After Two Long Careers, QuikSCAT Rings Down the Curtain

NASA - SeaWinds scatterometer QuikSCAT Mission patch.

October 13, 2018

Launched in June 1999 for an intended two-year mission, NASA's SeaWinds scatterometer instrument on the QuikSCAT spacecraft was turned off on Oct. 2 in accordance with its end-of-mission plan. QuikSCAT spent its first decade creating an unprecedented record of the speed and direction of winds at the ocean surface. Then, for another nine years, it served as the gold standard of accuracy against which new spaceborne scatterometers were calibrated.

Image above: QuikSCAT imaged winds during many storms, including Hurricane Katrina, shown here covering the Gulf of Mexico in August 2005. Highest wind speeds appear purple, with winds weakening outward from the eye. Barbs show wind direction; white barbs indicate heavy rainfall. Image Credits: NASA/JPL-Caltech.

Managed by NASA's Jet Propulsion Laboratory in Pasadena, California, QuikSCAT was a unique national resource that far surpassed NASA's original science objective for the mission. During its 10 years of observing winds over the global ocean surface, QuikSCAT measurements were used by the world's weather forecasting agencies to improve forecasts and identify and monitor hurricanes and other storms far out in the open seas. Its data also provided critical information for monitoring, researching, modeling, and forecasting the atmosphere, ocean, ice and climate.

Among its many accomplishments:

• QuikSCAT discovered that hurricane-strength winds occur frequently in the North Atlantic and North Pacific oceans, where such strong winds were not previously expected to exist.

• It provided high-resolution observations of the dramatically accelerating changes in sea ice cover on the Arctic Ocean.

• The mission's measurements were used widely beyond weather forecasting and research -- for example, to help identify efficient shipping routes, plan new offshore wind farms, and guide search-and-rescue operations at sea.

Michael Freilich, the QuikSCAT mission's original principal investigator and now director of NASA's Earth Science Division, noted, "QuikSCAT operated in space for nearly two decades, and we are certain that its impact and legacy will last much longer."

Ernesto Rodríguez, QuikSCAT project scientist at JPL, said, "The decommissioning of QuikSCAT marks the passing of an era. Many scientists and forecasters have built their careers over the last 20 years using QuikSCAT. Its data led to major discoveries on the interaction between the ocean and the atmosphere."

A few months after QuikSCAT's 10th anniversary, an age-related problem caused its spinning antenna to stop rotating, reducing its observing swath to only 19 miles (30 kilometers) wide. The extreme accuracy of this narrow swath measurement, however, allowed QuikSCAT to take on a second mission: calibrating newer satellites to enable a much longer data record of ocean winds.

SeaWinds scatterometer QuikSCAT spacecraft. Image Credits: NASA/JPL

Satellite instruments are regularly calibrated to ensure their readings match other data that are known to be accurate, and to correct for an instrument's normal drift in accuracy over time. QuikSCAT's exceptional stability made it invaluable in assuring that newer missions from the Indian and European space agencies and from NASA are providing apples-to-apples measurements. This function proved so important to the research community that QuikSCAT's decommissioning was postponed twice to allow time for new scatterometers to be launched and calibrated.

QuikSCAT project manager Rob Gaston of JPL said, "It's a testament to the research community's commitment to climate research that QuikSCAT's intercalibration mission has continued to receive the highest possible marks for science relevance in the reviews that NASA follows to establish funding priorities for missions like QuikSCAT. The intercalibration mission has enabled research that would not have been possible but for the remarkable stability of the SeaWinds instrument and the exceptional reliability and longevity of the QuikSCAT spacecraft."

QuikSCAT was originally a recovery mission after the loss of Japan's Advanced Earth Observing Satellite, which hosted the NASA Scatterometer (NSCAT). The QuikSCAT mission was conceived, developed and launched in less than two years. Ball Aerospace & Technologies Corp. in Boulder, Colorado, built the spacecraft bus, and JPL designed and built the SeaWinds instrument. QuikSCAT was operated by the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.

NASA & JPL QuikSCAT: https://winds.jpl.nasa.gov/missions/quikscat/

ESA QuikSCAT: https://earth.esa.int/web/eoportal/satellite-missions/q/quikscat

Images (mentioned), Text, Credits: NASA/JPL/Esprit Smith/NASA's Earth Science News Team, written by Carol Rasmussen.

Greetings, Orbiter.ch

Station Crew Busy With Science After Aborted Launch Ascent

ISS - Expedition 57 Mission patch.

October 12, 2018

Three Expedition 57 crew members are staying busy aboard the International Space Station after the climb to orbit of two crewmates was aborted Thursday morning. American Nick Hague and Russian Alexey Ovchinin made an emergency landing shortly after launch, but are in excellent shape and back in Russia. The trio in orbit is continuing science and maintenance aboard the orbital laboratory.

Image above: North Africa and the Mediterranean Sea are pictured as the International Space Station orbited 254 miles above the African continent. Japan’s Kounotori H-II Transfer Vehicle-7 (HTV-7) is pictured at left attached to the Harmony module. Image Credit: NASA.

NASA astronaut Hague and Roscosmos cosmonaut Ovchinin are safe and returned to Moscow with mission officials after their aborted mission. The Soyuz MS-10 rocket booster experienced a failure about two minutes after launching from the Baikonur Cosmodrome in Kazakhstan. Hague will return to Houston, Texas, on Saturday and Ovchinin will stay in Moscow. Investigations into the cause of the failure are beginning, and the space station international partner agencies are evaluating what changes to the station’s operating plan will need to be adopted.

The three humans still orbiting Earth are safe with plenty of supplies and work to do on orbit. Commander Alexander Gerst and Flight Engineer Serena Auñón-Chancellor started their day measuring how microgravity has impacted their muscles for the Myotones study. They then moved on to researching an ancient technique that may be used for emergency navigation on future space missions.

Serena Auñón-Chancellor is scheduled to talk with two different school groups on Monday and Thursday next week. One of those conversations will involve the flight of Seaman Jr., a plush toy that is part of the National Park Service’s celebration of its the 3,700 mile Lewis and Clark National Historic Trail.

Image above: Flying on the line of the Terrestrial Ecuador, Pacific Ocean, seen by EarthCam on ISS, speed: 27'607 Km/h, altitude: 408,06 Km, image captured by Roland Berga (on Earth in Switzerland) from International Space Station (ISS) using ISS-HD Live application with EarthCam's from ISS on October 12, 2018 at 18:18 UTC. Image Credits: Orbiter.ch Aerospace/Roland Berga.

Flight Engineer Sergey Prokopyev maintained life support systems in the Russian segment of the space station. He also updated the station’s inventory system and checked on Russian science experiments.

