Reusable launch escape upper stage based on Dragon, to save expensive payloads

[TakeOff]

Wouldn't it be worthwhile for SpaceX to use the launch escape capability of Dragon also on launches without the Dragon by developing a small "upper-upper" stage version of it?


Dragon now flies cargo with its launch escape capability ready. Except for uncrewed spacecraft test launches, and Buran which launched with other kinds of abort modes, this is the first time I know of that uncrewed launches have a launch escape system (LES). I suppose that the traditional launch escape tower simply has not been worth the extra cost and mass. But Dragon has a reusable LES. Could this LES be lifted out of the rest of the Dragon so that it could save a payload if needed, or otherwise separate and land alone?


Are there any obvious show stopper for that idea?
Falcon 9's upper stage is not reused today, and this "escape stage" would have to be on top of that first stage. It would separate when in orbit. Unless the escape stage can be put on top of the payload and separated earlier, as soon as it's too late for a launch abort. Recovering the upper stage from orbit might be motivated if it comes with a Draco LES.

SpaceX competes with price and doesn't yet have a long established launch success record. Customers with especially valuable payloads should give priority to reliability to lower insurance premiums. An LES for uncrewed payloads could help a new company with yet less proven launchers convince the high end of the market and their insurers.

[zodiacchris]

LAS is one thing, but you'll also need parachutes, as the abort would use the fuel for propulsive landing. And even with the chutes, most satellites would probably only be good as garden ornaments after impact. Or immersion in salt water...

[TakeOff]

A Red Dragon might become the first uncrewed interplanetary mission launched with an LES. It could motivate greater investments in its internal payloads since many launch failure modes would only lead to a two year delay to relaunch the same payload.

LAS is one thing, but you'll also need parachutes, as the abort would use the fuel for propulsive landing. And even with the chutes, most satellites would probably only be good as garden ornaments after impact. Or immersion in salt water...

Dragon's launch escape test did look VERY shaky. But everything on a spacecraft is not vulnerable to that, much could be salvaged. It's designed to be safe for astronauts, and spacecrafts have to be made to handle the G-forces and vibrations of a successful launch anyway. Also, Dragon is supposed to land on land (not sea on sea as in the old days), so nasty salty bio active sea water could be avoided.

[Jim]

Are there any obvious show stopper for that idea?

Many, and there are many threads on this that poo pooed the idea.

1.  Loads - Spacecraft aren't designed for the abort, parachute and landing loads
2.  Mass - The encapsulated payload is heavier than Dragon (and that is without an abort system)
3.  Environment - The spacecraft would be without conditioned air for a long period
4.  The encapsulated payload and abort system would have to be designed for a water landing
5.  The spacecraft would be below the horizon of control centers and hence its status could not be determined and controlled.

Edited to provide the proper tense

Poo or pooh, either way, it is an adult way of dismissing something.  Much better word than meh

[Jim]

Also, Dragon is supposed to land on land (not sea on sea as in the old days), so nasty salty bio active sea water could be avoided.

Wrong, not in an abort case.  (a.  the abort is over water.  B. the abort uses all propellant, so parachute landing is mandatory)

[Jim]

A Red Dragon might become the first uncrewed interplanetary mission launched with an LES. It could motivate greater investments in its internal payloads since many launch failure modes would only lead to a two year delay to relaunch the same payload.

No, not feasible. 
Even ignoring all the above reasons that doesn't make it feasible, refurbishing an aborted spacecraft would take longer than the available launch period (usually 20 days or so, but refurb is going to take months)

[RotoSequence]

Are there any obvious show stopper for that idea?

Many, and there are many threads on this that poo poo the idea.

1.  Loads - Spacecraft aren't designed for the abort, parachute and landing loads
2.  Mass - The encapsulated payload is heavier than Dragon (and that is without an abort system)
3.  Environment - The spacecraft would be without conditioned air for a long period
4.  The encapsulated payload and abort system would have to be designed for a water landing
5.  The spacecraft would be below the horizon of control centers and hence its status could not be determined and controlled.

How much extra mass would it take to mitigate #1? 10% more? 20? 50+?

[envy887]

Entry heating is a major issue once the vehicle reaches a certain altitude/speed. Dragon can survive that, but a satellite cannot, nor can the fairing with that much mass behind it.

Aero loads during an abort on ascent are also a major issue. Dragon is stable and can handle those, but the fairing will explode if you turn it sideways during a max-q abort.

[MrHollifield]

First off, to be reusable, it would have to be below the 2nd stage. Super Dracos can't lift S2, so "reusable" is off the table.

To make it work with the LES stage between S2 and the payload:
-Redesign the fairing to be aerodynamic with parachutes and to hold together under 'chutes while falling to water,
-Redesign the fairing to be water-tight,
-Redesign the fairing to always float in an recoverable position with a payload of arbitrary mass and dimensions inside,
-Make sure the fairing still works normally with all this redesign,
-Get every spacecraft manufacturer who wants to get their bus selected to fly on this LES stage to redesign their satellites to handle the loads that would be encountered in an abort and water landing scenario,
-Fly more payloads on FH because the mass-to-orbit is decreased 1:1 by the mass of the LES stage and proportionally by the new water-tight, parachute-equipped fairing,
-Throw away 8 Super Dracos on every launch when they deorbit with S2.

