Orbital refueling

[Cosmacelf]

SpaceX and NASA to work together to develop orbital refueling technologies:

NASA agrees to work with SpaceX on orbital refueling technology

My favorite quote:"The game-changing technology that NASA has discovered is capitalism"

 

[Nikxice]

A fascinating takeaway from the news is NASA's acknowledgement of the Super Heavy/Starship program. If there's anybody willing to fact check, I can't recall NASA ever expressing any interest. Quote from the NASA press release, "SpaceX will work with Glenn and Marshall to advance technology needed to transfer propellant in orbit, an important step in the development of the company’s Starship space vehicle."

 

[jdevo2004]

Doing complex things with fuel in orbit seems like a bad idea. Inevitibly something is going to go wrong and two large rockets will be destroyed causing a massive orbiting debris field.

 

[bxr140]

Doing complex things with fuel in orbit seems like a bad idea. Inevitibly something is going to go wrong and two large rockets will be destroyed causing a massive orbiting debris field.

This isn't a huge issue as it is outweighed by the risks present on the ground. While anomalies in space might create a debris field, anomalies on the ground create dead people. So, the safety side of things is pretty well understood.

This is also an evolution of ongoing refueling programs by NASA (Restore-L) and DARPA (RSGS), which are both hypergol based and arguably significantly more risky than CH4 and LOX. One could also argue that CH4 and LOX propellant transfer technology is far more important to space exploration than the old school hypergols.

 

[Grendal]

a different article:
Blue Origin and SpaceX among winners of NASA technology agreements for lunar landers and launch vehicles - SpaceNews.com

 

[Nikxice]

Doing complex things with fuel in orbit seems like a bad idea.

Orbital refueling will be a big first in Space and Elon certainly relishes being at the top of the heap. A good idea, when the hardware and procedures are designed to work safely. The Russians are credited with many early firsts in Space, although some aerial skills won't easily transfer!

 

[CSFTN]

What does a photoshopped picture of a Russian (or Soviet?) fighter flying inverted while purportedly refueling have to do with this thread?

 

[Electroman]

a different article:
Blue Origin and SpaceX among winners of NASA technology agreements for lunar landers and launch vehicles - SpaceNews.com

What has BO achieved anything or demonstrated anything so far in Space tech, that they deserve any funding?

They haven’t even put anything in orbit yet.

 

[ggies07]

Eventually, Congress got the upper hand, putting NASA on track to build the large SLS rocket at a development cost of more than $2 billion a year. The rocket program mostly benefited the Alabama space center and was championed by Alabama State Senator Richard Shelby. The potential of in-space fuel storage and transfer threatened the SLS rocket because it would allow NASA to do some exploration missions with smaller and cheaper rockets. As one source explained at the time, "Senator Shelby called NASA and said if he hears one more word about propellant depots he’s going to cancel the Space Technology program."

I always wonder what life for humanity would be like if we collectively worked together instead of being greedy little monkeys....****ing greed. ****ing small minded people.

 

[favo]

What has BO achieved anything or demonstrated anything so far in Space tech, that they deserve any funding?

They haven’t even put anything in orbit yet.

They aren't getting any money.

The agreements do not provide any funding to the companies but instead allow them to work with NASA centers and tap into their expertise in a range of technologies.

 

[bxr140]

What has BO achieved anything or demonstrated anything so far in Space tech, that they deserve any funding?

Passing over the obvious gaffe that @favo pointed out, your assessment on the linearity of time is accurate. Indeed, one does not have a product before they have a product.

The space industry is almost a worst case example throughout industry, because the investment to create a product is so massive. Instead, what is often demonstrated in order to receive funding is prototype concepts and sometimes prototype technologies, and general capability--both existing and planned--of the company. It is polar opposite to, say, consumer electronics or even automobiles, where the approach is build-it-and-they-will-come. In the space industry, basically nothing happens without someone first giving you money to do something, whether that money comes from investors (like SpaceX) or The Man (for things like the SLS program). In fact, pretty much the first of everything in space is funded by the latter, including predecessors to most of SpaceX's first order advancements, notably landing hardware from flight (Apollo) and reusing flight hardware (STS).

Layering extreme irony to the whole conversation, Blue Origin is basically the only space entity that--to a significant degree--doesn't operate in the fund-me-first way, because their operating budget is largely pulled out of some weird guy's rainy day jar.

 

[ecarfan]

Blue Origin is basically the only space entity that--to a significant degree--doesn't operate in the fund-me-first way, because their operating budget is largely pulled out of some weird guy's rainy day jar.

If only SpaceX could find another uber-wealthy weird guy to fund colonizing missions to Mars! Paging Larry Page...

Back to in-orbit refueling: it is going to be fascinating to watch SpaceX figure out how to do it. I’m looking forward to a livestream of the first attempt.

