Space Stuff and Launch Info

[mfb]

Satellite-based cellphone coverage is becoming reality. The bandwidth will be tiny, but good enough to send text messages. That's all you need e.g. in an emergency. Maybe phone calls will work, too. Satellites don't have dead spots and text messages don't need non-stop connection, so even a few of them can provide emergency services everywhere (with regulatory approval in that country). No extra hardware required, current phones already have everything that's needed.

• Lynk Global launched a few test satellites and wants to launch thousands of satellites in the future.
• BlueWalker 3 by AST SpaceMobile will launch September 7. It's massive when unfolded. After this prototype the company wants to launch about 240 (even larger) operational satellites. It's not yet clear how customers will get access to these two services - it's likely they will cooperate with local phone carriers, country by country.
• T-Mobile (US) and SpaceX announced a cooperation to use a small part of T-Mobile's spectrum on Starlink satellites. They want to start a beta test in late 2023 with the first next-generation ("v2") Starlink satellites. Here is the announcement. The same satellites can be used in other countries as well, pending approval and cooperation with some local carrier.

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A bit over three days until the launch of Artemis-1.

 

[sophiecentaur]

Satellite-based cellphone coverage is becoming reality.

That is very surprising to me. Terrestrial coverage is relatively easy, for a given available spectrum space because the service area of each base station is well defined, small and more or less permanent. Satellites would need much more directive antennae (with very good sidelobe performance) to provide that level of 'subscriber selectivity' and channel reuse.
I guess it all depends on what user bandwidth is adequate and commercially viable but there are fundamentals which will always limit the usefulness and money-making capability of such a system. I read in one link of "planned 5G coverage". That would be very surprising unless cells could be kept to their present size - multiple transmitters on each satellite?

But my intuitive 'numbers' may be way out for an accurate appreciation of the possibilities.

I loved the Steve Jobs black T shirts on the launch video. It went on far too long to hold my interest.

 

[Rive]

Satellite-based cellphone coverage is becoming reality.

That's one big stretch out there, I think. The best can be said about this would be something like 'satellite based emergency contact ability'

 

[sophiecentaur]

That's one big stretch out there, I think. The best can be said about this would be something like 'satellite based emergency contact ability'

Not exactly big bucks, though(?).

 

[Rive]

Sure makes the equipment cost of a rescue request lower, and may make many instrumental applications cheaper (remote sensors, for example: on sea or anywhere far away), but I can't see the big bucks in this either.

 

[hmmm27]

Could've used some sat coverage the other day : "lost in the woods" for an hour, or so. Not a big deal... okay, not even a small deal (the sun was out, it was daytime, and it turned out I was exactly where I thought I was), but more than a bit annoying that my cell-based compass and cell-based map showed North in two different directions.

 

[anorlunda]

The Garmin Inreach has been around for years. It uses Iridium low-earth satellites. Sailors use them out at sea. Hikers use them when trekking the wilderness. Parents use them to track their kids.

The bandwidth is low, but the value is high. Travelers use it to send a "bread crumb trail" record of their travels to a website (I think once every 10 minutes). They also send and receive SMS messages, and receive weather forecasts (especially marine forecasts for sailors). They have a SOS button to call for help. That one bit of information (SOS), paired with your location has enough value to save your life.

I used to carry an EPIRB beacon on my boat. It cost $3000, and it needed a new $1000 battery every 3 years. It was bulky and heavy. It provide zero value if there was no emergency. Inreach type devices offer much more value for much less money. They fit in your pocket. They duplicate all the EPIRB's capabilities except for the short-range homing beacon on 121.5MHz.

Here is a sample Inreach message from my email inbox back in 2017.

Going downwind for 9 days was an exhilarating experience and we managed to keep abreast of the big boys in the rally

View the location or send a reply to [redacted]: https://inreach.garmin.com/textmessage/txtmsg?extId=822b26a3-b71c-47d3-9349-7b1c1d11a1d4

[redacted] sent this message from: Lat 23.090987 Lon -82.493441

Do not reply directly to this message. This message was sent to you using the inReach two-way satellite communicator with GPS. To learn more, visit http://explore.garmin.com/inreach.

 

[mfb]

multiple transmitters on each satellite?

The satellites have phased array antennas with many (likely thousands) small transmitters.

It's not a replacement of terrestrial coverage, it's an addition for regions where building cell phone towers is not realistic, or as temporary emergency access after a catastrophe, when there is no power or the cell phone towers have been destroyed. A cell phone is everything you'll need to be in contact with others, no matter where (if approved by that country).

Sure, Iridium&co offer that level of connectivity today, but it's expensive and needs custom hardware.

 

[mfb]

NASA bought five more Crew Dragon flights (Crew-10 to Crew-14). That will cover the demand for the ISS until its retirement assuming the US maintains a long-term crew of 4 people. If e.g. Russia stops sending Soyuz crews then it is possible that NASA wants to send more.

