The thread for space cadets!

[Thorgalaeg]

The EU is in large part reliant on the US for defense. While they recognize that potentially losing access to GPS in various scenarios was a significant disadvantage that they had to change that, it is probably not a sufficient reason to continually upgrade the constellation to be cutting edge forever. The US on the other hand has this massive obsession with their military and so will always upgrade their constellation to maintain technological parity, if not outright supremacy. I just don't see that same level of military commitment in Europe.

I also feel (and will be happy if I'm wrong) that huge, multinational space projects are harder for the Europeans to pull off than they are for the US due to the need to balance all of the national industrial concerns/desires of the individual nation states. European space projects can get pretty messy with basically France and Germany fighting each other over who gets to build what with all the other countries in the Union trying to elbow their way into programs. You can see this in the Ariane program where time and again balancing national industrial concerns have compromised the design from a cost-optimization perspective. That Arianespace has been so successful had as much to do with US withdrawal from the market and collapsing Russian quality assurance as it does with the technical or cost prowess of the Ariane rockets themselves. Their rockets are good but they are expensive and are ill-suited for the potential dawn of re-usable rocket fleets sweeping the market.

I do think Galileo will be properly maintained, I am just less sure that Europe will push through the same kind of major upgrades that the US has and is continuing to do for GPS.

So you think we europeans are a mess. That was not very nice.

You are not too wrong though...

 

[warpus]

What sort of clock issues does Galileo have?

 

[uppi]

I don't think Andorra will ever have a system though I wouldn't be surprised if Luxembourg puts up a system given how big of a player they are in the space industry. (totally serious)

Why would they do that when they're part of Galileo?

What sort of clock issues does Galileo have?

Some of the clocks in the operational satellites have failed. As they were launched with spare clocks, this hasn't affected operations so far, but this might be a systemic error that might lead to the rest of the clocks to fail much earlier than anticipated. I think it has also led to a delay in launching more satellites, because they had to investigate this issue

 

[hobbsyoyo]

So you think we europeans are a mess. That was not very nice.

You are not too wrong though...

Meh, I was mostly talking specifically about GNSS services. There are some unique factors that make that particular program less apt to be massively upgraded over time. Namely the huge cost and limited non-military utility of said upgrades. In particular, with so many other networks out there, you can actually increase your accuracy by using multiple networks simultaneously. This further undercuts the non-military utility of major upgrades. That, coupled with a lack of strong military impetus from within the EU for enhanced military capabilities just make it unlikely IMHO.

On the rocket front - Europe has made a lot of smart choices and have a good track record with commercial launches. On the other hand, right now SpaceX and BO are spending a ton of money figuring out what does and does not work. Europe could wait it out and just pick the best path forward and save a lot of R&D cash. Alternatively, SpaceX and BO might spend a ton of money on these re-use projects only to find out that it's a fundamentally flawed idea. In which case Europe will be in a very favorable position.

In other civil and commercial space projects, Europe is and will remain a world leader.

Why would they do that when they're part of Galileo?

I don't think Luxembourg would build the network for their own use - rather if there is a business case to be made selling GNSS services then they would be the ones to find and exploit that business case. I don't think it likely - just that I wouldn't be surprised if it came to pass. That said with so many networks basically free to use I don't see any business case in it.

I mean I guess they get some of the revenues from the higher-accuracy services that are sold. I'm just saying if there was a business case for going it alone, they would be the ones to do it. Not that they actually would, just that they probably could.

What sort of clock issues does Galileo have?

They use two different types of clocks, two rubidium and two hydrogen maser clocks. The rubidium clocks have a faulty component that shorts out and disables the unit. The hydrogen maser clocks have undisclosed problems that require them to be closely monitored.

It's all highly proprietary so I doubt we'll hear more explicit details.
https://phys.org/news/2017-07-europe-galileo-satnav-problems-clocks.html

 

[hobbsyoyo]

Block 5 on the pad:

• New grid fins
• New landing legs that can stow themselves
• New bolted octaweb
• Improved thermal protection system vehicle-wide
• Uprated engines
• Slightly bigger, recoverable fairing
• Unpainted interstage
• 10 flight re-use without teardown

They are only expecting to build about 30-50 of these vehicles and launch the fleet around 300 times. The Texas launch site is being re-focused on BFR launches and will not host Falcon. The second stage will also be upgraded for re-use incrementally.

 

[hobbsyoyo]

People on Reddit have done the math and it will cost less to build 30 Falcon 9 B5's than just 2 SLS boosters....

