SpaceX (general discussion)

[sferrin]

I would be surprised if it's doing anything more than up and down and maybe some low velocity horizontal translations. Given it's only supposed to go a few kms up I don't see how they could do any of this:

" - Low viscosity Supersonic pitch-up and boosted slowdown (Mars - simulated on the upper atmosphere by gaining speed - horizontal)
- High viscosity slowdown + pitch-up and boosted recovery (earth)"

 

[TomcatViP]

IN first case they have to be high and glide down at high speed/low slope to simulate the condition of Martian reentry

In the second they just need to shoot the thing high enough to see if their new reentry techniques is manageable.

The low cost rugged hopper allow them to have multiple challenging test in various configuration. Since the lander won't have a dedicated capsule (in my understanding), they have to make sure that they will be able to initiate their reentry manoeuvre (fall down horizontally, pitch up then boosted recovery) in various case of figure (landing after an aborted TO/ landing after an abridged orbital flight etc). The fuel mass fraction and volume fluctuation for such a massive vehicle would well need a dedicated test bird IMO.

I think that's what it is

 

[Flyaway]

Via NSF the BFH has been taken apart into two parts again and the dummy engines removed.

 

[Dragon029]

Not reentry by itself but the dynamic maneoevres that follow it. Sorry if that was not immediately clear.

To be specific, this is what I had in mind:

- Low viscosity Supersonic pitch-up and boosted slowdown (Mars - simulated on the upper atmosphere by gaining speed - horizontal)
- High viscosity slowdown + pitch-up and boosted recovery (earth)

It's very unlikely; they have no dynamic aerodynamic control surfaces on the Starhopper, plus they've only sought / been given approval to fly up to 16,000ft with this vehicle.

More importantly, it's been confirmed already that they have a full scale test vehicle being built in LA that will be conducting re-entry testing (and in turn, things like supersonic or high subsonic pitching manoeuvres).

Via NSF the BFH has been taken apart into two parts again and the dummy engines removed.

Sounds like they're about to install the new bulkheads.

 

[TomcatViP]

It's very unlikely; they have no dynamic aerodynamic control surfaces on the Starhopper, plus they've only sought / been given approval to fly up to 16,000ft with this vehicle.

More importantly, it's been confirmed already that they have a full scale test vehicle being built in LA that will be conducting re-entry testing (and in turn, things like supersonic or high subsonic pitching manoeuvres).

Wasn't aware of that last point. Thank you.
The ctrl surfaces on the fial design are there mainly for stability. I doubt that they will perform the pitch-up by themselves.

 

[antigravite]

It's very unlikely; they have no dynamic aerodynamic control surfaces on the Starhopper, plus they've only sought / been given approval to fly up to 16,000ft with this vehicle.

More importantly, it's been confirmed already that they have a full scale test vehicle being built in LA that will be conducting re-entry testing (and in turn, things like supersonic or high subsonic pitching manoeuvres).

Wasn't aware of that last point. Thank you.
The ctrl surfaces on the fial design are there mainly for stability. I doubt that they will perform the pitch-up by themselves.

MDD's (PhantomWorks / Bill Gaubatz) DC-X didn't have flaps either in the 1990s when it demonstrated VT/VL. (As did the manned LLRV in the Apollo era to simulate / flight test moon landings).

A.

 

[Dragon029]

It's very unlikely; they have no dynamic aerodynamic control surfaces on the Starhopper, plus they've only sought / been given approval to fly up to 16,000ft with this vehicle.

More importantly, it's been confirmed already that they have a full scale test vehicle being built in LA that will be conducting re-entry testing (and in turn, things like supersonic or high subsonic pitching manoeuvres).

Wasn't aware of that last point. Thank you.
The ctrl surfaces on the fial design are there mainly for stability. I doubt that they will perform the pitch-up by themselves.

They play a major part in the pitch-up; when it comes time to perform the manoeuvre the front canards reduce their dihedral to shift the centre of pressure forward of the CG. You can see from about the 50 second mark of this video (which as a reminder is a full physics simulation of the landing technique, not an artist's concept) that the front fins are used to perform the pitch manoeuvre, and that the engines don't ignite until it's already only ~10 degrees off vertical:

https://www.youtube.com/watch?v=LQTnWEHl5qU

Also here's the tweet about the "orbital prototype" being expected to finish production in around June: https://twitter.com/elonmusk/status/1083575233423003648

MDD's (PhantomWorks / Bill Gaubatz) DC-X didn't have flaps either in the 1990s when it demonstrated VT/VL. (As did the manned LLRV in the Apollo era to simulate / flight test moon landings).

