Commercial Hubble Repair

[Jim]

1.  Jim, are you going to argue that there is never, ever, a need to bring back unpressurized cargo?

2.  There is no urgent need for this now, but some day in the future I think it will be developed. If the need did arise soon, of the commercial crew vehicles, DC seems best suited to this because its pressurized crew module can be more easily shortened to open space for a cargo bay.

3 And to state the obvious: when the Shuttle was flying we made use of the return ability several times. I'm sure others can list more than me, but from memory: pump modules, EVA tanks, MISSE experiments, Hubble instruments.

1. No

2.  Just that DC is illsuited for the task.

3.  A very small percentage

Return hardware will become viable on RLV's not reusable spacecraft

[adrianwyard]

Why do you assume they're saying Dragon isn't well suited to satellite servicing? It is possible for both vehicles to be suitable isn't it?

I was just referring to the occasions SNC brags about the servicing capabilities of own vehicle and not the competition.

[oiorionsbelt]

1.  Jim, are you going to argue that there is never, ever, a need to bring back unpressurized cargo?

2.  There is no urgent need for this now, but some day in the future I think it will be developed. If the need did arise soon, of the commercial crew vehicles, DC seems best suited to this because its pressurized crew module can be more easily shortened to open space for a cargo bay.

3 And to state the obvious: when the Shuttle was flying we made use of the return ability several times. I'm sure others can list more than me, but from memory: pump modules, EVA tanks, MISSE experiments, Hubble instruments.

1. No

2.  Just that DC is illsuited for the task.

3.  A very small percentage

Return hardware will become viable on RLV's not reusable spacecraft

Bold mine:
This is an interesting statement.
Care to fill in any details or reasons?

[TomH]

If the mission is unmanned, what about an agreement with USAF to use X-37B?

[Jim]

Bold mine:
This is an interesting statement.
Care to fill in any details or reasons?

When RLV's become economical for launching hardware, it should be economical to return some too.

[RDoc]

When RLV's become economical for launching hardware, it should be economical to return some too.

It seems a bit unobvious that RLV's are a requirement or even particularly relevant. Given a reusable spacecraft, I'd think the marginal cost of returning hardware from orbit would be extremely low. After all, if you're already up there, why return empty handed?

[Robotbeat]

When RLV's become economical for launching hardware, it should be economical to return some too.

It seems a bit unobvious that RLV's are a requirement or even particularly relevant. Given a reusable spacecraft, I'd think the marginal cost of returning hardware from orbit would be extremely low. After all, if you're already up there, why return empty handed?

Because the cost of the return capability is that much more, since you have to pay to get that return capability into orbit.

[RDoc]

When RLV's become economical for launching hardware, it should be economical to return some too.

It seems a bit unobvious that RLV's are a requirement or even particularly relevant. Given a reusable spacecraft, I'd think the marginal cost of returning hardware from orbit would be extremely low. After all, if you're already up there, why return empty handed?

Because the cost of the return capability is that much more, since you have to pay to get that return capability into orbit.

The premise of the discussion is you have a reusable spacecraft to start with. Of course, I'm assuming that if the spacecraft is reusable, that it returns to Earth. It wouldn't apply to something like a GTO/GSO taxi, but I don't think that's what we're discussing.

Anyway, apart from SSTO, whether the launcher is reusable or not has nothing to do with the spacecraft being reusable. Depending on the mass/value tradeoff for a particular mission, it doesn't seem inconceivable that a RLV would be sacrificed to get a heavier mass into orbit. SpaceX estimates a 40% payload penalty for launcher reusability. The cost of reusing DragonLab vs not is roughly the weight of the parachute and having a ship go out to pick it up.
 

<snip>
Return hardware will become viable on RLV's not reusable spacecraft

[Robotbeat]

It does depend, because the ability to return equipment and the extra weight penalty to make that equipment repairable, etc, has to come out of a very expensive expendable launch vehicle of around $10,000/kg to orbit.

