SpaceX News

[ladajo]

I missed the live feed, was off working in a hole. However, coming back to check, I find out they punted the launch until tomorrow 0907 EST due to an anomalous sensor reading on the booster first stage.
So exciting.

[paperburn1]

GPS 3-1 goes up today courtesy of a one way Block 5. I wonder if they will try a landing sequence at sea for data collection. Apparently this one is going up hot due to the delivery energy requirement, and thus is deemed not landable. Interesting given it is going to a HEO profile.

Maybe they just want some more target practice, I mean it's not everyday you get to shoot up a spaceship(booster)
but it is odd
3680 kg (#1)
Orbit: 20200 km × 20200 km, 55.0°
Falcon 9 can lift payloads of up to 22,800 kilograms (50,300 lb) to low Earth orbit, 8,300 kg (18,300 lb) to geostationary transfer orbit (GTO) when expended, and 5,500 kg (12,100 lb) to GTO when the first stage is recovered and 4000 Kg to mars. You would think they have enough boost to save this unit. ¯\_(ツ)_/¯ maybe some mice are hitchhiking along.
EDIT
and the short answer is the air-force wants it that way.
The launch will not be following a traditional east coast trajectory instead heading a more northerly route. To accomplish this they loaded more fuel into the rocket.(I believe in hopes of putting the payload closer to the final orbit saving satellite propellant which would add life to satellite operations)
The additional fuel load gives the GPS 3 SV01 spacecraft a launch weight of around 9,700 pounds, or 4,400 kilograms, according to Whitney. That’s more than a half-ton above the satellite’s originally expected weight.
The Air Force also has to comply with a government policy instituted in recent years to avoid leaving spent rocket stages in orbit, and the Falcon 9’s upper stage will reignite after releasing the GPS 3 SV01 satellite to target a controlled destructive re-entry back into Earth’s atmosphere a few hours later. Mission designers had to set aside some of the rocket’s fuel for the de-orbit burn to satisfy the Air Force requirement, which is aimed at preventing space junk.
“And in doing that mission design to include a re-entry to dispose of the second stage, all those taken together levy performance requirements on the Falcon 9 launch vehicle, (and) as it went through mission design, there simply was not enough performance reserve to meet our requirements and allow them — for this mission — to bring the first stage back, as they’ve been doing quite successfully.”

[paperburn1]

To bad it is not a night launch, it would make a nice show for the east coast

[ladajo]

"(I believe in hopes of putting the payload closer to the final orbit saving satellite propellant which would add life to satellite operations)"
Hmm. This is big. Honestly hadn't thought about that before. Although, I know there have been missions in the past where lifetime took a major hit because of excessive burns being needed to get on station. Once they get on orbit robot fueling sorted here in the next couple of years, it will be interesting to see how the launch schedules slow down for heavy lifts, as lifetimes leap.

[ladajo]

And another punt. Same issue as yesterday. Launch date now TBD.

[ladajo]

A series of misfortunate events... punt gain from this morning for weather. No new launch window given yet...
Something REALLY doesn't want this bird on orbit!

[krenshala]

SpaceCats preventing the mice from leaving?

Getting as much delta-v from the first/second stages will definitely save fuel (and thus delta-v) for the payload. Though, it won't take too much to circularize when you are up in HEO (lower orbital velocity, but more work to get up there in the first place). Going from LEO to GEO takes about 4km/s (high thrust) to 6km/s (low thrust) depending on propulsion type, and thus how much benefit you gain from Oberth Effect on the transfer burn (higher thrust, higher Oberth Effect benefit). This has a lower target orbit, but the same math applies. The more delta-v you can get from the booster stages, the less you need to get from the payload's fuel.

[paperburn1]

SpaceX is standing down from Saturday's launch attempt due to strong upper level winds.
decided to play kerbal space instead....

We are now targeting December 23rd for launch of the United States

[hanelyp]

Until we can launch despite common winds, space flight won't be where we want it.

[paperburn1]

Up Up and Awayyyyy...

[paperburn1]

well is seems it is a technology demonstrator he is building.

https://www.nextbigfuture.com/2019/01/t ... opper.html

[Maui]

The demonstrator may end up waiting on a pad, though:
https://www.nextbigfuture.com/2019/01/c ... 0_c_kjcWPF

This thing so far looks like something I would build

EDIT: New pics-- loving the install method for the American Flag decal:
https://twitter.com/austinbarnard45/sta ... 9908691970

[kunkmiester]

Was it here I was reading about him wanting to use steel?

It's not just strength ratios to worry about, a mostly carbon fiber rocket would have a different radiation risk.

[hanelyp]

As I understand it, carbon fiber produces fewer secondaries from cosmic rays than a steel structure. A matter of atomic number.

[Maui]

Yes steel. AFAIK, the reason he’s tweeted about isre-entry heating, not radiation— but the radiation seems like a fair point too. Steel holds strength in high temps unlike carbon fiber. Rather than use an ablative heat shield, active cooling using fuel as the heat sink. Also, he claims to have a new alloy.