Determining the Mass of the Milky Way Using Hypervelocity Stars

An artist's conception of a hypervelocity star that has escaped the Milky Way. Credit: NASA

For centuries, astronomers have been looking beyond our Solar System to learn more about the Milky Way Galaxy. And yet, there are still many things about it that elude us, such as knowing its precise mass. Determining this is important to understanding the history of galaxy formation and the evolution of our Universe. As such, astronomers have attempted various techniques for measuring the true mass of the Milky Way.

So far, none of these methods have been particularly successful. However, a new study by a team of researchers from the Harvard-Smithsonian Center for Astrophysics proposed a new and interesting way to determine how much mass is in the Milky Way. By using hypervelocity stars (HVSs) that have been ejected from the center of the galaxy as a reference point, they claim that we can constrain the mass of our galaxy.

Their study, titled “Constraining Milky Way Mass with Hypervelocity Stars“, was recently published in the journal Astronomy and Astrophysics. The study was produced by Dr. Giacomo Fragione, an astrophysicist at the University of Rome, and Professor Abraham Loeb – the Frank B. Baird, Jr. Professor of Science, the Chair of the Astronomy Department, and the Director of the Institute for Theory and Computation at Harvard University.

Stars speeding through the Galaxy. Credit: ESA

To be clear, determining the mass of the Milky Way Galaxy is no simple task. On the one hand, observations are difficult because the Solar System lies deep within the disk of the galaxy itself. But at the same time, there’s also the mass of our galaxy’s dark matter halo, which is difficult to measure since it is not “luminous”, and therefore invisible to conventional methods of detection.

Current estimates of the galaxy’s total mass are based on the motions of tidal streamers of gas and globular clusters, which are both influenced by the gravitational mass of the galaxy. But so far, these measurements have produced mass estimates that range from one to several trillion solar-masses. As Professor Loeb explained to Universe Today via email, precisely measuring the mass of the Milky Way is of great importance to astronomers:

“The Milky Way provides a laboratory for testing the standard cosmological model. This model predicts that the number of satellite galaxies of the Milky Way depends sensitively on its mass. When comparing the predictions to the census of known satellite galaxies, it is essential to know the Milky Way mass. Moreover, the total mass calibrates the amount of invisible (dark) matter and sets the depth of the gravitational potential well and implies how fast should stars move for them to escape to intergalactic space.”

For the sake of their study, Prof. Loeb and Dr. Fragione therefore chose to take a novel approach, which involved modeling the motions of HVSs to determine the mass of our galaxy. More than 20 HVSs have been discovered within our galaxy so far, which travel at speeds of up to 700 km/s (435 mi/s) and are located at distances of about 100 to 50,000 light-years from the galactic center.

Artist’s conception of a hyperveloctiy star heading out from a spiral galaxy (similar to the Milky Way) and moving into dark matter nearby. Credit: Ben Bromley, University of Utah

These stars are thought to have been ejected from the center of our galaxy thanks to the interactions of binary stars with the supermassive black hole (SMBH) at the center of our galaxy – aka. Sagittarius A*. While their exact cause is still the subject of debate, the orbits of HVSs can be calculated since they are completely determined by the gravitational field of the galaxy.

As they explain in their study, the researchers used the asymmetry in the radial velocity distribution of stars in the galactic halo to determine the galaxy’s gravitational potential. The velocity of these halo stars is dependent on the potential escape speed of HVSs, provided that the time it takes for the HVSs to complete a single orbit is shorter than the lifetime of the halo stars.

From this, they were able to discriminate between different models for the Milky Way and the gravitational force it exerts. By adopting the nominal travel time of these observed HVSs – which they calculated to about 330 million years, about the same as the average lifetime of halo stars – they were able to derive gravitational estimates for the Milky Way which allowed for estimates on its overall mass.

“By calibrating the minimum speed of unbound stars, we find that the Milky Way mass is in the range of 1.2-1.9 trillions solar masses,” said Loeb. While still subject to a range, this latest estimate is a significant improvement over previous estimates. What’s more, these estimates are consistent our current cosmological models that attempt to account for all visible matter in the Universe, as well as dark matter and dark energy – the Lambda-CDM model.

Distribution of dark matter when the Universe was about 3 billion years old, obtained from a numerical simulation of galaxy formation. Credit: VIRGO Consortium/Alexandre Amblard/ESA

“The inferred Milky Way mass is in the range expected within the standard cosmological model,” said Leob, “where the amount of dark matter is about five times larger than that of ordinary (luminous) matter.”

Based on this breakdown, it can be said that normal matter in our galaxy – i.e. stars, planets, dust and gas – accounts for between 240 and 380 billion Solar Masses. So not only does this latest study provide more precise mass constraints for our galaxy, it could also help us to determine exactly how many star systems are out there – current estimates say that the Milky Way has between 200 to 400 billion stars and 100 billion planets.

Beyond that, this study is also significant to the study of cosmic formation and evolution. By placing more precise estimates on our galaxy’s mass, ones which are consistent with the current breakdown of normal matter and dark matter, cosmologists will be able to construct more accurate accounts of how our Universe came to be. One step clsoer to understanding the Universe on the grandest of scales!

Further Reading: Harvard Smithsonian CfA, Astronomy and Astrophysics

SpaceX Targets Saturday Launch of SES-11 after Successful Static Fire Test of Recycled Rocket; Space Coast Gator Gazes in Glee

SpaceX conducts successful static hot fire test of recycled Falcon 9 at Launch Complex 39A at the Kennedy Space Center on 2 Oct 2017 as a gator gazes from Playalinda waterways, FL. Liftoff is slated for 7 Oct 2017 with SES-11/EchoStar 105 telecommunications comsat. Credit: Ken Kremer/Kenkremer.com
SpaceX conducts successful static hot fire test of recycled Falcon 9 at Launch Complex 39A at the Kennedy Space Center on 2 Oct 2017 as a gator gazes from Playalinda waterways, FL. Liftoff is slated for 7 Oct 2017 with SES-11/EchoStar 105 telecommunications comsat. Credit: Ken Kremer/Kenkremer.com

PLAYALINDA/KENNEDY SPACE CENTER, FL – SpaceX is targeting Saturday Oct. 7 for blastoff of the SES-11/EchoStar 105 commercial telecomsat following a successful static fire test of the first stage engines of the ‘used’ Falcon 9 booster, as a Florida Space Coast gator gazed on in wondrous glee as the engines fired away Monday afternoon, Oct. 2.

