Gizmorama - May 21, 2018
It's been a while since we had a few stories about space travel. Today, I have a pair of stories for you. First, Elon Musk's goals for the last version of the Falcon 9 rocket, and then, astronomers discovering a pair of stars orbiting one another at record speed.
Learn about this and more interesting stories from the scientific community in today's issue.
Until Next Time,
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*-- Musk sets goal for two flights in 24 hours with same Falcon 9 rocket --*
Block 5 will be the last version of the Falcon 9 rocket, according to SpaceX CEO and founder Elon Musk.
But before it's retired, Musk hopes Block 5 will significantly alter the economics of rocketry.
In a phone conference with reporters ahead of Thursday's Block 5 launch, Musk said Block 5 will undergo "minor adjustments" here and there, but that the newest version marks the last major overhaul of the Falcon 9.
Even the overhaul wasn't really an overhaul, according to Musk, but rather is the culmination of hundreds of changes that came together to yield a new version -- a new version Musk and SpaceX have high expectations for.
"We expect it to be a mainstay of SpaceX's business," Musk said, "and to complete something of the order of 300 flights before retirement."
Those hundreds of little changes, including upgrades of materials, adding more resilient heat shields, reinforcing various components and boosting engine thrust.
All of the upgrades were made to enhance reusability, Musk said.
"No scheduled maintenance for 10 flights," Musk said. "The only thing that needs to be changed is the propellants being reloaded."
Of course, safety checks will still need to happen, to make sure everything is in working order. And the new payload will have to be loaded onto the rocket. But Musk and SpaceX liken the newest -- and last -- version of the Falcon 9 to an airplane, capable of landing, refueling and flying again on quick turnaround.
"We plan to complete two flights with the same rocket in 24 hours by the end of the year," Musk said. "That would really be amazing."
If each airplane could only fly once, Musk pointed out, air travel would be prohibitively expensive. That's the reality for rockets. SpaceX wants to make space travel more like air travel, with each craft capable of taking several flights. The company expects reusability to slowly bring down the costs of space flight.
After the first ten flights, Block 5 rockets will be refurbished. With refurbishment after every tenth flight, Musk believes a Block 5 rocket will be capable of conducting upwards of 100 flights.
But while only small adjustments are planned for Block 5, the rocket has yet to prove itself. It will have to meet thousands of technical and safety requirements before NASA deems it worthy of carrying manned spacecraft.
The new version gets its first chance to show off on Thursday. After that, Musk and his engineers will take apart the rocket to confirm the rocket is truly capable of rapid reuse.
"It will be a few months before it's ready to fly again," Musk said.
*-- Astronomers find X-ray pulsar in record-fast orbit --*
Scientists have found a pair of stars orbiting one another at record speed.
The duo orbit each other once every 38 minutes, the shortest-known orbital period for its specific class of pulsar binary systems.
The unusual pair, named J17062, was discovered while interrogating the first batch of data recorded by the Neutron star Interior Composition Explorer mission, or NICER mission.
According to researchers, the system is made up of a rapidly spinning, superdense neutron star called an accreting millisecond X-ray pulsar and a hydrogen-poor white dwarf.
"It's not possible for a hydrogen-rich star, like our sun, to be the pulsar's companion," Tod Strohmayer, an astrophysicist at NASA's Goddard Space Flight Center, said in a news release. "You can't fit a star like that into an orbit so small."
Neutron stars are the extremely hot, superdense stellar cores sometimes left over after supernovae. The stars are so hot, they emanate X-rays. Their violent spin and its accretion from its companion causes intense beams of X-rays to pulse from their poles.
NICER data showed J17062 pulses 163 times per second, which means the pulsar is spinning at a speed of 9,800 revolutions per minute. Though J17062 boasts a record orbit, its spin rate is average. Some pulsar spin some 700 revolutions per second, several orders of magnitude greater than J17062 spin rate.
The hotspots that produce the neutron star's polar pulses are created by the accretion of material from its companion, the hydrogen-poor white dwarf. Stolen material is pulled into an accretion disk, much like a black hole. Because the pulsar has an intense magnetic field, the material in the accretion disk are pulled into the stellar core unevenly, creating hotspots.
Over time, the pulsar will accrue more material than it can handle. The excess mass will eventually trigger a thermonuclear reaction, a massive release of energy in the form of X-rays. NICER can detect such releases, but has yet to measure an outburst from J17062.
While the pulsar's donor star is rather puny, it still has a small effect on the orbital path of J17062. That the slight perturbation can be measured is a testament to the sensitivity of NICER's instruments.
"The distance between us and the pulsar is not constant," Strohmayer said. "It's varying by this orbital motion. When the pulsar is closer, the X-ray emission takes a little less time to reach us than when it's further away. This time delay is small, only about 8 milliseconds for J17062's orbit, but it's well within the capabilities of a sensitive pulsar machine like NICER."
Strohmayer and his colleagues detailed their investigation of J17062 in a new paper, published this week in the Astrophysical Journal.
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