Here is an interesting comparison:

For development of Starliner, two demo missions and 6 operational ISS crew exchange missions Boeing was awarded $4.39 or $4.49 billion (sources disagree).

For development of Crew Dragon, two demo missions and 14 operational crew exchange missions SpaceX was awarded $4.93 billion. More than twice as many flights for almost the same total price. And it's a system that is already flying routinely while Starliner still hasn't flown any astronauts.

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60% chance of acceptable weather for Artemis 1 tomorrow.

 

[mfb]

Satellite-based cellphone coverage is becoming reality.

Apple has announced emergency SOS features for the next iPhone generation. Apple has an agreement with Globalstar which operates 24 satellites in low Earth orbit. It's only for emergency signals transmitting a few bytes of data, it needs the phone oriented in a specific way, it could need a minute to work, and initially it will only cover the US and parts of Canada. But it's following the general trend: emergency communication anywhere, anytime, via satellites. In a few years we might see this working in most places.

 

[Rive]

it's a system that is already flying routinely while Starliner still hasn't flown any astronauts.

I wonder what would happen if they miss the ISS with their six paid crew missions

 

[mfb]

Firefly's second attempt to reach orbit with their Alpha rocket (630 kg to low Earth orbit) is scheduled for today 22:00 UTC, that's in 5 hours (live coverage e.g. here). It's a 4 hour launch window. The first flight in September 2021 failed due to an engine problem. They fly the same mixture of small payloads for technology demonstration, and even copies of the same satellites where the customers managed to build another one.
Edit: Scrubbed, next attempt a day layer.

ABL Space Systems aims at a maiden flight of RS1 (1350 kg to low Earth orbit) in 1-2 weeks, no fixed date yet.

Terran 1 (1250 kg to low Earth orbit), built by Relativity Space, could also make its maiden flight this month, but we don't have a launch date and it has been delayed often.

This month could more than double the number of US startups with active and successful small rockets (RocketLab and Virgin Orbit fly their rockets routinely).

Not a small rocket: The next launch opportunity for SLS (Artemis 1) is now September 23, in a launch window opening 10:47 UTC.

 

[sophiecentaur]

@mfb keep 'em coming. Much appreciated.

 

[mfb]

Engine failure during NS-23, an uncrewed suborbital flight of Blue Origin's New Shepard capsule. The capsule used its escape system and landed safely.

Video. The timestamp is set to 10 seconds before liftoff, engine failure happens at 1:04. We see about a second of extra fire that shouldn't be there before the much brighter flame from the launch escape system takes over.

Article

It's likely the booster crashed (or got destroyed in flight), but nothing specific from Blue Origin so far (this happened just 2 hours ago).

 

[berkeman]

Wow, that escape system rocket fired very quickly, which I guess is by design.

 

[mfb]

Still nothing more specific about New Shepard. We might have to wait for the results of the investigation before we hear more.

Space Launch System tanking test is ongoing, if it works well there is a chance to launch September 27 or October 2.

DART will hit Dimorphos on Monday (23:14 UTC). After billions of years of asteroids bombarding Earth, we finally strike back!
It's accompanied by a cubesat to watch the collision. NASA will provide live coverage on YouTube. We should quickly get confirmation that a collision happened, but studying the change in momentum could take months.
The spacecraft Hera is planned to reach the system in 2026 to study it in more detail.

 

[mfb]

6 hours 15 minutes until the DART impact.

DART is currently ~140,000 km away and its target Dimorphos is still too dim to be visible, so it's still navigating based on Didymos.

Live coverage will be linked here: https://www.nasa.gov/

 

[anorlunda]

The NASA FAQ on the Dart mission doesn't cover my question.

When will we get confirmed data about the magnitude of the deflection achieved? [I imagine several months from now.]

 

[mfb]

Months is what I heard, too. It's difficult to see it from Earth, we fully rely on the orbital period to change slightly which means the difference in position will accumulate over time.

The larger Didymos is a bit under 1 km in diameter.

 

[mfb]

Impact!

Last frame where it was visible fully, they had some extremely high resolution images of the impact site in the last seconds (after the picture I copied).

Images that will be studied for months, because the next time we will see it up close will be 2026.

Images from the cubesat should arrive over the next days. It's smaller and the images are less urgent so it has a much smaller bandwidth than the primary mission.

 

[mfb]

As seen from South Africa

As seen by ATLAS (Hawaii? also South Africa)

Last seconds combined in a video

 

[sophiecentaur]

As seen from South Africa

As seen by ATLAS (Hawaii?)

Last seconds combined in a video

That clip from ATLAS will be used in every submission for project funding for years. It looks just like a Zap moment - straight to the hearts of the committee.
The movie suggests that the whole target was broken up. Presumably the cube sat will show the details..