[RDoc]

It does depend, because the ability to return equipment and the extra weight penalty to make that equipment repairable, etc, has to come out of a very expensive expendable launch vehicle of around $10,000/kg to orbit.

Within the capability of the launcher, the marginal cost of a Kg to orbit is not anywhere near $10,000, it's probably closer to $200. Once you've launched the first 5000Kg, the next Kg is pretty cheap.

Notice that SpaceX prices their launches by the launch, not the Kg. That means that as long as the mass to orbit stays within the launcher capacity, the marginal cost of launching any return racks not already installed is zero.

For dirty laundry, it may still not be worth doing. For examining why a piece of life support equipment failed early, or getting back a protein synthesis lab to be modified and reflown, it's may very well be.

As far as if repairability adds mass, I'm doubtful that much equipment is put into orbit that can't be factory disassembled. Obviously there are expendables, but even for failed equipment that isn't going to be reused, it's sometimes very instructive to take a close look to see what happened. After all, if you can double the on orbit life, you don't have to fly so many.

[Mongo62]

Getting back to the original Hubble servicing question, would not the cheapest solution simply be to build and launch a Hubble clone (this time installing a correctly-figured main mirror) to replace the entire telescope?

I vaguely recall hearing about a report many years ago that concluded that for the expense of all the various Shuttle servicing missions, several Hubbles could have been built and launched on unmanned rockets (Atlas V?), and we would have ended up with a whole fleet of active telescopes.

[Jorge]

Getting back to the original Hubble servicing question, would not the cheapest solution simply be to build and launch a Hubble clone (this time installing a correctly-figured main mirror) to replace the entire telescope?

Back when HST SM-4 was cancelled, Johns Hopkins proposed using the SM-4 replacement instruments to build a new telescope called the Hubble Origins Probe, for about $1B:

http://www.pha.jhu.edu/hop/

Of course, it would be much more expensive to build HOP now since the SM-4 instruments flew on STS-125.

I vaguely recall hearing about a report many years ago that concluded that for the expense of all the various Shuttle servicing missions, several Hubbles could have been built and launched on unmanned rockets (Atlas V?), and we would have ended up with a whole fleet of active telescopes.

Perhaps in a narrow technical sense. But Hubble was politically tied to the shuttle; had it launched on an ELV with the same original flaws, most likely there would never have been a second one.

[go4mars]

Of course, it would be much more expensive to build HOP now since the SM-4 instruments flew on STS-125.

Thanks Jorge.  Just to clarify; Do you mean that an EELV launch and everything except the SM-4 instruments would be about a billion dollars today, but that re-making the SM-4 instruments (or their current equivalent) would be more than an additional billion dollars?  I didn't notice any $ breakdown in the link.   

[Jorge]

Of course, it would be much more expensive to build HOP now since the SM-4 instruments flew on STS-125.

Thanks Jorge.  Just to clarify; Do you mean that an EELV launch and everything except the SM-4 instruments would be about a billion dollars today, but that re-making the SM-4 instruments (or their current equivalent) would be more than an additional billion dollars?

I assume that the whole thing will be a lot more than $1B due to the need to build new instruments, and because the price of EELV has gone up. They assumed $130-150M for an Atlas V 521, for example.

  I didn't notice any $ breakdown in the link.   

You didn't look hard enough. There is a cost breakdown on slide 20 of the PowerPoint slideshow at the link.

[A_M_Swallow]

With a life expectancy of only a couple more years Commercial Space cannot get a manned capsule to the Hubble Space Telescope in time.

An unmanned repair mission requires development of automated repair robots.  There has been some money going into space robots but not a lot.  Consequently such missions are many years in the future.

Launching Hubble#2.  With a mass of 11,110 kg (24,500 lb) and orbital height of 559 km (347 miles) there are several launch vehicles that can lift its replacement.  In previous years the estimated cost of building a replacement satellite was about $1 billion which suggests a current cost of $2 billion to $3 billion.  The replies to a request for bid for launching a replacement using the current specification within about 3 years could be very interesting.