# SpaceX: Another Falcon 9 ground pad landing

• SpaceX
Landing the rocket is only the first step - we'll have to see if they can fly the stages again reliably without exchanging and repairing too many components.
Additionally, recovered rockets can be examined to identify areas with accelerated wear. Future revisions can reinforce those areas. This sort of iteration is only possible with recovery.

mheslep
Gold Member
actual game-changer of which the effects will ripple forever.
Bringing the boosters back is the first part of changing the launch game. Successfully reusing them without significant rework is the second part. Heat, vibration loads on launch and recovery, I think, keep that from being simple. So far the 2nd part has not been done. Standing by.

mheslep
Gold Member
Here is a unofficial simulation of Falcon Heavy where all cores return to launch site (13.5 tons payload to low Earth orbit). The boosters separate at 2:43 video time: 87 km altitude, 70 km downrange, ...
Thanks for the simulation link.

At the point of separation, their continued ballistic path seems to have them on the surface at ~470 km downrange. The core booster, seems to make it out to ~600 km downrange (see simulation elapsed time 3:15), or perhaps in range of Bermuda. I imagine the real problem with following the arc further downrange, even if there happened to be an island fortuitously placed, as opposed to cutting velocity and heading back, is the heat of re-entry at maximum velocity.

We'll see how much it will bring down costs. <snip>. SpaceX talked about a 30% reduction in launch costs, that is not much. It is a new technology, of course, future improvements are likely.
I contend that a 30% reduction, as you say, is hopeful still but wouldn't write that off as "not much" since -

1) It is the first reduction of that magnitude not sacrificing safety or performance. At the very least it proves efficient savings are possible and "proof of concept" is an important first step.

2) If they do achieve 30% net reduction just in this specific area of cost this improves the field by making new "players" less dismissive and more inclined to join in the business of Space Flight. It seems less risky and more doable much like the spurt of growth in Aviation after Curtiss entered the field. Soon after, airplanes, which only a few years before were abject failures even for the most advanced and experienced minds, became ubiquitous. Nobody is likely to build a booster in a barn but the progression follows a similar path.

3) It furthers the advancement into a field where little has been "off the shelf" and one-of-a-kinds not only cost more but tend to add up in nasty ways.

SpaceX has already won $4.2 Billion in contracts from NASA and recently another$1 Billion from Google and Fidelity. Even a 2% gain in profitability encourages investors as well as competitors and they haven't even gone Public yet.

First steps are most often small steps but without a first step away from the accepted norm, status quo prevails and progress stagnates. I suppose it is still speculation on my part but the odds do look quite good especially considering the opposite effect of SpaceX "biting off more than it can chew" and falling on it's face from over-reaching. "Nothing succeeds like success", right?

Mentor
I contend that a 30% reduction, as you say, is hopeful still but wouldn't write that off as "not much" since -
It is not much compared to the general range of payload prices. A typical price tag on "just deliver a few tons to low earth orbit" is in the range of $10,000 to$20,000 per kg, depending on the rocket and the payload mass. SpaceX charges about \$5,000. That is a factor 2-4.

Of course, mfb, I understand those numbers but I wonder if you're considering that given a return to flight-ready there is no currently known reason that the recovery cannot continue for many iterations. It may not be log like compound interest, but it does add up. Furthermore while the term "bottom line" has become commonplace in the lexicon, management knows it is the next to bottom line that is what is important - variable costs. A progressive reduction of that line insures a growing bottom line and while government funded organizations like NASA are certainly very concerned with cutting costs, it is rare that their existence depends on it once they get big. Private Enterprise, OTOH, lives and dies by that bottom line and since variable costs is the only area where control is possible and practical, they hire experts in that field whose concerns never soften with growth. NASA instead hires consultants great with grants and funding.

I have little to go on but the nature of technology business but every aspect of that, whether airplanes, jets, computers, etc. follows a similar path. Once commercialized and made possible for private startups to seriously compete, rapid growth and innovation follows. I'm far more interested in Science than Business but I am also aware that nothing of much import happens without finances and I see "reusable" proof-of-concept as a start of an extremely important progression, even if that first step proves to be minimal but also cumulative, not to mention, inspiring.

Jonathan Scott
Gold Member
Here's an article on the potential cost savings from reuse, including the various factors which make this difficult to estimate at this stage:
http://spacenews.com/spacexs-reusable-falcon-9-what-are-the-real-cost-savings-for-customers/
One of the assumptions appears to be that in the short term, while reuse is still somewhat experimental, any savings achieved via successful reuse are mainly expected to increase the profit margin for SpaceX rather than being immediately passed on to the customer, but it has been suggested that SpaceX may initially provide a discount for customers who accept a launch on a reused first stage.

Mentor
Of course, mfb, I understand those numbers but I wonder if you're considering that given a return to flight-ready there is no currently known reason that the recovery cannot continue for many iterations.
That is considered for the 30%. Reducing the cost by 50% to 75% (Falcon 9 expendable) is a larger effect than reducing it by 30% (reusability of Falcon 9).

A mature, fully reusable rocket (the second stage of Falcon 9 is not reusable) can potentially decrease costs much more, but Falcon 9 won't be such a system, at least not in the next years.