 

[mfb]

It shouldn't have enough energy to break it up, and I don't see how you would get such a pattern from a breakup either. It's clearly directional, away from the impact on the side of that impact.

Some early images from the Italian cubesat

 

[pinball1970]

This is nice, the detail on the comet before the impact is fantastic.

 

[sophiecentaur]

I don't see how you would get such a pattern from a breakup either.

Puzzling. The cloud seems just to disperse and disappear, almost as if it turns to gas. Or perhaps it's an artefact of the image processing and a hard black level being set. Astrophotographers get up to tricks like that to make features more obvious.

 

[gleem]

DART had the energy equivalent of about 3 tonnes of TNT. It seemed to me that there was a lot of debris on the asteroid's surface which is held loosely on the smallish Dimorphos. So the cloud is just this material being kicked off?

 

[hutchphd]

 

[mfb]

DART had the energy equivalent of about 3 tonnes of TNT. It seemed to me that there was a lot of debris on the asteroid's surface which is held loosely on the smallish Dimorphos. So the cloud is just this material being kicked off?

Sure. Different pieces have a different velocity so the debris cloud spread out quickly.

 

[sophiecentaur]

So the cloud is just this material being kicked off?

It's the momentum of the 'cloud' going in one direction that changes the momentum of the asteroid in another direction. It's important that the mass and composition of the cloud is right (fast and small bits) to avoid any of it being potentially a collision hazard with Earth. (mV = -Mv symbols self explanatory)

 

[Baluncore]

So the cloud is just this material being kicked off?

On collision, the impactor and part of the target were vaporised in the flash.
The incandescent gas released was visible, moving outwards at a thermal velocity, until it cooled and condensed.

 

[.Scott]

Here is what I see from the Atlas telescope shot:
1) The collision occurs and a relatively small amount (compared to the full asteroid) of material is ejected.
2) The ejected material spreads out and quickly become too dispersed to track.
3) On the Atlas video, it appears the collision occurred at the 8 or 9 o'clock position on the asteroid and not on its perimeter as seen from the telescope. In other words, it hit either on the earth-facing side or the opposite side and not that close to the boundary separating the sides.
4) A cloud of loose material remains around the asteroid - causing it to appear about twice its original diameter. The cloud did not disperse as quickly as it formed, so there may be a substantial amount of material that was left orbiting the asteroid.
5) Not surprisingly, no change in the asteroids trajectory can be discerned in the video.

 

[sophiecentaur]

The collision occurs and a relatively small amount (compared to the full asteroid) of material is ejected.

I was thinking about the frequent threads about the shapes of craters from meteorite impact. The argument is that they tend to be circular because the biggest effect is from the 'explosion' due to the kinetic energy, rather than the momentum changes. But perhaps the 6.6km/s closing speed of dart would not be as high as for a meteorite (about ten times that value, max).

 

[mfb]

NASA, SpaceX and the Polaris program collaborate to study a possible Hubble reboost mission with Dragon. Maybe even a reboost and service mission. Such a mission can extend Hubble's lifetime by years.

The study is expected to take 6 months. This could become the second flight of the Polaris program. The first one will include an EVA, which would make a lot of sense if the second mission wants to exchange some ageing components of Hubble. A reboost isn't helping much if the spacecraft fails a few months later.

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Firefly is at the next launch attempt.
Currently holding for reasons I didn't catch, but the rocket is fueled and they have about 2 hours left in their launch window.

Edit: Reached engine ignition but aborted before takeoff. Next attempt tomorrow.
Edit2: Success! Another startup has made it to orbit. Video quality is pretty poor, unfortunately.

 

[mfb]

45 minutes until the launch of Crew-5. SpaceX livestream.
Anna Kikina will be the first Russian astronaut to fly on Dragon, and first Russian astronaut to fly on a US spacecraft that's not the Shuttle.

8th flight of Crew Dragon, second flight of this capsule, first flight of the booster which has gotten rare.

Edit: Successful launch, Dragon is in space. Based on an unlucky orbital alignment they'll need 29 hours to reach the ISS.

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Atlas V has 20 launches left. It uses Russian engines so that number is known precisely, and all launches have been booked. Someone noted how the types of launches align with Tolkien's 20 rings:

Three rings for the Elven-kings under the sky,
Seven for the Dwarf-lords in their halls of stone,
Nine for mortal men doomed to die,
One for the Dark Lord on his dark throne;
In the Land of Mordor where the shadows lie.

Three launches will be US government satellites.
Seven launches will be Starliner capsules, where the rocket is shorter than usual.
Nine launches will be for Project Kuiper (Amazon).
That makes Viasat, the customer for the last launch, the Dark Lord?

 

[pinball1970]

@Astranut