Related links:

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

Myotones: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7573

Ancient technique: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7646

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

Update on the Hubble Space Telescope Safe Mode

NASA - Hubble Space Telescope patch.

Oct. 12, 2018

NASA continues to work toward resuming science operations of the Hubble Space Telescope after the spacecraft entered safe mode due to a failed gyroscope (gyro) on Friday, Oct. 5.

Following the gyro failure, the Hubble operations team turned on a backup gyro on the spacecraft. However, that gyro did not perform as expected, reporting rotation rates that are orders of magnitude higher than they actually are. This past week, tests were conducted to assess the condition of that backup gyro. The tests showed that the gyro is properly tracking Hubble’s movement, but the rates reported are consistently higher than the true rates. This is similar to a speedometer on your car continuously showing that your speed is 100 miles per hour faster than it actually is; it properly shows when your car speeds up or slows down, and by how much, but the actual speed is inaccurate.

When the spacecraft turns across the sky from one target to the next, the gyro is put into a coarser (high) mode. In this high mode it may be possible to subtract out a consistent large offset to get an accurate reading. However, after the large turns are over, the spacecraft attempts to lock onto a target and stay very still. For this activity, the gyro goes into a precision (low) mode to measure very small movements. The extremely high rates currently being reported exceed the upper limit of the gyro in this low mode, preventing the gyro from reporting the spacecraft’s small movements.

NASA's Hubble Space Telescope. Image Credit: NASA

An anomaly review board that consists of professionals experienced in the manufacturing of such gyros, Hubble operations personnel, flight software engineers and other experts was formed earlier this week to identify the cause of this behavior and determine what solutions can be implemented from the ground to correct or compensate for it.

If the team is successful in solving the problem, Hubble will return to normal, three-gyro operations. If it is not, the spacecraft will be configured for one-gyro operations, which will still provide excellent science well into the 2020s, enabling it to work alongside the James Webb Space Telescope and continue groundbreaking science.

Safe mode places the telescope into a stable configuration that suspends science observations and orients the spacecraft’s solar panels toward the Sun to ensure Hubble’s power requirements are met. The spacecraft remains in this configuration until ground control can correct or compensate for the issue. The rest of the spacecraft and its instruments are still fully functional and are expected to produce excellent science for years to come.

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

A gyro is a device that measures the speed at which the spacecraft is turning, and is needed to help Hubble turn and lock on to new targets. To meet the stringent pointing requirements necessary to study far-off astronomical objects and obtain groundbreaking science data, Hubble’s gyros are extremely accurate. Hubble preferably uses three gyros at any given time to make the observatory as efficient as possible, and would work at slightly lower efficiency on only one gyro.

During Servicing Mission 4 in 2009, astronauts installed six new gyros on Hubble. Three gyros have since failed after achieving or exceeding the average runtime for a Hubble gyro. When fewer than three operational gyros remain, Hubble will continue to make scientific observations in a previously developed and tested mode that uses just one gyro in order to maximize the observatory’s lifetime.

Originally required to last 15 years, Hubble has now been operating for more than 28. The final servicing mission in 2009, expected to extend Hubble’s lifetime an additional 5 years, has now produced more than 9 years of science observations.

Hubble is managed and operated at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Related article:

Hubble in Safe Mode as Gyro Issues are Diagnosed:
https://orbiterchspacenews.blogspot.com/2018/10/hubble-in-safe-mode-as-gyro-issues-are.html

For more information about Hubble, visit:

http://hubblesite.org/
http://www.nasa.gov/hubble
http://www.spacetelescope.org/

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Felicia Chou.

Greetings, Orbiter.ch

Practising for BepiColombo’s epic escape to Mercury

ESA - BepiColombo Mission patch.

12 October 2018

The international BepiColombo spacecraft will soon take flight, on a complex journey to the innermost planet of the Solar System, Mercury. Encompassing nine planetary flybys and travelling a total distance of nine billion km over a period of seven years, this will be one of the most intricate journeys ever flown by mission teams at ESA’s ESOC mission control centre.

BepiColombo at Mercury

With launch set for 20 October, flight controllers led by Operations Manager Elsa Montagnon are now busily preparing for the start of what will be Europe’s first mission to Mercury — the smallest and least explored terrestrial planet of the Solar System.

“Mission teams have spent months simulating BepiColombo’s unique and complex journey,” explains Elsa.

BepiColombo teams in training for voyage to Mercury

“Taking turns, in 12-hour shifts, we have been practising the spacecraft’s various launch and early mission processes and manoeuvres in real-time so we are prepared for every possible eventuality.”

BepiColombo is a joint mission between ESA and the Japan Aerospace Exploration Agency (JAXA). The mission comprises two science orbiters: ESA’s Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter (MMO).

The ESA-built Mercury Transfer Module (MTM) will carry the orbiters to Mercury using a combination of solar electric propulsion and gravity assist flybys.

BepiColombo exploded view

After its arrival at the planet of extremes in 2025, it will spend at least a year in orbit gathering data on Mercury’s composition, density, magnetic field and exosphere, as well as probing the planet’s interaction with solar wind.

Before the science begins, however, the multi-module spacecraft has to safely escape Earth, switch on, and receive instructions from mission control on where to go next.

A rocky road

Europe’s space scientists have identified BepiColombo as one of the most challenging long-term planetary projects ever flown, as Mercury’s proximity to the Sun makes it difficult for spacecraft to reach without being pulled into the star’s enormous gravity.

Animation visualising BepiColombo’s journey to Mercury

“To get to Mercury without being subsumed by our giant star, the spacecraft will make a series of nine planetary flybys; circling Earth once, Venus twice, and Mercury itself six times,” explains Andrea Accomazzo, Flight Director for BepiColombo.

“Unlike missions that take spacecraft to the outer regions of the Solar System, the Mercury Transfer Module will use the gravity of these inner planets, in combination with the thrust provided by electric propulsion, to slow the spacecraft down.”

The Sun’s huge gravity field acts as an enormous gravity ‘well’. Getting a spacecraft to Mercury, and therefore close to the Sun, means dropping it into this steep well – the difficulty comes in ensuring the spacecraft ends up at Mercury and not at our gigantic star.

“The closer we get to the Sun the more we are constricted in our path,” explains Frank Budnik from the Flight Dynamics team.

BepiColombo cruise configuration

“For example, BepiColombo’s large solar arrays need to be tilted at just the right angle to get enough sunlight to power the high-energy demand of the propulsion system and keeping the spacecraft running. At the same time, they mustn't get too much sunlight, or they could be beyond their limits.”

“There is only a small corridor in which the solar arrays can be operated to fulfil both of these constraints.”