IANARS, so I'm probably missing a few of trade-offs necessary to make this LES stage work.

[RonM]

It would be more cost effective to make F9 and FH more reliable. Then there wouldn't be a need for a payload LAS. Atlas V doesn't need a way to save payloads, it just works.

[envy887]

It would be more cost effective to make F9 and FH more reliable. Then there wouldn't be a need for a payload LAS. Atlas V doesn't need a way to save payloads, it just works.

An optional high thrust hypergolic kick stage between the S2 and PAF would be handy for high energy orbits.

[guckyfan]

It would be more cost effective to make F9 and FH more reliable. Then there wouldn't be a need for a payload LAS. Atlas V doesn't need a way to save payloads, it just works.

It needs to be reliable. If they do only 50 launches a year and one in 100 fail that would mean a stand down every two years. Not sustainable.

[TakeOff]

Part of the extra capacity of Falcon Heavy could be used to allow for an LES stage, and making the return of the whole upper stage together with it profitable too.

An alternative to a reusable LES would be to use the LES as a third stage, to not reuse it, but to boost the payload further once in orbit after separating from today's expendable upper stage. Sacrificing those Draco engines. At some point of risk and value at stake, an LES is certainly profitable. And since some payloads cost 100 times the launcher, and the failure ratio is about 1 in 8 thus far, there should exist a profitable application of the LES which has already been demonstrated by the Dragon.

The payload doesn't need to land in the sea. It doesn't need to be landed hard. While the escape boost itself necessarily causes huge G-forces, those are in the same orientation as the G-forces of a successful launch, that the payload already today is designed and packaged to withstand. LES have been developed to fit human survivability. They can be designed to save payloads too. The CRS-7 that crashed in June 2015 carried expensive cargo (much more expensive than the launcher) such as a docking port, a space suit and one-off life support systems components. I don't think they would've been seriously damaged by a controlled LES landing.

[Jim]

1.  The payload doesn't need to land in the sea.

2. It doesn't need to be landed hard.

3. While the escape boost itself necessarily causes huge G-forces, those are in the same orientation as the G-forces of a successful launch, that the payload already today is designed and packaged to withstand.

4.  LES have been developed to fit human survivability.

5, They can be designed to save payloads too.

6. The CRS-7 that crashed in June 2015 carried expensive cargo (much more expensive than the launcher) such as a docking port, a space suit and one-off life support systems components. I don't think they would've been seriously damaged by a controlled LES landing.

1.  That is just plain silly.  Most of the ascent is over the ocean.  Even a pad abort is going to land on water.

2.  Parachute landings are hard by definition (they are shock loads).  Then that requires huge parachutes with active control and airbags or retros. 

3.  wrong, abort loads are higher. 

4.  They can take more loads.

5.  The issue is not "can it designed",  the issue is that the expense to the rocket and loss in performance spacecraft is not worth the effort.

6.  The discussion is not about the Dragon or manned spacecraft, but other satellite. So the space suit and one-off life support systems components or station logistics don't count, they are packaged differently (in foam) than satellites.    And also, if the  docking port was carried on a manned Dragon, it would have been left behind in an abort.

Again, this is just another non feasible idea.

[Jim]

An optional high thrust hypergolic kick stage between the S2 and PAF would be handy for high energy orbits.

Not really.  it would better just to used S2.  Better ISP and mass fraction

[Kaputnik]

The only way that I could see this being a good idea would be for delivery of specific highly sensitive cargo- for example, fissionable material for an orbital nuclear reactor.
For a bog standard comsat it's too much effort, cost, and mass. A bit like those 'detachable cabin' concepts people have mooted for airliners. Solution waiting for a problem.

[Folgers25]

I have never been up close to a satellite before, but judging from pictures they look like large sensitive boxes

I would not image a large sensitive box would fare very well during a LES firing, chute deployment, then splashdown into the ocean.

If a satellite is lost, call Jake from State Farm.

[meekGee]

I have never been up close to a satellite before, but judging from pictures they look like large sensitive boxes

I would not image a large sensitive box would fare very well during a LES firing, chute deployment, then splashdown into the ocean.

If a satellite is lost, call Jake from State Farm.

That's the point.  It might be technically feasible, but the cost doesn't justify it. 

[envy887]

The sea water problem can be avoided by not launching across a sea.

Falcon 9 will never do this. Other future vehicles may, but by the time that happens Falcon will be obsolete.

[hkultala]

I have never been up close to a satellite before, but judging from pictures they look like large sensitive boxes

I would not image a large sensitive box would fare very well during a LES firing, chute deployment, then splashdown into the ocean.

If a satellite is lost, call Jake from State Farm.

Would all of it be destroyed?
CST-7 is already an example of how an activated LES would have saved several hundreds of millions of dollars of payload value. I don't understand how you guys try to pretend to not understand this.

You mean CRS-7?

AFAIK the value of potentially saved payload in CRS-7 was in the range of millions, not hundreds of millions. Most of the cargo was very cheap, food and clothes etc, but there may have been some slightly more expensive scientific payloads.

The docking adapter it was carrying in the trunk was expensive but it could not have saved even if LES would have activated, as the trunk would have been jettisoned anyway.