A.

The DC-X was designed to re-enter nose-first rather than side/belly-first like the Starship; it's also my understanding that the DC-X would have utilised control flaps for aerodynamic control during initial re-entry (the rocket was only tested to 2500m however).

If Starship had no fins I'm quite positive that it too would be able to perform a flip just using thrusters, but because they want to achieve this unstable belly-first re-entry profile (which more or less is required for landing on Mars with a large payload), they more or less need fins.

 

[TomcatViP]

Yes I do agree. I have seen this video too also. And this is why I think that the test vehicle in Boca Chica would be of great help in validating the range of configuration suitable to pass this manoeuvre. Since their landing vehicle is huge there is plenty of varying case to test.

Thank you for the Twitter link.

 

[Flyaway]

In blow to Los Angeles, SpaceX is moving its Mars spaceship and booster work to Texas

In a reversal of a deal local officials touted as a win for Los Angeles tech, SpaceX will no longer be developing and building its Mars spaceship and rocket booster system at the Port of Los Angeles. Instead, the work will be done in South Texas.
“This decision does not impact our current manufacture, design, and launch operations in Hawthorne and Vandenberg Air Force Base in California,” a company spokesperson said in a statement Wednesday. “Additionally, SpaceX will continue recovery operations of our reusable Falcon rockets and Dragon spacecraft at the Port of Los Angeles.”

 

[Dragon029]

That article was written due to a communication error from SpaceX; basically nothing's changing:

https://twitter.com/elonmusk/status/1085679367374524417

If I had to guess, the miscommunication was probably SpaceX saying that development would be moving to Boca Chica, but in the sense that SpaceX will only (as has been planned for years) be looking to launch Starship from Texas and Florida, as Vandenberg doesn't have the facilities to support the new rocket.

 

[Tuna]

It's very unlikely; they have no dynamic aerodynamic control surfaces on the Starhopper, plus they've only sought / been given approval to fly up to 16,000ft with this vehicle.

And just as an additional note: In previous testing with the grasshopper and the F9R, SpaceX has always gotten approval for ~3 times the altitude they actually intend to fly at, so that in loss of control situations they have more room to try and fix things before they have to hit self-destruct.

Asking for 16000ft probably means they actually intend to fly up to 5-6000ft or so.

 

[Flyaway]

SpaceX separates Starship prototype’s nose and tail to install giant propellant tanks

After a handful of days as an impressive monolith stood along the coastal wetlands of Texas, SpaceX technicians have once again separated the nose and tail sections of the first Starship prototype to allow additional integration and assembly work to continue. The craft’s three Raptors were also removed and stored nearby, shown to be barebones facsimiles standing in for flightworthy hardware that could arrive in the next month or two.

Up next, three or four propellant tank domes – currently being assembled and welded together on-site – will likely be installed inside the steel hull of the giant Starship prototype’s aft barrel section. Known as bulkheads, the installation of those tank domes will bring SpaceX one step closer to performing hop tests of the simultaneously bizarre, confusing, and beautiful craft.

 

[Dragon029]

One of the bulkheads is in, though there'll be more work to do (cleaning, putting ports in, etc) before the other bulkhead is welded in as well.

 

[Flyaway]

SpaceX fits Starship prototype with tank bulkheads as hop test pad progresses

SpaceX workers have begun installing fuel and oxidizer tank bulkheads inside the first BFS/Starship prototype at the same time as the vehicle’s nearby ‘launch’ facility continues to sprout important infrastructure and slowly morph from a giant pile of dirt into something capable of supporting rocket hop tests.

Several observable characteristics of this project still do not immediately make sense but whatever the direction SpaceX is moving in, engineers and technicians are working around the clock to ensure that progress is steady.

 

[Flyaway]

Elon Musk: Why I'm Building the Starship out of Stainless Steel

Musk tweeted in January that the rocket formerly known as BFR would be built of stainless rather than carbon fiber. In this exclusive interview, he tells PM Editor in Chief Ryan D'Agostino why.

On the windward side, what I want to do is have the first-ever regenerative heat shield. A double-walled stainless shell—like a stainless-steel sandwich, essentially, with two layers. You just need, essentially, two layers that are joined with stringers. You flow either fuel or water in between the sandwich layer, and then you have micro-perforations on the outside—very tiny perforations—and you essentially bleed water, or you could bleed fuel, through the micro-perforations on the outside. You wouldn’t see them unless you got up close. But you use transpiration cooling to cool the windward side of the rocket. So the whole thing will still look fully chrome, like this cocktail shaker in front of us. But one side will be double-walled and that serves a double purpose, which is to stiffen the structure of the vehicle so it does not suffer from the fate of the Atlas. You have a heat shield that serves double duty as structure.