BepiColombo will launch at 01:45 GMT (03:45 CEST) on 20 October, on board an Ariane 5 rocket. After the spacecraft separates from the rocket's 'upper stage', teams at ESOC will take control, sending commands to the spacecraft to get it into normal operational mode — a process that is expected to take about four days.

This period, dubbed the ‘Launch and Early Orbit Phase’ (LEOP), sees the control systems and instruments switched on, and their health and proper functioning assessed.

This is a risky time when the satellite is unusually vulnerable — not yet fully functional but still exposed to the hazards of space.

Simulating the scene

In preparation for this vital period, mission control teams have spent months simulating every expected scenario — the perfect LEOP, launch and separation of the satellite from the launcher, as well as a whole host of scenarios in which something goes wrong.

Establishing contact between the spacecraft and mission controllers has also been rehearsed.

Deep space ground stations across three continents will support this mission, with ESA’s global antenna network maintaining links to and from BepiColombo throughout the journey.

“BepiColombo is one of the world’s most ambitious interplanetary missions, and it could not be in safer hands,” says Rolf Densing, Director of Operations at ESOC.

“With decades of collective experience and hundreds of hours of simulation practice, teams at ESA’s mission control are ready to set out for the rocky planet.”

Go to esa.int/live to watch the launch live from 03:15 CEST: http://esa.int/live

Related link:

ESA's BepiColombo: http://sci.esa.int/bepicolombo/

Images, Video, Text, Credits: ESA/ATG medialab/CC BY-SA 3.0 IGO/NASA/JPL.

Best regards, Orbiter.ch

Chandra Enters Safe Mode; Investigation Underway

NASA - Chandra X-ray Observatory patch.

Oct. 12, 2018

At approximately 9:55 a.m. EDT on Oct. 10, 2018, NASA’s Chandra X-ray Observatory entered safe mode, in which the observatory is put into a safe configuration, critical hardware is swapped to back-up units, the spacecraft points so that the solar panels get maximum sunlight, and the mirrors point away from the Sun. Analysis of available data indicates the transition to safe mode was normal behavior for such an event. All systems functioned as expected and the scientific instruments are safe. The cause of the safe mode transition (possibly involving a gyroscope) is under investigation, and we will post more information when it becomes available.

Artist's concept of Chandra X-ray Observatory. Image Credits: NASA/CXC/SAO

Chandra is 19 years old, which is well beyond the original design lifetime of 5 years. In 2001, NASA extended its lifetime to 10 years. It is now well into its extended mission and is expected to continue carrying out forefront science for many years to come.

Chandra X-Ray Observatory: https://www.nasa.gov/mission_pages/chandra/main/index.html

Image (mentioned), Text, Credits: NASA/Brian Dunbar.

Greetings, Orbiter.ch

Update on Opportunity Rover after Martian Dust Storm

NASA - Mars Exploration Rover B (MER-B) patch.

Oct. 12, 2018

One month since increasing their commanding frequency, engineers have yet to hear from NASA's Opportunity rover.

NASA hasn't set any deadlines for the mission but will be briefed later this month on the progress and prospects for the recovery campaign being carried out at the agency's Jet Propulsion Laboratory in Pasadena, California.

JPL engineers are employing a combination of listening and commanding methods in case Opportunity is still operational. It's possible that a layer of dust deposited on the rover's solar panels by the recent global dust storm is blocking sunlight that could recharge its batteries. No one can tell just how much dust has been deposited on its panels.

Animation above: Side-by-side movies shows how dust has enveloped the Red Planet, courtesy of the Mars Color Imager (MARCI) wide-angle camera onboard NASA's Mars Reconnaissance Orbiter (MRO). Animation Credits: NASA/JPL-Caltech/MSSS.

A windy period on Mars -- known to Opportunity's team as "dust-clearing season" -- occurs in the November-to-January time frame and has helped clean the rover's panels in the past. The team remains hopeful that some dust clearing may result in hearing from the rover in this period.

Opportunity has exceeded its expected lifespan many times over. Both Opportunity and its twin, Spirit, were designed to last only 90 days on the Martian surface, with the expectation that the planet's extreme winters and dust storms could cut their mission short. The rover has lasted nearly 15 years: It last communicated on June 10 before being forced into hibernation by the growing dust storm.

Updated at 2:45 p.m. PDT on Sept. 11, 2018

Scientists reviewing data from the Mars Color Imager (MARCI) aboard NASA's Mars Reconnaissance Orbiter (MRO) have determined that the tau estimate (a measure of the amount of haze in the Martian atmosphere) in the skies above the rover Opportunity has been below 1.5 for two consecutive measurements. With more sunlight reaching the rover's solar array, the Opportunity team at NASA's Jet Propulsion Laboratory in Pasadena, California, are increasing the frequency of commands it beams to the 14-plus-year-old rover via the dishes of NASA's Deep Space Network from three times a week to multiple times per day. Passive listening for Opportunity will also continue to be performed by JPL's Radio Science Group, which records radio signals emanating from Mars with a very sensitive broadband receiver.

The original story has been updated in paragraph six to reflect NASA review at each step of the recovery process. Updates on the 2018 dust storm and tau can be found here.

A planet-encircling dust storm on Mars, which was first detected May 30 and halted operations for the Opportunity rover, continues to abate.

With clearing skies over Opportunity’s resting spot in Mars’ Perseverance Valley, engineers at NASA’s Jet Propulsion Laboratory in Pasadena, California, believe the nearly 15-year-old, solar-powered rover will soon receive enough sunlight to automatically initiate recovery procedures -- if the rover is able to do so. To prepare, the Opportunity mission team has developed a two-step plan to provide the highest probability of successfully communicating with the rover and bringing it back online.

Image above: Opportunity's panoramic camera (Pancam) took the component images for this view from a position outside Endeavor Crater during the span of June 7 to June 19, 2017. Toward the right side of this scene is a broad notch in the crest of the western rim of crater. Image Credits: NASA/JPL-Caltech/Cornell/Arizona State Univ.

“The Sun is breaking through the haze over Perseverance Valley, and soon there will be enough sunlight present that Opportunity should be able to recharge its batteries,” said John Callas, Opportunity project manager at JPL. “When the tau level [a measure of the amount of particulate matter in the Martian sky] dips below 1.5, we will begin a period of actively attempting to communicate with the rover by sending it commands via the antennas of NASA’s Deep Space Network. Assuming that we hear back from Opportunity, we will begin the process of discerning its status and bringing it back online.”

The rover’s last communication with Earth was received June 10, and Opportunity’s current health is unknown. Opportunity engineers are relying on the expertise of Mars scientists analyzing data from the Mars Color Imager (MARCI) aboard NASA’s Mars Reconnaissance Orbiter (MRO) to estimate the tau near the rover’s position.

