1 of 12

Space News Update — August 5, 2013 —

Contents

In the News

Story 1:

The Sun's Magnetic Field is about to Flip

Story 2:

Asteroid sampling mission to launch on Atlas 5 rocket

Story 3:

Bringing down the ISS – Plans for Station’s demise updated

Departments

The Night Sky

ISS Sighting Opportunities

Space Calendar

NASA-TV Highlights

Food for Thought

Space Image of the Week

2 of 12

1. The Sun's Magnetic Field is about to Flip

Something big is about to happen on the sun. According to measurements from NASA-supported

observatories, the sun's vast magnetic field is about to flip.

"It looks like we're no more than 3 to 4 months away from a complete field reversal," says solar physicist Todd

Hoeksema of Stanford University. "This change will have ripple effects throughout the solar system."

The sun's magnetic field changes polarity approximately every 11 years. It happens at the peak of each solar

cycle as the sun's inner magnetic dynamo re-organizes itself. The coming reversal will mark the midpoint of

Solar Cycle 24. Half of 'Solar Max' will be behind us, with half yet to come.

Hoeksema is the director of Stanford's Wilcox Solar Observatory, one of the few observatories in the world that

monitor the sun's polar magnetic fields. The poles are a herald of change. Just as Earth scientists watch our

planet's polar regions for signs of climate change, solar physicists do the same thing for the sun. Magnetograms

at Wilcox have been tracking the sun's polar magnetism since 1976, and they have recorded three grand

reversals—with a fourth in the offing.

Solar physicist Phil Scherrer, also at Stanford, describes what happens: "The sun's polar magnetic fields

weaken, go to zero, and then emerge again with the opposite polarity. This is a regular part of the solar cycle."

A reversal of the sun's magnetic field is, literally, a big event. The domain of the sun's magnetic influence (also

known as the "heliosphere") extends billions of kilometers beyond Pluto. Changes to the field's polarity ripple

all the way out to the Voyager probes, on the doorstep of interstellar space.

3 of 12

When solar physicists talk about solar field reversals, their conversation often centers on the "current sheet."

The current sheet is a sprawling surface jutting outward from the sun's equator where the sun's slowly-rotating

magnetic field induces an electrical current. The current itself is small, only one ten-billionth of an amp per

square meter (0.0000000001 amps/m2), but there‘s a lot of it: the amperage flows through a region 10,000 km

thick and billions of kilometers wide. Electrically speaking, the entire heliosphere is organized around this

enormous sheet.

During field reversals, the current sheet becomes very wavy. Scherrer likens the undulations to the seams on a

baseball. As Earth orbits the sun, we dip in and out of the current sheet. Transitions from one side to another

can stir up stormy space weather around our planet.

Cosmic rays are also affected. These are high-energy particles accelerated to nearly light speed by supernova

explosions and other violent events in the galaxy. Cosmic rays are a danger to astronauts and space probes, and

some researchers say they might affect the cloudiness and climate of Earth. The current sheet acts as a barrier to

cosmic rays, deflecting them as they attempt to penetrate the inner solar system. A wavy, crinkly sheet acts as a

better shield against these energetic particles from deep space.

As the field reversal approaches, data from Wilcox show that the sun's two hemispheres are out of synch.

"The sun's north pole has already changed sign, while the south pole is racing to catch up," says Scherrer.

"Soon, however, both poles will be reversed, and the second half of Solar Max will be underway."

When that happens, Hoeksema and Scherrer will share the news with their colleagues and the public.

Source: NASA Return to Contents

4 of 12

2. Asteroid sampling mission to launch on Atlas 5 rocket

A United Launch Alliance Atlas 5 rocket flying in its unique

configuration with a single strap-on solid booster mounted to the

first stage has been selected to send a NASA spacecraft to

rendezvous with an asteroid and return samples to Earth.

The Origins-Spectral Interpretation-Resource Identification-

Security-Regolith Explorer (OSIRIS-REx) spacecraft is

scheduled for launch in September 2016 from Cape Canaveral,

Florida.

Known as the 411 version of the Atlas 5, the launcher will

feature one solid rocket booster, the kerosene-fueled main stage,

a cryogenic Centaur upper stage and a four-meter-diameter nose cone.