The brief engine test took place at 430 p.m. EDT (2030 GMT) Monday Oct. 2, with the sudden eruption of smoke and ash rushing out the north facing flame trench and into the air over historic pad 39A on NASA’s Kennedy Space Center during a windy and overcast afternoon – as I witnessed from the Playalinda Beach causeway FL with the jet black hungry gator just feet away from me in the inland waterways.

The static fire test lasted approximately three seconds. The test is routinely conducted by SpaceX engineers to confirm the rockets readiness to launch.

In this case the SpaceX Falcon 9 will refly and relaunch as a recycled rocket.

“Static fire test of Falcon 9 complete,” SpaceX confirmed via tweet soon after the hotfire test was conducted.

“Targeting October 7 launch of EchoStar 105/SES-11 from Pad 39A in Florida.”

SpaceX conducts successful static hot fire test of 3rd previously flown Falcon 9 booster atop Launch Complex 39A at the Kennedy Space Center on 2 Oct 2017 as seen from Playalinda causeway, FL. Liftoff of recycled rocket is slated for 7 Oct 2017 with SES-11/EchoStar 105 telecommunications comsat. Credit: Ken Kremer/Kenkremer.com

The private SES-11/EchoStar 105 mission will launch on a ‘flight-proven’ booster and is slated for a dinnertime lift off on Oct. 7 at 6:53 p.m. EDT from seaside Launch Complex 39A at NASA’s Kennedy Space Center in Florida, carrying the SES-11 telecommunications payload.

SpaceX will also attempt to recover this booster again by soft landing on an ocean going platform prepositioned in the Atlantic Ocean- about 8 minutes after blastoff.

EchoStar 105/SES-11 is a high-powered hybrid Ku and C-band communications satellite launching as a dual-mission satellite for US-based operator EchoStar and Luxembourg-based operator SES.

It will be launched to geostationary orbit some 22,000 miles (36,000 kilometers) above the equator.

The EchoStar 105/SES-11 spacecraft was built by Airbus and shipped from the Airbus facilities in Toulouse, France to Cape Canaveral, FL for flight processing.

SES-11/EchoStar 105 commercial telecomsat. Credit: SES

This is only the third recycled SpaceX Falcon 9 ever to be launched from Pad 39A.

SES was the first company to ever fly a payload on a ‘flight-proven’ Falcon 9. The SES-10 satellite lifted off successfully this spring on March 30, 2017.

Reflown SpaceX Falcon 9 soars to orbit with SES-10 telecomsat from historic Launch Complex 39A at NASA’s Kennedy Space Center in Florida at 6:27 p.m. EDT on March 30, 2017. Credit: Ken Kremer/Kenkremer.com

The second reflown booster successfully launched the BulgariaSat-1 a few months later.

Pad 39A has been repurposed by SpaceX from its days as a NASA shuttle launch pad.

During Monday’s static fire test, the rocket’s first and second stages are fueled with liquid oxygen and RP-1 propellants like an actual launch, and a simulated countdown is carried out to the point of a brief engine ignition.

The hold down engine test with the erected rocket involved the ignition of all nine Merlin 1D first stage engines generating some 1.7 million pounds of thrust at pad 39A while the two stage rocket was restrained on the pad.

SpaceX conducts successful static hot fire test of 3rd previously flown Falcon 9 booster at Launch Complex 39A at the Kennedy Space Center on 2 Oct 2017 as seen from Playalinda causeway, FL. Liftoff is slated for 7 Oct 2017 with SES-11/EchoStar 105 telecommunications comsat. Credit: Ken Kremer/Kenkremer.com

Playalinda Beach is a spectacular place to witness the launch from – while surfing the waves too – if you’re in the area.

The Beach survived Hurricane Irma but suffered serious erosion.

However many favored launch viewing locations were decimated by the Irma’s wind and crashing waves and flooding – as I reported here earlier.

This launch is the first for SpaceX from KSC in the aftermath of Hurricane Irma which forced the center and Cape Canaveral Air Force Station to close several days and postponed this liftoff.

EchoStar 105/SES-11 provides EchoStar with 24 Ku-band transponders of 36 MHz, marketed as EchoStar 105, while it provides SES with a C-band payload of 24 transponders, marketed under the name SES-11, says SES. EchoStar 105/SES-11 replaces Ku-band capacity for AMC-15 and C-band capacity for AMC-18 at SES’ well-established 105 degrees West orbital slot.

Mating of SES-11/EchoStar 105 commercial telecomsat. Credit: SES

SES-11 is the 47th satellite based on Airbus’s highly reliable Eurostar E3000 platform.

The engine test was carried out without the expensive payload attached to the top – a measured instituted since the catastrophic launch pad explosion and loss of the AMOS-6 commercial payload.

Following the hot fire test, the rocket is rolled back to the processing hangar located just outside the pad perimeter fence.

The 5,200 kg satellite will now be integrated with the rocket for the planned weekend liftoff.

The solar arrays generate a spacecraft power of 12 kW.

Watch for Ken’s continuing coverage direct from onsite at the Kennedy Space Center press site and Cape Canaveral Air Force Station.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

This Florida Space Coast gator witnessed the Oct 2, 2017 SpaceX Falcon 9 static fire test for SES-11 comsat while eyeing Ken Kremer/Universe Today from just a few feet away at the Playalinda Causeway waterway. Credit: Ken Kremer/Kenkremer.com

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Learn more about the upcoming ULA Atlas NRO NROL-52 spysat launch on Oct 5 and SpaceX Falcon 9 SES-11 launch on Oct 7, JWST, OSIRIS-REx, NASA missions and more at Ken’s upcoming outreach events at Kennedy Space Center Quality Inn, Titusville, FL:

Oct 4-6, 8: “ULA Atlas NRO NROL-52 spysat launch, SpaceX SES-11, CRS-12 resupply launches to the ISS, Intelsat35e, BulgariaSat 1 and NRO Spysat, SLS, Orion, Commercial crew capsules from Boeing and SpaceX , Heroes and Legends at KSCVC, ULA Atlas/John Glenn Cygnus launch to ISS, SBIRS GEO 3 launch, GOES-R weather satellite launch, OSIRIS-Rex, Juno at Jupiter, InSight Mars lander, SpaceX and Orbital ATK cargo missions to the ISS, ULA Delta 4 Heavy spy satellite, Curiosity and Opportunity explore Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings

Lockheed Martin Unveils Details of their Proposed Base Camp for Mars

Artist's impression of the Mars Base Camp in orbit around Mars. When missions to Mars begin, one of the greatest risks will be that posed by space radiation. Credit: Lockheed Martin

Before NASA can mount its proposed “Journey to Mars“, which will see astronauts set foot on the Red Planet for the first time in history, a number of logistical and technical issues need to be addressed first. In addition to a launch vehicle (the Space Launch System), a crew capsule (the Orion Multi-Purpose Crew Vehicle), and a space station beyond the Moon (the Deep Space Gateway), the astronauts will also need a space habitat in orbit of Mars.

To build this habitat, NASA has reached out to its long-time contractor, Lockheed Martin. And on Saturday, September 28th, at the International Astronautical Congress (IAC) in Adelaide, Australia, the aerospace company revealed new details about its Mars Base Camp. When NASA’s proposed crewed mission to Mars takes place in the 2030s, this base will be the outpost from which crews will conduct research on the Martian surface.

The details revealed at the conference included how their proposed base camp aligns with other key components of NASA’s Mars mission, which Lockheed Martin is also working with NASA to develop. These include the Deep Space Gateway positioned in cislunar orbit, and a Mars surface lander – a reusable, single-stage craft capable of descending to the Martian surface from orbit.

Diagram of Lockheed Martin’s Mars Base Camp. Credit: Lockheed Martin

Along with NASA’s SLS and Orion spacecraft, these vital pieces of infrastructure will allow for not just one, but repeated crewed mission to Mars. As Lisa Callahan – the vice president and general manager of Commercial Civil Space at Lockheed Martin – said in the course of the company’s presentation at the IAC:

“Sending humans to Mars has always been a part of science fiction, but today we have the capability to make it a reality. Partnered with NASA, our vision leverages hardware currently in development and production. We’re proud to have Orion powered-on and completing testing in preparation for its Exploration Mission-1 flight and eventually its journey to Mars.”

Overall, the purpose of the Mars Base Camp is very simple. Basically, it consists of an orbital outpost where scientist-astronauts will be transported to after leaving Earth and flying from the Deep Space Gateway into orbit around Mars. From this base, crews will be able to conduct real-time scientific exploration of the Martian atmosphere, followed by missions to the surface.

As Lockheed Martin’s indicates on their website, the major components of their base camp will be launched separately. Some will be pre-positioned in orbit around Mars ahead of time while others will be assembled in cis-lunar space for the journey to Mars. In the end, six astronauts will launch on an Orion spacecraft – which serves as the heart of the Mars Base Camp interplanetary ship – and assemble all the component in orbit around Mars.

Artist’s impression of Lockheed Martin’s proposed Mars Lander. Credit: Lockheed Martin

This is also consistent with Phase II and Phase III of NASA’s “Journey to Mars”, which are known as the “Proving Ground” and “Earth Independent” phases, respectively. Phase II calls for a series of missions to test the capabilities of the Space Launch System (SLS), Orion spacecraft, and deep space habitats, as well as multiple crewed missions and spacewalks in cislunar space.

Phase III will then consist of the refinement and testing of entry, descent, and landing techniques, as well as in-situ resource utilization. Once these are complete, Phase III will culminate with crewed missions to Martian orbit, followed by landed missions to the Martian surface. The first mission involving the Mars Base Camp are intended to be an extended stay in orbit around the Red Planet.

This will allow astronauts to gain vital experience with extended operations far from Earth and its protective magnetic field. This will be followed by the arrival of the surface lander, which would allow the astronauts to land and conduct missions on the surface. The lander would be mated to the base camp between missions and descend to the surface using supersonic retro-propulsion.

The lander also relies on Orion avionics and systems as its command deck, and is powered by engines that use a liquid-hydrogen/liquid-oxygen propellant. Each mission to the surface would likely last two weeks at a time and consist of four astronauts conducting research and collecting samples for return to the base camp. The crews would then take off in the Lander and return it the station, where it would refuel and restock for future missions.

Artist illustration of Habitation Module. Credit: Lockheed Martin
Artist illustration of Habitation Module. Credit: Lockheed Martin

Since the lander’s fuel can be manufactured from water, it is likely that a source of subsurface water ice will also come into play during these surface missions. If the necessary infrastructure is brought to the surface, it could even be used for the in-situ manufacture of rocket fuel. As such, it is understandable by locating a source of subsurface water ice is a major focal point of future NASA and SpaceX missions.

As noted, the Mars Base Camp is aligned with other mission components, which include the Deep Space Gateway. Here too, NASA has contracted Lockheed Martin to develop the concept’s architecture. This past summer, the company was awarded a Phase II contract by NASA to create designs for this space habitat, which is intended to build on the lessons learned from the International Space Station (ISS).

The contract was awarded as part of the Next Space Technologies for Exploration Partnership (NextSTEP) program, which NASA launched in 2014. In April of 2016, during the second NextSTEP Broad Agency Announcement (NextSTEP-2), NASA selected six U.S. companies to begin building full-sized ground prototypes and concepts for this deep space habitat.

In the end, the Deep Space Gateway and the Mars Base Camp will allow for the development and testing of other space systems in cis-lunar space before sending them on to Mars. The Gateway will also allow astronauts to conduct lunar research and live and work in orbit around the Moon for months at a time. This will come in handy once they begin making transits to and from Mars.

NASA’s Journey to Mars. NASA is developing the capabilities needed to send humans to an asteroid by 2025 and Mars in the 2030s. Credit: NASA/JPL

Ever since NASA first announced its proposal for a “Journey to Mars” in 2010, scientists, space enthusiasts and the general public ave eagerly awaited the release of key details. Given that such a mission comes with major technical and logistical challenges, how they intend to address them has been a major point of interest. Other points of interest have included timelines as well as the vehicles, systems and technologies that would be involved.