“The dust haze produced by the Martian global dust storm of 2018 is one of the most extensive on record, but all indications are it is finally coming to a close,” said MRO Project Scientist Rich Zurek at JPL. “MARCI images of the Opportunity site have shown no active dust storms for some time within 3,000 kilometers [about 1,900 miles] of the rover site.”

With skies clearing, mission managers are hopeful the rover will attempt to call home, but they are also prepared for an extended period of silence. "If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover," said Callas. At that point, the team will report to NASA HQ to determine whether to continue with the strategy or adjust it. Callas added, "In the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun's energy, we will continue passive listening efforts for several months."

The additional several months for passive listening are an allowance for the possibility that a Red Planet dust devil could come along and literally dust off Opportunity’s solar arrays. Such “cleaning events” were first discovered by Mars rover teams in 2004 when, on several occasions, battery power levels aboard both Spirit and Opportunity increased by several percent during a single Martian night, when the logical expectation was that they would continue to decrease. These cleaning dust devils have even been imaged by both rovers on the surface and spacecraft in orbit (see https://www.youtube.com/watch?v=k8lfJ0c7WQ8 and  https://mars.nasa.gov/resources/5307/the-serpent-dust-devil-of-mars/).

The chances are small that dust accumulation would be the root cause of Opportunity’s lack of communication. Nonetheless, each day during the passive phase, JPL’s Radio Science group will scour the signal records taken by a very sensitive broadband receiver of radio frequencies emanating from Mars, looking for a sign that the rover is trying to reach out.

Mars Exploration Rover (MER): Image Credits: NASA/JPL-Caltech/AP

Even if the team hears back from Opportunity during either phase, there is no assurance the rover will be operational. The impact of this latest storm on Opportunity’s systems is unknown but could have resulted in reduced energy production, diminished battery performance, or other unforeseen damage that could make it difficult for the rover to fully return online.

While the situation in Perseverance Valley is critical, the rover team is cautiously optimistic, knowing that Opportunity has overcome significant challenges during its 14-plus years on Mars. The rover lost use of its front steering -- its left-front in June of 2017, and right front in 2005. Its 256-megabyte flash memory is no longer functioning. The team also knows that everything about the rover is well beyond its warranty period -- both Opportunity and its twin rover, Spirit, were constructed for 90-day missions (Spirit lasted 20 times longer and Opportunity is going on 60 times). The rovers were designed to travel about 1,000 yards, and Opportunity has logged more than 28 miles. Through thick and thin, the team has seen their rover soldier on. Now, Opportunity engineers and scientists of Opportunity are planning, and hoping, that this latest dilemma is just another bump in their Martian road.

“In a situation like this you hope for the best but plan for all eventualities,” said Callas. “We are pulling for our tenacious rover to pull her feet from the fire one more time. And if she does, we will be there to hear her.”

Updates on the dust storm and tau can be found here: https://mars.nasa.gov/mer/mission/status_opportunityAll.html

JPL, a division of Caltech in Pasadena, built Opportunity and manages the mission for NASA's Science Mission Directorate, Washington.

Related articles:

Martian Skies Clearing over Opportunity Rover:
https://orbiterchspacenews.blogspot.com/2018/08/martian-skies-clearing-over-opportunity.html

Six Things About Opportunity's Recovery Efforts:
https://orbiterchspacenews.blogspot.com/2018/08/six-things-about-opportunitys-recovery.html

NASA Mars Exploration Rover Status Report:
https://orbiterchspacenews.blogspot.com/2018/08/nasa-mars-exploration-rover-status.html

Shades of Martian Darkness:
https://orbiterchspacenews.blogspot.com/2018/06/shades-of-martian-darkness.html

Opportunity Hunkers Down During Dust Storm:
https://orbiterchspacenews.blogspot.com/2018/06/opportunity-hunkers-down-during-dust.html

For more information about Opportunity, visit:

https://www.nasa.gov/rovers

https://marsrovers.jpl.nasa.gov

Animation (mentioned), Images (mentioned), Text, Credits: NASA/JoAnna Wendel/Tony Greicius/JPL/DC Agle/Andrew Good.

Greetings, Orbiter.ch

NASA Celebrates the 50th Anniversary of Apollo 7

NASA - Apollo 7 Mission patch.

Oct. 11, 2018

Image above: Apollo 7 Launched as Race to Moon Reached Final Stretch. Image Credits: NASA.

On Oct. 11, 1968, NASA launched its first crewed Apollo mission, which paved the way for the moon landing less than a year later.

The Apollo 7 crew was commanded by Walter Schirra, with Command Module Pilot Donn Eisele, and Lunar Module Pilot Walter Cunningham. The mission consisted of an 11-day Earth-orbital test flight to test the Apollo command and service module. It was also the first time a crew flew on the Saturn IB rocket.

Apollo 50th: First Crew Launches on Apollo 7

Video above: Even 50 years later, Apollo 7 is still remembered as one of the most important first test flights of any spacecraft. Video Credit: NASA.

Although Apollo 7 was a complete technical success, it was born out of a tragedy. After the fatal fire that took the lives of the Apollo 1 crew—Gus Grissom, Roger Chaffee, and Ed White—the Apollo 7 crew took over the mission.

Apollo 1 was supposed to be the first crewed Apollo mission. During a launch rehearsal test at Cape Kennedy, an electrical fire broke out in the cabin. Because the cabin atmosphere was pure oxygen, the fire spread incredibly quickly. The fire also created intense pressure inside the cabin, and because the hatch could only swing inward, the crew was stuck inside.

All further crewed missions had to wait until NASA could determine the sources of the mishap—technical and organizational—and ensure that nothing like it would happen again. In the 21 months between Apollo 1 and Apollo 7, the Apollo spacecraft and spacesuits were redesigned to more safely fly crews to space. 

Image above: The Apollo 7 Prime Crew was (from left) Command Module Pilot Donn Eisele, Commander Walter Schirra and Lunar Module Pilot Walter Cunningham. Image Credit: NASA.

While Apollo 4, 5, and 6 practiced some of the maneuvers necessary to build up to a lunar landing, such as the first flight of the Saturn V rocket and high-speed reentry, none of these missions were crewed. (Apollo 2 and 3 were skipped in the sequence out of respect to the Apollo 1 crew.)

By late 1968, NASA was ready to move forward from the Apollo 1 disaster and work toward landing on the moon. The Apollo 7 crew not only had to take over the mission that their friends and colleagues had died training for, but they have to prove to the world that the Apollo program was still in good shape to continue.

“Gus would be the first person to say, ‘Let’s get on with it. Do good work,’” said Apollo 7 Commander Wally Schirra, reflecting on the mission.

