Space Flight Updates - Russia pullingout of ISS?

[deuce]

I still like "Big Fking Rocket"!

I really like that SX doesn't get married to their problems...... Over, under or around.... they don't care.


The fuel transfer mode still hasn't been worked out. I'd like to know more of what Elon means when he says "use thrust to move fuel...

 

[ThreatMatrix]

DM2 Booster landing. Notice how rough the seas are and it doesn't seem to bother the booster.

Edit: That's actually not DM2. Turns out it's a landing in 2016. Still pretty cool.

 

[ThreatMatrix]

I still like "Big Fking Rocket"!

I really like that SX doesn't get married to their problems...... Over, under or around.... they don't care.


The fuel transfer mode still hasn't been worked out. I'd like to know more of what Elon means when he says "use thrust to move fuel...

Instead of pumps. He'll do it by gravity feed, but since there is no gravity he'll create it. The rockets dock back to back. The lead ship is the tanker. In order to get the fuel to feed back the combined ships will accelerate forward. As Einstein said "you can not devise an experiment that can discern acceleration from gravity." As far as the rockets know the tanker is on top and they are both on earth.

The idea probably came from a problem that all rockets have when lighting their engines in micro G. The fuel is just floating around in the tanks. In order to get it to the bottom of the tanks were it can be pumped into the engines you have to give the rocket a little push first. This is sometimes done with something called Ullage motors. Small rockets that give the big rocket a little kick to get the fuel to the back where it belongs.

 

[ThreatMatrix]

FYI
Another Starlink mission aboard a Falcon 9 is to launch Monday night 9:25pm weather permitting. If successful it will mark the first time they have recovered the same booster 5 times. This time aboard Just Read The Instructions which has been in port for 17 months getting extensive upgrades. Also the drone ships Mystery and Mischief have left port to catch the fairings.

 

[deuce]

Instead of pumps. He'll do it by gravity feed, but since there is no gravity he'll create it. The rockets dock back to back. The lead ship is the tanker. In order to get the fuel to feed back the combined ships will accelerate forward. As Einstein said "you can not devise an experiment that can discern acceleration from gravity." As far as the rockets know the tanker is on top and they are both on earth.

The idea probably came from a problem that all rockets have when lighting their engines in micro G. The fuel is just floating around in the tanks. In order to get it to the bottom of the tanks were it can be pumped into the engines you have to give the rocket a little push first. This is sometimes done with something called Ullage motors. Small rockets that give the big rocket a little kick to get the fuel to the back where it belongs.

Seems like that would be a slow process, but I guess there is no great big hurry.

Wonder if they have to purge the tanks first..... some way to balance the tanks.

 

[ThreatMatrix]

That's a good question. I haven't heard the particulars. It wouldn't take much I wouldn't think. Certainly less than a G. You do have to be accelerating the whole time so you do need to burn the whole time.
I don't think a purge is needed. As far as I know gas/air is not forced in to the tanks as fuel is emptied.

 

[ThreatMatrix]

Starlink launch

Booster Landing

Starlinks deployed


No word on catching the fairings yet.

 

[SeabeeGator]

@ThreatMatrix as these are commercially owned, how much is classified? Anything or are they trade secrets for SpaceX only? I have to imagine some of it is classified if they are using critical parts that are used on other tech - such as missiles (I’m thinking telemetry, avionics, software packages, maybe propulsion systems???). The whole thing fascinates me as there is so much programmatic change from what we have done since the beginning.

 

[ThreatMatrix]

@ThreatMatrix as these are commercially owned, how much is classified? Anything or are they trade secrets for SpaceX only? I have to imagine some of it is classified if they are using critical parts that are used on other tech - such as missiles (I’m thinking telemetry, avionics, software packages, maybe propulsion systems???). The whole thing fascinates me as there is so much programmatic change from what we have done since the beginning.

They are commercial owned. SpaceX could use Crew Dragons to fly tourists if they wanted to. And of course some of it is trade secrets. However some of it is also considered national secrets. They still do work closely with NASA so there may be some tricks of the trade that are shared.
I know it's not unusual in other industries (Semiconductor fabrication for example) for the guberment to step in and say "whoa, this is pretty high tech, let's keep it under wraps from our enemies."