This latest announcement is just one of many to be made by NASA and its partners in recent months. As the “Journey to Mars” slowly approaches, more and more details have become available, and what this mission will look like has slowly taken form. As Lockheed Martin states on their website:

Since the first Viking lander touched down on Mars 40 years ago, humanity has been fascinated with the Red Planet. Lockheed Martin built NASA’s first Mars lander and has been a part of every NASA Mars mission since. We’re ready to deliver the future, faster. Mars is closer than you think. We’re ready to accelerate the journey.”

And be sure to check out this promotional video about the Mars Base Camp, courtesy of Lockheed Martin:

Further Reading: Lockheed Martin, LM – Mars Base Camp

Matt William’s New Sci-Fi Book is Out: The Cronian Incident

The Cronian Incident by Matt Williams

It’s time to do a little shameless self promotion for our tireless staff writer Matt Williams. In addition to pumping out an astonishing amount of space news here on Universe Today, Matt is also a science fiction author, having written 10! books. But in the last week, he’s reached a bit of a special milestone: he’s a published science fiction author, thanks to Castrum Press.

Matt’s new book is called The Cronian Incident, and it’s part 1 of a new series called the Formist Series.

Here’s the blurb:

The Cronian Incident by Matthew Williams
The Cronian Incident by Matthew Williams

Just another convict?

A disgraced investigator who once worked the Martian beat, Jeremiah Ward now serves his sentence in a mining colony on Mercury.

His golden opportunity arises when a member of a powerful faction on Titan vanishes and Ward is promised, in exchange for investigating this man’s disappearance, a clean slate and a second chance.

Unwittingly, Ward becomes embroiled in a conspiracy centuries in the making and begins to realise his one shot at redemption may cost him his life.

From terraforming to colonisation, to the Technological Singularity and the future of space exploration; The Cronian Incident is a must read for fans of mystery science fiction.

I haven’t read it yet, but it’s on my list. But I just wanted to give a huge congratulations to Matt. Setting aside the time to write an entire novel is an enormous achievement. To do it while you’re already working a full time job where you write all day? That’s hurculean.

And I know that much of Matt’s work here on Universe Today informed the science he’s using in his stories, especially some of the ideas about terraforming, exotic forms of propulsion, and the future of humanity in space.

Matt hard at work at the office.
Matt hard at work at the office.

Congrats Matt!

Check out his book on Castrum Press

Old Mars Odyssey Data Indicates Presence of Ice Around Martian Equator

A new paper suggests hydrogen-possibly water ice-in the Medusa Fossae area of Mars, which is in an equatorial region of the planet to the lower left in this view. Image Credit: Steve Lee (University of Colorado), Jim Bell (Cornell University), Mike Wolff (Space Science Institute), and NASA

Finding a source of Martian water – one that is not confined to Mars’ frozen polar regions – has been an ongoing challenge for space agencies and astronomers alike. Between NASA, SpaceX, and every other public and private space venture hoping to conduct crewed mission to Mars in the future, an accessible source of ice would mean the ability to manufacture rocket fuel on sight and provide drinking water for an outpost.

So far, attempt to locate an equatorial source of water ice have failed. But after consulting old data from the longest-running mission to Mars in history – NASA’s Mars Odyssey spacecraft – a team of researchers from the John Hopkins University Applied Physics Laboratory (JHUAPL) announced that they may have found evidence of a source of water ice in the Medusae Fossae region of Mars.

This region of Mars, which is located in the equatorial region, is situated between the highland-lowland boundary near the Tharsis and Elysium volcanic areas. This area is known for its formation of the same name, which is a soft deposit of easily-erodible material that extends for about 5000 km (3,109 mi) along the equator of Mars. Until now, it was believed to be impossible for water ice to exist there.

Artist’s conception of the Mars Odyssey spacecraft. Credit: NASA/JPL

However, a team led by Jack Wilson – a post-doctoral researcher at the JHUAPL – recently reprocessed data from the Mars Odyssey spacecraft that showed unexpected signals. This data was collected between 2002 and 2009 by the mission’s neutron spectrometer instrument. After reprocessing the lower-resolution compositional data to bring it into sharper focus, the team found that it contained unexpectedly high signals of hydrogen.

To bring the information into higher-resolution, Wilson and his team applied image-reconstruction techniques that are typically used to reduce blurring and remove noise from medical and spacecraft imaging data. In so doing, the team was able to improve the data’s spatial resolution from about 520 km (320 mi) to 290 km (180 mi). Ordinarily, this kind of improvement could only be achieved by getting the spacecraft much closer to the surface.

“It was as if we’d cut the spacecraft’s orbital altitude in half,” said Wilson, “and it gave us a much better view of what’s happening on the surface.” And while the neutron spectrometer did not detect water directly, the high abundance of neutrons detected by the spectrometer allowed the research team to calculate the abundance of hydrogen. At high latitudes on Mars, this is considered to be a telltale sign of water ice.

The first time the Mars Odyssey spacecraft detected abundant hydrogen was in 2002, which appeared to be coming from subsurface deposits at high latitudes around Mars. These findings were confirmed in 2008, when NASA’s Phoenix Lander confirmed that the hydrogen took the form of water ice. However, scientists have been operating under the assumption that at lower latitudes, temperatures are too high for water ice to exist.

This artist’s concept of the Mars Reconnaissance Orbiter highlights the spacecraft’s radar capability. Credit: NASA/JPL

In the past, the detection of hydrogen in the equatorial region was thought to be due to the presence of hydrated minerals (i.e. past water). In addition, the Mars Reconnaissance Orbiter (MRO) and the ESA’s Mars Express orbiter have both conducted radar-sounding scans of the area, using their Shallow Subsurface Radar (SHARAD) and Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instruments, respectively.

These scans have suggested that there was either low-density volcanic deposits or water ice below the surface, though the results seemed more consistent with their being no water ice to speak of. As Wilson indicated, their results lend themselves to more than one possible explanation, but seem to indicate that water ice could part of the subsurface’s makeup:

“[I]f the detected hydrogen were buried ice within the top meter of the surface. there would be more than would fit into pore space in soil… Perhaps the signature could be explained in terms of extensive deposits of hydrated salts, but how these hydrated salts came to be in the formation is also difficult to explain. So for now, the signature remains a mystery worthy of further study, and Mars continues to surprise us.”

