Tag: Eugene Parker

Space News for April 2022     

It’s on the launch pad, years late and billions of dollars over budget but the Space Launch System (SLS), the most powerful rocket since the venerable Saturn 5 that took astronauts to the moon is finally at Pad 39B at Cape Kennedy, ready for lunch. Well almost ready because the engineers and scientists at both NASA and prime contractor Boeing still have a long list of tests and safety checks to perform before the actual first flight in the space agency’s Artemis program begins. The biggest test, known as the Wet Dress Rehearsal or WDR, is now scheduled for the 1-3 of April.

NASA made a big deal out of the rollout of the SLS to its launch pad, even streaming the entire event. The rocket still has problems however and will soon be taken back to the Vehicle Assembly Building for repairs. (Credit: Forbes)

The rollout of the massive SLS with its Orion, man capable capsule took place on March 17th as the door of the Vehicle Assembly Building opened and the SLS began its long, slow journey to the launch site. The current schedule is for launch to take place no earlier than sometime in May. That first flight will be unmanned, with the second Artemis mission, and the first mission that will actually take astronauts back to orbiting the Moon, coming no sooner than 2024.

The Orion Capsule on top of the SLS. NASA plans to use Orion to take astronauts back to the Moon and even beyond but without the SLS its going nowhere fast. (Credit: EarthSky)

Update: The SLS was on its launch pad but after failing to complete the WDR three times NASA has decided to return the rocket to the Vehicle Assembly Building for repairs. Just another in a long series of delays and problems for the Artemis program that is years behind schedule and billions of dollars over budget.

The rollback of the SLS itself been delayed by weather, just more delays. The current schedule is for a rollback on 26April. (Credit: Spaceflight Insider)

And even as NASA begins the Artemis program to take human beings back to the Moon the space agency is making plans to also return to a destination much further away, the outer planets of Uranus and Neptune. The only space probe to have visited those cold, dark worlds was Voyager 2, which flew past them in the late 1980s. At the time the data sent back by Voyager taught us more about the two outermost planets in our Solar System than we’d learned in more than a hundred years of observing them by Earth bound telescopes. In the years since Voyager however astronomers have come up with thousands of questions about conditions on Uranus and Neptune that they’d love to see answered.

Currently the Voyage 2 probe is the only spacecraft to visit the planet Uranus. Now NASA has made the decision to return to this icy world in the next decade. (Credit: Drew Ex Machina)

So plans are now being discussed for a joint NASA-ESA mission to the outer planets. Details are sketchy at the moment, even so far as to which planet will be visited, or maybe both. The best upcoming launch window for Uranus is 2030-2034 while that for Neptune is 2029-2030 so the particulars for the mission along with the basic space probe design will probably have to be finalized in the next year or so. One thing that has been decided is that the main probe will carry with it a smaller ‘entry probe’ like the Huygens probe that landed on Titan after being carried to Saturn by the Cassini spacecraft. 

Conceptual design for the proposed Uranus probe. The spacecraft will include a separate probe to be dropped into the atmosphere of Uranus. (Credit: Spaceflight Now)

The journey to Uranus or Neptune will be a long one, anywhere from 11 to 15 years depending on the specifics of both the probe and the mission. Because the journey will take so long, and will take the probe so far away from the Sun, using solar arrays to power the spacecraft will be impossible, sunlight simply isn’t strong enough that far from the Sun. So therefore the Uranus / Neptune probe will have to get it’s power from radioisotope thermoelectric generators (RTGs) just as both Voyagers along with Cassini and the Galileo probe to Jupiter did.

Radioisotope Thermoelectric Generators (RTGs) have powered many space probes but they have also been used here on Earth to power instruments in very isolated areas. (Credit: Bellona.org)

Sounds like an exciting mission, wouldn’t it be nice if they could find the money to send identical probes to each planet!

The planet Neptune hasn’t had a visitor for a long time either. Wouldn’t it be nice if we could send a probe to both of them! (Credit: NASA)

A sad note before I sign off. Eugene Parker died on March 15th at the age of 94. The highly regarded NASA astrophysicist is best remembered for his 1957 prediction of the solar wind, the stream of charged particles that are constantly being emitted from the Sun’s atmosphere. That prediction was confirmed just five years later when the Mariner 2 space probe was constantly bombarded during its journey to Venus by just the sort of radiation that Parker had predicted.