Image above: Apollo 7 lifts off from Cape Kennedy (now Cape Canaveral) Air Force Station's Launch Complex 34 on Oct. 11, 1968. It was the first of several piloted flights designed to qualify the spacecraft for the half-million-mile round trip to the Moon. Image Credit: NASA.

On Oct. 11, Apollo 7 launched from Cape Kennedy Air Force Station, Florida. The Saturn IB rocket performed well and the liftoff was smooth. Aside from minor hardware problems, there were no significant problems or anomalies during the flight. The Apollo Command and Service Module passed the test and cleared the way for Apollo 8 to complete its lunar orbit, and instilled the confidence in the Apollo 11 crew to land on the moon. Apollo 7 was not only the first three-person American space mission, but it was also the first to include a live television broadcast from inside an American spacecraft.

Eleven days after the launch, the Apollo 7 crew splashed down south of Bermuda and the crew was instantly celebrated for their success.

“It was the longest, it was the most ambitious, and most successful first test flight of any new flying machine, ever,” said Apollo 7 Lunar Module Pilot Walter Cunningham. “And it’s still true today, 50 years later.”

NASA Marks the Legacy of Apollo

Image Credit: NASA

From October 2018 through December 2022, NASA is marking the 50th anniversary of the 11 piloted Apollo missions that included landing a dozen Americans on the Moon between July 1969 and December 1972. Today, NASA is working to return astronauts to the Moon to test technologies and techniques for the next giant leaps – challenging missions to Mars and other destinations in deep space.

For more information about NASA’s plan for the future, visit:

NASA Exploration: Back to the Moon and On to Mars: https://www.nasa.gov/feature/nasas-exploration-campaign-back-to-the-moon-and-on-to-mars

Related links:

Apollo 7: https://www.nasa.gov/mission_pages/apollo/apollo-7.html

NASA History: https://www.nasa.gov/topics/history/index.html

Images (mentioned), Video (mentioned), Text, Credits: NASA/Thalia Patrinos.

Best regards, Orbiter.ch

Crew in Good Condition After Booster Failure

ROSCOSMOS - Soyuz MS-10 Mission patch.

Oct. 11, 2018

Astronaut Nick Hague (left) and Roscosmos Director Dmitry Rogozin

NASA Astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin are seen in Dzhezkazgan, Kazakhstan. They are in good condition following their safe landing on Earth after a Soyuz booster failure after launch earlier.

Roscosmos cosmonaut Alexey Ovchinin

 

NASA astronaut Nick Hague

NASA Statement on Soyuz MS-10 Launch Abort

The following is a statement about Thursday’s Soyuz MS-10 launch abort to the International Space Station:

“The Soyuz MS-10 spacecraft launched from the Baikonur Cosmodrome in Kazakhstan to the International Space Station at 4:40 a.m. EDT Thursday, Oct. 11 (2:40 p.m. in Baikonur) carrying American astronaut Nick Hague and Russian cosmonaut Alexey Ovchinin. Shortly after launch, there was an anomaly with the booster and the launch ascent was aborted, resulting in a ballistic landing of the spacecraft.

Soyuz MS-10 crew safe after booster failure

Video above: The Soyuz MS-10 crew, NASA Astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin, are in good condition following their safe landing on Earth after a Soyuz booster failure, following the launch from the Baikonur Cosmodrome in Kazakhstan, on 11 October 2018, at 08:40 UTC (14:40 local time).are seen in Dzhezkazgan, Kazakhstan.

“Search and rescue teams were deployed to the landing site. Hague and Ovchinin are out of the capsule and are reported to be in good condition. They will be transported to the Gagarin Cosmonaut Training Center in Star City, Russia outside of Moscow.

Soyuz MS-10 abort explained

Video above: Kenny Todd, International Space Station Operations Integration Manager, and Reid Wiseman, Deputy Chief Astronaut, talking about the Soyuz MS-10 abort with NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin, after being launched by a Soyuz-FG rocket from the Baikonur Cosmodrome in Kazakhstan, on 11 October 2018, at 08:40 UTC (14:40 local time).

“NASA Administrator Jim Bridenstine and the NASA team are monitoring the situation carefully. NASA is working closely with Roscosmos to ensure the safe return of the crew. Safety of the crew is the utmost priority for NASA. A thorough investigation into the cause of the incident will be conducted.”

Related article:

Soyuz MS-10 - Emergency landing after a failure:
https://orbiterchspacenews.blogspot.com/2018/10/soyuz-ms-10-emergency-landing-after.html

Roscosmos Press Release: https://www.roscosmos.ru/25598/

Related links:

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images, Videos, Text, Credits: NASA/Mark Garcia/Bob Jacobs/Allard Beutel/NASA TV/Roscosmos TV/SciNews.

Greetings, Orbiter.ch

NASA’s Terra Satellite Celebrates 100,000 Orbits

NASA - EOS Terra Mission patch.

Oct. 11, 2018

More than 400 miles above Earth, a satellite the size of a school bus is earning its frequent flyer miles. On Oct. 6, NASA’s Terra completed 100,000 orbits around Earth. Terra joins a handful of satellites to mark this orbital milestone, including the International Space Station, Earth’s Radiation Budget Satellite (ERBS), Landsat 5 and Landsat 7. Terra, which launched Dec. 18, 1999, is projected to continue operation into the 2020s.

Image above: Illustration of Terra satellite in orbit of Earth. Image Credits: NASA's Goddard Space Flight Center/Chris Meaney.

The five scientific instruments aboard Terra provide long-term value for advancing scientific understanding of our planet — one of the longest running satellite climate data records — and yield immediate benefits in such areas as public health. For example, recently scientists analyzed 15 years of pollution data in California, collected by the Multi-angle Imaging Spectroradiometer (MISR) instrument, and discovered that the state’s clean air programs have been successful in reducing particle pollution. More urgently, data from the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) and MISR provided crucial information about the air quality and land change conditions around Hawaii’s erupting Kilauea volcano, informing critical public health and safety decisions.

Image above: Members of the Terra design team stand in front of a true-to-size model of the satellite in the mid-1990s. Image Credits: courtesy of Dick Quinn.

But just as a plane can’t fly without a crew, the Terra satellite never could have provided these vital benefits to society for this long without decades of dedicated work by engineers and scientists.

Completing more than 2.5 billion miles of flight around Earth over almost 19 years, by a satellite designed to operate for five years, does not happen unless a satellite is designed, constructed and operated with great care.

“Multiple, different aspects in the team make it work,” said Eric Moyer, deputy project manager ­– technical at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Image above: NASA scientists, engineers and designers pose for a group photo in front of the Terra model. Image Credits: courtesy of Dick Quinn.

“The Terra team includes flight operations, subsystem engineers, subject matter experts, the instrument teams and the science teams for each of the instruments. Overall it all has to be coordinated, so one activity doesn’t negatively impact another instrument,” said Moyer, who worked on Terra during construction and continues to be involved with its operations today.

