and Saturn are also moving outward very slowly in this process.

"Right now we're talking about teeny amounts of motions because there's not a lot of mass left," Levison said.

Fun fact: The spacecraft that has seen the most comets is NASA's Solar & Heliospheric Observatory (SOHO), most famous for its study of the Sun. SOHO has seen the Sun "eat" thousands of comets, which means that these small worlds were spraying material in the inner part of the solar system on their journey to become the Sun's dinner.

Image above: This animation portrays a comet as it approaches the inner solar system. Light from the Sun warms the comet’s core, or nucleus, an object so small it cannot be seen at this scale. Image Credits: NASA/JPL-Caltech.

Hazards to Earth

Asteroids can still pose an impact hazard to the planets, including our own.

While the Trojans are stuck being Jupiter groupies, Bennu, the target of the OSIRIS-REx mission, is one of the most potentially hazardous asteroids to Earth that is currently known, even though its odds of colliding with Earth are still relatively small; scientists estimate Bennu has a 1‐in‐2,700 chance of impacting our planet during one of its close approaches to Earth in the late 22nd century. Right now, scientists can predict Bennu's path quite precisely through the year 2135, when the asteroid will make one of its close passes by Earth. Close observations by OSIRIS-REx will get an even tighter handle on Bennu's journey, and help scientists working on safeguarding our planet against hazardous asteroids to better understand what it would take to deflect one on an impact trajectory.

"We're developing a lot of technologies for operating with precision around these kinds of bodies, and targeting locations on their surfaces, as well as characterizing their overall physical and chemical properties. You would need this information if you wanted to design an asteroid deflection mission," said Dante Lauretta, principal investigator for the OSIRIS-REx mission, based at the University of Arizona in Tucson.

Dart Moon Collision

Video above: This animation shows how NASA’s Double Asteroid Redirection Test (DART) would target and strike the smaller (left) element of the binary asteroid Didymos to demonstrate how a kinetic impact could potentially redirect an asteroid as part of the agency’s planetary defense program. Animation Credits: NASA/JHUAPL.

Another upcoming mission that will test a technique for defending the planet from naturally occurring impact hazards is NASA's Double Asteroid Redirection Test (DART) mission, which will attempt to change a small asteroid's motion. How? Kinetic impact -- in other words, collide something with it, but in a more precise and controlled way than nature does it.

DART's target is Didymos, a binary asteroid composed of two objects orbiting each other. The larger body is about half a mile (800 meters) across, with a small moonlet that is less than one-tenth of a mile (150 meters) wide. An asteroid this size could result in widespread regional damage if one were to impact Earth. DART will deliberately crash itself into the moonlet to slightly change the small object's orbital speed. Telescopes on Earth will then measure this change in speed by observing the new period of time it takes the moonlet to complete an orbit around the main body, which is expected to be a change of less than a fraction of one percent. But even that small of change could be enough to make a predicted impactor miss Earth in some future impact scenario. The spacecraft, being built by the Johns Hopkins University Applied Physics Laboratory, is scheduled for launch in spring-summer 2021.

Didymos and Bennu are just two of the almost 19,000 known near-Earth asteroids. There are over 8,300 known near-Earth asteroids the size of the moonlet of Didymos and larger, but scientists estimate that about 25,000 asteroids in that size range exist in near-Earth space. The space telescope helping scientists discover and understand these kinds of objects, including potential hazards, is called NEOWISE (which stands for Near-Earth Object Wide-field Infrared Survey Explorer).

"For most asteroids, we know little about them except for their orbit and how bright they look. With NEOWISE, we can use the heat emitted from the objects to give us a better assessment of their sizes," said Amy Mainzer, principal investigator of NEOWISE, based at NASA's Jet Propulsion Laboratory. "That's important because asteroid impacts can pack quite a punch, and the amount of energy depends strongly on the size of the object."

Image above: This artist's concept shows the Wide-field Infrared Survey Explorer, or WISE, spacecraft, in its orbit around Earth. In its NEOWISE mission it finds and characterizes asteroids. Image Credits: NASA/JPL-Caltech.

Small Worlds as Pit Stops, Resources for Future Exploration

There are no gas stations in space yet, but scientists and engineers are already starting to think about how asteroids could one day serve as refueling stations for spacecraft on the way to farther-flung destinations. These small worlds might also help astronauts restock their supplies. For example, Bennu likely has water bound in clay minerals, which could perhaps one day be harvested for hydrating thirsty space travelers.

"In addition to science, the future will indeed be mining," Green said. "The materials in space will be used in space for further exploration."

How did metals get on asteroids? As they formed, asteroids and other small worlds collected heavy elements forged billions of years ago. Iron and nickel found in asteroids were produced by previous generations of stars and incorporated in the formation of our solar system.

These small bodies also contain heavier metals forged in stellar explosions called supernovae. The violent death of a star, which can lead to the creation of a black hole, spreads elements heavier than hydrogen and helium throughout the universe. These include metals like gold, silver and platinum, as well as oxygen, carbon and other elements we need for survival. Another kind of cataclysm -- the collision of supernova remnants called neutron stars -- can also create and spread heavy metals. In this way small bodies are also forensic evidence of the explosions or collisions of long-dead stars.

Because of big things, we now have a lot of very small things. And from small things, we get big clues about our past -- and possibly resources for our future. Exploring these objects is important, even if they aren't planets.

They are small worlds, after all.

Related links:

Near Earth Asteroid Rendezvous (NEAR):

Deep Impact mission:

NASA's Dawn:

NASA's InSight:

NASA's Psyche:

NASA's New Horizons:


NASA's Lucy:

NASA's Double Asteroid Redirection Test (DART):


ESA's  Rosetta:

JAXA's Hayabusa-2:

Images (mentioned), Animation (mentioned), Video (mentioned), Text, Credits: NASA/Tony Greicius/Elizabeth Landau.