That really puts into perspective what a mess the SLS program is

 

[warpus]

I watched the launch of Bangabandhu

Spoiler :

I'm wondering what happens after the video cuts out though? How does the satellite finish putting itself in orbit? Doesn't it have to do a burn at/near the apoapsis? Does it use on-board RCS thrusters for that or something like that?

I'm also wondering what the trajectory of the 2nd stage looks like, does it burn up in the atmosphere in any specific way?

 

[hobbsyoyo]

It has an orbit raising engine. You can see it right on the back of the satellite when it is released (small black circle). It will have to provide ~1500 m/s of DeltaV to raise orbit at apoapsis. It will be in orbit in 7 hours or so. This one looks like a hydrazine engine so it'll happen fast. Electric birds take months to spiral out to GEO from geostationary transfer orbit (GTO) which is where the majority of them are dropped off.

I don't know the specifics of S2's fate. Most S2's burn up uncontrolled a few years after deployment. Some are de-oebited on purpose though this isn't common for GTO missions due to their high energy trajectories and the weight of modern comm sats. SX is supposedly working on S2 re-use so they may do some experiment.

 

[Michkov]

What's an octaweb Mr Hobbs?

 

[hobbsyoyo]

What's an octaweb Mr Hobbs?

It is the structure that all 9 of the first stage are mounted in. It is the thrust structure for the vehicle and provides thermal protection during launch and re-entry. It is called the octoweb because it has 8-way symmetry and is web-like in structure.

NASA is going to fly a small helicopter drone to Mars on the 2020 Rover launch.
https://www.nasa.gov/press-release/mars-helicopter-to-fly-on-nasa-s-next-red-planet-rover-mission

 

[uppi]

The result of the team’s four years of design, testing and redesign weighs in at little under four pounds (1.8 kilograms). Its fuselage is about the size of a softball, and its twin, counter-rotating blades will bite into the thin Martian atmosphere at almost 3,000 rpm – about 10 times the rate of a helicopter on Earth.

Interesting. I never thought about that, but because there is much less air, you need to spin the blades much faster, but at the same time you can spin the blades much faster, because there is less air resistance. If it wasn't for increased friction (always ruining the best physics problems), you would need the same power to generate lift as on Earth.

 

[warpus]

Maybe I missed this in the article, but this thing will be fully solar powered?

 

[uppi]

Maybe I missed this in the article, but this thing will be fully solar powered?

More like battery powered and the battery is recharged with solar power between flights. I doubt there are any other alternatives for such a thing.

 

[Thorgalaeg]

It is a martian Kamov.

 

[hobbsyoyo]

It looks like they are using a 1U cubesat bus as the avionics platform and main fuselage for this vehicle.

It's awesome how adaptable the platform is. Also very Kerbal looking.

 

[Bootstoots]

@hobbsyoyo - Is your website supposed to be down? It had some pretty cool stuff, like a discussion of the most powerful/unstable possible rocket propellants. I hope you didn't have to discontinue it.

 

[hobbsyoyo]

@hobbsyoyo - Is your website supposed to be down? It had some pretty cool stuff, like a discussion of the most powerful/unstable possible rocket propellants. I hope you didn't have to discontinue it.

It's down and I forgot the link was still on my name card. I'll get around to removing it eventually.

I got to a point with my last job where I had no time to write anything new and so I was paying money to maintain the site and my photoshop subscription but not doing anything with it for months so I shut it down.

 

[hobbsyoyo]

ULA selected the RL10/Centaur second stage combination for the first version of the Vulcan rocket. Orbital ATK also selected the RL10 engine for the third stage of their Omega rocket though the tanking will not be a Centaur. This is obviously good news for the company that produces the engines, Aerojet Rocketdyne. That same engine has been used since the 60's. They have been making changes to make it more manufacturing-friendly in the past few years and supposedly the new variant they are making for Vulcan will have a lot of 3D printed parts to drive down costs further.

 

[hobbsyoyo]

The SLS program announced another months-long delay in construction of the vehicle core. Up until now it seemed that the Europeans would be the long-pole in the schedule as they were behind in delivering the service module for Orion but it looks like NASA pulled ahead...err...I mean behind.

Scientists also announced that they found data in old Galileo probe measurements that indicate it flew through a water plume as it passed near Europa years ago. Super exciting!

 

[Colon]

Scientists also announced that they found data in old Galileo probe measurements that indicate it flew through a water plume as it passed near Europa years ago. Super exciting!

Because it confirms there's water or because of what might be in it?