Given Mars’ thin atmosphere and the temperature ranges that are common around the equator – which get as high as 308 K (35 °C; 95 °F) by midday during the summer – it is a mystery how water ice could be preserved there. The leading theory though is that a mixture of ice and dust was deposited from the polar regions in the past. This could have happened back when Mars’ axial tilt was greater than it is today.

The MARSIS instrument on the Mars Express is a ground penetrating radar sounder used to look for subsurface water and ice. Credit: ESA

However, those conditions have not been present on Mars for hundreds of thousands or even millions of years. As such, any subsurface ice that was deposited there should be long gone by now. There is also the possibility that subsurface ice could be shielded by layers of hardened dust, but this too is insufficient to explain how water ice could have survived on the timescales involved.

In the end, the presence of abundant hydrogen in the Medusae Fossae region is just another mystery that will require further investigation. The same is true for deposits of water ice in general around the equatorial region of Mars. Such deposits mean that future missions would have a source of water for manufacturing rocket fuel.

This would shave billions of dollars of the costs of individual mission since spacecraft would not need to carry enough fuel for a return trip with them. As such, interplanetary spacecraft could be manufactured that would be smaller, lighter and faster. The presence of equatorial water ice could also be used to provide a steady supply of water for a future base on Mars.

Crews could be rotated in and out of this base once every two years – in a way that is similar to what we currently do with the International Space Station. Or – dare I say it? – a local source of water could be used to supply drinking, sanitation and irrigation water to eventual colonists! No matter how you slice it, finding an accessible source of Martian water is critical to the future of space exploration as we know it!

Further Reading: NASA

NASA’s Webb Space Telescope Launch Delayed to 2019

The 18-segment gold coated primary mirror of NASA’s James Webb Space Telescope is raised into vertical alignment in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on Nov. 2, 2016. The secondary mirror mount booms are folded down into stowed for launch configuration. Credit: Ken Kremer/kenkremer.com

The 18-segment gold coated primary mirror of NASA’s James Webb Space Telescope is raised into vertical alignment in the largest clean room at the agency’s Goddard Space Flight Center in Greenbelt, Maryland, on Nov. 2, 2016. The secondary mirror mount booms are folded down into stowed for launch configuration. Credit: Ken Kremer/kenkremer.com

The most powerful space telescope ever built will have to wait on the ground for a few more months into 2019 before launching to the High Frontier and looking back nearly to the beginning of time and unraveling untold astronomical secrets on how the early Universe evolved – Engineers need a bit more time to complete the Webb telescopes incredibly complex assembly and testing here on Earth.

Blastoff of NASA’s mammoth James Webb Space Telescope (JWST) has been postponed from late 2018 to the spring of 2019.

“NASA’s James Webb Space Telescope now is planning to launch between March and June 2019 from French Guiana, following a schedule assessment of the remaining integration and test activities,” the agency announced.

Until now the Webb telescope was scheduled to launch on a European Space Agency (ESA) Ariane V booster from the Guiana Space Center in Kourou, French Guiana in October 2018.

“The change in launch timing is not indicative of hardware or technical performance concerns,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at Headquarters in Washington, in a statement.

“Rather, the integration of the various spacecraft elements is taking longer than expected.”

NASA’s says the currently approved budget will not bust the budget or reduce the science output. It “accommodates the change in launch date, and the change will not affect planned science observations.”

NASA’s $8.8 Billion James Webb Space Telescope is the most powerful space telescope ever built and is the scientific successor to the phenomenally successful Hubble Space Telescope (HST).

The Webb Telescope is a joint international collaborative project between NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA).

Up close side-view of newly exposed gold coated primary mirrors installed onto mirror backplane holding structure of NASA’s James Webb Space Telescope inside the massive clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland on May 3, 2016. Aft optics subsystem stands upright at center of 18 mirror segments between stowed secondary mirror mount booms. Credit: Ken Kremer/kenkremer.com

Since Webb is not designed to be serviced by astronauts, the extremely thorny telescope deployment process is designed to occur on its own over a period of several months and must be fully successful. Webb will be positioned at the L2 Lagrange point- a gravitationally stable spot approximately 930,000 miles (1.5 million km) away from Earth.

So its better to be safe than sorry and take the extra time needed to insure success of the hugely expensive project.

NASA’s James Webb Space Telescope sits in Chamber A at NASA’s Johnson Space Center in Houston awaiting the colossal door to close in July 2017 for cryogenic testing. Credits: NASA/Chris Gunn

Various completed components of the Webb telescope are undergoing final testing around the country to confirm their suitability for launch.

Critical cryogenic cooling testing of Webb’s mirrors and science instrument bus is proceeding well inside a giant chamber at NASA’s Johnson Space Center in Texas.

However integration and testing of the complex multilayered sunshield at Northrup Grumman’s Redondo Beach, Ca. facility is taking longer than expected and “has experienced delays.”

The tennis court sized sunshield will protect the delicate optics and state of the art infrared science instruments on NASA’s Webb Telescope.

Webb’s four research instruments cannot function without the essential cooling provided by the sunshield deployment to maintain them at an operating temperature of minus 388 degrees F (minus 233 degrees C).

The Webb telescopes groundbreaking sunshield subsystem consists of five layers of kapton that will keep the optics and instruments incredibly cool, by reducing the incoming sunside facing temperature more than 570 degrees Fahrenheit. Each layer is as thin as a human hair.

All 5 layers of the Webb telescope sunshield installed at Northrop Grumman’s clean room in Redondo Beach, California. The five sunshield membrane layers are each as thin as a human hair. Credits: Northrop Grumman Corp.

“Webb’s spacecraft and sunshield are larger and more complex than most spacecraft. The combination of some integration activities taking longer than initially planned, such as the installation of more than 100 sunshield membrane release devices, factoring in lessons learned from earlier testing, like longer time spans for vibration testing, has meant the integration and testing process is just taking longer,” said Eric Smith, program director for the James Webb Space Telescope at NASA Headquarters in Washington, in a statement.

“Considering the investment NASA has made, and the good performance to date, we want to proceed very systematically through these tests to be ready for a Spring 2019 launch.”

