SpaceX SpaceX: First stage landed Satellites in orbit

[mfb]

A great launch, everything worked as expected, delivering 11 OrbComm satellites to Earth orbit (they all got deployed in the minutes after reaching orbit). But that was the routine part... although it was the first flight of an improved version of Falcon 9 1.1 ("Full thrust" version).
The first stage accelerated the second stage to about 1.5 km/s, then separated, turned around, flew back, and landed. It is the first time a rocket stage used for going to orbit has been recovered like that. Certainly a remarkable day in the history of spaceflight.



helicopter view

Full launch, landing and satellite deployment video

Two pictures from the stream (the numbers in the upper right corner are the second stage speed and height).

One satellite gets deployed, the box in the lower middle part of the image:

 

[Bystander]

Finally!

 

[enorbet]

THEY DID IT ! Finally proof of concept is accomplished with this recent successful landing.

http://money.cnn.com/2015/12/21/news/companies/spacex-launch-rocket-landing/index.html

Oh man I am just ecstatic! What a feat.

 

[mfb]

The helicopter view of the landing is better.

 

[mheslep]

Aye. First time in history, right, from a full orbital launch?

e

 

[rootone]

The first stage didn't get into orbit, it's purpose is to get the second stage moving at a sufficient velocity and great enough altitude prior to orbit insertion.
It's impressive engineering though.
Whether or not it pays off in the end depends on whether the soft landed booster stage is in fact re-usable fairly quickly, or whether the refurbishing costs are not very different to building a new one.

 

[mfb]

Using this stage again will certainly be interesting. I didn't see specific plans yet.

The first stage didn't get into orbit, but at least it reached space due to the target orbit of ~650 km - significantly above the ISS, for example.

 

[rootone]

I guess this particular one probably will not be re-used, well not as a whole, maybe parts of it.
More likely a lot of it will be taken apart and examined very carefully to see how components had performed, potential stress failures identified, and so on that could be improved.

 

[mheslep]

The first stage didn't get into orbit, it's purpose is to get the second stage moving at a sufficient velocity and great enough altitude prior to orbit insertion.
It's impressive engineering though.
Whether or not it pays off in the end depends on whether the soft landed booster stage is in fact re-usable fairly quickly, or whether the refurbishing costs are not very different to building a new one.

I know. I'm drawing a distinction between the Falcon mission which reached orbit and landed the 1st stg, and the recent Amazon funded mission which also landed but was only a suborbital mission.

 

[mheslep]

Using this stage again will certainly be interesting. I didn't see specific plans yet.

The first stage didn't get into orbit, but at least it reached space due to the target orbit of ~650 km - significantly above the ISS, for example.

Yes I think I recall from the video that the 1st stage separation occurs at about 10% of the final payload velocity.

 

[mfb]

Stage separation happened at 6000 km/h (and 77 km height), satellite deployment at 26000 km/h. That is 23%.
Full launch video
Vertical velocity seems to be more than 1km/s at that point. A very steep launch profile, but one that helps to get the first stage back to the launch pad.

 

[mheslep]

I've not seen any comment yet on why SpaceX abandoned the barge for landing, or how they gained permission for a landing attempt at the Cape. A demolition charge could not have completely avoided tons of misguided 1st stage raining on the Cape.

 

[rootone]

My guess is that a barge is essentially a boat and it can tilt and move unpredictably due to weather and sea conditions.
Landing on land eliminates the risk that something moves in a weird way that the onboard guidance systems can't cope with.

 

[mfb]

The landing platform is also much larger than the barge.
The previous missions all came very close to the drone ship, I guess the risk of the rocket going completely wrong was not that large. There is also the risk of the launch going wrong, with much more fuel.

 

[mheslep]

... There is also the risk of the launch going wrong, with much more fuel.

Sure, and launches fail occasionally on the pad with all that fuel, but none the less on the pad which is secured for that eventuality. Shortly after launch the vehicle is downrange over the Atlantic.

On more consideration, I imagine that since the 1st stage is also returning from over the ocean the high speed portion of the descent is safe enough, and if there's a deviation from profile in the last ~mile they still have time to destroy it. The Cape is well named; I had opportunity recently to travel down the FL coast close offshore, which is otherwise remarkably straight for hundreds of miles except for the Cape jutting out into the ocean. Its a kind of giant land barge for the FL coast.

