One more lunchtime post.

First of all, go check out The Space Review. Jeff has some more good pieces up, and he's written one on Saving Private Hubble. He's got some alternatives to it (as does Jay Manifold). Clark Lindsey agrees that it isn't worth a half a billion dollars to save it (see February 3rd entry).

But it's worth pointing out a fallacy here, that's a consequence of the weirdness of space budgets and costs. We won't save half a billion dollars by not saving Hubble. That's the average cost of a Shuttle flight, not the marginal cost, and most of that money will get spent regardless. If we're going to fly Shuttles at all, we're going to spend a few billion dollars a year, regardless of flight rate or where they fly to.

The real factor in deciding whether or not to fly the mission is a) whether or not we're willing to risk the vehicle (I'm already on record as thinking that a reasonable bet, particularly considering the fact that we're going to shut the program down in a few years anyway, and wouldn't necessarily miss it that much) and b) the opportunity cost of flying to Hubble, versus flying somewhere else (in this case, ISS is the only alternative). If all conceivable ISS missions are each more valuable to the nation than continued Hubble operations, then Hubble should die. In my opinion, however, a Hubble servicing missions has more value than the delay of any single ISS mission. And risk to crew shouldn't be a consideration at all. If it's a valuable mission, it's their job to risk their lives to carry it out.

Of course, the value of coming up with an innovative way to save Hubble without using a Shuttle launch would be highest of all.

What *is* the marginal cost for a shuttle mission?

And is the shuttle schedule so maxed out that there is an opportunity cost?

Marginal cost is probably somewhere between a hundred and a hundred fifty million. But yes, NASA generally operates in a mode that launches vehicles as fast as it can within the constraints of safety procedures--it's almost always "maxed out" by definition (including now, when they're not flying at all...)

NASA could use some of the $20 million in the Centennial Challenge portion of their new budget to offer a prize for repairing Hubble. Even the full amount probably isn't enough to entice any serious attempts, but you never know.

"In my opinion, however, a Hubble servicing missions has more value than any single ISS mission"
Now, every planned ISS flight is officially a step closer to finally getting rid of both the ISS and STS.
This has got to be of value.

I didn't say that ISS missions have no value. I just said that a Hubble servicing mission has more.

It just occured to me that canceling the hubble sm4 is having the effect of stimulating congress to pump additional money into NASA. If one were generous, one could imagine that this was a sly plan to get additional earmark funds from congress.

I tend to be in agreement with the new direction for NASA; the shuttle now has a programmed, logical end point, ISS costs and foci are better
defined, and NASA is pointed toward a more inspiring direction.

IMHO, it would be a good outcome if the sm4 mission was funded by congress by adding $$ to the NASA budget. Hubble (and the science it produces) deserves a little more life. Isn't it ironic that ISS gets billions and produces close to zero useful scientific return (the leading public justification) while Hubble produces greatly but lacks for one additional marginal shuttle flight?

I understand the safety concerns, particularly meeting all the bureaucratic CIAB requirements wrt. on orbit repair, but these are just an arbitrary criteria -- we have flow without them before with great success, and one more mission could be done with relatively greater safety. Bottom line is this: it is worth it to fly the
mission. The unstated budgetary savings reasoning doesn't seem particularly compelling either. What would the true cost of sm 4 be in the current NASA budget? Marginal costs might lower than you think, if for example SRBs and ET are already sunk costs.

It would be great to have Hubble boosted up to a 1000 mile, essentially permenant orbit instead of dropping it in the pacific when the end comes. My understanding is that this requires significantly
more dV than deorbiting. What are the actual numbers?

Cheers

Fred

I'd like to not see anything deorbited once we've gone to the expense of putting it, whatever it is, up there. If nothing else the 'stuff' up there might be useful at some point as raw material for other uses.

Rather than letting Hubble burn why not a mission to move it to the ISS orbit, then the Shuttle could still go to it for servicing and upgrades. I presume that there are hardpoints on the telescope that a robotic orbital transfer vehicle could latch on to to make the move. Is it just me or is this the kind of stuff that we should have been able to do decades ago...Get NASA out of space (operations).

Hubble currently orbits far higher (by about 220 km) than ISS. If you were to drop it to ISS's orbit you would need a lot more fuel to maintain that orbit, and (I guess) more exposure to destructive atomic oxygen. If you were to put HST in a high, ISS inclination orbit, it would rapidly go out of phase with ISS and flights from ISS would be limited to brief launch windows. And these problems don't even considering inclination.

The only cost effective way to make such a vast change in inclination would be using some sort of ion drive - however the need to integrate thrust over long times would make Hubble nearly unusable as an astonomical instrument for several years.

SM4 and SM5 (I think an excellent candidate for the last shuttle mission) are probably more realistic nearterm alternatives for Hubble. The Hubble orbits too high for any near-term private piloted launch vehicles (ie next two-four years) who should be focused on more profitable markets anyway. And a robotic 'solution' would kill Hubble as a scientific instrument - if you are going to put the required fine pointing capacities in a robotic stage, you might as well throw in a mirror and launch Hubble II.

I hate to think what would happen if Webb fails, and Hubble is not available.

I hate to think what would happen if Webb fails, and Hubble is not available.

Yes. I got on the receiving end of that point. If we let Hubble go, and Webb doesn't deliver, then how many years will it be before another telescope of that caliber is constructed? Another weak link in the space "program".

The Hubble Space Telescope should be saved. Though the cost is expensive, only about two more Service Missions would be needed until JWST is ready for launch in 2011. By letting Hubble die, valuable information will not be given to scientists inbetween the time of death and the launch of JWST. This also goes along with the possibility of JWST not working; without Hubble, who knows how long it would take to get another telescope up there. Overall, Hubble has proven to work well while receiving regular service missions; it would be a disaster and harmful to space exploration scientists to end the program now. Revive Service Mission 4!