Space News thread

[Takeovers]

So what's the satellite going to do?

It is a quite heavy com sat that will operate in GEO, geostationary orbit. The rocket placed it in a transfer orbit and the satellite will reach GEO with on board propulsion.

Long March 5 is a quite heavy lifter in its larger configuration. It will lift the components for the chines space station and in a smaller configuration lift crew capsules.

[Takeovers]

China has built the largest single dish radiotelescope in the world and is now offering it to scientists all over the world to use it.

Gigantic Chinese telescope opens to astronomers worldwide



The world’s largest single-dish radio observatory is preparing to open to astronomers around the world, ushering in an era of exquisitely sensitive observations that could help in the hunt for gravitational waves and probe the mysterious fleeting blasts of radiation known as fast radio bursts.


The Five-hundred-meter Aperture Spherical Radio Telescope (FAST) in southern China has just passed a series of technical and performance assessments, and the Chinese government is expected to give the observatory the final green light to begin full operations at a review meeting scheduled for next month. “We do not see any roadblocks for the remaining transition,” says Di Li, the chief scientist of FAST. “I feel both excited and relieved.”


The complex project has not been without challenges — it has a radical design and initially struggled to attract staff, in part because of its remote location. But the pay-off for science will be immense. FAST will collect radio waves from an area twice the size of the next-largest single-dish telescope, the Arecibo Observatory in Puerto Rico.


The Chinese observatory’s massive size means that it can detect extremely faint radio-wave whispers from an array of sources across the Universe, such as the spinning cores of dead stars, known as pulsars, and hydrogen in distant galaxies. It will also explore a frontier in radioastronomy — using radio waves to locate exoplanets, which may harbour extraterrestrial life.


Since testing began in 2016, only Chinese scientists have been able to lead projects studying the telescope’s preliminary data. But now, observation time will be accessible to researchers from around the world, says Zhiqiang Shen, director of the Shanghai Astronomical Observatory and co-chair of the Chinese Academy of Sciences’ FAST supervisory committee.


“I’m super excited to be able to use the telescope,” says Maura McLaughlin, a radioastronomer at West Virginia University in Morgantown, who wants to use FAST to study pulsars, including hunting for them in galaxies outside the Milky Way, that are too faint to see with current telescopes.


During the testing phase, the telescope discovered more than 100 pulsars.


Eye in the sky
The 1.2-billion-yuan (US$171-million) telescope, also known as Tianyan or ‘Eye of Heaven’, took half a decade to build in the remote Dawodang depression in the Guizhou province of southwest China. Its 500-metre-wide dish is made up of around 4,400 individual aluminium panels that more than 2,000 mechanical winches tilt and manoeuvre to focus on different areas of the sky. Although it sees less of the sky than some other cutting-edge radio telescopes, and has lower resolution than multidish arrays, FAST’s size makes it uniquely sensitive, says Li.


In August and September, the instrument detected hundreds of bursts from a repeating fast radio burst (FRB) source known as 121102. Many of these bursts were too faint to be perceived by other telescopes, says Li. “This is very exciting news,” says Yunfan Gerry Zhang, who studies FRBs at the University of California, Berkeley. No one knows what causes the mysterious bursts, but “the more pulses we have, the more we can learn about them”, he says.


FAST examines only a tiny fraction of the sky at any one time, making it unlikely to discover many new FRBs, which are fleeting and occur in seemingly random locations. But the telescope’s “impressive sensitivity” will be useful for following up on sources in detail, says Laura Spitler, an astronomer at the Max Planck Institute for Radio Astronomy in Bonn, Germany. Repeat observations could allow scientists to learn about the environment from which an FRB emerged, and to determine whether the blasts vary in energy or recur with any set pattern.


FAST will also boost the efforts of an international collaboration that is trying to spot ripples in space-time as they sweep through the Galaxy, says McLaughlin. The International Pulsar Timing Array is using radio telescopes around the world to monitor the regular emissions from pulsars, looking for distortions that would reveal the passing of these low-frequency gravitational waves. By the 2030s, FAST should have racked up enough sensitive measurements to study individual sources of such waves, such as collisions of supermassive black holes, says McLaughlin. “That’s where FAST is really going to shine,” she says.


Li says that he is particularly excited about the study of planets outside the Solar System. No exoplanets have yet been conclusively detected by their radio emissions, but FAST’s ability to spot faint, polarized waves might allow it to find the first examples, says Li. Polarized radio signals might come from planets with magnetic fields that, if similar to the one on Earth, could protect potential sources of life against radiation and keep the planets’ atmospheres attached.


Identifying a planet in FAST’s wide beam is a challenge, because they are so faint and small. But Li’s team wants to boost the telescope’s performance by adding 36 dishes, each 5 metres wide. Although the dishes are relatively cheap, off-the-shelf products, together they will improve FAST’s spatial resolution by 100 times, he says.


Li hopes that FAST’s telescope operations will soon move from near the remote site to a $23-million data-processing centre being built in the city of Guiyang. He expects that the move to a major city will help attract more technical and engineering staff.


Now the team’s biggest hurdle is working out how to store and process the enormous amount of data that the telescope will churn out. The team are negotiating with the Chinese government to get additional funding for more data storage. “A successful review will definitely help,” he says.

[OhOh]

tilt and manoeuvre to focus on different areas of the sky

The telescope's "beam" can be "steered" to a particular point, rather than just vertically upwards then?

[Luigi]

^ It has an 'active surface', the individual panels can be tilted via computer. The feed antenna is also moved to receive data from different directions.

[Takeovers]

Steering is possible. Unfortunately only within limitations. It would be much better to build a telescope that size in space. Ideally behind the moon in EM-L2 where no radiation from Earth can reach. But that won't happen any time soon.