Artist’s concept of the James Webb Space Telescope (JWST) with Sunshield at bottom. Credit: NASA/ESA

Northrop Grumman designed the Webb telescope’s optics and spacecraft bus for NASA’s Goddard Space Flight Center in Greenbelt, Maryland, which manages Webb.

Watch for Ken’s onsite space mission reports direct from the Kennedy Space Center and Cape Canaveral Air Force Station, Florida.

Stay tuned here for Ken’s continuing Earth and Planetary science and human spaceflight news.

Ken Kremer

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Learn more about the upcoming ULA Atlas NRO NROL-52 spysat launch on Oct 5 and SpaceX Falcon 9 SES-11 launch on Oct 7, JWST, OSIRIS-REx, NASA missions and more at Ken’s upcoming outreach events at Kennedy Space Center Quality Inn, Titusville, FL:

Oct 3-6, 8: “ULA Atlas NRO NROL-52 spysat launch, SpaceX SES-11, CRS-12 resupply launches to the ISS, Intelsat35e, BulgariaSat 1 and NRO Spysat, SLS, Orion, Commercial crew capsules from Boeing and SpaceX , Heroes and Legends at KSCVC, ULA Atlas/John Glenn Cygnus launch to ISS, SBIRS GEO 3 launch, GOES-R weather satellite launch, OSIRIS-Rex, Juno at Jupiter, InSight Mars lander, SpaceX and Orbital ATK cargo missions to the ISS, ULA Delta 4 Heavy spy satellite, Curiosity and Opportunity explore Mars, Pluto and more,” Kennedy Space Center Quality Inn, Titusville, FL, evenings

Mission to Metal World Takes a Big Step Forward with Thruster Test

This illustration depicts the spacecraft of NASA's Psyche mission orbiting the metal asteroid Psyche (pronounced SY-kee). Solar power with electric propulsion will be used to propel the spacecraft to Psyche. The asteroid's average distance from the sun is about three times the Earth's distance or 280 million miles. Credit: SSL/ASU/P. Rubin/NASA/JPL-Caltech

As NASA sets its sight on the next generation of space exploration, one area of focus is on missions that can teach us more about our Solar System. This was a major priority during the thirteenth round of NASA’s Discovery Program, which put out the call for proposals back in February of 2014. One of the proposals to make the cut was the Psyche mission, which will send an orbiter to the asteroid of the same name in 2o22.

This mission is unique in that it will entail visiting an asteroid that is entirely composed of metal, which scientists believe is the remnant core of an early planet. For the sake of the mission, NASA’s Glenn Research Center has been working hard to develop a cutting-edge, next-generation thruster that balances power with fuel efficiency. This thruster was recently subjected to tests designed to simulate its journey through space.

Originally discovered in 1852, the object known as 16 Psyche has been a source of fascination ever since astronomers were able to determine its composition. Unlike other asteroids that are largely carbonaceous (C-type), silicate (S-type), or composed of rock and metal (M-type), Psyche is the only asteroid to date that has been found to have an exposed nickel-iron surface.

Because of its unique nature, scientists have theorized that the metal asteroid is actually the core of a Mars-sized planet that formed during the early Solar System. This planet, they theorize, lost its outer layers after experiencing a massive collision, thus leaving an exposed core behind. The study of this asteroid is therefore expected to reveal a great deal about the interior of terrestrial planets and what powers their magnetic fields.

As David Oh, the mission’s lead project systems engineer, said in a recent NASA press release:

“Psyche is a unique body because it is, by far, the largest metal asteroid out there; it’s about the size of Massachusetts. By exploring Psyche, we’ll learn about the formation of the planets, how planetary cores are formed and, just as important, we’ll be exploring a new type of world. We’ve looked at worlds made of rock, ice and of gas, but we’ve never had an opportunity to look at a metal world, so this is brand new exploration in the classic style of NASA.”

The Psyche missions brings together researchers from Arizona State University and experts from NASA’s Jet Propulsion Laboratory. For the sake of designing the engine that would send their spacecraft to its destination, the joint Arizona-JPL team turned to NASA’s Glenn Research Center, which has been conducting research into Solar Electric Propulsion (SEP) for years.

SEP thrusters are essentially ion-engines that rely on electrically-charged inert gases (like xenon) to provide thrust. Like all Hall Effect ion-engines, this allows the thruster to provide a gentle, non-stop stream of thrust that gradually pushes a spacecraft up to greater and greater speeds. Such a system is ideal for deep-space missions where fuel-efficiency is a must.

As Carol Tolbert, the project manager for Psyche thruster testing at NASA Glenn, explained:

“For deep space missions, the type and amount of fuel required to propel a spacecraft is an important factor for mission planners. A SEP system, like the one used for this mission, operates more efficiently than a conventional chemical propulsion system, which would be impractical for this type of mission.”

The Psyche mission, which will be built jointly by JPL and Space Systems Loral (SSL), will use a SPT-140 Hall effect thruster that relies on solar power to provide electrical charges. The reduced fuel mass of this thruster will allow the mission to enter orbit around the metal asteroid while also providing additional space for the mission’s suite of scientific instruments.

These include a multispectral imager, a magnetometer, and a gamma-ray spectrometer, all of which will help the science team to obtain vital information on the asteroid’s origin, composition and history. The SEP also provides flexibility and robustness in the mission flight plan, since it will allow Psyche to get to its destination with greater speed and efficiency than conventional propulsion would allow for.

To test how the thruster performs during low-power operations, engineers at NASA Glenn placed the thruster into a space environment chamber designed to generate the low-pressures and temperatures it will encounter in space. As Carol explained:

“This mission will be the first to use a Hall effect thruster system beyond lunar orbit, so the tests here at Glenn, which had never been conducted before, were needed to ensure the thruster could perform and operate as expected in the deep space environment.”

Artist’s impression of the surface of 16 Psyche. Credit: Arizona State University / NASA

For decades, the Glenn center has used its compliment of chambers to simulate the conditions missions will encounter in space. However, this test is the first time that engineers have sought to determine how an SEP Hall-Effect thruster would fare. As Oh explained, this test is very important since it will simulate precisely how the spacecraft will fly, and the results have been encouraging so far:

“Glenn has a world-class facility that allowed us to go to very low pressures to simulate the environment the spacecraft will operate in and better understand how our thrusters will perform around Psyche. At first glance, the results confirm our predictions regarding how the thruster will perform, and it looks like everything is working as expected. But, we will continue to refine our models by doing more analysis.”

