Boeing Starliner

These delays are painful to watch. Doubt there is any accountability, heck someone will probably get promoted with these delays (F up and move up the ladder)

 

Boeing received $5 billion development cost funding from NASA (SpaceX received 1/2 that to develop its successful Crew Dragon)....Boeing has put in at least another $1.5 billion and still hasn't gotten off the ground.

 

The primary goal of any publicly funded project is to get more funding. Any other results are strictly coincidental.

 

The Atlas V, powered by a Russian engine, has been very reliable. !st scrub was valve problem in 2nd stage, recent scrub was issue with ground control computers.

 

ULA is a joint venture between Lockheed and Boeing

 

Nice launch. I could comment that launching a couple of people into orbit really isn't a big deal for Space X and they reuse their booster. Star Liner has a long way to go.

 

I don't like use of solids for manned flight. Otherwise, ho-hum except for the fact it took them so long and a few more $ than Musk.

 

Solids did not work out perfectly for the STS.

 

Sure the joint, but what I don't like is the on/off feature. Once you light the boosters your options are immediately reduced.

 

So was this a one way trip? Does SpaceX have to go rescue them? Dragon has room for 6 or 8, right.

 

Yeah, not a good look

 

The helium provides the RCS for reentry. Now they just have to calculate whether the leak rates exceed the amount needed to keep the vehicle pointed in the right direction for reentry. And hope they get it right. Assuming they can top up the helium from the station.

 

I believe that would be an incorrect assumption. The design doesn't appear to take into account that helium could leak out while attached to the station. If it goes flat, it would likely take a special trip by a dedicated team with equipment designed to operate in a vacuum and zero G to refill those tanks.

If they determine the helium pressure is too low for the capsule to survive, it would likely be filled with trash and ditched.

The ISS itself has no onboard helium.

 

Why do they use helium? SpaceX uses "storable hypergolic propellants" (like hydrazine) for their RCS. I get the inert gas perspective but effectively they have been chasing this leak for months. I'm sure the amount of stored helium pressure must be ridiculous to match the effectiveness of a propellant.

At what point do you just say: "We screwed up with this NASA/Boeing design and need a Falcon launch to bring the astronauts home"?

 

Generally, helium is used to pressurize the propellent tanks.

 

Helium is used on a large number of space systems for reaction control. While it has a lower Isp than hypergols, it is also much simpler and usually lower risk than relatively nasty hypergolic propellants. Bad news is the helium molecule is very small and can leak easily through any miniscule opening in lines or fittings. The helium tanks are also very high pressure, typically around 8000 psi, and this can also make it easier for leaks to develop short of the pressure regulator.

Those high pressure tanks can also be a danger in themselves. One of the programs I worked on, Modular Insertion Stage, had a helium tank blow up during filling from being overpressurized due to a faulty pressure gauge. Took out the stage, another nearby experimental stage, and luckily only broke the arm of a tech in a plywood safety enclosure nearby.

As John mentioned, helium is also used to pressurize propellant tanks for obvious reasons.

 

Watch SpaceX Crew-8 astronauts move their Dragon at the ISS on May 2 | Space
There is already a SpaceX Dragon at the station, so at least the Starliner test dummies have a ride home.