There are other designs. Not with the same sensitivity but higher resolution. Both designs have their own strengths and weaknesses.

Very Large Array - Wikipedia

[OhOh]

Thanks, both of you.

[Takeovers]

We are getting closer to flying astronauts to the ISS with american spacecraft again. SpaceX is preparing for the last critical test before a flight with crew. The in flight abort test scheduled for January 18. Launch window begins 8:00 ET, 13:00 UTC.

A capsule will fly and then simulate an error at the most critical part of the flight, when the atmospheric drag is highest. That happens at an altitude of 17km. The atmosphere is quite thin there already but the speed is getting high. At that time the rocket shuts down and the Dragon capsule fires its abort engines to get the capsule safely away from the rocket.

Here the thread on the NSF forum on the topic. Jump to the end of the thread for latest info.


SpaceX F9 : Crew Dragon In-Flight Abort Test : NET Jan. 18, 2020 : Updates



The rocket on the pad before doing a test fire as last health check for the vehicle. The fire has been successfully completed. After that the rocket goes back to the hangar to have the Dragon capsule attached.

If this test is successful NASA will study the results for a few month and then probably approve a manned flight to the ISS in the first half of this year.

[OhOh]

doing a test fire as last health check for the vehicle. The fire has been successfully completed

Do all rockets have the check firing, are returned to the capsule/load fitting shop and then using the same refilled rocket head for the Moon/Mars/Heart of the Sun?

[Takeovers]

Do all rockets have the check firing, are returned to the capsule/load fitting shop

No, that's only SpaceX. Others do static fires when developing new designs but not in operation.

They did integrate the payload before test fire. But then the Amos-6 incident blew up the payload along with the rocket and pad. Now they test the rocket and then integrate the payload. For their own payload, the Starlink sats, they are now back to integrating payload to speed up the process. For this year they are planning to launch Starlink sats twice every month, 24 this year in addition to launches for external customers. They need to streamline the process to be able to fly that frequently.

BTW NASA is full of praise for the results of the incident investigation. A lot was learned about the behaviour of COPVs (Composite overwrapped pressure vessels). Insurance companies were also pleased with the thoroughness and the incident did not raise insurance premiums much for that reason.

[OhOh]

Thanks.

[Takeovers]

Abort test cancelled for today due to bad weather in the landing area. Hopefully better tomorrow.

Astronauts Bob Behnken, left, and Doug Hurley. They wear the Spacex spacesuits. They did enter and leave the Dragon capsule like they would if they did fly. On board suits only, not for use in open space. They are the NASA astronauts who will make the first flight on a Dragon capsule to the ISS later this year. Possibly already in April.

[Bettyboo]

Gotta say, that big Chinese wok is pretty impressive.

[OhOh]

^^

Doug Hurley looks a little "mature". Are the Spacex physical requirements any different than say NASA, Roscosmos, CNSA requirements?

[harrybarracuda]

Gotta say, that big Chinese wok is pretty impressive.

Like everything else the chinkies do, ripped off from someone else.

[Takeovers]

Are the Spacex physical requirements any different than say NASA, Roscosmos, CNSA requirements?

Conditions in Soyuz are much harsher. Especially on landing, launch with liquid propellant engines is OK. Boeing Starliner and SpaceX Dragon should be quite comparable.

On launch the Shuttle was shaking quite violently and so will SLS. Both caused by the big solid boosters.

[Takeovers]

Like everything else the chinkies do, ripped off from someone else.

You are not very fair to them. Technical solutions are frequently similar, that's in their nature. The chinese dish is quite advanced compared to Arecibo.

[harrybarracuda]

You are not very fair to them. Technical solutions are frequently similar, that's in their nature. The chinese dish is quite advanced compared to Arecibo.

That's because it's almost 50 years older and the chinkies have had loads of other technology to steal since it was built.

[OhOh]

ripped off

The Chinese "beam" appears to be "steerable", are the previous telescopes similar?

[Takeovers]

The Chinese "beam" appears to be "steerable", are the previous telescopes similar?

Yes, to a lesser extent. The receiver can be moved by the cables it hangs on. Very limited ability to steer is the big disadvantage of large ground based dishes.

[harrybarracuda]

Yes, to a lesser extent. The receiver can be moved by the cables it hangs on. Very limited ability to steer is the big disadvantage of large ground based dishes.

I was at Arecibo a couple of years ago.

You had to turn off everything, even Bluetooth, at a distance, such is the sensitivity of the equipment.

An amazing sight.

[Takeovers]

You had to turn off everything, even Bluetooth, at a distance, such is the sensitivity of the equipment.

That's the advantage of the large dishes.

I wish we would build a dish that size in space. The sensitivity plus fully steerable. Would have to be in EM-L2 to be shielded from Earth radiation.



Wouldn't come cheap but should be in the range of the powerful but absurdly expensive James Webb telescope.

[Takeovers]

Launch of the flight abort Dragon keeps slipping a bit but should happen today, hopefully 2 hours from now. Launch weather is fine, sea at the landing site still somewhat rough but should be OK too.

NASA TV webcast.

NASA should have a chase plane out near the landing site and get us some amazing photos.

NASA Television | NASA

SpaceX webcast. Probably coverage from inside Dragon.

CREW DRAGON LAUNCH ESCAPE DEMONSTRATION | SpaceX

[Dragonfly]

nice, thanks

[harrybarracuda]

I bet Christina McAuliffe's family are watching with some regret.

[Takeovers]

Brilliant coverage again.

Test seems to be flawless. Dragon touched down in the Atlantic.

BTW for the first Dragon 2 flight, the unmanned Demo 1 mission, NASA and SpaceX received an Emmy award for the coverage.