As the team works towards the mission’s proposed launch – which is scheduled for August 2022 – they will use the data collected at NASA Glenn to update their thruster modeling and incorporate it into mission trajectories. Once the spacecraft reaches its destination – the planned arrival will take place by 2026 – it is expected to reveal a great deal about this unique asteroid.

This data is also likely to teach us much about the history of the Asteroid Belt and the Solar System. If indeed 16 Psyche is the remnant of a Mars-sized planet that formed in the Main Belt, it could cause astronomers to rethink their notions of how the Solar System formed and evolved.

Further Reading: NASA

New Study Says Earth Avoided a “Carbon Overdose” During Formation

A new study from the University of Heidelberg suggests that flash-heating and carbon depletion could have been intrinsic to the emergence and evolution of life on Earth. Credit: NASA

According to the Nebular Hypothesis, the Sun and planets formed 4.6 billion years ago from a giant cloud of dust and gas. This began with the Sun forming in the center, and the remaining material forming a protoplanetary disc, from which the planets formed. Whereas the planets in the outer Solar System were largely made up of gases (i.e. the Gas Giants), those closer to the Sun formed from silicate minerals and metals (i.e. the terrestrial planets).

Despite having a pretty good idea of how this all came about, the question of exactly how the planets of the Solar System formed and evolved over the course of billions of year is still subject to debate. In a new study, two researchers from the University of Heidelberg considered the role played by carbon in both the formation of Earth and the emergence and evolution of life.

Their study, “Spatial Distribution of Carbon Dust in the Early Solar Nebula and the Carbon Content of Planetesimals“, recently appeared in the journal Astronomy and Astrophysics. The study was conducted by Hans-Peter Gail, from the Institute for Theoretical Astrophysics at the University of Heidelberg, and Mario Trieloff – from Heidelberg’s Institute of Earth Sciences and the Klaus-Tschira-Laboratory for Cosmochemistry.

A slice of the Allende meteorite with silicate globules of the size of a millimetre. Credit: Institute of Earth Science

For the sake of their study, the pair considered what role the element carbon – which is essential to life here on Earth – played in planetary formation. Essentially, scientists are of the opinion that during the earliest days of the Solar System – when it was still a giant cloud of dust and gas – carbon-rich materials were distributed to the inner Solar System from the outer Solar System.

Out beyond the “Frost Line” – where volatiles like water, ammonia and methane and are able to condense into ice – bodies containing frozen carbon compounds formed. Much like how water was distributed throughout the Solar System, that these bodies were supposedly kicked out of their orbits and sent towards the Sun, distributing volatile materials to the planetesimals that would eventually grow to become the terrestrial planets.

However, when one compares the kinds of meteors that distributed primordial material to Earth – aka. chondrite meteorites –  one notices a certain discrepancy. Basically, carbon is comparatively rare on Earth compared to these ancient rocks, the reason for which has remained a mystery. As Prof. Trieloff, who was the co-author on the study, explained in a University of Heidelberg press release:

“On Earth, carbon is a relatively rare element. It is enriched close to the Earth´s surface, but as a fraction of the total matter on Earth it is a mere one-half of 1/1000th. In primitive comets, however, the proportion of carbon can be ten percent or more.”

Artist’s conception of a solar system in formation. Credit: NASA/FUSE/Lynette Cook

“A substantial portion of the carbon in asteroids and comets is in long-chain and branched molecules that evaporate only at very high temperatures,” added Dr. Grail, the study’s lead author. “Based on the standard models that simulate carbon reactions in the solar nebula where the sun and planets originated, the Earth and the other terrestrial planets should have up to 100 times more carbon.”

To address this, the two researches constructed a model that assumed that short-duration flash-heating events – where the Sun heated the protoplanetary disc – were responsible for this discrepancy. They also assumed that all matter in the inner Solar System was heated to temperatures of between 1,300 and 1,800 °C (2372 to 3272 °F) before small planetesimals and terrestrial planets eventually formed.

Dr. Grail and Trieloff believe the evidence for this lies in the round grains in meteorites that form from molten droplets – known as chondrules. Unlike chondrite meteorites, which can be composed of up to a few percent carbon, chondrules are largely depleted of this element. This, they claim, was the a result of the same flash-heating events that took place before the chondrules could accrete to form meteorites. As Dr. Gail indicated:

“Only the spikes in temperature derived from the chondrule formation models can explain today’s low amount of carbon on the inner planets. Previous models did not take this process into account, but we apparently have it to thank for the correct amount of carbon that allowed the evolution of the Earth’s biosphere as we know it.”

Artist impression of the Late Heavy Bombardment period. Credit: NASA

In short, the discrepancy between the amount of carbon found in chondritic-rock material and that found on Earth can be explained by intense heating in the primordial Solar System. As Earth formed from chrondritic material, the extreme heat caused it to be depleted of its natural carbon. In addition to shedding light on what has been an ongoing mystery in astronomy, this study also offers new insight into how life in the Solar System began.

Basically, the researchers speculate that the flash-heating events in the inner Solar System may have been necessary for life here on Earth. Had there been too much carbon in the primordial material that coalesced into our planet, the result could have been a “carbon overdose”. This is because when carbon becomes oxidized, it forms carbon dioxide, a major greenhouse gas that can lead to a runaway heating effect.

This is what planetary scientists believe happened to Venus, where the presence of abundant CO2 – combined with its increased exposure to Solar radiation – led to the hellish environment that is there today. But on Earth, CO2 was removed from the atmosphere by the silicate-carbonate cycle, which allowed for Earth to achieve a balanced and life-sustaining environment.

“Whether 100 times more carbon would permit effective removal of the greenhouse gas is questionable at the very least,” said Dr. Trieloff. “The carbon could no longer be stored in carbonates, where most of the Earth’s CO2 is stored today. This much CO2 in the atmosphere would cause such a severe and irreversible greenhouse effect that the oceans would evaporate and disappear.”