 

[G8trwood]

Damn, a thread on gatorchatter where I learned a bunch..Thanks Threat!

world ends tomorrow..

 

[ThreatMatrix]

Another interesting tidbit. So SpaceX is already significantly cheaper than anyone else. A seat on the Crew Dragon costs $55M. Boeing is charging $90M. The Russians charge about the same.
SpaceX can charge less because they can reuse the boosters. NASA however traditionally has demanded that crew be flown in brand new space craft. That's not too much of a big deal for SpaceX because they can just reuse the booster for a Starlink or any other cargo mission. The Crew Dragon is a different story. They do reuse it for cargo missions after ripping out all the weighty life support equipment but still a Crew Dragon is very expensive and NASA has contracted them for 6 missions after this one. That's 6 new Dragons they have to build.
But NASA has so much confidence in SpaceX that they have decided to let them reuse the booster and Crew Dragon for human flight. That significantly lowers the cost for SpaceX. Maybe they only build 2-3 crew Dragons instead. This won't effect the what they are charging NASA for this contract (but it does mean more money in their pocket). However for the next round it will be interesting to see if SpaceX drops the price even further.
Going forward it may even help with the cost of the boosters. SpaceX is going to phase out the Falcon 9 Rocket in a couple of years and use SuperHeavy Starship exclusively. They'll have plenty of Falcon 9 rockets laying around though (The DM2 booster was #58). So they can probably stop building new ones and just reuse whatever is in inventory.

 

[ThreatMatrix]

Apparently they didn't catch the $10M fairings because they haven't released a video. They can instead fish them out of the water but it means more refurbishing after being exposed to sea water.
Here's what it looks like when the catch one (the nets large, about an acre).


Here's what it looks like when they don't. You can see the ship desperately trying to adjust. (all done autonomously).

 

[SeabeeGator]

NASA however traditionally has demanded that crew be flown in brand new space craft.

Say what? Need to elaborate on this because as written, this is completely untrue.

 

[ThreatMatrix]

Say what? Need to elaborate on this because as written, this is completely untrue.

You thinking of the shuttle?

 

[SeabeeGator]

You thinking of the shuttle?

Yes. That would be part of “traditionally”. SRBs were reused as well. My family worked for USBI for decades. If you were talking on platforms similar to what is used now, then I would agree but I think they did a proof of concept on Gemini to show they could - but never did.

 

[ThreatMatrix]

Right. NASA owned the shuttle. For commercial vehicles they've required new craft or at least originally did on this contract. So take "traditionally however you want.

 

[SeabeeGator]

Right. NASA owned the shuttle. For commercial vehicles they've required new craft or at least originally did on this contract. So take "traditionally however you want.

They just started allowing commercial space flight to transport humans hardly any “tradition” there.

 

[deuce]

That's a good question. I haven't heard the particulars. It wouldn't take much I wouldn't think. Certainly less than a G. You do have to be accelerating the whole time so you do need to burn the whole time.
I don't think a purge is needed. As far as I know gas/air is not forced in to the tanks as fuel is emptied.

Wouldn't that create a vacuum in the tank? Would that be good in space(vacuum)?

I guess the forces are working against each other, shouldn't be an issue.

 

[ThreatMatrix]

Wouldn't that create a vacuum in the tank? Would that be good in space(vacuum)?

I guess the forces are working against each other, shouldn't be an issue.

If you think about it does it matter?. As the tank empties the pressure inside gets less however so does the pressure outside the tank. It may even help with refueling in that you'd have a lower pressure (at least initially) in the empty tank.

 

[ThreatMatrix]

They just started allowing commercial space flight to transport humans hardly any “tradition” there.

Well they started the contracts 15 years ago so there's that. Also the Shuttle/SRB's weren't so much reusable as they were refurbishable. Part of the reason it was so expensive.

Edit: SRB's were so expensive to refurbish they determined it would be cheaper to build new ones.