 

[newjerseyrunner]

Here is a graphic that I found very interesting to demonstrate the ability of SpaceX

 

[Greg Bernhardt]

Stage separation happened at 6000 km/h (and 77 km height), satellite deployment at 26000 km/h. That is 23%.
Full launch video
Vertical velocity seems to be more than 1km/s at that point. A very steep launch profile, but one that helps to get the first stage back to the launch pad.

This video is fantastic. I love the timeline at the bottom.

 

[Lord Crc]

I've not seen any comment yet on why SpaceX abandoned the barge for landing, or how they gained permission for a landing attempt at the Cape. A demolition charge could not have completely avoided tons of misguided 1st stage raining on the Cape.

The ballistic return trajectory is such that it would land in water. Shortly before landing one engine fires and changes the trajectory so it intersects the landing pad.

 

[Dr. Courtney]

Great stuff. I have a good friend who works for SpaceX.

 

[mheslep]

Here is a graphic that I found very interesting to demonstrate the ability of SpaceX ...

Blue Origin-Amazon's Bezos from doesn't agree there's a credit worthy distinction between the Falcon 1st stage and his suborbital flight. The twitter verse didn't take it well.

 

[Jonathan Scott]

I heard that the barge could still be used to support missions which need more fuel, by avoiding the need to fly back to the launch point.

 

[Greg Bernhardt]

Blue Origin-Amazon's Bezos from doesn't agree there's a credit worthy distinction between the Falcon 1st stage and his suborbital flight. The twitter verse didn't take it well.

I think this makes for a great competition that will only help advance the mission

 

[newjerseyrunner]

Blue Origin-Amazon's Bezos from doesn't agree there's a credit worthy distinction between the Falcon 1st stage and his suborbital flight. The twitter verse didn't take it well.

I disagree, Blue Origin's launch was a proof of concept, SpaceX's was a secondary feature of a fully functional payload delivery, both insanely impressive. I would liken it to the difference between Yuri Gragarian's full orbital flight vs Alan Shepard's suborbital.

I think this makes for a great competition that will only help advance the mission

Agreed, we are entering a very very interesting time in human history, I'm glad I'm alive to witness what will probably lead us to Mars in my lifetime. My impression that Elon Musk secretly hopes that his legacy to humanity will be Mars, and everything leading up to it will be forgotten.

 

[mrspeedybob]

How is this better then the parachute system used by the SRBs from the space shuttle?

There are the obvious benefits...
No cost associated with a recovery ship
No salt water

And the downside...
Additional fuel for the return trip and landing.

Does that about sum it up? What other benefits and downsides are there to this system vs the previous SRB recovery system?

 

[Monsterboy]

https://pbs.twimg.com/tweet_video/CWzGQVnVAAAdhdg.mp4

 

[mrspeedybob]

https://pbs.twimg.com/tweet_video/CWzGQVnVAAAdhdg.mp4

Umm...
That's a link to the pageant fiasco video. Was that an error, or are you trying to say this sort of recovery is just sexier?

 

[Monsterboy]

Umm...
That's a link to the pageant fiasco video. Was that an error, or are you trying to say this sort of recovery is just sexier?

That's the response Jeff got from Paul Gemperlein on twitter
http://money.cnn.com/2015/12/22/news/companies/jeff-bezos-elon-musk-twitter-feud/

 

[enorbet]

Umm...
That's a link to the pageant fiasco video. Was that an error, or are you trying to say this sort of recovery is just sexier?

Perhaps the inclusion of "sexier" came from the rumor that upon the successful landing, Elon Musk yelled "In your falcon face, Bezos!" ;)

 

[dschlink]

The barges are intended to be used for recovering the center booster of the Falcon Heavy, as it will be too far from land to backtrack without severely impacting the payload. They were used for the first trial landings, because SpaceX was having trouble getting permission to do onshore landings; if you read the notes leading up to Sunday's launch, you'll see that permission was up in the air as recently as prior Thursday.

 

[Lord Crc]

And the downside...
Additional fuel for the return trip and landing.

Fuel cost is almost negligible from what I understand. Someone mentioned the entire first stage fuel cost was just 0.7% of the total first stage cost. I can imagine a controlled landing at a pad being much more beneficial than a parachute wayer landing. Hot engine into salty ocean does not sound healthy.