In many ways the life of Eugene Parker was a mission to touch the Sun. That’s why it’s so appropriate for NASA’s solar probe to be named for him. (Credit: SciTechDaily)

Eugene Parker is also remembered as the namesake of NASA’s Parker Solar Probe which since its launch in 2018 has now approached closer to the Sun than any other man made object. The Parker probe was the first, and thus far only space probe to be named for a living scientist. A fitting tribute to a man who advanced our knowledge of the Sun so much.

NSA releases the first results from the Parker Solar Probe.

Without our Sun life here on Earth would be impossible, we all know that. The Sun’s light not only keeps our planet warm but through the process of photosynthesis generates the food we need to survive. Recognizing this importance for centuries now scientists have examined the Sun with every instrument in their possession. However the very energy that the Sun produces can make it difficult to study. After all, if you get too close you could suffer the same fate as Icarus.

Right now our Sun is going through Solar minimum in its 11 year sunspot cycle. We have had 271 days with NO observable sunspots so far this year. (Credit: Spaceweather.com)

NASA’s Parker Solar probe is the space agency’s latest attempt to get up close and personal with our parent star. Launched back on August 12th of 2018, see my posts of 7 June 2017, 5 September 2018 and 3 November 2018, Parker is designed with a special ‘heat shield’ to protect its delicate instruments from being destroyed by the Sun’s heat. Nevertheless even Parker cannot remain too near the Sun for too long. Instead the probe has been placed in a highly elliptical orbit that takes it in as close as 24 million kilometers to the Sun before sending it back out to 100 million kilometers, a distance that will allow the that heat shield a chance to cool off.

The Parker Solar probe nearly completion. The heat reflector / shield at the top protects the delicate instruments beneath from the Sun’s intense radiation. (Credit: Axios.com)
The planned orbital plot for the Parker Solar Probe is the most complex set of maneuvers ever attempted for a spacecraft. (Credit: Sky and Telescope)

At its closest approach Parker actually flies within the Sun’s atmosphere, the corona, that glow around the Sun that can only be seen during a total eclipse. The question of why the corona is so hot, over a million degrees Kelvin, while the Sun’s surface is relatively cool, about 6,000 Kelvin, is one of the mysteries that Parker was built to study.

A picture I took of the solar eclipse back in August of 2017. At totality the Sun’s corona becomes visible. (Credit: R. A. Lawler)

Learning more about the how the Sun generates the Solar wind, the steam of high-energy particles that among other thing causes auroras here on Earth, is another of the Parker Probe’s main missions. That particular mission is only appropriate since the spacecraft is named for Eugene Parker; the astrophysicist who back in the late 1950s first predicted the existence of the Solar wind. In fact Parker is the first NASA spacecraft to be named for a living scientist, a measure of the respect with which Eugene Parker is held in the space community.

Eugene Parker describing the Solar wind that he predicted. (Credit: CNN.com)

So far the Parker Solar probe has completed three of its planned 24 close passes and now NASA has released the first data dump of measurements taken by the probe. In a series of papers presented at the fall meeting of the American Geophysical Union on December 11th NASA scientists revealed new discoveries about how the Sun generates the Solar wind along with how the magnetic fields within the corona switch polarities on a period ranging from a few seconds to a few minutes.

The papers also detail how the density of dust particles in the atmosphere actually goes down as you get closer to the Sun. This phenomenon is probably due to the pressure of the light and sub-atomic particles being ejected by the Sun and of which the Solar wind is formed. During its most recent close approach back in November Parker was actually able to observe the effect of a Coronal Mass Ejection (CME) on the Solar wind revealing how a CME acts as a ‘snowplow’ pushing the wind ahead of it with increased energy.