Artist’s impression of the “Venus-like” exoplanet in a nearby star system. Credit: cfa.harvard.edu

It is a well-known fact that life here on Earth is carbon-based. However, knowing that conditions during the early Solar System prevented an overdose of carbon that could have turned Earth into a second Venus is certainly interesting. While carbon may be essential to life as we know it, too much can mean the death of it. This study could also come in handy when it comes to the search for life in extra-solar systems.

When examining distant stars, astronomers could ask, “were primordial conditions hot enough in the inner system to prevent a carbon overdose?” The answer to that question could be the difference between finding an Earth 2.0, or another Venus-like world!

Further Reading: University of Heidelberg, Astronomy and Astrophysics

Elon Musk Reveals Further Plans to Colonize Mars and Make Aerospace Transit a Reality

The founder of SpaceX said a planned interplanetary transport system would be downsized so it could carry out a range of tasks that would then pay for future Mars missions. Credit: AFP/Peter Parks

For years, Elon Musk and the company he founded to reduce the associated costs of space exploration (SpaceX) have been leading the charge in the development of private spaceflight. Beyond capturing the attention of the world with reusable rocket tests and the development of next-generation space vehicles, Musk has also garnered a lot of attention for his long-term plans.

These plans were the subject of a presentation made on Friday, September 29th, during the International Astronautical Congress (IAC) – which ran from September 25th to September 29th in Adelaide, Australia. During the course of the presentation, Musk detailed his plans to send cargo ships to Mars by 2022 and to conduct regular aerospace trips between major cities here on Earth.

Continue reading “Elon Musk Reveals Further Plans to Colonize Mars and Make Aerospace Transit a Reality”

New Study Sheds Light on How Earth and Mars Formed

Snapshot of a computer simulation of two (relatively small) planets colliding with each other. The colors show how the rock of the impacting body (dark grey, in center of impact area) accretes to the target body (rock; light grey), while some of the rock in the impact area is molten (yellow to white) or vaporised (red). Credit: Philip J. Carter

In accordance with the Nebular Hypothesis, the Solar System is believed to have formed through the process of accretion. Essentially, this began when a massive cloud of dust and gas (aka. the Solar Nebula) experienced a gravitational collapse at its center, giving birth to the Sun. The remaining dust and gas then formed into a protoplanetary disc around the Sun, which gradually coalesced to form the planets.

However, much about the process of how planets evolved to become distinct in their compositions has remained a mystery. Luckily, a new study by a team of researchers from the University of Bristol has approached the subject with a fresh perspective. By examining a combination of Earth samples and meteorites, they have shed new light on how planets like Earth and Mars formed and evolved.

The study, titled “Magnesium Isotope Evidence that Accretional Vapour Loss Shapes Planetary Compositions“, recently appeared in the scientific journal Nature. Led by Remco C. Hin, a senior research associate from the School of Earth Sciences at the University of Bristol, the team compared samples of rock from Earth, Mars, and the Asteroid Vesta to compare the levels of magnesium isotopes within them.

Artist’s impression of the early Solar System, where collision between particles in an accretion disc led to the formation of planetesimals and eventually planets. Credit: NASA/JPL-Caltech

Their study attempted answering what has been a lingering question in the scientific community – i.e. did the planets form the way they are today, or did they acquire their distinctive compositions over time? As Dr. Remco Hin explained in a University of Bristol press release:

“We have provided evidence that such a sequence of events occurred in the formation of the Earth and Mars, using high precision measurements of their magnesium isotope compositions. Magnesium isotope ratios change as a result of silicate vapour loss, which preferentially contains the lighter isotopes. In this way, we estimated that more than 40 per cent of the Earth’s mass was lost during its construction. This cowboy building job, as one of my co-authors described it, was also responsible for creating the Earth’s unique composition.

To break it down, accretion consists of clumps of material colliding with neighboring clumps to form larger objects. This process is very chaotic, and material is often lost as well as accumulated due to the extreme heat generated by these high-speed collisions. This heat is also believed to have created oceans of magma on the planets as they formed, not to mention temporary atmospheres of vaporized rock.

Until planets become about the same size as Mars, their force of gravitational attraction was too weak to hold onto these atmospheres. And as more collisions took place, the composition of these atmosphere and of the planets themselves would have changes substantially. How exactly the terrestrial planets – Mercury, Venus, Earth and Mars – obtained their current, volatile-poor compositions over time is what scientists have hoped to address.

Artist impression of the Late Heavy Bombardment period. Credit: NASA

For example, some believe that the planets current compositions are the result of particular combinations of gas and dust during the earliest periods of planet formation – where terrestrial planets are silicate/metal rich, but volatile poor, because of which elements were most abundant closest to the Sun. Others have suggested that their current composition is a consequence of their violent growth and collisions with other bodies.

To shed light on this, Dr. Hin and his associates analyzed samples of Earth, along with meteorites from Mars and the asteroid Vesta using a new analytical approach. This technique is capable of obtaining more accurate measurements of magnesium isotope rations than any previous method. This method also showed that all differentiated bodies – like Earth, Mars and Vesta – have isotopically heavier magnesium compositions than chondritic meteorites.

From this, they were able to draw three conclusions. For one, they found that Earth, Mars and Vesta have distinct magnesium isotope rations that could not be explained by condensation from the Solar Nebula. Second, they noted that the study of heavy magnesium isotopes revealed that in all cases, the planets lost about 40% percent of their mass during their formation period, following repeated episodes of vaporization.

Last, they determined that the accretion process results in other chemical changes that generate the unique chemical characteristics of Earth. In short, their study showed that Earth, Mars and Vesta all experiences significant losses of material after formation, which means that their peculiar compositions were likely the result of collisions over time. As Dr Hin added:

“Our work changes our views on how planets attain their physical and chemical characteristics. While it was previously known that building planets is a violent process and that the compositions of planets such as Earth are distinct, it was not clear that these features were linked. We now show that vapour loss during the high energy collisions of planetary accretion has a profound effect on a planet’s composition.”

Their study also indicated that this violent formation process could be characteristic of planets in general. These findings are not only significant when it comes to the formation of the Solar System, but of extra-solar planets as well. When it comes time to explore distant star systems, the distinctive compositions of their planets will tell us much about the conditions from which they formed, and how they came to be.

Further Reading: University of Bristol, Nature