 

[Dragon029]

Unfortunately a storm has toppled the (separated) top-half of Starhopper, damaging it quite a bit. On the plus side it's not as important as the bottom half of the rocket, but this will obviously set things back probably a couple of weeks, unless they decide to omit certain test objectives and just carry on with a half-sized Starhopper.

Photos courtesy of bocachicagal at the NASA Spaceflight Forum.

Edit: Also a couple of tweets from Elon about it:

https://twitter.com/elonmusk/status/1088088320767217664

I just heard. 50 mph winds broke the mooring blocks late last night & fairing was blown over. Will take a few weeks to repair.

https://twitter.com/elonmusk/status/1088102778826764289

Actual tanks are fine

Talk about an omen:
https://twitter.com/elonmusk/status/1081575156990894082

How long until the first hopper test. What do you think?

Aiming for 4 weeks, which probably means 8 weeks, due to unforeseen issues

 

[Flyaway]

The nosecone of the starship hopper has blown over in strong winds & been damaged. Mr Musk states it will take a few weeks to repair. However, the business end of the hopper is fine.

 

[sferrin]

NASA would be folding up the tent by now.

 

[TomS]

NASA would be folding up the tent by now.

Or they wouldn't have built it out in the open in the first place...

 

[Dragon029]

It's definitely a risk doing this kind of work out in the open, but at least it's ultimately just relatively cheap steel and can be built again from scratch in a couple of weeks.

 

[sferrin]

NASA would be folding up the tent by now.

Or they wouldn't have built it out in the open in the first place...

Because they would have built a billion dollar building first.

 

[sferrin]

It's definitely a risk doing this kind of work out in the open, but at least it's ultimately just relatively cheap steel and can be built again from scratch in a couple of weeks.

Or hammered out.

 

[flanker]

DM-1 has completed static fire test on the same day as FH did it one year ago.

 

[Flyaway]

SpaceX CEO Elon Musk teases white-hot Starship heat shield testing in video

SpaceX CEO Elon Musk has shared a video showing what looks to be the early stages of testing for Starship’s (BFS) unprecedented metallic heat shield, recently described as a double-layered steel sandwich that will be regeneratively cooled by cryogenic liquid methane.

 

[sferrin]

"unprecedented"? IIRC The X-20 Dyna-Soar also used active cooling of a hot structure.

 

[Moose]

"unprecedented"? IIRC The X-20 Dyna-Soar also used active cooling of a hot structure.

Bell's X-20 concept did, Boeing's winning concept did not. But both were definitely metallic heat shields conceived long before Elon's Starship.

 

[Flyaway]

SpaceX achieves testing milestone under the shadow of a government shutdown

If it comes to that, NASA and SpaceX have what they need to move ahead with the flight. As others, including Marina Koren in The Atlantic, have pointed out, a government shutdown doesn’t necessarily mean that the launch will be pushed back. While 95 percent of NASA personnel are furloughed right now, there are still NASA employees working without pay on the Crew Dragon mission, doing the necessary reviews and meetings to keep the program on track.

However, SpaceX is in the clear here, too. Certain types of launches for the government do not require FAA licenses, depending on their contracts. This particular mission falls into that category because it is being used to determine if the Crew Dragon is qualified for flight. According to SpaceX’s Commercial Crew contract with NASA, the Crew Dragon’s first flight is considered a “pre-certification mission,” and therefore, it does not need an FAA license. Once it is certified, all future Crew Dragon flights will need an FAA license. For now, NASA will handle the licensing.

 

[Flyaway]

SpaceX Falcon 9 booster spied on highway as triple-satellite launch moves right

A SpaceX Falcon 9 booster was spotted heading north from the company’s Hawthorne, California factory on January 22nd, signifying a likely shipment of the flight-proven rocket that will help launch Canada’s trio of Radarsat Constellation Mission satellites.