 

[mfb]

How is this better then the parachute system used by the SRBs from the space shuttle?

The boosters were severely damaged by the impact and water and needed months of repair before they could be re-used. The vertical launch is much softer, and the hope is to re-use them within a day. Additional fuel is not an issue - fuel costs are negligible. It lowers the payload for a given rocket size, but if you have a Falcon Heavy or a small payload (and don't have to build a new rocket), this is not an issue.

 

[mheslep]

Fuel cost is almost negligible from what I understand. Someone mentioned the entire first stage fuel cost was just 0.7% of the total first stage cost. I can imagine a controlled landing at a pad being much more beneficial than a parachute wayer landing. Hot engine into salty ocean does not sound healthy.

It's not the fuel cost but the additional mass from additional fuel that is the issue. Payload mass is no more than single digit share of the total, so every additional kg of fuel (and tank and landing struts and ...) for boost back means a kg less of payload. The first step in this achievement was Spacex's breakthru reduction in vehicle mass (outer skin, turbo pump ,...), which then allowed fuel etc for a booster landing.

 

[mfb]

@mheslep: It is a bit better: payload has to go all the way to orbit, fuel for first stage return just has to get accelerated until the first stage engines cut off. That is a huge difference (~factor 5-10?).

 

[mrspeedybob]

How much difference would it make to have a landing pad on the balistic trajectory of the rocket at the time of separation, so that it doesn't have to reverse it's trajectory. Would this add significantly to the payload capacity?

I know this would require either a barge landing or a launch from somewhere other then Cape Canaveral. (Southern Texas maybe? With a landing pad in Florida)

 

[mfb]

I guess you'll have to ask SpaceX. They published some qualitative scheme a while ago, but without numbers. Something like:
Heaviest payload: Falcon Heavy, no reuse of anything, propellant cross-feed
A bit lighter: Falcon Heavy, landing of boosters
Even lighter: Falcon Heavy, landing of all three first stage elements, the middle one with some downrange distance
Even lighter: Falcon Heavy, landing of all three first stage elements close to the launch pad
Very light*: Falcon 9, landing of first stage

*still at ~13 tons to LEO, but very light compared to the 50 tons the first entry gives.

 

[LURCH]

Even watching it live, it didn't look real. That thing just came screaming down out of the sky, blasting flames. Then the flames went out, and I thought it had malfunctioned and was going to crash. Then the engines re-ignited, and the vehicle remained visible all he way down to the tree-line, where it still looked to be dropping too fast.

But it dropped out of site and no fire ball erupted, so that seemed to have gone ok. While I was still wondering if it had landed in one piece, there was this deafening double sonic boom, which made everybody jump; very reminiscent of the shuttle. Then someone watching the video feed said, "they did it; it's down safely!". We all cheered just like the folks at launch control. Never seen anything like that.

 

[mheslep]

@mheslep: It is a bit better: payload has to go all the way to orbit, fuel for first stage return just has to get accelerated until the first stage engines cut off. That is a huge difference (~factor 5-10?).

Rocket equation applies stage by stage. Two stage to LEO is 16.7% non fuel mass, ie rocket and payload, total all stages, +/- a bit depending on fuel choice. Doesn't leave much for payload.
https://en.m.wikipedia.org/wiki/Tsiolkovsky_rocket_equation#Examples

I think single stage rocket-only to orbit is impossible with chemical fuels?

 

[mheslep]

Even watching it live, it didn't look real. ...

:) A couple decades hence, people may look back on the Apollo parachute landings in the ocean, and say, that's nuts, does look real.

 

[mfb]

Rocket equation applies stage by stage. Two stage to LEO is 16.7% non fuel mass, ie rocket and payload, total all stages, +/- a bit depending on fuel choice. Doesn't leave much for payload.
https://en.m.wikipedia.org/wiki/Tsiolkovsky_rocket_equation#Examples

I know - so what? The second stage doesn't care about additional fuel in the first stage. 1 kg of remaining fuel in the first stage is like 1 kg of structural material in the first stage: you just need the "payload" (total second stage+payload mass) to total mass factor of the first stage, not the payload to total mass ratio of the whole rocket.

I think single stage rocket-only to orbit is impossible with chemical fuels?

Or at least so impractical that no one ever did it.

