[Coco] Re: Re: off-topic, space program

[Lawrence Weeks]

Once upon a time (Sun Jan 18), Gene Heskett wrote:

> On Sunday 18 January 2004 00:42, Lawrence Weeks wrote:
>> Once upon a time (Sat Jan 17), Roger Taylor wrote:

>>> I wasn't aware that the Hubble had an expiration date on it...
>>> makes no sense at all.

> Nor to Me Roger. To throw that away seems criminal.

Hubble had a ten year designed mission lifetime, and hopefully fifteen
years of actual life. As it was launched in 1990, it is almost there.
Hubble was designed in a Shuttle-centric way. It originally was
intended to be brought back to Earth every five years for service
ane refit, and then relaunched. That didn't pan out, even before the
Columbia breakup. It simply wasn't designed to last in space for
years and years on its own, and we can no longer justify the risk
of special missions to service it. Personally, I think the odds of a
shuttle disaster again so soon are pretty slim, but just imagine if
it did happen? You think NASA wants to take that risk, to service
a space telescope that is beyond its design life and is scheduled
for replacement?

> However, this is 2004, and the Webb launch was set assuming a working 
> shuttle. I submit that the 2010 launch date for the Webb will be 
> shoved back ...

Webb is designed to be launched by a rocket, currently the European
Ariane 5. If the Ariane doesn't work out (those things haven't
started out too reliable), though, they could use a Titan. Webb is
designed to go out to a Lagrange point, about 1.5 million miles from
Earth. NASA decided a while ago not to load booster rockets into the
Shuttle anymore if it can be avoided, so Webb was designed from the
beginning to be launched by itself.

> First, its my understanding that the Hubble is at an altitude thats 
> nearly beyond the shuttles reach in the first place, placed there so 
> that its orbit would not decay as quickly as the ISS is doing.  Did 
> they not burn everything they had the last time and still have enough 
> for the retro-burn, raising its orbit another few miles at both SM2 
> and SM3? Another few miles that may have taken it somewhat beyond 
> the operating envelope of the only shuttle equipt with an arm without 
> stripping it to the bone and beyond.

Yes, Hubble is currently at around 300nm... right around the maximum
for a shuttle. Hubble has no thrusters or propellant aboard, only a big
flywheel for spinning around. The shuttle does boost it, but not that
much really. The biggest was 8.6 nm in 1997. They say that worst case,
Hubble will now re-enter in late 2013. Nominal case, re-entry in 2022.

Personally, I wouldn't be surprised if Hubble is saved later. They are
working on a two gyroscope software solution. It that works, Hubble
would likely continue to operate into the next decade. If we get our
new spacecraft working by then, they could send up a capsule with a
cargo canister to work on Hubble. They could attach a mating target,
and then remotely attach a booster like the Russians do, and boost
whenever we like by sending up a booster stage. Doing all that would
still probably be a good bit cheaper than a shuttle mission, and would
be an excellent demonstration of capabilities with a new launch system.

The Webb telescope has a somewhat different mission from Hubble,
so having both would be scientifically valuable.

> While I deplore the loss of life possibilities, they, the flight
> crew, did know there was a risk, thats its not exactly a sunday
> drive you know.

> I don't see as there is any "proportionately greater" risk to doing 
> SM4. The risk seems to be entirely during the launch and re-entry 
> phases, with a possible colision with an orbiting 3/8" nut while in 
> orbit being possible, but rather vanishingly small in the overall 
> scheme of things.

> I'd a lot more believe that its purely the money involved, with the 
> decision being made by someone who has no concept of the value of the 
> research the Hubble is doing.

I went to college for astronautical engineering, at Purdue. I studied
in Grissom Hall (a building with, ironically, one of the world's
slowest elevators). We have a tree planted in front that went up as
a seedling on an early Apollo mission I believe. I'm definitely on
the same page regarding the risk, and I am pretty positive that the
astronauts scheduled for the Hubble mission wouldn't hesitate for a
moment to do it.

However, this is entirely about money, politics, and cost/benefit
analysis. The new NASA director is Sean O'Keefe. He replaced Dan
Goldin. Goldin was a space nerd. O'Keefe is a budget person. He had
no aero/astro background before NASA. His mission is to rein in that
place. NASA does great work. But they need somebody like O'Keefe. He
will save the place, ironically. This Hubble decision makes sense. The
new Bush mandate is fantastic for NASA. Most space people are quite
happy about it. Some may not like some details, but overall it is
absolutely the best thing for NASA in decades.

Why? Because they actually have a mission to work toward. Bush
apparently got some good advisors (they've been working on this new
NASA mission for a while). And Bush's style is great for this. He
didn't announce yet another Blue Ribbon panel to gab for years,
with public hearings and Congressional pissing matches. He gave clear
direction: the shuttle program WILL BE grounded in year X. NASA WILL
develop a replacement vehicle. And that vehicle WILL BE designed
to support missions outside of LEO; the moon and Mars. The next
day, O'Keefe announces internal changes at NASA. NASA people are
again charged up, because they have goals to accomplish. These
guys are mainly engineers. Give them no deadlines, they'll putz
around forever. Give them dates, and they'll work their asses off to
accomplish the goal, and hopefully develop some cool new, and useful,
technology along the way. Also note that Bush didn't make the huge
mistake of saying that doing this will cost $$$ and ask Congress
for money. Rather, the goal is to increase the NASA budget by a
small amount yearly, and redirect funds internally. This is entirely
reasonable and feasible.

>> Hopefully the two science instruments scheduled for installation
>> during SM4 will be able to fitted to Webb or another orbital
>> platform.

> What were/are those Larry?

A new digital imaging camera, with updated technology. The current
camera is ten years old. The other is a new ultraviolet scanner.

> Refresh my failing memory please as I haven't followed this as avidly 
> as I should have been. And how difficult would it be to fit them 
> into the Webb scopes framework?

Honestly, it is probably too late for Webb. Webb is designed as a
sealed box, with a finite lifetime, since it is going so far away. But
one can hope.

Larry
-- 
Lawrence Weeks                                    lweeks at anabasis.net
Anabasis Consulting Ltd