Dimitrios Mantziaras, Terra mission director at Goddard, summed up what it takes: “A well-built spacecraft, talented people running it and making great science products, with lots of people using the data, that’s what has kept Terra running all these years.”

Designing a Pioneer

Terra was unique from the beginning. It was one of the first satellites to study Earth system science, and the first to look at land, water and the atmosphere at the same time. Unlike many previous, smaller satellites, Terra didn’t have a previously launched satellite platform to build upon. It had to be designed from scratch.

“Unlike the Landsat mission, which continues to improve upon its original design, nothing like Terra had ever been built,” said Dick Quinn, Terra’s spacecraft manufacturing representative from Lockheed Martin, who still works part-time at with the team responsible for Terra’s continued flight.

Image above: Terra’s test team stands in front of the satellite during its construction and testing phase. Image Credits: courtesy of Dick Quinn.

Terra was meant to be the first in a series of satellites, known as AM-1, 2 and 3, each with a design life of about five years. Instead, the mission team ended up designing a satellite that lasted longer than the combined design life of three generations of Terra satellites.

Constructing and Operating a Solid Satellite 

The built-in redundancies and flexibility of the satellite were put to the test in 2009, when a micrometeoroid struck a power cell, degrading the thermal control for the battery.

“We had to change the way we manage the battery to keep it operating efficiently and keep it at the right temperature,” said Jason Hendrickson, Terra flight systems manager at Goddard, who joined the team in 2013. To do this, the team used the charge and discharge cycle of the battery itself to generate the heat necessary to keep the battery operating. They have been finetuning this cycle ever since.

Terra engineers and scientists continually plan for worst-case scenarios, anticipating problems that may never develop.

“We are always thinking, if this were to fail, how are we going to respond?” Hendrickson said. “You can’t just go to the garage and swap out parts.”

Image above: Celebrating the 10th anniversary of Terra in 2009, the flight operations leads and managers posed around a model of the satellite. Image Credits: courtesy of Alan Lampe.

Not only does the team plan for many possible scenarios, but it also looks back at the response and figures out how it can be improved.

However, most of the time, they don’t have to wait for a system failure to practice contingency plans. For example, in 2017 the team executed the second lunar deep space calibration maneuver in Terra’s lifetime. The satellite turned to look at deep space, instead of at Earth.

“We had to take into account what would happen if the computer were to fail when we were pointed at deep space,” Hendrickson said.

Image above: The Terra working group, including representatives from science teams, instruments teams and flight operations teams meet in Boulder, Colorado, in 2015. Image Credits: courtesy of Tassia Owen.

The calibration maneuver was executed successfully and the team never had to conduct their contingency plan. The science gained from calibrating Terra’s data against deep space allowed the scientists to improve the data collected by the ASTER instrument. ASTER, a collaborative instrument with Japan and the United States, is one of five instruments on Terra. It monitors volcanic eruptions, among many other objectives and provides high resolution imagery of locations all over the world.

In addition to ASTER, the instruments on Terra make many contributions and benefit people worldwide:

- The Moderate Imaging Spectroradiometer (MODIS) collects data on land cover, land and sea surface temperatures, aerosol particle properties and cloud cover changes. For example, MODIS data is used to protect people’s lives and property through operations like MODIS rapid response, which monitors wildfires daily: https://terra.nasa.gov/about/terra-instruments/modis

- MISR continues to provide data useful for health researchers studying the effects of particulate matter on populations all over the world, as well as fundamental studies of how aerosol particles and clouds affect weather and climate and investigations of terrestrial ecology: https://terra.nasa.gov/about/terra-instruments/misr

- Measurements of Pollution in the Troposphere (MOPITT), a collaboration with the Canadian Space Agency, is used to study carbon monoxide in the atmosphere, an indicator of pollution concentrations, also a contributor to global health issues: https://terra.nasa.gov/about/terra-instruments/mopitt

- Clouds and Earth’s Radiant Energy System (CERES) provides data on Earth’s energy budget, helping monitor the outgoing reflected solar and emitted infrared radiation of the planet: https://terra.nasa.gov/about/terra-instruments/ceres

The science teams for each instrument work with the operations and technical teams to ensure that the scientific data provided is accurate and useful to the researchers who access it.

Image above: The offline Terra mission operations team stands in front of an image of the fleet of NASA Earth Observing Satellites. Image Credits: courtesy of Jason Hendrickson.

The data is free and is valued by people all over the world. Not only can it be accessed daily, there are over 240 direct broadcast sites, where data can be downloaded in near real-time, all over the world. Moyer said that one of the most rewarding parts of working with Terra is that “the science data is truly valued by people we don’t even know. People all over the world.”

ASTER: https://terra.nasa.gov/about/terra-instruments/aster

Terra Satellite: http://www.nasa.gov/mission_pages/terra/index.html

For more information on Terra, visit: https://terra.nasa.gov

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

Best regards, Orbiter.ch

Soyuz MS-10 - Emergency landing after a failure

ROSCOSMOS - Soyuz MS-10 Mission patch.

Oct. 11, 2018

The Soyuz rocket a few seconds after the launch

The rocket, which took off Thursday for the International Space Station with two occupants on board, experienced an engine problem.

US astronaut Nick Hague and Russian Alexey Ovchinin landed and are unhurt after failure shortly after taking off one of the engines of the Soyuz rocket that was to transport them to the International Space Station (ISS).

"When the Soyuz MS-10 took off, an unusual situation arose. Rescue systems were activated, the ship landed in Kazakhstan. The crew is alive and the contact has been established with him, "the Russian space agency Roskosmos said in a statement.

Launch of Soyuz MS-10

Video above: A Soyuz-FG rocket launched the Soyuz MS-10 spacecraft with International Space Station Expedition 57-58 crew members, NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin, from the Baikonur Cosmodrome in Kazakhstan, on 11 October 2018, at 08 : 40 UTC (14:40 local time). Due to a booster error, the spacecraft entered a ballistic descends and the crew landed in Kazakhstan. Video Credits: Roscosmos TV / NASA TV.

"The rescue teams are heading to the landing zone of the Soyuz ship carrying the two men," Nasa added on Twitter. A source in the Russian space sector, quoted by Ria Novosti, added that the two men "were not injured" after the failure of one of the engines of the Soyuz rocket that was to override the ISS.

Soyuz MS-10 launch failure

Video above: A Soyuz-FG rocket launched the Soyuz MS-10 spacecraft with International Space Station Expedition 57-58 crew members, NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin, from the Baikonur Cosmodrome in Kazakhstan, on 11 October 2018, at 08 : 40 UTC (14:40 local time). Due to a booster error, the spacecraft entered a ballistic descends and the crew landed in Kazakhstan. Video Credits: Roscosmos TV / NASA TV.