 

[Monsterboy]

I think single stage rocket-only to orbit is impossible with chemical fuels?

Or at least so impractical that no one ever did it.

Skylon's space plane which is currently under development can be considered as a single stage vehicle right ? Well it's not a rocket
https://en.wikipedia.org/wiki/Skylon_( spacecraft )

 

[mfb]

I guess you can count the various ideas of nuclear propulsion as single-staged as well. There are concepts, yes, but nothing that left the ground so far.

 

[cjl]

It's not the fuel cost but the additional mass from additional fuel that is the issue. Payload mass is no more than single digit share of the total, so every additional kg of fuel (and tank and landing struts and ...) for boost back means a kg less of payload. The first step in this achievement was Spacex's breakthru reduction in vehicle mass (outer skin, turbo pump ,...), which then allowed fuel etc for a booster landing.

I don't know that I'd call it breakthrough - the first stage of the Falcon has a full mass to empty mass ratio of something like 20:1, which, while very good, is hardly unprecedented. The Atlas LV-3B from the 1960s had close to 50:1, for comparison, though to be perfectly fair with that comparison, it's worth noting that the 50:1 is after it had dropped off some of its engines (and if you compare empty but with all engines to fully fueled, it ends up closer to 23:1).

 

[mheslep]

Not a comparable payload on the old Atlas, trading payload for fuel. Atlas was a couple tons, I think including the entire capsule. Falcon payload is 13 tons, not including the fairing etc. Falcon 1st stg empty now includes landing struts and aero fins. Lookin at a modern fully 2 stg Atlas, empty to full 1st stg ratio seems to be around 13.

 

[Dotini]

I'm glad the space age has finally caught up to where model rocketry was many decades ago.

In my distant youth, I designed and constructed a 4 stage model rocket, successfully launched, recovered, reloaded, relaunched and again recovered all 4 stages within 30 minutes.

I'd very much like to see man on the Moon again or on Mars. But I'm not optimistic that it'll be accomplished in the foreseeable future.

 

[Monsterboy]

The actual goal is to land the rocket at the same launch pad from where it launched right ?

 

[mrspeedybob]

The actual goal is to land the rocket at the same launch pad from where it launched right ?

I'd be doubly awesome if they could land the second stage on top of it, so that all they'd have to do between launches is re-fuel, and put another payload on top.

 

[mheslep]

I'm glad the space age has finally caught up to where model rocketry was many decades ago

Vice versa, now model rocketry can attempt to catch up to reality and attempt controlled landing using propulsion. I'm unaware of any thrust control used in model rocketry, but it would be required as in the real thing. Guidance on ascent makes use of an innately stable aerodynamic vehicle (fins that place the CP well aft of the CG). Modelers will have to raise their game considerably to match this.

 

[mheslep]

I know - so what? The second stage doesn't care about additional fuel in the first stage. 1 kg of remaining fuel in the first stage is like 1 kg of structural material in the first stage: you just need the "payload" (total second stage+payload mass) to total mass factor of the first stage, not the payload to total mass ratio of the whole rocket...

Yes, sorry, I missed your point in your earlier post.

 

[mfb]

The actual goal is to land the rocket at the same launch pad from where it launched right ?

The launch pad needs support structures that would be in the way for a controlled landing, so I doubt they will use the same pad ever. It's not that hard to move a rocket by a few kilometers, and you need access for some maintenance and putting the second stage on top anyway.

 

[cjl]

Not a comparable payload on the old Atlas, trading payload for fuel. Atlas was a couple tons, I think including the entire capsule. Falcon payload is 13 tons, not including the fairing etc. Falcon 1st stg empty now includes landing struts and aero fins. Lookin at a modern fully 2 stg Atlas, empty to full 1st stg ratio seems to be around 13.

Yes, because they decided balloon tanks are too much of a headache for the modern Atlas, so its structural fraction is worse. There are also quite a few other tradeoffs involved - I'd bet the modern staged combustion Russian engines the modern Atlas uses are quite a bit heavier than the old Atlas engines, for example, though they make up for that with their extremely high efficiency. As for the payload, I'm comparing the first stage's empty mass to its fully fueled mass - payload doesn't come into this at all. You have a valid point about the landing legs and aero fins though - I'm not sure if the number I found included those, and if so, how much those are contributing to the empty mass.