Very brief descriptions, with appropriate links, of current or recent news items.
Capitalism in space: SpaceX today has successfully launched a reused cargo Dragon to ISS.
This is the third flight of this Dragon capsule. They also successfully landed the first stage on their drone ship.
The leaders in the 2019 launch race:
27 China
18 Russia
12 SpaceX
7 Europe (Arianespace)
China leads the U.S. in the national rankings 27 to 24.
According to SpaceX officials, the company is aiming to perform its Dragon launch abort test before the end of this month, and then follow-up with the first manned Dragon mission to ISS in early 2020.
“We’re targeting December,” said [Jessica Jensen, director of Dragon Mission Management at SpaceX] today (Dec. 3) during a news conference discussing tomorrow’s (Dec. 4) planned launch of a robotic Dragon cargo mission to the International Space Station (ISS). “We’ll see if we can get there.”
SpaceX holds a multibillion-dollar NASA contract to ferry astronauts to and from the ISS using Crew Dragon and the Falcon 9. The capsule has already visited the orbiting lab once, on the landmark uncrewed Demo-1 mission this past March. If everything goes well with the [launch abort test], the company will be cleared for the first crewed mission — a test flight known as Demo-2 that will carry NASA astronauts Doug Hurley and Bob Behnken.
Demo-2 is targeted for early 2020, SpaceX founder and CEO Elon Musk has said. Contracted, operational ISS flights would follow shortly thereafter.
NASA officials have repeatedly said that early 2020 is too soon because of the paperwork that SpaceX has to complete prior to launch. It could be that Musk is gently applying pressure on them here to speed up this make-work so that the real business of spaceflight can proceed.
Click for full image.
OSIRIS-REx has completed its high resolution reconnaissance of the four candidate sites on the asteroid Bennu, chosen for possible sample capture during touch-and-go operations planned for the summer of 2020.
In the next few days the science team will decide which of these four sites, shown above, will be the primary and back-up landing locations. The decision however appears challenging, based on the information gathered.
Bennu has also made it a challenge for the mission to identify a site that won’t trigger the spacecraft’s safety mechanisms. During Recon A, the team began cataloguing Bennu’s surface features to create maps for the Natural Feature Tracking (NFT) autonomous navigation system. During the sample collection event, the spacecraft will use NFT to navigate to the asteroid’s surface by comparing the onboard image catalog to the navigation images it will take during descent. In response to Bennu’s extremely rocky surface, the NFT system has been augmented with a new safety feature, which instructs it to wave-off the sampling attempt and back away if it determines the point of contact is near a potentially hazardous surface feature. With Bennu’s building-sized boulders and small target sites, the team realizes that there is a possibility that the spacecraft will wave-off the first time it descends to collect a sample.
Based on the information at the link, plus the presentation by Dante Lauretta, OSIRIS-REx’s principal investigator, given at the asteroid conference I attended in November, I suspect that Nightingale will be primary landing site.
Regardless, it appears the science team has recognized that the landing will difficult, and will likely require multiple attempts before the spacecraft’s navigation system lets it happen.
Embedded below the fold in two parts.
» Read more
Scientists today published four papers outlining the first scientific results obtained during the first two close fly-bys of the Sun by the Parker Solar Probe.
The four papers, now available online from the journal Nature, describe Parker’s unprecedented near-Sun observations through two record-breaking close flybys. They reveal new insights into the processes that drive the solar wind – the constant outflow of hot, ionized gas that streams outward from the Sun and fills up the solar system – and how the solar wind couples with solar rotation. Through these flybys, the mission also has examined the dust of the coronal environment, and spotted particle acceleration events so small that they are undetectable from Earth, which is nearly 93 million miles from the Sun.
During its initial flybys, Parker studied the Sun from a distance of about 15 million miles. That is already closer to the Sun than Mercury, but the spacecraft will get even closer in the future, as it travels at more than 213,000 mph, faster than any previous spacecraft.