Delayed from mid-February to early March 2019 after an unplanned landing anomaly damaged the Falcon 9 originally assigned to the mission, the shipment of a different booster to Vandenberg Air Force Base (VAFB) helps to narrow down the rocket now likeliest to launch the Canadian Space Agency’s (CSA) radar satellite constellation.[/url]

 

[Flyaway]

SpaceX Video Shows Off Crew Dragon Access Arm for Astronauts

SpaceX just unveiled the view astronauts will see when they board a Crew Dragon spaceship.
A new video from SpaceX, unveiled via Twitter Friday (Jan. 25), offers a glimpse of what NASA astronauts Bob Behnken and Doug Hurley will see later this year when they board a Crew Dragon for its first-ever crewed spaceflight. The video shows SpaceX's sleek access arm — the hallway-like bridge that astronauts will use to board the craft — at Launch Pad 39A of NASA's Kennedy Space Center in Cape Canaveral, Florida.

 

[gtg947h]

NASA would be folding up the tent by now.

Or they wouldn't have built it out in the open in the first place...

Because they would have built a billion dollar building first.

NASA would still be doing "risk reduction studies" for another 10 years, because their approach would be "we're going to build the final design once, and it has to work perfectly on the very first try".
There's still a lot of programmatic risk and all that, but I'm going to laugh if they get this BFR/Starship/whatever it's called next year flying payloads before the SLS does anything useful.

 

[Flyaway]

SpaceX’s next Falcon Heavy launch may feature record-breaking center core landing

One such filing related to the first operational Falcon Heavy launch has revealed a fairly impressive statistic: comprised of three first stage boosters, SpaceX indicated that Falcon Heavy’s center core will attempt to land on drone ship Of Course I Still Love You (OCISLY) nearly 1000 km (600 mi) away from its launch site, easily smashing the record for the greatest distance traveled by a Falcon booster in flight.

 

[fredymac]

This fairing catching business is tricky.

https://www.youtube.com/watch?v=xPeFbEbxPKQ

 

[TomcatViP]

[...]
Robust Attach Point:Rugged mount point with quadruple shear joint ensures torsional strength
Lock Indicator Window:For added safety, a lock indicator window on the side of the hook gives the ground crew an easy visual signal that the hook is locked.
[...]
Onboard Weighing System Option:Know the exact weight of your load! Our pin load cell replaces the attach bolt, eliminating extra linkage.
Optional Remote Hook Electrical Release Kit:An optional Electric Remote Hook Release Kit is available, giving you the ability to release loads on the remote hook from the [deck].

But too much fun kills the fun, I guess.

By letting the fairing fall through the ship aero wake, it will kill the floating rebound effect. Falling from 10 or 20m in the net won't damage the fairing or tears the net (the latter will just need an appropriate tensioning strength - or just use an airbag placed under the net).

 

[Orionblamblam]

Robust Attach Point:Rugged mount point with quadruple shear joint ensures torsional strength

I wonder if it might be easier to simply lay down a few good strips of double-sided carpet tape on the sides of the fairings. Might not latch onto the net as positively as a mechanical latch, but it'd be simple and cheap.

 

[Dragon029]

I think what he's proposing is a mechanism to detach the fairing from its chute while (eg) 50ft over the net, so that they can avoid dealing with turbulent flow over the ship interfering with the glide path of the chute / fairing.

 

[Flyaway]

Two drone overflight videos from the 31.01.2019 of the Big Falcon Hopper & associated areas.

https://www.youtube.com/watch?v=7_4SmrPypTU

https://www.youtube.com/watch?v=iA17KwTeqs0

 

[sferrin]

Hmm. Wonder if they still plan on using the big stainless nose fairing for these tests.

 

[Moose]

Hmm. Wonder if they still plan on using the big stainless nose fairing for these tests.

Some NSF talk that they may proceed to early hops without the nose in order to get things started, but it is still expected to reappear.

 

[Flyaway]

In new Starship details, Musk reveals a more practical approach

On Thursday night, SpaceX founder Elon Musk shared photos of Raptor rocket engines that recently left the company's factory in Hawthorne, Calif., headed out to be tested at its facility near McGregor, Texas. "Preparing to fire the Starship Raptor engine," he said by way of a caption on Twitter.

In his series of tweets Thursday night, Musk shared other details that indicate he is intent on getting Starship flying as soon as possible. For example, initial versions of the Super Heavy rocket will likely fly with fewer than 31 engines, and the launch system's reaction control thrusters will have a simpler design.

These moves indicate that SpaceX and Musk are reacting to external pressures, particularly of a financial nature. Aside from the Japanese investor, it has not revealed any customers for Super Heavy and Starship, so the company is pressing ahead with a build-it-and-they-will-come approach to users. To accomplish this, however, it must cut costs elsewhere, as evidenced by the 10 percent reduction in workforce in January.

 

[TomcatViP]

@Dragon029: Thank you for deciphering my cryptic posting ;D

And to all other, sorry for the image being in such a big format.