The Soyuz rocket, which was to take the two men on a six-month mission to the orbital station, failed about two minutes after taking off. "Throwing problem, two minutes and 45 seconds," announced in a perfectly calm voice Alexey Ovchinin, captain of the rocket Soyuz, in the live broadcast of the takeoff.

Soyuz MS-10 escape capsule landing with both crew members safe and sound

"There was a problem with the engine a few seconds after the separation of the first stage of the rocket," said NASA commentators, who broadcast the launch live.

Soyuz MS-10 crew safe after booster failure

According to an AFP photographer on the spot, the takeoff went well but "after the separation of the first floor, we had the impression that there was a kind of flash". "Thank God they are alive," Kremlin spokesman Dmitry Peskov told reporters.

Roscosmos Press Release: https://www.roscosmos.ru/25594/

Related links:

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images, Videos, Text, Credits: ROSCOSMOS/NASA/AFP/ROSCOSMOS TV/NASA TV/SciNews/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

New Crew Less Than A Day From Launching to Station

ISS - Expedition 57 Mission patch.

October 10, 2018

NASA astronaut Nick Hague and Roscosmos cosmonaut Alexey Ovchinin are in Kazakhstan less than a day away from launching to the International Space Station. They will blast off atop the Soyuz MS-10 spacecraft Thursday at 4:40 a.m. EDT for a six-hour ride to their new home in space.

Image above: At the Baikonur Cosmodrome in Kazakhstan, Expedition 57 crew members Alexey Ovchinin of Roscosmos (left) and Nick Hague of NASA (right) pose for pictures in front of their Soyuz MS-10 spacecraft Sept. 26 during final pre-launch training. Image Credit: NASA.

They will meet their Expedition 57 crew mates aboard the orbiting lab after their Soyuz crew ship docks to the Poisk module at 10:44 a.m. Commander Alexander Gerst and Flight Engineers Serena Auñón-Chancellor and Sergey Prokopyev will greet the new duo when the Soyuz hatch opens around 12:45 p.m.

The five-person crew will gather inside the Zvezda service module for a traditional crew greeting ceremony as family and mission officials on the ground offer their well-wishes. Shortly afterward, the two new crewmates will participate in a safety briefing then begin several days of familiarization with station systems.

The Space Station Transits Our Sun

Image above: This composite image, made from nine frames, shows the International Space Station, with a crew of three onboard, in silhouette as it transits the Sun at roughly five miles per second, Sunday, Oct. 7, 2018. Onboard are Commander Alexander Gerst of the European Space Agency, Serena Auñón-Chancellor of NASA, and Sergey Prokopyev of Roscosmos. The trio will soon be joined by Nick Hague of NASA and Alexey Ovchinin of Roscosmos, who are scheduled to launch on October 11 from the Baikonur Cosmodrome in Kazakhstan. Image Credits: NASA/Joel Kowsky.

NASA TV begins its live broadcast Thursday at 3:30 a.m. as the crew counts down to its launch from the Baikonur Cosmodrome. NASA TV will be back on the air at 10 a.m. four orbits later as the Soyuz spacecraft approaches the station for docking. Finally, live coverage of the hatch opening and crew greeting begins at 12:15 p.m.

Image from International Space Station of the Eye of Hurricane Michael

Image above: A view of the eye of Hurricane Michael taken on Oct. 10, 2018 from the International Space Station currently orbiting Earth. The photo was taken by astronaut Dr. Serena M. Auñón-Chancellor, who began working with NASA as a Flight Surgeon in 2006. In 2009, she was selected as a NASA astronaut. Image Credit: NASA.

Related links:

NASA TV: https://www.nasa.gov/nasatv

Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia/Yvette Smith.

Best regards, Orbiter.ch

NASA Analyzes Category 4 Hurricane Michael Approaching Landfall

NASA & NOAA - Suomi NPP satellite patch.

Oct. 10, 2018

Michael (Gulf of Mexico) 2018

NASA-NOAA’s Suomi NPP satellite examined Hurricane Michael after it reached Category 4 status and neared the Florida Panhandle on Oct. 10. Suomi NPP provided an infrared and night-time view of the powerful storm.

Image above: NASA-NOAA’s Suomi NPP satellite obtained a night-time view of Hurricane Michael in the Gulf of Mexico on Oct. 10 at 0732 UTC (2:32 a.m. CDT). At the time, Michael was a Category 4 hurricane and the eye was so well-defined it could be seen clearly by moonlight. Lights from population centers along the Gulf coast appear white. Image Credits: NASA/NOAA/UW-SSEC-CIMSS, William Straka III.

At 9 a.m. EDT on Oct. 10, water levels were quickly rising and winds increasing along the Florida panhandle as potentially catastrophic Michael approached.

Satellite Imagery Reveal

NASA-NOAA’s Suomi NPP satellite obtained an infrared view of Hurricane Michael in the Gulf of Mexico on Oct. 10 at 0732 UTC (2:32 a.m. CDT). At the time, Michael was a Category 4 hurricane and the eye was so well-defined it could be seen clearly by moonlight. Infrared imagery revealed strong thunderstorms and tropospheric gravity waves in the northwest and western and eastern edges of the hurricane.

NASA-NOAA’s Suomi NPP satellite. Image Credits: NASA/NOAA

National Hurricane Center forecaster Daniel Brown described Hurricane Michael in visible and infrared imagery, “Michael is an extremely impressive hurricane in visible and infrared satellite imagery this morning. The eye has continued to warm and become even more distinct, while remaining embedded within an area of very cold cloud tops.”

Many Warnings and Watches in Effect

NOAA’s National Hurricane Center has noted many warnings and watches in effect.

Image above: NASA-NOAA’s Suomi NPP satellite obtained an infrared view of Hurricane Michael in the Gulf of Mexico on Oct. 10 at 0732 UTC (2:32 a.m. CDT). At the time, Michael was a Category 4 hurricane and the image revealed strong thunderstorms and tropospheric gravity waves in the northwest and western and eastern edges of the hurricane. Image Credits: NASA/NOAA/UW-SSEC-CIMSS, William Straka III.

A Storm Surge Warning is in effect for Okaloosa/Walton County Line, Florida to Anclote River, Florida. A Storm Surge Watch is in effect from Anclote River, Florida to Anna Maria Island Florida, including Tampa Bay. A Hurricane Warning is in effect from the Alabama/Florida border to Suwannee River, Florida. A Tropical Storm Warning is in effect from the Alabama/Florida border to the Mississippi/Alabama border and from Suwanee River Florida to Chassahowitzka, Florida and north of Fernandina Beach, Florida to Surf City, North Carolina. A Tropical Storm Watch is in effect from Chassahowitzka to Anna Maria Island, Florida, including Tampa Bay; from the Mississippi/Alabama border to the Mouth of the Pearl River; from Surf City, North Carolina to Duck, North Carolina, and for the Pamlico and Albemarle Sounds.