 

[Cosmacelf]

More background info. No prizes for figuring out who the villain is:

The SLS rocket may have curbed development of on-orbit refueling for a decade

This quote aged well:

"Let's be very honest again," Bolden said in a 2014 interview. "We don't have a commercially available heavy lift vehicle. Falcon 9 Heavy may someday come about. It's on the drawing board right now. SLS is real. You've seen it down at Michoud. We're building the core stage. We have all the engines done, ready to be put on the test stand at Stennis... I don't see any hardware for a Falcon 9 Heavy, except that he's going to take three Falcon 9s and put them together and that becomes the Heavy. It's not that easy in rocketry."

 

[ecarfan]

Let's be very honest again," Bolden said in a 2014 interview. "We don't have a commercially available heavy lift vehicle. Falcon 9 Heavy may someday come about. It's on the drawing board right now. SLS is real. You've seen it down at Michoud. We're building the core stage. We have all the engines done, ready to be put on the test stand at Stennis... I don't see any hardware for a Falcon 9 Heavy, except that he's going to take three Falcon 9s and put them together and that becomes the Heavy. It's not that easy in rocketry."

Interesting. Let’s see... FH first flew February 2018, and then twice in 2019. All successful missions with 6 out of 9 boosters recovered and available for re-use.

SLS has yet to fly and likely won’t fly until 2021. Maybe.

I wonder what Bolden is thinking right now.

 

[Nikxice]

I just rated the Bolden quotes as Funny. The gist of the story concerning Boeing's efforts to put the kibosh on orbital propellant depots deserves plenty of from U.S. taxpayers, especially space enthusiasts.

Great reporting by Eric Berger. Reading his 7 part series on the state of America's space program from 2014 is still quite interesting from the perspective of 2019.
As NASA seeks next mission, Russia holds the trump card | Adrift

From the article @Cosmacelf linked above. "It marked the first time NASA has really formally recognized Starship." Thanks for that fact check Eric!

 

[Cosmacelf]

I wonder what Bolden is thinking right now.

Probably counting his 30 pieces of silver. He was NASA administrator for 8 years. It wasn't NASA's finest period.

 

[Electroman]

Interesting. Let’s see... FH first flew February 2018, and then twice in 2019. All successful missions with 6 out of 9 boosters recovered and available for re-use.

I thought 7 out of 9 boosters were recovered in three missions, only losing 2 center core boosters so far.

 

[ecarfan]

I thought 7 out of 9 boosters were recovered in three missions, only losing 2 center core boosters so far.

One FH center core did land successfully but it was lost while being towed back to land due to heavy seas. If I recall correctly, the Octograbber was not capable of attaching to an FH center core.

 

[ecarfan]

SLS has yet to fly and likely won’t fly until 2021. Maybe.

And now it’s not likely to fly in 2022. But back to the thread topic…

At Elon’s last Starship presentation an animation showed two Starships refilling (his now preferred term over “refueling”) side-to-side instead of what was shown previously which was end-to-end. I wonder why the (tentative) plan changed? Elon previously touted end-to-end as being relatively simple because the tanker after attaching could impart a velocity change such that the liquids could flow without a pump. But side-to-side requires a pumping system which adds weight and complexity, and I would guess more ullage gas on the tanker. Obviously SpaceX has their reasons, I just don’t know what they are.

 

[bxr140]

Elon previously touted end-to-end as being relatively simple because the tanker after attaching could impart a velocity change such that the liquids could flow without a pump.

A few plausible pieces of the pie:

1. Its really acceleration that's doing the lion's share of moving the fluids in the no-pump scenario, not velocity. So for the entire duration of the load transfer the vehicles would need to ~constantly be firing thrusters, otherwise its going to be a pretty slow and ineffective transfer.
2. The orientation of the vehicles is largely irrelevant for the no-pump concept--the vehicles can simply rotate to an orientation that aligns their velocity/acceleration vector opposite the desired direction of fluid flow.
3. There's probably some upside to having valves higher up on the vehicle (as opposed to just using the fill/drains on the aft ends). That's one plausible explanation for them being represented as joined "leeward to leeward". (You don't want to put any hole let alone one for propellants on the re-entry side...)
4. There's some pressurization in the tanks (to mitigate cavitation and pick-up concerns); an active pump can better overcome unfavorable pressures.
5. Differences in molecular characteristics between the fuel and ox (specific gravities, etc.) make a no-pump configuration kind of complicated to get them both right.
6. Sort of a mash up of a few of above, there's an entropy aspect--with no forcing function (pump, vehicle acceleration), generally the propellant loads want to find a happy medium between the combined tanks. That's of course favorable when the target tanks are empty, but when the target tanks really starts to fill up, the liquids will naturally want to go back to the now-less-full tanker (and will make it increasingly harder to keep filling the target tanks).
7. Mostly 'cause some old school concepts are still cool, a paired vehicle set pitched down such that the engines are pointing anti-nadir is the most favorable gravity gradient orientation.