A Coronal Mass Ejection (CME). (Credit: Flickr)

And the Parker probe’s mission is only beginning; NASA is planning on another 21 close approaches to the Sun. In fact just next month Parker is scheduled to use a gravity assist from the planet Venus which will send it on an orbit that takes it even closer to the Sun. Eventually the space probe is expected to come within a mere 6.16 million kilometers of the Sun and to reach speeds of 690,000 kilometers per hour, a wild ride indeed.

The Parker Solar probe’s mission is scheduled to last through 2025, who knows what secrets it will learn in that time about the star that is the very center of our Solar system.

Space Weather

So far this year has turned out to be a pretty mild one as far as Space Weather is concerned. What’s Space Weather, you ask? Isn’t space a vacuum and you can’t have weather is a vacuum, can you?

It is certainly true that the density of matter in the space between Earth, the Moon and the other planets is usually less than ten atoms per cubic centimeter, that’s less than one billionth billionth of air density at sea level! Not only is the density extremely low but the matter that is out there is usually in the form of elementary particles, protons and electrons rather than stable atoms. How could such nothing have anything that could be called weather?

Well it turns out that while there may not be very much out there, what there is has a lot of energy in it. In fact those few protons and electrons go speeding through the Solar system at more than 10,000 times the wind speed of a hurricane! And since those particles have electric charge at that speed they can generate some pretty powerful voltages and magnetic fields.

As you might guess space weather is almost totally dominated by the Sun with more than a million tons of material evaporating away from the Sun’s surface every second. Known as the Solar Wind this flow of particles was first predicted in 1957 by the astrophysicist Eugene Parker, for whom NASA’s new Parker Solar Probe is named.

Eugene Parker Explaining the Solar Wind (Credit: New York Times)

The Parker Solar Probe (Credit: NASA)

It is the Solar Wind that is responsible for both the Aurora and the belts of radiation that circle the Earth known as the Van Allen belts. Further out in space it is the Solar Wind that generates the tails of comets and which keeps those tails pointing away from the Sun.

Space Weather is Caused by the Sun (Credit: NOAA)

The power of the Solar Wind varies with the Sun’s approximately eleven-year sunspot cycle and right now the Sun has been quite quiet. During periods of intense sunspot activity however the Solar Wind becomes not only more powerful but more erratic, with massive explosions on the Sun’s surface called Solar flairs blasting out millions of tons of material generating events known as Coronal Mass Ejections or CMEs.

Although it went unrecognized at the time, the first detection of a CME striking the Earth occurred in early September in 1859! On the first of September that year British astronomer Richard Carrington noticed a bright spot on the Sun, a Solar flair. The next night, the night of the second a huge auroral display was seen over much of northern hemisphere, even as far south as Panama. At the same time the brand new U.S. telegraph system experienced unexplained electrifications with operators being shocked and telegraph paper being set on fire.

A similar strike by a CME today would destroy most of the satellites we have in orbit and lead to massive electrical blackouts here on Earth. In fact a magnetic storm from the Sun in March of 1989 is credited with causing a total blackout of the Hydro-Quebec power grid in Canada. Also, the effect that so much radiation might have on astronauts out in space is still unknown but is expected to be a serious health risk.

These days NASA and other space and scientific agencies keep a constant watch on the Sun using satellites such as the joint NASA-ESA Solar Heliospheric (SOHO) and the Solar-Terrestrial Relations Observatory (STEREO) spacecraft. To these satellites will soon be added the Parker Solar Probe, a spacecraft that will travel closer to the Sun than any other man-made device ever has. A daily report for space weather is now being issued to provide warnings for satellite operators, communications corporations as well as power grid utilities.

The SOHO Satellite and an image it took of a Solar Flair (Credit: NASA)

Many scientists and engineers are presently working to develop technologies to protect our electronic infrastructure against the ravages of extreme Space Weather; I know quite a few of them in fact. But the next solar storm could strike at almost any time and there’s a great deal of work to be done. If you’d like to visit NOAA’s website for the daily space weather report click on the link below. (It’s a really cool site!)

https://www.swpc.noaa.gov/

A hundred years ago Space Weather was completely unknown and almost impossible to detect. As our modern societies grow ever more dependent on electronics however the destructive potential of Space Weather is one more way that outer space is now becoming a place that we need to pay close attention to.