Details about the four main takeaways are described at the link. None of the discoveries is earth-shaking but all help scientists better understand the Sun’s inner atmosphere.
Capitalism in space: SpaceX plans to perform a six hour orbital coast test of its Falcon 9 upper stage following the release of the Dragon cargo capsule tomorrow (scrubbed today due to high winds).
This is why the first stage will land on a drone ship rather than at Kennedy.
According to SpaceX the test is at the request of “other customers”, unnamed. The article adds this speculation:
Jensen says that the coast test will be performed for unspecified “other” customers, presumably referring to the US Air Force (USAF) and other commercial customers interested in direct-to-geostationary (GEO) launch services. Direct GEO launches require rocket upper stages to perform extremely long coasts in orbit, all while fighting the hostile vacuum environment’s temperature swings and radiation belts and attempting to prevent cryogenic propellant from boiling off or freezing solid. In simple terms, it’s incredibly difficult to build a reliable, high-performance upper stage capable of remaining fully functional after 6-12+ hours in orbit.
Although SpaceX said that the test was for “other” customers, that may well have been a cryptic way to avoid indicating that one such customer might be NASA itself. NASA is in the midst of a political battle for the Europa Clipper spacecraft’s launch contract, which is currently legally obligated to launch on NASA’s SLS rocket. Said rocket will likely cost on the order of >$2 billion per launch, meaning that simply using Falcon Heavy or Delta IV Heavy could save no less than ~$1.5 billion. Incredibly, that means that simply using a commercial launch vehicle could save NASA enough money to fund an entire Curiosity-sized Mars rover or even a majority of the cost of building a dedicated Europa lander. Such a launch would demand every ounce of Falcon Heavy’s performance, including a very long orbital coast.
These speculations could all be true. SpaceX might merely be doing what it always does, testing new engineering upgrades during operational missions. It will then be able to sell its rocket’s enhanced capability to all these customers.
The new colonial movement: According to Chinese officials, China plans to launch 30 times in 2020, maintaining the same pace that they met in 2019.
Zhuang Jingguo, chief engineer of the China Aerospace Science and Technology Corporation (CASC), the country’s man space contractor, told media at the Fifth China International Commercial Aerospace Forum late last month that the state-owned enterprise will launch around 30 rockets next year.
This number is expected to include missions to Mars, the moon, test flights of new launch vehicles, and the completion of the Beidou navigation system. Commercial launch companies will further add to Chinese launch activities.
The article also provides a good overall summary of China’s present space effort, which is extensive and growing.
During an agency meeting where the new manager of NASA’s manned program officially took charge, administrator Jim Bridenstine expressed disagreement with a Trump administration estimate of $2 billion for each SLS launch.
The OMB letter used “over $2 billion” as the estimated cost of an SLS launch, arguing that is $1.5 billion more than a commercial launch. The $2 billion figure has been widely cited since then as an official cost estimate.
Bridenstine was asked about it today, and disagreed. “I do not agree with the $2 billion number. It is far less than that. I would also say the number comes way down when you buy more than one or two. I think in the end we’re going to be in the $800-900 million range.” NASA has bought only two SLS launches so far and negotiations are just starting on the third and fourth, he added. [emphasis mine]
Well that solves everything! SLS will only cost a little less than a billion per launch, not two billion. Any fool can see this is clearly competitive with the $100 million that SpaceX charges for each Falcon Heavy launch. And you’d have to do two Falcon Heavy launches to match what SLS can do in one launch. Obviously we want to buy SLS! It’s what any Washington lawmaker or bureaucrat would clearly conclude.
The article notes that NASA has only “bought two SLS launches” but fails to explain why. This is all that Congress has appropriated. NASA is negotiating with Boeing to build as many as ten more, but as far as I know, the authorization from lawmakers has not yet been given to do so.
But then, why not? We are no longer ruled by our elected officials, but by the unelected bureaucrats who live high on the hog in their plush Washington digs.