The configuration has flown three times to date, all successfully, since 2006, deploying a commercial European

TV satellite and a pair of classified National Reconnaissance Office missions.

The Atlas design allows planners to tailor the rocket to exact needs of a payload, adding solid motors for greater

liftoff power and various nose cone sizes to enclose the cargo.

"With 39 successful missions spanning a decade of operational service, the commercially developed Atlas 5 is

uniquely qualified to provide launch services for these high-value NASA New Frontier Missions," said Jim

Sponnick, ULA vice president of Atlas and Delta Programs. "Atlas 5 is currently the only launch vehicle

certified by NASA to fly the nation's most complex exploration missions."

Atlas 5 launched for NASA nine times, including two payloads earlier this year -- the TDRS K communications

satellite and the new Landsat. It is slated to send the agency's MAVEN spacecraft to Mars in November and

another TDRS in January.

OSIRIS-REx, equipped with high-resolution cameras, LIDAR and spectrographs, will cruise to the near-Earth

asteroid 101955 Bennu, arriving in October 2018 for a 505-day survey to determine the massive space rock's

composition, chemical makeup and the best spot for sampling.

Approaching at a pace of 3.9 inches per second, the spacecraft will extend a robotic arm to reach the asteroid's

surface, capturing rocks and soil stirred up by blasting nitrogen gas at the surface in a "touch-and-go" maneuver.

The samples will be stowed in a return capsule and brought back to Earth in September 2023 for a parachute-

assisted touchdown.

Asteroid 101955 Bennu orbits the sun every 1.2 years on a path that comes close to Earth every six years.

Precisely measuring its orbit is seen as critical since recent calculations resulted a 1 in 1,800 chance of impact

with Earth in 2182.

Samples collected by the mission will be taken to the Johnson Space Center's curation facility for world-wide

distribution and scientific analysis.

Source: Spaceflight Now Return to Contents

5 of 12

3. Bringing down the ISS – Plans for Station’s demise updated

The latest meeting of NASA‘s Aerospace Safety

Advisory Panel (ASAP) was briefed on an updated

action plan pertaining to the End Of Life (EOL)

scenario for the International Space Station (ISS). The

plan for a destructive deorbit of the Station is required

in the event of a serious contingency resulting in the

evacuation of the crew.

The orbital outpost is currently set to continue flying

until at least 2020, although ongoing studies are being

used to evaluate how long the ISS can continue to

perform its duties, especially from the standpoint of

the hardware‘s long-term health.

At present, it is hoped the ISS could continue to

operate until at least 2028, pending political and international agreement on the operational requirements and

running costs.

Providing the ISS continues to be mechanically healthy, opting against an extension would be close to

unthinkable.

The Station took decades and billions of dollars to assemble, providing the Space Shuttle fleet with their final

major role ahead of retirement – completing assembly and allowing for the transition to the utilization phase.

With the ISS permanently crewed by up to six international expedition members, resupply ships from Russia,

Europe and Japan take it in turns to restock the Station with vital supplies, while the Russian Soyuz provides the

task of crew rotations.

This fleet of ―Visiting Vehicles‖ has since been joined by the first commercial spacecraft from the United

States, with SpaceX‘s Dragon currently preparing for its fourth visit during CRS-3 (SpX-3) at the end of this

year. Orbital‘s Cygnus spacecraft is also expected to make its first trip to the ISS this summer, ahead of

initiating its Commercial Resupply Services contract obligations.

Commercial space companies are also primed to remove the United States‘ dependence on the Russian Soyuz as

a means of lofting NASA astronauts to the Station.

America‘s domestic launch and crew transportation capability was lost when Atlantis closed out the Space

Shuttle Program (SSP) at the conclusion of STS-135. And, with the aborted Constellation Program (CxP)

failing to allow Orion to take up the role before the middle of this decade, NASA created the Commercial Crew

Program (CCP).

With hundreds of millions of NASA dollars aiding the development of three commercial spacecraft options, the

first ―United States Crew Vehicle‖ (USCV-1) flight is currently manifested for late 2017.

Should the ISS be abandoned in 2020, no more than six USCV missions will have taken place – with the final

flight (USCV-6) supporting the last Expedition to iconic laboratory – per the latest long-term manifest

available.