For updated forecasts, visit: http://www.nhc.noaa.gov/

For local warnings and forecasts, visit: http://www.weather.gov/

NASA's Suomi NPP satellite: https://www.nasa.gov/mission_pages/NPP/main/index.html

Images (mentioned), Text, Credits: NASA’s Goddard Space Flight Center, by Rob Gutro.

Greetings, Orbiter.ch

‘Pulsar in a Box’ Reveals Surprising Picture of a Neutron Star’s Surroundings

NASA - Fermi Gamma-ray Space Telescope logo.

Oct. 10, 2018

An international team of scientists studying what amounts to a computer-simulated “pulsar in a box” are gaining a more detailed understanding of the complex, high-energy environment around spinning neutron stars, also called pulsars. The model traces the paths of charged particles in magnetic and electric fields near the neutron star, revealing behaviors that may help explain how pulsars emit gamma-ray and radio pulses with ultraprecise timing.

“Efforts to understand how pulsars do what they do began as soon as they were discovered in 1967, and we’re still working on it,” said Gabriele Brambilla, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the University of Milan who led a study of the recent simulation. “Even with the computational power available today, tracking the physics of particles in the extreme environment of a pulsar is a considerable challenge.”

A pulsar is the crushed core of a massive star that ran out of fuel, collapsed under its own weight and exploded as a supernova. Gravity forces more mass than the Sun’s into a ball no wider than Manhattan Island in New York City while also revving up its rotation and strengthening its magnetic field. Pulsars can spin thousands of times a second and wield the strongest magnetic fields known.

New Sumilation Creates "Pulsar in a Box"

Video above: Explore a new “pulsar in a box” computer simulation that tracks the fate of electrons (blue) and their antimatter kin, positrons (red), as they interact with powerful magnetic and electric fields around a neutron star. Lighter tracks indicate higher particle energies. Each particle seen in this visualization actually represents trillions of electrons or positrons. Better knowledge of the particle environment around neutron stars will help astronomers understand how they produce precisely timed radio and gamma-ray pulses. Video Credits: NASA’s Goddard Space Flight Center.

These characteristics also make pulsars powerful dynamos, with superstrong electric fields that can rip particles out of the surface and accelerate them into space.

NASA’s Fermi Gamma-ray Space Telescope has detected gamma rays from 216 pulsars. Observations show that the high-energy emission occurs farther away from the neutron star than the radio pulses. But exactly where and how these signals are produced remains poorly known.

Various physical processes ensure that most of the particles around a pulsar are either electrons or their antimatter counterparts, positrons.

“Just a few hundred yards above a pulsar’s magnetic pole, electrons pulled from the surface may have energies comparable to those reached by the most powerful particle accelerators on Earth,” said Goddard’s Alice Harding. “In 2009, Fermi discovered powerful gamma-ray flares from the Crab Nebula pulsar that indicate the presence of electrons with energies a thousand times greater.” 

Speedy electrons emit gamma rays, the highest-energy form of light, through a process called curvature radiation. A gamma-ray photon can, in turn, interact with the pulsar’s magnetic field in a way that transforms it into a pair of particles, an electron and a positron.

Fermi Gamma-ray Space Telescope. Image Credit: NASA

To trace the behavior and energies of these particles, Brambilla, Harding and their colleagues used a comparatively new type of pulsar model called a “particle in cell” (PIC) simulation. Goddard’s Constantinos Kalapotharakos led the development of the project’s computer code. In the last five years, the PIC method has been applied to similar astrophysical settings by teams at Princeton University in New Jersey and Columbia University in New York.  

“The PIC technique lets us explore the pulsar from first principles. We start with a spinning, magnetized pulsar, inject electrons and positrons at the surface, and track how they interact with the fields and where they go,” Kalapotharakos said. “The process is computationally intensive because the particle motions affect the electric and magnetic fields and the fields affect the particles, and everything is moving near the speed of light.”

The simulation shows that most of the electrons tend to race outward from the magnetic poles. The positrons, on the other hand, mostly flow out at lower latitudes, forming a relatively thin structure called the current sheet. In fact, the highest-energy positrons here — less than 0.1 percent of the total — are capable of producing gamma rays similar to those Fermi detects, confirming the results of earlier studies.

Some of these particles likely become boosted to tremendous energies at points within the current sheet where the magnetic field undergoes reconnection, a process that converts stored magnetic energy into heat and particle acceleration.

Animation above: Electrons (blue) and positrons (red) from a computer-simulated pulsar. These particles become accerlated to extreme energies in a pulsar's powerful magnetic and electric fields; lighter tracks show particles with higher energies. Each particle seen here actually represents trillions of electrons or positrons. Better knowledge of the particle environment around neutron stars will help astronomers understand how they behave like cosmic lighthouses, producing precisely timed radio and gamma-ray pulses. Animation Credits: NASA's Goddard Space Flight Center.

One population of medium-energy electrons showed truly odd behavior, scattering every which way — even back toward the pulsar.

The particles move with the magnetic field, which sweeps back and extends outward as the pulsar spins. Their rotational speed rises with increasing distance, but this can only go on so long because matter can’t travel at the speed of light.

The distance where the plasma’s rotational velocity would reach light speed is a feature astronomers call the light cylinder, and it marks a region of abrupt change. As the electrons approach it, they suddenly slow down and many scatter wildly. Others can slip past the light cylinder and out into space.

The simulation ran on the Discover supercomputer at NASA’s Center for Climate Simulation at Goddard and the Pleiades supercomputer at NASA’s Ames Research Center in Silicon Valley, California. The model actually tracks “macroparticles,” each of which represents many trillions of electrons or positrons. A paper describing the findings was published May 9 in The Astrophysical Journal.

“So far, we lack a comprehensive theory to explain all the observations we have from neutron stars. That tells us we don’t yet completely understand the origin, acceleration and other properties of the plasma environment around the pulsar,” Brambilla said. “As PIC simulations grow in complexity, we can expect a clearer picture.”

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.

Related links:

Discover supercomputer: https://www.nccs.nasa.gov/services/discover

Pleiades supercomputer: https://www.nas.nasa.gov/hecc/resources/pleiades.html

The Astrophysical Journal: http://iopscience.iop.org/article/10.3847/1538-4357/aab3e1/meta

For more about NASA’s Fermi mission, visit: https://www.nasa.gov/fermi

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

Greetings, Orbiter.ch