Thank you Jonathan and mfb for further clarification. I suppose in one respect it's a "how far back you wanna go" rather than a "first step" since it is all a continuum, but even within that there are milestones. Robert Goddard's determination and willingness to move residence and risk furious neighbors and possible incarceration is one of those, I think you'd agree. (makes me wonder how Homeland Security would react to an analogous activity today. I used to get my Father to buy KNO3 at the local pharmacy for the "caramel candy" propellant I was using for a time around 1961 for my model rocketry experiments and I very much doubt that is possible anymore, let alone the Zinc dust, Magnesium dust, and Sulphur I could get through the US Postal Service then .)

While reusable boosters pale in comparison to Goddard's contribution, that may still prove to be a key catalyst to Proactive Dreamers who grab onto anything encouraging to make dreams real. It is my understanding that the main developer of the Ion Engine pursued that goal because Scotty ( I'm givin' her all we got now, Captain) was in awe of an alien ship with Ion Drive and apparently his story is not a solo act. Dreamers, and Elon Musk, for all his accomplishments I think must be considered such given all of his ventures and perhaps especially the unrealistic Mars One goals. That said, Mars One despite it's all too obvious flaws, has and is still stimulating those who don't know or can't admit how far away that technology really is. Often, such people can be breakthrough inventors just because they are unaware "it can't be done". Then, of course they lean on engineers to do the impossible :)

SpaceX has truly made remarkable strides in the field of rocketry. It's crazy to think that, years ago, we had no choice but to let first stage boosters plummet to the earth's surface. Seeing a massive rocket land vertically after sending a payload into outer space is simply enchanting.

As far as I know two boosters got moved out. One is supposed to stay somewhere for display, not sure about the other one. But that tweet is not so far off - they either have to start launching re-used boosters in a rapid rate, or find some other place to put them.
Static testing on a used core in Texas, haven't heard any comments on performance, however it did the full burn time so that's a good sign.
http://spaceflight101.com/returned-falcon-9-booster-fires-up-for-full-duration-ground-test-in-texas/

the satellites carried by the spaceX rockets , what do they do, that is -what commercial use ?
I haven't come across a manifest list of all flights, however communications satellite operators seem to be the main customers.

Mentor
As usual, Wikipedia has a list

The core that was used in the test firing is not expected to fly again, but still good to see that it works.

but still good to see that it works.
If I'm not mistaken, the core in question is from one of the "high energy missions" so still being able to perform is very impressive.
Thanks, the wiki article was very interesting, it seems the telecom sats have been big business so far but they are going to be making room for more and more science oriented payloads. (on test flight two I found the test payload to be somewhat amusing) The "secret" test payload on this mission was a wheel of cheese.

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As an update to post #36, I noticed that the core test in question consisted of three firings over three days with good results, very impressive!
From, https://www.nasaspaceflight.com/2016/08/spacex-falcon-9-preparation-jcsat-16-amos-6/
"Despite suffering "max damage" from
its high velocity return, a major
milestone in the goal of reusing
returned first stages for additional
missions was achieved via three full
duration firings in the space of three
days."

Mentor
The next Falcon 9 launch is scheduled for the night from Saturday to Sunday (2 hour launch window starting Sunday 6:26 am CET, 12:26 am east coast, Saturday evening for the other US time zones).

It will deliver a satellite to geosynchronous transfer orbit, which needs more fuel than the ISS launches. The first stage will attempt to land on the drone ship to save fuel, but the landing is still more challenging because the margins are smaller.

This is the first re-entry damage control modification I've heard of, It will be interesting to see how successful it is.

"No surplus propellant is available for a boost-back maneuver and Falcon 9
will be looking at another high-energy re-entry similar to that on the
JCSat-14 mission that left the booster with what was characterized as
‘maximum damage.’
However, SpaceX is hopeful to recover future GTO boosters in better shape
using newly developed techniques to protect the first stage engines in flight.
Due to the vehicle’s orientation, the engines face the most challenging environment
during entry explaining why SpaceX was looking into procedures using onboard
resources to protect the engines. Activities such as flowing Kerosene through the
engines can assist in easing the thermal environment of the engines and a)
ensure they can ignite for landing and b) preserve their condition for re-flight."

mfb
Didn't the tongue-in-cheek term "unscheduled disassembly" bring a wry smile to your face? I love the bravado and humor that SpaceX brings along with a real Pioneer Spirit. I sincerely hope all goes well. They've rather earned it.

Mentor
The next Falcon 9 launch is scheduled for the night from Saturday to Sunday (2 hour launch window starting Sunday 6:26 am CET, 12:26 am east coast, Saturday evening for the other US time zones).

It will deliver a satellite to geosynchronous transfer orbit, which needs more fuel than the ISS launches. The first stage will attempt to land on the drone ship to save fuel, but the landing is still more challenging because the margins are smaller.
And we have another landed stage, number 6 in total, the 4th successful drone ship landing out of 9 attempts.

Video here although the landing itself is not visible, the usual communication problems while a rocket is trying to land there - we'll probably get some better video in the next ays.

On the mission timeline, SpaceX replaced "experimental landing" by "landing attempt". They seem to get more confident.