6 of 12

However, the death of the ISS isn‘t restricted to hardware health or political meddling, it also has to deal with

the inherent risks of flying in space, which forever threaten a contingency scenario.

While the Station is protected against major contingencies via teams of expert engineers on the ground, along

with techniques in space – such as the Debris Avoidance Manuever (DAM) that allows the ISS to move out of

the way of space debris – NASA managers always have to consider the worst case scenarios.

Almost all contingency events should still result in the crew surviving, with two Soyuz spacecraft ready to

provide the role of lifeboats in the event of an evacuation being called. However, a painful decision would then

be required over the fate of the Station itself.

ISS Program manager Mike Suffredini recently briefed the ASAP on such plans at the Marshall Space Flight

Center (MSFC), describing the latest evaluations on what would be an EOL scenario for the Station.

―NASA now has a plan so that in the event the Station must be evacuated, there will be a 14-day period in

which to make a decision on whether or not to bring the ISS down. The Program is setting the contingency plan

in place, although there is still a lot of work to be done,‖ noted the minutes from the meeting.

Previous plans have noted that NASA‘s initial response would be to plan to raise the Station‘s orbit, buying

them potentially years to work out what to do with the abandoned spacecraft – hypothetically allowing for a

potential repair or some form of orbital salvage operation.

However, based on the scenario where the ISS was dying, a controlled deborbit plan is preferred, aided by two

final Visiting Vehicles.

―They will have 180 days to get down to deorbit altitude. This would give them time to get two Russian

Progress vehicles launched to autonomously dock, autonomously transfer propellant to the Service Module, and

to provide propulsion to deorbit. This would provide a good, safe, controlled deorbit.‖

Although the disposal corridor over an uninhabited ocean expanse would be refined nearer the time, the deorbit

and destructive re-entry of the Station would be by far the largest man-made object to make the fiery plunge

back to Earth. A large amount of hardware would likely survive re-entry.

The use of two Progress vehicles is also the current method of execution for the Station per its natural EOL.

―In the past, proposals for using Progress to provide impulse to de-orbit had been discussed,‖ noted a previous

ISS Program overview to the ASAP. ―The Program is developing plans for a single Progress, which would be

used for off-nominal EOL; for the planned EOL, there would be two Progress vehicles that would provide more

impulse and better targeting to hit the impact point.‖

The ASAP noted they are ―very pleased‖ with the progress being made on the EOL scenarios.

―The ASAP raised this issue two or three years ago as the kind of thing to think about ahead of time,‖ added the

minutes. ―At that time, the general thinking was that the response would be to boost the orbit to get the Station

higher; however, after all the analysis was done, it was determined that what will actually be needed is the

opposite.

―The ASAP is pleased that all of this work has been done in advance.‖

Source: NASASpaceflight.com Return to Contents

7 of 12

The Night Sky

Source: Sky & Telescope Return to Contents

Friday, August 9

Early in twilight, about a half hour after sunset, look very low in the west below Venus for the thin crescent

Moon, as shown at right. Binoculars will help.

The Perseid meteor shower is ramping up! Activity is already well under way, and the shower should peak late

Sunday and Monday nights. Read all about it: Get Ready for the 2013 Perseids.

Saturday, August 10

The waxing crescent Moon shines well to the left of Venus low in twilight, as shown above.

Sunday, August 11

The annual Perseid meteor shower should be at its most active late tonight and tomorrow night. (The expected

peak time, 2 p.m. EDT August 12th, is ideal for the Far East; for North America it splits the difference between

the early morning hours of the 12th and 13th.) See our article Get Ready for the 2013 Perseids.

Monday, August 12

During and after dusk, spot Saturn above the waxing crescent Moon in the southwest. Look lower right of the

Moon for Spica. Much higher to their upper right shines Arcturus.