Chinese engineers have put both Chang’e-4 and Yutu-2 into dormant mode after completed their twelve lunar day on the far side of the Moon.
The article from the Chinese state-run press provides very little information, other than telling us that Yutu-2 traveled 345 meters, written in a way to imply that was the distance the rover traveled in this last lunar day. I think that is wrong, however. Based on the distances traversed during previous lunar days, and that the rover had traveled a total of 290 meters at the end of its tenth lunar day, I think this new number is the total distance traveled.
The article also does not say what the consequences will be for these two spacecraft now that the priority of their communications relay has shifted from communications to being a radio telescope.
It could be that the consequences will be minor, considering that both spacecraft are in sleep mode during the lunar nights and for high noon of the lunar day. During those periods the relay satellite could be devoted full time to radio astronomy and have no impact on the lander and rover.
Unfortunately China has not said.
Boeing has decided to delay its first unmanned demo mission of its Starliner capsule to ISS by two days, to December 19, because of launchpad issues.
The space telescope TESS, designed to look for exoplanets by imaging one hemisphere of the sky repeatedly over a full year, also successfully captured in those images the full outburst from the comet 46P/Wirtanen that occurred on September 26, 2018.
The animation created from those images is to the right.
According to Farnham, the TESS observations of comet Wirtanen were the first to capture all phases of a natural comet outburst, from beginning to end. He noted that three other previous observations came close to recording the beginning of an outburst event. Observations of a 2007 outburst from comet 17P/Holmes began late, missing several hours of the initial brightening phase of the event. In 2017, observations of an outburst from comet 29P/Schwassmann-Wachmann 1 (SW1) concluded early, due to limitations on pre-scheduled observation time. And, while observations from the UMD-led Deep Impact mission captured an outburst from comet Tempel 1 in unprecedented detail in 2005, the outburst was not natural—created instead by the mission’s impactor module. However, the current observations are the first to capture the dissipation phase in its entirety, Farnham said.
Although Wirtanen came closest to Earth on December 16, 2018, the outburst occurred earlier in its approach, beginning on September 26, 2018. The initial brightening of the outburst occurred in two distinct phases, with an hour-long flash followed by a more gradual second stage that continued to grow brighter for another 8 hours. This second stage was likely caused by the gradual spreading of comet dust from the outburst, which causes the dust cloud to reflect more sunlight overall. After reaching peak brightness, the comet faded gradually over a period of more than two weeks. Because TESS takes detailed, composite images every 30 minutes, the team was able to view each phase in exquisite detail.
The data from TESS is likely going to overwhelm the astronomy community for years.
The uncertainty of science: A new peer-reviewed paper in a major astronomy science journal suggests that dark energy might not actually exist, and that the evidence for it might simply be because the original data was biased by the Milky Way’s own movement.
What [the scientists in this new paper] found is that the best fit to the data is that the redshift of supernovae is not the same in all directions, but that it depends on the direction. This direction is aligned with the direction in which we move through the cosmic microwave background. And – most importantly – you do not need further redshift to explain the observations.
If what they say is correct, then it is unnecessary to postulate dark energy which means that the expansion of the universe might not speed up after all.
Why didn’t Perlmutter and Riess [the discoverers of dark energy] come to this conclusion? They could not, because the supernovae that they looked were skewed in direction. The ones with low redshift were in the direction of the CMB dipole; and high redshift ones away from it. With a skewed sample like this, you can’t tell if the effect you see is the same in all directions.
The link is to a blog post by a physicist in the field, commenting on the new paper. Below the fold I have embedded a video from that same physicist that does a nice job of illustrating what she wrote.
This paper does not disprove dark energy. It instead illustrates the large uncertainties involved, as well as show solid evidence that the present consensus favoring the existence of dark energy should be questioned.
But then, that’s how real science works. When the data is sketchy or thin, with many assumptions, it is essential that everyone, especially the scientists in the field, question the results. We shall see now if the physics community will do this.
Hat tip to reader Mike Nelson.