8 of 12

ISS Sighting Opportunities For Denver:

Date Visible Max Height Appears Disappears

Fri Aug 9, 9:25 PM 2 min 19° 19 above NNW 11 above NNE

Fri Aug 9, 11:02 PM 1 min 10° 10 above N 10 above NNE

Sat Aug 10, 8:36 PM 3 min 25° 25 above NNW 11 above NNE

Sat Aug 10, 10:13 PM 1 min 11° 11 above N 10 above NNE

Sun Aug 11, 9:24 PM 2 min 12° 12 above NNW 10 above NNE

Sun Aug 11, 11:02 PM 1 min 12° 11 above N 12 above N

Mon Aug 12, 8:35 PM 2 min 15° 15 above NNW 10 above NNE

Mon Aug 12, 10:13 PM 2 min 11° 10 above N 10 above NNE

Sighting information for other cities can be found at NASA‘s Satellite Sighting Information

NASA-TV Highlights (all times Eastern Daylight Time)

August 9, Friday

9 a.m. - Coverage of the Berthing of the ―Kounotori‖ HTV-4 Cargo Vehicle to the ISS (Installation scheduled

to begin around 9:30 a.m. ET) - JSC (All Channels)

1 p.m. - NASA Google+ Hangout: Wildfire and Climate Change - GSFC (All Channels)

Watch NASA TV online by going to the NASA website. Return to Contents

9 of 12

Space Calendar

Aug 09 - Asteroid 277475 (2005 WK4) Near-Earth Flyby (0.021 AU)

Aug 10 - Asteroid 9997 COBE Closest Approach To Earth (1.611 AU)

Aug 10 - Asteroid 4523 MIT Closest Approach To Earth (2.015 AU)

Aug 11 - Comet C/2013 N4 (Borisov) Closest Approach To Earth (2.055 AU)

Aug 11 - Comet P/2011 JB15 (Spacewatch-Boattini) At Opposition (4.549 AU)

Aug 11 - Asteroid 16421 Roadrunner Closest Approach To Earth (1.013 AU)

Aug 11 - Asteroid 12790 Cernan Closest Approach To Earth (1.341 AU)

Aug 11 - Asteroid 6143 Pythagoras Closest Approach To Earth (1.650 AU)

Aug 11 - Asteroid 3125 Hay Closest Approach To Earth (2.107 AU)

Aug 11 - Asteroid 4969 Lawrence Closest Approach To Earth (2.283 AU)

Aug 12 - Comet 152P/Helin-Lawrence Closest Approach To Earth (2.735 AU)

Aug 12 - Perseids Meteor Shower Peak

Aug 12 - Asteroid 17681 Tweedledum Closest Approach To Earth (0.998 AU)

Aug 12 - Asteroid 69263 Big Ben Closest Approach To Earth (1.599 AU)

Aug 12 - 35th Anniversary (1978), ISEE-3 (ICE) Launch

Source: JPL Space Calendar Return to Contents

10 of 12

Food for Thought

Ancient Astronomical Calendar Discovered in Scotland Predates Stonehenge

by 6,000 Years

A team from the University of Birmingham

recently announced an astronomical discovery in

Scotland marking the beginnings of recorded time.

Announced last month in the Journal of Internet

Archaeology, the Mesolithic monument consists of

a series of pits near Aberdeenshire, Scotland.

Estimated to date from 8,000 B.C., this 10,000 year

old structure would pre-date calendars discovered

in the Fertile Crescent region of the Middle East by

over 5,000 years.

But this is no ordinary wall calendar.

Originally unearthed by the National Trust for

Scotland in 2004, the site is designated as Warren

Field near the town of Crathes. It consists of 12 pits in an arc 54 metres long that seem to correspond with 12

lunar months, plus an added correction to bring the calendar back into sync with the solar year on the date of the

winter solstice.

―The evidence suggests that hunter-gatherer societies in Scotland had both the need and sophistication to track

time across the years, to correct for seasonal drift of the lunar year‖ said team leader and professor of Landscape

Archaeology at the University of Birmingham Vince Gaffney.

We talked last week about the necessity of timekeeping as cultures moved from a hunter-gatherer to agrarian

lifestyle. Such abilities as marking the passage of the lunar cycles or the heliacal rising of the star Sirius gave

cultures the edge needed to dominate in their day.

For context, the pyramids on the plains of Giza date from around 2500 B.C., The Ice Man on display in Bolzano

Italy dates from 3,300 B.C., and the end of the last Ice Age was around 20,000 to 10,000 years ago, about the

time that the calendar was constructed.

―We have been taking photographs of the Scottish landscape for nearly 40 years, recording thousands of

archaeological sites that would never have been detected from the ground,‖ said manager of Aerial projects of

the Royal Commission of Aerial Survey Projects Dave Cowley. ―It‘s remarkable to think that our aerial survey

may have helped to find the place where time was invented.‖

The site at Warren Field was initially discovered during an aerial survey of the region.

The use of such a complex calendar by an ancient society also came as a revelation to researchers. Emeritus

Professor of Archaeoastronomy at the University of Leicester Clive Ruggles notes that the site ―represents a

combination of several different cycles which can be used to track time symbolically and practically.‖

The lunar synodic period, or the span of time that it takes for the Moon to return to the same phase (i.e., New-

to-New, Full-to-Full, etc) is approximately 29.5 days. Many cultures used a strictly lunar-based calendar

11 of 12

composed of 12 synodic months. The Islamic calendar is an example of this sort of timekeeping still in use

today.

However, a 12 month lunar calendar also falls out of sync with our modern Gregorian calendar by 11 days (12

on leap years) per year.

The familiar Gregorian calendar is at the other extreme, a calendar that is strictly solar-based. The Gregorian

calendar was introduced in 1582 and is still in use today. This reconciled the 11 minute per year difference

between the Julian calendar and the mean solar year, which by the time of Pope Gregory‘s reform had already

caused the calendar to ―drift‖ by 10 days since the 1st Council of Nicaea 325 AD.

Surprisingly, the calendar discovered at Warren Field may be of a third and more complex variety, a luni-solar

calendar. This employs the use of intercalary periods, also known as embolismic months to bring the lunar and

solar calendar back into sync.

The modern Jewish calendar is an example of a luni-solar hybrid, which adds an extra month (known as the

2nd

Adar or Adar Sheni) every 2-3 years. This will next occur in March 2014.

The Greek astronomer Meton of Athens noted in 5th

century B.C. that 235 synodic periods very nearly add up to

19 years, to within a few hours. Today, this period bears his name, and is known as a metonic cycle. The

Babylonian astronomers were aware of this as well, and with the discovery at Warren Field, it seems that

ancient astronomers in Scotland may have been moving in this direction of advanced understanding as well.

It‘s interesting to note that the site at Warren Field also predates Stonehenge, the most famous ancient structure

in the United Kingdom by about 6,000 years. 10,000 years ago would have also seen the Earth‘s rotational north

celestial pole pointed near the +3.9th

magnitude star Rukbalgethi Shemali (Tau Herculis) in the modern day

constellation of Hercules. This is due to the 26,000 year wobble of our planet‘s axis known as the precession of

the equinoxes.

The Full Moon nearest the winter solstice also marks the ―Long Nights Moon,‖ when the Full Moon occupies a

space where the Sun resides during the summer months and rides high above the horizon for northern observers

all night. The ancients knew of the five degree tilt that our Moon has in relation to the ecliptic and how it can

ride exceptionally high in the sky every 18.6 years. We‘re currently headed towards a ‗shallow year‘ in 2015,

where the Moon rides low in relation to the ecliptic. From there, the Moon‘s path in the sky will get

progressively higher each year, peaking again in 2024.

Who built the Warren Field ruins along the scenic Dee Valley of Scotland? What other surprises are in store as

researchers excavate the site? One thing is for certain: the ancients were astute students of the sky. It‘s

fascinating to realize how much of our own history has yet to be told!

Source: Universe Today Return to Contents

12 of 12

Space Image of the Week

(click image to view video on Vimeo)

The coolest video of an expanding supernova you'll see today

Image Credit & Copyright: Adam Block

When you look at the Crab Nebula, it's hard to fathom you're seeing exploded star remnants zipping outward

through space at 3 million miles per hour. After all, you could stare all night at the nebula—located some 6,500

light years from Earth—and fail to notice even a hint of motion.

However, if you wait, say, 13 years, you'll definitely detect some movement. That's exactly what professional

astrophotographer Adam Block did, using two images of the Crab Nebula taken more than a decade apart. He

created a video that fades back and forth between the two pictures, allowing you to see the nebula expand.

This animation shows the expansion of the Crab Nebula between the years of 1999 and 2012. 1999 picture was

taken by ESO using the VLT. The more recent picture was taken at the Mount Lemmon SkyCenter using the

0.8m Schulman Telescope. Visit Skycenter.arizona.edu

Source: The Planetary Society Return to Contents